Separation Procedure of Odorous Substances from Solid Swine Manure

When rats were fed a low protein diet containing 3% or more of phenylalanine, their growth rate and food intake were depressed, and eye and paw lesions which were similar to those in tyrosine toxicity developed in all rats. Their liver phenylalanine hydroxylase activity was depressed in proportion to the dietary phenylalanine content, and dihydropteridine reductase activity was in a great excess over hydroxylation activity, so phenylalanine hydroxylase activity seemed to be limited firstly in the degradation of phenylalanine. Excessive phenylalanine was accumulated, and the tyrosine concentration was higher than that of phenylalanine in the plasma and tissues of rats fed a diet containing 2% or more of phenylalanine. When p-Cl-phenylalanine (p-Cl-Phe) was injected to the rats fed excess phenylalanine, the phenylalanine hydroxylase was depressed, the concentration of tyrosine in the body was lowered, and the development of eye and paw lesions was prevented completely. The development of eye and paw lesions seemed to be associated with the extremely elevated tyrosine concentration in the body.