Changes in plasma amino acid profiles, growth performance and intestinal antioxidant capacity of piglets following increased consumption of methionine as its hydroxy analogue

Serum metabolomics analysis reveals a novel association between maternal metabolism and fetal survival in sows fed diets containing differing methionine levels and sources

Methionine (Met) metabolism is vital for one carbon metabolism, redox status and fetal development. Hence, this study investigated the effects of different levels and sources of Met on maternal metabolism, anti-oxidative capacity and fetal survival in pregnant sows. Forty primiparous sows were assigned to the following four groups: control group (basal diet, CON), 1.5S-OHMet group (supplemented methionine hydroxy analogue [OHMet] at 1.5 g/kg diet), 3.0S-OHMet group (supplemented OHMet at 3.0 g/kg diet), and 3.0S-Met group (supplemented L-Met at 3.0 g/kg diet) (n = 10). The trial lasted from day 60 of gestation to the farrowing day. Maternal 1.5S-OHMet consumption had the lowest stillborn ratio and the highest serum glucose levels during farrowing. Further analysis revealed that dietary 1.5S-OHMet consumption elevated the serum contents of glucose-6-phosphate, citric acid, butyric acid, malic acid, 3-methyladenine, 1-methyladenosine, ferulic acid and salicylic acid, but reduced the serum contents of succinic acid, oxoglutaric acid, 9(S)-hydroperoxylinoleic acid, 13(S)-hydroperoxy-octadecatrienoic acid, uric acid and urea nitrogen when compared to contents observed in the 3.0S-OHMet and 3.0S-Met groups (P < 0.05). Serum metabolomics analysis was conducted to determine the enriched differential metabolites and an enrichment analysis was performed using Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The results showed that the enriched metabolites were mainly associated with central carbon metabolism, amino acid metabolism, lipid metabolism, and nucleotide metabolism. Moreover, maternal 3.0S-OHMet or 3.0S-Met consumption upregulated the trans-methylation pathway by elevating the S-adenosyl-methionine (SAM) level and the ratio of SAM to S-adenosyl-homocysteine (P < 0.05) at day 114 of gestation, while increasing homocysteine concentration (P < 0.001). However, compared to the 3.0S-Met group, maternal 3.0S-OHMet consumption elevated fetal survival and glutathione peroxidase (P < 0.05). Thus, this study provided new insights into the mechanisms through which sows fed with a 1.5S-OHMet diet during mid-to late-gestation period had high fetal survival, such as improvements in maternal amino acid, nucleotide and glycolipid metabolism.

Methionine Source and Level Modulate Gut pH, Amino Acid Transporters and Metabolism Related Genes in Broiler Chickens

This study determined the effects of two methionine (Met) sources at three total sulfur amino acids (TSAA) to lysine ratios (TSAA/Lys) on gut pH, digestive enzyme activity, amino acid transporter expression, and Met metabolism of broilers. The birds were randomly assigned to a 2 × 3 factorial arrangement with Met sources (dl-Met and dl-2-hydroxy-4-(methylthio)-butanoic acid (OH-Met)) and TSAA/Lys (0.58, 0.73, and 0.88) from 1 to 21 days. The results demonstrated that dl-Met and OH-Met supported the same growth performance, but high TSAA/Lys ratio reduced the feed intake and body weight (P < 0.05). OH-Met reduced the crop chyme pH and enhanced the jejunal lipase activity (P < 0.05). ATB0,+ expression decreased with increased dl-Met levels in the duodenum; the low TSAA/Lys ratio induced a stronger mRNA expression of basolateral Met transporters. OH-Met resulted in an increase of cystathionine β-synthase expression in the liver and a decrease in serum homocysteine levels at middle TSAA/Lys ratio compared with dl-Met treatment (P < 0.05). In conclusion, two Met sources support the same growth, but OH-Met acidified the crop chyme. The investigated transporter transcripts differed significantly along the small intestine. At the middle TSAA/Lys ratio, OH-Met showed a higher metabolic tendency of the trans-sulfuration pathway compared with dl-Met.

A novel antibacterial strategy for targeting the bacterial methionine biosynthesis pathway

Bacterial pathogens reprogramme their metabolic networks to support growth and establish infection at specific sites. Bacterial central metabolism has been considered attractive for developing antimicrobial drugs; however, most metabolic enzymes are conserved between humans and bacteria. This study found that blockade of methionine biosynthesis in Citrobacter rodentium and Salmonella enteritidis inhibited bacterial growth and activity of the type III secretion system, resulting in severe defects in colonization and pathogenicity. In addition, α-methyl-methionine was found to inhibit the activity of methionine biosynthetic enzyme MetA, and consequently reduce the virulence and pathogenicity of enteric pathogens. These findings highlight the crucial role of methionine in bacterial virulence, and describe a potential new drug target.

Dietary methionine sources and levels modulate the intestinal health status of broiler chickens

Given the key role of methionine in biological processes, adequate methionine should be provided to meet the nutritional requirements. DL-2-hydroxy-4-(methylthio)-butanoic acid (DL-HMTBA) has been considered as an important source of methionine. However, the effects of different sources and levels of methionine on the intestinal health status have not been clarified yet. An experiment was carried out to investigate the effects of different dietary sources and levels of methionine on the intestinal epithelial barrier, inflammatory cytokines expression, ileal morphology, microbiota composition, and cecal short chain fatty acids (SCFA) profiles. For this purpose, 720 male Arbor Acre broiler chicks at 1 d old were randomly assigned to a 2 × 3 factorial arrangement with 2 methionine sources (DL-methionine and DL-HMTBA) and 3 total sulfur amino acids (TSAA) levels (80%, 100%, and 120% of Arbor Acre recommendation). The results showed that DL-HMTBA supplementation promoted intestinal physical barrier at both gene expression level of claudin-1 and serum diamine oxidase level (P < 0.05), and the inflammatory cytokine IL-6 mRNA expression was down-regulated by dietary DL-HMTBA supplementation compared with the DL-methionine group (P < 0.05). Meanwhile, an upregulated gene expression of claudin-1 and zonula occluden-1 (ZO-1) were observed in the low-TSAA treatment on d 14 (P < 0.05), whereas this treatment increased the expression of IL-1β and IL-6 (P < 0.05). Villus height to crypt depth ratio was high (P < 0.05) in the middle-level TSAA group. Furthermore, DL-HMTBA supplementation optimized the microbiota of the ileum especially the relative abundance of Lactobacillus, where the digestion and absorption were completed, and elevated the concentrations of SCFA (acetate, propionate, and butyrate) in the cecal content on d 21 (P < 0.01). In conclusion, dietary DL-HMTBA supplementation improved the intestinal barrier function, immune homeostasis and optimized the microbiota to promote intestinal health status in broiler chickens.

Effects of dietary methionine supplementation from different sources on growth performance and meat quality of barrows and gilts

Methionine is indispensable for growth and meat formation in pigs. However, it is still unclear that increasing dietary sulphur-containing amino acid (SAA) levels using different methionine sources affects the growth performance and meat quality of barrows and gilts. To investigate this, 144 pigs (half barrows and half gilts) were fed the control (100% SAA, CON), DL-Methionine (125% SAA, DL-Met)-supplemented, or OH-Methionine (125% SAA, OH-Met)-supplemented diets during the 11-110 kg period. The results showed that plasma methionine levels varied among treatments during the experimental phase, with increased plasma methionine levels observed following increased SAA consumption during the 25-45 kg period. In contrast, pigs fed the DL-Met diet had lower plasma methionine levels than those fed the CON diet (95-110 kg). Additionally, gilts fed the DL-Met or OH-Met diets showed decreased drip loss in longissimus lumborum muscle (LM) compared to CON-fed gilts. OH-Met-fed gilts had higher pH45min values than those fed the CON or DL-Met diets, whereas OH-Met-fed barrows had higher L45min values than those fed the CON or DL-Met diets. Moreover, increased consumption of SAA, regardless of the methionine source, tended to decrease the shear force of the LM in pigs. In conclusion, this study indicates that increasing dietary levels of SAA (+25%) appeared to improve the meat quality of gilts by decreasing drip loss and increasing meat tenderness.

