Effects of ractopamine and arginine dietary supplementation for sows on growth performance and carcass quality of their progenies

L-Arginine supplementation in pregnancy: a systematic review of maternal and fetal outcomes

BACKGROUND/AIM OF THE STUDY

L-Arginine (L-Arg)/Nitric Oxide (NO) system is involved in the pathophysiology of relevant Obstetric conditions. This review aims at summarizing the effects of L-Arg supplementation in pregnancy looking at safety and efficacy.

METHODS

We conducted a systematic review of the literature utilizing PubMed for studies published from inception to September 2022. The search included human and animal studies where L-Arg was supplemented pre-conceptionally or during pregnancy, by either oral or intravenous route. The main perinatal outcomes were focused.

RESULTS

Among 1028 publications, 51 studies were eligible for inclusion, 25 were performed in women, and the remnant in animals. Compared to controls/placebo, the supplementation with L-Arg reduced the development of pre-eclampsia (four studies), decreased blood pressure, and reduced the need for antihypertensive drugs in women with Hypertensive Disorders of Pregnancy (HDP, eight studies). In women carrying growth retarded fetuses, L-Arg improved fetoplacental circulation, birth weight and neonatal outcomes (five studies), while in the case of threatened preterm birth, L-Arg reduced uterine contractions (two studies). In several animal species, L-Arg supplementation in pregnancy improved reproductive performance by increasing the litter number and size. Moreover, in pre-eclamptic and metabolic syndrome experimental models, maternal hypertension and fetal growth were improved.

CONCLUSION

L-Arg displays biological activities in pregnancies complicated by HDP and growth restriction, both in women and animal models. L-Arg administration is safe and could be a candidate as an intervention beneficial to maternal and fetal outcomes, at least in moderate clinical disorders.

Effect of dietary arginine supplementation on protein synthesis, meat quality and flavor in growing lambs

This study aimed to assess the effect of dietary arginine supplementation on protein synthesis, meat quality and flavor in lambs. Eighteen Dorper (♂) × Small Tailed Han sheep (♀) crossed ewe lambs of similar weight (27.29 ± 2.02 kg; aged 3 months) were assigned to two groups, the control group was fed the basal diet (Con group), and the arginine group (Arg group) was supplemented with 1% l-arginine based on the Con group for 90 d. The results suggested that dietary arginine significantly increased final body weight, loin eye muscle area, muscle fiber diameter, cross-sectional area (P < 0.050), and decreased shear force value and cooking loss (P < 0.050), as well as altered the composition and contents of volatile flavor compounds in lambs. Importantly, the total protein (TP) content, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP) activities in serum, branched-chain aminotransferase (BCAT), AST, ALT activities and neuronal nitric oxide synthase (nNOS) gene expression and content were elevated (P < 0.050), while content of urea nitrogen (BUN) in serum and 3-methylhistidine (3-MH) were decreased in arginine fed lambs (P < 0.050). In addition, arginine triggered muscle protein synthesis through protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, while minimized protein degradation by regulating gene expression of myogenin (MyoG), myostatin (MSTN), muscle atrophy F-box (MAFbx) and forkhead box O3 family (FoxO3) (P < 0.050). Taken together, this study suggested that arginine can be used to improve protein deposition and meat quality in lamb production.

L-Arginine Supplementation for Nulliparous Sows during the Last Third of Gestation

We evaluated the effects of L-arginine supplementation during the last third of gestation on molecular mechanisms related to skeletal muscle development of piglets and litter traits at birth. Twenty-three nulliparous sows averaging 205.37 ± 11.50 kg of body weight were randomly assigned to the following experimental treatments: control (CON), where pregnant sows were fed diets to meet their nutritional requirements; arginine (ARG), where sows where fed CON + 1.0% L-arginine. Skeletal muscle from piglets born from sows from ARG group had greater mRNA expression of MYOD (p = 0.043) and MYOG (p ≤ 0.01), and tended to present greater mRNA expression (p = 0.06) of IGF-2 gene compared to those born from CON sows. However, there were no differences (p > 0.05) in the histomorphometric variables of fetuses' skeletal muscle. The total weight of born piglets, total weight of born alive piglets, piglet weight at birth, coefficient of variation of birth weight, and the incidence of intrauterine growth restriction (IUGR) piglets did not differ between groups. No stillborn piglets (p < 0.01) were verified in the ARG sows compared to CON group. The blood levels of estradiol (p = 0.035) and urea (p = 0.03) were higher in ARG sows compared to those from the CON group. In summary, our data show that arginine supplementation of nulliparous sows at late gestation enhance mRNA expression of key myogenic regulatory factors, which likely contribute to improve animal growth rates in later stages of development.

