Supplementation of diets for lactating sows with zinc amino acid complex and gastric nutriment‐intubation of suckling pigs with zinc methionine on mineral status,intestinal morphology and bacterial translocation in lipopolysaccharide‐challenged weaned pigs

Sixty‐four pigs from 16 sows were used to evaluate addition of zinc amino acid complex (ZnAA) to lactating sows and gastric nutriment‐intubation of zinc methionine (ZnMet) to suckling pigs on mineral status, intestinal morphology and bacterial translocation after weaning. Sows were fed a barley‐based diet supplying 120 ppm zinc (Zn; control) or the control diet supplemented with 240 ppm Zn from ZnAA. At birth, day‐10 and day‐21 (weaning) of age, pigs from each litter were nutriment‐intubated with 5 ml of an electrolyte solution without or with 40 mg Zn from ZnMet. At weaning, 24 h prior to the collection of small and large intestinal lymph nodes and sections of the duodenum, jejunum and ileum, the pigs received an intramuscular injection of saline without or with 150 μg/kg body weight of Escherichia coli O26:B6 lipopolysaccharide (LPS). With the exception of a tendency (p = 0.09) for lower serum concentration of copper in pigs at weaning from ZnAA‐supplemented sows, there were no differences (p > 0.1) than for pigs from control‐fed sows for mineral status or intestinal morphology. Nutriment‐intubation of ZnMet increased serum (p = 0.001) and liver (p = 0.003) Zn concentrations, number of goblet cells per 250 μm length of jejunal villous epithelium (p = 0.001) and tended (p = 0.06) to enhance jejunum mucosa thickness. Interactive effects (p < 0.05) for higher jejunal villi height and villi:crypt ratio and increased ileal goblet cell counts were apparent for pigs from ZnAA‐supplemented sows that also received nutriment‐intubation of ZnMet. Challenge with LPS increased (p = 0.05) ileal villous width. Nutriment‐intubation of ZnMet decreased (p = 0.05) anaerobic bacteria colony forming unit counts in the large intestinal mesenteric lymph nodes. In conclusion, nutriment‐intubation of ZnMet increased serum and liver tissue concentrations of Zn and resulted in limited improvement to intestinal morphology of weaned pigs.     

Gastrointestinal health and function in weaned pigs: a review of feeding strategies to control post‐weaning diarrhoea without using in‐feed antimicrobial compounds

For the last several decades, antimicrobial compounds have been used to promote piglet growth at weaning through the prevention of subclinical and clinical disease. There are, however, increasing concerns in relation to the development of antibiotic‐resistant bacterial strains and the potential of these and associated resistance genes to impact on human health. As a consequence, European Union (EU) banned the use of antibiotics as growth promoters in swine and livestock production on 1 January 2006. Furthermore, minerals such as zinc (Zn) and copper (Cu) are not feasible alternatives/replacements to antibiotics because their excretion is a possible threat to the environment. Consequently, there is a need to develop feeding programs to serve as a means for controlling problems associated with the weaning transition without using antimicrobial compounds. This review, therefore, is focused on some of nutritional strategies that are known to improve structure and function of gastrointestinal tract and (or) promote post‐weaning growth with special emphasis on probiotics, prebiotics, organic acids, trace minerals and dietary protein source and level.     

Effects of dietary methionine supplementation on growth performance,intestinal morphology,antioxidant capacity and immune function in intra‐uterine growth‐retarded suckling piglets

