Poultry feather hydrolysate as a protein source for growing rats

Abstract

Feather protein has been considered as a protein complement for animal diets, since it is largely available as a by-product of poultry processing. In this work, a feather protein hydrolysate produced by the keratinolytic microorganism Vibrio sp. kr2 was evaluated as a feed additive. Wistar rats were fed seven experimental diets (n = 6 rats per diet) containing different protein sources: casein (CAS), soybean protein, feather hydrolysate, feather meal, and soybean protein supplemented with 10 or 20% (w/w) feather hydrolysate, and 20% feather hydrolysate supplemented methionine. Values for weight gain, feed ingest, true digestibility, feed:gain ratio, Protein Efficiency Ratio and Net Protein Ratio were similar for diets containing soybean protein and 20% feather hydrolysate supplemented methionine. Lowest values for all nutritional parameters were observed for diets containing soybean protein supplemented with 10 or 20% (w/w) feather hydrolysate, feather hydrolysate and feather meal. Protein source had a considerable influence in the final weight of liver, kidney and hearth, although no significant differences were observed for brains. These results indicate that feather hydrolysate may be useful as supplementary protein in feed formulations