Effect of Sex and Muscle on the Fiber-Type Composition and Cross-Sectional Area of Springbok (Antidorcas marsupialis) Muscle

Abstract

This study aimed to compare the fiber-type composition and fiber cross-sectional area (CSA) of male and female springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscles. Frozen samples from 4 male and 3 female springbok were fiber-typed immunohistochemically using the primary antibodies A4.74, BA-D5 and BF-35. The CSA of the fibers was determined using the software Image J. Type IIX fibers accounted for 64 to 77% of the fibers in all samples, with type IIA (12.7 to 19.1%), type IIAX (6.4 to 9.3%) and type I (2.4 to 8.5%) making smaller (P < 0.001) contributions. Female springboks’ muscles contained more type IIX fibers than males’ (P = 0.004) and the BF contained more type I fibers and fewer type IIA and IIAX fibers than the LTL (P < 0.001). CSA values did not differ between sexes or muscles; however, they increased with apparent fiber glycolytic capacity (I < IIA < IIAX < IIX; P < 0.001). The glycolytic nature suggested by the fiber-type composition of springbok muscle found in this study is in contrast with previous reports on the physicochemical nature of springbok meat. This casts doubt on the application of standard associations between fiber-type and meat quality to this species. However, it may provide some explanation for the low shear force values found for springbok meat in previous studies.