Effects of Copper-Loaded Chitosan Nanoparticles on Intestinal Microflora and Morphology in Weaned Piglets

The objective of the present study was to investigate the effects of dietary supplementation with copper-loaded chitosan nanoparticles (CNP-Cu) on growth performance, intestinal microflora, and morphology in weaned piglets. A number of 90 weaned piglets (Duroc × Landrace × Yorkshire), weaned at 21?days with body weight of 7.2?±?0.81?kg, were randomly divided into three groups by weight and sex, each treatment including three replicates of ten pigs. The piglets were fed the same basal diet supplemented with 0 (the control group), 100?mg/kg CNP-Cu, and 100?mg/kg chlortetracycline (the positive group). The results showed that 100?mg/kg CNP-Cu significantly increased average daily gain and feed intake and decreased feed/gain ratio and diarrhea rate (P?<?0.05). Compared with the control group, the amount of Escherichia coli in duodenum, jejunal, and caecum were significantly decreased by 100?mg/kg CNP-Cu; the number of lactobacillus in jejunal and caecum were increased (P?<?0.05), and the amount of bifidobacterium in duodenum and caecum were also increased (P?<?0.05). Moreover, the villous height of duodenum, jejunum, and ileum mucosa was significantly increased (P?<?0.05), and the crypt depth was significantly decreased (P?<?0.05). The results indicated that CNP-Cu is beneficial to growth and intestinal microflora and morphology and could be a potential substitution of chlortetracycline in diets of weaned piglets.     

Fluoride Exposure Aggravates the Testicular Damage and Sperm Quality in Diabetic Mice: Protective Role of Ginseng and Banaba

The current study was conducted to investigate the effects of dietary zinc oxide (ZnO) on the antioxidant capacity, small intestine development, and jejunal gene expression in weaned piglets. Ninety-six 21-day-old piglets were randomly assigned to three dietary treatments. Each treatment had eight replicates with four piglets per replicate. The piglets were fed either control diet (control) or control diet supplemented with in-feed antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) or pharmacological doses of ZnO (3000 mg/kg). The experiment lasted 4 weeks. Blood samples were collected at days 14 and 28, while intestinal samples were harvested at day 28 of the experiment. Dietary high doses of ZnO supplementation significantly increased the body weight (BW) at day 14 and average daily gain (ADG) of days 1 to 14 in weaned piglets, when compared to control group (P < 0.05). The incidence of diarrhea of piglets fed ZnO-supplemented diets, at either days 1 to 14, days 14 to 28, or the overall experimental period, was significantly decreased in comparison with those in other groups (P < 0.05). Supplementation with ZnO increased the villus height of the duodenum and ileum in weaned piglets and decreased the crypt depth of the duodenum, when compared to the other groups (P < 0.05). Dietary ZnO supplementation decreased the malondialdehyde (MDA) concentration at either day 14 or day 28, but increased total superoxide dismutase (T-SOD) at day 14, when compared to that in the control (P < 0.05). ZnO supplementation upregulated the messenger RNA (mRNA) expression of zonula occludens-1 (ZO-1) and occludin in the jejunum mucosa of weaned piglets, compared to those in the control (P < 0.05). The pro-inflammatory cytokine interleukin-lβ (IL-1β) mRNA expression in the jejunum mucosa was downregulated in the ZnO-supplemented group, compared with the control (P < 0.05). Both in-feed antibiotics and ZnO supplementation decreased the mRNA expression of interferon-γ (IFN-γ), but increased the mRNA expression of transforming growth factor-β (TGF-β), in the jejunum mucosa of piglets, when compared to those in the control (P < 0.05). In summary, supplemental ZnO was effective on the prevention of post-weaning diarrhea (PWD) in weaned piglets and showed comparative growth-promoting effect on in-feed antibiotics, probably by the mechanism of improvement of the antioxidant capacity, restoration of intestinal barrier function and development, and modulation of immune functions.     

