Effect of season on contractile and metabolic properties of desert camel muscle (Camelus dromedarius)

Abstract

Thirty fattened one humped desert camels were used to examine the effect of season on contractile and metabolic properties of Longissimus thoracis (LT) muscle. Ten camels were slaughtered according to seasons of the year (winter, summer and autumn). Season significantly influenced muscle chemical composition, ultimate pH (pHu) and color. Activities of metabolic enzymes were higher during autumn season compared to summer and winter for phosphofructokinase (+ 64% compared to both seasons) and for isocitrate dehydrogenase (+ 35% and + 145% in autumn vs. summer and winter, respectively). Quantification of muscle myosin heavy chain isoforms by SDS-PAGE electrophoresis showed only presence of type I and type IIa MyHC in camel muscle and indicated high proportion in winter for type I and in autumn for type IIa with respect to other seasons. Several correlations between different MyHC proportions and enzyme activities were reported. These findings indicated that muscle characteristics in camels are influenced by season.

Introduction

Camel is a unique animal having the ability to survive and produce with low cost of feeding under harsh conditions compared to other livestock. It is a good source of meat in areas where the climate adversely affects other animal's production efficiency (Kadim et al., 2006). Traditionally, camel meat comes mostly from old males and females that are primarily kept for milk, racing, and transportation rather than for meat production. General consumers' view is that camel meat is unacceptably tough, but in fact meat from young camels has been reported to be comparable in taste and texture to beef (Kurtu, 2004). Carcass characteristics of camels were equal to those of other red meat animal species (Elgasim & Alkanhal, 1992). Chemically camel muscles had been found to have low fat content, high water holding capacity recommending camel meat as a healthy food with good processing properties (Babiker & Yousif, 1990). However, there is evidence of a great demand for fresh camel meat and for camel meat in blended meat products even in societies not herding camels (Morton, 1984; Pérez et al., 2000).

Characteristics of camel and cattle meat as well as muscle fiber types had been studied by many authors (Costa et al., 2008, Kadim, Al-Hosni, et al., 2009, Kadim, Mahgoub, et al., 2009, Lefaucheur, 2010, Rose et al., 1992, Vestergaard et al., 2000). Different isoforms of Myosin Heavy Chain (MyHC) in bovine muscle were described: MyHC I, MyHC IIa and MyHC IIx (Picard, Duris, & Jurie, 1998). The MyHC IIb had been reported in some cattle from the Blonde d'Aquitaine French breed (Picard & Cassar-Malek, 2009). Muscle characteristics and meat quality have been known to be affected by growth and breed type (Renand, 1990), age and sex (Monin, 1990) as well as feeding level and diet composition (Geay, Bauchart, Hocquette, & Culioli, 2001). Klont, Brocks, and Eikelenboom (1998) noted that muscle metabolic and contractile types are adaptable and may be modified in living animals by environmental conditions and genetic selection. They indicated that in cattle, environmental effects were more important due to the large variations in production methods. To our knowledge, the effect of season on camel meat characteristics has not been reported. The present work aimed to investigate the effect of seasons on muscle characteristics of one humped desert camel (Camelus dromedarius).