Effects of stocking density and environmental conditions on performance, immunity, carcase characteristics, blood constitutes, and economical parameters of cobb 500 strain broiler chickens

Abstract

The effects of stocking density and environmental conditions on performance, economic profit, carcase characteristics, immunity, and blood plasma parameters of Cobb 500 strain of broiler chickens were evaluated. The 4 climate regions (mild and humid, semi-arid, alpine, hot and dry) and 4 densities (10, 15, 17 and 20 chicks/m2) were carried out as a completely randomised design with 4 × 4 factorial arrangement of treatments. The corn and soybean based diets were formulated according to the nutrition requirements guide of the Cobb 500 for starter and grower periods. The amount and the composition of the diet were the same for all experimental groups. Growth performance and feed intake were measured weekly. After the injection of sheep red blood cell at 15 and 35 days, blood samples were taken at 24 and 42 days, respectively, to study the immunity of broiler chickens. At the end of the experiment, 3 birds were slaughtered from each experimental unit for measuring the weights of carcase, abdominal fat, gastrointestinal organs (the total weight of gastrointestinal tract and caeca, and liver) and blood parameters. The interaction effects of stocking density and climate region on feed conversion ratio (in starter period), survival rate, cost, profit, cholesterol, triglyceride, high density lipoproteins (HDL), HDL/low density lipoproteins (LDL) ratio, and liver enzymes aspartate aminotranferases (AST), also known as serum glutamic oxaloacetic transaminase (SGOT), and alanine aminotranferase (ALT) were significant (p