Placental Impact of Dietary Supplements: More Than Micronutrients

PURPOSE

Maternal nutrition is a key modifier of fetal growth and development. However, many maternal diets in the United States do not meet nutritional recommendations. Dietary supplementation is therefore necessary to meet nutritional goals. The effects of many supplements on placental development and function are poorly understood. In this review, we address the therapeutic potential of maternal dietary supplementation on placental development and function in both healthy and complicated pregnancies.

METHODS

This is a narrative review of original research articles published between February 1970 and July 2020 on dietary supplements consumed during pregnancy and placental outcomes (including nutrient uptake, metabolism and delivery, as well as growth and efficiency). Impacts of placental changes on fetal outcomes were also reviewed. Both human and animal studies were included.

FINDINGS

We found evidence of a potential therapeutic benefit of several supplements on maternal and fetal outcomes via their placental impacts. Our review supports a role for probiotics as a placental therapeutic, with effects that include improved inflammation and lipid metabolism, which may prevent preterm birth and poor placental efficiency. Supplementation with omega-3 fatty acids (as found in fish oil) during pregnancy tempers the negative effects of maternal obesity but may have little placental impact in healthy lean women. The beneficial effects of choline supplementation on maternal health and fetal growth are largely attributable to its placental impacts. l-arginine supplementation has a potent provascularization effect on the placenta, which may underlie its fetal growth-promoting properties.

IMPLICATIONS

The placenta is exquisitely sensitive to dietary supplements. Pregnant women should consult their health care practitioner before continuing or initiating use of a dietary supplement. Because little is known about impacts of many supplements on placental and long-term offspring health, more research is required before robust clinical recommendations can be made.

Prenatal Amino Acid Supplementation to Improve Fetal Growth: A Systematic Review and Meta-Analysis

Aberrant fetal growth remains a leading cause of perinatal morbidity and mortality and is associated with a risk of developing non-communicable diseases later in life. We performed a systematic review and meta-analysis combining human and animal studies to assess whether prenatal amino acid (AA) supplementation could be a promising approach to promote healthy fetal growth. PubMed, Embase, and Cochrane libraries were searched to identify studies orally supplementing the following AA groups during gestation: (1) arginine family, (2) branched chain (BCAA), and (3) methyl donors. The primary outcome was fetal/birth weight. Twenty-two human and 89 animal studies were included in the systematic review. The arginine family and, especially, arginine itself were studied the most. Our meta-analysis showed beneficial effects of arginine and (N-Carbamyl) glutamate (NCG) but not aspartic acid and citrulline on fetal/birth weight. However, no effects were reported when an isonitrogenous control diet was included. BCAA and methyl donor supplementation did not affect fetal/birth weight. Arginine family supplementation, in particular arginine and NCG, improves fetal growth in complicated pregnancies. BCAA and methyl donor supplementation do not seem to be as promising in targeting fetal growth. Well-controlled research in complicated pregnancies is needed before ruling out AA supplements or preferring arginine above other AAs.