The Linear-Logistic Model: A Novel Paradigm for Estimating Dietary Amino Acid Requirements

This study aimed to determine whether current methods for estimating AA requirements for animal health and welfare are sufficient. An exploratory data analysis (EDA) was conducted, which involved a review of assumptions underlying AA requirements research, a data mining approach to identify animal responses to dietary AA levels exceeding those for maximum protein retention, and a literature review to assess the physiological relevance of the linear-logistic model developed through the data mining approach. The results showed that AA dietary levels above those for maximum growth resulted in improvements in key physiological responses, and the linear-logistic model depicted the AA level at which growth and protein retention rates were maximized, along with key metabolic functions related to milk yield, litter size, immune response, intestinal permeability, and plasma AA concentrations. The results suggest that current methods based solely on growth and protein retention measurements are insufficient for optimizing key physiological responses associated with health, survival, and reproduction. The linear-logistic model could be used to estimate AA doses that optimize these responses and, potentially, survival rates.

Use of Organic Acid Mixtures Containing 2-Hydroxy-4-(Methylthio) Butanoic Acid (HMTBa) to Mitigate Salmonella enterica, Shiga Toxin-Producing Escherichia coli (STEC) and Aspergillus flavus in Pet Food Kibbles

Post-processing operations of extruded pet food kibbles involve coating the product with fats and flavorings. These processes increase the risk for cross-contamination with food-borne pathogens such as Salmonella and Shiga toxin-producing Escherichia coli (STEC), and mycotoxin-producing molds such as Aspergillus spp. after the thermal kill step. In this study, the antimicrobial effects of two types of organic acid mixtures containing 2-hydroxy-4-(methylthio) butanoic acid (HMTBa), Activate DA™ and Activate US WD-MAX™, against Salmonella enterica, STEC and Aspergillus flavus when used as a coating on pet food kibbles were evaluated. Using canola oil and dry dog digest as fat and flavor coatings, the efficacy of Activate DA (HMTBa + fumaric acid + benzoic acid) at 0%, 1% and 2%, and Activate US WD-MAX (HMTBa + lactic acid + phosphoric acid) at 0%, 0.5% and 1% was tested on kibbles inoculated with a cocktail of S. enterica serovars (Enteritidis, Heidelberg and Typhimurium) or Shiga toxin-producing E. coli (STEC) serovars (O121, and O26) at 37 °C for 0, 12, 24, 48, 72 h, 30 and 60 days. Similarly, their efficacy was tested against A. flavus at 25 °C for 0, 3, 7, 14, 21, 28 and 35 days. Activate DA at 2% and Activate US WD-MAX at 1% reduced Salmonella counts by ~3 logs after 12 h and 4-4.6 logs after 24 h. Similarly, STEC counts were reduced by ~2 logs and 3 logs after 12 h and 24 h, respectively. Levels of A. flavus did not vary up to 7 days, and afterwards started to decline by >2 logs in 14 days, and up to 3.8-log reduction in 28 days for Activate DA and Activate US WD-MAX at 2% and 1%, respectively. The results suggest that the use of these organic acid mixtures containing HMTBa during kibble coating may mitigate post-processing enteric pathogen and mold contamination in pet food kibbles, with Activate US WD-MAX being effective at a lower concentration (0.5-1%) compared to Activate DA.

Mitigation of Salmonella on Food Contact Surfaces by Using Organic Acid Mixtures Containing 2-Hydroxy-4-(methylthio) Butanoic Acid (HMTBa)

Contaminated surfaces can transmit pathogens to food in industrial and domestic food-handling environments. Exposure to pathogens on food contact surfaces may take place via the cross-contamination of pathogens during postprocessing activities. Formaldehyde-based commercial sanitizers in recent years are less commonly being used within food manufacturing facilities due to consumer perception and labeling concerns. There is interest in investigating clean-label, food-safe components for use on food contact surfaces to mitigate contamination from pathogenic bacteria, including Salmonella. In this study, the antimicrobial effects of two types of organic acid mixtures containing 2-hydroxy-4-(methylthio) butanoic acid (HMTBa), Activate DA™ and Activate US WD-MAX™, against Salmonella when applied onto various food contact surfaces were evaluated. The efficacy of Activate DA (HMTBa + fumaric acid + benzoic acid) at 1% and 2% and Activate US WD-MAX (HMTBa + lactic acid + phosphoric acid) at 0.5% and 1% against Salmonella enterica (serovars Enteritidis, Heidelberg, and Typhimurium) were evaluated on six different material surfaces: plastic (bucket elevator and tote bag), rubber (bucket elevator belt and automobile tire), stainless steel, and concrete. There was a significant difference in the Salmonella log reduction on the material surfaces due to the organic acid treatments when compared to the untreated surfaces. The type of material surface also had an effect on the log reductions obtained. Stainless steel and plastic (tote) had the highest Salmonella log reductions (3-3.5 logs), while plastic (bucket elevator) and rubber (tire) had the lowest log reductions (1-1.7 logs) after treatment with Activate US WD-MAX. For Activate DA, the lowest log reductions (~1.6 logs) were observed for plastic (bucket elevator) and rubber (tire), and the highest reductions were observed for plastic (tote), stainless steel, and concrete (2.8-3.2 logs). Overall, the results suggested that Activate DA at 2% and Activate US WD-MAX at 1% are potentially effective at reducing Salmonella counts on food contact surfaces by 1.6-3.5 logs.

Methionine played a positive role in improving the intestinal digestion capacity, anti-inflammatory reaction and oxidation resistance of grass carp, Ctenopharyngodon idella, fry

A study was carried out to appraisal the function of methionine on intestinal digestion and the health of grass carp (Ctenopharyngodon idella) fry (initial weight 0.36 ± 0.01 g). The fry were fed graded dietary methionine levels (0.33%-1.20% dry matter) in 18 recirculatory tanks (180 L). After an 8-week breeding experiment, the results revealed that 0.71%-1.20% dietary methionine levels markedly upregulated the mRNA levels of intestinal digestion including trypsin, amylase, chymotrypsin and AKP, and 0.71%-0.87% dietary methionine level significantly increased intestinal trypsin activities compared with the 0.33% dietary methionine level. For inflammation, 0.71%-1.20% dietary methionine levels downregulated the mRNA levels of NF-κBp65, IL-1β, IL-6, IL-8, IL-15 and IL-17D, whereas upregulated the mRNA levels of anti-inflammatory cytokines, including IL-4/13B, IL-10 and IL-11. In terms of antioxidants, although dietary methionine levels had no significant effect on the expression of most core genes of the Nrf2/ARE signaling pathway, such as Nrf2, Keap 1, GPx4, CAT, Cu/Zn-SOD. Furthermore, dietary methionine levels had no significant effect on the expression of p38MAPK, IL-12p35, TGF-β2 and IL-4/13A. 0.71%-1.20% dietary methionine levels still increased the mRNA levels of GPx1α, GSTR and GSTP1. Furthermore, higher intestinal catalase activity and glutathione contents were also observed in fry fed 0.71%-1.20% diets. In summary, 0.71%-1.20% dietary methionine levels played a positive role in improving the intestinal digestion capacity of digestion, anti-inflammatory reaction and oxidation resistance of grass carp fry. This study provided a theoretical basis for improving the survival rate and growth of grass carp fry.