This study investigated the effects of dietary supplementation with _L‐methionine (_L‐Met), _DL‐methionine (_DL‐Met) and calcium salt of the methionine hydroxyl analog (MHA‐Ca) on growth performance, intestinal morphology, antioxidant capacity and immune function in intra‐uterine growth‐retarded (IUGR) suckling piglets. Six normal birthweight (NBW) female piglets and 24 same‐sex IUGR piglets were selected at birth. Piglets were fed nutrient adequate basal diet supplemented with 0.08% _L‐alanine (NBW‐CON), 0.08% _L‐alanine (IUGR‐CON), 0.12% _L‐Met (IUGR‐LM), 0.12% _DL‐Met (IUGR‐DLM) and 0.16% MHA‐Ca (IUGR‐MHA‐Ca) from 7 to 21 days of age respectively (n = 6). The results indicated that IUGR decreased average daily milk (dry matter) intake and average daily gain and increased feed conversion ratio of suckling piglets (p < 0.05). Compared with the NBW‐CON piglets, IUGR also impaired villus morphology and reduced antioxidant capacity and immune homeostasis in the intestine of IUGR‐CON piglets (p < 0.05). Supplementation with _L‐Met enhanced jejunal villus height (VH) and villus area and ileal VH of IUGR piglets compared with IUGR‐CON piglets (p < 0.05). Similarly, _DL‐Met supplementation increased VH and the ratio of VH to crypt depth in the jejunum compared with IUGR‐CON pigs (p < 0.05). Supplementation with _L‐Met and _DL‐Met (0.12%) tended to increase reduced glutathione content and reduced glutathione: oxidized glutathione ratio and decrease protein carbonyl concentration in the jejunum of piglets when compared with the IUGR‐CON group (p < 0.10). However, supplementation with MHA‐Ca had no effect on the intestinal redox status of IUGR piglets (p > 0.10). In conclusion, supplementation with either _L‐Met or _DL‐Met has a beneficial effect on the intestinal morphology and antioxidant capacity of IUGR suckling piglets.     

Dietary supplementation of plant essential oil improves growth performance,intestinal morphology and health in weaned pigs

The present study was conducted to explore the effect of plant essential oil (PEO) on growth performance, intestinal morphology and health in weaned pigs. Twenty-four weaned pigs were assigned into four groups fed with a basal diet (CON) or basal diet containing PEO at a concentration of 50 (PEO50), 100 (PEO100) or 200 ppm (PEO200). After 21 days, pigs were slaughtered and blood and tissue samples were collected. Result showed that PEO200 group significantly increased the average daily gain (ADG) compared with CON group (p < .05). Moreover, PEO supplementation significantly improved the digestibility of DM (p < .05). However, it significantly decreased the serum triglyceride and cholesterol concentration (p < .05). Interestingly, PEO supplementation significantly increased the activity of sucrase in the duodenal and the activity of lactase in the jejunal mucosa (p < .05). Moreover, PEO supplementation improved the growth of intestinal mucosa. As compared to the CON group, the jejunum and ileum villus height were significantly elevated in the PEO200 group (p < .05). Importantly, the expression levels of critical genes associated with nutrient transportation (i.e., GLUT2 and SGLT1) and barrier function (occludin) were significantly elevated in the PEO200 group (p < .05). Moreover, the PEO100 and PEO200 group had higher propionic acid concentration and higher total bacterial gene copies in colon digesta than the CON group (p < .05) respectively. These results not only suggest that PEO has a positive role in the regulation of growth and intestinal health in weaned pigs, but also offer a potential candidate substituting the conventionally used antibiotics in the livestock industry.     

Effects of Armillariella tabescens mycelia on the growth performance and intestinal immune response and microflora of early‐weaned pigs

This study was performed to evaluate effects of Armillariella tabescens (A. tabescens) on the growth performance and intestinal immune response and microflora in early‐weaned pigs when used as feed additive. A. tabescens mycelia were added to basal diets at concentrations of 0%, 0.1%, 0.3% or 0.9% (w/w). A total of 144 commercial cross‐bred piglets were randomly allocated to one of these four diets and fed for 30 days. The growth performance of early‐weaned piglets displayed improvement with diets containing 0.1% and 0.3% dried mycelia powder from A. tabescens. Supplementing with 0.1% or 0.3% A. tabescens mycelia induced a 2.6‐ and three‐fold increase in secretory immunoglobulin A (sIgA) content in the jejunal mucosa, respectively, but had only a marginal effect on sIgA in the ileal mucosa. Expression of interleukin‐2, interferon‐γ, and tumor necrosis factor‐α in the jejunal mucosa were elevated with A. tabescens mycelia administration. Increased amounts of Lactobacillus spp. and Bifidobacterium spp. in the jejunum, and decreased amounts of Escherichia coli in the jejunum and ileum were observed with the administration of A. tabescens‐containing diets. This study demonstrated that A. tabescens had beneficial effects on the growth performance and intestinal microflora of early‐weaned pigs.     

