Calorimetric studies on selected lines of Japanese quail

Abstract

Calorimetric measurements were made on groups of Japanese quail selected for increased body weight at either 20 or 35 days on either a high- or low-nutrient density diet. For the majority of biological parameters measured, the selected lines outperformed the unselected controls. Weight gain, metabolizable energy (ME) intake, food conversion efficiency, and energy retention were greater for the selected than for the control line. The major difference between the two groups was the higher mean food consumption of the selected lines. Quail selected at 35 days on the high nutrient density diet ate more food, gained more weight and retained more energy and body fat than those selected at the same age on the low nutrient density diet. Net availability of ME for growth was the same (0.69) for the selected and unselected lines; it was 0.66 for protein deposition and 0.83 for fat deposition. Maintenance energy requirement for eight quail was 1.2 MJ ME (kg wt)-1 day-1. Retention of dietary nitrogen was 0.61 of nitrogen intake. There was no difference between the lines in starvation heat production. However, birds fed ad libitum prior to starvation had a 12% higher heat production than those restricted to 70% of ad libitum feed.