Effects of a semiochemical on feed conversion index and related indicators on fast-growing broilers housed during forty-two days

Consequences of stress in poultry may be assessed through a wide range of parameters. A semiochemical named mother hen uropygial secretion analogue (MHUSA) is known to decrease stress in broilers. Because stress influences their feeding behavior, this trial has been built so as to test the influence of MHUSA on feed conversion index and related indicators. Two hundred forty chicks were placed into 24 similar crates (10 chicks per crate) at 1 d of age. After 35 d, chickens under MHUSA presented similar feed conversion index compared with control. A treatment effect was observed on both heterophi:lymphocyte ratio and corticosterone (MHUSA < control; P < 0.001 for both), indicating a lower level of stress under MHUSA. Glucose, total cholesterol, and triglyceride values were comparable among treatments. Live weight and daily weight gain were greater under MHUSA (P < 0.01 for both), whereas daily food intake was comparable among treatments. It may be concluded from this study that broilers under MHUSA tend to better assimilate food, leading to a faster growth, because they cope better with stress in their surrounding.