Effects of Chitosan on Intestinal Inflammation in Weaned Pigs Challenged by Enterotoxigenic Escherichia coli

The aim of this study was to investigate whether supplementation with chitosan (COS) could reduce diarrhea and to explore how COS alleviates intestinal inflammation in weaned pigs. Thirty pigs (Duroc×Landrace×Yorkshire, initial BW of 5.65±0.27) weaned at age 21 d were challenged with enterotoxigenic Escherichia coli during a preliminary trial period, and then divided into three treatment groups. Pigs in individual pens were fed a corn-soybean meal diet, that contained either 0 (control), 50 mg/kg chlortetracycline, or 300 mg/kg COS for 21 days. The post-weaning diarrhea frequency, calprotectin levels and TLR4 protein expression were decreased (P<0.05) in both the COS and chlortetracycline groups compared with control. Simultaneously, supplemental COS and chlortetracycline had no effect on the mRNA expression of TNF-α in the jejunal mucosa, or on the concentrations of IL-1β, IL-6 and TNF-α in serum. However, COS supplementation improved (P<0.05) the mRNA expression of IL-1β and IL-6 in the jejunal mucosa. The results indicate that supplementation with COS at 300 mg/kg was effective for alleviating intestinal inflammation and enhancing the cell-mediated immune response. As feed additives, chitosan and chlortetracycline may influence different mechanisms for alleviating inflammation in piglets.     

酶解乳蛋白对初生仔猪小肠组织学结构及隐窝细胞增殖的影响(英文)

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｉｎｔｅｓｔｉｎｅａｓｔｈｅｍａｊｏｒｉｎｔｅｒｆａｃｅｂｅｔｗｅｅｎａｎｏｒｇａｎｉｓｍａｎｄｉｔｓｎｕｔｒｉｔｉｏｎａｌｅｎｖｉｒｏｎｍｅｎｔｐｌａｙｓａｃｒｉｔｉｃａｌｒｏｌｅｉｎｐｏｓｔｎａｔａｌｄｅｖｅｌｏｐｍ...     

Effects of the antimicrobial peptide cecropin AD on performance and intestinal health in weaned piglets challenged with Escherichia coli

This study was conducted to determine the effects of the antimicrobial peptide cecropin on performance and intestinal health in piglets. Newly weaned barrows were randomly assigned to one of three treatments (n=8), including a corn-soybean basal diet or similar diets supplemented with antibiotics (100 mg/kg kitasamycin plus 800 mg/kg colistin sulfate) or 400 mg/kg cecropin AD. On day 13, all piglets were orally challenged with 10(9)CFU/mL of Escherichia coli K88. On day 19, all piglets were euthanized and sampled. Before challenge, piglets fed antibiotics had greater weight gain, feed efficiency, nitrogen and energy retention than the control (P<0.05). E. coli challenge decreased weight gain, feed intake and feed efficiency for the control piglets (P<0.05) but not for the antibiotic or cecropin AD treated piglets. The incidence of diarrhea post-challenge in the antibiotic and cecropin AD treatments decreased compared with the control piglets. The total viable counts of cecal E. coli were lower while the Lactobacilli counts were higher in the antibiotic and cecropin AD treatments compared with the control (P<0.05). Cecropin AD treatment decreased total aerobes while increasing total anaerobes in the ileum (P<0.05). A higher villus height to crypt depth ratio in the jejunum and ileum as well as a deeper crypt depth in the jejunum and higher villus height in the ileum were observed in piglets fed antibiotics or cecropin AD compared with control piglets (P<0.05). Piglets fed the control diet had lower levels of secretory IgA in their jejunum and lower serum IgA, IgG, interleukin-1β and interleukin-6 compared with the other treatments (P<0.05). Overall, these data suggest that cecropin AD enhances pig performance through increasing immune status and nitrogen and energy retention as well as reducing intestinal pathogens in weaned piglets.     

