Effect of sweet sorghum silage replacing maize silage on blood physiology, serum biochemical, and serum antioxidant indexes of sheep

This study investigated the effects of substituting sweet sorghum silage with maize silage in different proportions on sheep health. Fifty healthy sheep were randomly divided into five groups with 10 sheep in each group. Maize silage was replaced with 0 (control), 25%, 50%, 75%, and 100% sweet sorghum silage. Blood physiology and serum biochemical and antioxidant indices of the sheep were determined after feeding for 90 d. The results showed that: 1) substituting sweet sorghum silage with maize silage had no significant effect on daily weight gain and average daily feed intake in sheep, and 2) different treatments had no significant negative effect on the blood physiological indexes of sheep. After 90 d of the experiment, neutrophil ratio(NEUT%) and intermediate cell ratio(MID%) in all groups, white blood cell(WBC) in the 25% group, platelet(PLT) in the control group and 25% group, and platelet hematocrit(PCT) in 25%, 50%, and 75% groups, respectively, were significantly lower than those at the beginning, while lymphocyte ratio(LYM%) in the control group, 25%, and 75% groups, as well as red blood cell(RBC) of 25% and 50% groups, were significantly increased. 3) Serum aspartate transaminase(AST) and alkaline phosphatase(ALP) levels were significantly higher than normal. AST activity in the control group was significantly higher than that in the other groups, with no significant differences among the groups, and the lowest AST activity was observed in the 75% group. The ALP levels in the control group were significantly higher than those in the 50% and 100% groups, and the lowest AST activity was observed in the 100% group. albumin(ALB) and creatinine(CRE) levels in the 75% group were significantly different from those in the 25% group. There were no significant differences in other indices among the groups. 4) The catalase activity(CAT) in the 50% group, total superoxide disumutase(T-SOD) activity in the 100% group, and total antioxidant capacity (T-AOC) in the 75% group were significantly higher than those in the control group. There were no significant differences in the glutathione peroxidase activity(GSH-Px) or malonaldehyde(MDA) content between the groups. In conclusion, substituting corn silage with sweet sorghum silage can improve serum biochemical indices to a certain extent, effectively protect the liver and kidneys, and improve the antioxidant capacity of mutton sheep.