Effects of L-Arginine Supplementation during Late Gestation on Reproductive Performance, Piglet Uniformity, Blood Profiles, and Milk Composition in High Prolific Sows

This study was conducted to evaluate the effects of L-arginine supplementation levels during late gestation on reproductive performance and piglet uniformity in high prolific sows. A total of 60 F1 multiparous sows (Yorkshire × Landrace), with an average body weight of 238.2 kg, were allotted to one of three treatment groups in a completely randomized design. The dietary treatments were divided by the supplementation level of arginine during the late-gestation period, from day 70 to farrowing, as follows-(1) CON: corn-soybean meal-based basal diet (Arg 0.72%), (2) Arg10: basal diet + L-Arg 0.28% (Arg 1.0%), and (3) Arg15: basal diet + L-Arg 0.79% (Arg 1.5%). The same lactation diet was provided ad libitum to sows during the lactation period. There were no significant differences in body weight and backfat thickness in sows during late-gestation and lactation. Dietary arginine levels had no significant influences on the number of total born, stillbirth, and born alive. However, increasing inclusion level of L-arginine supplementation tended to increase (p < 0.10) alive litter weight linearly, and also linearly increased (p < 0.05) the piglet weight gain and litter weight gain during the lactation period. In piglet uniformity, the standard deviation of piglet birth weight (p < 0.05) and the coefficient of variation for piglet birth weight (p < 0.10) increased linearly, as dietary arginine levels increased in the late gestation period. Increasing L-arginine supplementation to late gestating sows linearly increased (p < 0.05) the blood concentrations of arginine and ornithine at day 90 and day 110 of gestation. On the other hand, dietary arginine levels in late gestation did not affect the blood parameters related to the nitrogen utilization. Increasing dietary arginine levels for the late gestating sows did not affect the milk composition for colostrum and milk at day 21 of lactation. In conclusion, the inclusion level of arginine in the diet for late gestating sows, by up to 1.5%, could improve the alive litter weight at birth and litter weight gain during lactation, whereas the piglet uniformity at birth was decreased due to the increase of survival for fetuses with light birth weight.

Effects of dietary resveratrol supplementation in sows on antioxidative status, myofiber characteristic and meat quality of offspring

This study investigated the influence of dietary resveratrol (300 mg/kg) supplementation in sows on the antioxidative status, myofiber characteristic and meat quality of their progeny. Results showed that maternal dietary resveratrol supplementation increased (P < 0.05) the backfat thickness and tended (P = 0.055) to increase the intramuscular fat of finishing pigs. The drip loss and lactic acid level were reduced, and the pH_{24 h} of longissimus thoracis was increased by maternal dietary resveratrol supplementation (P < 0.05). Maternal dietary resveratrol supplementation increased the mRNA and protein expression of MyHC I and decreased the mRNA and protein expression of MyHC IIb in the longissimus thoracis (P < 0.05). The malonaldehyde (MDA) level in longissimus thoracis was reduced and the superoxide dismutase (SOD) activity and SOD2 mRNA expression were increased by maternal dietary resveratrol supplementation (P < 0.05). In conclusion, dietary resveratrol supplementation in sows improves the meat quality of offspring by altering the myofiber characteristic and antioxidative status.

Effects of dietary γ-aminobutyric acid supplementation on antioxidant status, blood hormones and meat quality in growing-finishing pigs undergoing transport stress

γ-Aminobutyric acid (GABA) is a natural nonprotein amino acid distributed in animals, plants and microbes. GABA is an inhibiting neurotransmitter which takes great effect in mammalian central nervous system. We carried out the research to study the influence of GABA on blood hormone concentrations, antioxidant status and meat quality in fattening pigs after transportation. The 72 pigs with a starting weight of approximately 32.67 ± 0.62 kg were randomly allocated to 2 groups based on dietary treatments, containing 6 replicates with 6 pigs in each. The pigs were fed dietary supplementation of GABA (0 or 30 mg/kg of diets) for 74 days. Twelve pigs were randomly selected from each group and assigned to the either 1 hr of transport (T group) or no transport (N group), resulting in two-factor factorial design. Compared to the control, GABA supplementation increased average daily gain (ADG) (p < .01) and decreased feed-gain ratio (F/G) (p < .05). The pH_45 min was lower and drip loss was greater in the longissimus muscles (LM) of post-slaughter of transported pigs (p < .05). The pH_45 min of 0/T group (group with 0 mg/kg GABA and transport) was significantly lower than the pH_45 min of the 30/T group (diet × transport; p < .05). GABA supplementation significantly increased serum glutathione peroxidase (GSH-Px) concentration (p < .05) before transportation. Following transport, pigs fed GABA had decreased concentrations of serum malonaldehyde (MDA), adrenal cortical hormone and cortisol (p < .05). The results indicate that feeding GABA significantly increased the growth performance of growing-finishing pigs. The transportation model negatively impacted meat quality, antioxidant indexes and hormone parameters, but dietary supplementation of GABA could suppress the rise of drip loss of LM, ACTH and COR and suppress the drop of pH_45 min of LM after transportation stress in growing-finishing pigs. Feeding GABA alleviated transportation stress in pigs.

