Muscle fibers and cellular characteristics of male Saanen kids with different slaughter weights

Abstract

Background: Fiber and cellular characteristics of skeletal muscle mass are directly related to growth in farm animals. Therefore, this study aimed to examine the DNA, RNA, and protein contents, as well as the number, size and diameter of muscle fibers in selected skeletal muscles of male Saanen kids with different post-fattening weights. Twenty-four male kids of the Turkish Saanen breed were individually fattened for 60 days after five months of weaning under an intensive management system. The kids were divided into two groups: low-slaughter-weight (n = 11; 27.73 ± 0.40 kg) and high-slaughter-weight (n = 13; 31.18 ± 0.23 kg) at the end of the fattening. Muscle samples from the central part of the mid-section of LD and ST muscles were excised from the right side of the carcasses. DNA, RNA, and protein content of muscle samples were isolated by commercial purification kits as suggested by the manufacturer. The total number and area of muscle fibers were determined using hematoxylin and eosin histological staining. Results: Kids with high-slaughter-weight had a higher (p < 0.05) number of total muscle fibers number in ST muscle than those of low-slaughter-weights. In contrast to muscle fiber cross-sectional area of low-slaughter-weight kids was higher (p < 0.05) than high-slaughter-weight kids in both muscles. Moreover, low-slaughter-weight kids had higher (p < 0.05) muscle fiber diameter than high-slaughter-weight kids in ST muscle. Kids with high-slaughter-weight had significantly higher (p < 0.05) contents of DNA and RNA in ST muscle but not in LD muscle compared to low-slaughter-weight kids. Also, high-slaughter-weight kids had significantly higher (p < 0.05) RNA: DNA in ST muscle. However protein: DNA, and protein: RNA ratios in ST muscle of low-slaughter-weight kids were significantly higher (p < 0.05) than those of high-slaughter-weights. Conclusions: This study demonstrates that the cellular and morphological mechanisms influencing the slaughter weight of male Saanen kids can be used to select more efficient animals for fattening practices.