Effect of dietary supplementation with n-3 series essential fatty acids on quality of egg, embryo and larvae in rainbow trout (Oncorhynchus mykiss W., 1792) reproduction

In this study, the effect of dietary supplementation with n-3 series essential fatty acids (linoleic acid, stearidonic acid, eikosapentaenoic acid, dokosapentaenoic acid and dokosahexaenoic acid) on quality of egg (egg diameter, total weight of non hardened eggs, total weight of after hardened eggs, weight increase of egg during water hardening, contents of fatty acids, and protein in egg), embryo (fertilization rate of egg, eyed stage rate of egg, eyed stage time, hatching rate, hatching time, contents of fatty acids and protein in embryo) and larvae (survival rate of larvae, weight and length of larvae, width yolk sac, length yolk sac, starvation time of larvae, contents of fatty acids and protein in larvae) in rainbow trout (Oncorhynchus mykiss) reproduction were investigated.In addition, the growth of adult fish (live weight gain, relative growth rate and condition factor), feed utilization (feed intake, feed conversion ratio, protein efficiency ratio and protein productive value), gonadosomatic index, hepatosomatic index and vicerosomatic index, number of eggs per fish, number of eggs per kg of fish, chemical quality (contents of fatty acids, crude fat and protein) in meat and liver of fish were investigated too.For this purpose, experimental diets control, 1, 2 and 3 were prepared at the n-3 series essential fatty acids ratios 1.18%, 0.20%, 2.20% and 3.19%, respectively. Crude protein and total energy levels of control and test rations were equalized. Three replicates were conducted for each trials. Feeding rate was calculated as the feeding coefficient and percentage of the live weight was given to fishes three times in a day during 45 days at 10±1 oC of water temperature.At the end of this study, the best results for these parameters were obtained from 3 numbered experimental group that was followed by test group 2 and control group, respectively. Lowest results were obtained from 1 numbered experimental group that was not added n-3 series essential fatty acids. It was determined significant (p<0.05) differences between Control and experimental groups in the feed intake, feed conversion ratio, protein efficiency ratio, hepatosomatic index, eyed stage time, width yolk sac, starvation time of larvae, total levels of n-3 series essential fatty acids in eyed egg, fry fish meat, liver and whole body meat of adult fish after experiment, and crude protein levels in meat of larvae and fry fish (except for egg diameter, fertilization rate of egg, hatching rate in fertilized egg, contents of crude protein, fat, fiber, moisture and total energy in whole body meat of adult fish after experiment, p>0.05).However, there was not determined a significant differences between 2 and 3 numbered experimental groups in the live weight gain, relative growth rate, protein efficiency ratio, vicerosomatic index, gonadosomatic index, number of eggs per fish, number of eggs per kg of fish, egg diameter, total weight of non hardened eggs, weight increase of egg during water hardening, fertilization rate of egg, eyed stage rate of egg, hatching rate, hatching time, numbered of larvae, weight and length of larvae, survival rate of larvae, total levels of n-3 series essential fatty acids in fertilized egg and larvae, crude protein levels in fertilized egg and eyed egg (p>0.05).Under the light of this study, it is concluded that the diet of adult rainbow trout has to constitute 2.20% of n-3 series essential fatty acids for generating high number and quality of egg, embryo, larvae and therefore fry fish.Keywords: Rainbow Trout, Oncorhynchus mykiss, n-3 Series Essential Fatty Acids Reproduction, Quality, Egg, Embryo, Larvae, Fry.