Effects of Dietary L-arginine Supplementation from Conception to Post- Weaning in Piglets

Weaned piglets experience sudden changes in their dietary patterns such as withdrawal from the easily digestible watery milk to a coarse cereal diet with both systemic and intestinal disruptions coupling with the expression of pro-inflammatory proteins which affects the immune system and the concentrations of haptoglobin including both positive and negative acute-phase proteins in the plasma. L-arginine is an important protein amino acid for piglets, but its inadequate synthesis is a nutritional problem for both sows and piglets. Recent studies indicated that dietary supplementation of L-arginine increased feed intake, uterine growth, placental growth and nutrient transport, maternal growth and health, embryonic survival, piglets birth weight, piglet's growth, and productivity, and decreased stillbirths. L-arginine is essential in several important pathways involved in the growth and development of piglets such as nitric oxide synthesis, energy metabolism, polyamine synthesis, cellular protein production and muscle accretion, and the synthesis of other functional amino acids. However, the underlying molecular mechanism in these key pathways remains largely unresolved. This review was conducted on the general hypothesis that L-arginine increased the growth and survival of post-weaning piglets. We discussed the effects of dietary L-arginine supplementation during gestation, parturition, lactation, weaning, and post-weaning in pigs as each of these stages influences the health and survival of sows and their progenies. Therefore, the aim of this review was to discuss through a logical approach the effects of L-arginine supplementation on piglet's growth and survival from conception to postweaning.

The impact of dietary supplementation of arginine during gestation in a commercial swine herd: I. Gilt reproductive performance

Supplemental arginine (Arg) during gestation purportedly benefits fetal development. However, the benefits of a gestational Arg dietary strategy in commercial production are unclear. Therefore, the objectives of this study examined Arg supplementation during different gestational stages and the effects on gilt reproductive performance. Pubertal gilts (n = 548) were allocated into 4 treatment groups: Control (n = 143; 0% supplemental Arg) or 1 of 3 supplemental Arg (1% as fed) treatments: from 15 to 45 d of gestation (n = 138; Early-Arg); from 15 d of gestation until farrowing (n = 139; Full-Arg); or from 85 d of gestation until farrowing (n = 128; Late-Arg). At farrowing, the number of total born (TB), born alive (BA), stillborn piglets (SB), mummified fetuses (MM), and individual piglet birth weights (BiWt) were recorded. The wean-to-estrus interval (WEI) and subsequent sow reproductive performance (to third parity) were also monitored. No significant effect of supplemental Arg during any part of P0 gestation was observed for TB, BA, SB, or MM (P ≥ 0.29). Offspring BiWt and variation among individual piglet birth weights did not differ (P = 0.42 and 0.89, respectively) among treatment groups. Following weaning, the WEI was similar among treatments (average of 8.0 ± 0.8 d; P = 0.88). Litter performance over 3 parities revealed a decrease (P = 0.02) in BA for Early-Arg fed gilts compared with all other treatments, whereas TB and WEI were similar among treatments over 3 parities (P > 0.05). There was an increased proportion of sows with average size litters (12 to 16 TB) from the Full-Arg treatment sows (76.8% ± 3.7%) when compared with Control (58.7% ± 4.2%; P = 0.01); however, the proportion of sows with high (>16 TB) and low (<12 TB) litters was not different among treatments (P = 0.20). These results suggest that gestational Arg supplementation had a minimal impact on reproductive performance in first parity sows. These data underscore the complexity of AA supplementation and the need for continued research into understanding how and when utilizing a gestational dietary Arg strategy can optimize fetal development and sow performance.

