1
|
Wang C, Chen W, Xu Y, Fu S, Fu J, Huang X, Xiao J, Liu T, Jiang X. Laminaria japonica Polysaccharides Improves the Growth Performance and Faecal Digestive Enzyme Activity of Weaned Piglets. Vet Sci 2023; 11:11. [PMID: 38250917 PMCID: PMC10821088 DOI: 10.3390/vetsci11010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/14/2023] [Accepted: 12/23/2023] [Indexed: 01/23/2024] Open
Abstract
The aim of this experiment was to investigate the effect of Laminaria japonica polysaccharide (LJP) supplementation at levels of 100, 200, or 400 mg/kg on the growth performance, faecal digestive enzyme activity, and serum biochemistry and amino acids of weaned piglets. One hundred and twenty weaned piglets (Barkshire × Licha Black, 21 days old, 6.13 ± 0.16 kg) were randomly divided into four groups with five replicates of six piglets in each group based on body weight. Piglets were fed with different levels (0, 100, 200, and 400 mg/kg) of LJP for a 21-day trial. On day 21, faecal and blood samples were collected from one piglet per pen. The results showed that the supplementation of the 200 and 400 mg/kg LJP significantly increased average daily gain (ADG) and average daily feed intake (ADFI) compared to the control group (p = 0.007; p = 0.002), and dietary LJP linearly increased ADG and ADFI (p = 0.002; p < 0.001). In addition, the supplementation of the 200 and 400 mg/kg LJP significantly increased faecal amylase activity (p < 0.001) compared to the control group, and dietary LJP linearly increased faecal amylase and lipase activities (p = 0.001; p = 0.037). Moreover, dietary LJP at 400 mg/kg increased serum histidine content compared to the other groups (p = 0.002), and dietary LJP linearly increased the contents of serum histidine and asparagine in piglets (p < 0.001; p = 0.046). In conclusion, supplementation of 200 and 400 mg/kg LJP could enhance growth performance and faecal digestive enzyme activity and modulate the serum amino acid content of weaned piglets, potentially contributing to the health of weaned piglets.
Collapse
Affiliation(s)
- Chengwei Wang
- College of Life Science, Jiangxi Science and Technology Normal University, Nanchang 330013, China; (Y.X.); (S.F.); (J.F.)
| | - Wenning Chen
- Key Laboratory of Feed Biotechnology of the Ministry of Agriculture and Rural Affairs, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
| | - Yun Xu
- College of Life Science, Jiangxi Science and Technology Normal University, Nanchang 330013, China; (Y.X.); (S.F.); (J.F.)
| | - Shaomeng Fu
- College of Life Science, Jiangxi Science and Technology Normal University, Nanchang 330013, China; (Y.X.); (S.F.); (J.F.)
| | - Jiamin Fu
- College of Life Science, Jiangxi Science and Technology Normal University, Nanchang 330013, China; (Y.X.); (S.F.); (J.F.)
| | - Xiaohong Huang
- Jiangxi Biotech Vocational College, Nanchang 330200, China;
| | - Junfeng Xiao
- Key Laboratory of Swine Nutrition and Feed Science of Fujian Province, Aonong Group, Zhangzhou 363000, China;
| | - Tao Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA;
| | - Xianren Jiang
- Key Laboratory of Feed Biotechnology of the Ministry of Agriculture and Rural Affairs, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
| |
Collapse
|
2
|
Posey EA, Davis TA. Review: Nutritional regulation of muscle growth in neonatal swine. Animal 2023; 17 Suppl 3:100831. [PMID: 37263816 PMCID: PMC10621894 DOI: 10.1016/j.animal.2023.100831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/31/2022] [Accepted: 01/06/2023] [Indexed: 06/03/2023] Open
Abstract
Despite advances in the nutritional support of low birth weight and early-weaned piglets, most experience reduced extrauterine growth performance. To further optimize nutritional support and develop targeted intervention strategies, the mechanisms that regulate the anabolic response to nutrition must be fully understood. Knowledge gained in these studies represents a valuable intersection of agriculture and biomedical research, as low birth weight and early-weaned piglets face many of the same morbidities as preterm and low birth weight infants, including extrauterine growth faltering and reduced lean growth. While the reasons for poor growth performance are multifaceted, recent studies have increased our understanding of the role of nutrition in the regulation of skeletal muscle growth in the piglet. The purpose of this review is to summarize the published literature surrounding advances in the current understanding of the anabolic signaling that occurs after a meal and how this response is developmentally regulated in the neonatal pig. It will focus on the regulation of protein synthesis, and especially the upstream and downstream effectors surrounding the master protein kinase, mechanistic target of rapamycin complex 1 (mTORC1) that controls translation initiation. It also will examine the regulatory pathways associated with the postprandial anabolic agents, insulin and specific amino acids, that are upstream of mTORC1 and lead to its activation. Lastly, the integration of upstream signaling cascades by mTORC1 leading to the activation of translation initiation factors that regulate protein synthesis will be discussed. This review concludes that anabolic signaling cascades are stimulated by both insulin and amino acids, especially leucine, through separate pathways upstream of mTORC1, and that these stimulatory pathways result in mTORC1 activation and subsequent activation of downstream effectors that regulate translation initiation Additionally, it is concluded that this anabolic response is unique to the skeletal muscle of the neonate, resulting from increased sensitivity to the rise in both insulin and amino acid after a meal. However, this response is dampened in skeletal muscle of the low birth weight pig, indicative of anabolic resistance. Elucidation of the pathways and regulatory mechanisms surrounding protein synthesis and lean growth allow for the development of potential targeted therapeutics and intervention strategies both in livestock production and neonatal care.
Collapse
Affiliation(s)
- E A Posey
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - T A Davis
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
| |
Collapse
|
3
|
Guan X, Santos RR, Koopmans SJ, Molist F. Effects of the Inclusion of Dietary Bitter Gourd ( Momordica charantia) on the Performance and Carcass Characteristics of Pigs: Potential Application in the Feed Chain. Animals (Basel) 2023; 13:2159. [PMID: 37443956 DOI: 10.3390/ani13132159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/02/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
The objective of this study was to determine the effect of bitter gourd (BG) leftovers (stems and leaves) as an alternative dietary ingredient on pig performance, carcass characteristics, serum parameters (urea, insulin, and leptin levels), and faecal consistency. Healthy Tempo × Great Yorkshire and Landrace pigs (N = 240; 120 gilts and 120 boars) weighing 25.8 kg (9-10 weeks of age) were randomly assigned to three treatments (eight pens per treatment; each pen with five gilts and five boars). The three treatments consisted of a non-supplemented commercial diet (control; CON) and a CON diet supplemented with 6.5 g/kg BG (BG1) or 13 g/kg BG (BG2). Pigs were fed the experimental diets until slaughter (120 kg body weight; BW). Feed intake was recorded daily and calculated for each experimental phase (i.e., days 0-36, days 36-66, days 66-98, and the overall experimental period). Average daily feed intake (ADFI), average daily gain (ADG), and feed conversion ratio (FCR) were calculated. The frequencies of visiting the feed station and of feeding were recorded daily. Faecal scores (FS) for consistency were measured per pen twice weekly. On the day of slaughter, two pigs per pen (one male and one female) were randomly selected for the measurement of muscle thickness and blood collection. At the slaughterhouse, carcass weight, dressing percentage, back fat thickness, muscle depth, and lean meat percentage were recorded. Data were analysed using ANOVA, with the pen as the experimental unit. Diets BG1 or BG2 did not affect the performance of the pigs, except for a significant decrease in the ADG of the pigs fed the BG2 diet in the feeding period of 50-80 kg. However, no differences in performance were observed in the overall experimental period. Faecal scores, carcass quality, and serum levels of urea, insulin, and leptin were also not affected by the diet. In summary, leftovers (stems and leaves) of BG can be successfully added to the diet of growing-finishing pigs without interfering with performance and carcass characteristics.
Collapse
Affiliation(s)
- Xiaonan Guan
- Department of Research & Development, Schothorst Feed Research, 8200 AM Lelystad, The Netherlands
| | - Regiane R Santos
- Department of Research & Development, Schothorst Feed Research, 8200 AM Lelystad, The Netherlands
| | - Sietse J Koopmans
- Wageningen Livestock Research, Wageningen University & Research, 6700 AH Wageningen, The Netherlands
| | - Francesc Molist
- Department of Research & Development, Schothorst Feed Research, 8200 AM Lelystad, The Netherlands
| |
Collapse
|
4
|
Pouraghakouchak S, Riasi A, Mahdavi AH, Kowsar R, Sadeghi-Sefidmazgi A, Rafiee H, Zeraatkar M. Effect of tomato pomace and different ratios of linoleic acid to alpha-linolenic acid in starter diet on growth performance and blood metabolites in Holstein calves. Anim Feed Sci Technol 2022. [DOI: 10.1016/j.anifeedsci.2022.115469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
5
|
Jao J, Balmert LC, Sun S, Qiu Y, Kraus TA, Kirmse B, Sperling RS, Abrams EJ, Myer L, Arpadi S, Geffner ME, LeRoith D, Kurland IJ. Distinct cord blood C-peptide, adipokine, and lipidomic signatures by in utero HIV exposure. Pediatr Res 2022; 92:233-241. [PMID: 34446848 PMCID: PMC8881568 DOI: 10.1038/s41390-021-01705-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 07/14/2021] [Accepted: 08/08/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND Early-life metabolic derangements in HIV-exposed uninfected (HEU) infants have been reported. METHODS Pregnant women with HIV and HIV-uninfected pregnant women were enrolled with their newborns in a US cohort from 2011 to 2015. We measured cord insulin, C-peptide, and metabolic cytokines of HEU and HIV-unexposed uninfected (HUU) newborns using ELISA and metabolites, lipid subspecies, and eicosanoids via liquid chromatography/mass spectrometry. Linear regression was employed to assess the association of intrauterine HIV/ART with insulin and C-peptide. Graphical lasso regression was used to identify differences between metabolite/lipid subspecies networks associated with C-peptide. RESULTS Of 118 infants, 56 were HEU, ART exposed. In adjusted analyses, mean cord insulin (β = 0.295, p = 0.03) and C-peptide (β = 0.522, p < 0.01) were significantly higher in HEU vs. HUU newborns. HEU neonates exhibited primarily positive associations between complex lipids and C-peptide, indicative of fuel storage, and augmented associations between cord eicosanoids and cytokines. HUU neonates exhibited negative associations with lipids and C-peptide indicative of increased fuel utilization. CONCLUSION Higher cord insulin and C-peptide in HEU vs. HUU newborns as well as differences in cord metabolites, metabolic-related cytokines, and eicosanoids may reflect a propensity for fuel storage and an inflammatory milieu suggestive of fetal metabolic changes associated with in utero HIV/ART exposure. IMPACT There is a paucity of studies assessing cord blood and neonatal metabolic health in HIV-exposed uninfected (HEU) newborns, an increasing population worldwide. Compared to HIV-unexposed uninfected (HUU) newborns, HEU newborns exhibit alterations in fuel homeostasis and an inflammatory milieu associated with in utero HIV/antiretroviral therapy (ART) exposure. The long-term implications of these neonatal findings are as yet unknown, but merit continued evaluation as this important and growing population ages into adulthood.
