Comparison of muscle fiber characteristics and glycolytic potential between slow- and fast-growing broilers

Abstract

Muscle fiber characteristics had beneficial effects on meat masses and meat quality in broilers. Its number is determined at birth and directly affects the growth and development of muscle fibers after birth. However, whether the muscle fiber characteristics in different types of chickens are different at birth has not been fully documented. In this study, the 1-day-old Xueshan chicken (slow-growing broiler) and Ross 308 broiler (fast-growing broiler) were selected, respectively, and the fiber type distribution, fiber density, and fiber size in the breast (pectoralis major, PM) and leg (gastrocnemius, GAS) muscles were detected. The results showed that the PM only made up of type IIB fibers regardless of breed, and that few type I fibers (approximately 17.55%) was identified in GAS of Ross 308 broiler. The PM muscles had significantly higher fiber density, lower cross-sectional area and diameter than those of GAS muscles in both 2 breeds (P < 0.05). The highest fiber density was observed in PM of Xueshan chicken. Furthermore, the muscle fiber characteristics were partly controlled by glycolytic potential (GP), and the GP was also invesgated. The GP in PM and GAS of Ross 308 broiler were higher than in Xueshan chicken (P < 0.05). Taken together, 1-day-old Xueshan chicken exhibited higher fiber density and lower GP compared to 1-day-old Ross 308 broiler, especially in PM, which could not only reveal the differences of muscle characteristics among different types of chickens, but also explore a new way to improve the masses and quality of poultry meat.

Keywords: fast-growing broiler; glycolytic potential; muscle fiber characteristic; slow-growing broiler.

Figure 1

Relative mRNA expression of myosin heavy chain (MyHC) isoform genes in the m. pectoralis major (PM) and m.gastrocnemius (GAS) from one-day-old Ross 308 and Xueshan chicken. The given values are reported as means ± standard error (n = 6). Statistically significant differences are indicated by different letters (P < 0.05).

Figure 2

Transverse sections of m. pectoralis major (PM), and m. gastrocnemius (GAS) stained with two monoclonal antibodies against specific myosin heavy chain (MyHC) isoforms. Red arrows point to examples of fibers with positive immunostaining for type IIB fibers; Green arrows point to examples of fibers with positive immunostaining for type I fibers. Magnification of 800 × was used (Bar = 20 μm).

Figure 3

Glycolytic potential in m. pectoralis major (PM) and m. gastrocnemius (GAS) from Ross 308 and Xueshan chicken. (A–D) The content of glycogen (A), glucose (B), glucose 6 phosphate (C), and lactic acid (D). (E): Glycolytic potential. ^a-c Means ± standard error (n = 6) with different superscripts are significantly different (P < 0.05).

Figure 4

Hematoxylin and eosin staining in m. pectoralis major (PM) and m. gastrocnemius (GAS) from Ross 308 and Xueshan chicken. Magnification of 800 × was used (Bar = 20 μm).