Discipline: Veterinary Medicine
A preliminary study was conducted to assess the potential of cysteamine (CT) to improve broiler production by determining the performance carcass characteristics and histology of the intestinal tract of broilers fed diets with different dietary crude protein (CP) levels with or without cysteamine supplement. A total of 540 broiler chicks were randomly assigned to six dietary treatments in a 3 x 2 factorial arrangement in a completely randomized design (CRD). Main factors were three dietary protein levels and the inclusion of cysteamine (CT). The dietary treatments were as follows: T1-basal diet without CT: T2-basal diet with CT; T3-increased CP diet without CT; T4-increased CP diet with CT: T5-reduced CP diet without CT; T6-reduced CP diet with CT. Results showed no significant interaction effects between dietary protein levels and cysteamine supplementation on body weight and weight. gain, feed efficiency and other parameters measured. As a single factor, inclusion of CT in the broiler diet significantly improved weight gain at 28 days of age and overall feed efficiency. Birds fed diets with increased CP level with or without CT were significantly more feed efficient that those fed the reduced CP-diets. Mortality rate, dressing percentage and lean fat ratio of birds in the different treatment combinations were not significantly different. Histologically, regardless of dietary CP level, birds fed diets with CT had fewer but longer villi , more intestinal glands and goblet cells in the epithelium of the small and large intestines compared to those fed diets without CT. These findings indicate that the positive effects of CT on the growth of broilers could partly be attributed to a more efficient digestion and absorption of nutrients in the intestinal tract. Results of this preliminary study showed that CT offers considerable potential to improve broiler production. Further studies, however, must be conducted using different CT levels and time of administration.