Maternal probiotics supplementation improves immune and antioxidant function in suckling piglets via modifying gut microbiota

AIM

Probiotics could improve the health, growth and development of host or their fetuses/offspring via regulating gut microbiota. The present study was conducted to determine the effects of maternal probiotics supplementation on gut microbiota and metabolites of sows and their suckling piglets, as well as plasma biochemical parameters, oxidative/anti-oxidative indexes, and inflammatory cytokine levels of suckling piglets.

METHODS AND RESULTS

A total of 32 pregnant Bama mini-pigs were selected and randomly divided into two groups. The sows were fed a basal diet (control group) or a basal diet supplemented with probiotics (probiotics group) from mating to day 21 of lactation. Samples from sows were collected on day 105 of pregnancy and day 21 of lactation and from piglets on day 21 of lactation. The results showed that probiotics supplementation increased the fecal abundances of Ruminococcus, Bacteroides, and Anaeroplasma and decreased Tenericutes on day 105 of pregnancy, while increased the abundances of Actinobacteria and Anaerostipes and decreased Proteobacteria and Desulfovibrio on day 21 of lactation. In addition, probiotics supplementation decreased the fecal levels of tryptamine, putrescine, and cadaverine on day 105 of pregnancy and isovalerate and skatole on day 21 of lactation, while increased butyrate level on day 21 of lactation. Further studies showed that maternal probiotics supplementation decreased the plasma levels of AMM, TC, LDL-C, Ala, Tau, MDA, H₂ O₂ , IL-1β, IL-2, IL-6, and IFN-α of suckling piglets. Moreover, maternal probiotics supplementation increased the abundances of Deferribacteres, Fusobacteria, and Fusobacterium, while decreased Anaerostipes in piglet's colon. The Spearman's correlation analysis revealed a potential link between gut microbiota alterations and their metabolites.

CONCLUSIONS

Dietary probiotics supplementation during pregnancy and lactation periods could improve sow status, alleviate oxidative stress and inflammation response, and improve nutrient metabolism of piglets by altering the gut microbiota.

Dietary methionine source alters the lipidome in the small intestinal epithelium of pigs

Methionine (Met) as an essential amino acid has key importance in a variety of metabolic pathways. This study investigated the influence of three dietary Met supplements (0.21% L-Met, 0.21% DL-Met and 0.31% DL-2-hydroxy-4-(methylthio)butanoic acid (DL-HMTBA)) on the metabolome and inflammatory status in the small intestine of pigs. Epithelia from duodenum, proximal jejunum, middle jejunum and ileum were subjected to metabolomics analysis and qRT-PCR of caspase 1, NLR family pyrin domain containing 3 (NLRP3), interleukins IL1β, IL8, IL18, and transforming growth factor TGFβ. Principal component analysis of the intraepithelial metabolome revealed strong clustering of samples by intestinal segment but not by dietary treatment. However, pathway enrichment analysis revealed that after L-Met supplementation polyunsaturated fatty acids (PUFA) and tocopherol metabolites were lower across small intestinal segments, whereas monohydroxy fatty acids were increased in distal small intestine. Pigs supplemented with DL-HMTBA showed a pronounced shift of secondary bile acids (BA) and sphingosine metabolites from middle jejunum to ileum. In the amino acid super pathway, only histidine metabolism tended to be altered in DL-Met-supplemented pigs. Diet did not affect the expression of inflammation-related genes. These findings suggest that dietary supplementation of young pigs with different Met sources selectively alters lipid metabolism without consequences for inflammatory status.

Feeding intact proteins, peptides, or free amino acids to monogastric farm animals

For terrestrial farm animals, intact protein sources like soybean meal have been the main ingredients providing the required amino acids (AA) to sustain life. However, in recent years, the availability of hydrolysed protein sources and free AA has led to the use of other forms of AA to feed farm animals. The advent of using these new forms is especially important to reduce the negative environmental impacts of animal production because these new forms allow reducing the dietary crude protein content and provide more digestible materials. However, the form in which dietary AA are provided can have an effect on the dynamics of nutrient availability for protein deposition and tissue growth including the efficiency of nutrient utilization. In this literature review, the use of different forms of AA in animal diets is explored, and their differences in digestion and absorption rates are focused on. These differences affect the postprandial plasma appearance of AA, which can have metabolic consequences, like greater insulin response when free AA or hydrolysates instead of intact proteins are fed, which can have a profound effect on metabolism and growth performance. Nevertheless, the use and application of the different AA forms in animal diets are important to achieve a more sustainable and efficient animal production system in the future, as they allow for a more precise diet formulation and reduced negative environmental impact. It is, therefore, important to differentiate the physiological and metabolic effects of different forms of AA to maximize their nutritional value in animal diets.

Dietary supplementation of methionine mitigates oxidative stress in broilers under high stocking density

We aimed to investigate whether dietary supplementation of methionine could mitigate intestinal oxidative injury in broilers under high stocking density (HSD). In the grower phase (d 22–42), 576 broilers with similar body weight were randomly chosen and divided into 8 groups in a 2 × 4 factorial experiment. Two different stocking densities (14 and 20 broilers per m²) were tested with 4 different methionine levels: 0.35%, 0.4%, 0.45%, or 0.5%. Intestinal morphological and oxidative stress markers were assessed at the end of the test period. The results showed that mortality of broilers was significantly higher in the HSD group fed 0.35% methionine diet than the other groups, which was reversed by supplementation with 0.40% to 0.50% methionine. HSD significantly decreased feed intake and daily weight gain. HSD treatment significantly decreased T-AOC, activity of GPX (P < 0.01) and increased the level of PCO (P < 0.01), MDA (P = 0.052) of plasma. The decreased glutathione peroxidase activity in the liver and jejunum caused by HSD was alleviated by additional methionine. Supplementation of methionine increased the ration of GSH/GSSG in the plasma. The jejunum villus height and ratio of villus height to crypt depth under low stocking density conditions with 0.40% methionine diet were the highest, whereas the 0.45% methionine group was the highest under HSD conditions. Thus, additional dietary supplementation of methionine mitigates oxidative stress in broilers under HSD conditions and 0.40% to 0.45% methionine can be applied in cage rearing broiler production for amelioration of oxidative stress caused by HSD.

Qualitative Nitrogen Malnutrition Damages Gut and Alters Microbiome in Adult Mice. A Preliminary Histopathological Study

Amino-acids (AAs) are the exclusive source of nitrogen for cells. AAs result from the breakdown of food proteins and are absorbed by mucosa of the small intestine that act as a barrier to harmful materials. The quality of food proteins may differ, since it reflects content in Essential-AAs (EAAs) and digestibility but, until now, attention was paid mainly to the interaction between indigested proteins as a whole and microbiota. The link between microbiome and quality of proteins has been poorly studied, although these metabolic interactions are becoming more significant in different illnesses. We studied the effects of a special diet containing unbalanced EAAs/Non-EAAs ratio, providing excess of Non-EAAs, on the histopathology of gut epithelium and on the microbiome in adult mice, as model of qualitative malnutrition. Excess in Non-EAAs have unfavorable quick effect on body weight, gut cells, and microbiome, promoting weakening of the intestinal barrier. Re-feeding these animals with standard diet partially reversed the body alterations. The results prove that an unbalanced EAAs/Non-EAAs ratio is primarily responsible for microbiome modifications, not vice-versa. Therefore, treating microbiota independently by treating co-existing qualitative malnutrition does not make sense. This study also provides a reproducible model of sarcopenia-wasting cachexia like the human protein malnutrition.

