Dietary supplementation with l-arginine partially counteracts serum metabonome induced by weaning stress in piglets

Arginine plays an important role in preventing intestinal dysfunction and metabolic disorders caused by early weaning stress. However, little is known about how arginine mitigates early weaning stress. This study was conducted to evaluate the effects of weaning stress and dietary arginine supplementation on the metabonome in the serum of piglets using (1)H NMR spectroscopy in conjunction with multivariate data analysis. Thirty castrated male piglets aged 21 d were evenly divided into three groups and fed in three different regimes: sow-fed (SF), weaned with l-alanine supplementation (ALA), and weaned with arginine supplementation (ARG). We found that early weaning stress led to a significantly reduced bodyweight gain (15.6%) and that supplementation with arginine can improve growth rates in piglets by 5.6% (P < 0.05). The early weaning stress was associated with marked alterations in lipid and amino acid metabolisms and perturbations in population and/or activities of gut microorganisms, which were manifested in increased levels of organic acids, amino acids, and acetyl-glycoproteins and reduced levels of choline metabolism and lipoproteins. Dietary supplementation with arginine could partially counteract the changes of metabolites induced by weaning stress, such as lipid and amino acid metabolisms. However, arginine was not able to restore disturbed gut microbiota. These results demonstrate the central role of arginine supplementation in regulating the metabolisms of weaned piglets.     

Increasing weaning age of piglets from 4 to 7 weeks reduces stress, increases post-weaning feed intake but does not improve intestinal functionality

This study tested the hypothesis that late weaning and the availability of creep feed during the suckling period compared with early weaning, improves feed intake, decreases stress and improves the integrity of the intestinal tract. In this study with 160 piglets of 16 litters, late weaning at 7 weeks of age was compared with early weaning at 4 weeks, with or without creep feeding during the suckling period, on post-weaning feed intake, plasma cortisol (as an indicator of stress) and plasma intestinal fatty acid binding protein (I-FABP; a marker for mild intestinal injury) concentrations, intestinal morphology, intestinal (macro)molecular permeability and intestinal fluid absorption as indicators of small intestinal integrity. Post-weaning feed intake was similar in piglets weaned at 4 weeks and offered creep feed or not, but higher (P < 0.001) in piglets weaned at 7 weeks with a higher (P < 0.05) intake for piglets offered creep feed compared with piglets from whom creep feed was witheld. Plasma cortisol response at the day of weaning was lower in piglets weaned at 7 weeks compared with piglets weaned at 4 weeks, and creep feed did not affect cortisol concentration. Plasma I-FABP concentration was not affected by the age of weaning and creep feeding. Intestinal (macro)molecular permeability was not affected by the age of weaning and creep feeding. Both in uninfected and enterotoxigenic Escherichia coli-infected small intestinal segments net fluid absorption was not affected by the age of weaning or creep feeding. Creep feeding, but not the age of weaning, resulted in higher villi and increased crypt depth. In conclusion, weaning at 7 weeks of age in combination with creep feeding improves post-weaning feed intake and reduces weaning stress but does not improve functional characteristics of the small intestinal mucosa.     

Impact of bioactive substances on the gastrointestinal tract and performance of weaned piglets: a review

