ABSTRACT
Background: Heat stress declines the performance through physiologic changes of the poultry
Objectives: This experiment was conducted to evaluate the effects of different levels of L-carnitine on performance, carcass characteristics and some blood parameters of broiler chickens fed with high fat diets under heat stress
Methods: Two hundred one-day-old broiler chicks [Ross 308] were used in a completely randomized design by four treatments and five replicates [pen] 10 birds in each replicate. The chickens of experimental treatments were fed with basal diet [control group] and the diets plus the different levels of 100, 200 and 300 mg/kg L-carnitine. The experimental diets were used during the finisher period [day 24 to 42 of age] and under heat stress [32 +/- 1°C as cyclic from 9.00 AM to 5.00 PM]
Results: The results showed that the chicks fed with the highest L-carnitine had the higher weight gain during the finisher period as compared to control and the lower L-carnitine fed chicks [p<0.05]. Furthermore, the feed conversion ratio of birds fed with the medium and high L-carnitine levels [100 and 300 mg] was lower than that of control birds [p<0.05]. In orthogonal contrasts, L-carnitine supplementation caused the improvement in weight gain and feed conversion ratio during both the finisher and whole experimental periods [p<0.05]. The consumption of highest L-carnitine decreased the abdominal fat as compared to control [p<0.05]. In orthogonal contrasts, L-carnitine consumption caused the higher glucose and lower abdominal fat in comparison to control [p<0.05]
Conclusions: Totally, the results of recent experiment show that consumption of 300 mg/kg L-carnitine improves the performance of broiler chickens through the increase in dietary fatty acids and energy