Protective effects of N-acetylcysteine on intestinal functions of piglets challenged with lipopolysaccharide

The neonatal small intestine is susceptible to damage by endotoxin, but effective methods for prevention and treatment are lacking. N-acetylcysteine (NAC) is a widely used precursor of L: -cysteine for animal cells and plays an important role in protecting cells against oxidative stress. This study was conducted with the lipopolysaccharide (LPS)-challenged piglet model to determine the effects of NAC on intestinal function. Eighteen piglets were randomly allocated into control, LPS and LPS?+?NAC groups. The control and LPS groups were fed a corn- and soybean meal-based diet, and the LPS?+?NAC group was fed the basal diet +500?mg/kg NAC. On days 10, 13 and 20 of the trial, the LPS and LPS?+?NAC groups received intraperitoneal administration of LPS (100?μg/kg BW), whereas the control piglets received saline. On day 20 of the trial, D-: xylose (0.1?g/kg BW) was orally administrated to all piglets 2?h after LPS or saline injection, and blood samples were collected 1?h thereafter. One hour blood xylose test was used to measure intestinal absorption capacity and mucosal integrity, and diamine oxidase (DAO) was used as a marker of intestinal injury. On day 21 of the trial, pigs were killed to obtain the intestinal mucosa. Compared to the control, LPS challenge reduced (P?相似文献   

Apical Na+-D-glucose cotransporter 1 (SGLT1) activity and protein abundance are expressed along the jejunal crypt-villus axis in the neonatal pig

Gut apical Na(+)-glucose cotransporter 1 (SGLT1) activity is high at the birth and during suckling, thus contributing substantially to neonatal glucose homeostasis. We hypothesize that neonates possess high SGLT1 maximal activity by expressing apical SGLT1 protein along the intestinal crypt-villus axis via unique control mechanisms. Kinetics of SGLT1 activity in apical membrane vesicles, prepared from epithelial cells sequentially isolated along the jejunal crypt-villus axis from neonatal piglets by the distended intestinal sac method, were measured. High levels of maximal SGLT1 uptake activity were shown to exist along the jejunal crypt-villus axis in the piglets. Real-time RT-PCR analyses showed that SGLT1 mRNA abundance was lower (P < 0.05) by 30-35% in crypt cells than in villus cells. There were no significant differences in SGLT1 protein abundances on the jejunal apical membrane among upper villus, middle villus, and crypt cells, consistent with the immunohistochemical staining pattern. Higher abundances (P < 0.05) of total eukaryotic initiation factor 4E (eIF4E) protein and eIE4E-binding protein 1 γ-isoform in contrast to a lower (P < 0.05) abundance of phosphorylated (Pi) eukaryotic elongation factor 2 (eEF2) protein and the eEF2-Pi to total eEF2 abundance ratio suggest higher global protein translational efficiency in the crypt cells than in the upper villus cells. In conclusion, neonates have high intestinal apical SGLT1 uptake activity by abundantly expressing SGLT1 protein in the epithelia and on the apical membrane along the entire crypt-villus axis in association with enhanced protein translational control mechanisms in the crypt cells.     

Overall assessment of antimicrobial peptides in piglets: a set of meta-analyses

Developing alternatives to antibiotics is an urgent need in livestock production. Antimicrobial peptides (AMPs) are regarded as powerful antibiotic substitutes (ASs) because AMPs have broad-spectrum antimicrobial activities and growth-promoting ability. Here, we aimed to comprehensively assess the effects of AMPs on the growth performance, diarrhea rate, intestinal morphology and immunity of healthy or challenged piglets, compared with an antibiotics group or negative control group. We performed a set of meta-analyses of feeding trials from database inception to 27 May 2019. Among the 1379 identified studies, 20 were included in our meta-analyses (56 arms and 4067 piglets). The meta-analyses revealed that (1) compared with the negative control group, AMPs significantly improved the healthy piglets’ average daily gain (ADG), average daily feed intake (ADFI), gain : feed ratio (G/F), levels of immune globulin (Ig) IgM and IgG, and intestinal villus height : crypt depth ratio (V/C) (P < 0.05). Meanwhile, AMPs significantly increased the challenged piglets’ ADG, ADFI, G/F and V/C of the jejunum and ileum, and notably deceased the diarrhea rate (P < 0.05); (2) compared with antibiotics group, the effects of AMPs were slightly weaker than those of antibiotics in the healthy piglets, but AMPs have similar effects to those of antibiotics in challenged piglets. In a higher purity, the optimal dose of AMPs may be approximately 0.01%. Our findings indicate that AMPs can improve piglet growth performance, enhance immunity, benefit intestinal morphology and decrease the diarrheal rate. AMPs could be great ASs especially under infection conditions.     

