Intestinal microbiota and broiler performance upon administration of phytase to increase phosphorus digestibility and nutrient utilization from feed

Phosphorus is an essential element in the nutrition of humans, animals, and plants. Due to the short growth period (34-42 days of age), fast growth of live bodyweight and skeleton the problem of mineral nutrition and balance (including calcium and phosphorus) is especially urgent for broiler chicks ( Gallus gallus L.). The predominant form of phosphorus in vegetable feed ingredients is phytate which is an antinutritive factor for poultry and cannot be digested. As a result the supplementation of diets for poultry with phytases, enzymes degrading the indigestible phytate complexes, has gradually become a common practice worldwide. The recent data of Russian (O.V. Trufanov, 2011; E.V. Anchikov, 2012) and foreign authors (S.W. Kim et al., 2018; C.L. Walk et al., 2019; O.O. Babatunde et al., 2019) evidenced that the supplementation of diets with reduced phosphorus content with different doses of phytase improves daily weight gains, phosphorus content in blood serum, tibial strength, and tibial contents of minerals. The efficiency of supplementation of diets for broilers (cross Cobb 500) with reduced by 0.1 % phosphorus content with two innovative new-generation phytase preparations (Feedbest-P and Berzyme-P, produced by Sibbiopharm Co., Russia) was studied; the data of pioneer research of the effects of different phytase preparations on the cecal microbial community are also presented. The trials were performed in the Center for Genetics & Selection Zagorskoye EPH (Moscow Province) in 2018. In the first trial the diets for experimental treatments were supplemented with phytase preparation 1 with activity 10,000 FTU/g (20, 40, and 60 ppm); in the second trial phytase preparation 2 was used with activity 50,000 FTU/g (6, 12, and 30 ppm). The supplementation of diets with preparation 1 increased live bodyweight in broilers at 37 days of age by 2.7; 3.0 and 3.7 % (respective to aforementioned doses) in compare to non-supplemented control treatment; feed conversion ratio (FCR) in these treatments was better by 2.9; 4.0 and 4.6 %, respectively. The respective improvements with different doses of preparation 2 were 1.3; 3.1 and 2.0 % and 1.9; 5.6 and 3.7 %. Positive effects on the digestibility of dietary nutrients, deposition of calcium and phosphorus, mineral contents in the skeleton were found with both phytase preparations. The investigation of cecal microbiota using T-RFLP (terminal restriction fragment length polymorphism) method revealed the significant increase in the pool of cellulolytic bacterial species in the phytase-fed broilers; the increases in the species of Eubacteriaceae , Clostridiaceae , Lachnospiraceae , Ruminococcaceae, and Bacteroidetes were also found. The most of the identified bacterial species in cecal population were ascribed to the phylums Firmicutes , Bacteroidetes , Actinobacteria , Proteobacteria and Fusobacteria.