Table 1.

Proximate composition and fatty acid profile for beef longissimus thoracis from steers fed a high-grain finishing diet with no supplementation, benzoic acid, active dry yeast, or a combination of benzoic acid and active dry yeast

	Treatment1
Item	CON	ACD	YST	AY	SEM	P-value
pH	5.45	5.44	5.45	5.42	0.02	0.39
Proximate composition
Moisture, %	71.72	71.50	71.55	71.77	0.56	0.98
Intramuscular lipid, %	5.44	5.59	5.36	5.21	0.71	0.98
Fatty acid composition, mg/100 g sample
Total SFA2	7,285	8,085	7,395	7,113	571	0.64
Total MUFA3	10,145	10,945	10,685	9,712	711	0.60
Total PUFA4	977	868	951	915	51	0.41
n-6 PUFA5	818	700	798	749	46	0.24
n-3 PUFA6	159	168	153	165	8	0.50
Fatty acid composition, % of total fatty acids
Total SFA2	33.88	34.71	33.57	34.53	0.66	0.54
Total MUFA3	47.45	47.71	48.35	47.49	0.61	0.66
Total PUFA4	4.75	3.93	4.53	4.57	0.31	0.24
n-6 PUFA5	3.98	3.17	3.81	3.74	0.28	0.17
n-3 PUFA6	0.76	0.76	0.72	0.83	0.05	0.25
Fatty acid ratio
MUFA:SFA7	1.41	1.38	1.45	1.38	0.04	0.62
PUFA:SFA8	0.14	0.11	0.14	0.13	0.01	0.23
PUFA:MUFA9	0.10	0.08	0.09	0.10	0.01	0.26
n-6:n-3 ratio10	5.27a	4.14b	5.28a	4.53ab	0.28	0.01

^a-b Least square means within a row with different superscripts differ (P < 0.05).

¹ Treatments: CON (n = 15): control (not supplemented); ACD (n = 14): 0.5% of benzoic acid dietary inclusion on a DM basis (DSM Nutritional Products); YST (n = 15): 3g/hd/d of Saccharomyces cerevisiae (Vistacell, AB Vista, Marlborough, UK); AY (n = 13): 0.5% of benzoic acid dietary inclusion on a DM basis (DSM Nutritional Products) and 3 g/hd/d of Saccharomyces cerevisiae (Vistacell, AB Vista, Marlborough, UK).

² Total saturated fatty acids (SFA) = C6:0 + C7:0 + C8:0 + C9:0 + C10:0 + C11:0 + C12:0 + C14:0 + C15:0 + C16:0 + C17:0 + C18:0 + C19:0 + C20:0 + C22:0 + C24:0.

³ Total monosaturated fatty acids (MUFA) = C12:1 + C14:1 + C15:1 + C16:1 + C17:1 + C18:1 + C19:1 + C20:1 + C22:1 + C24:1.

⁴ Total polyunsaturated fatty acids (PUFA) = C18:2 + C18:3 + C18:4 + C20:2 + C20:3 + C20:4 + C20:5 + C22:2 + C22:4 + C22:5 + C22:6.

⁵ Total n-6 polyunsaturated fatty acids.

⁶ Total n-3 polyunsaturated fatty acids.

⁷ MUFA:SFA = total monounsaturated fatty acids ÷ total saturated fatty acids.

⁸ PUFA:SFA = total polyunsaturated fatty acids ÷ total saturated fatty acids.

⁹ PUFA:MUFA = total polyunsaturated fatty acids ÷ total monounsaturated fatty acids.

¹⁰ n-6 fatty polyunsaturated fatty acids ÷ n-3 polyunsaturated fatty acids.