The EU ban on in-feed antibiotics has stimulated research on weaning diets as a way of reducing post-weaning gut disorders and growth check in pigs. Many bioactive components have been investigated but only few have shown to be effective. Amongst these, organic acids (OA) have been shown to exert a bactericidal action mediated by non-dissociated OA, by lowering gastric pH, increasing gut and pancreas enzyme secretion and improving gut wall morphology. It has been postulated that they may also enhance non-specific immune responses and improve disease resistance. In contrast, relatively little attention has been paid to the impact of OA on the stomach but recent data show they can differently affect gastric histology, acid secretion and gastric emptying. Butyrate and precursors of butyric acid have received special attention and although promising results have been obtained, their effects are dependent upon the dose, treatment duration, initial age of piglets, gastrointestinal site and other factors. The amino acids (AA) like glutamine, tryptophan and arginine are supportive in improving digestion, absorption and retention of nutrients by affecting tissue anabolism, stress and (or) immunity. Glutamine, cysteine and threonine are important for maintaining mucin and permeability of intestinal barrier function. Spray-dried plasma (SDP) positively affects gut morphology, inflammation and reduces acquired specific immune responses via specific and a-specific influences of immunoglobulins and other bioactive components. Effects are more pronounced in early-weaned piglets and under poorer health conditions. Little interaction between plasma protein and antibiotics has been found, suggesting distinct modes of action and additive effects. Bovine colostrum may act more or less similarly to SDP. The composition of essential oils is highly variable, depending on environmental and climatic conditions and distillation methods. These oils differ widely in their antimicrobial activity in vitro and some components of weaning diets may decrease their activity. Results in young pigs are highly variable depending upon the product and doses used. These studies suggest that relatively high concentrations of essential oils are needed for beneficial effects to be observed and it has been assumed that these plant extracts mimic most of the effects of antibiotics active on gut physiology, microbiology and immunology. Often, bioactive substances protective to the gut also stimulate feed intake and growth performance. New insights on the effects of selected OA and AA, protein sources (especially SDP, bovine colostrum) and plant extracts with anti-bacterial activities on the gut are reported in this review.     

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.     

Gut-trophic feed additives and their effects upon the gut structure and intestinal metabolism. State of the art in the pig, and perspectives towards humans

The correct functional development of the gastrointestinal tract is of special importance during the neonatal and weaning phases of reared piglets. Nutrition is obviously a critical determinant in the growth of the gut in the young swine. The mucosal epithelium of the small intestine is reputed anatomically and functionally immature in neonatal pigs, a feature that appears to be exacerbated at weaning, when a colonization of the gut occurs by "new" microorganisms entering the alimentary canal with the solid feed. This frequently exposes piglets to diarrhoeic syndromes and other intestinal disturbances. Functional feed additives, also called nutraceuticals, appear as promising alternative substances to the use of chemotherapeutics as growth promoters in the rearing farm, above all considering the near banning of them by the European Parliament in the view of reducing antibiotic resistance phenomena in human therapies. Several feed additives are available that may play a role in the pig nutritional plan because of their trophic and cyto-protective effects on the gastrointestinal apparatus. Paying special attention to the quantitative consequences (histometry) upon the gut of the examined dietary supplements, this review, even if not fully exhaustive, will focus on the function (and possibly the mechanism/s of action) of certain gut-trophic nutrient substrates. This in turn will sustain the potential use of these substances in human therapy, especially the one directed at resolving intestinal diseases, both in adult and infant ages. In nutritional studies as well as in other biomedical research fields, the swine is an excellent animal model.     

Effect of dietary soy oil,glucose, and glutamine on growth performance,amino acid profile,blood profile,immunity, and antioxidant capacity in weaned piglets

Weaning stress results in gastrointestinal dysfunction and depressed performance in pigs. This study aimed to investigate the effect of soy oil, glucose, and glutamine on the growth and health of weaned piglets. Compared with those in the glutamine group, piglets in the glucose and soy oil groups had greater average daily gain, average daily feed intake, and gain: feed ratio from day 0 to 14, and gain: feed ratio for the overall period. There were no differences with regard to serum amino acids among the three groups on day 14, except glycine and threonine. The serum concentration of histidine, serine, threonine, proline, and cysteine was the highest in the glutamine group, while the content of glycine and lysine in the soy oil group on day 28 was the highest among all groups. Piglets fed with glutamine had greater serum glucose and creatinine on day 14, high-density lipoprotein on day 28, and serum IgG and IgM on day 28. Piglets in the glutamine group demonstrated lower serum total superoxide dismutase on day 14 and 28; however, they demonstrated higher total superoxide dismutase and total antioxidant capacity in the duodenum and ileum on day 14. Weaned pigs supplemented with glucose or soy oil demonstrate better growth performance possibly due to their enhanced feed intake, whereas those supplemented with glutamine may have improved immunity and intestinal oxidative capacity.     

