How many muscle samples are required to obtain reliable estimations of muscle fibre characteristics from pig longissimus muscle?

In order to investigate the reliability of muscle fibre trait estimations of pig longissimus muscle and to derive the minimum number of samples required per muscle cross-section and animal, intraclass correlation coefficients (ICC, ϑˆ) were obtained by one-way analysis of variance. From each of 23 market weight pigs five samples, evenly distributed over the muscle cross-sectional area at the 12th/13th rib level, were taken and analyzed for various muscle fibre traits. The number of samples required per muscle cross-section was found to be different between selected fibre traits, ranging from a minimum of three (for number of muscle fibres) to a maximum of five or more (for mean fibre area, fibre type composition and relative area occupied by each fibre type). These findings should be taken as a recommendation, but their usefulness will depend upon the goal and conditions of future experiments.