Effects of Different Roughage Source Diets on Nutrient Apparent Digestibility,Intestinal Histomorphology,Immune Indices and Digestive Enzyme Activities of Pre-Weaned Yak Calves
The aim of this experiment was to investigate the effects of different roughage source diets on nutri-ent apparent digestibility,intestinal histomorphology,immune indices and digestive enzyme activities of pre-weaned yak calves.Twenty-one healthy yak calves(male)with similar and body weight[(36.47±0.99)kg]were randomly divided into 3 groups with 7 yak calves in each group.The alfalfa hay group(AH group)was fed milk replacer and starter supplemented with alfalfa hay,the oat hay group(OH group)was fed milk repla-cer and starter supplemented with oat hay,and the mix hay group(AO group)was fed milk replacer and star-ter supplemented with alfalfa hay+oat hay(alfalfa hay:oat hay=1∶1).The pre-experimental period lasted for 21 days,and the experimental period lasted for 120 days.The results showed as follows:1)the apparent di-gestibility of neutral detergent fiber(NDF),acid detergent fiber(ADF),calcium and phosphorus of AO group was significantly higher than that of AH group and OH group(P＜0.05).2)The duodenal villus length of AO group was significantly lower than that of AH group and OH group(P＜0.05),the ileal crypt depth of AO group was significantly higher than that of AH group and OH group(P＜0.05),and the colonic mucosal thickness of AO group and OH group was significantly lower than that of AH group(P＜0.05).3)The jejunal and colonic interferon-γ content and cecal interleukin-1β and secretory immunoglobulin A contents of AO group were significantly higher than those of AH group(P＜0.05),and the colonic secretory immunoglobulin A content of AH group was significantly higher than that of AO group and OH group(P＜0.05).4)The jeju-nal trypsin activity of AO group was significantly higher than that of OH group(P＜0.05),the ileal trypsin and chymotrypsin activities of AO group were significantly higher than those of AH group and OH group(P＜0.05),the jejunal α-amylase activity,duodenal chymotrypsin activity and colonic cellulase activity of OH group were significantly higher than those of AH group and AO group(P＜0.05),and the ileal and colonic α-amylase activity of OH group was significantly higher than that of AO group(P＜0.05).In conclusion,com-pared with single feeding alfalfa hay or oat hay,mixed feeding alfalfa hay and oat hay increase the apparent di-gestibility of NDF,ADF,calcium and phosphorus of yak calves,improve the intestinal main digestive enzyme activities,improve the intestinal immune function,promote the intestinal development,and it is more condu-cive to the early healthy growth of yak calves.[Chinese Journal of Animal Nutrition,2024,36(9):5817-5827]
万方数据
维普