L-Glutamate Supplementation Improves Small Intestinal Architecture and Enhances the Expressions of Jejunal Mucosa Amino Acid Receptors and Transporters in Weaning Piglets

L-Glutamate is a major oxidative fuel for the small intestine. However, few studies have demonstrated the effect of L-glutamate on the intestinal architecture and signaling of amino acids in the small intestine. The aim of this study was to investigate the effects of dietary L-glutamate supplementation on the intestinal architecture and expressions of jejunal mucosa amino acid receptors and transporters in weaning piglets. A total of 120 weaning piglets aged 35±1 days with an average body weight at 8.91±0.45 kg were randomly allocated to two treatments with six replicates of ten piglets each, fed with diets containing 1.21% alanine, or 2% L-glutamate. L-Glutamate supplementation increased the activity of glutamate oxaloacetate transaminase (GOT) in the jejunal mucosa. Also, the mRNA expression level of jejunal mucosa glutamine synthetase (GS) was increased by L-glutamate supplementation. The height of villi in duodenal and jejunal segments, and the relative mRNA expression of occludin and zonula occludens protein-1 (ZO-1) in jejunal mucosa were increased by dietary L-glutamate supplementation. L-Glutamate supplementation increased plasma concentrations of glutamate, arginine, histidine, isoleucine, leucine, methionine, phenylalanine and threonine. L-Glutamate supplementation also increased the relative mRNA expression of the jejunal mucosa Ca²⁺-sensing receptor (CaR), metabotropic glutamate receptor 1 (mGluR1) and metabotropic glutamate receptor 4 (mGluR4), and neutral amino acid transporter B⁰-like (SLC1A5) in the jejunal mucosa. These findings suggest that dietary addition of 2% L-glutamate improves the intestinal integrity and influences the expression of amino acid receptors and transporters in the jejunum of weaning, which is beneficial for the improvement of jejunal nutrients for digestion and absorption.     

Effects of oral supplementation with Spirulina and Chlorella on growth and digestive health in piglets around weaning

Weaning of piglets is associated with important changes in gut structure and function resulting from stressful events such as separation from the sow, moving to a new facility and dietary transition from a liquid to a solid feed. This may result in post-weaning diarrhoea and a decrease in feed intake and growth. In humans, the cyanobacterium Spirulina platensis (SP) and the freshwater microalga Chlorella vulgaris (CV) are known for their beneficial health effects. This study aimed to determine the effects of early oral administration of Spirulina and Chlorella in piglets on mucosal architecture and cytokine expression in the intestine around weaning, and consequences on growth performance and diarrhoea incidence. The experiment was conducted on 108 suckling piglets of 14 days of age (initial BW=4.9±0.7 kg) and weaned at 28 days of age (day 0). Animals received orally 385 mg/kg BW per day of SP or CV, or water (negative control (NC)) during 4 weeks from day −14 to day 14 and their growth performance was measured daily. After weaning, growth, feed intake and diarrhoea incidence were measured daily. Intestinal morphology and functionality were assessed at day −1, day 2, and day 14. During the suckling period, average daily gain (ADG) in SP piglets was higher, resulting in a higher weaning BW compared to NC and CV piglets (P<0.05). No significant difference between treatments was observed for ADG, average daily feed intake, and gain to feed (G : F) ratio after weaning, but the extent of growth retardation after weaning was the lowest in piglets supplemented with Chlorella (P<0.01). Supplementation with Spirulina reduced diarrhoea incidence by 50% from day 0 to day 14 (P<0.05). Mucosal architecture at the jejunum was unaffected by Spirulina or Chlorella administration (P>0.10). Shorter ileal villi were measured in SP and CV piglets than in NC piglets (P<0.05). Cytokine expression did not differ between treatments in response to weaning. At day 14, IL-8 expression in the ileum was higher in SP piglets, while IL-1β expression in the jejunum was higher in CV piglets (P<0.05). This study shows that Spirulina administration around weaning alleviates diarrhoea in weaned piglets, without marked modulation of local inflammation.     

