The utilization of full fat soya and soybean meal proteins by rainbow trout (Oncorhynchus mykiss walbaum, 1792)

The Utilization of Full Fat Soya and Soybean Meal Proteins by Rainbow Trout (Oncorhynchus mykiss Walbaum, 1792)In this study, the effects different levels of full-fat soya and soybean meal on added to the ration of rainbow trout instead of fish meal on digestibility of nutrients and energy, growth (weight gain, specific growth rate, condition factor), feed utilization (feed conservation ratio, protein efficiency ratio), chemical quality of fish meat (crude protein, amino acid, crude fat, fatty acid, ash, nitrogen-free extract and moisture) and energy levels were investigated.Fort this purpose, control ration was prepared. As it contained 49.52% crude protein and 4287 kcal/kg total energy. 15% and 30% of fish meal in control diet were replaced with soybean meal to produce experimental diet 1 and 2. Similarly, 15% and 30% of fish meal in control diet were replaced with full fat soya to produce experimental diet 3 and 4. Crude protein and total energy levels of control and experimental diets were equaled.At the beginning of experiment, initial weight of rainbow trout was 49.98±0.32 g and total length of fish was 16.28±0.06 cm. 450 rainbow trout were used fort the study. Feeding rate was calculated as the feeding coefficient and percentage of their live weight. Feeding was applied three times in a day during five months.There was a significant difference in apparent digestibility coefficients of nutrients (crude protein, crude fat, ash, fiber, nitrogen-free extract, amino acids) and energy between the fish fed with control diet and experimental diets (p<0.05). In addition, live weight, total length, live weight gain, relative growth rate, specific growth rate, feed conversion ratio, protein efficiency ratio, protein productive index, carcass and fillet yields, proximate composition and total energy in fish meat of the experimental groups, the amino acids in fish meat valine, leucine, phenylalanine, lysine, histidine, serine, proline, aspartic acid, hidroxil proline, glutamine acid, were significantly different between the fish fed with control diet and the fish fed with experimental diets (p<0.05). Although there was not a significant difference (p>0.05) in ?n-3 fatty acids of fish meat between the fish fed with control diet and the fish fed with experimental diets, the lowest ?n-3 value was obtained from the fish fed with experimental diet 4. On the other hand, the highest ?n-6 fatty acid content was obtained from the fish fed with experimental diet 4. This was followed by experimental diet 3, 2, 1 and control diet respectively.In the present study, it was seen that the best result for a live weight and total length was obtained from the fish fed with control diet. This was followed by experimental diet 1, 3, 2 and 4 (p<0.05). In addition, it was observed that the lowest cost to produce 1 kg fish can be provided from experimental diet 1. This was followed by control diet, experimental diets 3, 2 and 4 respectively.Under the light of this study, it was concluded that soybean meal instead of fish meal can be used up to 40% in rainbow trout growth rations.Key words: Rainbow Trout, Oncorhynchus mykiss, Plant Protein, Full Fat Soya, Soybean Meal Amino acid, Fatty Acids, Growth Performance, Digestibilit