The impact of dietary supplementation of arginine during gestation in a commercial swine herd: II. Offspring performance

Arginine (Arg) is an important amino acid of pig fetal development; however, whether Arg improves postnatal performance is ill-defined. Therefore, the influence of Arg supplementation at different gestational stages on offspring performance was evaluated in a commercial swine herd. Sows (n = 548) were allocated into 4, diet by stage of gestation treatments: Control (n = 143; 0% suppl. Arg), or dietary treatments supplemented with 1% L-Arg (free-base; Ajinomoto Animal Nutrition North America, Inc., Chicago, IL): from 15 to 45 d of gestation (n = 138; Early-Arg); 15 d of gestation to farrowing (n = 139; Full-Arg); and from day 85 of gestation to farrowing (n = 128; Late-Arg). All offspring were individually identified and weighed at birth; at weaning, a subset was selected for evaluation of carcass performance at market. All data were analyzed using birth weight (BiWt) and age as covariates. Wean weights (WW) and prewean (PW) ADG tended to increase (P = 0.06) in progeny from sows supplemented with Arg, as compared to progeny from Control sows. Preplanned contrast comparisons revealed an increased (P = 0.03) BiWt for pigs from sows receiving 1% L-Arg prior to day 45 of gestation (Early-Arg and Full-Arg; 1.38 kg/pig), as compared to pigs from sows not supplemented prior to day 45 of gestation (Control and Late-Arg; 1.34 kg/pig). No difference in BiWt was observed (1.36 kg/pig; P = 0.68) for Arg supplementation after day 85 of gestation (Full-Arg and Late-Arg), as compared to those not receiving Arg supplementation after day 85 (Control and Early-Arg); although WW and PW ADG were greater (P = 0.02), respectively. A 3.6% decrease (P = 0.05) in peak lean accretion ADG occurred when dams received 1% L-Arg prior to day 45 of gestation (Early-Arg and Full-Arg), however, no other significant differences were detected in finishing growth parameters or carcass characteristics (P ≥ 0.1). Pig mortality rates tended (P = 0.07) to decrease in progeny of dams supplemented Arg after day 85 (3.6%) compared to dams not provided additional Arg during late gestation (4.9%). Collectively, these data suggest that Arg provided during late gestation may improve WW and PW ADG, however, finishing performance was not affected. While Arg supplementation provided some moderate production benefits, further investigation is warranted to comprehensively understand the gestational timing and biological role of Arg supplementation during fetal and postnatal development in commercial production systems.

Dietary ractopamine supplementation of pregnant sows: what are the impacts on the neonate?

The use of additives such as ractopamine (Rac) in pregnant sows during early-mid pregnancy is an alternative to increase foetal and progeny growth and development. However, Rac supplementation in finishing pigs can lead to behavioural and physiological changes similar to the typical stress responses. The objective of this study was to evaluate the effects of dietary supplementation with Rac in pregnant sows from day 25 to 50 of gestation (pre-hyperplastic stage) on piglet's vitality, blood parameters, number, diameter and perimeter of muscle fibres in semitendinosus muscle and developmental characteristics of piglets at birth to weaning. Forty-one hybrid sows were divided into three dietary treatments: (1) control diet without Rac (control), (2) addition of 10 mg/kg of Rac (Rac10) and (3) addition of 20 mg/kg of Rac (Rac20). Higher numbers of low-vitality piglets (P<0.05) were observed in Rac-fed sows, regardless of dose, compared with the control group. Very low-density lipoprotein levels were lower in the Rac10 group when compared with the Rac20 group at day 21. Haematocrit was greater, and the mean corpuscular haemoglobin concentration was lower in piglets from Rac-fed sows. No significant statistical differences were detected regarding piglets body weight, average daily gain, blood gasometry, complete blood count and muscle fibre measurements in semitendinosus muscle. The use of Rac in pregnant sows reduced the vitality parameters of piglets but did not improve the performance from birth until weaning and did not negatively influence the haematological parameter and lipid metabolism.

