Effect of Induced Triploidy on Improvement of Flesh Quality Indices in All Female Rainbow Trout Oncorhynchus mykiss in the Second Year of Culture

Induction of triploidy in many all female fishes has economic application as it leads to increased growth and better flesh quality. Decrease or suppression of gonad development which is the result of fish sterilization and absence of secretion of sexual hormones causes positive effects on flesh quality indices. In the present study, flesh quality of all female triploid and diploid rainbow trout were compared by determining amounts of moisture, dry matter, total fat, protein, ash and energy using standard method of AOAC. In addition, viscera somatic index was determined. The results revealed that flesh proximate analyses of all female triploids were different compared to maturing diploid fish in the last months leading to sexual maturity in the second year of culture that is related to undeveloped gonads. At the end of sampling period, amount of moisture was significantly lower in triploids, but protein, lipid, energy, ash and dry matter were significantly lower in diploids due to their consumption for maturation (P>0.05). In conclusion, culture of al female triploid rainbow trout could be recommended for fish culturists who wish to continue the fish culture operations over maturation age and supply bigger fish to the market. Moreover, flesh total lipid and protein are retained as they are not utilized for maturation and therefore stable flesh quality could be ensured.