The Combined Use of Medium- and Short-Chain Fatty Acids Improves the Pregnancy Outcomes of Sows by Enhancing Ovarian Steroidogenesis and Endometrial Receptivity.

Fatty acids play important roles in maintaining ovarian steroidogenesis and endometrial receptivity. Porcine primary ovarian granulosa cells (PGCs) and endometrial epithelial cells (PEECs) were treated with or without medium- and short-chain fatty acids (MSFAs) for 24 h. The mRNA abundance of genes was detected by fluorescence quantitative PCR. The hormone levels in the PGCs supernatant and the rate of adhesion of porcine trophoblast cells (pTrs) to PEECs were measured. Sows were fed diets with or without MSFAs supplementation during early gestation. The fecal and vaginal microbiomes were identified using 16S sequencing. Reproductive performance was recorded at parturition. MSFAs increased the mRNA abundance of genes involved in steroidogenesis, luteinization in PGCs and endometrial receptivity in PEECs (p < 0.05). The estrogen level in the PGC supernatant and the rate of adhesion increased (p < 0.05). Dietary supplementation with MSFAs increased serum estrogen levels and the total number of live piglets per litter (p < 0.01). Moreover, MSFAs reduced the fecal Trueperella abundance and vaginal Escherichia-Shigella and Clostridium_sensu_stricto_1 abundance. These data revealed that MSFAs improved pregnancy outcomes in sows by enhancing ovarian steroidogenesis and endometrial receptivity while limiting the abundance of several intestinal and vaginal pathogens at early stages of pregnancy.

Effects of dietary crude protein level and N-carbamylglutamate supplementation on nutrient digestibility and digestive enzyme activity of jejunum in growing pigs.

Three experiments were conducted to investigate the effects of dietary crude protein (CP) level and N-carbamylglutamate (NCG) supplementation on apparent total tract digestibility (ATTD) and ileal digestibility of nutrients and digestive enzyme activity of jejunum in growing pigs. In experiment 1, 10 Duroc × Landrace × Yorkshire barrows (initial BW: 48.7 kg) were allotted to a three-period switchback design with five experimental diets and two replicate pigs per diet in each period. Diets were categorized as high CP (HP, 18% CP), moderate low CP (MLP, 15% CP), very low CP (VLP, 12% CP), and MLP and VLP with 0.1% NCG supplementation. Feces and urine were collected from day 6 to day 11 after a 5-d adaptation period. The DE, ME, and ATTD of GE, OM, CP, NDF, ADF, and P decreased (P < 0.01) with a reduction of dietary CP, but no effect of dietary treatments on pig daily N retention was detected. The NCG supplementation increased (P < 0.01) DE and ATTD of ADF of the VLP diet. In experiment 2, 10 jejunal-cannulated Duroc × Landrace × Yorkshire barrows (initial BW: 44.5 kg) were fed five diets for three periods as experiment 1. Jejunal fluid was collected on days 6 and 8 after a 5-d adaptation period. The digestive enzymes activity was not affected by dietary CP level, except for α-amylase, for which there was a decrease (P < 0.01) in pigs fed VLP diets compared to HP and MLP diets. In experiment 3, 12 ileal-cannulated Duroc × Landrace × Yorkshire barrows (initial BW: 46.7 kg) were allotted to a three-period switchback design with six diets and two replicate pigs per diet in each period. The six experimental diets consisted of five experimental diets as experiment 1 and one N-free diet. Ileal digesta was collected from day 6 to day 8 after a 5-d adaptation period. Results indicated that apparent ileal digestibility (AID) of CP and P and ileal digestibility of Arg, His, Ile, Leu, Phe, and all dispensable AA, except Pro, decreased (P < 0.01) in pigs fed VLP diet compared to HP and MLP diets, but AID of GE, OM, EE, NDF, and ADF were not affected. The supplementation of NCG in the VLP diet increased (P < 0.01) the AID of CP and ileal digestibility of Arg, His, Leu, Phe, Val, Ser, and Tyr. In conclusion, reducing dietary CP level decreased nutrient digestibility, but improved the efficiency of dietary N utilization and reduced N emission. Moderate reduction of dietary CP level had a minimal effect on nutrient digestibility and digestive enzyme activity. Additionally, NCG supplementation plays a beneficial effect on nutrient digestion only if the dietary CP level is extremely lowered.