Collapse
Affiliation(s)
- Jennifer Jao
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Department of Medicine, Division of Adult Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Lauren C. Balmert
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA, Department of Preventive Medicine, Division of Biostatistics
| | - Shan Sun
- Ann and Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL, USA, Department of Pediatrics, Division of Pediatric Infectious Diseases
| | - Yunping Qiu
- Albert Einstein College of Medicine, Bronx, NY, USA, Department of Medicine, Division of Endocrinology, Fleischer Institute for Diabetes and Metabolism
| | - Thomas A. Kraus
- Icahn School of Medicine at Mount Sinai, New York, NY, USA, Center for Therapeutic Antibody Development
| | - Brian Kirmse
- University of Mississippi Medical Center, Jackson, MS, USA, Department of Medical Genetics
| | - Rhoda S. Sperling
- Icahn School of Medicine at Mount Sinai, New York, NY, USA, Department of Obstetrics, Gynecology, and Reproductive Health
| | - Elaine J. Abrams
- ICAP at Columbia, Mailman School of Public Health and Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA,Vagelos College of Physicians & Surgeons and Mailman School of Public Health, Columbia University, New York, NY, USA, G.H. Sergievsky Center, Department of Pediatrics, Department of Epidemiology
| | - Landon Myer
- University of Cape Town, Cape Town, South Africa, School of Public Health & Family Medicine, Faculty of Health Sciences, Division of Epidemiology & Biostatistics
| | - Stephen Arpadi
- University of Cape Town, Cape Town, South Africa, School of Public Health & Family Medicine, Faculty of Health Sciences, Division of Epidemiology & Biostatistics
| | - Mitchell E. Geffner
- Keck School of Medicine of USC, Los Angeles, CA, USA, The Saban Research Institute of Children’s Hospital Los Angeles
| | - Derek LeRoith
- Icahn School of Medicine at Mount Sinai, New York, NY, USA, Department of Medicine, Division of Endocrinology, Diabetes and Bone Diseases
| | - Irwin J. Kurland
- Albert Einstein College of Medicine, Bronx, NY, USA, Department of Medicine, Division of Endocrinology, Fleischer Institute for Diabetes and Metabolism
| |
Collapse
|
6
|
Zem Fraga A, Louveau I, Campos PHRF, Hauschild L, Le Floc'h N. Selection for feed efficiency elicits different postprandial plasma metabolite profiles in response to poor hygiene of housing conditions in growing pigs. PLoS One 2021; 16:e0246216. [PMID: 33780478 PMCID: PMC8006997 DOI: 10.1371/journal.pone.0246216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/15/2021] [Indexed: 11/18/2022] Open
Abstract
This study was conducted to compare postprandial plasma concentrations of insulin, energy-related metabolites, and amino acids measured after a 6-week challenge consisting of exposure to good or poor hygiene of housing conditions of 24 growing pigs divergently selected for low-RFI (LRFI) and high-RFI (HRFI). Blood indicators of immune responses were assessed from samples collected before 0 (W0), and 3 (W3), and 6 weeks (W6) after pigs transfer to their respective hygiene of housing conditions. Plasma haptoglobin concentrations and blood neutrophil granulocyte numbers were greater in poor than in good hygiene of housing conditions at W3. Plasma concentrations of total immunoglobulin G were greater (p = 0.04) in poor than in good hygiene of housing conditions at W6. At W6, pigs were fitted with an intravenous catheter for serial blood samplings. Low-RFI pigs had greater insulin (p < 0.001) and lower triglyceride (p = 0.04) average plasma concentrations than HRFI pigs in both conditions. In poor hygiene of housing conditions, the peaks of insulin and glucose were observed earlier and that of insulin was greater in LRFI than in HRFI pigs. Irrespective of genetic line, average plasma concentrations of histidine, isoleucine, leucine, methionine, threonine, valine, and alanine were greater in poor compared with good hygiene of housing conditions. Only HRFI pigs had greater lysine, asparagine, proline, and tyrosine plasma concentrations in poor than in good hygiene of housing conditions. Conversely, arginine, tryptophan, proline, and tyrosine plasma concentrations were lower only for LRFI pigs housed in poor hygiene conditions. Our results suggest that, contrary to HRFI, LRFI pigs increase or maintain their utilization of tryptophan, arginine, and lysine when housed in poor hygiene conditions. This indicates that this difference may contribute to the better capacity of LRFI to cope with poor hygiene of housing conditions.
Collapse
Affiliation(s)
- Alícia Zem Fraga
- Department of Animal Science, School of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, Brazil
- PEGASE, INRAE, Institut Agro, Saint Gilles, France
| | | | | | - Luciano Hauschild
- Department of Animal Science, School of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, Brazil
| | | |
Collapse
|
7
|
Lachica M, Rojas-Cano M, Lara L, Haro A, Fernández-Fígares I. Net portal appearance of proteinogenic amino acids in Iberian pigs fed betaine and conjugated linoleic acid supplemented diets. Anim Feed Sci Technol 2021. [DOI: 10.1016/j.anifeedsci.2021.114825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
8
|
Nagyová V, Tóthová C, Nagy O. The impact of colostrum intake on the serum protein electrophoretic pattern in newborn ruminants. JOURNAL OF APPLIED ANIMAL RESEARCH 2016. [DOI: 10.1080/09712119.2016.1218886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Veronika Nagyová
- Clinic for Ruminants, University of Veterinary Medicine and Pharmacy, Košice, Slovak Republic
| | - Csilla Tóthová
- Clinic for Ruminants, University of Veterinary Medicine and Pharmacy, Košice, Slovak Republic
| | - Oskar Nagy
- Clinic for Ruminants, University of Veterinary Medicine and Pharmacy, Košice, Slovak Republic
| |
Collapse
|
9
|
Nutritional regulation of the anabolic fate of amino acids within the liver in mammals: concepts arising from in vivo studies. Nutr Res Rev 2016; 28:22-41. [PMID: 26156215 DOI: 10.1017/s0954422415000013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
At the crossroad between nutrient supply and requirements, the liver plays a central role in partitioning nitrogenous nutrients among tissues. The present review examines the utilisation of amino acids (AA) within the liver in various physiopathological states in mammals and how the fates of AA are regulated. AA uptake by the liver is generally driven by the net portal appearance of AA. This coordination is lost when demands by peripheral tissues is important (rapid growth or lactation), or when certain metabolic pathways within the liver become a priority (synthesis of acute-phase proteins). Data obtained in various species have shown that oxidation of AA and export protein synthesis usually responds to nutrient supply. Gluconeogenesis from AA is less dependent on hepatic delivery and the nature of nutrients supplied, and hormones like insulin are involved in the regulatory processes. Gluconeogenesis is regulated by nutritional factors very differently between mammals (glucose absorbed from the diet is important in single-stomached animals, while in carnivores, glucose from endogenous origin is key). The underlying mechanisms explaining how the liver adapts its AA utilisation to the body requirements are complex. The highly adaptable hepatic metabolism must be capable to deal with the various nutritional/physiological challenges that mammals have to face to maintain homeostasis. Whereas the liver responds generally to nutritional parameters in various physiological states occurring throughout life, other complex signalling pathways at systemic and tissue level (hormones, cytokines, nutrients, etc.) are involved additionally in specific physiological/nutritional states to prioritise certain metabolic pathways (pathological states or when nutritional requirements are uncovered).
Collapse
|
10
|
Tóthová C, Nagy O, Kováč G. Changes in the Concentrations of Serum Protein Fractions in Calves with Age and Nutrition. ITALIAN JOURNAL OF ANIMAL SCIENCE 2016. [DOI: 10.4081/ijas.2014.2993] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
11
|
Tóthová C, Nagy O, Kováč G, Nagyová V. Changes in the concentrations of serum proteins in calves during the first month of life. JOURNAL OF APPLIED ANIMAL RESEARCH 2015. [DOI: 10.1080/09712119.2015.1031791] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
12
|
Changes in the serum protein electrophoretic pattern in lambs during the first month of life. ACTA VET BRNO 2014. [DOI: 10.2754/avb201483030187] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Studies of the changes in serum protein pattern in the neonatal period in animals are still limited. Therefore, the objective of this study was to evaluate the changes in the concentrations of serum protein fractions in 7 clinically healthy merino lambs (4 males, 3 females) during their first month of life. The first blood sampling was performed before the colostrum intake and then at 1, 2, 7, 14 and 30 days of age. Blood serum was analysed for total serum protein concentrations and for the relative and absolute values of serum protein fractions - albumin, alpha1- (α1), alpha2- (α2), beta- (β), and gamma- (γ) globulins. The results showed a significant effect of age on the serum total protein concentrations and for all the protein fractions. The concentrations of total proteins and γ-globulins increased significantly 1 day after the colostrum intake (P < 0.001); then decreased gradually till the end of the 1st month. An opposite trend was observed in the concentrations of albumin. A significant decrease of values was found 1 day after the intake of colostrum (P < 0.001) with a subsequent progressive increase of values till the end of the evaluated period. The relative concentrations of α1-globulins significantly decreased during the first month of life (P < 0.001). On the other hand, the relative values of α2- and β-globulins increased significantly from birth till the end of the monitored period (P < 0.001). Our results suggest that the serum protein electrophoretic pattern in growing lambs is significantly influenced by the age of the evaluated animal, and this should be taken into consideration when interpreting the serum protein profile. Our findings extend existing knowledge about significant changes in the protein profile associated with the physiological adaptation process in the neonatal period in young animals.
Collapse
|
13
|
Guggeri D, Meikle A, Carriquiry M, Montossi F, De Barbieri I, Viñoles C. Effect of different management systems on growth, endocrine parameters and puberty in Hereford female calves grazing Campos grassland. Livest Sci 2014. [DOI: 10.1016/j.livsci.2014.06.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
14
|
Le Naou T, Le Floc'h N, Louveau I, van Milgen J, Gondret F. Meal frequency changes the basal and time-course profiles of plasma nutrient concentrations and affects feed efficiency in young growing pigs1. J Anim Sci 2014; 92:2008-16. [DOI: 10.2527/jas.2013-7505] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- T. Le Naou
- INRA, UMR1348 Pegase, Saint-Gilles, France
- Agrocampus-Ouest, UMR1348 Pegase, Rennes, France
| | - N. Le Floc'h
- INRA, UMR1348 Pegase, Saint-Gilles, France
- Agrocampus-Ouest, UMR1348 Pegase, Rennes, France
| | - I. Louveau
- INRA, UMR1348 Pegase, Saint-Gilles, France
- Agrocampus-Ouest, UMR1348 Pegase, Rennes, France
| | - J. van Milgen
- INRA, UMR1348 Pegase, Saint-Gilles, France
- Agrocampus-Ouest, UMR1348 Pegase, Rennes, France
| | - F. Gondret
- INRA, UMR1348 Pegase, Saint-Gilles, France
- Agrocampus-Ouest, UMR1348 Pegase, Rennes, France
| |
Collapse
|
15
|
Chowdhury P, Long A, Harris G, Soulsby ME, Dobretsov M. Animal model of simulated microgravity: a comparative study of hindlimb unloading via tail versus pelvic suspension. Physiol Rep 2013; 1:e00012. [PMID: 24303103 PMCID: PMC3831940 DOI: 10.1002/phy2.12] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/04/2013] [Accepted: 05/20/2013] [Indexed: 12/21/2022] Open
Abstract
The aim of this study was to compare physiological effects of hindlimb suspension (HLS) in tail- and pelvic-HLS rat models to determine if severe stretch in the tail-HLS rats lumbosacral skeleton may contribute to the changes traditionally attributed to simulated microgravity and musculoskeletal disuse in the tail-HLS model. Adult male Sprague-Dawley rats divided into suspended and control-nonsuspended groups were subjected to two separate methods of suspension and maintained with regular food and water for 2 weeks. Body weights, food and water consumption, soleus muscle weight, tibial bone mineral density, random plasma insulin, and hindlimb pain on pressure threshold (PPT) were measured. X-ray analysis demonstrated severe lordosis in tail- but not pelvic-HLS animals. However, growth retardation, food consumption, and soleus muscle weight and tibial bone density (decreased relative to control) did not differ between two HLS models. Furthermore, HLS rats developed similar levels of insulinopenia and mechanical hyperalgesia (decreased PPT) in both tail- and pelvic-HLS groups. In the rat-to-rat comparisons, the growth retardation and the decreased PPT observed in HLS-rats was most associated with insulinopenia. In conclusion, these data suggest that HLS results in mild prediabetic state with some signs of pressure hyperalgesia, but lumbosacral skeleton stretch plays little role, if any, in these pathological changes.