Effects of weaning age and formic acid-based feed additives on pigs from weaning to slaughter

Two hundred and forty piglets were used in a 2 x 6 factorial experiment to study the effects of weaning age (26 or 36 d) and four formic acid-based feed additives on the performance of pigs from weaning to slaughter. Either formic acid (F) or a mixture of formic acid, propionic acid, and potassium sorbate (FPS) or a mixture of formic acid, propionic acid, and sodium benzoate (FPB) or formic acid in a diatomaceous earth carrier (FD) were added to the diets of weaned piglets (from weaning to 60 d of age) and growing (18-46 kg) and finishing pigs (46-107 kg) to provide 8, 6, and 6 g acid per kg feed, respectively. The negative control treatment's (C) diets contained no growth promoters, whereas the positive control treatment's weaner and grower diets were supplemented with 40 mg/kg of avilamycin (A). The piglets weaned at the age of 26 and 36 d weighed 7.6 and 10.7 kg at weaning (p < 0.001), and 18.5 and 17.9 kg at the age of 60 d (p > 0.05), respectively. There was a weaning age x feed additive interaction in the weight gain of piglets after weaning (p < 0.05). The weight gain of piglets weaned on day 26 was enhanced by A, FPS, and FD (p < 0.05), and that of piglets weaned on day 36 by A and FPB (p < 0.05). The feed conversion ratio was not affected by weaning ages but was decreased in groups A, F, FBS, and FPB (p < 0.05). The severity of post-weaning diarrhoea was less in groups A, F, FPS, and FD than in C (p < 0.05). In piglets weaned on day 26, faecal water content and the total Escherichia coli count were highest 9 d after weaning. The total E. coli count was reduced only by FD (p < 0.05). Increased faecal water content was characterized by increased faecal Na+ and decreased K+ concentrations. Weaning age did not influence performance or carcass quality in the growing-finishing pigs. Feed additives did not affect weight gain in the growing pigs, but FPS and FPB enhanced weight gain during finishing period and total fattening (p < 0.05). In summary, the pigs' growth performance from weaning to slaughter was not affected by weaning age but it was enhanced by mixtures of formic and propionic acids with small amounts of sorbate or benzoate.     

Effects of glutamine supplementation on the immune status in weaning piglets with intrauterine growth retardation

Neonates with intrauterine growth retardation (IUGR) often suffer from impaired cellular immunity, and weaning may further aggravate adverse effects of IUGR on development and function of the immune system. In this study, we investigated effects of glutamine supplementation on immune status in the intestines of weaning pigs with IUGR, focusing on molecular mechanisms underlying altered immune response. Piglets with IUGR were weaned at 21 days of age and received orally 1.22 g alanine or 1 g glutamine per kg body weight every 12?h. Weight gain and intestinal weight of weaning piglets were increased by glutamine supplementation. Levels of serum IgG in piglets supplemented with glutamine were increased compared with Control piglets. The production of IL-1 and IL-8 in the serum and jejunum was decreased by glutamine supplementation, whereas the levels of IL-4 in the serum and the concentrations of IL-4 and IL-10 in the jejunum were increased. The expression of heat shock protein 70 (Hsp70) in the jejunum was increased by glutamine supplementation, but the degradation of inhibitor?κB and the activity of nuclear factor-κB (NF-κB) were decreased. In conclusion, glutamine supplementation enhanced immune response in weaning piglets with IUGR. The effects of glutamine in IUGR are associated with increased Hsp70 expression and suppression of NF-κB activation.     

Effects of feeding antibiotic-free creep feed supplemented with oligofructose, probiotics or synbiotics to suckling piglets increases the preweaning weight gain and composition of intestinal microbiota

