Differences in Small Intestinal Morphology and Digestive Enzyme Activities of Different Breed Lambs

LIU Ming;ZHAO Xingang;ZHANG Can;ZHANG Hao;LUO Hailing;State Key Laboratory of Animal Nutrition,College of Animal Science and Technology,China Agricultural University;College of Food Science &Nutritional Engineering,China Agricultural University;

lambs;;breed;;growth performance;;digestibility;;small intestinal morphology;;digestive enzyme

This study was to explore the differences in small intestinal morphology and enzyme activities of different breed lambs under the same feeding condition. Three-month-old Dorper lambs[(37.90±2.82)kg],Hu lambs[(19.20±2.94)kg]and Tan lambs[(20.67±2.39)kg]were selected as research objects. Each 14 lambs of three breeds with similar health status were selected for 15 days pre-feeding period and single pen feeding for 90 days. The results showed that the body weight and daily gain of different stages,and dry matter intake of Dorper lambs were significantly higher than those of Hu lambs and Tan lambs(P<0.05),but the differences were not significant between Hu lambs and Tan lambs(P>0.05). At the beginning of the experiment(days 1 to 3),the apparent digestibility of dry matter,neutral detergent fiber and acid detergent fiber of Dorper lambs was significantly higher than that of Hu lambs(P<0.05),and the crude protein apparent digestibility of Dorper lambs was significantly higher than that of Hu lambs and Tan lambs(P<0.05). At the end of the experiment(days 88 to 90),the crude protein apparent digestibility of Dorper lambs was significantly higher than that of Hu lambs and Tan lambs(P<0.05). The duodenal muscle layer thickness of Dorper lambs and Hu lambs was significantly higher than that of Tan lambs(P<0.05);the ileal villus height/crypt depth of Dorper lambs was significantly higher than that of Hu lambs and Tan lambs(P<0.05),and the ileal muscle layer thickness of Dorper lambs was significantly higher than that of Tan lambs(P<0.05). The amylase activity of dorper lambs and Hu lambs in jejunum was significantly higher than that of Tan lambs(P<0.05);the lipase activity of Dorper lambs in duodenum was significantly higher than that of Tan lambs(P<0.05),and the lipase activity of Dorper lambs and Tan lambs in jejunum and ileum was significantly higher than that of Tan lambs(P<0.05);the Dorper lambs had the lowest trypsin activity in duodenum and the highest trypsin activity in ileum,and the differences of them were significant compared with Hu lambs and Tan lambs(P<0.05),the trypsin activity in ileum of Hu lambs was significantly higher than that of Dorper lambs(P<0.05);in duodenum and ileum,the chymotrypsin activity of Hu lambs was significantly higher than that of Tan lambs(P<0.05),the chymotrypsin activity in duodenum of Dorper lambs was significantly lower than that of Hu lambs(P<0.05),the chymotrypsin activity in ileum of Dorper lambs was significantly higher than that of Tan lambs(P<0.05). In summary,the dry matter intake and nutrient apparent digestibility of Dorper lambs is higher,the small intestine morphology of Dorper lambs is better,and the activities of amylase and lipase in small intestine of Dorper lambs are higher than those of Hu lambs and Tan lambs,so that Dorper lambs show greater growth performance.[Chinese Journal of Animal Nutrition,2020,32(11):5322-5330]