Changes of the glutathione redox system during the weaning transition in piglets, in relation to small intestinal morphology and barrier function

Background

Weaning is known to result in barrier dysfunction and villus atrophy in the immediate post-weaning phase, and the magnitude of these responses is hypothesized to correlate with changes in the glutathione (GSH) redox system. Therefore, these parameters were simultaneously measured throughout the weaning phase, in piglets differing in birth weight category and weaning age, as these pre-weaning factors are important determinants for the weaning transition. Low birth weight (LBW) and normal birth weight (NBW) littermates were assigned to one of three weaning treatments; i.e. weaning at 3 weeks of age (3w), weaning at 4 weeks of age (4w) and removal from the sow at 3 d of age and fed a milk replacer until weaning at 3 weeks of age (3d3w). For each of these treatments, six LBW and six NBW piglets were euthanized at 0, 2, 5, 12 or 28 d post-weaning piglets, adding up 180 piglets.

Results

Weaning increased the glutathione peroxidase activity on d 5 post-weaning in plasma, and duodenal and jejunal mucosa. Small intestinal glutathione-S-transferase activity gradually increased until d 12 post-weaning, and this was combined with a progressive rise of mucosal GSH up till d 12 post-weaning. Oxidation of the GSH redox status (GSH/GSSG E_h) was only observed in the small intestinal mucosa of 3d3w weaned piglets at d 5 post-weaning. These piglets also demonstrated increased fluorescein isothiocyanate dextran (FD4) and horseradish peroxidase fluxes in the duodenum and distal jejunum during the experiment, and specifically demonstrated increased FD4 fluxes at d 2 to d 5 post-weaning. On the other hand, profound villus atrophy was observed during the weaning transition for all weaning treatments. Finally, LBW and NBW piglets did not demonstrate notable differences in GSH redox status, small intestinal barrier function and histo-morphology throughout the experiment.

Conclusion

Although moderate changes in the GSH redox system were observed upon weaning, the GSH redox status remained at a steady state level in 3w and 4w weaned piglets and was therefore not associated with weaning induced villus atrophy. Conversely, 3d3w weaned piglets demonstrated GSH redox imbalance in the small intestinal mucosa, and this co-occurred with a temporal malfunction of their intestinal barrier function.

Substitution of Dietary Sulfur Amino Acids by dl-2-Hydroxy-4-Methylthiobutyric Acid Reduces Fractional Glutathione Synthesis in Weaned Piglets

BACKGROUND

Cys is limiting for reduced glutathione (GSH) synthesis and can be synthesized from Met. We hypothesized that the dietary Met hydroxyl analogue dl-2-hydroxy-4-methylthiobutyric acid (dl-HMTBA) affects Cys and GSH metabolism and oxidative stress defense differently than Met.

OBJECTIVE

The objective was to elucidate whether dl-HMTBA supplementation of a Met-deficient diet affects Cys flux, GSH fractional synthetic rate (FSR), and the basal oxidative stress level relative to Met supplementation in pigs.

METHODS

Twenty-nine male German Landrace piglets aged 28 d were allocated to 3 dietary groups: a basal diet limiting in Met (69% of Met plus Cys requirement) supplemented with either 0.15% l-Met (LMET; n = 9), 0.15% dl-Met (DLMET; n = 11), or 0.17% dl-HMTBA (DLHMTBA; n = 9) on an equimolar basis. At age 54 d the pigs received a continuous infusion of [1-13C]-Cys to calculate Cys flux and Cys oxidation. After 3 d, GSH FSR was determined by [2,2-2H2]-glycine infusion, and RBC GSH and oxidized GSH concentrations were measured. At age 62 d the animals were killed to determine hepatic mRNA abundances of enzymes involved in GSH metabolism, GSH concentrations, and plasma oxidative stress defense markers.

RESULTS

The Cys oxidation was 21-39% and Cys flux 5-15% higher in the fed relative to the feed-deprived state (P < 0.001). On average, GSH FSR was 49% lower (P < 0.01), and RBC GSH and total GSH concentrations were 12% and 9% lower, respectively, in DLHMTBA and DLMET relative to LMET pigs (P < 0.05). In the feed-deprived state, Gly flux, the GSH:oxidized glutathione (GSSG) ratio, RBC GSSG concentrations, plasma oxidative stress markers, and the hepatic GSH content did not differ between groups.

CONCLUSIONS

Although GSH FSR was higher in LMET compared with DLMET or DLHMTBA feed-deprived pigs, these differences were not reflected by lower oxidative stress markers and antioxidant defense enzymes in LMET pigs.

Increased Consumption of Sulfur Amino Acids by Both Sows and Piglets Enhances the Ability of the Progeny to Adverse Effects Induced by Lipopolysaccharide

This study determined the effects of increased consumption of sulfur amino acids (SAA), as either DL-Met or Hydroxy-Met (OH-Met), by sows and piglets on their performance and the ability of the progeny to resist a lipopolysaccharide (LPS) challenge. Thirty primiparous sows were fed a diet adequate in SAA (CON) or CON + 25% SAA, either as DL-Met or OH-Met from gestation day 85 to postnatal day 21. At 35 d old, 20 male piglets from each treatment were selected and divided into 2 groups (n = 10/treatment) for a 3 × 2 factorial design [diets (CON, DL-Met or OH-Met) and challenge (saline or LPS)]. OH-Met and/or DL-Met supplementation increased (p ≤ 0.05) piglets' body weight gain during day 0-7 and day 7-14. Sow's milk quality was improved in the supplemented treatments compared to the CON. The LPS challenge decreased (p ≤ 0.05) piglets' performance from 35 to 63 d and increased (p ≤ 0.05) the levels of aspartate aminotransferase, total bilirubin, IL-1β, IL-6, TNF-a, and malondialdehyde. Plasma albumin, total protein, total antioxidant capacity and glutathione peroxidase decreased post-challenge. The results were better with OH-Met than DL-Met. The increase of Met consumption, particularly as OH-Met increased piglets' growth performance during the lactation phase and the challenging period.

Mammary Protein Synthesis upon Long-Term Nutritional Restriction Was Attenuated by Oxidative-Stress-Induced Inhibition of Vacuolar H+-Adenosine Triphosphatase/Mechanistic Target of Rapamycin Complex 1 Signaling

To determine how nutritional restriction compromised milk synthesis, sows were fed 100% (control) or 76% (restricted) of the recommended feed allowance from postpartum day (PD)-1 to PD-28. In comparison to the control, more body reserves loss, increased plasma triglyceride and high-density lipoprotein cholesterol levels, and decreased plasma methionine concentrations were observed in the restricted group at PD-21. The increased plasma malondialdehyde level, decreased plasma histidine and taurine concentrations, and decreased glutathione peroxidase activity were observed at PD-28 when backfat loss further increased in the restricted group. In mammary glands, vacuolar H⁺-adenosine triphosphatase (v-ATPase), as the upstream of the mechanistic target of rapamycin (mTOR) signaling, showed decreased activity, while phosphorylation of mTOR, S6 kinase, and eukaryotic translation initiation factor 4E-binding protein 1 and β-casein abundance all decreased following feed restriction. Altogether, long-term nutrition restriction could induce progressively aggravated oxidative stress and compromise mammary protein synthesis through repression of v-ATPase/mTORC1 signaling.

