TABLE 3.

Metabolite concentrations (AUC/mg protein) in liver tissue from Holstein cows individually fed a control diet or the control plus rumen-protected Met (0.9 g/kg dry matter intake) during the last 28 d before parturition¹

	Treatment		P value
Item	Control	Met	Treat	Time	Treat × Time
TCA cycle, AUC/mg protein
Acetyl-CoA	7.14 ± 0.28	7.48 ± 0.28	0.442	0.685	0.813
Succinyl-CoA	7.29 ± 0.18	7.29 ± 0.18	0.891	0.998	0.499
Malic acid	12.8 ± 0.08	13.7 ± 0.08	0.093	0.764	0.716
α-Ketoglutaric acid	10.21 ± 0.04	10.37 ± 0.04	0.084	0.375	0.526
Isocitric acid	5.87 ± 0.08	6.22 ± 0.08	0.063	0.084	0.827
Met and folic acid cycle, AUC/mg protein
Glycine	11.31 ± 0.05	11.21 ± 0.05	0.221	0.178	0.994
N-methylglycine	8.09 ± 0.07	8.17 ± 0.07	0.184	0.123	0.516
N,N-dimethylglycine	11.2 ± 0.16	11.2 ± 0.16	0.822	0.404	0.324
Betaine	9.24 ± 0.08	9.28 ± 0.08	0.814	0.002	0.403
Met	11.1 ± 0.06	11.3 ± 0.06	0.080	0.323	0.994
S-5′-adenosylmethionine	10.5 ± 0.21	10.3 ± 0.21	0.492	0.034	0.482
S-5′-adenosylhomocysteine	ND	ND
5-Methyltetrahydrofolic acid	7.85 ± 0.28	8.03 ± 0.28	0.564	0.010	0.510
Tetrahydrofolic acid	ND	ND
Folic acid	ND	ND
Vitamin B-12	ND	ND
Adenosine	9.21 ± 0.21	9.29 ± 0.21	0.822	0.301	0.674
Transsulfuration pathway, AUC/mg protein
Serine	11.83 ± 0.11	11.89 ± 0.11	0.743	0.630	0.202
Hypotaurine	9.38 ± 0.15	9.15 ± 0.15	0.284	0.181	0.443
Cysteine	9.24 ± 0.09	9.27 ± 0.09	0.390	0.253	0.564
Homocysteine	ND	ND
Vitamin B-6	ND	ND
Cystathionine	9.35 ± 0.14	9.36 ± 0.14	0.961	0.934	0.245
Glutathione	6.96 ± 0.46	8.31 ± 0.46	0.048	0.403	0.436
Taurine	9.74 ± 0.08	9.99 ± 0.08	0.101	0.305	0.891
Cysteinesulfinic acid	7.07 ± 0.28	6.83 ± 0.28	0.564	0.274	0.638

¹Values are means ± pooled SEMs, n = 10 per treatment group. ND, not detected; TCA, tricarboxylic acid.