Effects of Marigold Flavonoids on Growth Performance,Nutrient Apparent Digestibility,Serum Antioxidant and Immune Indices of Heat Stressed Beef Cattle
This experiment was conducted to investigate the effects of marigold flavonoids on growth perform-ance,nutrient apparent digestibility,serum antioxidant and immune indices of heat stressed beef cattle.Sixty healthy Simmental bulls without disease were randomly divided into 4 groups with 15 bulls per group according to the principle of similar body weight[(518.32±25.59)kg].The control group(M0 group)was fed a total mixed ration(TMR),and the experimental groups were fed the TMR supplemented with 3(M3 group),6(M6 group)and 9 g/(d·head)(M9 group)marigold flavonoids,respectively.The experiment lasted for a total of 67 days,including 7 days of pre-feeding and 60 days of formal feeding.The average temperature and humidity index was 80.06 during the experiment,and beef cattle were in a state of moderate heat stress.The results showed as follows:1)compared with M0 group,the respiratory rate of M6 group on day 40 was sig-nificantly decreased(P＜0.05).2)Compared with M0 group,the average daily gain(ADG)of M3 and M6 groups was significantly increased(P＜0.05),and the ratio of feed to gain(F/G)was significantly decreased(P＜0.05).3)On day 60,compared with M0 group,the dry matter(DM)apparent digestibility of M6 and M9 groups was significantly increased(P=0.05),the crude protein(CP)apparent digestibility of M6 group was significantly increased(P＜0.05),and the calcium(Ca)and phosphorus(P)apparent digestibility of M3 and M6 groups was significantly increased(P≤0.05).4)On day 60,compared with M0 group,the serum malondialdehyde(MDA)content of M3 and M6 groups was significantly decreased(P＜0.05),and the serum total antioxidant capacity(T-AOC)of M6 group was significantly increased(P=0.05).5)On day 60,com-pared with M0 group,the contents of immunoglobulin A(IgA)and interleukin-2(IL-2)in serum of M3,M6 and M9 groups were significantly increased(P＜0.05),and the serum tumor necrosis factor-α(TNF-α)con-tent of M6 group was significantly decreased(P＜0.05).In conclusion,dietary supplementation of marigold flavonoids can effectively reduce the respiratory rate of heat-stressed beef cattle,improve growth performance,enhance the body antioxidant capacity and immune function,and the supplementation of 6 g/(d·head)mari-gold flavonoids has the best effect.[Chinese Journal of Animal Nutrition,2024,36(9):5736-5747]
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维普
