Effect of Graded Levels of Vitamin D3 (Cholecalciferol) on the Performance, Carcass and Organ Weights of Broilers Chickens

A 56 - day study to determine the effects of graded levels of cholecalciferol (Vitamin D3) on performance, carcass and organ weights of broiler chickens was conducted. Two hundred and forty day old Marshall Broiler chickens were weighed and randomly placed into twelve pens in a completely randomized design. There were four treatment groups and three replicates for each treatment. Sixty birds were allotted to each treatment group. Treatment A contained 0% of vitamin D3 (control) in the broiler vitamin/ trace mineral premix used to formulate the experimental broiler starter and finisher diets. Treatments B, C and D contained 40%, 80% and 100% inclusion of vitamin D3 respectively. The birds were weighed weekly to determine weight gains. Daily feed consumption was taken and feed conversion ratio determined weekly. At the end of the 56-day performance study, six birds per treatment of two per replicate were slaughtered, defeathered and eviscerated to determine dressed carcass and organ weights (liver, gall bladder, gizzard, spleen and heart). Body weight gains and feed conversion ratio were not significantly (P > 0.05) different. However there was a significant (P < 0.05) difference in the weight of the gizzards at the 80% and 100% inclusion levels. Birds fed 100% inclusion levels of vitamin D3 in their diet had the highest carcass weight. It was concluded that the inclusion of 100% vitamin D3 in the broiler vitamin/ trace mineral premix as formulated and recommended by the manufacturers for broiler rations was adequate.