Annongu, A.A.Karim, O.R.Sola-Ojo, F.E.Kayode, R.M.O.Adeyemi, K.D.2023-05-092023-05-0920142012-578Xhttps://uilspace.unilorin.edu.ng/handle/20.500.12484/9924The study investigated the effect of supplementing dietary methionine on growth performance, serum biochemistry and liver histology in cockerels. A total of three hundred 1 day- old cockerel chicks were randomly assigned to diets containing 0.10, 0.25, 0.35, 0.45 or 0.55% of dietary methionine in a completely randomized design and fed for six weeks. Feed intake, weight gain, survival rate, serum cholesterol, transaminase activities and thiobarbituric acid reactive substance (TBARS) values and liver histology were determined. The result showed that feed intake and growth rate decreased with increasing level of dietary methionine although not significant (p> 0.05), while survival rate was 100% regardless of dietary treatments. Birds fed 0.10, 0.25 and 0.35% methionine had significantly higher (p< 0.05) weight gain, feed efficiency and HDL cholesterol but lower (p<0.05) LDL cholesterol and TBARS values than those fed 0.45 and 0.55% methionine. The activities of gamma glutamyl transaminase (GGT) and alanine transaminase (ALT) was significantly higher in birds fed 0.10 and 0.25 than 0.35, 0.45 and 0.55% methionine while aspartate aminotransferase (AST) activity decrease significantly (p< 0.05) with increasing levels of methionine. Normal hepatic architecture was observed in liver of birds fed 0.10 and 0.25% methionine while those fed higher levels had distorted hepatic architecture, the severity of which increased with increasing levels of methionine. Thus, inclusion of supplemented dietary methionine above 0.25% is likely to create health hazards in poultry in a tropical environment like Nigeria.enMethionine, cockerels, performance, serum cholesterol, liver histology.Article