Characterizing muscle growth and quality traits of sheep having the callipyge phenotype using a muscle cell culture system

Expression of the callipyge gene causes a sharp increase in muscle mass and a severe decrease in tenderness of the longissimus muscle. The objective of this dissertation is to characterize protein turnover as it relates to muscle growth and correlate protein turnover to the tenderness of the longissimus muscle in callipyge sheep.

In two experiments, 18 callipyge and 18 normal Rambouillet cross sheep were slaughtered and fabricated at the Meat Lab at Texas Tech University. After 24 h postmortem, hot carcass weight, longissimus area, fat thickness, marbling, flank streaking, leg score, and lean color, texture, and firmness scores were recorded. In addition samples for calpastatin activity myofibrillar fragmentation index (MFI), muscle extract were collected at this time. After 14 d of aging, boneless loin chops were removed from the carcass for Warner-Bratzler shear (WBS) and trained sensory panel evaluations.