TABLE 2.

Values of ventilation ($\stackrel{.}{\text{V}}$_E), tidal volume (V_T), respiratory frequency (f_R), oxygen consumption ($\stackrel{.}{\text{V}}$O₂), and ventilatory equivalent ($\stackrel{.}{\text{V}}$_E/$\stackrel{.}{\text{V}}$O₂) of 3 and 14 days-old female and male chickens that were incubated at control (CT; 37.5°C) or at higher (HT; 39°C) or lower (LT; 36°C) temperatures during 6 h/day, from day 0 to 5 of incubation.

		LT	CT	HT	P
3 days-old
$\stackrel{.}{\text{V}}$E	♀	49.6 ± 6.4	53.2 ± 4.1	57.1 ± 4.5	ns
(mL.min–1)	♂	38.8 ± 3.9 b	54.0 ± 3.3 a	47.5 ± 3.4 ab	<0.05
VT	♀	0.6 ± 0.1	0.6 ± 0.1	0.6 ± 0.1	ns
(mL)	♂	0.6 ± 0.1	0.7 ± 0.1	0.6 ± 0.1	ns
fR	♀	111.5 ± 18.4	85.5 ± 11.8	91.0 ± 11.1	ns
(min–1)	♂	79.6 ± 13.5	105.5 ± 22.7	86.9 ± 14.0	ns
$\stackrel{.}{\text{V}}$O2	♀	1.6 ± 0.2	1.9 ± 0.1	1.9 ± 0.1	ns
(mL.min–1)	♂	1.7 ± 0.2	1.7 ± 0.1	1.7 ± 0.1	ns
$\stackrel{.}{\text{V}}$E/$\stackrel{.}{\text{V}}$O2	♀	27.1 ± 2.2	29.4 ± 2.5	34.1 ± 1.8	ns
	♂	25.3 ± 2.6	32.4 ± 1.7	28.1 ± 2.4	ns
14 days-old
$\stackrel{.}{\text{V}}$E	♀	346.9 ± 22.5 a	318.4 ± 19.3 a	229.8 ± 19.9 b	<0.05
(mL.min–1)	♂	337.8 ± 26.0	320.0 ± 18.7	249.6 ± 26.9	ns
VT	♀	5.1 ± 0.5	5.0 ± 0.4	3.4 ± 0.5	ns
(mL)	♂	5.4 ± 1.0	5.9 ± 0.5	3.2 ± 1.0	ns
fR	♀	70.5 ± 3.5	65.5 ± 5.4	70.2 ± 6.1	ns
(min–1)	♂	64.8 ± 6.6	57.2 ± 3.6	81.1 ± 8.1	ns
$\stackrel{.}{\text{V}}$O2	♀	8.9 ± 0.3 a	9.3 ± 0.2 a	7.7 ± 0.3 b	<0.05
(mL.min–1)	♂	10.6 ± 0.5 ab	10.5 ± 0.4 a	7.4 ± 0.5 b	<0.05
$\stackrel{.}{\text{V}}$E/$\stackrel{.}{\text{V}}$O2	♀	38.9 ± 2.1	34.2 ± 3.1	29.6 ± 1.8	ns
	♂	33.7 ± 2.0	31.1 ± 3.1	31.1 ± 1.4	ns

Different letters represent statistical differences in comparing chicks of the same sex and parameter. Significance level (P ≤ 0.05). ns, not significant (P > 0.05). [3d ♀ (n = 19); 3d ♂ (n = 21); 14d ♀ (n = 20); 14d ♂ (n = 20)].