A Comparative Study on the Adipogenic and Myogenic Capacity of Muscle Satellite Cells, and Meat Quality Characteristics between Hanwoo and Vietnamese Yellow Steers

Abstract

Myogenesis and adipogenesis are the important processes determining the muscle growth and fat accumulation livestock, which ultimately affecting their meat quality. Hanwoo is a popular breed and its meat has been exported to other countries. The objective of this study was to compare the myogenesis and adipogenesis properties in satellite cells, and meat quality between Hanwoo and Vietnamese yellow cattle (VYC). Same 28-months old Hanwoo (body weight: 728±45 kg) and VYC (body weight: 285±36 kg) steers (n=10 per breed) were used. Immediately after slaughter, tissue samples were collected from longissimus lumborum (LL) muscles for satellite cells isolation and assays. After 24 h post-mortem, LL muscles from left carcass sides were collected for meat quality analysis. Under the same in vitro culture condition, the proliferation rate was higher in Hanwoo compared to VYC (p<0.05). Fusion index was almost 3 times greater in Hanwoo (42.17%), compared with VYC (14.93%; p<0.05). The expressions of myogenesis (myogenic factor 5, myogenic differentiation 1, myogenin, and myogenic factor 6)- and adipogenesis (peroxisome proliferator-activated receptor gamma)-regulating genes, and triglyceride content were higher in Hanwoo, compared with VYC (p<0.05). Hanwoo beef had a higher intramuscular fat and total monounsaturated fatty acids contents than VYC beef (p<0.05). Whilst, VYC meat had a higher CIE a* and total polyunsaturated fatty acids content (p<0.05). Overall, there was a significant difference in the in vitro culture characteristics and genes expression of satellite cells, and meat quality between the Hanwoo and VYC.

Keywords: adipogenesis; fat; meat quality; myogenesis; satellite cell.

Fig. 1.. CCK-8 absorbance values recorded at 450 nm and plotted against their counterparts in directly counted cells.

Hanwoo (A) and Vietnamese yellow cattle (VYC) (B) satellite cells. (C) Number of satellite cells from Hanwoo and Vietname yellow cattle after 24, 48, and 72 h incubation in growth medium. The number of cells was calculated using the calibration curve that was made from the known number of cells. ^a,b Different letters within each incubation time indicate significant difference at p<0.05.

Fig. 2.. The differentiation of myoblast into multinucleated myotubes.

The morphology of Hanwoo (A) and Vietnamese yellow cattle (VYC) (B) myoblasts at initial culture with growth medium after 48 h isolation. The morphology of Hanwoo (C) and Vietnamese yellow cattle (D) myoblasts after 72 h proliferation. Staining of myotubes after 4-day myogenic differentiation from Hanwoo (E) and Vietnamese yellow cattle (F) for Hematoxylin and Eosin. The cells were observed under light microscope at 40× magnification. (G) The fusion index (ratio of multinucleated cells to total number of nuclei counted) of satellite cells from Hanwoo and Vietnamese yellow cattle. ^a,b Different letters indicate significant difference at p<0.05.

Fig. 3.. mRNA expression of MYF5 and MYOD1 during proliferation, and MYOG and MRF4 genes expression during differentiation in satellite cells isolated from Hanwoo and Vietnamese yellow cattle (VYC).

Data was expressed as fold expression normalized to the housekeeping gene (GAPDH). ^a,b Different letters indicate significant difference at p<0.05. MYF5, myogenic factor 5; MYOD1, myogenic differentiation 1; MYOG, myogenin; MRF4, myogenic factor 6; GAPDH, glyceraldehyde-3-phosphate dehydrogenase.

Fig. 4.. Adipogenic differentiation ability of satellite cells isolated from Hanwoo and Vietnamese yellow cattle (VYC).

(A) Concentration of triglyceride content in the Hanwoo and VYC muscle satellite cells after 5 and 7 days of induction with adipogenic differentiation medium. (B) mRNA expression of adipogenic regulatory factor (PPARγ) during the adipogenic differentiation. Data was expressed as fold expression normalized to the housekeeping gene (GAPDH). ^a,b Different letters indicate significant difference at p<0.05. PPARγ, peroxisome proliferator-activated receptor gamma; GAPDH, glyceraldehyde-3-phosphate dehydrogenase.

Fig. 5.. Principle component analysis for the myogenic and adipogenic properties of skeletal muscle satellite cells, and meat quality traits of longissimus lumborum muscles from Vietnamese yellow cattle (VYC) and Hanwoo.

PC, principle component; PUFA, polyunsaturated fatty acid; SFA, saturated fatty acid; MUFA, monounsaturated fatty acid; PPARγ, peroxisome proliferator-activated receptor gamma; MYOG, myogenin; MYF5, myogenic factor 5; IMF, intramuscular fat; MRF4, myogenic factor 6; USFA, unsaturated fatty acid; MYOD1, myogenic differentiation 1.