Medium‐chain triglyceride as an alternative of in‐feed colistin sulfate to improve growth performance and intestinal microbial environment in newly weaned pigs

Five hundred and twenty‐eight newly weaned pigs were given four treatments, with eight replicates per treatment. Sixteen to 18 pigs were assigned per replicate and were fed diets supplemented with 0 or 3% medium‐chain triglyceride (MCT) and 0 or 40 ppm colistin sulfate (CS) in a 2 × 2 factorial arrangement for 2 weeks. The results showed that dietary supplementation with MCT improved the gain‐to‐feed ratio during days 3‐7 and in the overall period (P < 0.05). Dietary supplementation with MCT decreased coliforms counts (C) in colon and rectum content (P < 0.05). Dietary supplementation with CS decreased C and lactic acid bacteria plus C counts (L + C) in cecum (P < 0.05), and C, L + C (P < 0.01) and ratio of L and C (P < 0.05) in colon and rectum contents. The lack of interactions between MCT and CS indicates different modes of action and additive effects between the two supplementations. In conclusion, supplementation with MCT in diet with or without CS could improve the intestinal microbial environment and the feed utilization efficiency of newly weaned pigs.     

Functional roles of xylanase enhancing intestinal health and growth performance of nursery pigs by reducing the digesta viscosity and modulating the mucosa-associated microbiota in the jejunum

This study was conducted to investigate the functional roles of an endo-β-1,4-xylanase on the intestinal health and growth performance of nursery pigs. A total of 60 pigs (21 d old, 6.9 ± 0.8 kg body weight [BW]) were allotted based on a randomized complete block design with sex and initial BW as blocks. Dietary treatments had nutrients meeting the requirements with increasing levels of endo-β-1,4-xylanase (0, 220, 440, 880, 1,760 xylanase unit [XU] per kg feed) and fed to pigs in three phases (phases 1, 2, and 3 for 10, 14, and 14 d, respectively). Titanium dioxide (0.4%) was added to the phase 3 diets as an indigestible marker. On day 38, all pigs were euthanized to collect ileal digesta to measure apparent ileal digestibility (AID), jejunal digesta to measure viscosity, and jejunal mucosa to evaluate intestinal health. Data were analyzed using the MIXED procedure for polynomial contrasts and the NLMIXED procedure for broken line analysis of SAS. Increasing xylanase in the nursery diets reduced (linear, P < 0.05) the digesta viscosity in the jejunum. Increasing xylanase tended to reduce the relative abundance of Cupriavidus (P = 0.073) and Megasphaera (P = 0.063); tended to increase the relative abundance of Succinivibrio (P = 0.076) and Pseudomonas (P = 0.060); and had a quadratic effect (P < 0.05) on the relative abundance of Acinetobacter (maximum: 2.01% at 867 XU per kg feed). Xylanase from 0 to 1,087 XU per kg feed reduced (P < 0.05) jejunal malondialdehyde. Xylanase from 0 to 1,475 XU per kg feed increased (P < 0.05) the AID of neutral detergent fiber. Increasing xylanase increased (P < 0.05) the AID of ether extract and tended to increase (P = 0.058) the AID of crude protein. Increasing xylanase did not affect growth performance on overall period, whereas xylanase from 0 to 736 XU per kg feed increased (P < 0.05) average daily gain (ADG) during days 31 to 38. In conclusion, xylanase supplementation showed benefits on intestinal health by reducing digesta viscosity, the relative abundance of potentially harmful bacteria, and the oxidative stress in the jejunal mucosa, collectively enhancing intestinal morphology and the AID of nutrients. Xylanase supplementation at a range of 750 to 1,500 XU per kg feed provided benefits associated with reduced oxidative stress, increased nutrient digestibility, resulting in potential improvement on growth performance of nursery pigs by increasing the average daily feed intake and moderately improving the ADG throughout the last week of feeding.     