Crystalline amino acids supplementation improves the performance and carcass traits in late-finishing gilts fed low-protein diets.

This study investigated the effects of amino acids (AA) supplementation in low-crude protein (CP) diets on the growth performance and carcass characteristics in late-finishing gilts. Ninety gilts (93.8 ± 5.5 kg) were randomly allotted to one of the five diets which consisted of a normal-CP (137 g/kg) or four low-CP (105 g/kg) diets for 28 days. The low-CP diets were supplemented with lysine + threonine + methionine (LCM), LCM + tryptophan (LCT), LCT + valine (LCV) or LCV + isoleucine (LCI), respectively. Non-significant difference in average daily gain (ADG) was obtained in gilts receiving the control and LCV diet, which was higher than that of gilts fed the LCM diet (p < .05). The additions of crystalline AA in the low-CP diet resulted in the improvements in ADG (linear and quadratic effect, p < .05) and fat-free lean gain (quadratic effect, p < .05) and influenced the valine concentration (linear and quadratic effect, p < .05) and proportion of saturated fatty acid (linear effect, p < .05) in longissimus muscle. The results indicated that the valine supplementation could further improve the performance in 94 to 118 kg gilts fed the 105 g/kg CP diet.

Isoleucine attenuates infection induced by E. coli challenge through the modulation of intestinal endogenous antimicrobial peptide expression and the inhibition of the increase in plasma endotoxin and IL-6 in weaned pigs.

Enteric infection is a major cause of morbidity and mortality in both humans and animals worldwide. Immunotherapy against intestinal infection is a well-known alternative to the antibiotic strategy. Herein, we demonstrated that isoleucine significantly suppressed the multiplication of E. coli in the presence of IPEC-J2 cells. Isoleucine supplementation enhanced the concentrations of total plasma protein and IgA in pigs compared to the alanine control diet, while inhibiting the increase in plasma endotoxin and IL-6 contents induced by E. coli challenge. A significant interaction between the E. coli challenge and the diet treatment was found in the red blood cell volume. Isoleucine improved the expression of porcine ß-defensin-1 (pBD-1), pBD-2, pBD-3, pBD-114 and pBD-129 in the jejunum and ileum of pigs with or without E. coli challenge. Conclusively, isoleucine attenuated the infection caused by the E. coli challenge possibly through increasing the intestinal ß-defensin expression and inhibiting the increase in plasma endotoxin and IL-6 in weaned pigs.

Maternal short and medium chain fatty acids supply during early pregnancy improves embryo survival through enhancing progesterone synthesis in rats.

Exploring strategies to prevent miscarriage in women or early pregnancy loss in mammals is of great importance. Manipulating maternal lipid metabolism to maintain sufficient progesterone level is an effective way. To investigated the embryo loss and progesterone synthesis impacts of short and medium chain fatty acids on the lipid metabolism, pregnancy outcome and embryo implantation were investigated in rats fed the pregnancy diets supplemented without or with 0.1% sodium butyrate (SB), 0.1% sodium hexanoate (SH), or 0.1% sodium caprylate (SC) during the entire pregnancy and early pregnancy, respectively, followed with evaluation of potential mechanisms. Maternal SB, SH, or SC supply significantly improved live litter size and embryo implantation in rats. Serum progesterone, arachidonic acid, and phospholipid metabolites levels were significantly increased in response to maternal SB, SH, and SC supply. The expression of key genes involved in ovarian steroidogenesis and granulosa cell luteinization were elevated in ovaries and primary cultured granulosa cells, including cluster of differentiation 36 (CD36), steroidogenic acute regulatory protein (StAR), and cholesterol side-chain cleavage enzyme (CYP11A1). Additionally, the expression of lysophosphatidic acid receptor 3 (LPA3) and cyclooxygenase-2 (COX2) related with phospholipid metabolism were enhanced in uterus in vivo and in in vitro cultured uterine tissue. In conclusion, maternal SB, SH and SC supply reduced early pregnancy loss through modulating maternal phospholipid metabolism and ovarian progesterone synthesis in rats. Our results have important implications that short or medium chain fatty acids have the potential to prevent miscarriage in women or early pregnancy loss in mammals.

Effects of L-lysine·H2SO4 product on the intestinal morphology and liver pathology using broiler model.