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.     

Effects of dietary addition of heat-killed Mycobacterium phlei on growth performance,immune status and anti-oxidative capacity in early weaned piglets

The contradiction between high susceptibility of early weaned piglets to enteric pathogens and rigid restriction of antibiotic use in the diet is still prominent in the livestock production industry. To address this issue, the study was designed to replace dietary antibiotics partly or completely by an immunostimulant, namely heat-killed Mycobacterium phlei (M. phlei). Piglets (n = 192) were randomly assigned to one of the four groups: (1) basal diet (Group A), (2) basal diet + a mixture of antibiotics (80 mg/kg diet, Group B), (3) basal diet + a mixture of antibiotics (same as in Group B, but 40 mg/kg diet) + heat-killed M. phlei (1.5 g/kg diet) (Group C) and (4) basal diet + heat-killed M. phlei (3 g/kg diet) (Group D). All piglets received the respective diets from days 21 to 51 of age and were weaned at the age of 28 d. Compared with the Control (Group A), in all other groups the average daily gain, average daily feed intake, small intestinal villus height:crypt depth ratio and protein levels of occludin and ZO-1 in the jejunal mucosa were increased. A decreased incidence of diarrhoea in conjunction with an increased sIgA concentration in the intestinal mucosa and serum IL-12 and IFN-γ concentrations was found in groups supplemented with heat-killed M. phlei (Groups C and D), but not in Group B. Groups C and D also showed decreased IL-2 concentrations in the intestinal mucosa with lower TLR4 and phosphor-IκB protein levels. The antioxidant capacity was reinforced in Groups C and D, as evidenced by the reduction in malondialdehyde and enhanced activities of antioxidant enzymes in serum. These data indicate that heat-killed M. phlei is a promising alternative to antibiotic use for early weaned piglets via induction of protective immune responses.     

Dose-dependent effects of two inulin types differing in chain length on the small intestinal morphology,contractility and proinflammatory cytokine gene expression in piglets

ABSTRACT

Inulin is a linear fructose polymer which may affect small intestinal physiology. The effects of dietary level of two inulin types on morphology, contractility and proinflammatory cytokine gene expression in the small intestine of piglets were investigated. Fifty six piglets were divided into seven groups fed diets without inulin addition or with 1%, 2% or 3% of inulin with an average degree of polymerisation of 10 (IN10) or 23 (IN23). All diets were offered from day 10 of life for 40 d. Feeding IN10 diets did not affect villous height to crypt depth ratio in the duodenum, while in the jejunum the 2% IN10 diet increased it as compared to other groups. Jejunal muscle contractions induced by electrical field stimulation were impaired by the 2% and 3% IN10 diets. The ileal expression of interleukin-12p40 was decreased by the 2% IN10 diet. There was no effect of IN23 level on villous height to crypt depth ratio in any segment of the small intestine as well as on jejunal motility. The 2% and 3% IN23 diets decreased the jejunal expression of tumour necrosis factor-α. In conclusion, IN10 is more active in the small intestine than IN23. At the 2% dietary level, it increases absorptive area in the jejunum, but may slightly impair smooth muscle contractions.     

The growth performance,intestinal digestive and absorptive capabilities in piglets with different lengths of small intestines

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties.     

