The IGF-1/Akt/S6 Signaling Pathway is Age-Dependently Downregulated in the Chicken Breast Muscle.

The skeletal muscle mass is known to be controlled by the balance between protein synthesis and degradation. The fractional rate of protein synthesis has been reported to decrease age-dependently from 1 to 4 weeks of age in the chicken breast muscle (pectoralis major muscle). On the other hand, age-dependent change of the fractional protein degradation rate was reported to be less in the skeletal muscle of chickens.

Differential regulation of the expression of lipid metabolism-related genes with skeletal muscle type in growing chickens.

The regulatory mechanisms of carbohydrate and lipid metabolism are known to differ among skeletal muscle types in mammals. For example, glycolytic muscles prefer glucose as an energy source, whereas oxidative muscles prefer fatty acids (FA). We herein demonstrated differences in the expression of genes involved in carbohydrate and lipid metabolism in the pectoralis major (a glycolytic twitch muscle), adductor superficialis (an oxidative twitch muscle), and adductor profound (a tonic muscle) of 14-day-old chicks.

Differences in the expression of genes involved in skeletal muscle proteolysis between broiler and layer chicks during food deprivation.

Genetic selection results in a higher growth rate and meat yield in broiler chickens than in layer chickens. We herein demonstrated differences in the effects of 24 h of fasting on the expression of genes involved in skeletal muscle proteolysis between broiler and layer chicks. The mRNA levels of proteolysis-related genes were analyzed in the pectoralis major muscle of 14-day-old chicks after 0 or 24 h of fasting.

Dietary mannanase-hydrolyzed copra meal improves growth and increases muscle weights in growing broiler chickens.

The utilization of copra meal as a feed ingredient is limited because it contains a high level of mannan. However, recent findings indicate that the effect of copra meal on growth performance in broiler chickens can be improved by the supplementation of mannanase in the diet. In the present study, we examined the effect of mannanase-hydrolyzed copra meal (MCM) on growth performance and muscle protein metabolism in growing broiler chickens (Gallus gallus domesticus).