BACKGROUND: Lysine is used widely in livestock production due to the shortage of feed protein resources. L-lysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus. However, there are few articles about L-lysine·H2SO4 product regarding intestinal morphology and liver pathology of broiler chickens. In this article, we focus on the absorption and metabolism of L-lysine·H2SO4 revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H2SO4. METHODS: To evaluate the tolerance of broilers for L-lysine·H2SO4, 240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0, 1%, 4%, 7% or 10% L-lysine·H2SO4 (L-lysine content = 55%). RESULTS: Supplementation of 1% L-lysine·H2SO4 in the diet had no negative effects. However, 4%, 7% or 10% L-lysine·H2SO4 supplementation produced negative responses on broiler performance, carcass characteristics, blood biochemistry, and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet. CONCLUSION: Our results show that supplementation with 1% L-lysine·H2SO4 had no negative effects on performance, carcass characteristics, blood biochemistry, intestinal morphology and liver pathology in broilers, but supplementation with 4%, 7% or 10% L-lysine·H2SO4 produced a negative response, particularly with respect to intestinal morphology and liver pathology.

Dietary modulation of endogenous host defense peptide synthesis as an alternative approach to in-feed antibiotics.

Traditionally, antibiotics are included in animal feed at subtherapeutic levels for growth promotion and disease prevention. However, recent links between in-feed antibiotics and a rise in antibiotic-resistant pathogens have led to a ban of all antibiotics in livestock production by the European Union in January 2006 and a removal of medically important antibiotics in animal feeds in the United States in January 2017. An urgent need arises for antibiotic alternatives capable of maintaining animal health and productivity without triggering antimicrobial resistance. Host defense peptides (HDP) are a critical component of the animal innate immune system with direct antimicrobial and immunomodulatory activities. While in-feed supplementation of recombinant or synthetic HDP appears to be effective in maintaining animal performance and alleviating clinical symptoms in the context of disease, dietary modulation of the synthesis of endogenous host defense peptides has emerged as a cost-effective, antibiotic-alternative approach to disease control and prevention. Several different classes of small-molecule compounds have been found capable of promoting HDP synthesis. Among the most efficacious compounds are butyrate and vitamin D. Moreover, butyrate and vitamin D synergize with each other in enhancing HDP synthesis. This review will focus on the regulation of HDP synthesis by butyrate and vitamin D in humans, chickens, pigs, and cattle and argue for potential application of HDP-inducing compounds in antibiotic-free livestock production.

Maternal N-Carbamylglutamate Supply during Early Pregnancy Enhanced Pregnancy Outcomes in Sows through Modulations of Targeted Genes and Metabolism Pathways.

Reducing pregnancy loss is important for improving reproductive efficiency for both human and mammalian animals. Our previous study demonstrates that maternal N-carbamylglutamate (NCG) supply during early pregnancy enhances embryonic survival in gilts. However, whether maternal NCG supply improves the pregnancy outcomes is still not known. Here we found maternal NCG supply during early pregnancy in sows significantly increased the numbers of total piglets born alive per litter ( P < 0.05) and significantly changed the levels of metabolites in amniotic fluid and serum involved in metabolism of energy, lipid, and glutathione and immunological regulation. The expression of endometrial progesterone receptor membrane component 1 (PGRMC1) was significantly increased by NCG supplementation ( P < 0.05) as well as the expression of PGRMC1, endothelial nitric oxide synthesases (eNOS), and lamin A/C in fetuses and placentae ( P < 0.05). Among the NCG-associated amino acids, arginine and glutamine, markedly increased PGRMC1 and eNOS expression in porcine trophectoderm cells ( P < 0.05), whereas glutamate could stimulate the expression of vimentin and lamin A/C in porcine trophectoderm (pTr) cells ( P < 0.05) and proline stimulated lamin A/C expression ( P < 0.05). Collectively, these data reveal the mechanisms of NCG in reducing early embryo loss. These findings have important implications that NCG has great potential to improve pregnancy outcomes in human and mammalian animals.

Valine Supplementation in a Reduced Protein Diet Regulates Growth Performance Partially through Modulation of Plasma Amino Acids Profile, Metabolic Responses, Endocrine, and Neural Factors in Piglets.

