Study On Effects Of Crude Polysaccharide Of Atractylodes Macrocephala Koidz On Growth And Immune Function For Weaned Piglets

A total of 120 two-line crossbred (Landrace × Yorkshire) 28day weaned piglets(average weight is about 7.5Kg) were randomly assigned to 5 treatments with 3 replicates: 1-based diet group(CR), 2- based diet+antibiotic group(ANT), 3- based diet+0.3% polysaccharide added group(0.3%PAM), 4-based diet+0.6% polysaccharide added group(0.6%PAM), 5-based diet +0.9% polysaccharide added group (0.9%PAM). This experiment had two phases, a total of 28days: the first phase (28d-42d of age), the second phase(42d-56d of age). The objective of this study was to uncover the effects and mechanisms of PAM acting on growth and immune function, so as to provide an theoretical support for exploitation of a this additive. The present research consisted of three parts as follows:1.Effects of PAM on growth performance, biochemical indices, serum IGF-1 concentrations , and gene expression of IGF-1 on liver for weaned piglets The results showed: (1) In the first phase, in contrast to CR and ANT, addition of PAM couldn't affect significantly on ADG , ADFI and F/G (P>0.05). But in the second and total phase, in contrast to CR and ANT, the ADG of 0.6%PAM was increased significantly (P<0.05) .In the second phase, in contrast to CR and ANT, the F/G of 0.6%PAM was decreased significantly(P<0.01), and 0.9%PAM was also decreased significantly(P<0.05). F/G of total phase, 0.6%PAM was the lowest, which was lower than 0.9%PAM (P>0.05). But in contrast to CR, 0.6%PAM was decreased significantly(P<0.01), and in contrast to ANT, it was also decreased significantly (P<0.05).(2) On diarrhea ratio, five groups were concentrate on the first phase, but 0.6% and 0.9%PAM , which were lower than the rest three groups. The highest diarrhea ratio of 0.6%PAM, in contrast to CR and ANT, was decreased 8.37% and 4.2% separately. (3) In contrast to CR, the concentration of serum BUN 0.6%PAM was decreased significantly (P<0.05). The rest five biochemical indices (TP, AMM, CHO, GLU, ALP) among the five groups,the difference were not significant (P>0.05) ,but 0.6%PAM and 0.9%PAM were better than CR and ANT, and the effect of 0.6%PAM was most stable. (4) In the first phase, in contrast to the rest four groups, serum concentration of IGF-1 on the 0.9%PAM was increased significantly (P<0.05),but in the second phase, 0.6%PAM had the highest concentration, the difference among the five groups were not significant(P>0.05). (5)...