THE EFFECTS OF PRE-HARVEST RESTRICTED FEEDING ON THE GROWTH AND THE PRODUCT QUALITY TRAITS OF POND-REARED GIBEL CARP (CARASSIUS AURATUS GIBELIO)

One-month growth trial was conducted to investigate the effects of different feeding regimes prior to slaughter on the growth and the product quality of pond-reared gibel carp. Five feeding levels were approached: satiation (R100), 80% of satiation (R80), 60% of satiation (R60), 40% of satiation (R40), and unfed (R0). The results showed that the specific growth rate (SGR) of gibel carp decreased significantly at the feeding level of 60%. In the contrast, an improved gutted yield was observed at R40 and R0. The unfed fish exhibited a leaner body shape and a harder muscle mass compared to the control group. The lipid content and the total collagen content potentially contribute to muscle textural traits. Analysis on these two factors showed that the lipid content of the muscle reduced significantly whereas there was no difference in the total collagen content. The restricted feeding regime resulted in reduced fat contents in different parts of fish body, especially in the visceral. Relationships between SGR and the lipid content were established using a liner regression model, in which SGR accounted 56% for the dorsal muscle lipid, 66% for the ventral muscle lipid, and 71% for the visceral lipid in the total variation. Both the crude protein content and the ratio of essential amino acid to non-essential amino acid were stable in fish at different feeding levels, indicating that the restricted feeding regime did not affect the muscle protein quality in terms of the nutritional value.