1.Overview
According to the Agricultural Industry Standard NY/T915-2004 "Hydrolyzed Feather Meal for Feedstuff" of the People's Republic of China, hydrolyzed feather meal for feed is defined as a powdery substance made from the depilated feathers of poultry carcass and the hair stalks after the selection of the production of down products, which are cleaned, hydrolyzed under high temperature and high pressure, dried and crushed.
The basic composition of feather meal is protein, mainly Yong protein. Less digestible in its natural state. The disulfide bond (-S-S-) and the sulfur-hydrogen bond in the structure of the feather meal were broken by hydrolyzing the feather with hydrolyzing technology. The protein in the feather was hydrolyzed locally and the chemical structure of the feather fiber was changed. Thus, it can improve the utilization rate of protein, palatability and fluidity of feather meal, and it is easy to digest for livestock and poultry. Reduce the cost of livestock and poultry feed and aquatic feed.
2．Processing technology of feather meal
Hydrolyzed feather meal mainly relies on the control of time, pressure and temperature during the hydrolysis process. The processing process is as follows: collect feathers, remove dust and clean them, put them in a hydrolysis tank, and hydrolyze them under high temperature and high pressure conditions. The technology is relatively advanced, and the outstanding feature is that it completely breaks the stable spatial structure of feather keratin protein, thereby turning it into a soluble protein that can be digested and absorbed by livestock and poultry, with a digestibility of over 75%. However, due to the breakage of the disulfide bond after hydrolysis, cystamine The acid content is reduced.
An important factor affecting the quality of hydrolyzed feather meal is the degree of hydrolysis. Feather meal must be processed for a long enough time to break the disulfide bond between cystines, but the hydrolysis is too high or the time is too short to cause insufficient hydrolysis to produce the best results. The best effect should be hydrolyzed feather meal with a digestibility of 70-80% (Ministry of Agriculture industry standard). If the hydrolysis is excessive (that is, the digestion rate of pepsin reaches 85%), too much cystine chemical bond is destroyed, and too much sulfur-containing amino acids will be lost, resulting in unnatural chemicals. These substances can be digested by pepsin under laboratory conditions, but cannot be used by animals. As a result, the digestibility of amino acids is low. On the contrary, if the hydrolysis is insufficient (that is, the pepsin digestion rate is less than 65%), the spatial structure of keratin cannot be broken, which is not conducive to the digestion and absorption of livestock and poultry, and it also causes low amino acid digestibility.
The physical properties of feather meal vary with the feather raw materials used. The feathers are light in color and the feather meal produced is light golden yellow; the feathers are dark in color and the feather meal produced is dark brown and black.
