Amino Acid Availability and Protein Quality of Canola anad Rapeseed Meal for Pigs and Rats

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Abstract
The apparent ileal and fecal availabilities of amino acids (AA) in meals of canola (varieties Regent and Candle, both low in glucosinolates) and rapeseed (variety Turret, high in glucosinolates), and in soybean meal were determined in barrows fitted with ileocecal re-entrant cannulas. The barrows were fed a cornstarch-based diet formulated to contain 14% protein. True availabilities were calculated from metabolic fecal and ileal AA levels obtained in previous studies. There were no significant differences between the true ileal or true fecal availabilities of AA in the meals from canola (CM) and rapeseed (RSM). However, the true ileal availabilities of AA were higher in soybean meal (SBM) than in CM or RSM; among the indispensable AA, higher values were obtained for lysine (P<.01) and isoleucine (P<.05). The true ileal availabilities of the more important indispensable AA, lysine, threonine, and methionine, were 88.3, 81.1 and 89.5%, respectively, in SBM and 77.7, 72.7 and 84.5%, respectively, in CM and RSM. The estimates of true availabilities of AA were higher when determined by the fecal rather than the ileal analysis method; among the indispensable AA, the differences were largest for threonine and valine (9.8 and 11.6 percentage units, respectively, in SBM and 11.6 and 10.9 percentage units, respectively, in CM and RSM). Studies with rats, in which the protein efficiency ratio method was used showed the quality of protein in CM to be superior to that of SBM, despite the lower protein digestibility of CM. Copyright © 1982. American Society of Animal Science . Copyright 1982 by American Society of Animal Science