The objective of this study was to investigate whether valine (Val) supplementation in a reduced protein (RP) diet regulates growth performance associated with the changes in plasma amino acids (AAs) profile, metabolism, endocrine, and neural system in piglets. Piglets or piglets with a catheter in the precaval vein were randomly assigned to two treatments, including two RP diets with standardized ileal digestible (SID) Val:Lysine (Lys) ratio of 0.45 and 0.65, respectively. The results indicated that piglets in the higher Val:Lys ratio treatment had higher average daily feed intake (ADFI) ( P < 0.001), average daily gain (ADG) ( P = 0.001), feed conversion ratio (FCR) ( P = 0.004), lower plasma urea nitrogen ( P = 0.032), expression of gastric cholecystokinin (CCK), and hypothalamic pro-opiomelanocortin (POMC). Plasma AAs profiles including postprandial plasma essential AAs (EAAs) profile and in serum, muscle, and liver involved in metabolism of AAs and fatty acids were significantly different between two treatments. In conclusion, Val influenced growth performance associated with metabolism of AAs and fatty acids and both endocrine and neural system in piglets.

Dietary N-Carbamylglutamate Supplementation in a Reduced Protein Diet Affects Carcass Traits and the Profile of Muscle Amino Acids and Fatty Acids in Finishing Pigs.

The aim of this study was to investigate whether dietary N-carbamylglutamate (NCG) supplementation in a reduced protein diet affected carcass traits and meat quality in finishing pigs. A total of 120 gilts were randomly assigned to one of four treatments for 40 days, including a standard protein diet (SP), a reduced protein diet supplemented with 1.7% l-alanine (RP + Ala), a reduced protein diet supplemented with 1.0% l-arginine (RP + Arg), and a reduced protein diet supplemented with 0.1% NCG and 1.7% l-alanine (RP + NCG). NCG supplementation increased the endogenous synthesis of l-arginine. The RP + NCG diet significantly increased the loin eye area (p < 0.05) and tended to decrease the 10th rib fat depth (p = 0.08). NCG supplementation in a reduced protein diet was effective to produce functional pork with a high content of leucine (p < 0.05). The composition of several ω-6 and ω-3 polyunsaturated fatty acids (PUFAs) but not the ratio of ω-6/ω-3 PUFAs in muscles was altered in finishing pigs with dietary NCG supplementation. In conclusion, the RP + NCG diet is effective to increase the longissimus dorsi muscle area, decrease back fat accretion, and produce functional pork with a high content of leucine but without a negative impact on the muscle fatty acid profile in finishing pigs.

Novel metabolic and physiological functions of branched chain amino acids: a review.

It is widely known that branched chain amino acids (BCAA) are not only elementary components for building muscle tissue but also participate in increasing protein synthesis in animals and humans. BCAA (isoleucine, leucine and valine) regulate many key signaling pathways, the most classic of which is the activation of the mTOR signaling pathway. This signaling pathway connects many diverse physiological and metabolic roles. Recent years have witnessed many striking developments in determining the novel functions of BCAA including: (1) Insufficient or excessive levels of BCAA in the diet enhances lipolysis. (2) BCAA, especially isoleucine, play a major role in enhancing glucose consumption and utilization by up-regulating intestinal and muscular glucose transporters. (3) Supplementation of leucine in the diet enhances meat quality in finishing pigs. (4) BCAA are beneficial for mammary health, milk quality and embryo growth. (5) BCAA enhance intestinal development, intestinal amino acid transportation and mucin production. (6) BCAA participate in up-regulating innate and adaptive immune responses. In addition, abnormally elevated BCAA levels in the blood (decreased BCAA catabolism) are a good biomarker for the early detection of obesity, diabetes and other metabolic diseases. This review will provide some insights into these novel metabolic and physiological functions of BCAA.

Effects of isoleucine on glucose uptake through the enhancement of muscular membrane concentrations of GLUT1 and GLUT4 and intestinal membrane concentrations of Na+/glucose co-transporter 1 (SGLT-1) and GLUT2.

