Effect of a microbial phytase produced by solid state fermentation on the performance and nutrient utilisation by broilers fed wheat soy canola diets.

Abstract

28A Effect of a microbial phytase produced by solid state fermentation on the performance and nutrient utilisation by broilers fed wheat_soy_canola diets Y.B. Wu1, V. Ravindran1, D.V. Thomas1, B.J. Camden1, P.C.H. Morel1, W.H. Hendriks1 and J. Pierce2 1 2 Monogastric Research Centre, Massey University, Palmerston Nor th, New Zealand Alltech Inc., Nicholasville, Kentucky, USA v.ravindran@massey.ac.nz The effects of a phytase (Alltech Inc., Nicholasville, KY) produced by solid_state fermentation, which contains several side_enzyme activities in addition to phytase, on the performance and nutrient utilisation by male and female broilers fed a wheat_soy_canola diet was investigated in a 6_week trial. Dietary treatments were: (1), negative control with 0.30 and 0.20% nonphytate phosphorus during weeks 1_3 and 4_6, respectively; (2, 3, and 4), treatment 1 plus 0.06, 0.12, or 0.18% nonphytate phosphorus as monocalcium phosphate; and (5, 6, 7, and 8), treatment 1 plus 500, 1000, 1500, or 2000 PU phytase/kg diet. Within sex, each diet was fed to five pens of eight birds each. Total excreta were collected during week 3 for the determination of apparent metabolisable energy (AME). Ileal digesta and toe samples were obtained on day 42. Apparent ileal phytate degradation (AIPD) and apparent ileal nitrogen digestibility (AIND) were calculated from the concentrations of TiO2 marker in the diet and ileal digesta. In general, the treatment effects on parameters tested were similar in both sexes, but only the data for males are presented (Table 1). Weight gains, feed/gain and toe ash contents were increased as the inorganic P or phytase was added to the low_P diet, the magnitude of the increases being greatest for the first addition of P or phytase and then tended to plateau with further additions. Gain and toe ash content of birds fed the low_P diet (5) with 500 PU phytase/ kg were similar to those of birds fed the adequate_P diet (4), but the feed efficiency was better. Ileal phytate degradation data provided direct evidence on the efficacy of phytase in hydrolysing the phytic acid. Improvements in broiler performance with phytase addition were also associated with linear increases in AIND and AME. The overall responses observed may in part reflect the side_enzyme activities present and suggest that multiple enzyme products may be a competitive strategy to improve the nutritive value of wheat_based diets. Table 1 Performance (1_42 days) and nutrient utilisation in male broilers fed wheat_based diets containing var ying levels of dietary phosphorus (P) and microbial phytase (MP). Diet Gain (g/bird) 2452 2586 2600 2627 2640 2684 2701 2781 35 * *** Feed/gain (g/g) 1.911 1.873 1.880 1.832 1.775 1.754 1.730 1.740 0.02 * *** Toe ash (% DM) 9.7 10.6 10.7 10.7 10.7 10.9 10.8 11.0 0.21 * * AIPD AIND AME1 1 2 3 4 5 6 7 8 SEM P effect MP effect 1 0.32 0.27 0.31 0.30 0.57 0.64 0.70 0.79 0.04 NS ** 0.81 0.79 0.79 0.78 0.81 0.84 0.83 0.84 0.01 ** * 13.3 13.3 13.1 13.1 13.5 13.6 13.7 13.8 0.14 NS ** MJ/kg dry matter NS, not significant; P <0.10; * P<0.05; ** P<0.01; *** P<0.001 Recent Advances in Animal Nutrition in Australia, Volume 13 (2001)