不同比例巨菌草青贮对肉牛生产性能、养分表观消化率和血清生化指标的影响OA

[Objective]This experiment was conducted to investigate the effects of Pennisetum giganteum silage at different proportions on growth performance,apparent nutrient digestibility,serum biochemical,immune function,and antioxidant indices in beef cattle,and determine the optimal additional proportion of Pennisetum giganteum silage.[Method]A single-factor completely randomized design was used,fifty healthy Simmental crossbred(F1)beef cattle aged 11-12 months with an body weight of 251.08 kg±51.54 kg were randomly allocated to 5 groups:Control group and experimental groups Ⅰ,Ⅱ,Ⅲ,and Ⅳ.Pennisetum giganteum silage was supplemented to the basal diet at 0(control),5%,10%,15%,and 20%,respectively.The total trial lasted 73 d,consisting of a 7 d adaptation period,a 60 d feeding trial period,and a 6 d digestibility trial period.Initial body weight(IBW)and final body weight(FBW)were recorded to calculate average daily gain(ADG).Average daily feed intake(ADFI)and feed-to-gain ratio(F/G)were determined by daily measurement of feed offered and refusals.On the 60th day of the trial period,blood samples were collected from the caudal vein of each cattle to analyze serum biochemical,immune,and antioxidant indices.During the digestibility trial,fecal and feed samples were collected daily for the determination of nutrient apparent digestibility.[Result]Compared with control group:① Supplementing of Pennisetum giganteum silage had no significant effect on the growth performance of beef cattle(P>0.05).②The apparent nutrient digestibility of dry matter(DM),organic matter(OM),and crude protein(CP)in diet of beef cattle in groups Ⅱ,Ⅲ,and Ⅳ were extremely significantly or significantly increased(P<0.01 or P<0.05).③ The levels of globulin(GLB),low-density lipoprotein(LDL),and lactate dehydrogenase(LDH)in serum of beef cattle in group Ⅳ were significantly increased(P<0.05).④The immune indices of IgA,IgG,and IgM in serum of beef cattle in groups Ⅲ and Ⅳ were extremely significantly or significantly increased(P<0.01 or P<0.05).⑤The total antioxidant capacity(T-AOC),and the activities of catalase(CAT),superoxide dismutase(SOD),and glutathione peroxidase(GSH-Px)in serum of beef cattle in groupsⅡ,Ⅲ,and Ⅳ were extremely significantly or significantly increased(P<0.01 or P<0.05),while malondialdehyde(MDA)content was extremely significantly decreased(P<0.01).[Conclusion]Under the conditions of this experiment,dietary addition with 10%Pennisetum giganteum silage could reduce F/G and improve apparent nutrient digestibility in beef cattle.Dietary addition with 15%-20%Pennisetum giganteum silage were more beneficial to enhance the immune function and antioxidant capacity in beef cattle.Considering the core goal of production efficiency,10%was recommended as the optimal additional level of Pennisetum giganteum silage in diet for beef cattle.