Collapse
Affiliation(s)
- Parimal Chowdhury
- Department of Physiology and Biophysics, University of Arkansas for Medical SciencesLittle Rock, Arkansas, 72205
| | - Ashley Long
- Department of Physiology and Biophysics, University of Arkansas for Medical SciencesLittle Rock, Arkansas, 72205
| | - Gabrielle Harris
- Department of Physiology and Biophysics, University of Arkansas for Medical SciencesLittle Rock, Arkansas, 72205
| | - Michael E Soulsby
- Department of Physiology and Biophysics, University of Arkansas for Medical SciencesLittle Rock, Arkansas, 72205
| | - Maxim Dobretsov
- Department of Anesthesiology, University of Arkansas for Medical SciencesLittle Rock, Arkansas, 72205
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical SciencesLittle Rock, Arkansas, 72205
| |
Collapse
|
16
|
Regulation of glucose and protein metabolism in growing steers by long-chain n-3 fatty acids in muscle membrane phospholipids is dose-dependent. Animal 2012; 4:89-101. [PMID: 22443622 DOI: 10.1017/s1751731109991042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A previous study showed that long-chain n-3 polyunsaturated fatty acids (LCn-3PUFA; >18 carbons n-3) exert an anabolic effect on protein metabolism through the upregulation of insulin sensitivity and activation of the insulin signaling pathway. This study further delineates for the first time whether the anabolic effect of LCn-3PUFA on metabolism is dose responsive. Six steers were used to test three graded amounts of menhaden oil rich in LCn-3PUFA (0%, 2% and 4%; enteral infusions) according to a double 3 × 3 Latin square design. Treatment comparisons were made using iso-energetic substitutions of control oil for menhaden oil and using 6-week experimental periods. The LCn-3PUFA in muscle total membrane phospholipids increased from 8%, 14% to 20% as dietary menhaden oil increased. Feeding graded amounts of menhaden oil linearly decreased plasma insulin concentration (49, 35 and 25 μU/ml, P = 0.01). The insulin-stimulated amino acid disposal rates as assessed using hyperinsulinemic-euglycemic-euaminoacidemic clamps (20, 40 and 80 mU/kg per h) were linearly increased by the incremental administrations of menhaden oil from 169, 238 to 375 μmol/kg per h (P = 0.005) during the 40 mU/kg per h clamp, and from 295, 360 and 590 μmol/kg per h (P = 0.02) during the 80 mU/kg per h clamp. Glucose disposal rate responded according to a quadratic relationship with the incremental menhaden oil amounts (P < 0.05). A regression analysis showed that 47% of the amino acid disposal rates elicited during the hyperinsulinemic clamp was related to muscle membrane LCn-3PUFA content (P = 0.003). These results show for the first time that both protein and glucose metabolism respond in a dose-dependent manner to menhaden oil and to muscle membrane LCn-3PUFA.
Collapse
|
17
|
Brown LD, Rozance PJ, Thorn SR, Friedman JE, Hay WW. Acute supplementation of amino acids increases net protein accretion in IUGR fetal sheep. Am J Physiol Endocrinol Metab 2012; 303:E352-64. [PMID: 22649066 PMCID: PMC3423121 DOI: 10.1152/ajpendo.00059.2012] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Placental insufficiency decreases fetal amino acid uptake from the placenta, plasma insulin concentrations, and protein accretion, thus compromising normal fetal growth trajectory. We tested whether acute supplementation of amino acids or insulin into the fetus with intrauterine growth restriction (IUGR) would increase net fetal protein accretion rates. Late-gestation IUGR and control (CON) fetal sheep received acute, 3-h infusions of amino acids (with euinsulinemia), insulin (with euglycemia and euaminoacidemia), or saline. Fetal leucine metabolism was measured under steady-state conditions followed by a fetal muscle biopsy to quantify insulin signaling. In CON, increasing amino acid delivery rates to the fetus by 100% increased leucine oxidation rates by 100%. In IUGR, amino acid infusion completely suppressed fetal protein breakdown rates but increased leucine oxidation rate by only 25%, resulting in increased protein accretion rates by 150%. Acute insulin infusion, however, had very little effect on amino acid delivery rates, fetal leucine disposal rates, or fetal protein accretion rates in CON or IUGR fetuses despite robust signaling of the fetal skeletal muscle insulin-signaling cascade. These results indicate that, when amino acids are given directly into the fetal circulation independently of changes in insulin concentrations, IUGR fetal sheep have suppressed protein breakdown rates, thus increasing net fetal protein accretion.
Collapse
Affiliation(s)
- Laura D Brown
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA.
| | | | | | | | | |
Collapse
|
18
|
El-Kadi SW, Suryawan A, Gazzaneo MC, Srivastava N, Orellana RA, Nguyen HV, Lobley GE, Davis TA. Anabolic signaling and protein deposition are enhanced by intermittent compared with continuous feeding in skeletal muscle of neonates. Am J Physiol Endocrinol Metab 2012; 302:E674-86. [PMID: 22215651 PMCID: PMC3311296 DOI: 10.1152/ajpendo.00516.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Orogastric tube feeding is indicated for neonates with impaired ability to ingest and can be administered by intermittent bolus or continuous schedule. Our aim was to determine whether feeding modalities affect muscle protein deposition and to identify mechanisms involved. Neonatal pigs were overnight fasted (FAS) or fed the same amount of food continuously (CON) or intermittently (INT; 7 × 4 h meals) for 29 h. For 8 h, between hours 20 and 28, pigs were infused with [(2)H(5)]phenylalanine and [(2)H(2)]tyrosine, and amino acid (AA) net balances were measured across the hindquarters. Insulin, branched-chain AA, phenylalanine, and tyrosine arterial concentrations and whole body phenylalanine and tyrosine fluxes were greater for INT after the meal than for CON or FAS. The activation of signaling proteins leading to initiation of mRNA translation, including eukaryotic initiation factor (eIF)4E·eIF4G complex formation in muscle, was enhanced by INT compared with CON feeding or FAS. Signaling proteins of protein degradation were not affected by feeding modalities except for microtubule-associated protein light chain 3-II, which was highest in the FAS. Across the hindquarters, AA net removal increased for INT but not for CON or FAS, with protein deposition greater for INT. This was because protein synthesis increased following feeding for INT but remained unchanged for CON and FAS, whereas there was no change in protein degradation across any dietary treatment. These results suggest that muscle protein accretion in neonates is enhanced with intermittent bolus to a greater extent than continuous feeding, mainly by increased protein synthesis.
Collapse
Affiliation(s)
- Samer W El-Kadi
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Seiliez I, Panserat S, Skiba-Cassy S, Polakof S. Effect of acute and chronic insulin administrations on major factors involved in the control of muscle protein turnover in rainbow trout (Oncorhynchus mykiss). Gen Comp Endocrinol 2011; 172:363-70. [PMID: 21463630 DOI: 10.1016/j.ygcen.2011.03.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 03/24/2011] [Accepted: 03/26/2011] [Indexed: 12/28/2022]
Abstract
In this study, the effect of acute and chronic insulin treatments on major factors involved in the control of muscle protein turnover were investigated in rainbow trout (Oncorhynchus mykiss). We found that acute but not chronic insulin administration leads to the induction of the phosphorylation of several key factors (IRS1, TOR and 4E-BP1) involved in the control of the protein synthesis and to the concomitant down-regulation of the expression of ubiquitin-proteasome-related genes (atrogin1, C2, C9) and the calpains inhibitor calpastatin. In contrast, no modification of autophagy-related gene (LC3B, gabarpl1, atg4b) expressions was observed suggesting that the mechanisms controlling this proteolytic route have diverged throughout the evolution. Overall, these results provide a possible explanation of the growth-promoting properties of insulin previously described in fish and indicate that this hormone acutely administrated is able to exert a regulatory influence on various factors associated with growth in skeletal muscle.
Collapse
Affiliation(s)
- Iban Seiliez
- INRA, UR1067 Nutrition Métabolisme et Aquaculture, Saint-Pée-sur-Nivelle, France.
| | | | | | | |
Collapse
|
20
|
Yin Y, Huang R, Li T, Ruan Z, Xie M, Deng Z, Hou Y, Wu G. Amino acid metabolism in the portal-drained viscera of young pigs: effects of dietary supplementation with chitosan and pea hull. Amino Acids 2010; 39:1581-7. [PMID: 20361217 DOI: 10.1007/s00726-010-0577-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 03/18/2010] [Indexed: 01/02/2023]
Abstract
Recent studies indicate extensive catabolism of amino acids (AA) by the portal-drained viscera (PDV) of pigs and humans. Because of ethical concerns over invasive surgical procedures on infants or adults, in vivo investigations are often performed with the pig which is both an agriculturally important livestock species and a widely used animal model for nutritional and physiological studies in humans. Here, we described a new technique for implanting chronic catheters into the portal vein, ileal mesenteric vein, and carotid artery to study AA metabolism in the PDV of young pigs. This method allowed for the reduction of surgery time by 1 h and measurements of the entry of dietary AA into the portal circulation. Using such an approach, we found that dietary supplementation with 100 mg/kg chitosan (a prebiotic and a polysaccharide not digested by animal cells) reduced oxygen consumption, as well as the net absorption of dietary AA into the portal vein, thereby enhancing their bioavailability for extraintestinal tissues. In contrast, opposite results were obtained with dietary supplementation of 12% pea-hull (containing 95% of fermentable nonstarch polysaccharide). Thus, this improved technique is useful to quantify in vivo absorption and metabolism of dietary AA in young pigs.
Collapse
Affiliation(s)
- Yulong Yin
- Hunan Engineering and Research Center of Animal and Poultry Science, Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China.
