Effect On Intestinal Development By The Different Feed Forms And ?-carotene In Lay Hens In The Reserve Period

?-carotene is a widespread chromophyte in the nature,which is an important source of vitamin A.A series of studies has demonstrated its antioxidant,which can enhance animal reproductive performance and the immune function.In this work,the byproduct of Carrot(?-carotene)was made into two types of feed(pellet and powder).Then Hyline Brown hens were fed with them.After experimental treatments,we observed the following indexes: immune function,blood,antioxidant function and intestinal mucosal immune function.This work demonstrates ?-carotene's functions,which can prompt intestinal development.These findings provide a theoretical basis for further applying ?-carotene as feed additive.In the current study,240 Hyline Brown hens(21 day old)were selected and randomly divided into 4 groups: the basic diet pellet group,basal diet powder group,carrot residue granule group and Carrot Pomace powder test group,each of which included 6 replicates of 10 hens per replicate.The experimental period lasted 5 weeks(from 3 weeks to 8 weeks).The results are as follow:In the growth performance: the body weight of pellet group was significantly higher than that of the powder group(P<0.05).In addition,the body weight of pellet group(containing ?-carotene)was also significantly higher than that of the powder group.The differences for other indexes are not significant.These results indicate that the feed form may affect the body weight.In the aspect of indexes of blood?immunity and antioxidant: the content of MDA in serum was significantly higher than that of powder group(P<0.05)at 8 weeks old.The contents of IgA and MDA in serum containing ?-carotene group were significantly higher than those in the non-containing ?-carotene group.But there was no significant difference in serum IgG and IgM(P>0.05),and there was no significant difference in serum GSH-PX,T-SOD and T-AOC(P>0.05).In the aspects of intestinal development and intestinal length: Compared with the control group,the pellet and powder added ?-carotene were significantly higher than basal diet control group(P<0.05)in the duodenum villus height,villus height of jejunum;the expression and distribution of IgA-positive cell were significantly(P<0.05),however,there were no significant differences in the villus height,crypt depth and villus gland ratio(P>0.05).Taken together,granular material is better than that of powder in the reserve period for Hyline brown layers in terms of intestinal development;?-carotene can improve the intestines development,enhance intestinal immune ability,promote and so on.Our current study can provide experimental basis and data for the production practice of chuckling.