The effects of feed additives based on the hydrolysates of keratin- And collagen-containing waste materials on the intestinal microbiota and productivity parameters in broiler chicks (Gallus gallus L.)

Abstract

The use of new animal-derived protein ingredients in commercial diets for poultry as a substitute for the expensive fishmeal is an urgent direction of the nutritional research. At present a range of new additives is designed based on the wastes of poultry slaughter and processing. In this paper, we first report the results of comparative analysis of the bacterial community in blind processes of the intestines of broiler chickens fed with dietary protein-rich additives derived from keratin- and collagen-containing waste products after short-term high-temperature enzymatic hydrolysis in a thin layer. These findings show possibility of using new feed additives to increase the productivity and quality of broiler meat. Our study was aimed at the evaluation of the effects of the feed additives based on keratin- and collagen-containing wastes on the intestinal microbiota counts and composition in conjunction with productive performance of broiler chicks. The chicks (Gallus gallus L.) of Ross 308 cross were reared at the Vivarium of All-Russian Research and Technological Institute of Poultry (Moscow Province) on the floor until 38 or 49 days of age. Control Treatment (Trt) 1 was fed standard diet with fishmeal as the main protein source. In the diet for Trt 2 the fishmeal was substituted by a hydrolysate of keratin-containing wastes (poultry feathers); in Trt 3 by a hydrolysate of collagen-containing wastes of poultry deboning; in Trt 4 by a mixture of these additives with additional supplementation with probiotic Bacell-M (containing Bacillus subtilis, Lactobacillus paracasei, Enterococcus faecium). The counts and composition of cecal microbiota in broilers were determined using Terminal Restriction Fragment Length Polymorphism (T-RFLP) technique. The live weight at 38 and 49 days of age (individual weighing), average daily weight gain, livestock safety, feed costs per 1 kg of live weight, grade and weight of gutted carcasses, meat yield of carcasses and meat qualities, digestibility and use nutrient feed were recorded. The protein additives based on the hydrolysates of poultry wastes do not compromise the composition of cecal microbiota in broilers, and the obligate species were abundant with all diets studied. Cellulolytic Clostridia class (phylum Firmicutes) including families Ruminococcaceae, Eubacteriaceae, Lachnospiraceae, Clostridiaceae etc. dominated in the cecal microbial communities. The additives beneficially affected the productive performance in broilers. The best productivity parameters were in broilers fed diets with the hydrolysate of keratin-containing material (Trt 2) and a mixture of the hydrolysates of keratin- and collagen-containing wastes with the probiotic (Trt 4). Average live bodyweight at 38 and 49 days of age in Trt 2 was significantly higher, by 9.2 % (p < 0.01) and 10.1 % (p < 0.001), respectively, as compared to control Trt 1. Mortality level in Trt 2 was 0 % while feed conversion ratio (FCR) at 38 and 49 days of age was 6.32 and 7.28 % better compared to control. Average live bodyweight in Trt 4 at 38 days of age was 5.3 % higher, and FCR was 2.87 % better compared to control; at 49 days of age these parameters were better in compare to control by 4.96 and 4.37 %, respectively, while mortality in Trt 4 during 38 and 49 days of rearing was 0 %.