Knowledge of regulation of glucose transport contributes to our understanding of whole-body glucose homoeostasis and human metabolic diseases. Isoleucine has been reported to participate in regulation of glucose levels in many studies; therefore, this study was designed to examine the effect of isoleucine on intestinal and muscular GLUT expressions. In an animal experiment, muscular GLUT and intestinal GLUT were determined in weaning pigs fed control or isoleucine-supplemented diets. Supplementation of isoleucine in the diet significantly increased piglet average daily gain, enhanced GLUT1 expression in red muscle and GLUT4 expression in red muscle, white muscle and intermediate muscle (P<0·05). In additional, expressions of Na+/glucose co-transporter 1 and GLUT2 were up-regulated in the small intestine when pigs were fed isoleucine-supplemented diets (P<0·05). C2C12 cells were used to examine the expressions of muscular GLUT and glucose uptake in vitro. In C2C12 cells supplemented with isoleucine in the medium, cellular 2-deoxyglucose uptake was increased (P<0·05) through enhancement of the expressions of GLUT4 and GLUT1 (P<0·05). The effect of isoleucine was greater than that of leucine on glucose uptake (P<0·05). Compared with newborn piglets, 35-d-old piglets have comparatively higher GLUT4, GLUT2 and GLUT5 expressions. The results of this study demonstrated that isoleucine supplementation enhanced the intestinal and muscular GLUT expressions, which have important implications that suggest that isoleucine could potentially increase muscle growth and intestinal development by enhancing local glucose uptake in animals and human beings.

The Signal Pathway of Antibiotic Alternatives on Intestinal Microbiota and Immune Function.

Antibiotics are one of the most important discoveries in the 20th century and have been widely used for treating animal diseases in the 21st century. However, antibiotic resistance among bacterial pathogens and widespread concerns regarding their use in animals has received great attention all over the world. Great attention has focused on scientific breakthroughs of the alternatives to antibiotics. Various materials such as enzymes, prebiotics, probiotics, minerals, antimicrobial peptides, acidifiers, plants and plant extracts have been tested as possible antibiotics alternatives. Owing to their effects on intestinal microbiota and immune function, research efforts have been conducted on the application of these feed supplements. This review highlights promising research results about the alternatives to antibiotics in animal husbandry that are expected to beneficially limit the adverse effects of antibiotics and ensure the safety of animal-derived foods and the environment.

Effects of dietary leucine supplementation in low crude protein diets on performance, nitrogen balance, whole-body protein turnover, carcass characteristics and meat quality of finishing pigs.

Eighteen Duroc × Landrace × Yorkshire barrows, with an average initial body weight (BW) of 75.4 ± 2.0 kg, were randomly allotted to one of three diets with six replicates per treatment for 25 days. The diets comprised a normal protein diet (NP, 14.5% crude protein), a low crude protein diet supplemented with 0.27% alanine (LP + Ala, 10.0% crude protein), or a low crude protein diet supplemented with 0.40% leucine (LP + Leu, 10.0% crude protein). The whole-body protein synthesis rate, whole-body protein breakdown rate and protein deposition rate in pigs fed the LP + Leu diet were similar to the NP diet (P > 0.05), and both were significantly higher than pigs fed the LP + Ala diet (P < 0.05). The Longissimus muscle area (LMA) of pigs fed the LP + Leu diet was larger than those fed the LP + Ala diet (P = 0.05). In addition, drip loss and intramuscular fat of pigs fed the LP + Ala diet were higher than that of the others (P < 0.05). In conclusion, supplementation of leucine in low protein diet could stimulate protein deposition and improve the meat quality of finishing pigs more than an alanine-supplemented one.

Estimation of the optimum standardized ileal digestible total sulfur amino acid to lysine ratio in late finishing gilts fed low protein diets supplemented with crystalline amino acids.

A total of 90 gilts were used to investigate the effects of various standard ileal digestible (SID) total sulfur amino acid (TSAA) to lysine (Lys) ratios on the performance and carcass characteristics of late finishing gilts receiving low crude protein (CP) diets supplemented with crystalline amino acids (CAA). Graded levels of crystalline methionine (Met) (0, 0.3, 0.5, 0.8 or 1.1 g/kg) were added to the basal diet to produce diets providing SID TSAA to Lys ratios of 0.48, 0.53, 0.58, 0.63 or 0.68. At the termination of the experiment, 30 gilts (one pig per pen) with an average body weight (BW) of 120 kg were killed to evaluate carcass traits. Increasing the SID TSAA to Lys ratio increased average daily gain (ADG) (linear and quadratic effect, P < 0.05), improved feed conversion ratio (FCR) (linear and quadratic effect, P < 0.05) and decreased serum urea nitrogen (SUN) concentration (linear and quadratic effect, P < 0.05) of finishing gilts. No effects were obtained for carcass traits. The optimum SID TSAA to Lys ratios to maximize ADG as well as to minimize FCR and SUN levels were 0.57, 0.58 and 0.53 using a linear-break point model and 0.64, 0.62 and 0.61 using a quadratic model.

