Table 1. Animal performance of Hu sheep used for RNA and metagenomics sequencing.

Item			Breast milk-fed	Starter feed-fed	P-value
Growth performance	BW (kg)		8.49 ± 1.94	12.05 ± 2.72	0.026
	ADG (g/d)		0.13 ± 0.01	0.18 ± 0.01	0.010
Rumen morphology	WRR (g)		98.32 ± 27.59	196.72 ± 35.62	<0.001
	VRR (mL)		894.6 ± 320.86	1500.7 ± 291.92	0.007
	PH (μm)		659.40 ± 19.97	1003.33 ± 24.95	<0.001
	PW (μm)		624.74 ± 40.02	474.90 ± 18.79	0.053
	MT (μm)		807.45 ± 35.26	849.62 ± 39.59	0.429
Rumen fermentation parameters	pH		5.91 ± 0.10	5.30 ± 0.04	0.130
	Total VFA (mmol/L)		33.05 ± 5.52	113.24 ± 7.99	<0.001
	VFA proportion (mol/100 mol)	Acetate (A)	58.45 ± 9.24	50.67 ± 5.64	0.015
		Propionate (P)	26.98 ± 5.13	32.05 ± 6.63	0.025
		Butyrate	8.65 ± 1.50	11.78 ± 2.66	<0.001
		Isobutyrate	0.97 ± 0.81	0.31 ± 0.23	0.011
		Valerate	2.63 ± 1.21	3.84 ± 0.96	0.007
		Isovalerate	2.32 ± 2.07	1.34 ± 1.22	0.152
		A:P	2.32 ± 0.88	1.67 ± 0.49	0.028
	ruminal metabolic parameters (mg/100 mL)	Nitrogen	929.44 ± 290.70	4267.08 ± 558.99	<0.001
		Ammonium nitrogen	13.48 ± 3.55	22.66 ± 1.70	<0.001
		Urea nitrogen	2.68 ± 0.04	8.97 ± 1.44	<0.001
		Protein nitrogen	913.29 ± 236.48	4235.44 ± 423.10	<0.001
Enzymes activity of rumen microorganisms	Proteinase (U/mg)		0.017 ± 0.001	0.007 ± 0.000	<0.001
	Amylase (U/mg)		0.294 ± 0.021	0.585 ± 0.034	<0.001
	carboxymethylcellulase (U/mg)		0.019 ± 0.002	0.034 ± 0.001	<0.001

BW – body weight. ADG –average daily gain. WRR –weight of the reticulo-rumen. VRR –volume of the reticulo-rumen. PH –papilla height of the rumen. PW –papilla width of the rumen. MT –muscular thickness of the rumen. P-values were calculated using Student’s t-test.