Suitable condition of enzymatic reactivity for determining the digestibility of feedstuffs phosphorus by dialysis tube method

Abstract

In order to develop a new method for determining the phosphorus (P) digestibility in vitro in feedstuffs by dialysis tube, a L₃₂(4⁹) orthogonal experiment with eight factors (4 levels for each factor) and a single factor experiment on the enzymatic reactivity were carried out. The sequence of significance of the eight factors on sample-P dialyzability was as follows: trypsin digestion for 6 h, dialyzing solution at 100 mL, pH of pepsin solution at 2.5, pepsin concentration at 2000 UmL^-1 pepsin digestion for 100 min, at temperature of 35°C, trypsin concentration at 1625 UmL^-1, and pH of trypsin solution at 6.5, respectively. And in vitro dialyzabilities of P in soybean meal, barley, sorghum, peanut meal, and rapeseed meal were (36.91 ± 0.58)%, (27.28 ± 0.94)%, (26.95 ± 0.58)%, (30.51 ± 0.83)%, and (20.82 ± 1.09)%, respectively.

Keywords

phosphorus / in vitro / digestibility / suitable conditions of enzymatic reactivity