Influence of protein/energy ratio on carcass quality during the growing period of Eurasian perch (Perca fluviatilis)

摘要

An experiment was performed to study the effects of three protein/energy ratios (A=25, B = 22 x 10(-3) and C = 19 x 10(-3) mg kJ(-1)) on zootechnical (growth, feed intake, feed efficiency and survival), technological (heterogeneity, gutting and filleting yield), flesh quality (composition, texture and flavour) and environmental (nitrogen pollution) parameters relative to Eurasian perch. The experiment was carried out in triplicate (85 fish) during an 18-week period, from 35 g to commercial size (150 g). The fish were fed by hand twice a day to satiation and the daily feed intake was recorded. During the last period (week 12 to week 18), growth was significantly higher (P<0.05) in the group fed diet B. Feed efficiency and protein efficiency rates were improved (P<0.05) as protein/energy ratio decreased. Based on eviscerated weight, feed efficiency was similar for fish fed diets B and C. The viscerosomatic index increased as the protein/energy ratio decreased (P<0.05). The highest gutting and filleting yield was obtained for fish fed diet A. The lipid content variations in the flesh were limited. No relation was observed between the biochemical and organoleptic characteristics of the flesh and dietary treatment. High-energy feed led to a reduction of nitrogen compound excretions (P < 0.05).