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Hou Y, Wang L, Ding B, Liu Y, Zhu H, Liu J, Li Y, Wu X, Yin Y, Wu G. Dietary α-ketoglutarate supplementation ameliorates intestinal injury in lipopolysaccharide-challenged piglets. Amino Acids 2010; 39:555-64. [DOI: 10.1007/s00726-010-0473-y] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 01/04/2010] [Indexed: 12/27/2022]
|
22
|
Digestion rate of dietary starch affects systemic circulation of amino acids in weaned pigs. Br J Nutr 2010; 103:1404-12. [DOI: 10.1017/s0007114509993321] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The present study was conducted to evaluate the in vitro and in vivo digestibility of dietary starch and its digestive behaviour on the systemic circulating amino acids (AA) in weaned pigs. Eighteen weanling pigs surgically fitted with a catheter in the jugular vein were randomly assigned to three dietary treatment groups. Sticky rice starch (SRS) was hydrolysed more quickly in vitro (P < 0·05) than maize starch (MS) and resistant starch (RS), and was almost completely hydrolysed within 4 h. The in vivo digestibility of dietary starch in different segments of the small intestine was significantly different. SRS was digested (81·9 %; P < 0·05) in the anterior jejunum, but not more than half of the MS and RS was digested in the same segment of the small intestine. The digestibilities of isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, valine, alanine, aspartate and serine in the SRS group were higher than in the MS group (P < 0·05), and all nutritionally indispensable and dispensable AA in the SRS group were higher when compared with those in the RS group (P < 0·05). The serum concentrations of nutritionally indispensable AA, proline and serine in the three groups were increased to a peak point within 1·5 h postprandially then decreased gradually; however, the time that serum concentrations of alanine, aspartate, glutamate and glycine in each group increased to a peak point was different. The concentrations of nutritionally indispensable AA, including arginine, cystine, histidine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, tyrosine and valine at 09.30 hours and arginine, cystine, histidine, isoleucine, methionine, phenylalanine, threonine, tryptophan, tyrosine and valine at 13.30 hours in the SRS group were higher than in the MS group (P < 0·05); all nutritionally indispensable AA in the SRS group were higher than in the RS group at 09.30 and 13.30 hours (P < 0·05), respectively. We conclude that dietary starches digested rapidly in vitro have higher digestibility in the anterior small intestine of pigs. Diets containing rapidly digestible starch ameliorate the digestive and absorptive function and regulate AA metabolism to beneficially increase the entry of dietary AA into the systemic circulation in pigs.
Collapse
|
23
|
A mechanistic model of nutritional control of protein synthesis in animal tissues. J Theor Biol 2010; 262:361-9. [DOI: 10.1016/j.jtbi.2009.09.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/24/2009] [Accepted: 09/29/2009] [Indexed: 12/31/2022]
|
24
|
Brown LD, Rozance PJ, Barry JS, Friedman JE, Hay WW. Insulin is required for amino acid stimulation of dual pathways for translational control in skeletal muscle in the late-gestation ovine fetus. Am J Physiol Endocrinol Metab 2009; 296:E56-63. [PMID: 18940943 PMCID: PMC2636989 DOI: 10.1152/ajpendo.90310.2008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During late gestation, amino acids and insulin promote skeletal muscle protein synthesis. However, the independent effects of amino acids and insulin on the regulation of mRNA translation initiation in the fetus are relatively unknown. The purpose of this study was to determine whether acute amino acid infusion in the late-gestation ovine fetus, with and without a simultaneous increase in fetal insulin concentration, activates translation initiation pathway(s) in skeletal muscle. Fetuses received saline (C), mixed amino acid infusion plus somatostatin infusion to suppress amino acid-stimulated fetal insulin secretion (AA+S), mixed amino acid infusion with concomitant physiological increase in fetal insulin (AA), or high-dose insulin infusion with euglycemia and euaminoacidemia (HI). After a 2-h infusion period, fetal skeletal muscle was harvested under in vivo steady-state conditions and frozen for quantification of proteins both upstream and downstream of mammalian target of rapamycin (mTOR). In the AA group, we found a threefold increase in ribosomal protein S6 kinase (p70(S6k)) and Erk1/2 phosphorylation; however, blocking the physiological rise in insulin with somatostatin in the AA+S group prevented this increase. In the HI group, Akt, Erk1/2, p70(S6k), and ribosomal protein S6 were highly phosphorylated and 4E-binding protein 1 (4E-BP1) associated with eukaryotic initiation factor (eIF)4E decreased by 30%. These data show that insulin is a significant regulator of intermediates involved in translation initiation in ovine fetal skeletal muscle. Furthermore, the effect of amino acids is dependent on a concomitant increase in fetal insulin concentrations, because amino acid infusion upregulates p70(S6k) and Erk only when amino acid-stimulated increase in insulin occurs.
Collapse
Affiliation(s)
- Laura D Brown
- UCD Perinatal Research Center, F441, 13243 East 23rd Ave., PO Box 6508, Aurora, CO 80045, USA.
| | | | | | | | | |
Collapse
|
25
|
Wilson FA, Suryawan A, Orellana RA, Nguyen HV, Jeyapalan AS, Gazzaneo MC, Davis TA. Fed levels of amino acids are required for the somatotropin-induced increase in muscle protein synthesis. Am J Physiol Endocrinol Metab 2008; 295:E876-83. [PMID: 18682537 PMCID: PMC3774258 DOI: 10.1152/ajpendo.90423.2008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chronic somatotropin (pST) treatment in pigs increases muscle protein synthesis and circulating insulin, a known promoter of protein synthesis. Previously, we showed that the pST-mediated rise in insulin could not account for the pST-induced increase in muscle protein synthesis when amino acids were maintained at fasting levels. This study aimed to determine whether the pST-induced increase in insulin promotes skeletal muscle protein synthesis when amino acids are provided at fed levels and whether the response is associated with enhanced translation initiation factor activation. Growing pigs were treated with pST (0 or 180 microg x kg(-1) x day(-1)) for 7 days, and then pancreatic-glucose-amino acid clamps were performed. Amino acids were raised to fed levels in the presence of either fasted or fed insulin concentrations; glucose was maintained at fasting throughout. Muscle protein synthesis was increased by pST treatment and by amino acids (with or without insulin) (P<0.001). In pST-treated pigs, fed, but not fasting, amino acid concentrations further increased muscle protein synthesis rates irrespective of insulin level (P<0.02). Fed amino acids, with or without raised insulin concentrations, increased the phosphorylation of S6 kinase (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1), decreased inactive 4EBP1.eIF4E complex association, and increased active eIF4E.eIF4G complex formation (P<0.02). pST treatment did not alter translation initiation factor activation. We conclude that the pST-induced stimulation of muscle protein synthesis requires fed amino acid levels, but not fed insulin levels. However, under the current conditions, the response to amino acids is not mediated by the activation of translation initiation factors that regulate mRNA binding to the ribosomal complex.
Collapse
Affiliation(s)
- Fiona A Wilson
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
Thivierge MC, Bush JA, Suryawan A, Nguyen HV, Orellana RA, Burrin DG, Jahoor F, Davis TA. Positive net movements of amino acids in the hindlimb after overnight food deprivation contribute to sustaining the elevated anabolism of neonatal pigs. J Appl Physiol (1985) 2008; 105:1959-66. [PMID: 18801965 DOI: 10.1152/japplphysiol.90352.2008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During the neonatal period, high protein breakdown rate is a metabolic process inherent to elevated rates of protein accretion in skeletal muscle. To determine the relationship between hindlimb net movements of essential and nonessential amino acids in the regulation of hindlimb protein breakdown during an overnight fasting-feeding cycle, we infused overnight-food-deprived 10- and 28-day-old piglets with [1-(13)C]phenylalanine and [ring-(2)H(4)]tyrosine over 7 h (during 3 h of fasting and then during 4 h of feeding). Extraction rates for aspartate and glutamate after an overnight fast were 15% and 51% in the 10-day-old compared with 6% and 25% in the 28-day-old (P < 0.05) piglets, suggesting an altered requirement for precursors of amino acids to shuttle nitrogen to the liver as early life progresses. This occurred simultaneously with marginal positive hindlimb net balance of essential amino acids after an overnight fast, with negative net release of many nonessential amino acids, such as alanine, asparagine, glutamine, glycine, and proline. This suggests that newborn muscle does not undergo significant protein mobilization after a short period of fasting in support of an elevated rate of protein accretion. Furthermore, tyrosine efflux from hindlimb breakdown between overnight fasting and feeding periods was not different in the 10-day-old piglets, for which tyrosine was limiting, but when tyrosine supply balanced requirements in the 28-day-old piglet, hindlimb efflux was increased (P = 0.01). The results of the present study indicate that proteolysis and net movements of amino acids are coordinated mechanisms that sustain the elevated rate of net protein accretion during overnight feeding-fasting cycles in the neonate.
Collapse
Affiliation(s)
- M Carole Thivierge
- Rowett Institute of Nutrition and Health, Greenburn Rd., Bucksburn, Aberdeen AB21 9SB, UK.
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Dietary supplementation with Astragalus polysaccharide enhances ileal digestibilities and serum concentrations of amino acids in early weaned piglets. Amino Acids 2008; 37:263-70. [DOI: 10.1007/s00726-008-0142-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 06/23/2008] [Indexed: 10/21/2022]
|
28
|
Yao K, Yin YL, Chu W, Liu Z, Deng D, Li T, Huang R, Zhang J, Tan B, Wang W, Wu G. Dietary arginine supplementation increases mTOR signaling activity in skeletal muscle of neonatal pigs. J Nutr 2008; 138:867-72. [PMID: 18424593 DOI: 10.1093/jn/138.5.867] [Citation(s) in RCA: 263] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dietary arginine supplementation increases growth of neonatal pigs, but the underlying mechanisms are unknown. This study was conducted to test the hypothesis that the arginine treatment activates translation initiation factors and protein synthesis in skeletal muscle. Piglets were fed milk-based diets supplemented with 0 or 0.6% L-arginine between 7 and 14 d of age. Following a 7-d period of arginine supplementation, at 1 h after the last meal, jugular venous blood samples were obtained for metabolite analysis, whereas longissimus muscle and liver were collected to determine the abundance and phosphorylation state of the mammalian target of the rapamycin (mTOR), ribosomal protein S6 kinase 1 (S6K1), eukaryotic initiation factor (eIF) 4E-binding protein-1 (4E-BP1), eIF4E, and eIF4G. Fractional rates of protein synthesis were measured in muscle and liver using the [(3)H]phenylalanine flooding-dose technique. Arginine supplementation increased (P < 0.05) daily gain, the plasma insulin concentration, and protein synthesis in skeletal muscle but not in liver. The arginine treatment enhanced the formation of the active eIF4E x eIF4G complex but reduced the amount of the inactive 4E-BP1 x eIF4E complex in muscle. These changes were associated with elevated levels of phosphorylated mTOR and 4E-BP1 in muscle of arginine-supplemented piglets (P < 0.05). Neither the total amounts nor phosphorylation levels of the translation initiation factors in the liver differed between control and arginine-supplemented piglets. Collectively, these results suggest that dietary arginine supplementation increases mTOR signaling activity in skeletal muscle, but not in liver, of milk-fed neonatal pigs. The findings provide a molecular mechanism for explaining the previous observation that increased circulating arginine stimulated muscle protein synthesis and promoted weight gain in neonatal pigs.
