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Effect of betaine on plasma amino acids in Alpine and Angora kids

R. Puchala, T. Sahlu, M.J. Herselman, J.J. Davis and S.P. Hart.

E (Kika) de la Garza Institute for Goat Research, Langston University, Oklahoma.

Five Angora and five Alpine kids (mean age 120 d) were fitted with indwelling jugular catheters to study the effect of betaine on plasma methionine and related metabolites. Betaine (0, .1, .2, .5 g kg-1 BW) was administered as a single injection. Blood samples were taken -30, 0, 10, 30, 50, 70 and 90 min post-injection. Alpine kids had higher initial levels of plasma methionine than Angora kids (29.0 vs 21.3 μM; P< .05). There were differences in utilization of betaine between the two goat breeds. Plasma methionine of Alpine kids increased 10 min after injection of .1 or .2 g kg-1 BW of betaine (34.7 μM; P< .05) whereas .2 g kg-1 BW of betaine was required to increase plasma methionine in Angora kids (23.2 μM; P < .10). Betaine did not affect plasma cystine or cystathionine levels although cystine was higher in Alpine kids than in Angora kids (44.4 vs 22.9 μM; P< .05). Plasma S-adenosylhomocysteine and glycine were increased 30 min after injection of .2 g kg-1 BW of betaine in both breeds of goats (2.9 vs 6.0 and 659 vs 821 μM; P<.05 for Alpine, 2.1 vs 5.1 and 846 vs 920 μM; P<.05 for Angora, respectively). The only other amino acid that was affected was serine which increased 70 min after betaine injection. There were no differences in plasma triglycerides between breeds (17.5 mg dL-1) and injection of betaine (.2 g kg-1 BW) did not change its level. An overloading effect was observed with .5 g kg-1 BW of betaine in both breeds of goats that led to lack of changes in methionine level. This study indicated that increased plasma methionine level may not only be due to remethylation of homocysteine, but betaine may also spare methionine by substituting for it in some metabolic processes.



J. Anim. Sci. 72(Suppl. 1), 77