The effect of dietary xylanase on energy, amino acid and mineral metabolism and egg production and quality in laying hens

Vasil Pirgozliev (1) , Tom Acamovic (2) , Mike Bedford (3)

1 SAC
2 ASRC
3 R&D

1. The aim of the present study was to examine the effect of dietary xylanase on the availability of nutrients for laying hens when fed on wheat-rye-soy-based diets. The basal diet was formulated to contain 11.03 MJ/kg apparent metabolisable energy (AME) and the experimental diets were formulated by supplementing the basal diet with four different activities of xylanase (400, 800, 1200 and 1600 XU (xylanase units), respectively). 2. The AME and nitrogen metabolisability coefficient of xylanase supplemented diets was 1.2% and 7.1%, respectively, higher (P<0.05) than the control diet. 3. Supplementary xylanase improved (P<0.05) the coefficients of metabolisability of indispensable, dispensable and total amino acids by 8.2, 6.9 and 7.8%, respectively, and led to a linear (P<0.05) response of total amino acid metabolisability coefficient to xylanase. There was a range of effects within the indispensable amino acids with xylanase supplementation (1600 XU) improving (P<0.05) the metabolisability of threonine by 4.9%, but having no have effect (P>0.05) on lysine. The response of total amino acid retention to added xylanase was a quadratic function (P=0.051), and suggests that 800 XU is the optimum supplementary dosage. 4. Supplementary xylanase improved (P<0.05) sulphur metabolisability in a linear fashion to a maximum of 2.3% higher than that of the control diet. In terms of daily retention most of the minerals responded in a quadratic manner to dietary xylanase, as the suggested optimal supplementary level was between 800 and 1200 XU. 5. The yolk colour of the birds fed 1200 and 1600 XU was 0.33 and 0.28 units (Roche score), i.e. 4.1 and 3.5% respectively, darker (P<0.001), than the yolk of the birds fed the control diet. 6. Birds fed xylanase had higher weight gain (P<0.05) than those fed the unsupplemented diet. Feed intake, the number of eggs per hen day, dirty and cracked eggs and feed conversion ratio for egg production (FCR) were not affected (P>0.05) by xylanase. These data suggest that use of a xylanase may improve the metabolisability of many nutrients but that such effects may not always benefit production parameters.

Mots clés: Life Sciences

Vasil Pirgozliev, Tom Acamovic, Mike Bedford. The effect of dietary xylanase on energy, amino acid and mineral metabolism and egg production and quality in laying hens. British Poultry Science, 2010, 51 (05), pp.639-647. ⟨10.1080/00071668.2010.514325⟩. ⟨hal-00638522⟩