Collapse
Affiliation(s)
- Kang Yao
- Laboratory of Animal Nutrition and Health, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan 410125, PR China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Orellana RA, Jeyapalan A, Escobar J, Frank JW, Nguyen HV, Suryawan A, Davis TA. Amino acids augment muscle protein synthesis in neonatal pigs during acute endotoxemia by stimulating mTOR-dependent translation initiation. Am J Physiol Endocrinol Metab 2007; 293:E1416-25. [PMID: 17848637 DOI: 10.1152/ajpendo.00146.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In skeletal muscle of adults, sepsis reduces protein synthesis by depressing translation initiation and induces resistance to branched-chain amino acid stimulation. Normal neonates maintain a high basal muscle protein synthesis rate that is sensitive to amino acid stimulation. In the present study, we determined the effect of amino acids on protein synthesis in skeletal muscle and other tissues in septic neonates. Overnight-fasted neonatal pigs were infused with endotoxin (LPS, 0 and 10 microg.kg(-1).h(-1)), whereas glucose and insulin were maintained at fasting levels; amino acids were clamped at fasting or fed levels. In the presence of fasting insulin and amino acids, LPS reduced protein synthesis in longissimus dorsi (LD) and gastrocnemius muscles and increased protein synthesis in the diaphragm, but had no effect in masseter and heart muscles. Increasing amino acids to fed levels accelerated muscle protein synthesis in LD, gastrocnemius, masseter, and diaphragm. LPS stimulated protein synthesis in liver, lung, spleen, pancreas, and kidney in fasted animals. Raising amino acids to fed levels increased protein synthesis in liver of controls, but not LPS-treated animals. The increase in muscle protein synthesis in response to amino acids was associated with increased mTOR, 4E-BP1, and S6K1 phosphorylation and eIF4G-eIF4E association in control and LPS-infused animals. These findings suggest that amino acids stimulate skeletal muscle protein synthesis during acute endotoxemia via mTOR-dependent ribosomal assembly despite reduced basal protein synthesis rates in neonatal pigs. However, provision of amino acids does not further enhance the LPS-induced increase in liver protein synthesis.
Collapse
Affiliation(s)
- Renán A Orellana
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA.
| | | | | | | | | | | | | |
Collapse
|
30
|
Bergeron K, Julien P, Davis TA, Myre A, Thivierge MC. Long-chain n-3 fatty acids enhance neonatal insulin-regulated protein metabolism in piglets by differentially altering muscle lipid composition. J Lipid Res 2007; 48:2396-410. [PMID: 17673528 PMCID: PMC2668875 DOI: 10.1194/jlr.m700166-jlr200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
This study investigated the role of long-chain n-3 polyunsaturated fatty acids (LCn-3PUFAs) of muscle phospholipids in the regulation of neonatal metabolism. Twenty-eight piglets were weaned at 2 days of age and raised on one of two milk formulas that consisted of either a control formula supplying 0% or a formula containing 3.5% LCn-3PUFAs until 10 or 28 days of age. There was a developmental decline in the insulin sensitivity of amino acid disposal in control pigs during the first month of life, with a slope of -2.24 micromol.kg(-1).h(-1) (P = 0.01) per unit of insulin increment, as assessed using hyperinsulinemic-euglycemic-euaminoacidemic clamps. LCn-3PUFA feeding blunted this developmental decline, resulting in differing insulin sensitivities (P < 0.001). When protein metabolism was assessed under parenteral feeding-induced hyperinsulinemia, LCn-3PUFAs reduced by 16% whole body oxidative losses of amino acids (from 238 to 231 micromol.kg(-1).h(-1); P = 0.06), allowing 41% more amino acids to accrete into body proteins (from 90 to 127 micromol.kg(-1).h(-1); P = 0.06). The fractional synthetic rate of muscle mixed proteins remained unaltered by the LCn-3PUFA feeding. However, LCn-3PUFAs retarded a developmental increase in the essential-to-nonessential amino acid ratio of the muscle intracellular free pool (P = 0.05). Overall, alterations in metabolism were concomitant with a preferential incorporation of LCn-3PUFAs into muscle total membrane phospholipids (P < 0.001), in contrast to intramuscular triglycerides. These results underscore the potential role of LCn-3PUFAs as regulators of different aspects of protein metabolism in the neonate.
Collapse
Affiliation(s)
- Karen Bergeron
- Department of Animal Science, Faculty of Food Sciences and Agriculture, Laval University, Québec, Québec G1K 7P4, Canada
- Institute of Nutraceuticals and Functional Foods, Faculty of Food Sciences and Agriculture, Laval University, Québec, Québec G1K 7P4, Canada
| | - Pierre Julien
- Lipid Research Center, Laval University Hospital Center, Québec, Québec G1V 4G2, Canada
| | - Teresa A. Davis
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
| | - Alexandre Myre
- Department of Animal Science, Faculty of Food Sciences and Agriculture, Laval University, Québec, Québec G1K 7P4, Canada
- Institute of Nutraceuticals and Functional Foods, Faculty of Food Sciences and Agriculture, Laval University, Québec, Québec G1K 7P4, Canada
| | - M. Carole Thivierge
- Department of Animal Science, Faculty of Food Sciences and Agriculture, Laval University, Québec, Québec G1K 7P4, Canada
- Institute of Nutraceuticals and Functional Foods, Faculty of Food Sciences and Agriculture, Laval University, Québec, Québec G1K 7P4, Canada
- Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK
- To whom correspondence should be addressed. e-mail:
| |
Collapse
|
31
|
Jeyapalan AS, Orellana RA, Suryawan A, O'Connor PMJ, Nguyen HV, Escobar J, Frank JW, Davis TA. Glucose stimulates protein synthesis in skeletal muscle of neonatal pigs through an AMPK- and mTOR-independent process. Am J Physiol Endocrinol Metab 2007; 293:E595-603. [PMID: 17551002 DOI: 10.1152/ajpendo.00121.2007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Skeletal muscle protein synthesis is elevated in neonates in part due to an enhanced response to the rise in insulin and amino acids after eating. In vitro studies suggest that glucose plays a role in protein synthesis regulation. To determine whether glucose, independently of insulin and amino acids, is involved in the postprandial rise in skeletal muscle protein synthesis, pancreatic-substrate clamps were performed in neonatal pigs. Insulin secretion was inhibited with somatostatin and insulin was infused to reproduce fasting or fed levels, while glucose and amino acids were clamped at fasting or fed levels. Fractional protein synthesis rates and translational control mechanisms were examined. Raising glucose alone increased protein synthesis in fast-twitch glycolytic muscles but not in other tissues. The response in muscle was associated with increased phosphorylation of protein kinase B (PKB) and enhanced formation of the active eIF4E.eIF4G complex but no change in phosphorylation of AMP-activated protein kinase (AMPK), tuberous sclerosis complex 2 (TSC2), mammalian target of rapamycin (mTOR), 4E-binding protein-1 (4E-BP1), ribosomal protein S6 kinase (S6K1), or eukaryotic elongation factor 2 (eEF2). Raising glucose, insulin, and amino acids increased protein synthesis in most tissues. The response in muscle was associated with phosphorylation of PKB, mTOR, S6K1, and 4E-BP1 and enhanced eIF4E.eIF4G formation. The results suggest that the postprandial rise in glucose, independently of insulin and amino acids, stimulates protein synthesis in neonates, and this response is specific to fast-twitch glycolytic muscle and occurs by AMPK- and mTOR-independent pathways.
Collapse
Affiliation(s)
- Asumthia S Jeyapalan
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center and Pediatric Critical Care Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Wang X, Qiao S, Yin Y, Yue L, Wang Z, Wu G. A deficiency or excess of dietary threonine reduces protein synthesis in jejunum and skeletal muscle of young pigs. J Nutr 2007; 137:1442-6. [PMID: 17513404 DOI: 10.1093/jn/137.6.1442] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dietary threonine imbalance is known to reduce the growth of the small intestine, liver, and skeletal muscle in young animals, but the underlying mechanism is largely unknown. Using the pig model, this study was conducted to test the hypothesis that either a deficiency or an excess of dietary threonine impairs protein synthesis in these tissues. Young pigs (25 d of age) were fed diets containing 0.37, 0.74 (current NRC requirement) or 1.11% true ileal digestible threonine (TIDT) (n = 6/diet). Pigs receiving the 0.74 and 1.11% TIDT diets were pair-fed with the same amount of feed as pigs receiving the 0.37% TIDT diet. After a 14-d dietary treatment, the fractional synthesis rate (FSR) of protein in tissues was measured using a flooding dose of l-phenylalanine plus L-[ring-(2)H(5)]phenylalanine. The results indicated that the FSR of protein in liver was reduced (P < 0.05) in pigs fed the 0.37% TIDT diet compared with pigs fed the 0.74 or 1.11% TIDT diet, and did not differ between pigs fed the 0.74 and 1.11% TIDT diets. The FSR of protein in longissimus muscle, jejunal mucosa, and mucins was reduced (P < 0.05) in pigs fed the 0.37 or 1.11% TIDT diet compared with pigs fed the 0.74% TIDT diet. The absolute synthesis rate of protein in the jejunal mucosa and muscle was also reduced (P < 0.01) in pigs fed the 0.37 and 1.11% TIDT diets compared with the controls. The absolute synthesis rate of hepatic protein was lower (P < 0.01) in pigs fed the 0.37% TIDT diets when compared with pigs fed the 0.74% TIDT diet. Protein synthesis in skeletal muscle as well as jejunal mucosa and mucins was reduced to a greater extent than that in liver in response to an imbalance of dietary threonine. Collectively, these results indicate that either an excess or a deficiency of dietary threonine decreases protein synthesis in rapidly growing tissues of young pigs. The findings provide a mechanism for the low growth performance of animals fed a threonine-imbalanced diet.
Collapse
Affiliation(s)
- Xu Wang
- National Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | | | | | | | | | | |
Collapse
|
33
|
Debras E, Prod'homme M, Rieu I, Balage M, Dardevet D, Grizard J. Postprandial leucine deficiency failed to alter muscle protein synthesis in growing and adult rats. Nutrition 2007; 23:267-76. [PMID: 17352963 DOI: 10.1016/j.nut.2006.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 12/06/2006] [Accepted: 12/19/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE This study examined the effect of a specific acute postprandial leucine deficiency on skeletal muscle protein synthesis in growing and adult rats. Because the anabolic action of dietary leucine supplementation is controversial, except during aging, we hypothesized that the maximum leucine effect might be already achieved for a normal postprandial rise of leucine. Preventing this rise during the 1- to 3-h period after feeding may reveal the leucine regulation. METHODS On the day of the experiment, rats were fasted (postabsorptive, PA group) or fed for 1 h a control meal (postprandial, control, PP group) or a leucine-poor meal (postprandial, PP-Leu group). Muscle protein synthesis was assessed in vivo, over the 1- to 3-h period after meal distribution, using the flooding dose method (L-1-(13)C phenylalanine). RESULTS As expected, the postprandial increase in plasma free leucine was specifically abolished after feeding the leucine-poor meal, whereas all the other plasma free amino acids were roughly at normal postprandial levels. Plasma insulin increased after feeding in young rats but was constant in adult rats. Plasma insulin was similar whatever dietary leucine levels. Rates of muscle protein synthesis were stimulated by feeding in gastrocnemius and soleus muscles from young rats but only in gastrocnemius muscles from adult rats. The PP-Leu group did not differ from the control PP group regarding muscle protein synthesis. CONCLUSION The rise in plasma free leucine is not required for the stimulation of muscle protein synthesis during the 1- to 3-h period after feeding young and adult rats, as previously observed in old rats.