Heat stress disrupts intestinal stem cell migration and differentiation along the crypt–villus axis through FAK signaling

During heat stress (HS), the intestinal epithelium suffers damage due to imbalance of tissue homeostasis. However, the specific mechanism by which intestinal stem cells (ISCs) migrate and differentiate along the crypt–villus axis to heal lesions upon insult is unclear. In our study, C57BL/6 mice and IPEC-J2 cells were subjected to normal ambient conditions (25 °C for 7 days in vivo and 37 °C for 18 h in vitro) or 41 °C. The results showed that HS impaired intestinal morphology and barrier function. The numbers of ISCs (SOX9⁺ cells), mitotic cells (PCNA⁺ cells), and differentiated cells (Paneth cells marked by lysozyme, absorptive cells marked by Villin, goblet cells marked by Mucin2, enteroendocrine cells marked by Chromogranin A, and tuft cells marked by DCAMKL1) were reduced under high temperature. Importantly, BrdU incorporation confirmed the decreased migration ability of jejunal epithelial cells exposed to 41 °C. Furthermore, intestinal organoids (IOs) expanded from jejunal crypt cells in the HS group exhibited greater growth disadvantages. Mechanistically, the occurrence of these phenotypes was accompanied by FAK/paxillin/F-actin signaling disruption in the jejunum. The fact that the FAK agonist ZINC40099027 reversed the HS-triggered inhibition of IPEC-J2 cell differentiation and migration further confirmed the dominant role of FAK in response to high-temperature conditions. Overall, the present investigation is the first to reveal a major role of FAK/paxillin/F-actin signaling in HS-induced ISC migration and differentiation along the crypt–villus axis, which indicates a new therapeutic target for intestinal epithelial regeneration after heat injuries.     

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.     

THE COMBINED USE OF WHOLE CUPHEA SEEDS CONTAINING MEDIUM CHAIN FATTY ACIDS AND AN EXOGENOUS LIPASE IN PIGLET NUTRITION

In search for an alternative for nutritional antimicrobials in piglet feeding, the effects of adding whole Cuphea seeds, as a natural source of medium chain fatty acids (MCFA), with known antimicrobial effects, and an exogenous lipase to a weaner diet were studied. The foregut flora, the gut morphology, some digestive parameters and the zootechnical performance of weaned piglets were investigated. Thirty newly weaned piglets, initial weight 7.0 ± 0.4 kg, were divided according to litter, sex and weight in two groups (control diet; Cuphea+lipase diet). The Cuphea seeds (lanceolata and ignea) (50 g kg^?1) were substituted for soybean oil (15 g kg^?1), Alphacell (25 g kg^?1) and soy protein isolate (10 g kg^?1) in the control diet. Also 500 mg kg^?1 microbial lipase was added to the Cuphea diet. The piglets were weighted individually on days 0, 3, 7, 14 and 16. Feed intake was recorded per pen during days 0 to 3, 3 to 7, 7 to 14 and 14 to 16. On day 7 five piglets of each experimental group were euthanized for counting the gastric and small intestinal gut flora and for gut morphology at two sites of the small intestine (proximal, distal). The results indicate a trend towards improved performances parameters by feeding Cuphea + lipase. The enzymic released MCFA (1.7 g kg^?1 fresh gastric contents) tended to decrease the number of Coliforms in the proximal small intestine, but increased the number in the stomach and distal small intestine. With Cuphea, the number of Streptococci was significantly lower in small intestine, but not in the stomach, while the number of Lactobacilli was significantly lower in the distal small intestine and tended to be lower in the stomach and proximal small intestine. No differences between the diets were noted for the total anaerobic microbial load in the stomach or in the gut. Feeding Cuphea+lipase resulted in a significantly greater villus height (distal small intestine) and a lesser crypt depth (proximal and distal small intestine) and greater villus/crypt ratio depth (proximal and distal small intestine). The intra-epithelial lymphocyte (IEL) counts per 100 enterocytes were significantly decreased in the proximal small intestine and tended to decrease in the distal small intestine by feeding the Cuphea+lipase diet. Both phenomena are indicative for a more healthy and better functional state of the mucosa. Present results are in line with foregoing research, showing that manipulation of the gut ecosystem by the enzymic in situ released MCFA in the stomach and foregut can result in improved performances of the piglets, which makes the concept a potential alternative for in-feed nutritional antibiotics.     