Maternal N-Carbamylglutamate Supplementation during Early Pregnancy Enhances Embryonic Survival and Development through Modulation of the Endometrial Proteome in Gilts.

BACKGROUND: Early pregnancy loss is a major concern in humans and animals. N-carbamylglutamate (NCG) has been found to enhance embryonic survival during early pregnancy in rats. However, little is known about the key factors in the endometrium involved in the improvement of embryonic implantation and development induced by maternal NCG supplementation. OBJECTIVES: Our objectives were to investigate whether NCG supplementation during early gestation enhanced embryonic survival and development in gilts and to uncover the related factors using the approach of endometrium proteome analysis with isobaric tags for relative and absolute quantification (iTRAQ). METHODS: Uteruses and embryos/fetuses were obtained on days 14 and 28 of gestation from gilts fed a basal diet that was or was not supplemented with 0.05% NCG. The iTRAQ-based quantitative proteomics approach was performed to explore the endometrium proteome altered by NCG supplementation. RESULTS: Maternal NCG supplementation significantly increased the number of total fetuses and live fetuses on day 28 of gestation by 1.32 and 1.29, respectively (P < 0.05), with a significant decrease in embryonic mortality (P < 0.05). iTRAQ results indicated that a total of 59 proteins showed at least 2-fold differences (P < 0.05), including 52 proteins that were present at higher abundance and 7 proteins present at lower abundance in NCG-supplemented gilts. The differentially expressed proteins primarily are involved in cell adhesion, energy metabolism, lipid metabolism, protein metabolism, antioxidative stress, and immune response. On day 14 of gestation, several proteins closely related to embryonic implantation and development, such as integrin-αv, integrin-ß3, talin, and endothelial nitric oxide synthase, were upregulated (3.7-, 4.1-, 2.4-, and 5.4-fold increases, respectively) by NCG supplementation. CONCLUSION: To our knowledge, our results provide the first evidence that altered abundance of the endometrial proteome induced by NCG supplementation is highly associated with the improvement of embryonic survival and development in gilts.

The bacteriocin sublancin attenuates intestinal injury in young mice infected with Staphylococcus aureus.

Sublancin, a bacteriocin, has bactericidal activity against a broad spectrum of gram-positive bacteria. However, studies have not been conducted to determine its in vivo efficacy against potential pathogens. The objective of this study was to investigate the effects of sublancin in a Staphylococcus aureus (S. aureus) infected mouse model which induced intestinal injury. A total of 160, 4-week-old mice were randomly assigned to one of eight treatments. Mice in the control group were injected intraperitoneally with 0.5 mL of 0.9% saline. Mice in the other seven groups were given an intraperitoneal injection of 0.5 mL saline containing 1.0 × 10(10) colony-forming units (CFU)/mL S. aureus. Six hours after inoculation, mice in the control group were again injected with 0.5 mL of 0.9% saline. Mice in the other seven groups were injected intraperitoneally with 0.5 mL of 0.9% saline containing 0, 0.5, 1.0, 2.0, or 4.0 mg/kg body weight (BW) sublancin or 1.0 or 2.0 mg/kg BW ampicillin. The results showed that 4.0 mg/kg sublancin and 2.0 mg/kg ampicillin significantly reduced mice mortality from 55 to 10%. The height and the number of proliferated cells from the intestinal villi in the sublancin and ampicillin treated mice were higher than in the control. We conclude that sublancin has potent antibacterial activity against S. aureus. Therefore, sublancin could find use as an alternative antimicrobial agent for the treatment of gram-positive bacterial infections.

Amino acids modulates the intestinal proteome associated with immune and stress response in weaning pig.