Collapse
Affiliation(s)
- Elisabeth Debras
- Unité de Nutrition Humaine, UMR1019, Institut National de la Recherche Agronomique, F-63122 Saint Genès Champanelle Centre de Recherche en Nutrition Humaine d'Auvergne, Auvergne, France
| | | | | | | | | | | |
Collapse
|
34
|
Frank JW, Escobar J, Nguyen HV, Jobgen SC, Jobgen WS, Davis TA, Wu G. Oral N-carbamylglutamate supplementation increases protein synthesis in skeletal muscle of piglets. J Nutr 2007; 137:315-9. [PMID: 17237304 DOI: 10.1093/jn/137.2.315] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This study investigated the potential mechanisms by which oral supplementation of N-carbamylglutamate (NCG), an analogue of endogenous N-acetylglutamate (an activator of arginine synthesis) increases growth rate in sow-reared piglets. Two piglets of equal body weight (BW) and of the same gender from each lactating sow were allotted to receive oral administration of 0 (control) or 50 mg of NCG/kg BW every 12 h for 7 d. Piglets (n=32; BW=3 kg) were studied in the food-deprived or fed state following the 7 d of treatment. Overnight food-deprived piglets were given NCG or water (control) at time 0 and 60 min. Piglets studied in the fed state were gavage-fed sow's milk with their respective NCG treatment at 0 and 60 min. At 60 min, the piglets were administered a flooding dose of [3H]phenylalanine and killed at 90 min to measure tissue protein synthesis. Piglets treated with NCG gained 28% more weight than control pigs (P<0.001) over the 7-d period. Fed pigs had greater rates of protein synthesis in longissimus dorsi and gastrocnemius muscles and duodenum compared with food-deprived pigs (P<0.001). Absolute protein synthesis rates in longissimus dorsi (P=0.050) and gastrocnemius (P=0.068) muscles were 30 and 21% greater, respectively, in NCG-treated compared with control pigs. Piglets supplemented with NCG also had greater plasma concentrations of arginine and somatotropin than control pigs (P<0.001). The results suggest that oral NCG supplementation increases plasma arginine and somatotropin levels, leading to an increase in growth rate and muscle protein synthesis in nursing piglets.
Collapse
Affiliation(s)
- Jason W Frank
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030-2600, USA.
| | | | | | | | | | | | | |
Collapse
|
35
|
Gingras AA, White PJ, Chouinard PY, Julien P, Davis TA, Dombrowski L, Couture Y, Dubreuil P, Myre A, Bergeron K, Marette A, Thivierge MC. Long-chain omega-3 fatty acids regulate bovine whole-body protein metabolism by promoting muscle insulin signalling to the Akt-mTOR-S6K1 pathway and insulin sensitivity. J Physiol 2006; 579:269-84. [PMID: 17158167 PMCID: PMC2075371 DOI: 10.1113/jphysiol.2006.121079] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The ability of the skeletal musculature to use amino acids to build or renew constitutive proteins is gradually lost with age and this is partly due to a decline in skeletal muscle insulin sensitivity. Since long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) from fish oil are known to improve insulin-mediated glucose metabolism in insulin-resistant states, their potential role in regulating insulin-mediated protein metabolism was investigated in this study. Experimental data are based on a switchback design composed of three 5 week experimental periods using six growing steers to compare the effect of a continuous abomasal infusion of LCn-3PUFA-rich menhaden oil with an iso-energetic control oil mixture. Clamp and insulin signalling observations were combined with additional data from a second cohort of six steers. We found that enteral LCn-3PUFA potentiate insulin action by increasing the insulin-stimulated whole-body disposal of amino acids from 152 to 308 micromol kg(-1) h(-1) (P=0.006). The study further showed that in the fed steady-state, chronic adaptation to LCn-3PUFA induces greater activation (P<0.05) of the Akt-mTOR-S6K1 signalling pathway. Simultaneously, whole-body total flux of phenylalanine was reduced from 87 to 67 micromol kg(-1) h(-1) (P=0.04) and oxidative metabolism was decreased (P=0.05). We conclude that chronic feeding of menhaden oil provides a novel nutritional mean to enhance insulin-sensitive aspects of protein metabolism.
Collapse
Affiliation(s)
- Andrée-Anne Gingras
- Department of animal science, Faculty of Food Sciences and Agriculture, Laval University, Quebec, QC G1K 7P4 Canada
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Marshall KM, Hurley WL, Shanks RD, Wheeler MB. Effects of suckling intensity on milk yield and piglet growth from lactation-enhanced gilts. J Anim Sci 2006; 84:2346-51. [PMID: 16908636 DOI: 10.2527/jas.2005-764] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The effects of suckling intensity on milk yield and piglet growth were determined when lactation capacity of the sow was enhanced through overexpression of a mammary-specific transgene, bovine alpha-lactalbumin. Lactational response to increased suckling stimulation was determined by fostering litters of the same age (d 1) or 7 d older (d 7) than the day of lactation to sows nontransgenic (control) or transgenic (TG) for bovine alpha-lactalbumin. Twenty first-parity gilts were allocated to 4 treatments dependent on gilt genotype and age of litter fostered (control d 1, control d 7, TG d 1, and TG d 7). Litters were standardized to 10 piglets within 24 h postpartum, and nonbirth piglets were fostered to gilts with an equal litter BW within age groups at 36 h postpartum. Milk yield was determined by the weigh-suckle-weigh method on d 6, 9, 12, 15, and 18 of lactation. Mean daily milk yield was greater (P = 0.031) for TG gilts compared with control gilts and tended to be greater (P = 0.056) for all gilts with d-7 piglets compared with those with d-1 piglets. Daily milk yield of TG d 7 gilts increased rapidly to peak at d 9 and was greater than milk yield of all control gilts at d 9 (P < 0.01), 12 (P < 0.02), and 15 (P < 0.02). Mean daily milk yield of TG d 7 gilts was 2.1 kg greater (P = 0.002) than for control d 7 gilts and 2.0 kg greater (P = 0.004) than for TG d 1 gilts. Daily milk yield of control d 1 gilts was not different from that of TG d 1 gilts (P = 0.49) or control d 7 gilts (P = 0.63). Piglet BW gain between d 3 and 6 was greater (P < 0.01) in the TG d 7 group than for all other groups and was greater (P < 0.05) than the control groups between d 6 and 9. No difference was found when comparing accumulated BW gain of the piglets between the day of age at foster (d 1 vs. 7; P = 0.606) or between the control d 1 and control d 7 groups (P = 0.759). Accumulated BW gain of piglets suckling TG d 7 gilts from d 3 through 9 was greater (P < 0.02) than that of the other groups and continued to be greater (P < 0.05) than that of either of the control groups through d 15. However, by d 15, accumulated BW gain of piglets suckling TG d 1 gilts was no longer different (P = 0.40) from that of the TG d 7 group and was greater (P < 0.05) than that of the control d 1 group. The enhanced lactation potential of these TG gilts synergized with suckling intensity to stimulate increased milk production during early lactation, resulting in increased piglet growth.
Collapse
Affiliation(s)
- K M Marshall
- University of Illinois, Department of Animal Sciences, Urbana, IL 6180, USA
| | | | | | | |
Collapse
|
37
|
Suryawan A, Escobar J, Frank JW, Nguyen HV, Davis TA. Developmental regulation of the activation of signaling components leading to translation initiation in skeletal muscle of neonatal pigs. Am J Physiol Endocrinol Metab 2006; 291:E849-59. [PMID: 16757550 DOI: 10.1152/ajpendo.00069.2006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The rapid growth of neonates is driven by high rates of skeletal muscle protein synthesis. This high rate of protein synthesis, which is induced by feeding, declines with development. Overnight-fasted 7- and 26-day-old pigs either remained fasted or were refed, and the abundance and phosphorylation of growth factor- and nutrient-induced signaling components that regulate mRNA translation initiation were measured in skeletal muscle and liver. In muscle, but not liver, the activation of inhibitors of protein synthesis, phosphatase and tensin homolog deleted on chromosome 10, protein phosphatase 2A, and tuberous sclerosis complex 1/2 increased with age. Serine/threonine phosphorylation of the insulin receptor and insulin receptor substrate-1, which downregulates insulin signaling, and the activation of AMP-activated protein kinase, an inhibitor of protein synthesis, were unaffected by age and feeding in muscle and liver. Activation of positive regulators of protein synthesis, mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase 1 (S6K1), and eIF4E-binding protein-1 (4E-BP1) decreased with age in muscle but not liver. Feeding enhanced mTOR, S6K1, and 4E-BP1 activation in muscle, and this response decreased with age. In liver, activation of S6K1 and 4E-BP1, but not mTOR, was increased by feeding but was unaffected by age. Raptor abundance and the association between raptor and mTOR were greater in 7- than in 26-day-old pigs. The results suggest that the developmental decline in skeletal muscle protein synthesis is due in part to developmental regulation of the activation of growth factor and nutrient-signaling components.
Collapse
Affiliation(s)
- Agus Suryawan
- United States Department of Agriculture/Agriculture Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA
| | | | | | | | | |
Collapse
|
38
|
Nolles JA, Van Straten EME, Bremer BI, Koopmanschap RE, Verstegen MWA, Schreurs VVAM. Dietary amino acids fed in free form and as protein components do not differently affect postprandial plasma insulin, glucagon, growth hormone and corticosterone responses in rats. J Anim Physiol Anim Nutr (Berl) 2006; 90:289-99. [PMID: 16867074 DOI: 10.1111/j.1439-0396.2005.00598.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study examined, whether the postprandial fate of dietary amino acids from different amino acid sources is regulated by the responses of insulin, glucagon, corticosterone and growth hormone (GH). Male Wistar rats were cannulated in the vena jugularis and assigned to dietary groups. The diets contained 21% casein or the same amino acids in free form. In the free amino acid diets, methionine level was varied between the groups. The feed was supplied in two distinct meals. In previous experiments it was established that oxidative amino acid losses of the free amino acid diets and protein diets were different. After 3 weeks on those diets, it appeared that the differences in postprandial oxidative losses had been diminished. GH was measured every 12 min, from 144 min before the start of the experimental meal over the following 144 min. Insulin and corticosterone were measured six times from the start of the meal until 270 min after the meal. No differences have been observed between the hormonal responses to both meals at day 5 and at day 26. In conclusion, it has been found that the differences in the oxidative losses between protein and free amino acid meals are not mediated by the combined action of the insulin, glucagon, corticosterone and GH. Postprandial catabolism of amino acids is most probably regulated by substrate induction.
