Correlation of body weight gain with food and water consumption and spontaneous activity in rats.

We developed a data acquisition system which measure the body weight, food and water consumption and spontaneous activity of a rat automatically. The correlation of body weight gain with other parameters obtained by this system were analysed. Each parameter showed rhythmic circadian changes. The multiple regression analysis with stepwise method brought the high coefficiency on the body weight gain with water consumption in the dark period, whereas only low correlation was observed among the body weight gain, food consumption and spontaneous activity in the light period. Since the body weight is affected by various factors, food and water consumption, spontaneous activity and/or other parameter(s) with body weight should be monitored simultaneously.