Undernutrition Shapes the Gut Microbiota and Bile Acid Profile in Association with Altered Gut-Liver FXR Signaling in Weaning Pigs

Bile acids, synthesized in the liver and metabolized by microbiota, have emerged as important signaling molecules regulating immune responses and cell proliferation. However, the crosstalk among nutrition, microbiota, and bile acids remains unclear. Our study indicated that undernutrition in weaning piglets led to intestinal atrophy, increased colonic production, and systemic accumulation of lithocholic acid (LCA), deoxycholic acid (DCA), or their conjugated forms, which might be associated with decreased Lactobacillus abundance. Moreover, undernutrition led to increased portal fibroblast growth factor 19 ( FGF19) level, upregulated hepatic heterodimer partner ( SHP), and downregulated cholesterol 7a-hydroxylase ( CYP7A1) expression. The detrimental effects of DCA and LCA on proliferation and barrier function were confirmed in porcine enterocytes, whereas their roles in weaning piglets warrant further research. In summary, undernutrition in weaning piglets led to increased secondary bile acids production, which might be related to altered gut microbiome and enhanced farnesoid X receptor (FXR) signaling while CYP7A1 expression was suppressed.

Substitution of Dietary Sulfur Amino Acids by DL-2-hydroxy-4-Methylthiobutyric Acid Increases Remethylation and Decreases Transsulfuration in Weaned Piglets

BACKGROUND

DL-2-hydroxy-4-methylthiobutyric acid (DL-HMTBA), an L-methionine (L-Met) hydroxyl analogue, has been suggested to be a dietary L-Met source. How dietary DL-HMTBA compared with L-Met affects whole-body L-Met kinetics in growing individuals is unknown.

OBJECTIVES

We determined to what extent DL-HMTBA supplementation of an L-Met-deficient diet affects whole-body L-Met and L-cysteine (L-Cys) kinetics, protein synthesis (PS), and the L-Met incorporation rate in liver protein (L-MetInc) compared with L-Met and DL-Met supplementation in a piglet model.

METHODS

Forty-five, 28-d-old weaned piglets (male, German Landrace) were allocated to 4 dietary groups: L-Met-deficient diet [Control: 69% of recommended L-Met plus L-Cys supply; 0.22% standardized ileal digestible (SID) L-Met; 0.27% SID L-Cys; n = 12] and Control diet supplemented equimolarly to 100% of recommended intake with either L-Met (n = 12; LMET), DL-Met (n = 11; DLMET), or DL-HMTBA (n = 10; DLHMTBA). At 47 d of age, the piglets were infused with L-[1-13C; methyl-2H3]-Met and [3,3-2H2]-Cys to determine the kinetics and PS rates. Plasma amino acid (AA) concentrations, hepatic mRNA abundances of L-Met cycle and transsulfuration (TS) enzymes, and L-MetInc were measured.

RESULTS

During feed deprivation, L-Met kinetics did not differ between groups, and were ≤3 times higher in the fed state (P < 0.01). Remethylation (RM) was 31% and 45% higher in DLHMTBA than in DLMET and Control pigs, respectively, and the RM:transmethylation (TM) ratio was 50% higher in DLHMTBA than in LMET (P < 0.05). Furthermore, TS and the TS:TM ratio were 32% lower in DLHMTBA than in LMET (P < 0.05). L-MetInc was 42% lower in DLMET and DLHMTBA than in L-Met-deficient Control pigs, whereas plasma AA and hepatic mRNA abundances were similar among DL-HMTBA-, L-Met-, and DL-Met-supplemented pigs.

CONCLUSIONS

In piglets, DL-HMTBA compared with L-Met and DL-Met supplementation increases RM and reduces the TS rate to conserve L-Met, but all 3 Met isomers support growth at a comparable rate.

Microbial insight into dietary protein source affects intestinal function of pigs with intrauterine growth retardation

PURPOSE

Dietary protein, as important macronutrient, is vital for intestinal function and health status. We aimed to determine the effects of dietary protein source on growth performance and intestinal function of neonates with intrauterine growth retardation (IUGR) in a pig model.

METHODS

Eighteen pairs of IUGR and normal birth weight (NBW) weaned pigs were allotted to be fed starter diet containing soybean protein concentrate (SPC) or spray-dried porcine plasma (SDPP) for 2 weeks. Growth performance, antioxidant variables, intestinal morphology and absorption capability, microbiota composition and short-chain fatty acids (SCFA) were assessed.

RESULTS

IUGR led to poor growth performance, absorption capability and changes on antioxidant variables, while SDPP diet improved the growth performance, diarrhea index, intestinal morphology and antioxidant variables of IUGR or NBW pigs relative to that fed SPC diet. Importantly, SDPP diet improved bacterial diversity and increased the abundance of phylum Firmicutes, but decreased the phylum Proteobacteria in colonic digesta, associating with higher genera Lactobacillus and lower genera Escherichia-Shigella, linking to the increased concentration of SCFA.

CONCLUSIONS

Our findings indicate that IUGR impairs the growth rate, intestinal function and oxidative status of weaned pigs, which could be partly improved by SDPP diet either for IUGR or NBW pigs, associating with the better antioxidant capability, composition of microbiotas and their metabolites.

Effects of N-Acetyl-Cysteine Supplementation through Drinking Water on the Glutathione Redox Status during the Weaning Transition of Piglets

This study investigated the effect of N-acetyl-cysteine (NAC) supplementation through drinking water on animal performance and the glutathione (GSH) redox system in weaned piglets, particularly in relation to the immediate post-weaning feed intake. To this end, 168 piglets were weaned and either fed ad libitum or fasted the first two days, and either or not administered 200 mg/L NAC via the drinking water until d14 post-weaning. Next to animal performance until day 42 (d42), the GSH redox system was measured in erythrocytes, small intestinal mucosa, liver, lung, and kidney tissue at d0, d2, and d14 post-weaning. Animal performance and GSH levels were not affected by NAC, nor by fasting. Irrespective of treatment, a significant drop in GSH at d2 post-weaning was found as compared to d0, in particular in liver (−69%), distal jejunal mucosa (−72%), and lung tissue (−80%). Post-weaning changes of the GSH redox status were strongly tissue-dependent. To conclude, this research indicates that GSH redox homeostasis was largely affected in multiple organs during the weaning transition. NAC supplementation did not increase GSH levels in any tissue, not even in fasted animals, questioning the fact if cysteine is the first or only limiting factor determining the rate of GSH synthesis in the early post-weaning phase.

Mammary cell proliferation and catabolism of adipose tissues in nutrition-restricted lactating sows were associated with extracellular high glutamate levels

Background

Persistent lactation, as the result of mammary cellular anabolism and secreting function, is dependent on substantial mobilization or catabolism of body reserves under nutritional deficiency. However, little is known about the biochemical mechanisms for nutrition-restricted lactating animals to simultaneously maintain the anabolism of mammary cells while catabolism of body reserves. In present study, lactating sows with restricted feed allowance (RFA) (n = 6), 24% feed restriction compared with the control (CON) group (n = 6), were used as the nutrition-restricted model. Microdialysis and mammary venous cannulas methods were used to monitor postprandial dynamic changes of metabolites in adipose and mammary tissues.

