Table 3.

Qualitative assessments of breast meat from broiler chickens fed diets containing different vitamin A supplementation.

		Vitamin A supplementation (IU/kg)
	Supplementation1	0	6,000	16,000	26,000	36,000	46,000	Average2	SEM	P (Anova)	P (Test F)	P (Regression)
SF (kgf)	T – 21	3.754	3.468	3.747	3.673	4.828	3.930	3.899	1.33108	0.4105	0.8842	0.9198
	T – 42	3.578	3.856	3.265	3.981	4.295	4.171	3.858	1.53301	0.7750		0.7805
CL (%)	T – 21	34.711	35.290	34.377	34.267	36.066	35.840	35.109	3.51894	0.8718	0.1395	0.5429
	T – 42	32.172	33.671	32.792	35.381	36.326	32.793	33.878	4.51713	0.4008		0.1941
WHC (%)	T – 21	66.381	67.967	68.003	66.567	66.552	66.230	66.952	3.52441	0.8294	0.4228	0.5051
	T – 42	68.569	67.616	66.086	66.113	69.350	67.652	67.564	4.07553	0.5431		0.2753
pH 15 min	T – 21	6.486	6.473	6.398	6.378	6.365	6.516	6.436	0.11868	0.0620	0.5208	0.0041 (Q)
	T – 42	6.494	6.360	3.449	6.456	6.528	6.441	6.454	0.15642	0.4031		0.9780
pH 24 h	T – 21	6.004	5.970	6.018	5.915	5.911	5.925	5.959	0.14360	0.5120	0.9555	0.8332
	T – 42	6.003	5.961	6.010	6.020	5.949	6.064	6.001	0.20573	0.8929		0.6848

Abbreviations: CL, cooking loss; L, linear; pH 15 min, pH breast meat at 15 min postmortem; pH 24 h: pH breast meat 24 h postmortem; Q, Quadratic; SF, shear force; WHC, water holding capacity.

pH 15 min (T-21 d): 0.0000000000660904 vit A² - 0.00001180 vit A + 6.50960; R²: 0.21; Vit. A for maximum response: 23,678; Minimum response: 6.37.

¹T-21d: birds supplemented with treatments in the period of the 4 to 21 days of age; T-42 d: birds supplemented with treatments in the period of the 4 to 42 days of age;

²Test F (P ≤ 0.05) for comparing the averages of vitamin A supplementation times.