Effect of Season and Dietary Protein Level on Blood Constituents of Three Exotic Broiler Strains in Sudan

Abstract

This study was conducted to investigate the effect of the season (the summer versus the winter) and dietary protein level (high versus low), using three broiler strains (Ross, Cobb and Hubbard), on some physiological parameters. Three hundred and sixty, one-day-old unsexed, broiler chicks were used during the summer and winter seasons, 120 from each of Ross strain, Cobb strain and Hubbard strain. Two experiments were executed in a complete randomize design (factorial arrangement 3x 2x 2). Each strain was divided into two groups, with six replicates (10 chicks per each replicate). Group A of each strain was fed on a starter diet containing 23% crude protein for the first four weeks of age, replaced by a finisher diet containing 21% crude protein. Group B was fed on a starter diet containing 21% crude protein replaced by a finisher diet containing 19% crude protein. The results revealed that there was a significant (P= 0.05) broiler strain X season interaction for all parameters under investigation. In both Cobb and Hubbard strains, the packed cell volume (PCV) decreased significantly (P<0.05) during the summer season, whereas, it was significantly (P= 0.05) increased in Ross strain during the same season. The haemoglobin concentration decreased significantly (P= 0.05) in Cobb strain during the summer, while it was not significantly affected by the season in both Ross and Hubbard strains. The total red blood cells count was not significantly affect by the season in the three broiler strains. The heterophil/ lymphocyte ratio (H/L ratio) increased significantly (P= 0.05) during the summer in both Hubbard and Ross strains, but it was not significantly affected by the season in Cobb strain. Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark. The mean cell volume (MCV) increased significantly (P= 0.05) during the summer in Ross strain, but it was not significantly affected by the season in Cobb and Hubbard strains. The mean cell haemoglobin (MCH) decreased significantly (P<0.05) during the summer in both Ross and Cobb strains, whereas, in Hubbard strain it was not significantly affected by season. The mean cell haemoglobin concentration (MCHC) decreased significantly (P= 0.05) during the summer in all broiler strains. Serum glucose concentration decreased significantly (P= 0.05) during the summer in Ross and Hubbard strains, while it was not affected by the season in Cobb strain. The serum albumin concentration decreased significantly (P= 0.05) during the summer in Ross strain, but it was not significantly affected by the season in Cobb and Hubbard strains. Serum sodium (Na), potassium (K) and phosphorus (P) concentrations were decreased significantly (P= 0.05) during the summer in all strains. The serum calcium (Ca) concentration decreased significantly (P= 0.05) during the summer in Cobb strain. It was not significantly affected by the season in Ross and Hubbard strains. Although there was significant (P= 0.05) broiler strain X protein level interaction effect on PCV, H/L ratio, MCV, MCHC, serum glucose, serum albumin, serum Na, K, Ca and serum P the dietary protein level appeared to be has no significant effect on any of physiological parameters under