Authors : Ahmet Adem Tekinay , Emrah Deveciler and Derya Guroy
Abstract: A 12 week experiment was conducted to investigate the effect of feeding rainbow trout Oncorhynchus mykiss with diets containing different levels of tuna by-products (tuna fish meal and tuna fish oil) on feed intake, growth performance, nutrient utilization and body composition in seawater condition. Fish were fed 5 experimental diets (42% crude protein and 12% crude fat), commercial diet (Com) with 42% protein and 16% crude fat, anchovy meal diet (Anc) and the diets contained different levels of tuna by-products (54.6, 45.5 and 36.4%) to replace 75, 60 and 50% of dietary protein, respectively. Specific Growth Rate (SGR) and Feed Conversion Ratio (FCR) were significantly influenced by replacement of fish meal by tuna by-products (p<0.05). The poorest performance in terms of SGR and FCR were recorded in Tuna groups irrespective of dietary inclusion. The hepatosomatic index, crude protein content and crude ash in whole body were not influenced (p>0.05); however the condition factor, moisture and lipid in whole body were significantly affected by dietary treatment (p<0.05). Within the conditions of this experiment, the results showed that tuna by-products with the present quality are not qualified protein or energy source for rainbow trout at high inclusion levels. However, further studies are required to investigate the processing techniques and storage conditions of these products to resolve the palatability problem.
Ahmet Adem Tekinay , Emrah Deveciler and Derya Guroy , 2009. Effects of Dietary Tuna By-Products on Feed Intake and Utilization of Rainbow Trout Oncorhychus mykiss. Journal of Fisheries International, 4: 8-12.