Fat Deposition in the Muscle of Female and Male Yak and the Correlation of Yak Meat Quality with Fat.

Ping Yan,Xian Guo,Jie Pei,Lin Xiong,Min Chu,Xiaoyun Wu,Qudratullah Kalwar

doi:10.3390/ani11072142

Abstract

Simple SummaryThe type and quantity of fat are among the key factors influencing the carcass and meat quality in yak. The effect of gender to fat in yak and the correlation of meat quality with fat were studied in this paper. The meat of male yaks (MYs) is healthier from the point of nutritional value, whereas the meat of female yaks (FYs) possesses better qualities in relation to the visual impact and mouthfeel. The below results can provide a theoretical basis for the deep processing of yak meat. Yak meat quality (especially tenderness) can be improved by increasing the content of fat, C18:0, cis-C18:2, and cis-C18:1 in muscle during yak production. These genes, including SCD, PLIN5, LPL, ME1 and DBI, play a crucial role in the regulation of fat deposition in yak. Above candidate genes for fat deposition in yak can supply the theoretical basis in molecular breeding of yak with a high fat content in muscle.This study aimed to explore the differences in fat deposition between female (FYs) and male yaks (MYs). Compared with MYs, the tenderness, L*, marbling, absolute content of fat, and most fatty acids (FAs) of longissimus dorsi (LD) in FYs were higher or better (p < 0.05), whereas the relative content of polyunsaturated fatty acids (PUFAs) and n-3 PUFAs were lower (p < 0.01). The absolute content of fat, C18:0, cis-C18:2, cis-C18:1, and C24:0 were positively correlated with L*45 min, b*24 h, tenderness, and marbling score of LD in FYs and MYs (p < 0.05), respectively. LPL, FATP2, ELOVL6, HADH, HACD, and PLINS genes play a crucial role in improving the marbling score and tenderness of yak meat. The results of gene expression and protein synthesis showed the effect of gender to FA biosynthesis, FA transport, lipolysis, and FA oxidation in the adipose tissue of yak was realized by the expressions of ME1, SCD, ACSL5, LPL, FABP1, PLIN4, and PLIN2 in peroxisome proliferators-activated receptor (PPAR) signaling. This study established a theoretical basis for the improvement of the meat quality of yak and molecular breeding.

Highlights

These results showed that the degradation of long-chain polyunsaturated fatty acids (PUFAs) may contribute to the increase in short-chain saturated fatty acids (SFAs) [34]
The fatty acids (FAs) composition in male yaks (MYs) meat is healthier for consumers, whereas the tenderness, L*, and marbling score of longissimus dorsi (LD) of female yaks (FYs) are better from the viewpoint of vision
Positive correlations were found between fat content and L*24 h, marbling, whereas negative correlations were found between fat contents and shear forces; the absolute contents of C18:0, cis-C18:2, cis-C18:1 and C24:0 were positively correlated with L*45 min, b*24 h, marbling score, respectively

Summary

Introduction

Along with the rapid development of globalization and the change of consumer philosophy, the demand, supply, and acceptance of unconventional and exotic meats are increasing around the world [8,9,10,11]. Yak meat is a unconventional meat, and the major source of animal protein in the local human diet [14,15]. Because of its rich protein and low fat, devoid of anabolic steroids and pollutants, yak meat is increasingly popular with consumers [16]. The annual yak meat yield is more than 500 thousand tons. The carcass yield and dressing percentage of yak are 46.67–51.0% and 37.10–43.02%, respectively. The yak industry is an extensive management and low production performance

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