Collapse
Affiliation(s)
- J A Nolles
- Human and Animal Physiology Group, Wageningen Institute of Animal Sciences (WIAS) and Research Center, Haarweg 10, NL-6709 PJ Wageningen, The Netherlands.
| | | | | | | | | | | |
Collapse
|
39
|
Rufibach K, Stefanoni N, Rey-Roethlisberger V, Schneiter P, Doherr MG, Tappy L, Blum JW. Protein Synthesis in Jejunum and Liver of Neonatal Calves Fed Vitamin A and Lactoferrin. J Dairy Sci 2006; 89:3075-86. [PMID: 16840625 DOI: 10.3168/jds.s0022-0302(06)72582-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Rates of protein synthesis (PS) and turnover are more rapid during the neonatal period than during any other stage of postnatal life. Vitamin A and lactoferrin (Lf) can stimulate PS in neonates. However, newborn calves are vitamin A deficient and have a low Lf status, but plasma vitamin A and Lf levels increase rapidly after ingestion of colostrum. Neonatal calves (n = 6 per group) were fed colostrum or a milk-based formula without or with vitamin A, Lf, or vitamin A plus Lf to study PS in the jejunum and liver. l-[(13)C]Valine was intravenously administered to determine isotopic enrichment of free (nonprotein-bound) Val (AP(Free)) in the protein precursor pool, atom percentage excess (APE) of protein-bound Val, fractional protein synthesis rate (FSR) in the jejunum and liver, and isotopic enrichment of Val in plasma (APE(Pla)) and in the CO(2) of exhaled air (APE(Ex)). The APE, AP(Free), and FSR in the jejunum and liver did not differ significantly among groups. The APE(Ex) increased, whereas APE(Pla) decreased over time, but there were no group differences. Correlations were calculated between FSR(Jej) and histomorphometrical and histochemical data of the jejunum, and between FSR(Liv) and blood metabolites. There were negative correlations between FSR(Liv) and plasma albumin concentrations and between FSR(Jej) and the ratio of villus height:crypt depth, and there was a positive correlation between FSR(Jej) and small intestinal cell proliferation in crypts. Hence, there were no effects of vitamin A and Lf and no interactions between vitamin A and Lf on intestinal and hepatic PS. However, FSR(Jej) was correlated with histomorphometrical traits of the jejunum and FSR(Liv) was correlated with plasma albumin concentrations.
Collapse
Affiliation(s)
- K Rufibach
- Division of Animal Nutrition and Physiology, Institute of Animal Genetics, Nutrition and Housing, Vetsuisse-Faculty, University of Bern, CH-3012 Bern, Switzerland
| | | | | | | | | | | | | |
Collapse
|
40
|
Orellana RA, O'Connor PMJ, Bush JA, Suryawan A, Thivierge MC, Nguyen HV, Fiorotto ML, Davis TA. Modulation of muscle protein synthesis by insulin is maintained during neonatal endotoxemia. Am J Physiol Endocrinol Metab 2006; 291:E159-66. [PMID: 16478773 DOI: 10.1152/ajpendo.00595.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sepsis promotes insulin resistance and reduces protein synthesis in skeletal muscle of adults. The effect of sepsis on insulin-stimulated muscle protein synthesis has not been determined in neonates, a highly anabolic population that is uniquely sensitive to insulin. Overnight fasted neonatal pigs were infused for 8 h with endotoxin [lipopolysaccharide (LPS), 0 and 10 mug.kg(-1).h(-1)]. Glucose and amino acids were maintained at fasting levels, insulin was clamped at either fasting or fed (2 or 10 muU/ml) levels, and fractional protein synthesis rates were determined at the end of the infusion. LPS infusion induced a septic-like state, as indicated by a sustained elevation in body temperature, heart rate, and cortisol. At fasting insulin levels, LPS reduced fractional protein synthesis rates in gastrocnemius muscle (-26%) but had no effect on the masseter and heart. By contrast, LPS stimulated liver protein synthesis (+28%). Increasing insulin to fed levels accelerated protein synthesis rates in gastrocnemius (controls by +38%, LPS by +60%), masseter (controls by +50%, LPS by +43%), heart (controls by +34%, LPS by +40%), and diaphragm (controls by +54%, LPS by +29%), and the response to insulin was similar in LPS and controls. Insulin did not alter protein synthesis in liver, kidney, or jejunum in either group. These findings suggest that acute endotoxemia lowers basal fasting muscle protein synthesis in neonates but does not alter the response of protein synthesis to insulin.
Collapse
Affiliation(s)
- Renan A Orellana
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates St., Suite 9064, Houston, TX 77030-2600, USA
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Escobar J, Frank JW, Suryawan A, Nguyen HV, Kimball SR, Jefferson LS, Davis TA. Regulation of cardiac and skeletal muscle protein synthesis by individual branched-chain amino acids in neonatal pigs. Am J Physiol Endocrinol Metab 2006; 290:E612-21. [PMID: 16278252 DOI: 10.1152/ajpendo.00402.2005] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle grows at a very rapid rate in the neonatal pig, due in part to an enhanced sensitivity of protein synthesis to the postprandial rise in amino acids. An increase in leucine alone stimulates protein synthesis in skeletal muscle of the neonatal pig; however, the effect of isoleucine and valine has not been investigated in this experimental model. The left ventricular wall of the heart grows faster than the right ventricular wall during the first 10 days of postnatal life in the pig. Therefore, the effects of individual BCAA on protein synthesis in individual skeletal muscles and in the left and right ventricular walls were examined. Fasted pigs were infused with 0 or 400 micromol x kg(-1) x h(-1) leucine, isoleucine, or valine to raise individual BCAA to fed levels. Fractional rates of protein synthesis and indexes of translation initiation were measured after 60 min. Infusion of leucine increased (P < 0.05) phosphorylation of eukaryotic initiation factor (eIF)4E-binding protein-1 and increased (P < 0.05) the amount and phosphorylation of eIF4G associated with eIF4E in longissimus dorsi and masseter muscles and in both ventricular walls. Leucine increased (P < 0.05) the phosphorylation of ribosomal protein (rp)S6 kinase and rpS6 in longissimus dorsi and masseter but not in either ventricular wall. Leucine stimulated (P < 0.05) protein synthesis in longissimus dorsi, masseter, and the left ventricular wall. Isoleucine and valine did not increase translation initiation factor activation or protein synthesis rates in skeletal or cardiac muscles. The results suggest that the postprandial rise in leucine, but not isoleucine or valine, acts as a nutrient signal to stimulate protein synthesis in cardiac and skeletal muscles of neonates by increasing eIF4E availability for eIF4F complex assembly.
Collapse
MESH Headings
- Amino Acids, Branched-Chain/blood
- Amino Acids, Branched-Chain/pharmacology
- Animals
- Animals, Newborn
- Blood Glucose/metabolism
- Blotting, Western/veterinary
- Eukaryotic Initiation Factor-4E/metabolism
- Eukaryotic Initiation Factor-4G/metabolism
- Heart Ventricles/drug effects
- Heart Ventricles/metabolism
- Insulin/blood
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Proteins/biosynthesis
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Myocardium/metabolism
- Phosphorylation
- Random Allocation
- Ribosomal Protein S6 Kinases/metabolism
- Swine/metabolism
Collapse
Affiliation(s)
- Jeffery Escobar
- United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | | | | | |
Collapse
|
42
|
Frank JW, Escobar J, Suryawan A, Nguyen HV, Kimball SR, Jefferson LS, Davis TA. Dietary protein and lactose increase translation initiation factor activation and tissue protein synthesis in neonatal pigs. Am J Physiol Endocrinol Metab 2006; 290:E225-33. [PMID: 16144813 DOI: 10.1152/ajpendo.00351.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protein synthesis and eukaryotic initiation factor (eIF) activation are increased in muscle and liver of pigs parenterally infused with amino acids and insulin. To examine the effects of enteral protein and carbohydrate on protein synthesis, pigs (n = 42, 1.7 kg body wt) were fed isocaloric milk diets containing three levels of protein (5, 15, and 25 g x kg body wt(-1) x day(-1)) and two levels of lactose (low = 11 and high = 23 g x kg body wt(-1) x day(-1)) from 1 to 6 days of age. On day 7, pigs were gavage fed after 4-h food deprivation, and tissue protein synthesis rates and biomarkers of mRNA translation were assessed. Piglet growth and protein synthesis rates in muscle and liver increased with dietary protein and plateaued at 15 g x kg body wt(-1) x day(-1) (P < 0.001). Growth tended to be greater in high-lactose-fed pigs (P = 0.07). Plasma insulin was lowest in pigs fed 5 g x kg body wt(-1) x day(-1) protein (P < 0.0001). Plasma branched-chain amino acids increased as protein intake increased (P < 0.0001). Muscle (P < 0.001) and liver (P < or = 0.001) ribosomal protein S6 kinase-1 and eIF4E-binding protein phosphorylation increased with protein intake and plateaued at 15 g x kg body wt(-1) x day(-1). The results indicate that growth and protein synthesis rates in neonatal pigs are influenced by dietary protein and lactose intake and might be mediated by plasma amino acids and insulin levels. However, feeding protein well above the piglet's requirement does not further stimulate the activation of translation initiation or protein synthesis in skeletal muscle and liver.
Collapse
Affiliation(s)
- Jason W Frank
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA
| | | | | | | | | | | | | |
Collapse
|
43
|
Frank JW, Escobar J, Suryawan A, Kimball SR, Nguyen HV, Jefferson LS, Davis TA. Protein synthesis and translation initiation factor activation in neonatal pigs fed increasing levels of dietary protein. J Nutr 2005; 135:1374-81. [PMID: 15930440 DOI: 10.1093/jn/135.6.1374] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Limited data suggest that the growth of low-birth-weight infants is enhanced by feeding a high-protein diet; however, the mechanisms involved in the effect have not been delineated. To identify these mechanisms, 34 pigs were fed from 2 to 7 d of age [60 g dry matter/(kg body weight . d)] isocaloric milk diets that contained levels of dietary protein that were marginal, adequate, and in excess of the piglets protein requirement (21, 33, and 45% of dry matter, respectively). Dietary protein replaced lactose and fat on an isocaloric basis. Fractional protein synthesis rates, various biomarkers of translational regulation, and plasma glucose and insulin levels were measured in overnight food-deprived and fed pigs. Mean daily weight gain of pigs fed the 33 and 45% protein diets was greater than that of pigs fed the 21% protein diet (P < 0.01). Plasma glucose (P = 0.07) and insulin (P < 0.01) levels decreased as dietary protein increased 60 min after feeding. Protein synthesis rates in longissimus dorsi, gastrocnemius, masseter, heart, liver, kidney, jejunum, and pancreas were greater in the fed than in the food-deprived state (P < 0.01). Protein synthesis in skeletal muscle did not change with protein intake in the fed state, but decreased quadratically (P < 0.01) with increasing dietary protein in the food-deprived state. Protein kinase B, ribosomal protein S6 kinase 1(S6K1), and eukaryotic initiation factor (eIF) 4E binding protein-1 (4E-BP1) were more phosphorylated, and assembly of the inactive eukaryotic initiation factor 4E . 4E-BP1 complex in muscle and liver was reduced in the fed state (P < 0.001) and were not consistently affected by dietary protein level. The results suggest that feeding stimulates protein synthesis, and this is modulated by the activation of initiation factors that regulate mRNA binding to the ribosomal complex. However, the provision of a high-protein diet that exceeds the protein requirement does not further enhance protein synthesis or translation initiation factor activation.
