Effects of Two Nutrient Level Diets on Growth Performance,Nutrient Apparent Digestibility,Serum Biochemical Indices and Fecal Microflora of Two Breeds of Cattle
This experiment was conducted to investigate the effects of two nutrient levels on growth perform-ance,nutrient apparent digestibility,serum biochemical indices and fecal microflora of two breeds of growing cattle.In a 2×2 two-factor randomized experiment design,12 Angus(♂)×Black Simmental(♀)crossbred cattle(Anhei crossbred cattle)and 12 Simmental cattle(half male and half female)with similar age(about 6 months)and body weight[(204.63±23.65)kg]were randomly divided into 2 groups each and fed diets with low nutrient level[the comprehensive net energy(NEmf)was 5.42 MJ/kg and the crude protein(CP)content was 9.66％in the early stage,and NEmf was 5.57 MJ/kg and CP content was 9.05％in the late stage]and high nutrient level(NEmf was 5.77 MJ/kg and CP content was 12.47％in the early stage,and NEmf was 6.00 MJ/kg and CP content was 10.44％in the late stage),respectively.The pre-trial period lasted for 12 days and the trial period lasted for 62 days,which were divided into two stages as the early stage(days 1 to 31)and the late stage(days 32 to 62),and the digestion experiment was conducted on the last 8 days.The re-sults show that:compared with Simmental cattle,the average daily gain(ADG)(P=0.076),apparent di-gestibilities of organic matter(P=0.051)and CP(P=0.087),serum urea nitrogen(UN)content(P=0.077)and glutamic oxalacetic transaminase activity(P=0.070)of Anhei crossbred cattle had a tendency to be increased,the apparent digestibilities of neutral detergent fiber(NDF)and acid detergent fiber(ADF)were significantly increased(P＜0.05).Compared with low nutrient level group,the dry matter intake(DMI)in the early stage,the ADG,DMI,feed conversion rate(FCR)in the late stage and the ADG and DMI during the whole trial period in high nutrient level group were significantly increased(P＜0.05),and the FCR(P=0.085)and serum total cholesterol content(P=0.077)during the whole trial period were tended to be in-creased;the apparent digestibilities of NDF and ADF in low nutrient level group was significantly higher than that in high nutrient level group(P＜0.05).There was significant interaction between breed and nutrient level on serum UN content(P＜0.05).At the phylum level,Firmicutes and Bacteroidetes were the dominant bacteri-al community in fecal microflora of the two breeds of cattle,and there was no significant difference in relative abundance among all groups(P＞0.05).At the genus level,the fecal Turicibacter relative abundance in high nutrient level group was significantly higher than that in low nutrient level group(P＜0.05).In conclusion,the ADG and apparent digestibilities of CP,OM,NDF and ADF of Anhei crossbred cattle are better than Simmen-tal cattle;the high nutrient level diet is more conducive to the relative abundance of intestinal beneficial bacteria and can promote the rapid growth of growing cattle.[Chinese Journal of Animal Nutrition,2024,36(5):3082-3093]
万方数据
维普
