Study On Effects Of Soybean Bioactive Peptides On Growth Performance And Mechanism In Weanling Pigs

This research centered on the effects of soybean peptides on growth performance of weanling piglets. Furthermore, the mechanism of these effects was investigated on aspects of immunology, intestinal histology and gut micro-flora.Experiment 1: Effects of soybean oligopeptides (SBP) on growth performance of weanling pigs240 35-days-old cross-bred (DoricXLandraceXLarge White) weaned piglets with initial weight at 8.78 + 0.98kg were randomly allotted to five treatments with six replicates per treatment and eight pigs per pen (four gilts and four barrows) at similar initial body weight. Basal diet was fed to the control group and basal diet+75mg/kg Aureomycin, 1000mg/kg SBP, 3000mg/kg SBP, 5000mg/kg SBP supplement to other experimental groups, respectively. Results showed that addition of 3000mg/kg SBP significantly increased ADG and decreased feed/gain efficiency (P<0.05) while diarrhea incidences were significantly decreased by the addition of 1000mg/kg SBP (P<0.05) . As for ADFI, the differences among all groups were not significant. Experiment 2: Effects of SBP on growth performance of young growing pigs192 70-days-old cross-bred (DoricXLandraceXLarge White) young growing pigs with initial weight at 16.68 +0.67kg were randomly allotted to three treatments with four replicates per treatment and sixteen pigs per pen (four gilts and four barrows) at similar initial body weight. Basal diet was fed to the control group and basal diet +75mg/kg Aureomycin, 3000mg/kg SBP supplement to other experimental groups, respectively. Results showed that addition of 3000mg/kg SBP increased ADG and decreased feed/gain efficiency by a certain amount which was better than the other two groups on a non-significant level (P>0.05). Experiment 3: Mechanism of the growth-promoting effects on weanling pigs of SBPThe design of this experiment was the same as that of experiment 1, and aimed at discovering the mechanism of the effects showed in the former two experiments by means of immunology, intestinal histology and gut microbiology. The pigs were inoculated by BSA twice to ensure the animals could produce high levels of antibodies in the blood. Four pigs from each of the control group, Aureomycin group and 3000mg/kg SBP group were slaughtered after 25 days of experiment. The results showed that SBP added up to the level of blood antibodies and might affect increasingly or decreasingly to different stains in cecum and colon. The main inhibiting effects appeared on aerobes (E. coli and salmonella), while lactobacilli were promoted in the colon. At the same time, intestinal mucosal villi were heightened and crypts were deepened significantly in the SBP groups, and the percentage of goblet cell was increased ultra significantly as well.