Effect of stocking density and antimicrobial inclusion on selected blood physiological variables of broilers grown to 3 kg

Abstract

Lower stocking densities may play a significant role in minimizing difficulties such as necrotic enteritis when reducing or eliminating antimicrobials (antibiotic free; ABF) in poultry diets. As the demand for poultry and associated products increases, one of the major concerns centers on the question of whether stocking density elicits adaptive responses that are characteristic of physiological stress. This study investigated the effect of stocking density and antimicrobial inclusion on selected blood physiological variables of broilers grown to 3 kg at 42 days of age. A total of 888 1-d-old Ross x Ross 708 chicks were randomly distributed into 24 pens based on stocking density treatments assignment. The treatments consisted of 4 densities (29, 33, 39, and 42 kg/m2) with six replicates. Treatments were blocked within the room to account for any variations in room conditions. Treatment assignments were randomized within each block. Used bedding was obtained from commercial farms to simulate commercial conditions. Feed and water provided ad libitum. Birds were provided a three phase-feeding program (Starter: 0-14 d, Grower: 15-28 d, and Finisher: 29-42 d). Birds and feed were weighed on 1, 14, 28, and 42 d of age for growth performance. Blood samples were collected from the brachial wing vein of 3 birds per pen on d 21 and 42, which were then analyzed immediately for whole blood physiological variables. Blood plasma samples were analyzed for T3, T4, and corticosterone. Results show there was only effect of stocking density on pCO2, which was within physiological ranges for this species. In addition, blood glucose and plasma corticosterone concentrations were not affected by stocking density, suggesting an absence of physiological stress. In conclusion, stocking densities up to 42 kg/m2 with appropriate environmental management may be suitable for both poultry integrators and contract growers to enhance broilers production efficiency without compromising the welfare of broilers grown to 3 kg at 42 days of age. USDA-ARS This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.