Table 3. The influence of nutrient densities and starch to lipid ratios on performance and carcass traits in broiler chickens from 7–27 days post-hatch.

Treatment	Nutrient density	Starch:lipid ratios	Weight gain (g/bird)	Feed intake (g/bird)	FCR (g/g)	Carcass weight (g/bird)	Carcass yield (%)	Carcass composition
								GE (MJ/kg DM)	Protein (% as-is)	Lipid1 (% as-is)	DM (% as-is)
1	Low	14	1645	2504	1.522	1601	90.0	27.3a	22.77	12.94a	39.68
2	Low	12	1539	2344	1.523	1564	89.7	24.9cd	22.68	9.13cd	39.09
3	Low	7	1510	2311	1.531	1545	89.9	25.4bcd	22.42	9.72bcd	38.51
4	Low	4	1348	2098	1.556	1390	89.6	25.6bc	22.48	10.25bc	39.48
5	Medium	14	1655	2306	1.393	1752	90.9	25.8bc	22.75	10.38bc	39.06
6	Medium	12	1621	2255	1.390	1612	89.4	25.3bcd	22.99	9.92bc	40.20
7	Medium	7	1603	2205	1.374	1585	90.2	25.4bcd	22.70	9.89bcd	39.19
8	Medium	4	1491	2083	1.398	1501	89.5	25.9bc	22.07	10.33bc	38.39
9	High	14	1672	2220	1.328	1673	91.0	25.6bc	22.84	10.19bc	39.49
10	High	12	1672	2155	1.292	1738	90.7	26.1b	22.77	11.28b	40.24
11	High	7	1683	2179	1.295	1723	90.1	26.1b	22.48	11.33ab	40.36
12	High	4	1654	2113	1.279	1623	90.7	24.4d	22.56	8.25cd	38.96
		SEM	39.73	62.74	0.0208	44.4	0.26	0.38	0.341	0.574	0.519
Main effect: Nutrient density
Low			1511c	2314a	1.533a	1525c	89.8b	25.8	22.59	10.51	39.19
Medium			1593b	2212b	1.389b	1613b	90.0b	25.6	22.63	10.13	39.21
High			1670a	2167b	1.298c	1689a	90.6a	25.6	22.66	10.26	39.76
Starch:lipid ratios
14			1658a	2343a	1.414	1675a	90.6a	26.2	22.79	11.17	39.41
12			1610a	2251ab	1.402	1638a	90.0b	25.4	22.81	10.11	39.84
7			1599a	2232b	1.400	1618a	90.1b	25.7	22.54	10.31	39.35
4			1498b	2098c	1.411	1505b	89.9b	25.3	22.37	9.61	38.94
P-value
Nutrient density			<0.001	<0.001	<0.0001	<0.0001	0.001	0.580	0.952	0.645	0.224
Starch:lipid ratio			<0.0001	0.007	0.794	<0.001	0.013	0.032	0.342	0.018	0.230
Interactions			0.074	0.406	0.609	0.175	0.083	0.002	0.918	<0.001	0.181

^abcd Means within a column not sharing common superscripts are significantly different

¹Lipid concentration in carcass was calculated from equation developed in the Poultry Research Foundation, University of Sydney: (3.9683×GE-75.622) × Dry matter