Morphological characteristics and chemical composition of muscle in the mirror carp ( Cyprinus carpio var. specularis) as influenced by body weight

Abstract

The evolution of morphological traits and muscle chemical composition during growth was analysed by allometric or normal regression (on body weight or total length or total lipid) utilizing a preliminary series of data obtained from mirror carps ranging from 39 to 2776 g body weight. The fish came from earthen ponds fed with warm water (refluent from a thermal power station) at about 10 °C above natural temperature. As regards allometric coefficients of components on body weight, gills (0.70) and filleting remnants (0.85) were the earliest growing while viscera (1.18) and skin (1.11) were the latest. Isoauxesis resulted for fins, excluding pelvic fins that were later growing (1.08). As regards relative growth of lengths and thicknesses on total body length, head length (0.82) was the earliest and abdomen (1.15) and trunk lengths (1.12) were the latest growing; all body thicknesses showed tachyauxesis, particularly on the hind-portions. As regards the chemical composition of muscle, cholesterol (mg/100 g) and the C20:4 and C22:6 percentages showed a linear decreasing trend with increasing body weight, while the opposite resulted for C18:1, SFA and MUFA content. Lipid, C16, C16:1, C20:5 and n − 3 PUFA content presented a decreasing trend followed by an increase, while C18:2 and n − 6 PUFA content showed the opposite behaviour. Intramuscular lipid content influenced the chemical composition of muscle: as lipid content increased, C18:1 also increased, while C18:2 and n − 3 PUFA decreased; C14, C16:1 and MUFA showed an increasing trend followed by a decreasing phase, while C16, C18, C20:4, C22:6, SFA and n − 6 PUFA showed the opposite.