Effect of diets containing Celmanax prebiotic on fillet quality of Oncorhynchus mykiss during refrigerated storage

This study aimed to evaluate the fillet quality of rainbow trout, Oncorhynchus mykiss after feeding with different levels of Celmanax prebiotic. A total of 780 trout with an initial body weight of 18 ± 2 g were randomly distributed after adaptation to the experiment environment in tanks filled with 105 L spring water (65 fish per tank). Three experimental groups and control each with three replicates were considered. Trout were fed with diets containing 2 (T2), 4 (T4) and 6 (T6) g/kg prebiotic for eight weeks. Then, the fish were filleted and maintained in the refrigerator. The chemical parameters including TVB-N, PV, TBA, FFA, TVC and PTC were estimated in 0, 3, 6, 9, and 12 days of storage time. No significant differences were observed in experimental groups and control in free fatty acids content in fillet (p>0.05). The amounts of peroxide and thiobarbituric acid in experimental groups were lower than control. The amount of TVB-N increased in experimental groups compared to control. The total viable count and psychrophilic count of bacteria in the control group were higher than the experimental groups (p<0.05). The lowest counts of bacteria belonged to T6 (p<0.05). This study showed that the increased levels of Celmanax prebiotic in trout diet could increase shelf-life of fillet in the refrigerator.