饲粮添加铬对妊娠后期母羊抗氧化能力、免疫功能及乳成分的影响OA

This experiment was conducted to investigate the effects of dietary chromium supplementation on an-tioxidant capacity,immune function and milk composition in late-gestation does,so as to determine the appro-priate dietary chromium supplementation level for pregnant does.Forty multiparous Lezhi black goats at(90±4)days of gestation with similar body weight[(52.36±8.24)kg]and body condition were selected and ran-domly divided into 4 groups with 10 replicates(pens)per group and 1 doe per replicate.The control group was fed a basal diet,and the experimental groups were supplemented with 0.4,1.2 and 2.0 mg/d chromium(in the form of chromium propionate)on the basis of the basal diet,respectively.The experiment lasted for 81 days from day 90 of gestation to day 21 of lactation,including a 7-day pre-experimental period.Blood samples of does were collected on day 120 of gestation,and milk samples were collected on day 1(colostrum),day 3,day 7,day 14 and day 21 of lactation.The results showed as follows:1)dietary chromium supplemen-tation significantly reduced the mortality rate of kids born to does during 1 to 7 days of age and 1 to 21 days of age(P＜0.05),and tended to reduce the mortality rate of kids during 1 to 14 days of age(P=0.074 5),and no dead individuals were found in the group supplemented with 1.2 mg/d chromium.2)Dietary supplementa-tion with different levels of chromium had no significant effects on the serum superoxide dismutase,glutathione peroxidase activities,glucose,urea nitrogen and immunoglobulin A contents of does(P＞0.05);the serum malondialdehyde content had linear and quadratic effects with the increase of dietary chromium supplementation level(P＜0.05),compared with the control group,the serum malondialdehyde content in the group supple-mented with 1.2 mg/d chromium had no significant change(P＞0.05),while that in the group supplemented with 2.0 mg/d chromium was significantly increased(P＜0.05);the serum total protein,immunoglobulin G and immunoglobulin M contents increased linearly with the increase of dietary chromium supplementation level(P＜0.05),and the serum immunoglobulin G and immunoglobulin M contents in the groups supplemented with 1.2 and 2.0 mg/d chromium were significantly higher than those in the control group(P＜0.05).3)The co-lostrum milk fat content of does increased linearly with the increase of dietary chromium supplementation level(P＜0.05),and the colostrum milk fat contents in the groups supplemented with 1.2 and 2.0 mg/d chromium were significantly higher than that in the control group(P＜0.05).It can be concluded that under the conditions of this experiment,the appropriate dietary chromium supplementation level for late-gestation does is 1.2 mg/d;this supplementation level can significantly improve the immune function of does and effectively increase the colostrum milk fat content.[Chinese Journal of Animal Nutrition,2026,38(3):2086-2094]