Table 3.

Effect of polyethylene glycol (PEG) treatment on in vitro gas production and ammonia nitrogen (NH₃-N) from green and black tea by-product silage at 24 h after incubation

Attributes	Day 0	Day 45			SEM
		10°C	20°C	30°C
Gas production (mL/500 mg DM)
Green tea by-product silage
No PEG	83.9	76.4a	68.2b	63.8b	1.9
With PEG	85.3	77.3a	69.7b	64.0c	1.2
Increase (%)	1.7	1.1	2.2	0.4	1.8
Black tea by-product silage
No PEG	58.4	54.8a	47.7b	43.9c	0.6
With PEG	65.2	61.2a,*	52.8b,*	48.5c,*	0.3
Increase (%)	11.7	11.6	10.7	10.6	1.9
NH3-N (mg/40 mL/500 mg DM)
Green tea by-product silage
No PEG	6.3	7.0b	8.2a	8.1a	0.4
With PEG	9.0	10.0b,*	11.7a,*	11.1ab,*	0.9
Increase (%)	43.3	42.2	43.6	38.0	3.5
Black tea by-product silage
No PEG	5.3	4.6b	5.5a	5.7a	0.4
With PEG	8.3	8.3b,*	9.2a,*	8.6ab,*	0.2
Increase (%)	56.7	82.2a	65.8b	51.8c	3.4

SEM, standard error of the mean; DM, dry matter.

Means with the different letter (a–c) in a row are significantly different (p<0.05).

^*Significantly different between No PEG (p<0.05).