Abstract:
22A Influence of microbial phytase and xylanase on broiler performance Y.B. Wu, V. Ravindran and W.H. Hendriks Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand V.Ravindran@massey.ac.nz The influence of phytase produced by solidstate fermentation (Allzyme SSF�) and xylanase (Allzyme PT) on the performance of male broilers and the apparent metabolizable energy (AME) of their wheat soy diets containing adequate phosphorus was investigated in a 3 week trial. Experimental diets were additions of xylanase (1000 XU/kg) and phytase (500 PU/kg) singly or in combination to the control diet based on wheat (67.3%) and soybean meal and containing 0.45% nonphytate P. Each diet was fed to 5 pens of 8 birds. Toe samples were obtained on day 21; AME was determined from total collection of excreta during week 3. Supplemental phytase improved weight gains and feed efficiency by 17.5 and 2.9% respectively, and xylanase by 16.5 and 4.9% (P<0.05; Table 1). In combination, compared with the basal diet, they improved weight gains by 19.8% (P<0.05) and lowered feed/gain by 5.4% (P<0.05). The improvement in the performance of birds given xylanase was expected and is consistent with previous reports (Annison and Choct 1991; Bedford and Classen 1992). That phytase was as effective as exogenous xylanase, especially in diets containing adequate P, was unexpected. This may be because the phytase used in the present study contained relatively high levels of glucanase, xylanase and protease, and that may also explain why phytase and xylanase together had no further beneficial effects on broiler performance. Treatments had no effect on toe ash contents because dietary P in the present study was adequate (0.45%). It appears that the performance responses from supplemental phytase are not related to a P effect, but are likely to reflect the enzyme effects on other nutrients. Improvements in AME from individual additions of xylanase and phytase were not significant (P>0.05), but were significant with the combined addition (P<0.05) which confirms a previous finding (Ravindran et al. 1999). Annison, G. and Choct, M. (1991). Antinutritive activities of cereal nonstarch polysaccharides in broiler diets and strategies minimising their effects. Worlds Poultry Science Journal 47, 232242. Bedford, M.R. and Classen, H.L. (1992). Reduction of intestinal viscosity through manipulation of dietary rye and pentosanase concentrations is effected through changes in the carbohydrate composition of the intestinal aqueous phase and results in improved rates and food conversion efficiency of broiler chicks. Journal of Nutrition 122, 137142. Ravindran, V., Selle, P.H. and Bryden, W.L. (1999). Effects of phytase supplementation, individually and in combination, with glycanase, on the nutritive value of wheat and barley. Poultry Science 78, 15881595. 1 Table 1 Influence of enzyme treatments on broiler performance (1_21 days) . Treatment Gain (g/bird) 726a 84 7b 1b (+16.5) 2 Feed/gain (g/g) 1.516 1.442 bc a Toe ash (% dry matter) 12.28 11.94 12.08 12.20 0.221 AME (MJ/kg dry matter) 14.19 14.43 14.39 ab ab b a Basal Basal + xylanase Basal + phytase Basal + xylanase + phytase Pooled SEM a,b 1 2 (_4.9) (+1.7) (+1.4) 853b (+17.5) 87 (+19.8) 1.472b (_2.9) 1.434 (_5.4) 0.0105 c 14.68 (+3.5) 0.116 24.8 Means in a column with different superscripts differ (P<0.05) Values are means of five replicates Values in parentheses refer to percentage changes over the basal diet from the addition of enzyme Recent Advances in Animal Nutrition in Australia, Volume 14 (2003)