Methionine requirement of weanling Large White x Landrace pigs and determined by plasma urea concentration, nitrogen retention and some urinary nitrogenous components
Balogun, O.O.; Fetuga, B.L.
Journal of Nutrition 111(6): 1025-1032
1981
ISSN/ISBN: 0022-3166 PMID: 7241224 Document Number: 169737
The methionine requirements of weanling Large White .times. Landrace pigs fed a 20% protein cassava flour-soybean meal diet were evaluated using N balance, plasma urea concentration, urinary nitrogenous end products and the index.sbd.(allantoin/urinary urea) .times. protein intake [A/U .times. Ip]. Sensitivities of the response criteria to sex differences in methionine requirements were compared. Allantoin excretion consistently and significantly (P < 0.05) increased with increasing methionine levels to a maximum of 0.55% total methionine. Maximum N retention was observed in diets containing 0.55, 0.47 and 0.55% total methionine for castrated males, females and the pooled data for both sexes, respectively. Minimum urea concentration in plasma was obtained with the diets containing 0.55% methionine. The index, + A/U .times. Ip, showed that the diet was better utilized when it contained 0.63, 0.55 and 0.63% total methionine in castrates, females and combination of the 2 sexes, respectively.