Effect of glycine and vitamin supplementation on sulphur amino acid utilization by growing cattle.
Effects of glycine (Gly) and B-vitamins on sulphur amino acid (AA) utilization were studied in growing steers maintained under conditions where methionine (Met) was first limiting. Conditions were generated by limit feeding a diet low in ruminally non-degraded protein and abomasally infusing an AA mixture limiting in Met. Retained N tended (p = 0.07) to improve when steers received 10 mg folate, 10 mg vitamin B6, and 0.10 mg vitamin B12 daily. Hepatic vitamin B12 (p = 0.08) and folate (p = 0.05) concentrations increased with vitamin supplementation. In another trial, factorial treatments were 2 or 5 g/day L-Met and 0 or 50 g/day Gly infused abomasally. Retained N increased (p < 0.05) in response to Met, and responses were numerically larger in the presence of supplemental Gly. In a different trial, factorial treatments were 0 or 2.4 g/day L-cysteine (Cys) and 0 or 40 g/day Gly. Retained N was not affected by Cys in the absence of Gly, but was increased by Cys when Gly was supplemented (interaction, p = 0.01). B-vitamin status may affect sparing of Met by Cys. Supplemental Gly improved responses to supplemental Met and Cys.
Lambert
B D
BD
Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS, USA.
Titgemeyer
E C
EC
Löest
C A
CA
Johnson
D E
DE
D000018:Abomasum / Q000378:metabolism; D000603:Amino Acids, Sulfur / Q000378:metabolism* / Q000652:urine; D000818:Animals; D002417:Cattle / Q000254:growth & development* / Q000378:metabolism* / Q000652:urine; D018592:Cross-Over Studies; D019587:Dietary Supplements; D005243:Feces / Q000737:chemistry; D005998:Glycine / Q000008:administration & dosage*; D008297:Male; D008715:Methionine / Q000008:administration & dosage / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D011897:Random Allocation; D012417:Rumen / Q000378:metabolism; D014803:Vitamin B Complex / Q000008:administration & dosage*
D000603:Amino Acids, Sulfur; D014803:Vitamin B Complex; D008715:Methionine; D009584:Nitrogen; D005998:Glycine