Expression of porcine epidermal growth factor in Pichia pastoris and its biology activity in early-weaned piglets

Early-weaned piglets often have abnormalities in intestinal morphology and function. Epidermal growth factor (EGF) is critical in the development and in the repair of the gastrointestinal tract in pigs. This study investigated the effects of dietary EGF supplementation on growth performance and small intestinal morphology of early-weaned piglets. The functional domain of porcine EGF (pEGF) was cloned after RT-PCR amplification. The recombinant protein was expression by the Pichia pastoris expression system and the construct pPIC9K-pEGF was transformed into host GS115. The secretary recombinant protein in the supernatants was analyzed by SDS-PAGE. The gel indicated that the extra band at 6 kDa in the transformant, which corresponds to the standard hEGF, were both reactive to anti-pEGF antibody by Western blotting. The expression level of pEGF in the culture supernatant was 870 microg/mL. An animal feeding test was conducted to identify the effects of pEGF supplementation on growth performance and the development of digestive tracts of 14-day weaned piglets. The dietary treatment was a corn-soybean meal basal diet either with or without 1.5 mg/kg recombinant pEGF from the transformant fermentative supernatant. Dietary treatments enhanced the daily gain during 0-7 days postweaning (p < 0.05), but did not affect the performance throughout the entire test period. Dietary supplemental pEGF significantly increased serum IgA levels on day 18 postweaning, and increased the mucosa IgA levels and crypt depth at jejunum on day 28 postweaning (p < 0.05). The experimental results showed that the recombinant pEGF could be secreted by P. pastoris. The trophic effects of pEGF on growth performance, immune response, and small intestine development were determined by feeding recombinant pEGF to early-weaned piglets.     

Dietary Lactobacillus rhamnosus GG Supplementation Improves the Mucosal Barrier Function in the Intestine of Weaned Piglets Challenged by Porcine Rotavirus

Lactobacillus rhamnosus GG (LGG) has been regarded as a safe probiotic strain. The aim of this study was to investigate whether dietary LGG supplementation could alleviate diarrhea via improving jejunal mucosal barrier function in the weaned piglets challenged by RV, and further analyze the potential roles for apoptosis of jejunal mucosal cells and intestinal microbiota. A total of 24 crossbred barrows weaned at 21 d of age were assigned randomly to 1 of 2 diets: the basal diet and LGG supplementing diet. On day 11, all pigs were orally infused RV or the sterile essential medium. RV infusion increased the diarrhea rate, increased the RV-Ab, NSP4 and IL-2 concentrations and the Bax mRNA levels of jejunal mucosa (P<0.05), decreased the villus height, villus height: crypt depth, the sIgA, IL-4 and mucin 1 concentrations and the ZO-1, occludin and Bcl-2 mRNA levels of jejunal mucosa (P<0.05), and affected the microbiota of ileum and cecum (P<0.05) in the weaned pigs. Dietary LGG supplementation increased the villus height and villus height: crypt depth, the sIgA, IL-4, mucin 1 and mucin 2 concentrations, and the ZO-1, occludin and Bcl-2 mRNA levels of the jejunal mucosa (P<0.05) reduced the Bax mRNA levels of the jejunal mucosa (P<0.05) in weaned pigs. Furthermore, dietary LGG supplementation alleviated the increase of diarrhea rate in the weaned pigs challenged by RV (P<0.05), and relieve the effect of RV infection on the villus height, crypt depth and the villus height: crypt depth of the jejunal mucosa (P<0.05), the NSP4, sIgA, IL-2, IL-4, mucin 1 and mucin 2 concentrations of jejunal mucosa (P<0.05), the ZO-1, occludin, Bax and Bcl-2 mRNA levels of the jejunal mucosa (P<0.05), and the microbiota of ileum and cecum (P<0.05) in the weaned pigs challenged by RV. These results suggest that supplementing LGG in diets alleviated the diarrhea of weaned piglets challenged by RV via inhibiting the virus multiplication and improving the jejunal mucosal barrier function, which was possibly due to the decreasing apoptosis of jejunal mucosal cells and the improvement of intestinal microbiota.