Effect of vitamin C and betaine supplementation on the performance of broilers exposed to heat stress

This experiment was conducted to evaluate the effects of vitamin C and betaine on broiler performance that exposed to heat stress during 42 days of age. For this purpose، 3 basal diets were formulated according to Ross 308 recommendation (2007) Then vitamin C and betaine were added to basal diets and 4 dietary treatments were obtained as follow: 1-Basal diet 2- Basal diet + 0. 05% vitamin C 3- Basal diet + 0. 15% betaine 4- Basal diet + 0. 05% vitamin C + 0. 15% betaine. During 42 days of experiment، each diet was fed ad libitum by 4 replicate groups that each of replicate was contain 10 mixed sex Ross strain broilers. The birds were exposed daily to heat stress for 7 hours. In this experiment average of feed intake، weight gain، feed conversion ratio were evaluated in each phase of feeding and total period. Mortality percentage، cost of feed consumption in return for production of 1 kg body weight and production index were studied in total period. At the end of experiment، 2 birds were slaughtered from each replication and carcass percent of them were calculated and carcass components and other parameters (thighs، breast، back and neck، wings، abdominal fat، heart، spleen، liver and gizzard) were weighted. The results of experiment were showed that average feed intake had no significant effect between treatments in starter، grower، finisher and total periods. The effect of weight gain was significant in grower and total periods. Effect of feed conversion ratio was significant between treatments in grower، finisher and total period. Effect of mortality percentage was significant in total period. The comparison average production index was significant in total period. Cost of feed consumption for 1 kg body weight was significant between different treatments in total period. The effect of breast percentage (in male) and gizzard percentage (in female) were significant. Based on obtained results، vitamin C and betaine are suitable for using in broiler diets exposed to heat stress.