Response of Broiler Chickens Fed Different Forms of Tanzania-type Diets with Microbial Enzymes

Abstract

A study was conducted to assess the effect of feed form and microbial enzyme supplementation on performance, endogenous enzyme activities and nutrient digestibility in broiler chickens fed Tanzania-type diets. A total of 480 day-old Ross 308 broiler chickens were allocated to a 2 (mash or pellet) × 4 (no enzyme, Axtra XB, Quantum Blue or Axtra XB + Quantum Blue) factorial arrangement, in a completely randomized design with 10 birds per replicate. Feed intake (FI), body weight gain (BWG) and feed conversion ratio (FCR) were determined at 10, 24 and 35 days of age. Visceral organ weight was measured at 10 d and 24 d, and meat parts yield was assessed at 35 d. Feed intake (FI) was highest in birds fed the pelleted diets at 24 d and 35 d, and it was increased further when enzymes were supplemented individually and in combination. Body weight gain was comparatively higher in the birds fed pelleted diets. Enzyme supplementation was found to increase BWG at 24 d and 35 d. The FCR was reduced in birds fed the pelleted diets compared to the mash-fed birds. Birds provided with a combination of Axtra XB and QB responded with lower FCR. The relative weight of gizzard plus proventriculus, pancreas and small intestine were higher in birds fed on mash; however, the effect of enzymes was only observed on the pancreas at 10 d. The relative weights of most body parts (breast, thighs and drumsticks) were significantly higher in birds fed pelleted diets with inclusion of microbial enzymes. The dry matter (DM) digestibility was neither affected by feed form nor by enzyme supplementation while the digestibility of gross energy (GE), starch, protein, and fat were higher in birds fed pelleted diets than those on mash. Addition of microbial enzymes positively influenced the digestibility of all nutrients that were assessed. Endogenous enzyme activities at 10 d were higher in birds supplied with pelleted diets, except for sucrase, which was not affected by feed form. Exogenous enzyme inclusion in diets only affected the activities of sucrase and aminopeptidase at 24 d. The results indicated that both pelleting of diets and microbial enzyme supplementation increased FI and BWG and improved FCR in broiler chickens. The activities of pancreatic and most of the jejunal enzymes were increased by feeding of pelleted feeds, resulting in better nutrient digestibility.