Effects of Urease Immunization of Growing Pigs upon Performance and Blood and Intestinal Ureolysis

Abstract

Three trials using 81 pigs were conducted to study the effects of urease immunization upon the following criteria: feed intake, gain, feed efficiency, plasma urea and ammonia, intestinal urease and ammonia and serum antiurease. Urease prepared from jackbean meal was injected intraperitoneally in Trials I and III, while Sigma urease type II powder was used in Trial II. Starting doses ranged from 0.1 to 10 modified Sumner units per pound of body weight with from 6 to 12 injections increasing by arithmetic progression. A corn-soybean ration fortified with minerals and vitamins was fed. Gain and feed efficiency of immunized pigs were not improved in Trials II and III; however, there was some improvement in Trial I at the 10-unit level. Plasma urea N levels did not differ significantly between treatments in any of the trials. In general, ammonia N levels of plasma were not different between treatments; however, the 0.5-unit level (low) in Trial III significantly reduced plasma ammonia levels during the latter part of the trial. Urease immunization was effective in stimulating antibody production (antiurease) and in reducing intestinal urease activity. In general, all levels of urease injected were equally effective in producing antiurease with some evidence of partial inhibition of antibody production at the higher urease levels. Urease immunization appeared to have no effect on the utilization of urea by the pig. Higher urea N levels and lower ammonia N levels were observed in pigs fed rations with added urea. Gain, feed intake and feed efficiency were decreased when more than 35% of dietary N from soybean meal was replaced with urea. Copyright © 1964. American Society of Animal Science . Copyright 1964 by American Society of Animal Science