INCREASING THE ACTIVITY OF ANTIOXIDANT SYSTEM IN BROILER CHICKS DURING SUMMER SEASON 2-EFFECT OF PREBIOTIC SUPPLEMENTATION ON GROWTH PERFORMANCE, MEAT, QUALITY AND OXIDANTIVE STATUS OF BLOOD

Ahis study was conducted during summer season to investigate the effect of adding mannan-oligo-saccharide (MOS) to the diet or drinking water on the growth performance and some biological values like, total lipids, triglycrides cholesterol and some antioxidants enzymes in plasma and meat of broiler chickens from 1 day till 40 days of age. Two hundred eighty-1-d-old broiler chicks were randomly divided into seven treatment groups with four replicates of 10 birds each. Chicks were fed on corn-soybean meal basal diets during starting (1-10d), growing (11-24d) and Finishing (25-40d) periods. All birds were kept under similar management conditions. The experimental treatment groups were as follows: 1- A control group without MOS, group2 received a diet supplemented with MOS 1g/kg and groups 3 to 7 received the basal diet and had MOS in drinking water at the rate of (0.40 g/L, 0.45 g/L, 0.55 g/L and 0.60 g/L).The results showed that the highest (P < 0.001) body weight and body weight gain was recorded for the group fed on 1gm MOS/kg diet and also the other group treated with MOS in drinking water recorded significant (P < 0.001) increased in BW & BWG compared with control. Similar trend was nearly obtained for feed conversion ratio (FCR).No significant differences have been recorded in carcass and part yield or abdominal fat in treated groups. Also there were no significant differences in total lipid or cholesterol HDL and LDL. The addition of the MOS led to increased MDA in treatments 1gm/kg diet and 0.60 gm/L (high level of MOS) and reduction in the rest of treatments compared with control. Also MOS increased significantly (P < 0.001) activity of GPx in treatments (0.40, 0.50,0.55 and 0.60g MOS/L) than the other treatments. Also GSR increased significantly (P < 0.005) in the almost treatments supplemented with MOS. There were no significant effects of MOS on cholesterol, HDL, LDL and T.G on meat lipid of birds in any treatment. There was a significant (P < 0.001) increased pH meat in all treatments supplemented with MOS, also MDA in the meat showed significant increased (P <0.001) in treatment supplemented with high level of MOS (0.60 gm/L) in drinking water. It could be concluded that treated broilers with high level of MOS reduced the negative effects of heat stress and it hence improvements the growth performance.