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Abstract The objective of this study was to investigate the influence of adding graded levels of a new biosynthetic bacterial 6-phytase on nutrient digestibility, phytate disappearance and growth performance in weaned piglets. A total of 192 male weaned piglets with initial body weight of 8.70 ± kg, distributed in a randomized block design with four treatments and 24 replicate pens with 2 animals each for 42 d. The experimental diets included a phosphorus and Ca deficient diet (STTD of P/Ca = 0.21%/0.58% and 0.19%/0.54%, respectively, in post-weaning 1 and 2 diets) containing 0 (a control diet), 500, 1,000 or 1,500 FTU/kg diet. The diets were fed into 2 phases: post-weaning 1 and 2 from 1 to 14 and 15 to 42 d, respectively. Body weight and feed intake were measured at the end of each phase, and average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated for the overall experimental period. On d 42, ileal digesta samples were collected from 1 piglet/pen (n = 12 samples/treatment) for apparent ileal digestibility (AID) of Ca, P, and amino acids and phytate disappearance determination. Supplementation of diet with phytase from 0 to 1500 FTU/kg diet linearly improved (P 0.01) AID of Ca. Both linear and quadratic effects (P 0.001) was observed for AID of P and phytate-P. Increasing level of phytase supplementation resulted in linear and quadratic increases of Arg, His, Ile, Leu, Lys, Phe, Thr, Trp, Val, Ala, Asp, Cys, Glu, Ser, Tyr and total amino acids. Phytase supplementation increased (P 0.0001) linearly Met and Pro, with an AID of Met showing a tendency (P = 0.09) for a quadratic increase. In addition, increasing phytase dose linearly increased (P = 0.006) the overall ADFI and ADG and decreased (P 0.001) F:G ratio. Also, a tendency (P = 0.07) for quadratic effect of phytase was also observed on F:G ratio. These findings highlight that the supplementation of diets with the new bacterial 6-phytase significantly enhanced the utilization of nutrients, disappearance of phytate and performances of weaned piglets in a dose dependent manner.
Jlali et al. (Wed,) studied this question.