Effect of the selection of high and low oxygen consumption on the feed conversion ratio in mice

Abstract

To create the line with a different maintenance energy requirement of the mouse, the selection of high (H line) and low (L line) oxygen consumption was done during the ninth generation. Selection trait was oxygen consumption per metabolic body size (O2C/MBW) until the sixth generation. The heritability estimates of body weight (BW), oxygen consumption (O2C), and O2C/MBW were about 0.500 in both H and L line. The genetic correlation of BW and O2C/MBW was -0.177 in H line and -0.345 in L line. The result showed that H line was significantly smaller in BW than L line as the correlated response. When the selection trait was changed into O2C and from the 7th generation to the 9th generation, no significant difference was observed in the BW of H and L lines, and phenotypic and estimated breeding values of O2C and O2C/MBW were significantly higher in H line than in L line on the 9th generation. One hundred sixty mice from both lines of 20 male and 20 female of the 8th and 9th generation were used for the comparison of feed conversion ratio (FCR). The L line was significantly lower in FCR from 4 to 7 week than the H line. This result suggested that the selection of high and low O2C is effective to create the lines of mice with different feed efficiency.