The objective of this study was to determine whether feeding an antibiotic-free creep feed supplemented with either oligofructose, probiotics or synbiotics to suckling piglets influences growth performance, the gut microflora, gut morphology and hematological traits at weaning. Twenty sows with 10 piglets each were randomly assigned to one of four treatments. The treatments consisted of a control (antibiotic-free) diet, 0.2% oligofructose (OF), 0.3% probiotics or 0.5% synbiotics (mixture of 0.2% OF+0.3% probiotics). Piglets were offered the diet ad libitum from 7 d after birth until one day after weaning (21 d of age). At the day after weaning, blood samples were collected from the jugular vein to determine the immune response. Digesta samples of the ileum and colon were collected to determine the microbial composition. Tissue segments from the duodenum and ileum were collected for morphometric measurements of the small intestine. The average daily weight gain was significantly higher for piglets fed the OF or synbiotics diet compared with the pigs fed the control diet. The hematological traits (the concentration of lymphocytes and neutrophils in whole blood) were not affected by the diet. Piglets fed the OF, probiotics or synbiotics diet had a significantly decreased number of total coliform bacteria in the colon. Feeding OF, probiotics or synbiotics significantly increased the population of bifidobacteria in the ileum compared to the control. In the colon, the probiotics and synbiotics diet significantly increased the number of bifidobacteria compared with the control diet. The results of this experiment showed that supplementation of oligofructose or synbiotics to an antibiotic-free creep feed during the preweaning period affected gut microbial population and performance of piglets.     

Proteomic analysis reveals altered expression of proteins related to glutathione metabolism and apoptosis in the small intestine of zinc oxide-supplemented piglets

Zinc is an important dietary factor that regulates intestinal amino acid and protein metabolism in animals. Recent work with the piglet, an established animal model for studying human infant nutrition, has shown that supplementing high levels of zinc oxide (ZnO) to the diet ameliorates weaning-associated intestinal injury and growth retardation. However, the underlying mechanisms are largely unknown. This study tested the hypothesis that zinc supplementation affects expression of proteins related to glutathione metabolism and oxidative stress in the gut. Using two-dimensional gel electrophoresis and mass spectrometry, we identified 22 up-regulated and 19 down-regulated protein spots in the jejunum of weanling piglets supplemented with ZnO (3,000 mg/kg Zn) compared with the control pigs (100 mg/kg Zn). These proteins are related to energy metabolism (increased level for succinyl-CoA transferase and decreased level for creatine kinase M-type); oxidative stress (decreased levels for 78 kDa glucose-regulated protein and glutathione-S-transferase-ω); and cell proliferation and apoptosis (increased levels for A-Raf-1 and calregulin). Consistent with the changes in protein expression, the ratio of reduced glutathione to oxidized glutathione was increased, whereas glutathione-S-transferase and glutathione peroxidase activities as well as the protein level of active caspase-3 were reduced in ZnO-supplemented piglets. Collectively, these results indicate that ZnO supplementation improves the redox state and prevents apoptosis in the jejunum of weaning piglets, thereby alleviating weaning-associated intestinal dysfunction and malabsorption of nutrients (including amino acids).     

Effects of pre-weaning housing in a multi-suckling system on performance and carbohydrate absorption of relatively light and heavy piglets around weaning

The low feed intake and stress associated with abrupt weaning in conventional pig farming often result in poor post-weaning performance, which is related to impaired intestinal function. We investigated effects of housing conditions before weaning on performance around weaning of relatively light and heavy piglets. Before weaning, piglets were housed either with five sows and their litters in a multi-suckling (MS) system or in pens with individually housed sows in farrowing crates (FC). After weaning at 4 weeks of age (day 0), 16 groups of four piglets (two light and two heavy litter-mates) were housed under equal conditions in enriched pens. Mannitol (day −5 and day 5) and galactose (day 5) were orally administered as markers for gastrointestinal carbohydrate absorption, and after 20 min a blood sample was taken (sugar absorption test). In addition, BW, feed intake and faecal consistency as an indicator for diarrhoea, were assessed frequently during 2 weeks post-weaning. Pre-weaning housing, weight class and their interaction did not affect post-weaning faecal consistency scores. Weight gain over 2 weeks did not differ between pre-weaning housing treatments, but MS piglets gained more (0.67±0.12 kg) than FC piglets (0.39±0.16 kg) between days 2 and 5 post-weaning, P=0.02), particularly in the ‘heavy’ weight class (interaction, P=0.04), whereas feed intake was similar for both treatments. This indicates a better utilisation of the ingested feed of the MS piglets compared with the FC piglets in the early post-weaning period. Pre-weaning mannitol concentrations were unaffected by pre-weaning housing, weight class and their interaction. On day 5 post-weaning, however, MS piglets had a lower plasma concentration of mannitol (320 v. 592 nmol/ml, SEM=132, P=0.04) and galactose (91 v. 157 nmol/ml, SEM=20, P=0.04) than FC piglets, regardless of weight class. In conclusion, MS and FC piglets differed in aspects of post-weaning gastrointestinal carbohydrate absorption and in weight gain between days 2 and 5 after weaning, but pre-weaning housing did not affect feed intake, weight gain and measures of faecal consistency over the first 2 weeks after weaning.     

