Effect Of Lactobacillus On Growth Performance And Mucosal Immunity In Weaned Piglets

The purpose of this study was to evaluate the effects of dietary Lactobacillus plantarum(LP) and Lactobacillus reuteri(LR) on the growth performance, antioxidant capacity and the intestinal health in weaned piglets. One hundred and twenty male piglets[21-day-old, Landrace Large White, average weight of 6.11±0.05 kg] were randomly allocated into 4 groups, with 5 replicates with 6 piglets per replicate, in a complete randomized design. Pigs were fed the basal diet(control group), the basal diet supplemented with 60 mg/kg colistin sulfate and 300 mg/kg chlortetracycline(antibiotic group), the basal diet supplemented with 5 1010CFU/kg LP(LP group), or the basal diet supplemented with 51010CFU/kg LR(LR group), respectively. The experiment lasted for42 days. The results showed that:1) When compared with the control group, LP significantly improved the 42-day-body weight and average daily gain(ADG) during 1-42 d after weaning, while the addition of antibiotic or LR had no significant effect on these indicators. The additions of antibiotic or LR significantly reduced the diarrhea rate of piglets at days 29-42 of the experiment, but there was no significant difference in the diarrhea rate at 1-28 d among treatments.2) The addition of LR significantly down-regulated the m RNA expression of CFTR and NKCC1 in jejunal mucosa, while the addition of antibiotics or LP had no significant effect on the m RNA expression of these two genes.3) The addition of LR and antibiotics could significantly increase the concentration of serum glucose(GLU). The antibiotic group decreased the serum urea nitrogen(SUN)concentration compared with other group, while LP and LR additions did not affect SUN concentration. Both LP and LR additions as well as antibiotic addition had no effect on the concentration of IGF-1 in serum.4) Both LR and LP supplements could significantly reduce the concentrations oflipopolysaccharide(LPS) and Diamine oxidase(DAO) in serum, while the addition of antibiotic had no significant effect on them.5) The serum superoxide dismutase(SOD) concentration was significantly increased in antibiotic group and LP group, while the addition of LR had no effect on it. The additions of antibiotics and LR significantly increased the serum concentration of glutathione peroxidase(GSH-Px), while the addition of LP had no effect on it. Supplementation with antibiotics, LP or LR did not affect serum lactate dehydrogenase(LDH) activity. The supplement of antibiotics and LR, instead of LP, significantly reduced the concentration of malondialdehyde(MDA) in serum.6) LP supplementation had the tendency to increase the jejunal mucosal TLR2 gene expression(P=0.073) in piglets compared to the control group, but the addition of antibiotics and LR had no significant effect on the gene expression of TLR2 in both jejunal mucosa and ileal mucosa. The m RNA expression of TLR4 in jejunum and ileum was not different among treatments.7) Both the additions of LP and LR could significantly down-regulate the m RNA expression of IL-1β in jejunal mucosa, and the addition of antibiotic tend to down-regulated its m RNA expression(P=0.07); the addition of antibiotics significant reduced the protein concentration of IL-1β in jejunal mucosa. The addtion of antibiotics significantly down-regulated the gene expression of IL-6 in jejunal mucosa; the addition of antibiotic and LR significantly reduced the protein concentration of IL-6, while the addition of LP tend to reduced it in jejunal mucosa(P=0.062). The addition of LR could significantly up-regulate the gene expression of TNF-α in jejunal mucosa, and the addition of antibiotics tends to down-regulated the m RNA expression of TNF-α in jejunal mucosa; the addition of LP and LR significantly reduced the protein concentration of TNF-α in jejunal mucosa. The addition of antibiotics and LR significantly increased the gene expression of IFN-γ,and the addition of LP and LP significantly increase the protein concentration of IFN-γ.The addition of LR significantly increased the gene expression and protein concentration of TGF-β in jejunal mucosa.8) Both the addition of antibiotics, LP and LR significantly increased the protein concentration of s Ig A in jejunal mucosa, and the supplement of LR also increased theprotein concentration of s Ig A in ilea mucosa. There was no significant difference in serum Ig G concentration among groups.9) The additions of LP and LR could significantly increase the villus height of the duodenum, and LR addition could remarkably increase the jejunum villus height. The addition of LP could decrease significantly duodenal crypt depth, and additions of antibiotics and LR could both reduce the jejunum crypt depth. Both of the additions of LP and LR increased the duodenum villus height/crypt depth ratio, while antibiotics and LR additions could both significantly increase the villus height/crypt depth ratio in the jejunum.Supplemental antibiotics, LP or LR increased the villus height/crypt depth ratio in the ileum.In conclusion, LR could be the potential in-feed antibiotics alternative in improving the growth performance and enhancingthe intestinal health of weaned piglets, with better effects than LP.