. 2015 Sep 3;29(2):211–218. doi: 10.5713/ajas.15.0166

Table 4.

Least squares mean (±SE) of concentrations of acetic, propionic, butyric, valeric and isovaleric acids during in vitro oat straw rumen fermentation

Volatile fatty acid (mMol)	Treatment			SEM	Trend		Treatment effect

	Time (h)	Control	Yeast		L	Q
Acetic acid	0	24.40^a	20.00^a	1.97	***	*	NS
	4	24.56^a	26.82^a	1.97			NS
	8	29.50^a	37.42^b	1.97			***
	12	32.36^a	40.89^b	1.97			***
	24	45.04^a	48.84^a	1.97			NS
Propionic acid	0	8.55^a	6.72^b	0.58	***	NS	*
	4	8.22^a	9.09^a	0.58			NS
	8	9.99^a	11.90^b	0.58			*
	12	11.50^a	13.46^b	0.58			*
	24	17.26^a	17.79^a	0.58			NS
Butyric acid	0	5.81^a	4.48^b	0.42	***	**	*
	4	5.27^a	6.23^a	0.42			NS
	8	6.73^a	8.12^b	0.42			*
	12	7.61^a	8.50^a	0.42			NS
	24	9.73^a	9.68^a	0.42			NS
Valeric acid	0	0.50^a	0.45^a	0.06	***	NS	NS
	4	0.46^a	0.63^a	0.06			NS
	8	0.60^a	0.99^b	0.06			***
	12	0.67^a	1.31^b	0.06			***
	24	0.96^a	1.77^b	0.06			***
Isovaleric acid	0	0.44^a	0.47^a	0.08	*	**	NS
	4	0.42^a	0.46^a	0.08			NS
	8	0.48^a	0.78^b	0.08			**
	12	0.58^a	1.02^b	0.08			***
	24	0.99^a	1.69^b	0.08			***

SEM, standard error of the mean; L, linear trend across fermentation times; Q, quadratic trend across fermentation times; NS, non significant.

Different letters in the same row indicate significant differences (* p 0.05; ** p 0.01; *** p 0.001) between treatments.

Means (n = 40) in rows with the same superscript are not significantly different (ns) due to treatment effect.