Methionine replacement value of N-acetylmethionine and homocysteinethiolactone hydrochloride for growing rats
Amos, H.E.; Schelling, G.T.; Digenis, G.A.; Swintosky, J.V.; Little, C.O.; Mitchell, G.E.
Journal of Nutrition 105(5): 577-580
1975
ISSN/ISBN: 0022-3166 PMID: 1127468 Document Number: 95032
The ability was studied of young growing rats to absorb DL-homocysteinethiolactone hydrochloride (HCTL-HCl) and N-acetyl-DL-methionine (NAM) and to use them for growth when deprived of methionine. The duodenum and ileum of the anaesthetised rats fasted for 16 to 24 h were cannulated and the absorption of HCTL-HCl and NAM was measured while the rats were still unconscious. Both compounds were readily absorbed. Intestinal half-times were 24 min for HCTL-HCl and 44 for NAM. Adding molar equivalents of 0.2 or 0.4% methionine to a 0.2% methionine basal diet given freely to the rats resulted in 28-day gains that were 83.2 and 91.1%, respectively, for HCTL-HCl and 94.6 and 99.8% for NAM of the average gain resulting when DL-methionine was added at equivalent amounts. Feed efficiencies were significantly improved over those of rats on the basal diet. Increasing the HCTL-HCl to 0.6% reduced feed intake and gain but not feed efficiency.