Increasing selenium supply for heat-stressed or actively cooled sows improves piglet preweaning survival, colostrum and milk composition, as well as maternal selenium, antioxidant status and immunoglobulin transfer

This study aimed to evaluate the effects of increasing selenium (Se) supply for heat-stressed or actively cooled sows on sow productivity, colostrum and milk composition, as well as the selenium and antioxidant status and immunoglobulin levels of sows and nursing piglets. The study was a 2 × 2 factorial design, where the first factor was farrowing environment [heat stress vs. actively cooling, temperature: 29.61 ± 0.19 ℃ (27.70-31.60 ℃) vs. 27.90 ± 0.15 ℃ (26.90-30.20 ℃); temperature-humidity index: 72.91 ± 0.26 (70.30-75.70) vs. 70.81 ± 0.22 (69.30-73.80)], and the second factor was dietary Se level during late gestation and lactation [(0.3 vs. 1.2 mg/kg Se as Se-yeast, the basal diet was corn-soybean meal diet formulated according to NRC (2012) except for Se level]. Forty multiparous sows (Landrace × Yorkshire) were randomly allotted to 1 of 4 treatments (10 sows and following 90 piglets per treatment, respectively). The results show that: (1) There were no interactions of farrowing environment with Se treatments with the exceptions of nutrient content of 7-d milk; (2) As for zootechnical measures, piglets of sows receiving increasing Se tended to have greater preweaning survival compared with those of sows receiving control diet without interactions of environment and Se treatments; (3) As to colostrum and milk composition, greater concentrations of protein, lactose, solids-not-fat in colostrum, and greater fat concentration in 7-d and 14-d milk were found for sows fed increasing Se; (4) Regarding Se and antioxidant status, increasing Se supply for sows increased Se content in colostrum and 21-d milk, as well as in plasma of 1-day-old and 21-day-old piglets. Meanwhile, increasing Se supply for sows improved antioxidant status in colostrum (MDA content) and 21-d milk (T-AOC and MDA content), as well as in plasma of 1-day-old and 21-day-old piglets (GSH-Px activity and MDA content); (5) With regard to immunoglobulins, sows fed increasing Se had higher IgM levels in colostrum, and higher IgA in 21-d milk. Also, piglets from sows fed increasing Se had higher plasma IgA at 1 d of age, and higher IgA and IgG levels at 21 d of age. Collectively, increasing selenium supply for heat-stressed or actively cooled sows improved piglet preweaning survival, colostrum and milk composition, as well as maternal selenium, antioxidant status and immunoglobulin transfer irrespective of the climatic conditions, which indicates that Se requirements for sows should be urgently reassessed.

BOARD-INVITED REVIEW: Arginine nutrition and metabolism in growing, gestating, and lactating swine

Arginine (Arg) has traditionally not been considered as a deficient nutrient in diets for gestating or lactating swine due to the assumption that these animals can synthesize sufficient amounts of Arg to meet their physiological needs. The lack of full knowledge about Arg nutrition has contributed to suboptimal efficiency of pork production. Over the past 25 yr, there has been growing interest in Arg metabolism in the pig, which is an agriculturally important species and a useful model for studying human biology. Arginine is a highly abundant amino acid in tissues of pigs, a major amino acid in allantoic fluid, and a key regulator of gene expression, cell signaling, and antioxidative reactions. Emerging evidence suggests that dietary supplementation with 0.5% to 1% Arg maintains gut health and prevents intestinal dysfunction in weanling piglets, while enhancing their growth performance and survival. Also, the inclusion of 1% Arg in diets is required to maximize skeletal muscle accretion and feed efficiency in growing pigs, whereas dietary supplementation with 1% Arg reduces muscle loss in endotoxin-challenged pigs. Furthermore, supplementing 0.83% Arg to corn- and soybean meal-based diets promotes embryonic/fetal survival in swine and milk production by lactating sows. Thus, an adequate amount of dietary Arg as a quantitatively major nutrient is necessary to support maximum growth, lactation, and reproduction performance of swine. These results also have important implications for improving the nutrition and health of humans and other animals.

