Effects Of Compound Bacteria Culture And Yeast Polysaccharide On Immune Function Of Lambs

In the production of lamb breeding,factors such as weaning stress,incomplete immunization and lamb diarrhea are all important reasons for the low immunity of lambs.Yeast and its cultures have shown positive effects in improving the immune function of animals.The compound bacteria culture is a microecological preparation developed by our research group based on the physiological characteristics of ruminants.It has functions in regulating the intestinal microecological balance,improving the immune function,anti-inflammatory,anti-oxidation,and increasing the daily feed intake of animals.This study was conducted to study the effects of compound bacteria culture and yeast polysaccharide on the immune function of lambs.On the basis of this study,the effects of compound bacteria culture and yeast polysaccharide on the immune function of lambs were further compared,which provided reference for the application of compound bacteria culture in lamb breeding.A total of 150 healthy lambs aged 40-50 days were randomly divided into 5 groups.The lambs in the control group was fed with total mixed ration（TMR）,and the ones in the experimental groups I,II,III and IV were fed with TMR supplemented with compound bacteria culture（50g/kg）,yeast cell wall polysaccharide（10g/kg）,β-glucan（2g/kg）and mannan（2g/kg）,respectively.The trial period was 67 days,including 7 days of pre-feeding period and 60 days of formal trial period.Blood samples were collected before morning feeding on the 1st,15th,30th and 60th days of the trial period.The serum contents of interleukin-1β（IL-1β）,IL-2,IL-4,IL-6,tumor necrosis factor-α（TNF-α）,interferon-γ（IFN-γ）,C3 and C4 complements were detected by Elisa.The enzyme activities of lysozyme（LZM）,alkaline phosphatase（AKP）and acid phosphatase（ACP）,as well as the antibody titers of sheep foot-and-mouth disease of serotype O,sheep pox and peste des petits ruminants,were detected.The percentage of T lymphocyte subsets in peripheral blood of lambs was detected by flow cytometry.Before the morning feeding on the 30th day,5 sheep in each group were selected for slaughter,and spleen tissues were taken out.RT-q PCR technology was used to determine the m RNA expression of the immune-related genes.The results were as follows:（1）The compound bacteria culture could significantly increase the contents of IL-1β,IL-2,IL-4,IL-6,TNF-αand IFN-γin the serum of lambs（P<0.05）,and significantly increase the activities of LZM and ACP in the serum of lambs（P<0.05）.The ratio of CD₄⁺/CD₈⁺in peripheral blood of lambs（P<0.05）,and the antibody titers of sheep foot and mouth disease of serotype O,sheep pox and peste des petits ruminants were significantly increased（P<0.05）.The addition of zymosan could significantly increase the contents of IL-4,LZM and ACP in serum and the ratio of CD₄⁺/CD₈⁺in peripheral blood of lambs（P<0.05）.The addition ofβ-glucan significantly increased the contents of IL-4,IFN-γand LZM in serum of lambs（P<0.05）,significantly increased the proportion of CD₄⁺T lymphocytes in peripheral blood of lambs（P<0.05）,and significantly increased the antibody titers of serotype O foot-and-mouth disease and peste des petits ruminants in lambs（P<0.05）.The addition of mannan could significantly increase the content of IL-4 in lamb serum（P<0.05）.The results indicated that adding compound bacteria culture and yeast polysaccharide could improve the immune function of lambs.（2）The addition of compound bacteria culture could significantly up-regulate the m RNA expression of TLR-2,TLR-4,IL-6 and TNF-αin the spleen of lambs（P<0.05）.The results illustrated that the addition of compound bacteria culture may increase the expression of immune-related genes to improve the immune function of the body.In summary,the compound bacteria culture and yeast polysaccharide can improve the immune function of lambs and the expression of immune-related genes in spleen to a certain extent,and the beneficial effects of compound bacteria culture is the best among the four test groups.These results can provide a theoretical basis for the application of compound bacteria culture in lamb breeding.