Table 3.

Molar proportion of ruminal short-chain fatty acids (SCFA), ammonia, and ruminal pH of rumen-cannulated Bos indicus Nellore steers receiving forage-based diets supplemented or not (CON, n = 8) with narasin (NAR, n = 8), lasalocid (LAS; n = 8), or virginiamycin (VRM; n = 8) for 140 days (Exp. 1)

	Treatments1					P-value2
Item	CON	NAR	LAS	VRM	SEM	Treatment	Day	T × D
Rumen pH	6.85b	6.79b	6.84b	6.98a	0.04	0.03	<0.01	0.19
Ammonia, mg/dL	4.18	4.28	4.25	4.87	0.77	0.11	<0.01	0.17
Total SCFA, mM	87.13b	101.51a	87.17b	90.35b	6.92	0.02	<0.01	<0.01
SCFA, mM/100mM3
Acetate	74.91a	73.14b	74.61a	74.98a	0.38	<0.01	<0.01	<0.01
Propionate	14.53b	16.28a	14.84b	14.49b	0.22	<0.01	<0.01	<0.01
Butyrate	7.80	7.75	7.62	7.71	0.14	0.78	<0.01	0.54
Isobutyrate	0.87	0.87	0.88	0.89	0.02	0.84	<0.01	0.47
Valerate	0.87	0.85	0.85	0.88	0.08	0.95	<0.01	0.87
Isovalerate	1.05	1.10	1.11	1.09	0.02	0.27	<0.01	0.11
Acetate:propionate	5.18b	4.52a	5.04b	5.20b	0.06	<0.01	<0.01	<0.01

¹CON, no feed additives; NAR, inclusion of 13 mg/kg of dry matter (DM) of narasin (Zimprova; Elanco Animal Health, São Paulo, SP, Brazil); LAS, inclusion of 20 mg/kg of DM of lasalocid (Taurotec; Zoetis, Sao Paulo, SP, Brazil; n = 8); VRM, inclusion of 20 mg/kg of DM of virginiamycin (V-Max; Phibro Animal Health Corporation, Guarulhos, SP, Brazil; n = 8).

² P-value for treatment, day, and treatment × day interaction (T × D).

³On day 0 (immediately prior to the beginning of the experimental period and first treatment offer), 28, 56, 84, 112, and 140 of the experimental periods at 0, 6, and 12 h after feeding concentrate + treatments, ruminal fluid samples were collected (approximately 100 mL).