Effects of dietary supplementation with epidermal growth factor on nutrient digestibility,intestinal development and expression of nutrient transporters in early‐weaned piglets

The abnormalities in intestinal morphology and digestive function during weaning are associated with the loss of milk‐borne growth factors. Epidermal growth factor (EGF) has been shown to stimulate the growth of animals. This study was to determine the effect of dietary EGF on nutrient digestibility, intestinal development and the expression of genes encoding nutrient transporters in weaned piglets. Forty‐two piglets were weaned at 21 days and assigned to one of three treatment groups: (1) basal diet (control), (2) basal diet + 200 µg/kg EGF or (3) basal diet + 400 µg/kg EGF. Each treatment consisted of 14 replicates, and seven piglets from each treatment were sampled on day 7 and 14. The EGF supplementation significantly elevated (p < 0.05) the coefficients of total tract apparent digestibility of crude protein, calcium and phosphorus, but tended to decrease sucrase activity (p < 0.10) than the control group. At day 7 post‐weaning, animals receiving EGF diets showed a tendency (p < 0.10) towards greater ileal villus height (VH), jejunal crypt depth (CD) and duodenal VH:CD when compared with the control group. Moreover, the mRNA levels of glucose transporter 2 (Slc2a2), neutral amino acid transporter (Slc6a19) and calbindin D9k (S100G) tended to be higher (p < 0.10) for EGF groups than the control group. By day 14, EGF supplementation markedly enhanced (p < 0.05) the VH, CD and VH:CD in the jejunum compared to the control group. This addition also up‐regulated (p < 0.05) the mRNA level and the protein abundance of peptide transporter 1 than the control group. These findings demonstrated that dietary EGF beneficially enhanced nutrient digestibility, improved intestinal development and increased the mRNA expression of nutrient transporters in weaned piglets.     

Effect of pectin oligosaccharides and zinc chelate on growth performance,zinc status,antioxidant ability,intestinal morphology and short‐chain fatty acids in broilers

A 42‐day trial was conducted to investigate the effect of pectin oligosaccharides (POS) and zinc chelate (Zn‐POS) on growth performance, antioxidant ability, zinc status, intestinal morphology and short‐chain fatty acids in broilers. A total of 324 1‐day‐old Arbor Acres broilers were randomly assigned to three treatments with six cages of 18 chicks. Treatments were: (a) Control, 80 mg/kg Zn from ZnSO₄; (b) POS, 80 mg/kg Zn from ZnSO₄ + 482 mg/kg POS (the same amount of POS as treatment 3); and (c) Zn‐POS, 80 mg/kg zinc from Zn‐POS. Compared to the Control, both POS and Zn‐POS supplementation increased average daily gain and reduced the mortality during day 22–42, and only Zn‐POS supplementation decreased the ratio of feed to gain during day 22–42 and 1–42. Moreover, both POS and Zn‐POS supplementation improved Zn status and gut function as evidenced by increased metallothionein concentrations in the pancreas, villus height in the duodenum and isobutyrate concentrations in the caecal digesta. Additionally, Zn‐POS supplementation increased gene expressions of metallothionein, Zn transporter 1, Zn transporter 2 in the pancreas, nuclear factor erythroid 2‐related factor 2 in the liver, the concentrations of acetate, propionate, butyrate and total SCFA in the caecal digesta and the villus height to crypt depth ratio in the duodenum and jejunum, whereas decreased the crypt depth in these two tissues. Altogether, our results revealed that dietary POS or Zn‐POS supplementation benefited growth performance, Zn status, antioxidant ability and gut function of broilers. Supplementing Zn‐POS in the form of chelate was more effective than feeding POS or ZnSO₄ separately.     

