Table 2.

Regression equations on the influence of saponin-rich source addition level (S, in mg/g DM) on ruminal fermentation parameters based on in vitro experiments

Response parameter	Dependent factor	n	Parameter estimates				Model statistics
			Intercept	SE intercept	Slope	SE slope	p-value	RMSE
Gas (mL/g)	S	70	196	15.8	−0.019	0.031	0.548
	S2				0.00019	0.00007	0.007	7.43
OMD (mg/g)	S	16	626	578.4	−0.34	0.182	0.095	20.62
pH	S	68	6.62	0.157	−0.0001	0.0001	0.639	0.13
NH3 ( mmol/L)	S	63	11.1	2.10	−0.006	0.0034	0.092	2.92
Total SCFA ( mmol/L)	S	89	75.3	5.96	0.010	0.0030	<0.001	2.74
C2 (% total)	S	87	63.5	1.60	−0.012	0.0017	<0.001	1.54
C3 (% total)	S	87	22.0	0.94	0.012	0.0021	<0.001	1.90
C4 (% total)	S	85	11.1	0.64	−0.0004	0.0011	0.740	0.97
C5 (% total)	S	51	2.81	0.440	−0.0002	0.0002	0.350	0.14
isoSCFA (% total)	S	53	3.00	0.505	−0.0001	0.0004	0.978	0.21
C2:C3	S	87	3.08	0.191	−0.0014	0.0003	<0.001	0.27
Log protozoa (104/mL)	S	56	4.73	0.207	−0.0006	0.0003	0.047	0.23

DM, dry matter; n, number of observation; SE, standard error; RMSE, root mean square error; OMD, organic matter digestibility; SCFA, short chain fatty acid; C₂, acetate; C₃, propionate; C₄, butyrate; C₅, valerate.