Associação Enzimática em Dietas de Poedeiras Criadas em Sistema Free Range.

Abstract

The free range system is an alternative to conventional cage systems. The use of enzymes as feed additives for commercial laying hens may increase the digestibility of nutrients from dietary ingredients. In this study, the nutritional contributions of phytase and xylanase enzymes in egg yield and quality are addressed, considering the new free range production trends. An experiment was carried out with 800 laying hens of the Isa Brown line from 24 to 30 weeks of age, distributed in a randomized complete block design in a 2 x 2 factorial scheme (2 associations of enzymes (phytase and xylanase) x 2 nutritional matrices, first conventional market and the second overvalued), totaling four treatments with five replicates and 40 birds per experimental unit. The blocks were established according to the weight of the birds. The treatments were: T1: phytase (450 FTU / kg) + xylanase (12000 BXU / kg) + Matrix I (EMA, Kcal / kg: 100; Ca%: 0.16; Pd%: 0.15; Na% 0.03, Lys. Dig%: 0.02); T2: phytase (1500 FTU / kg) + Matrix I (EMA, Kcal / kg: 100; Ca%: 0.16; Pd%: 0.15; Na%: 0.03;Lys Dig%: 0.02); T3: phytase (450 FTU / kg) + xylanase (12000 BXU / kg) + Matrix II (EMA, Kcal / kg: 120, Ca%: 0.22, Pd%: 0.20, Na%: 0.04; Lys. Dig%: 0.05); T4: Fitase 1500 FTU / kg) + Matrix II (EMA, Kcal / kg: 120, Ca%: 0.22, Pd%: 0.20, Na%: 0.04; Lys Dig%: 0.05). The variables of productive performance, external and internal quality of eggs were analyzed. The association of phytase or phytase + xylanase, regardless of the matrix used, was able to meet the requirements of the animals and maintain productive performance. However, the combination of phytase (450 FTU / kg) + xylanase (12000 BXU / kg) and the adoption of matrix I (EMA, Kcal / kg: 100, Ca%: 0.16, Pd%: 0.15, Na %: 0.03; Lys. Dig%: 0.02) was more efficient to maintain the egg quality of laying hens raised in the free range system