Effect of Different Protein Source Diets on Growth, Sensory Parameters and Flesh texture of On-Growing Grass Carp (Ctenopharyngodon idellus)

The introduction of plant protein (PP) sources in aquafeed is regarded as an economic and environmental-friendly strategy for aquaculture. Our objective was to investigate the effects of pure PP diets on the growth performance and to analyze their effects on flesh quality of grass carp (357.2 +/- 0.7g). The study was performed using and comparing a control fish meal diet and two PP diets. Fish meal (FM), soybean meal (SBM), and rapeseed meal (RM) were served as sole protein source of corresponding feeds, respectively. The results suggested that the PP diets significantly impaired the growth performance of grass carp. In regard to flesh quality, the SBM and RM diets decreased the muscle lipid content, n-3 series of PUFA, EPA, DHA, and n-3/n-6 ratio at the nutritional level. However, from the consumer's perspective SBM significantly improved flesh firmness, and RM diets, and PP diets had no adverse effects on flesh flavor, amino acids composition, and sensory characteristics. Fish fed the RM diet displayed a higher water holding capacity (WHC) in the fillets than in the other groups. In summary, compared to the FM diet, both SBM and RM diets reduced fish growth and flesh lipid nutritive values, but improved the fillet firmness. Plant ingredient-rich diets do not have detrimental effects on muscle flavor because of the free amino acids composition and organoleptic attributes.