Effects Of β-carotene On The Growth And Development Of Egg Chicks And Their Specific Cleavage Enzyme Gene Expression

Egg chicks in the brooding period shows the low immune function,easily infected with various diseases due to immature body development.β-carotene is an important source of vitamin A,which possesses antioxidant,enhances immune function and other important physiological functions.729 one-day-old female chicken were randomly divided into 3 groups.Each group set three repeating group.The control group was with the basal diet,the other two groups were fed with the basal diets added with 60mg/kg β-carotene and 2% carrot dross.After 6 weeks,the effects of β-carotene on the growth performance,blood immunity,biochemical indexes and intestinal histomorphology of chicks were observed and the relative expression of β-carotene specific oxidase gene was determined.The results showed that after 2,3 and 5 weeks of feeding,the weight of egg chicks in β-carotene group was significantly higher than that in control group(P<0.05),after 3 and 4 weeks,the length of tibia in the β-carotene group was significantly higher than that of control group(P<0.05),the average daily gain of chickens in β-carotene group was significantly higher than of control group at 3 weeks(P <0.05),the serum levels of IgA in the 3-week-old β-carotene group and the carrot dross group were significantly higher than those of control group(P<0.05),the serum IgA levels in the 6-week-old β-carotene group were significantly higher than those in the control group and the carrot dross group(P<0.05),the duodenum and jejunum villus height in the β-carotene group and the carrot dross group were significantly higher than those in the control group(P<0.05),compared with the control group,the height of ileal villus in chickens of β-carotene group was significantly different(P<0.05).The relative expression levels of BCMO1 and BCDO2 in the liver and duodenum were significantly higher than those in the control group(P<0.05).In summary,in the brooding stage,β-carotene can improve the growth performance of egg chicks,enhance the expression of IgA in the blood and promote normal intestinal development.β-carotene can promote the BCMO1,BCDO2 gene expression,which indicates that there is a certain relationship between the effect of β-carotene on the relative expression of oxidase gene,and build the foundation for the absorption and utilization of β-carotene in egg chicks.At the same time,the addition of carrots dross in the brooding early also has a very good effect,which is also a potential for the use of carrot slag feed additives laid the theoretical basis.