Table 4.

Effects of long-term protein restriction on growth performance and carcass traits of Shaziling pigs.

Item	Dietary Levels of Protein					SEM	p-Value
	+20%	+10%	0	−10%	−20%		ANOVA	Linear	Quadratic
Initial weight, kg	8.74	8.84	8.99	8.54	8.78	0.33	1.00	0.93	0.99
Final weight, kg	84.95	80.49	84.28	85.83	81.96	1.87	0.90	0.96	1.00
ADFI, kg/d 1	1.74	1.76	1.72	1.78	1.70	0.04	0.97	0.87	0.95
ADG, kg/d 2	0.41	0.39	0.40	0.42	0.40	0.01	0.78	0.97	0.99
F:G 3	4.19	4.25	4.28	4.24	3.92	0.09	0.68	0.37	0.34
Carcass length, cm	81.66	80.24	79.41	80.45	79.25	0.56	0.68	0.24	0.45
Carcass weight, kg	46.29	45.94	45.99	48.2	46.24	1.08	0.94	0.80	0.96
Dressing percentage, %	54.45	54.29	55.33	56.23	56.04	<0.01	0.59	0.12	0.30
Backfat thickness, mm	22.98	20.32	25.64	26.84	20.99	0.80	0.11	0.75	0.29
Loin eye area, cm2	10.97	12.02	13.08	12.25	11.46	0.55	0.81	0.80	0.47
Lean percentage, %	38.32	38.59	37.57	35.39	40.62	<0.01	0.19	0.77	0.31
Fat percentage, %	35.90	34.45	37.92	38.36	35.56	<0.01	0.50	0.59	0.59

¹ ADFI = Average daily feed intake. ² ADG = Average daily gain. ³ F:G = Feed:gain.