The objective of this study was to investigate the effects of free amino acids supplementation to protein restricted diet on the intestinal morphology and proteome composition in weaning pigs. Weanling piglets were randomly fed one of the three diets including a corn-soybean based control diet and two lower protein diets with or without free amino acids supplementation for 2 weeks. The jejunum samples of piglets were collected for morphology and proteome analysis. Compared with the control diet, the protein restricted diet had a significant lower average daily gain and higher feed conversion rate. Free amino acids supplementation to the protein restricted diet significantly improved average daily gain and higher feed conversion rate, compared with the protein restricted diet. The villous height in pigs fed the protein restricted diet was lower than that of the control and free amino acids diet. Using two-dimensional gel electrophoresis and mass spectrometry, we identified 16 differentially expressed protein spots in the jejunum of the weaning piglet. These proteins were related to stress and immune response, the metabolism of carbohydrates and lipids, and tissue structure. Based on the proteome and ELISA analysis, free amino acids diet significantly down-regulated the jejunal expression of stress protein heat shock 60 kDa protein. Our results indicated that amino acids supplementation to the protein restricted diet could enhance weight gain and feed efficiency in weanling pigs through improving intestinal nutrient absorption and transportation, gut health, and mucosal immunity.

Supplementation with branched-chain amino acids to a low-protein diet regulates intestinal expression of amino acid and peptide transporters in weanling pigs.

This study determined the effects of dietary branched-chain amino acids (AA) (BCAA) on growth performance, expression of jejunal AA and peptide transporters, and the colonic microflora of weanling piglets fed a low-protein (LP) diet. One hundred and eight Large White × Landrace × Duroc piglets (weaned at 28 days of age) were fed a normal protein diet (NP, 20.9 % crude protein), an LP diet (LP, 17.1 % crude protein), or an LP diet supplemented with BCAA (LP + BCAA, 17.9 % crude protein) for 14 days. Dietary protein restriction reduced piglet growth performance and small-intestinal villous height, which were restored by BCAA supplementation to the LP diet to values for the NP diet. Serum concentrations of BCAA were reduced in piglets fed the LP diet while those in piglets fed the LP + BCAA diet were similar to values for the NP group. mRNA levels for Na(+)-neutral AA exchanger-2, cationic AA transporter-1, b(0,+) AA transporter, and 4F2 heavy chain were more abundant in piglets fed the LP + BCAA diet than the LP diet. However, mRNA and protein levels for peptide transporter-1 were lower in piglets fed the LP + BCAA diet as compared to the LP diet. The colonic microflora did not differ among the three groups of pigs. In conclusion, growth performance, intestinal development, and intestinal expression of AA transporters in weanling piglets are enhanced by BCAA supplementation to LP diets. Our findings provide a new molecular basis for further understanding of BCAA as functional AA in animal nutrition.

Dietary N-Carbamylglutamate Supplementation Boosts Intestinal Mucosal Immunity in Escherichia coli Challenged Piglets.

N-carbamylglutamate (NCG) has been shown to enhance performance in neonatal piglets. However, few studies have demonstrated the effect of NCG on the intestinal mucosal barrier. This study was conducted to determine the effects of dietary NCG supplementation on intestinal mucosal immunity in neonatal piglets after an Escherichia coli (E. coli) challenge. New-born piglets (4 d old) were assigned randomly to one of four treatments (n = 7), including (I) sham challenge, (II) sham challenge +50 mg/kg NCG, (III) E. coli challenge, and (IV) E. coli challenge +50 mg/kg NCG. On d 8, pigs in the E. coli challenge groups (III and IV) were orally challenged with 5 mL of E. coli K88 (10(8) CFU/mL), whereas pigs in the sham challenge groups (I and II) were orally dosed with an equal volume of water. On d 13, all piglets were sacrificed, and samples were collected and examined. The results show that average daily gain in the E. coli challenged piglets (III and IV) was decreased (PE.coli<0.05). However, it tended to be higher in the NCG treated piglets (II and IV). Ileum secretory IgA, as well as IFN-γ, IL-2, IL-4 and IL-10 in ileal homogenates, were increased in E. coli challenged piglets (III and IV). Similarly, ileum SIgA and IL-10 levels, and CD4(+) percentage in NCG treated piglets (II and IV) were higher than no-NCG treated piglets (PNCG<0.05). However, the IL-2 level was only decreased in the piglets of E. coli challenge + NCG group (IV) compared with E. coli challenge group (III) (P<0.05). No change in the IL-2 level of the sham challenged piglets (III) was observed. In conclusion, dietary NCG supplementation has some beneficial effects on intestinal mucosal immunity in E. coli challenged piglets, which might be associated with stimulated lymphocyte proliferation and cytokine synthesis. Our findings have an important implication that NCG may be used to reduce diarrhea in neonatal piglets.