Production of an egg yolk antibody specific to microbial uricase and its inhibitory effects on uricase activity.

Ammonia gas produced from poultry manure can be a potential source of environmental pollution. Microbial uricase in poultry manure is an important target enzyme to reduce ammonia production because ammonia is mainly generated from the microbial decomposition of uric acid in the manure. Thus, the inhibition of microbial uricase is critical in preventing NH3 volatilization. A potential method of inhibiting uricase activity is the use of antibodies specific to microbial uricase. Therefore, this study was designed to evaluate 1) the production of the uricase-specific egg yolk antibody (IgY) from immunized hens and 2) the effect of the uricase-specific IgY on the activity of uricase. A total of 12 Single Comb White Leghorn hens were injected intramuscularly with uricase from Arthrobacter globiformis. The hens were immunized a second and third time at 1 and 2 wk, respectively, after the initial injection. The production of uricase-specific IgY was first detected at 2 wk after the initial immunization, and levels increased more than threefold at 4 wk. The method including water extraction, ammonium sulfate precipitation, and ethanol precipitation showed the most acceptable IgY purity and over 97% uricase-specific IgY recovery. Finally, the effect of the uricase-specific IgY on uricase activity was determined by a uricase assay. The slope ratio showed that the immune-IgY from the uricase-immunized hens and nonimmune IgY from nonimmunized control hens reduced uricase degradation by 58 and 43%, respectively, compared to the uricase treatment. The regression slope indicated that the immune IgY and nonimmune IgY treatments had a significant inhibitory effects on uricase activity compared to the uricase.