Importance of sanitary environment for growth performance and plasma nutrient homeostasis during the post-weaning period in piglets

Deterioration of sanitary conditions in piggeries is known to limit growth performance through inducing a moderate immune response. This article reports the results of an experiment performed to reproduce the consequences of bad sanitary conditions on growth performance and nutrient plasma concentrations of piglets after weaning. We propose to use these experimental conditions as a model for studying the interactions between nutrition and pig health. In this experiment, 20 pairs of littermate piglets were selected and weaned at 28 days of age on the basis of their body weight. Within each pair, piglets were pair-fed and each one was affected to one of the two experimental groups. The first group was housed in a clean environment and was fed an antibiotic supplemented standard diet. The second group was kept in unsanitary rooms, mixed with non-experimental piglets and was fed the same standard diet but without antibiotic supplementation. Compared to pigs kept in the clean environment, piglets kept in the unsanitary environment had significantly lower rate of weight gain and feed efficiency from weaning to 20 d post weaning then from 36 - 45 d post weaning. They also displayed higher plasma concentrations of haptoglobin, copper, vitamin B12 and lysine but lower concentrations of glutathione, pyridoxal-5-phosphate, folic acid, threonine and tryptophan. Our results showed that a reduction of growth performance and a modification of nutrient utilization can be induced by decreasing the sanitary quality of environment where pigs are kept after weaning and after transition to another building. This response could be explained by a moderated activation of body defences.     

Dietary supplementation of weaned piglets with a yeast-derived mannan-rich fraction modulates cecal microbial profiles,jejunal morphology and gene expression

The development of nutritional strategies to improve microbial homeostasis and gut health of piglets post-weaning is required to mitigate the high prevalence of post-weaning diarrhea and subsequent growth checks typically observed during the weaning transition. Therefore the objective of this study was to determine the effect of supplementing piglet creep and nursery feed with a yeast-derived mannan-rich fraction (MRF) on piglet growth performance, cecal microbial profiles, and jejunal morphology and gene expression. Ten litters of piglets (n=106) were selected on postnatal day (PND) 7 and assigned to diets with or without MRF (800 mg/kg) until weaning (n=5 litters/treatment; initial weight 3.0±0.1 kg). On PND 21, 4 piglets per litter (n=40) were selected and weaned into the nursery where they remained on their respective diets until PND 42. A two-phase feeding program was used to meet nutrient requirements, and pigs were switched from phase 1 to phase 2 on PND 28. Feed intake and piglet weights were recorded on PND 7, 14, 21, 28, 35 and 42. On PND 28 and 42, ten piglets per treatment were euthanized to collect intestinal tissue and digesta. Piglets supplemented with MRF had 21.5% greater (P<0.05) average daily feed intake between PND 14-21. However, MRF supplementation did not affect piglet growth performance compared to control. On PND 28, jejunal villus height was 16.8% greater (P<0.05) in piglets consuming MRF supplemented diets. Overall microbial community structure in cecal digesta on PND 28 tended to differ in pigs supplemented with MRF (P=0.076; analysis of similarities (ANOSIM)) with increased (P<0.05) relative abundance of Paraprevotellaceae genera YRC22 and CF231, and reduced (P<0.05) relative abundance of Sutterella and Prevotella. Campylobacter also tended to reduce (P<0.10) in MRF supplemented piglets. On PND 28 differential gene expression in jejunal tissue signified an overall effect of supplementing MRF to piglets. Downstream analysis of gene expression data revealed piglets supplemented with MRF had enriched biological pathways involved in intestinal development, function and immunity, supporting the observed improvement in jejunal villus architecture on PND 28. On PND 42 there was no effect of MRF supplementation on jejunal morphology or overall cecal microbial community structure. In conclusion, supplementing Actigen™, a MRF, to piglets altered cecal microbial community structure and improved jejunal morphology early post-weaning on PND 28, which is supported by enrichment of intestinal development pathways.     

