Phytase and protease supplementation for laying hens in peak egg production

作者：Vieira Bruno Serpa^*; Pedrozo Vitalino Barbosa Silvana Alves; Novais Tavares Joao Marcos; Colvara Beloli Ines Gameiro; de Melo Silva Guilherme Moreira; Lima Neto Helio Rezende; Caramori Junior Joao Garcia; Correa Gerusa da Silva Salles

来源：Semina-Ciencias Agrarias, 2016, 37(6): 4285-4293.

DOI：10.5433/1679-0359.2016v37n6p4285

• Amino acid
• Egg production
• Egg quality
• Enzyme
• Nutritional restriction

The effects of enzyme combinations in diets for commercial laying hens need further clarification. The goal of this study was to determine if the type of protease used in diets supplemented with phytase affects performance, nutrient intake, egg quality or intestinal mucosa morphometry of laying hens during peak egg production. Seven hundred and eighty hens (25-week-old Hy-Line W36 hens) were assigned to a completely randomized design composed of five treatments/diets with 12 replicates of 13 birds each. The five treatments were: 1) positive control: diet formulated according to the Hy-Line nutritional recommendations, without proteases, 2) negative control A: positive control diet reduced in energy, protein and amino acids according to protease A matrix, without protease supplementation, 3) negative control B: positive control diet reduced in energy, protein and amino acids according to protease B matrix, without protease supplementation, 4) negative control A plus protease A, 5) negative control B plus protease B. There was no effect of the treatments (P > 0.05) on egg production, egg mass or feed conversion; however, the nutritional restriction imposed by the negative controls reduced egg weight (negative control A, P=0.02), albumen height (P < 0.01) and the Haugh unit (P < 0.01). Protease supplementation reduced the calculated intake of protein and amino acids compared to the positive control; nevertheless, protease A was able to maintain egg weight, albumen height and the Haugh unit at the same levels as that obtained with the positive control hens. The intestinal mucosa responded to treatment only at the jejunum (P < 0.01), but the negative controls did not modify villus height or crypt depth compared to the positive control. However, crypt depth of protease B hens was higher than that of the positive control hens. In conclusion, when included in diets supplemented with phytase, the type of protease affects performance, nutrient intake, egg quality and intestinal mucosa morphometry of laying hens during peak egg production.

• 出版日期2016