Results

At lactation d 28, the RFA group showed higher (P < 0.05) loss of body weight and backfat than the CON group. Compared with the CON group, the adipose tissue of the RFA group had higher (P < 0.05) extracellular glutamate and insulin levels, increased (P < 0.05) lipolysis related genes (HSL and ATGL) expression, and decreased (P < 0.05) glucose transport and metabolism related genes (VAMP8, PKLR and LDHB) expression. These results indicated that under nutritional restriction, reduced insulin-mediated glucose uptake and metabolism and increased lipolysis in adipose tissues was related to extracellular high glutamate concentration. As for mammary glands, compared with the CON group, the RFA group had up-regulated (P < 0.05) expression of Notch signaling ligand (DLL3) and receptors (NOTCH2 and NOTCH4), higher (P < 0.05) extracellular glutamate concentration, while expression of cell proliferation related genes and concentrations of most metabolites in mammary veins were not different (P > 0.05) between groups. Accordingly, piglet performance and milk yield did not differ (P > 0.05) between groups. It would appear that activation of Notch signaling and adequate supply of glutamate might assist mammogenesis.

Conclusions

Mammary cell proliferation and catabolism of adipose tissues in nutrition-restricted lactating sows were associated with extracellular high glutamate levels.

Electronic supplementary material

The online version of this article (10.1186/s40104-018-0293-6) contains supplementary material, which is available to authorized users.

Energy metabolism in the intestinal crypt epithelial cells of piglets during the suckling period

We tested the hypothesis that energy metabolism in the intestinal crypt epithelial cells of piglets changes during the suckling period. The experiment began with 24 piglets from 8 litters (3 piglets per litter). One piglet from each litter was randomly selected and euthanized at 7, 14, or 21 d of age, respectively. Crypt cells were isolated from the mid-jejunum and protein synthesis was analyzed using isobaric tags for relative and absolute quantification. The production of proteins related to glycolysis was mainly decreased from Days 7 to 14 before increasing up to Day 21. Synthesis of proteins involved in fatty acids, amino acids (glutamate and glutamine), and citrate cycle metabolism was generally down-regulated for samples collected on Days 14 and 21 when compared with levels on Day 7. These results indicate that energy metabolism in the intestinal crypt epithelial cells changes during the suckling period. Furthermore, this pattern of metabolism varies among glucose, fatty acids, and amino acids. Therefore, these findings may be useful in efforts to regulate the intestinal development of piglets.

Dietary nucleotides supplementation during the suckling period improves the antioxidative ability of neonates with intrauterine growth retardation when using a pig model

The aim of the present study was to investigate the effect of dietary nucleotides supplementation on the antioxidant status of piglets affected by intrauterine growth retardation (IUGR). Fourteen pairs of normal birth weight (NBW) and IUGR piglets were fed either a control diet (CON) or a nucleotides supplementation diet (NT) from 7 d of age to 28 d postnatal. Blood, liver and jejunum samples were collected at the end of the study. The results showed that IUGR piglets had decreased (P < 0.05) concentrations of plasma total antioxidant capability (T-AOC) and total superoxide dismutase (T-SOD), gene expressions of hepatic cytoplasmic copper/zinc SOD (CuZnSOD) and PPARγ coactivator-1α (PGC-1α) and jejunal glutathione peroxidase (GP_X) and extracellular superoxide dismutase (ESOD), accordingly, there was markedly higher (P < 0.05) plasma malondialdehyde (MDA) and hepatic and jejunal mitochondria DNA content in the IUGR piglets relative to NBW piglets. Regardless of body weight, dietary NT supplementation significantly increased (P < 0.05) plasma concentrations of T-AOC, T-SOD, CuZnSOD, GP_X and the ratio of reduced glutathione to oxidized glutathione, hepatic T-SOD, GP_X and mitochondria DNA content, while hepatic MDA concentration was markedly decreased (P < 0.05) 19.1% by NT diet. Furthermore, the gene expressions of hepatic glutathione reductase, CuZnSOD, nuclear erythroid 2-related factor 2, PGC-1α and nuclear respiratory factor-1 (NRF-1) and jejunal GP_X, CuZnSOD, ESOD and NRF-1 were significantly increased (P < 0.05) by NT diet, whereas the gene expression of Kelch-like ECH-associated protein 1 were markedly decreased (P < 0.05) compared with that of piglets fed with CON diet. These results indicate that dietary NT supplementation prevents the effect of IUGR on oxidative status and mitochondria DNA damage through improving the non-enzymatic and enzymatic antioxidant capacities as well as mitochondria biogenesis of piglets.

The aim of the present study was to investigate the effect of dietary nucleotides supplementation on the antioxidant status of piglets affected by intrauterine growth retardation (IUGR).

mTORC1 signaling-associated protein synthesis in porcine mammary glands was regulated by the local available methionine depending on methionine sources

Mechanistic target of rapamycin complex1 (mTORC1) activation and protein synthesis varied with methionine sources; however, the related mechanisms are largely unknown. Porcine mammary epithelial cells (PMEC) and mammary tissue slices (MTS) were used to test whether methionine precursors differ in providing the available methionine and thus differ in mTORC1 signaling-associated protein synthesis. PMEC with methionine deprivation for 8 h and MTS from lactating sows were cultured for 24 and 2 h, respectively, with treatment media without methionine (negative control, NC) or supplemented with 0.6 mM (for PMEC) and 0.1 mM (for MTS) of L-methionine (L-MET), D-methionine (D-MET), DL-2-hydroxy-4-(methylthio) butyric acid (HMTBA), or keto-methyl(thio)butanoic acid (KMB). The measurements included: phosphorylation of mTORC1 signaling, fractional protein synthesis rate (FSR), amino acids (AA) profile, and enzyme activities. Compared with the NC treatment, activated mTORC1 signaling as manifested by higher (P < 0.05) protein abundance of phosphorylated-S6 Kinase 1 (P-S6K1) and phosphorylated-4E-binding Protein 1 (P-4E-BP1) in PMEC and MTS, and increased protein synthesis as indicated by higher (P < 0.05) FSR in MTS occurred in L-MET and HMTBA treatments rather than in D-MET treatment. Compared with the NC treatment, methionine concentration and ratio of methionine to lysine in MTS increased (P < 0.05) in L-MET and HMTBA treatments but not in D-MET treatment, and activities of enzymes responsible for conversion of D-MET and HMTBA to keto-methionine in mammary tissues were about 10 and 50%, respectively, of that in liver. Taken together, mTORC1 signaling-associated protein synthesis in porcine mammary glands was regulated by the local available methionine depending on methionine sources.

Short-term dietary methionine supplementation affects one-carbon metabolism and DNA methylation in the mouse gut and leads to altered microbiome profiles, barrier function, gene expression and histomorphology

BACKGROUND

Methionine, a central molecule in one-carbon metabolism, is an essential amino acid required for normal growth and development. Despite its importance to biological systems, methionine is toxic when administered at supra-physiological levels. The aim of this study was to investigate the effects of short-term methionine dietary modulation on the proximal jejunum, the section of the gut specifically responsible for amino acid absorption, in a mouse model. Eight-week-old CBA/J male mice were fed methionine-adequate (MAD; 6.5 g/kg) or methionine-supplemented (MSD; 19.5 g/kg) diets for 3.5 or 6 days (average food intake 100 g/kg body weight). The study design was developed in order to address the short-term effects of the methionine supplementation that corresponds to methionine dietary intake in Western populations. Biochemical indices in the blood as well as metabolic, epigenetic, transcriptomic, metagenomic, and histomorphological parameters in the gut were evaluated.

RESULTS

By day 6, feeding mice with MSD (protein intake <10% different from MAD) resulted in increased plasma (2.3-fold; p < 0.054), but decreased proximal jejunum methionine concentrations (2.2-fold; p < 0.05) independently of the expression of neutral amino acid transporters. MSD has also caused small bowel bacteria colonization, increased the abundance of pathogenic bacterial species Burkholderiales and decreased the gene expression of the intestinal transmembrane proteins-Cldn8 (0.18-fold, p < 0.05), Cldn9 (0.24-fold, p < 0.01) and Cldn10 (0.05-fold, p < 0.05). Feeding MSD led to substantial histomorphological alterations in the proximal jejunum exhibited as a trend towards decreased plasma citrulline concentrations (1.8-fold, p < 0.07), as well as loss of crypt depth (by 28%, p < 0.05) and mucosal surface (by 20%, p < 0.001).

