Development of a Novel Enzymatic Pretreatment for Improving the Digestibility of Protein in Feather Meal

This study describes the process of developing an enzymatic pretreatment to improve the nutritional value of feather meal (FeM). In a first experiment, a full factorial design was used to examine the effects of various incubation conditions on the solubilization of nitrogen in FeM. We incubated FeM for 3 h with various levels of a commercial alkaline serine protease (Savinase® 16L), sodium sulphite (Na2SO3), and digestion buffer. A Savinase® 16L level of 3% (%FeM v/w), Na2SO3 level of 3% (%FeM w/w), and digestion buffer level of 500% (%FeM w/w) were identified as the optimal conditions. Under these optimal conditions, 45% of the nitrogen in FeM was solubilized. In a second experiment, we evaluated the effect of more economically sustainable incubation conditions on the in vitro digestibility of protein (pepsin-HCl digestibility and multistep protein evaluation) in FeM. Two FeMs were incubated with 0.5% Savinase® 16L (%FeM v/w), 2% Na2SO3 (%FeM w/w), and 200% buffer (%FeM w/w) for 24 h. The pretreatment improved pepsin-HCl digestibility by 7%–16% and the total tract degradable protein content by 14%–50%. Accordingly, this novel pretreatment could be applied in the animal feed industry to improve the nutritional value of FeM.