Modulation of jejunal mucosa-associated microbiota in relation to intestinal health and nutrient digestibility in pigs by supplementation of β-glucanase to corn–soybean meal-based diets with xylanase

This study aimed to evaluate the effects of increasing levels of β-glucanase on the modulation of jejunal mucosa-associated microbiota in relation to nutrient digestibility and intestinal health of pigs fed diets with 30% corn distiller’s dried grains with solubles and xylanase. Forty pigs at 12.4 ± 0.5 kg body weight (BW) were allotted in a randomized complete block design with initial BW and sex as blocks. Dietary treatments consisted of a basal diet with xylanase (1,500 endo-pentosanase units [EPU]/kg) and increasing levels of β-glucanase (0, 200, 400, and 600 U/kg) meeting nutrient requirements and fed to pigs for 21 d. Blood samples were collected on day 19. On day 21, all pigs were euthanized to collect intestinal tissues and digesta. Tumor necrosis factor-alpha, interleukin (IL)-6, and malondialdehyde were measured in the plasma and mid-jejunal mucosa. Viscosity was determined using digesta from the distal jejunum. Ileal and rectal digesta were evaluated to determine apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients. Mucosa samples from the mid-jejunum were utilized for microbiota sequencing. Data were analyzed using the MIXED procedure on SAS 9.4. Overall, increasing dietary β-glucanase tended to increase (linear; P = 0.077) the average daily gain of pigs. Increasing dietary β-glucanase affected (quadratic; P < 0.05) the relative abundance of Bacteroidetes, reduced (linear; P < 0.05) Helicobacter rappini, and increased (linear, P < 0.05) Faecalibacterium prausnitzii. β-Glucanase supplementation (0 vs. others) tended to increase (P = 0.096) the AID of crude protein in the diet, whereas increasing dietary β-glucanase tended to increase (linear; P = 0.097) the ATTD of gross energy in the diet and increased (linear; P < 0.05) the concentration of IL-6 in the plasma of pigs. In conclusion, increasing β-glucanase up to 600 U/kg feed in a diet containing xylanase (1,500 EPU/kg) modulated mucosa-associated microbiota by increasing the relative abundance of beneficial bacteria and reducing potentially harmful bacteria. Furthermore, increasing β-glucanase up to 600 U/kg feed in a diet containing xylanase (1,500 EPU/kg feed) enhanced the status of the intestinal environment and nutrient utilization, as well as reduced systemic inflammation of pigs, collectively resulting in moderate improvement of growth performance. Supplementing β-glucanase at a range of 312 to 410 U/kg with xylanase at 1,500 EPU/kg feed showed the most benefit on jejunal mucosa-associated microbiota and reduced systemic inflammation of pigs.     

Effects of essential oil supplementation of a low‐energy diet on performance,intestinal morphology and microflora,immune properties and antioxidant activities in weaned pigs

A total of 144 weaned piglets were used to evaluate the effects of essential oil (EO) supplementation of a low‐energy diet on performance, apparent nutrient digestibility, small intestinal morphology, intestinal microflora, immune properties and antioxidant activities in weaned pigs. Pigs received a low‐energy diet (negative control, NC, digestible energy = 3250 kcal/kg), NC plus 0.025% EO or a positive control diet (PC, digestible energy = 3400 kcal/kg) for 28 days. Growth performance was similar between the EO group and PC group. However, EO supplementation increased (P < 0.05) average daily gain and the apparent digestibility of dry matter, crude protein and energy compared with pigs fed the NC diet. Greater (P < 0.05) villus height and lower (P < 0.05) counts of Escherichia coli and total anaerobes in the rectum in the EO group were observed compared with NC or PC groups. Pigs fed EO diet had higher (P < 0.05) concentrations of albumin, immunoglobulin A (IgA), IgG and total antioxidant capacity and lower fecal score than pigs fed the PC and NC diets. Above all, this study indicates that supplementation of EO to a low‐energy pig diet has beneficial results and obtains similar performance compared with normal energy (PC) diet.