Dietary supplementation of l-arginine and chromium picolinate in sows during gestation affects the muscle fibre characteristics but not the performance of their progeny

BACKGROUND

The present study investigated the effects of dietary supplementation of l-arginine and chromium picolinate (CrP) in sows during gestation on muscle fibre characteristics, performance and carcass characteristics of their progeny. Sixty healthy sows were randomly divided into four groups as a 2 × 2 factorial experiment design: one group received the control diet, another received the control diet + 10 g kg^-1 l-arginine, the third group received the control diet + 400 ppb CrP, and the fourth group received the control diet + 10 g kg^-1 l-arginine and 400 ppb CrP.

RESULTS

The results showed that sows fed the diet supplemented with CrP produced progeny with higher muscle fibre numbers at birth, weaning and slaughter compared to sows fed the control diet. For mean fibre areas, the same result was found at weaning. For progeny of sows fed diets supplemented with l-arginine, only higher muscle fibre numbers at slaughter was observed. Almost no differences were observed regarding average daily gains, average daily feed intake, gain-to-feed ratios, carcass and meat traits.

CONCLUSION

The results of the present study indicate that dietary supplementation of l-arginine and particularly CrP in sows during gestation alters muscle fibre numbers in their offspring, although not their performance or carcass characteristics. © 2017 Society of Chemical Industry.

A multivariate approach to determine the factors affecting response level of growth, carcass, and meat quality traits in finishing pigs fed ractopamine

The effect of ractopamine (RAC) supplementation on growth, carcass, and meat quality traits of finishing pigs was studied using a meta-analytical approach. The database was composed of 57 studies published from 2004 to 2016. The dependent variables extracted for the meta-analysis included final BW, ADG, ADFI, feed:gain ratio, HCW, dressing percentage, carcass length, lean yield, back fat thickness, loin muscle area, loin depth, postmortem pH, meat brightness, redness, and yellowness. The studies were grouped by similarity in 3 clusters (C1, C2, and C3) by hierarchical clustering on principle components. The main differences observed between clusters were those of animal initial weight, which increased from C1 through C3. Linear mixed models were used to analyze the data, where studies were assumed as random effect, whereas the total amount of RAC in the diet, cluster, and sex category were considered fixed effects. The interactions between cluster and sex category (barrows, gilts, and mixed sex) and RAC level were also evaluated. Dietary RAC was effective in improving final weight ( < 0.0001), ADG ( < 0.0001), and feed:gain ratio ( < 0.0001) and had a positive effect on HCW ( < 0.0001), lean yield ( = 0.0081), loin muscle area ( = 0.0190), and loin depth ( < 0.0001). In addition, a relatively limited effect on pork quality was observed in the current study. The RAC supplementation was more effective, mainly when pigs started supplementation with higher initial weight, although different responses were observed according to sex category ( < 0.05). There is ample indication that growth and carcass traits could be improved by dietary RAC supplementation. Ractopamine supplementation did not influence the pork quality.

Arginine for gestating sows and foetal development: A systematic review

The use of functional amino acids during pregnancy has been linked to improved reproduction in mammals. In this context, arginine is a precursor in the synthesis of numerous molecules, such as nitric oxide and polyamines, which play an important role during reproduction. However, contradictory studies are found in the literature, particularly regarding the amount of supplementation and the period of pregnancy in which it is used. The objective of this study was to evaluate the effects of dietary arginine supplementation for pregnant sows on foetal development via a systematic review. The search for papers was performed during the month of December 2015, in the databases ISI Web of Science, Science Direct, Scopus, and SciELO. From a total of 5675 returned studies, only 13 papers were selected after applying selection criteria. Most (47%) of the studies that evaluated the effects of dietary arginine supplementation on foetal development in pigs used 1% arginine. Supplementation was initiated in the first third of pregnancy in 47% of tests, including in both primiparous and multiparous sows. These studies showed positive results for embryo survival and foetal development, evidenced by the increase in placental weight and the number and weight of piglets born alive. Of all evaluated studies, 53% showed benefits on foetal development. It is concluded that supplementing dietary arginine in gestating sows can benefit embryo survival and foetal development. However, to establish a supplementation plan with this amino acid, aspects related to the period of pregnancy, supplementation levels, and source of arginine must be well defined.