The effect of cold stress on muscle growth in young chicks.

The effect of cold stress on muscle growth in young poultry stock has been examined during an experiment involving one hundred and eight chicks. They were divided into two groups, namely the control group and the cold stress group. The newly-hatched chicks of broiler type were chilled at a temperature of 10 degrees C for a total of four hours. The breast and thigh muscles of one side of each bird were analyzed for fat, protein, potassium, magnesium, calcium, and sodium during the two weeks after hatching. In the stressed chicks, body weight, breast and thigh muscle weight were consistently lower over the fortnight than in the controls. The body weight of the stressed birds was increased by two-fold, whereas, in the controls, the increase was there and a half times. The breast and thigh muscle weights of the stressed chicks increased by seven times and two times, respectively. In the normal birds breast and thigh muscle weights were enhanced fifteen times and four times, respectively. The protein content of the breast muscle in the normal birds was enhanced by thirty-fold and that of the thigh muscle by five-fold. In the stressed chicks the increase in the protein content in the breast muscle was twelve-fold and that of the thigh muscle was two-fold. Muscle fat content was lower in the chilled birds than in the controls. Levels of potassium and magnesium were also lower in the stressed chicks than in the normal birds.