CONCLUSIONS

Together, these changes indicate that short-term feeding of MSD substantially alters the normal gut physiology. These effects may contribute to the pathogenesis of intestinal inflammatory diseases and/or sensitize the gut to exposure to other stressors.

Dietary supplementation with tributyrin prevented weaned pigs from growth retardation and lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation

Weanling pigs, with an underdeveloped intestine and immature immune system, are usually subjected to depressed feed intake, growth retardation, and postweaning diarrhea. The aim of this study was to determine 1) the growth response of weaned pigs to supplemental tributyrin (TB) and 2) the potential effects and mechanisms of TB in modulating immune responses of lipopolysaccharide (LPS)-challenged piglets. A total of 240 piglets (Duroc × Large White × Landrace) were weaned at 21 d of age to a control (basal diet), supplemented with antibiotics (AB; +AB), supplemented with TB (+TB), or with supplemental AB and TB (+AB+TB) diets, with 10 replicate pens (6 piglets/pen) per diet. At 49 d of age, male pigs from the control and +TB groups were intraperitoneally injected with LPS (25 μg/kg BW) or saline ( = 6) and sacrificed at 4 h after injection to collect blood, intestine, and digesta samples for biochemical analysis. There were higher ( < 0.05) feed intake and lower ( < 0.05) percentage of negative growth piglets in the +TB groups than in the control group during the first week after weaning. For piglets without LPS challenge, there were higher ( < 0.05) ileal fibroblast growth factor 19 () mRNA abundance and total bile acid concentrations in the +TB groups than in the control group, whereas downregulated ( < 0.05) expression was observed in the +TB groups after LPS challenge. Lipopolysaccharide challenge in the control group increased ( < 0.05) plasma tumor necrosis factor α and IL-6 concentrations and colonic amount and decreased ( < 0.05) colonic goblet cells and colonic and cecal acetate concentrations, with no differences ( > 0.05) observed between +TB groups following LPS challenge. Taken together, dietary supplementation with TB prevented growth retardation through stimulating the appetite of weaned pigs and protected piglets against lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation.

Transfer of β-hydroxy-β-methylbutyrate from sows to their offspring and its impact on muscle fiber type transformation and performance in pigs

Background

Previous studies suggested that supplementation of lactating sows with β-hydroxy-β-methylbutyrate (HMB) could improve the performance of weaning pigs, but there were little information in the muscle fiber type transformation of the offspring and the subsequent performance in pigs from weaning through finishing in response to maternal HMB consumption. The purpose of this study was to determine the effect of supplementing lactating sows with HMB on skeletal muscle fiber type transformation and growth of the offspring during d 28 and 180 after birth. A total of 20 sows according to their body weight were divided into the control (CON, n = 10) or HMB groups (HMB, n = 10). Sows in the HMB group were supplemented with β-hydroxy-β-methylbutyrate calcium (HMB-Ca) 2 g /kg feed during d 1 to 27 of lactation. After weaning, 48 mixed sex piglets were blocked by sow treatment and fed standard diets for post-weaning, growing, finishing periods. Growth performance was recorded during d 28 to 180 after birth. Pigs were slaughtered on d 28 (n = 6/treatment) and 180 (n = 6/treatment) postnatal, and the longissimus dorsi (LD) was collected, respectively.

Results

The HMB-fed sows during lactation showed increased HMB concentration (P < 0.05) in milk and LD of weaning piglets (P < 0.05). In addition, offsprings in HMB group had a higher finishing BW and lean percentage than did pigs in CON group (P < 0.05), meanwhile, compared with pigs from sows fed the CON diet, pigs from sows fed HMB diet showed higher type II muscle fiber cross-sectional area (CSA), elevated myosin heavy chain (MyHC) IIb and Sox6 mRNA, and fast-MyHC protein levels in LD (P < 0.05).

Conclusions

HMB supplemented to sow diets throughout lactation increases the levels of HMB in maternal milk and skeletal muscle of pigs during d 28 after birth and promotes subsequent performance of pigs between d 28 and 180 of age by enhancing glycolytic muscle fiber transformation.

Increased maternal consumption of methionine as its hydroxyl analog promoted neonatal intestinal growth without compromising maternal energy homeostasis

BACKGROUND

To determine responses of neonatal intestine to maternal increased consumption of DL-methionine (DLM) or DL-2-hydroxy-4-methylthiobutanoic acid (HMTBA), eighteen primiparous sows (Landrace × Yorkshire) were allocated based on body weight and backfat thickness to the control, DLM and HMTBA groups (n = 6), with the nutritional treatments introduced from postpartum d0 to d14.

RESULTS

The DLM-fed sows showed negative energy balance manifested by lost bodyweight, lower plasma glucose, subdued tricarboxylic acid cycle, and increased plasma lipid metabolites levels. Both villus height and ratio of villus height to crypt depth averaged across the small intestine of piglets were higher in the DLM and HMTBA groups than in the control group. Piglet jejunal oxidized glutathione concentration and ratio of oxidized to reduced glutathione were lower in the HMTBA group than in the DLM and control groups. However, piglet jejunal aminopeptidase A, carnitine transporter 2 and IGF-II precursor mRNA abundances were higher in the DLM group than in the HMTBA and control groups.

CONCLUSION

Increasing maternal consumption of methionine as DLM and HMTBA promoted neonatal intestinal growth by increasing morphological development or up-regulating expression of genes responsible for nutrient metabolism. And increasing maternal consumption of HMTBA promoted neonatal intestinal antioxidant capacity without compromising maternal energy homeostasis during early lactation.

Dietary supplementation with β-hydroxy-β-methylbutyrate calcium during the early postnatal period accelerates skeletal muscle fibre growth and maturity in intra-uterine growth-retarded and normal-birth-weight piglets

Intra-uterine growth restriction (IUGR) impairs postnatal growth and skeletal muscle development in neonatal infants. This study evaluated whether dietary β-hydroxy-β-methylbutyrate Ca (HMB-Ca) supplementation during the early postnatal period could improve muscle growth in IUGR neonates using piglets as a model. A total of twelve pairs of IUGR and normal-birth-weight (NBW) male piglets with average initial weights (1·85 (sem 0·36) and 2·51 (sem 0·39) kg, respectively) were randomly allotted to groups that received milk-based diets (CON) or milk-based diets supplemented with 800 mg/kg HMB-Ca (HMB) during days 7-28 after birth. Blood and longissimus dorsi (LD) samples were collected and analysed for plasma amino acid content, fibre morphology and the expression of genes related to muscle development. The results indicate that, regardless of diet, IUGR piglets had a significantly decreased average daily weight gain (ADG) compared with that of NBW piglets (P<0·05). However, IUGR piglets fed HMB-Ca had a net weight and ADG similar to that of NBW piglets fed the CON diet. Irrespective of body weight (BW), HMB-Ca supplementation markedly increased the type II fibre cross-sectional area and the mRNA expression of mammalian target of rapamycin (mTOR), insulin-like growth factor-1 and myosin heavy-chain isoform IIb in the LD of piglets (P<0·05). Moreover, there was a significant interaction between the effects of BW and HMB on mTOR expression in the LD (P<0·05). In conclusion, HMB-Ca supplementation during the early postnatal period could improve skeletal muscle growth and maturity by accelerating fast-twitch glycolytic fibre development in piglets.

