Conventional vs. slow-growing broilers: developmental pathways associated with differential muscle and adipose growth.

Genetic selection of conventional broiler chickens has created a modern-day broiler that is characterized by rapid growth and high feed efficiency. This rapid growth has allowed chicken to be the most readily available and most consumed meat in the United States. However, the selection for rapid growth has led to an increase in unintended consequences that diminish meat quality and decrease welfare status. The rise of these consequences has put pressure on the broiler industry to create production practices and genetic lines that support slow growth. These slow-growing lines provide the opportunity to study lines that are differentially selected growth as a means of better understanding pathways that underlie early life development of muscle and adipose tissue. To accomplish this, eggs from the conventional Cobb 500 and the slow-growing Redbro broiler lines were incubated until hatch and raised to 14 days with samples of the breast muscle (BM), the subcutaneous (SQ), abdominal (ABD), and neck (Neck) fat pads, and the cecum being collected to determine phenotypic, genetic, and microbiome differences that may be contributing to differences in growth. The results of this study reveal differences in phenotypic characteristics such as tissue weight, adipocyte size, fatty acid composition of adipose depots, differential gene expression, and bacterial microbiome differences that may be accounting for differences in growth.