Collapse
Affiliation(s)
- Jason W Frank
- U.S. Department of Agriculture/Agriculture Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
Chapter 2 Regulation of skeletal muscle protein metabolism in growing animals. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1877-1823(09)70009-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
45
|
Prod'homme M, Balage M, Debras E, Farges MC, Kimball S, Jefferson L, Grizard J. Differential effects of insulin and dietary amino acids on muscle protein synthesis in adult and old rats. J Physiol 2004; 563:235-48. [PMID: 15513948 PMCID: PMC1665559 DOI: 10.1113/jphysiol.2004.068841] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The potential roles of insulin and dietary amino acids in the regulation of skeletal muscle protein synthesis were examined in adult and old rats. Animals were fed over 1 h with either a 25% or a 0% amino acid/protein meal. In each nutritional condition, postprandial insulin secretion was either maintained or blocked with diazoxide injections. Protein synthesis in gastrocnemius and soleus muscles was assessed in vivo using the flooding dose method. Insulin suppression decreased protein synthesis in both muscles irrespective of the nutritional condition and age of the rats. Moreover, reduced insulinaemia was associated with 4E-BP1 dephosphorylation, enhanced assembly of the 4E-BP1-eIF4E inactive complex and hypophosphorylation of eIF4E, p70S6k and protein kinase B, key intermediates in the regulation of translation initiation and protein synthesis. Old rats did not differ from adult rats. The lack of amino acids in the meal of insulin-suppressed rats did not result in any additional decrease in protein synthesis. In the presence of insulin secretion, dietary amino acid suppression significantly decreased gastrocnemius protein synthesis in adult but not in old rats. Amino acid suppression was associated with reduced phosphorylation of 4E-BP1 and p70S6k in adults. Along with protein synthesis, only the inhibition of p70S6k phosphorylation was abolished in old rats. We concluded that insulin is required for the regulation of muscle protein synthesis irrespective of age and that the effect of dietary amino acids is blunted in old rats.
Collapse
Affiliation(s)
- Magali Prod'homme
- Institut National de la Recherche Agronomique et Centre de Recherche en Nutrition Humaine d'Auvergne, Unité de Nutrition et Métabolisme Protéique, 63122 Saint Genès-Champanelle, France.
| | | | | | | | | | | | | |
Collapse
|
46
|
Gatford KL, De Blasio MJ, Thavaneswaran P, Robinson JS, McMillen IC, Owens JA. Postnatal ontogeny of glucose homeostasis and insulin action in sheep. Am J Physiol Endocrinol Metab 2004; 286:E1050-9. [PMID: 14761875 DOI: 10.1152/ajpendo.00340.2003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucose tolerance declines with maturation and aging in several species, but the time of onset and extent of changes in insulin sensitivity and insulin secretion and their contribution to changes in glucose tolerance are unclear. We therefore determined the effect of maturation on glucose tolerance, insulin secretion, and insulin sensitivity in a longitudinal study of male and female sheep from preweaning to adulthood, and whether these measures were related across age. Glucose tolerance was assessed by intravenous glucose tolerance test (IVGTT, 0.25 g glucose/kg), insulin secretion as the integrated insulin concentration during IVGTT, and insulin sensitivity by hyperinsulinemic-euglycemic clamp (2 mU insulin.kg(-1).min(-1)). Glucose tolerance, relative insulin secretion, and insulin sensitivity each decreased with age (P < 0.001). The disposition index, the product of insulin sensitivity, and various measures of insulin secretion during fasting or IVGTT also decreased with age (P < 0.001). Glucose tolerance in young adult sheep was independently predicted by insulin sensitivity (P = 0.012) and by insulin secretion relative to integrated glucose during IVGTT (P = 0.005). Relative insulin secretion before weaning was correlated positively with that in the adult (P = 0.023), whereas glucose tolerance, insulin sensitivity, and disposition indexes in the adult did not correlate with those at earlier ages. We conclude that glucose tolerance declines between the first month of life and early adulthood in the sheep, reflecting decreasing insulin sensitivity and absence of compensatory insulin secretion. Nevertheless, the capacity for insulin secretion in the adult reflects that early in life, suggesting that it is determined genetically or by persistent influences of the perinatal environment.
Collapse
Affiliation(s)
- K L Gatford
- Department of Physiology, University of Adelaide, Adelaide SA 5005, Australia
| | | | | | | | | | | |
Collapse
|
47
|
O'Connor PMJ, Kimball SR, Suryawan A, Bush JA, Nguyen HV, Jefferson LS, Davis TA. Regulation of neonatal liver protein synthesis by insulin and amino acids in pigs. Am J Physiol Endocrinol Metab 2004; 286:E994-E1003. [PMID: 14761876 DOI: 10.1152/ajpendo.00391.2003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The high efficiency of protein deposition during the neonatal period is driven by high rates of protein synthesis, which are maximally stimulated after feeding. Infusion of amino acids, but not insulin, reproduces the feeding-induced stimulation of liver protein synthesis. To determine whether amino acid-stimulated liver protein synthesis is independent of insulin in neonates, and to examine the role of amino acids and insulin in the regulation of translation initiation in neonatal liver, we performed pancreatic glucose-amino acid clamps in overnight-fasted 7-day-old pigs. Pigs (n = 9-12/group) were infused with insulin at 0, 10, 22, and 110 ng.kg(-0.66).min(-1) to achieve 0, 2, 6, and 30 microU/ml insulin, respectively. At each insulin dose, amino acids were maintained at fasting or fed levels or, in conjunction with the highest insulin dose, allowed to fall to below fasting levels. Insulin had no effect on the fractional rate of protein synthesis in liver. Amino acids increased fractional protein synthesis rates in liver at each dose of insulin, including the 0 microU/ml dose. There was a dose-response effect of amino acids on liver protein synthesis. Amino acids and insulin increased protein S6 kinase and 4E-binding protein 1 (4E-BP1) phosphorylation; however, only amino acids decreased formation of the inactive 4E-BPI.eukaryotic initiation factor-4E (eIF4E) complex. The results suggest that amino acids regulate liver protein synthesis in the neonate by modulating the availability of eIF4E for 48S ribosomal complex formation and that this response does not require insulin.
Collapse
Affiliation(s)
- Pamela M J O'Connor
- United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates St., Suite 9064, Houston, TX 77030, USA
| | | | | | | | | | | | | |
Collapse
|
48
|
Orellana RA, Kimball SR, Nguyen HV, Bush JA, Suryawan A, Thivierge MC, Jefferson LS, Davis TA. Regulation of muscle protein synthesis in neonatal pigs during prolonged endotoxemia. Pediatr Res 2004; 55:442-9. [PMID: 14681494 DOI: 10.1203/01.pdr.0000110526.02282.f3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In adults, protein synthesis in skeletal muscle is reduced by as much as 50% after a septic challenge, and is associated with repression of translation initiation. Neonates are highly anabolic and their muscle protein synthesis rates are elevated and uniquely sensitive to amino acid and insulin stimulation. In the present study, neonatal piglets were infused with Endotoxin (lipopolysaccharide, LPS) for 20 h at 0 (n = 6) and 13 microg/kg*h (n = 8). During the last 2 h, dextrose and an amino acid mixture were infused to attain fed plasma concentrations of amino acids, glucose, and insulin. Fractional protein synthesis rates and translational control mechanisms were examined. LPS reduced protein synthesis in glycolytic muscles by only 13% and had no significant effect in oxidative muscles. This depression was associated with reductions in the phosphorylation of 4E-BP1 (-31%) and S6 K1 (-78%), and a decrease in eIF4G binding to eIF4E (-62%), an event required for formation of the active mRNA binding complex. By comparison, LPS increased protein synthesis in the liver (+29%), spleen (+32%), and kidney (+27%), and in the liver, this increase was associated with augmented eIF4G to eIF4E binding (+88%). In muscle and liver, LPS did not alter eIF2B activity, an event that regulates initiator met-tRNA(i) binding to the 40S ribosomal complex. These findings suggest that during sustained endotoxemia, the high rate of neonatal muscle protein synthesis is largely maintained in the presence of substrate supply, despite profound changes in translation initiation factors that modulate the mRNA binding step in translation initiation.
Collapse
Affiliation(s)
- Renán A Orellana
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates Street, Houston, TX 77030, USA
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Suryawan A, O'Connor PMJ, Kimball SR, Bush JA, Nguyen HV, Jefferson LS, Davis TA. Amino acids do not alter the insulin-induced activation of the insulin signaling pathway in neonatal pigs. J Nutr 2004; 134:24-30. [PMID: 14704288 DOI: 10.1093/jn/134.1.24] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Feeding stimulates protein synthesis in skeletal muscle and liver of neonates and this response can be reproduced in muscle by the infusion of insulin or amino acids and in liver by the infusion of amino acids, but not insulin. Activation of insulin signaling components leading to translation initiation is associated with the feeding-induced stimulation of muscle protein synthesis in neonates. In this study, we examined the individual roles of insulin and amino acids in the activation of insulin signaling components leading to translation initiation, specifically, the insulin receptor (IR), insulin receptor substrate 1 (IRS-1), phosphatidylinositol 3-kinase (PI 3-kinase), protein kinase B (PKB) and ribosomal protein S6. Insulin secretion was blocked by somatostatin in food-deprived, 7-d-old pigs (n=8-12/group); insulin was infused to achieve plasma levels of approximately 0, 17, 52, and 255 pmol/L (approximately 0, 2, 6, 30 microU/mL), and amino acids were clamped at food-deprived or fed levels. In skeletal muscle, insulin increased the activation of IR, IRS-1, PI 3-kinase, PKB and S6 and stimulated protein synthesis. In liver, insulin increased the activation of IR, IRS-1, PI 3-kinase, PKB and S6, but had no effect on protein synthesis. Raising amino acids from the food-deprived to the fed level did not alter the insulin-induced activation of IR, IRS-1, PI 3-kinase and PKB but increased S6 phosphorylation and protein synthesis in skeletal muscle and liver. The results suggest that the stimulation of protein synthesis in muscle by insulin involves activation of insulin signaling components, and the stimulation of protein synthesis in muscle and liver by amino acids occurs by mechanisms independent of the early steps of this pathway. Furthermore, amino acids do not alter the insulin-stimulated activation of early steps in the insulin signaling pathway.
Collapse
Affiliation(s)
- Agus Suryawan
- US Department of Agriculture/Agriculture Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | | | |
Collapse
|
50
|
Otulakowski G, Rafii B, O'Brodovich H. Differential translational efficiency of ENaC subunits during lung development. Am J Respir Cell Mol Biol 2003; 30:862-70. [PMID: 14672917 DOI: 10.1165/rcmb.2003-0381oc] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The amiloride-sensitive epithelial Na(+) channel (ENaC), the rate-limiting step in epithelial Na(+) transport, consists of three subunits: alpha, beta, and gamma. The abundance of mRNA encoding the alpha-subunit far surpasses the amount for other subunits, and considerably exceeds the predicted subunit protein stoichiometry. We evaluated 5'-untranslated region (UTR) expression and found that fetal rat lung uses alternative 5'UTRs for alpha-ENaC during development. Sucrose density gradient analysis of postnuclear supernatants from fetal rat lung homogenates demonstrated that all three ENaC subunits were associated with high molecular weight polysomes, indicating active translation of the mRNAs, but translational efficiency was much lower for the alpha-subunit. Sucrose density gradient distributions were comparable for the endogenously expressed alpha-ENaC 5'UTRs in rat lung at Fetal Day 20 or Postnatal Day 1 using Northern analysis. Although birth resulted in a global decrease in lung mRNA translation, the loading of ribosomes on ENaC subunit mRNAs was largely unaffected. Evaluation of cytokeratin 18 and vimentin mRNAs in these gradients suggested a cell-specific effect. We conclude that there are different translational efficiencies for ENaC subunits and that perinatal processes globally modulate lung mRNA translation.
Collapse
Affiliation(s)
- Gail Otulakowski
- CIHR Group in Lung Development, Research Institute of the Hospital for Sick Children, Programme in Lung Biology Research, 555 University Avenue, Toronto, ON, M5G 1X8 Canada.
| | | | | |
Collapse
|