Rearing conditions affected responses of weaned pigs to organic acids showing a positive effect on digestibility, microflora and immunity

Three experiments were conducted to assess the response of weaned pigs to organic acid SF3, which contains 34% calcium formate, 16% calcium lactate, 7% citric acid and 13% medium chain fatty acids. Dietary treatments had no effect on growth performance of piglets (21-day weaning) fed the commercial prestart diet for 1 week before receiving the experimental diets supplemented with SF3 at 0, 3 or 5 g/kg diet (Exp. 1), whereas diarrhea frequency averaged across a week was decreased by SF3 supplementation (5 g/kg diet) in piglets fed the experimental diets immediately after weaning (Exp. 2). In Exp. 3, piglets (28-day weaning) were fed the control (containing pure colistin sulfate and enramycin, respectively, at 20 mg/kg diet) for 1 week and then were fed the control or SF3-supplemented (5 g/kg diet) diet for 2 weeks. The SF3-fed piglets had greater apparent ileal digestibility of calcium and dry matter, while also demonstrating greater overall gross energy, up-regulated jejunal expression of sodium-glucose cotransporter-1 and transforming growth factor-β, down-regulated jejunal expression of tumor necrosis factor (TNF)-α, higher ileal Lactobacillus, with lower total bacteria content, lower plasma TNF-α but higher IgG levels than the control-fed piglets. Collectively, SF3 consumption improved diarrhea resistance of weaned pigs by improving nutrient digestibility, piglet immunity and intestinal bacteria profile. © 2016 Japanese Society of Animal Science.

L-Cysteine metabolism and its nutritional implications

L-Cysteine is a nutritionally semiessential amino acid and is present mainly in the form of L-cystine in the extracellular space. With the help of a transport system, extracellular L-cystine crosses the plasma membrane and is reduced to L-cysteine within cells by thioredoxin and reduced glutathione (GSH). Intracellular L-cysteine plays an important role in cellular homeostasis as a precursor for protein synthesis, and for production of GSH, hydrogen sulfide (H(2)S), and taurine. L-Cysteine-dependent synthesis of GSH has been investigated in many pathological conditions, while the pathway for L-cysteine metabolism to form H(2)S has received little attention with regard to prevention and treatment of disease in humans. The main objective of this review is to highlight the metabolic pathways of L-cysteine catabolism to GSH, H(2)S, and taurine, with special emphasis on therapeutic and nutritional use of L-cysteine to improve the health and well-being of animals and humans.

Effects of Dietary Supplementation of β-hydroxy-β-methylbutyrate on Sow Performance and mRNA Expression of Myogenic Markers in Skeletal Muscle of Neonatal Piglets

The effects of dietary β-hydroxy-β-methylbutyrate (HMB) supplementation during gestation on reproductive performance of sows and the mRNA expression of myogenic markers in skeletal muscle of neonatal pigs were determined. At day 35 of gestation, a total of 20 sows (Landrace × Yorkshire, at third parity) were randomly assigned to two groups, with each group receiving either a basal diet or the same diet supplemented with 4 g/day β-hydroxy-β-methylbutyrate calcium (HMB-Ca) until parturition. At parturition, the total and live litter size were not markedly different between treatments, however, the sows fed HMB diet had a decreased rate of stillborn piglets compared with the sows fed the control (CON) diets (p < 0.05). In addition, piglets from the sows fed HMB diet tended to have an increased birth weight (p = 0.08), and a reduced rate of low birth weight piglets (p = 0.05) compared with piglets from the CON sows. Nevertheless, lower feed intake during lactation was observed in the sows fed the HMB diet compared with those on the CON diet (p < 0.01). The relative weights of the longissimus dorsi (LD) and semitendinosus (ST) muscle were higher (p < 0.05) in neonatal pigs from the HMB than the CON sows. Furthermore, maternal HMB treatment increased the mRNA levels of the myogenic genes, including muscle regulatory factor-4 (MRF4, p < 0.05), myogenic differentiation factor (MyoD) and insulin-like growth factor-1 (IGF-1, p < 0.01). In conclusion, dietary HMB supplementation to sows at 4 g/day from day 35 of gestation to term significantly improves pregnancy outcomes and increases the expression of myogenic genes in skeletal muscle of neonatal piglets, but reduces feed intake of sows during lactation.

Comparison of methionine sources around requirement levels using a methionine efficacy method in 0 to 28 day old broilers

The addition of methionine in the poultry feed industry is still facing the relative efficacy dilemma between DL-methionine (DLM) and hydroxy-methionine (HMTBA). The aim of this study was to compare the effect of dietary DLM and HMTBA on broiler performance at different levels of total sulfur amino acids (TSAA). The treatments consisted of a basal diet without methionine addition, and 4 increasing methionine doses for both sources resulting in TSAA/Lysine ratios from 0.62 to 0.73 in the starter phase and 0.59 to 0.82 in the grower phase. The comparison of product performance was performed by three-way ANOVA analysis and by methionine efficacy calculation as an alternative method of comparison. Growth results obtained during the starter phase with the different methionine supplementations did not show significant growth responses to TSAA levels, indicating a lower methionine requirement in the starter phase than currently assumed. However, a significant methionine dose effect was obtained for the period 10 to 28 day of age and for the entire growth period of 0 to 28 day of age. Excepting a significant gender effect, the statistical analysis did not allow for the discrimination of methionine sources, and no interaction between source and dose level was observed up to 28 days of age. A significant interaction between source and dose level was observed for methionine efficacy for the grower phase, and the total growth period showed better HMTBA efficacy at higher TSAA value. The exponential model fitted to each methionine source for body weight response depending on methionine intake or for feed conversion ratio (FCR) depending on methionine doses did not allow the methionine sources to be distinguished. Altogether, these results conclude that methionine sources lead to similar performances response when compared at TSAA values around the broiler requirement level. These results also showed that at TSAA values above requirement, HMTBA had a better methionine efficacy value than DLM, caused by the different properties of that molecule, whereas below the TSAA requirement levels, the opposite was observed in females.

Níveis de metionina + cistina para leitões dos 6 aos 16 kg submetidos a diferentes graus de ativação do sistema imune

RESUMO O experimento foi realizado com o objetivo de avaliar os efeitos dos níveis de metionina + cistina da dieta sobre o desempenho, características de carcaça e a resposta imunológica de leitões recém-desmamados. Foram utilizados 360 leitões, 180 machos e 180 fêmeas, desmamados com idade média de 18,8 dias e peso inicial de 5,43 ± 1,17kg. Foi utilizado o delineamento de blocos ao acaso em esquema fatorial 5x2, com cinco níveis de metionina + cistina total (0,70; 0,77; 0,85; 0,93 e 1,01%) e duas formas de ativação do sistema imune (vacinados e não vacinados), quatro repetições e nove animais por unidade experimental. Não houve interação entre os níveis de metionina+cistina e o grau de ativação do sistema imune dos animais para todos os parâmetros avaliados. A ativação do sistema imune reduziu em 7% o consumo de ração e em 5% no ganho de peso diário dos animais. Os níveis de metionina + cistina melhoraram de forma linear a conversão alimentar e a deposição de proteína diária na carcaça à medida que o nível dos aminoácidos sulfurados aumentou nas dietas. Suínos dos seis aos 16kg, independente da ativação do sistema imune, exigem 0,90% de metionina + cistina total, o que corresponde a um consumo diário de metionina + cistina de 4,44 g/dia e uma relação de 58% metionina+cistina:lisina.