Keratins as Sources of Protein for the Growing Chick: 4. Processing of Tannery By-Product Cattle Hair into a Nutritionally Available High Protein Meal: Metabolizable Energy, Amino Acid Composition and Utilization in Practical Diets by the Chick

Abstract

BOTH feathers and hog hair can be converted through high pressure steam processing into nutritionally valuable high protein meals (Binkley and Vasak, 1950; Naber, 1961; Moran et al., 1966, 1967 a). The only outstanding change in these keratin products upon treatment; other than substantial meal density increases, was the significant reduction in cystine concentration (Gregory et al., 1956; Davis et al., 1961; Moran et al., 1967b). Because feathers and hog hair supported chick growth and contained reasonable quantities of metabolizable energy only when these keratin sources were autoclaved long enough to emit hydrogen sulfide and go to a structurally flaccid state, Moran et al. (1966, 1967 b) contended that reduction of the large inherent quantities of molecular structure stabilizing cystine was a prerequisite to nutritional availability. Unpublished observations mentioned by Almquist et al. (1966) with another keratin product supports the aforementioned contention. Pressure-steam treatment of raw hoof and horn meal .