Non-essential amino acid sources in crystalline amino acid diets for trout (Oncorhynchus mykiss)

A study was conducted over a 84-day period to evaluate glycine, L-glutamic acid and L-glutamine as sources of non-essential amino acids (NEAA) in dietary 'protein' consisting of crystalline amino acids only. The study was performed with a total of 1200 rainbow trout fingerlings ( Oncorhynchus mykiss ) of 48 g mean body mass. The addition of non-essential amino acids (NEAA) to essential amino acids (EAA) evidently improved growth and feed efficiency: glutamine was superior to glycine and glycine superior to glutamic acid. However, the best results in growth were obtained by adding a mixture of all three NEAA. The improvement of trout performance by glutamine may hypothetically be traced back to a better amino acid absorption capacity by a less acidic intestinal milieu. In consequence, the optimal EAA to NEAA ratio may have to be redefined.     

Effects of Weaning on Intestinal Upper Villus Epithelial Cells of Piglets

The intestinal upper villus epithelial cells represent the differentiated epithelial cells and play key role in digesting and absorbing lumenal nutrients. Weaning stress commonly results in a decrease in villus height and intestinal dysfunction in piglets. However, no study have been conducted to test the effects of weaning on the physiology and functions of upper villus epithelial cells. A total of 40 piglets from 8 litters were weaned at 14 days of age and one piglet from each litter was killed at 0 d (w0d), 1 d (w1d), 3 d (w3d), 5 d (w5d), and 7 d (w7d) after weaning, respectively. The upper villus epithelial cells in mid-jejunum were isolated using the distended intestinal sac method. The expression of proteins in upper villus epithelial cells was analyzed using the isobaric tags for relative and absolute quantification or Western blotting. The expression of proteins involved in energy metabolism, Golgi vesicle transport, protein amino acid glycosylation, secretion by cell, transmembrane transport, ion transport, nucleotide catabolic process, translational initiation, and epithelial cell differentiation and apoptosis, was mainly reduced during the post-weaning period, and these processes may be regulated by mTOR signaling pathway. These results indicated that weaning inhibited various cellular processes in jejunal upper villus epithelial cells, and provided potential new directions for exploring the effects of weaning on the functions of intestine and improving intestinal functions in weaning piglets.     

Effects of weaning age and formic acid-based feed additives on pigs from weaning to slaughter

Abstract

Two hundred and forty piglets were used in a 2×6 factorial experiment to study the effects of weaning age (26 or 36 d) and four formic acid-based feed additives on the performance of pigs from weaning to slaughter. Either formic acid (F) or a mixture of formic acid, propionic acid, and potassium sorbate (FPS) or a mixture of formic acid, propionic acid, and sodium benzoate (FPB) or formic acid in a diatomaceous earth carrier (FD) were added to the diets of weaned piglets (from weaning to 60 d of age) and growing (18 – 46 kg) and finishing pigs (46 – 107 kg) to provide 8, 6, and 6 g acid per kg feed, respectively. The negative control treatment's (C) diets contained no growth promoters, whereas the positive control treatment's weaner and grower diets were supplemented with 40 mg/kg of avilamycin (A). The piglets weaned at the age of 26 and 36 d weighed 7.6 and 10.7 kg at weaning (p < 0.001), and 18.5 and 17.9 kg at the age of 60 d (p > 0.05), respectively. There was a weaning age×feed additive interaction in the weight gain of piglets after weaning (p < 0.05). The weight gain of piglets weaned on day 26 was enhanced by A, FPS, and FD (p < 0.05), and that of piglets weaned on day 36 by A and FPB (p < 0.05). The feed conversion ratio was not affected by weaning ages but was decreased in groups A, F, FBS, and FPB (p < 0.05). The severity of post-weaning diarrhoea was less in groups A, F, FPS, and FD than in C (p < 0.05). In piglets weaned on day 26, faecal water content and the total Escherichia coli count were highest 9 d after weaning. The total E. coli count was reduced only by FD (p < 0.05). Increased faecal water content was characterized by increased faecal Na⁺ and decreased K⁺ concentrations. Weaning age did not influence performance or carcass quality in the growing-finishing pigs. Feed additives did not affect weight gain in the growing pigs, but FPS and FPB enhanced weight gain during finishing period and total fattening (p < 0.05). In summary, the pigs' growth performance from weaning to slaughter was not affected by weaning age but it was enhanced by mixtures of formic and propionic acids with small amounts of sorbate or benzoate.     

