English abstract
Effect of three levels of feed (hay plus concentrate) at 1.5%, 2% or 2.5% of body weight feeding for seven months on carcass, meat quality and histochemistry of six muscles was studied in ten dromedary camels of 1-2 year of age. Six muscles: Infraspinatus, longissimus thoracis, triceps brachii, biceps femoris, semitendinosus and semimembranosus were dissected from each carcass and used for quality and histochemical evaluation. Carcass characteristics including carcass dimensions were recorded. Warner-Bratzler shear force, pH, sarcomer length, myofibrillar fragmentation index, expressed juice, cooking loss, L', a, 6* colour, moisture%, protein%, fat% and ash%, macro- and micro-elements of each muscle were measured. Fatty acid profile, saponification, iodine number and melting point of intramuscular fat of each muscle were also determined. The histochemical staining properties of the myosin ATPase and succinate dehydrogenase. The leg length and width behind shoulder of camel carcasses were significantly (P<0.05) affected by feeding treatment. Moisture%, protein% and fat% were significantly (P<0.01) different between six muscles. The semimembranosus muscle had the highest, while the longissimus thoracis had the lowest protein content. The feeding levels had no significant effect on muscle macro- and micro-elements. In general, muscles contained high potassium level followed by phosphorus, sodium, magnesium and calcium. Zinc and copper were significantly (P<0.001) different between muscles. The total fatty acids across the six muscles ranged between 19.2% (triceps brachii) to 59.7% (longissimus thoracis). Mono-unsaturated, poly-unsaturated fatty acids and ratio of saturated to total fatty acid were significantly affected by muscle. The treatment and type of muscle had a significant (P<0.05) effect on iodine number. There were significant (P<0.05) differences in the initial muscle pH (40 min post-mortem) between different muscles. The range of variation in overall expressed juice between the six muscles was 38.1 cm'lg in triceps brachii muscle to 41.9 cm g in semitendinosus muscle. Overall, longissimus thoracis muscle had the highest cooking loss (33.8%) and triceps brachii muscle had the lowest (28.9%). The Shear force values of semitendinosus, semimembranosus and biceps femoris were significantly higher than longissimus thoracis and infraspinatus muscles. Sarcomere length values ranged between 1.27um (semitendinosus) to 1.53um (semimembranosus). Longissimus thoracis muscle had significantly higher values for L*, a*, b* than semitendinosus. Semimembranosus muscle had the highest myofibrillar fragmentation index (61.8), while infraspinatus muscle had the lowest value (39.4). Semitendinosus muscle had significantly the highest proportion of Type I and the lowest proportion of Type IIA than other muscles, Feeding levels and muscles type had significant effects on muscle fiber diameter. This study indicated that management type had a minor effect on meat quality and histochemical of muscles from different locations. Variation between muscles may be due to different functional properties according to their locations.
