Effect of Tannin-Binding Agents (Polyethylene Glycol and Polyvinylpyrrolidone) Supplementation on In Vitro Gas Production Kinetics of Some Grape Yield Byproducts

Table 4

The parameters estimated from the gas production of grape yield byproducts with or without PEG or PVP.

Treatments	Estimated parameters
	a + b	c	ME	OMD	NEl	VFA
Grape pomace (GP)
Control	263.49^c	0.1073^a	12.40^b	59.85^b	0.406^b	1.024^b
GP + PEG	317.03^a	0.0921^c	13.66^a	68.05^a	0.423^a	1.229^a
GP + PVP	314.11^b	0.0972^b	13.62^a	67.82^a	0.422^a	1.223^a
SEM	0.118	0.0003	0.067	0.436	0.001	0.011
Raisin waste (RW)
Control	208.22^b	0.0976^c	10.79^b	50.32^b	0.367^b	0.799^b
RW + PEG	235.86^a	0.1082^a	11.43^a	54.50^a	0.376^a	0.903^a
RW + PVP	235.66^a	0.1028^b	11.49^a	54.89^a	0.376^a	0.913^a
SEM	0.0955	0.00014	0.105	0.688	0.001	0.017
Dried grape byproduct (DGB)
Control	239.43^c	0.0992^a	11.63^b	55.41^b	0.367^b	0.924^b
DGB + PEG	280.59^a	0.0939^c	12.51^a	61.22^a	0.379^a	1.069^a
DGB + PVP	252.24^b	0.0966^b	11.87^b	57.03^b	0.370^b	0.965^b
SEM	0.277	0.00003	0.166	1.082	0.002	0.027

GP: grape pomace, RW: raisin waste, DGB: dried grape pomace, ME: metabolizable energy (MJ/kg DM), OMD: organic matter digestibility (g/100 g DM), NE_l: net energy for lactation (Mcal/lb), VFA: volatile fatty acids (mmol), (a + b): potential gas production (mL/g DM) and c: rate constant of gas production during incubation (mL/h).
^a,b,cWithin a column, means without a common superscript letter differ (𝑃<0.05).