Evaluating the effects of microencapsulated blends of phytobiotics in the diet of broiler chickens

Abstract Text: This study was conducted to determine the effects of supplementing diets with microencapsulated blends of phytogenics (MPH) on growth performance, carcass characteristics, fecal microbiota, blood constituents, and excreta noxious gas emission in broiler chickens. A total of 768 d-old Ross 308 (as hatched) broiler chicks with an average initial body weight of 40 ± 0.9 g were used in a 35-d growth assay. There were four treatments and each treatment consisted of 12 replications with 16 birds/ pen, with food and water consumed ad libitum. Treatments were designed as a corn-soybean-meal-based diet with none, 0.025 and 0.05, and 0.075% of MPH. Data were analyzed as a completely randomized design via ANOVA using the GLM procedure described by SAS. Polynomial regression was used to describe the shape of the response to increasing concentration of microencapsulated blends of phytobiotics in the diet. Results indicated improvement in body weight gain (BWG) and feed conversion ratio (FCR) (linear effect, P< 0.05). Increasing concentration of MPH in the diet from none to 0.075% increased (P< 0.05) BWG at d 1 to 7, 7 to 21, and 1 to 35, and decreased FCR at d 7 to 21 and 1 to 35 (P< 0.05 ). Supplementing the diets with various levels of MPH had no effect on pH value of the breast meat, meat color and relative organ weights, but drip loss percentage decreased linearly (P= 0.01) on d 7 by increasing the concentration of MPH from none to 0.075%. Fecal microbiota assay indicated that supplementing the diets with 0 to 0.075% of MPH increased the fecal Lactobacillus count linearly (P= 0.002), but the E. coli count was not affected. Results demonstrated that whole blood cell counts, lymphocyte percentage and IgG concentration were not influenced, but concentration of haptoglobin dropped linearly (P= 0.001) by increasing dietary concentration of MPH. Thus, it was concluded that inclusion of MPH improved growth performance and positively manipulated fecal Lactobacillus population with no negative effect in broilers.

Keywords: Broiler, carcass characteristics, nutrient digestibility