Table 10.

Hypothalamic catecholamine (ng/mg) and plasma inositol concentrations (µM) of broilers fed diets with increased nutrient density and/or phytase supplementation, Experiment 2¹.

			28 D of age		43 D of age
Treatment	Nutrient density2	Phytase, FTU/kg3	Dopamine	Serotonin	Dopamine	Serotonin	Plasma inositol
1	−	0	0.779	0.784	0.494	0.340	179
2	+	0	0.708	0.815	0.549	0.404	169
3	−	4,500	0.670	0.758	0.608	0.409	403
4	+	4,500	0.715	0.793	0.645	0.453	407
SEM4			0.064	0.097	0.040	0.063	23
Main effect of nutrient density
	−		0.724	0.771	0.551	0.374	291
	+		0.711	0.804	0.597	0.428	288
	SEM4		0.048	0.069	0.031	0.045	16
Main effect of phytase
		0	0.743	0.799	0.521	0.372	174
		4,500	0.693	0.775	0.627	0.431	405
		SEM4	0.048	0.069	0.031	0.045	16
Source of variation				Probabilities
Nutrient density × phytase			0.334	0.985	0.796	0.875	0.748
Treatment 1 vs. 3			0.205	0.850	0.034	0.448	< 0.001
Treatment 2 vs. 4			0.929	0.871	0.071	0.590	< 0.001
Treatment 3 vs. 4			0.594	0.801	0.481	0.628	0.895
Main effect of nutrient density			0.826	0.736	0.216	0.402	0.892
Main effect of phytase			0.399	0.804	0.008	0.361	< 0.001

¹Values are least-square means of 8 replicate pens with 2 birds per pen for catecholamine analysis and average of 4 birds per pen for plasma inositol analysis.

²− = without increased nutrient density, + = with increased nutrient density; diets with increased nutrient density were formulated to contain 0.007, 0.015, 0.013, 0.021, 0.024%, and 61 kcal/kg higher digestible SAA, Lys, Thr, Val, Ile concentrations, and AME_n (obtained from Experiment 1), respectively, compared with the control diet.

³One unit of phytase activity (FTU) is the quantity of enzyme to liberate 1 µmol of inorganic phosphate per minute from 0.0051 mol/L sodium phytate at pH 5.5 and 37°C.

⁴Pooled standard error of the mean.