Effects Of Dietary Vitamin A Levels On Growth Performance, Immunology, Antioxidant Index And Vitanmin A Tissue Retention Of Broilers

The objective of this study was to evaluate the effects of dietary vitamin A level on productive performance,immune function,antioxidant index of broilers and tissue deposition of vitamin A. It can provide scientific basic for vitamin A level in practical diet of broilers.1. This study was designed to research the effects of adding different levels of vitamin A on productive performance,immune function and antioxidant index of broilers. 960 1-day-old male Arbor Acres broilers were assigned to 8 treatment groups, each group set up six replicates(20 chicken per replicate), respectively. The broilers received the same basal diet supplemented with vitamin A 0 (control), 750, 1 500, 3 000, 6 000, 12 000, 24 000 and 48 000 IU/kg, the feeding trial lasted for 42 days. The results showed that:①Throughout the trial period, the body weight gain of each added vitamin A group was higher than control group(P<0.05), but there is no significant between added vitamin A groups (P>0.05). Compared with the control group, 3 000 IU/kg added vitamin A can significantly reduce the feed conversion ratio (P<0.05), the rest of the group increased the trend of reducing the ratio of feed (P>0.05).②The effect of dietary vitamin A supplementation on index of bursa of fabricius was significant (P<0.05), the level of 6 000 IU/kg is best for development of broilers immune organs.③Vitamin A supplementation levels had significant effects on GSH-Px enzyme activity and content of MDA of broilers serum (P<0.05), the level between 6 000 IU/kg and 12 000 IU/kg can improve the antioxidant capacity of broilers.2. This study was designed to research the effects of adding different levels of vitamin A on vitamin A Deposition of broilers. 960 1-day-old male Arbor Acres broilers were assigned to 8 treatment groups, each group set up six replicates(20 chicken per replicate), respectively. The broilers received the same basal diet supplemented with vitamin A 0 (control), 750, 1 500, 3 000, 6 000, 12 000, 24 000 and 48 000 IU/kg, the feeding trial lasted for 42 days. The results showed that: 21 days and 42 days old broilers liver vitamin A content and addition of dietary vitamin A showed a linear regression relationship (P<0.05, R2 was 0.997 and 0.998). Vitamin A content of serum vitamin A levels between the diet had significant logarithmic correlation (P<0.05), regression equations were y= 0.6587Ln (x) +0.1165 (R2= 0.9518) and y= 0.986Ln (x) +0.0371 (R2 = 0.9705) (x is the amount of dietary vitamin A added.)3. This study was designed to research the effects of adding different levels of vitamin A (0,3 000,6 000,9 000,12 000 IU/kg) on lysozyme and immunoglobulin levels of broilers serum. The results showed that:①Vitamin A supplemental levels had no significant effects on immune organ indices(spleen index and index of bursa of Fabricius) of 21days and 35 days old broilers (P>0.05);②As the dietary vitamin A level increased, the serum lysozyme of 21days and 35 days old broilers were significantly increased (P<0.05);③As the dietary vitamin A level increased, the serum IgA level increased significantly (P<0.05), and reached the highest when the vitamin A supplemental level reached 6 000 IU/kg. In conclusion, diets supplemented with 6 000 IU/kg vitamin A, can significantly improve the immune function of broilers.