Table 3.

Relative abundance (%) of 10 targeted rumen bacteria species and the 16S rRNA gene copy numbers of the total rumen bacterial community in the rumen solids-fraction of the most- (n = 6) and the least- (n = 6) efficient beef cattle on RFI testing for 70 d during the finishing period

Items1	RFI2		SE3	Sex		SE4	P-value
	Most-efficient animals	Least-efficient animals		Steers	Heifers		RFI	Sex	RFI × sex
Target bacterial species
A. lipolytica	1.80 × 10−4	9.00 × 10−5	0.27	1.20 × 10−4	1.30 × 10− 4	0.31	0.48	0.96	0.45
B. proteoclasticus	1.91 × 10−2	1.12 × 10− 2	0.22	1.33 × 10− 2	1.60 × 10− 2	0.25	0.47	0.80	0.66
E. ruminantium	9.13 × 10-2a	4.18 × 10-2b	0.10	9.09 × 10-2a	4.20 × 10-2b	0.11	0.05	0.05	0.84
F. succinogenes	2.90 × 10-4a	1.00 × 10-4b	0.13	3.00 × 10-4a	0.90 × 10-4b	0.14	0.03	0.02	0.79
M. elsdenii	7.00 × 10-5a	3.00 × 10-5b	0.12	4.00 × 10−5	5.00 × 10−5	0.12	0.04	0.73	0.35
P. bryantii	4.31 × 10−2	3.52 × 10−2	0.14	5.37 × 10−2	2.82 × 10− 2	0.16	0.67	0.20	0.40
S. ruminantium	1.25 × 10−1	1.17 × 10−1	0.08	1.21 × 10−1	1.20 × 10−1	0.09	0.80	0.97	0.95
S. amylolytica	0.70 × 10-4b	3.80 × 10-4a	0.14	2.40 × 10−4	1.20 × 10−4	0.14	< 0.01	0.16	0.83
S. bovis	5.63 × 10−3	6.75 × 10−3	0.25	6.30 × 10− 3	6.03 × 10− 3	0.29	0.83	0.96	0.48
S. dextrinosolvens	4.81 × 10−2	1.22 × 10−2	0.48	1.38 × 10− 2	4.26 × 10− 2	0.56	0.41	0.49	0.28
Bacteria density
The 16S rRNA gene copy numbers (log10)/ng DNA5	8.03b	8.07a	0.01	8.05	8.05	0.01	0.05	0.89	0.60

Means with different superscripts (^{a, b}) within row represent differences among overall RFI or sex effects (P ≤ 0.05)

¹Data were logit transformed to ensure normality of residuals

²RFI residual feed intake

³SE standard error of the mean for RFI effect

⁴SE standard error of the mean for sex effect

⁵16S rRNA gene copy number (log₁₀)/ng DNA