Dietary alanyl-glutamine improves growth performance of weaned piglets through maintaining intestinal morphology and digestion–absorption function

Alanyl-glutamine (Ala-Gln), a highly soluble and stable glutamine dipeptide, is known to improve gut integrity and function. The aim of this study was to evaluate whether dietary Ala-Gln supplementation could improve growth performance, intestinal development and digestive-absorption function in weaned piglets. A total of 100 purebred Yorkshire piglets weaned at 21 days of age were assigned randomly to four dietary treatment groups and fed a basal diet (control group) or a basal diet containing 0.15%, 0.30% and 0.45% Ala-Gln, respectively. Compared with the control group, piglets fed the Ala-Gln diets had higher average daily gain and lower feed : gain and diarrhea rate (P < 0.05). Moreover, dietary Ala-Gln supplementation increased villous height and villous height : crypt depth ratio in duodenum and jejunum (P < 0.05), as well as the activities of maltase and lysozyme in jejunum mucosa (P < 0.05). In addition, a decrease in serum diamine oxidase activity and crypt depth in duodenum and jejunum was observed in piglets fed the Ala-Gln diets (P < 0.05). Serum cytosolic phospholipase A2 (cPLA2) concentration and gene expression of cPLA2, Na⁺-dependent glucose transporter 1, glucose transporter 2 and peptide transporter 1 in jejunum were increased by feeding Ala-Gln diets relative to control diet (P < 0.05). These results indicated that feeding Ala-Gln diet has beneficial effects on the growth performance of weaned piglets, which associated with maintaining intestinal morphology and digestive-absorption function.     

Effect of milk deprivation during the lactation period on performance and digestive enzyme activities of the piglets following weaning

Post-weaning performance of piglets from systems where lactation is disrupted (e.g. from multisuckling systems) is superior to conventionally reared piglets. The objective of this study was to establish whether restricted growth prior to weaning caused by disruption of suckling was an important factor in post-weaning performance and also whether there were related changes in gastro-intestinal development. Ten litters of eight piglets were used in a split-plot design. Half of each litter (limited suckling, LS) had suckling disrupted by separation from their dam for 7 h/day from day 14 to 28 after farrowing. The remainder of each litter was allowed to suck normally (normal suckling, NS). The same amount of creep feed was offered to LS piglets as consumed by NS littermates on the previous day. There were no differences in weight between LS and NS piglets at 14 days of age, but restricting access to the sow reduced weaning weight at 28 days of age (7.96 v. 9.00 kg; LS v. NS; P < 0.01; s.e.d. 0.23). Feed intakes were greater for LS than NS piglets over the first 28 days post weaning, particularly in the 1st week after weaning when feed efficiency was also improved (0.91 v. 0.62 kg gain per kg feed; P < 0.01; s.e.d. 0.08). As a result, LS piglets grew more rapidly in the first 28 days post weaning, particularly in the first 7 days after weaning. Subsequent performance to 8 weeks was similar for both groups. Digestive organ weights were not different at 2 and 9 days after weaning; nor were small intestine specific enzyme activities significantly different ( P>0.05). Pancreatic trypsin activity was, however, greater ( P < 0.01) for LS pigs on both days 2 and 9 post weaning. In conclusion the restriction of growth as a result of limited suckling itself is an important factor in determining post-weaning performance and may be related to development of pancreatic trypsin activity.