| The source of protein in the diet can affect the animal's production performance and digestive enzyme secretion.This study investigated whether adding cotton meal and rapeseed meal to laying hen diets would affect the secretion of digestive enzymes and animal performance.In the experiment,a corn-soybean meal diet was used as a control group.Under the conditions of isoenergetic,isoprotein,and digestible amino acids,cotton meal and rapeseed meal protein were used instead of 10% soybean meal protein to feed 8-week-old laying hens to evaluate their production performance and digestive enzyme secretion.Three hundred seventy eight 8-week-old hens were randomly divided into 3 treatments,with 7 replicate pens of 18 laying hens.The 3 treatment groups were: corn-soybean diets(SBM),corn-cottonseed meal-soybean diets(CSM),corn-rapeseed meal-soybean diets(RCM).By using cottonseed meal and rapeseed meal instead of soybean protein in laying hens,the effects of mixed meal on production performance and digestive enzyme secretion in layering hens were studied.The results showed that compared with the control group,the body weight of the chickens in the cottonseed meal group showed a downward trend in the 13 th week(P = 0.0662).There was no significant difference in the activities of amylase,lipase,trypsin,and chymotrypsin in the contents of duodenum,jejunum,and ileum between the three groups(P>0.05).Compared with the control group and rapeseed meal group,the lipase activity in the pancreas of the cottonseed meal was significantly increased(P<0.05).There was no significant difference in the activity of pancreatic amylase,trypsin and chymotrypsin among the three treatment groups(P>0.05).At the 13 th week of breeding layer,different dietary protein sources had no significant effect on the intestinal morphology of the duodenum,jejunum,and ileum of the hens(P>0.05).At 15 weeks of age,compared with the control group,the ileum organ index of the cottonseed meal group and rapeseed meal group were significantly reduced(P<0.05),and the amylase activity of the test chickens in the cottonseed meal group increased with a significant difference(P<0.05).Compared with cottonseed meal group,ileum amylase activity in rapeseed meal group was significantly reduced(P<0.05).Compared with the control group,the duodenum lipase activity of the cottonseed meal group and rapeseed meal treatment group were significantly increased(P<0.05),the chymotrypsin activity of the test chicken in the rapeseed meal group was increased significantly(P<0.05)and the chymotrypsin activity in the ileal contents of the cottonseed meal was significantly increased(P<0.05).The amylase activity in the pancreas of the rapeseed meal was significantly reduced under the feeding states(P<0.05).Compared to the fasting states of the pancreatic tissue,the amylase activity of the pancreatic tissue was significantly reduced under the feeding states(P<0.05).Different dietary protein sources did not significantly affect the intestinal morphology of the duodenum,jejunum,and ileum of 15-week-old chickens(P>0.05).At week 18,compared with the control group,the pancreas organ index of the cottonseed meal group was significantly increased(P<0.05).Compared with the control group and the rapeseed meal group,the activities of amylase,lipase,trypsin,and chymotrypsin in the jejunum of the cottonseed meal increased significantly(P<0.05).Compared with the control group,the amylase activity of the pancreas in the group supplemented with cotton meal and rapeseed meal protein was significantly reduced in the fasting states(P<0.05).Compared with the control group and the rapeseed meal group under feeding conditions,the lipase activity in the pancreas of the cottonseed meal was significantly increased(P<0.05).Compared with the fasting states,the amylase activity,trypsin activity and chymotrypsin activity of pancreatic tissues were significantly reduced with the feeding states(P<0.05).The addition of cottonseed meal and rapeseed meal in place of 10% soybean meal protein had no significant effect on the villi height,crypt depth,and vill / crypt ratio of the duodenum,jejunum,and ileum of broiler chickens(P>0.05).The results showed that 10% soybean meal protein was replaced by cottonseed meal and rapeseed meal in the diet,which had no significant effect on the performance,organ index,digestive tract development and digestive enzyme activities of laying hens. |
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