Growth and meat quality relations in carp

Abstract

Growth proceeds through an harmonious development of major tissues, namely bone, muscle and adipose tissues. Changes in chemical composition result from differential growth of these tissues. Little is known about the relative changes in morphometric traits during development of carp or about their genetic basis, but it seems that valuable criteria for selection on suitability for processing could be found in the mechanisms of bone and muscle development. The development of fatty tissues associated with growth of carp is stimulated by the use of lipid-enriched or high-energy artificial diets. Fat is accumulated in specific adipose tissues and the analysis of the relative development of these tissues could give valuable information on the over-accumulation of fat and its distribution in the whole body. Accumulation of fat has either positive or negative consequences for sensory evaluation depending on the source and the composition of fat. The main characteristics of muscle and connective tissues are presented in this paper. Different muscle tissues comprising different fibre types are found in cyprinids. These tissues together with adipose tissues compose the edible part of carp and explain most of protein retention. Protein content and composition are stable during development. Furthermore, a wide variability in the characteristics of muscle and connective tissues persists in commercial-size fish related to their mode of development. It is especially true for the main contractile protein: myosin. This is illustrated on expression of isoform of myosin but in early stages. The changes in the characteristics of the tissues and of the flesh after death and during postmortem storage and processing are reviewed. The structural components and the organization of tissues are very specific in fish and more sensitive to destruction. Thus, the degradative processes that affect the flesh during storage and processing have important consequences for sensory evaluation of the flesh which in freshwater species is generally rather soft and with neutral odour and taste. In this paper the possible role of biological characteristics of the flesh and of its constitutive tissues in quality is analyzed for the effect of body weight and for the effect of acclimation temperature. Temperature induces specific compensation for the maintenance of basic processes and the consequences for quality are analysed as well.