Postslaughter state of muscle tissue of pigs depending on the duration of pre-slaughter fasting

Abstract

Changes in the muscle tissue microstructure lead to changes in meat quality. One of the causes of the myopathy development is animal stress. Pigs experience the strongest stress during pre-slaughter holding. The study of the postmortem meat structure depending on fasting time is a topical task. The objects of the research were samples of m. L. dorsi obtained after slaughter from pigs that differed in fasting time: 4 (group 1), 8 (group 2), 10 (group 3), 16 (group 4) and 18 (group 5) hours (N = 20, n = 4). Investigation of the microstructure and morphometric measurements were carried out on preparations stained with hematoxylin and eosin. Myopathic changes in muscle tissue were assessed using a semi-quantitative method developed earlier. All studied samples were characterized by the uniform condition of muscle tissue. Statistically significant differences between individual groups were observed regarding the number and area of giant fibers, sarcomere length, diameter of muscle fibers and proportion of muscle fibers, which diameter was lower or higher by 1/3 than the mean fiber diameter. An increase in the pre-slaughter holding time reduced the number and area of giant fibers (r = –0.8437 and –0.5796, respectively), as well as the diameter of “normal” fibers (r = –0.5337), which positively influenced pork quality. Groups 1, 2 and 3 were characterized by the presence of signs of moderate and pronounced myopathy. Only one carcass with pronounced myopathic signs was revealed in each of groups 4 and 5. In group 4, one carcass did not have signs of myopathy. Pre-slaughter holding during 4, 8 and 10 hours led to deterioration of pork quality. The recommended fasting time is 16 hours.

Comparative Study on the Postmortem Proteolysis and Shear Force during Aging of Pork and Beef Semitendinosus Muscles

“…According to Bhat (2018), a high proteolytic enzyme activity, low collagen content, and long sarcomere length are required for high tenderness. In previous studies comparing the collagen content of the semimembranosus muscle in pork and beef, the collagen content in pork was reported to be 4.13 and 5.30 mg/g, while the collagen content in beef was reported to be 6.85 mg/g (Seong et al, 2009;Semenova et al, 2023;Moon et al, 2006). Additionally, in a study comparing the length of sarcomeres, the reported sarcomere lengths of pork and beef were 2.50 μm and 1.89 μm, respectively (Moon et al, 2006).…”

“…These differences might be attributed to differences in the fiber compositions of the pork and beef semitendinosus muscles. Considering the muscle fiber composition of the semitendinosus muscle, red and white muscle fibers constitute 10-20% and 64-80% of pork, respectively (Semenova et al, 2023), whereas beef contains 10-30% and 34-58%, respectively (Totland et al, 1988). White muscle fibers are known to have a lower water-holding capacity than red muscle fibers because of their strong glycolytic activity, resulting in the exudation of more water (Kim et al, 2013;Lyu et al, 2024).…”

Histological characteristics and functional properties of red and white parts of <i>m. semitendinosus</i> of slaughter pigs

“…In the Russian Federation, fast growing hybrid animals from three-breed crossing (LWxDxL) are mainly used for growing pigs for slaughter [7]. Earlier, we studied manifestation of myopathic changes, which are typical of PSE meat and emerge under an effect of lifetime and slaughter factors, in the microstructure of m. longissimus dorsi taken from slaughtered hybrid animals [8,9]. This muscle is the most frequently chosen object of investigations and its characteristics are studied quite well.…”