A nutrition trial with meagre, Argyrosomus regius was assessed to determine the effect of dietary replacement of fish oil (FO) by soybean oil (SO) on the growth, feed utilization, body composition, fatty acid composition and basic haematological parameters. Six isonitrogenous (47% crude protein) and isoenergetic (gross energy 22 kJ/g) experimental diets were formulated by replacing 0 (FO), 20 (S20), 40 (S40), 60 (S60), 80 (S80) and 100 (S100) % of the FO with SO. Fish were fed three times daily to near satiation for 14 weeks. The specific growth rate (SGR) of fish fed S100 diet was significantly lower than the other treatments, except SO80 diet. The fish fed SO100 diet displayed significantly higher feed conversion ratio than that of other diets (P < 0.05). It was observed that fish fed the SO100 and SO80 diets displayed haemoglobin (HGB) levels significantly lower (P < 0.05) than fish fed the SO20 diet. Packed cell volume (PCV) of fish fed SO20 diet was significantly higher compared to SO100. The white blood cell (WBC) and red blood cell (RBC) remained unaffected by dietary treatment. The docosahexaenoic acid (22:6n-3, DHA) and eicosapentaenoic acid (20:5n-3, EPA) levels of meagre were significantly reduced by the substituting of dietary SO by FO at the end of the feeding period. The level of linoleic acid (18:2n-6, LA) and linolenic acid (18:3n-3, LNA) significantly raised in fish fed with SO diets (P < 0.05). The results of this study showed that SO could be replaced FO up to 80% in meagre diet without negative effect on growth performance and basic haematological parameters. Furthermore, the maximum level of FO replacement with SO determined by second order polynomial regression analysis, was 30.1% on the basis of maximum SGR.

This study was conducted to test the replacement of fishmeal (FM) with a combination of corn gluten meal (CGM)-soybean meal (SBM) (at a ratio of 58 : 42, respectively) fortified with lysine, taurine and monocalcium phosphate (MCP) in turbot (Scophthalmus maximus) diets. FM as the main protein source in the control diet (FM100) was replaced in 15% decrements while increasing the combination of replacement material: 85% FM (FM85), 70% FM (FM70), 55% FM (FM55) and 40% FM (FM40). The diets were fed to triplicate groups (n = 25 per group) for 9 weeks (water temperature, dissolved oxygen, pH and salinity of 18.59 AE 0.06°C, 7.32 AE 0.02 mg L À1 , 7.73 AE 0.01 and 8.46 AE 0.04 g L À1 , respectively). Initial weight of fish was 286.1 AE 0.1 g. At the end of the experiment, growth, feed and nutrient utilization performance of fish fed FM85 and FM70 were similar to FM100, but a further increase in plant protein led to a significant reduction of these parameters. Whole body, fillet, viscera and liver nutrient compositions were not affected significantly; however, whole body lipid levels were significantly lower in fish on FM55 and FM40 than those on FM100. The fish in-fish out ratio in the diets decreased from 2.12 in FM100 to 1.00 in FM40. The results suggest that the FM level could be reduced by 30% with a combined use of CGM-SBM supplemented with lysine, taurine and MCP.

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This study was conducted to evaluate nutritional values of selected commercial fish meals (FM) with two experiments in diets of turbot. In experiment I, five diets based on two Peruvian anchovy meals (one is a flame-dried FM: Peru-1 and the other steam-dried FM: Peru-2), a Danish FM (Danish LT), a domestic anchovy LT meal (Domestic LT) and an Alaskan white FM (WFM) as major protein source were formulated to contain 56% protein.The diets were fed to fish with an initial average weight of 119.4 AE 0.1 g for 9 weeks. Growth rate, feed utilization, whole body and visceral compositions, nitrogen, lipid and energy balances did not significantly change in Experiment 1 among the treatments. In Experiment 2, four diets based on three FMs (Domestic LT, Danish LT and Peru-1) and their mixture (Mix FM) were formulated to contain 50% protein and fed to triplicated groups of fish with an average initial weight of 51.4 AE 0.1 g for 6 weeks. Once again, there were no significant differences in growth rate and feed consumption among the treatments. However, fish on Mix FM diet had significantly better FCR and PER than the others. The results of two experiment indicated that Danish LT and Domestic LT were better in terms of phosphorus (P) retention and losses than two Peruvian FMs and WFM, suggesting that although different sources of FMs were comparable in terms of growth and feed utilization, they could lead to substantial differences in environmental impacts.

This study was conducted to determine the effects of the use of farmed salmon oil (FSO) as a substitute for anchovy oil (AO) on growth and nutrient utilization performance, and proximate and fatty acid compositions of turbot, Psetta maxima. Two fish oil sources, AO and FSO, were incorporated into the diet at a level of 6.77% and fed to turbot with an initial average weight of 266.25 ± 0.53 g in brackish water for 9 wks. Each diet was tested in four replicates and fed to apparent satiation twice a day. At the end of the experiment, data of growth and nutrient utilization performances (feed conversion ratio, nitrogen, lipid and energy intakes, gains, and retentions), and organo‐somatic indices were similar between the dietary oil sources. Likewise, there were no significant differences in final whole body proximate compositions between two treatments. However, AO and FSO diets significantly affected whole body fatty acids and fatty acids classes. Briefly, FSO fish was characterized with higher n‐6 poly unsaturated fatty acids (PUFA) mainly 18:2n‐6 whereas AO fish with higher n‐3 PUFA and highly unsaturated fatty acids mainly 22:6n‐3. The whole body fatty acid profile reflected that of the diets. It is concluded that incorporation of FSO instead of AO in turbot diets supports similar growth and nutrient utilization performances but change whole body fatty acid profile.

This experiment aimed to determine the effects of feeding frequencies on growth, feed intake and feed conversion efficiency in turbot, (Scophthalmus maximus Linnaeus, 1758). Six treatments consisted of feeding twice a day for 6 and 7 days a week (6:1 (2) and 7:0 (2) respectively), feeding twice a day and then one or two days starvation (1:1 (2) and 1:2 (2) respectively), two days feeding and one day starvation (2:1 (2) ) and feeding once a day for six days a week (6:1 (1) ). Initial average weight of fish was 110.3±0.5 g. They were fed until apparent satiation in each meal regardless of the treatments for 6 weeks. Each treatment was tried in triplicate tanks. At the end of the experiment, fish particularly those on 7:0 (2) and 6:1 (2) performed significantly better than those on 1:2 (2) (p<0.05) in terms of daily growth coefficient. The differences in growth rate actually were a reflection, at large extend, of amount of food consumed. Briefly fish fed more frequently consumed more feed and individuals on 7:0 (2) , 6:1 (2) and 2:1 (2) had significantly higher feed intake than those on 1:2 (2) . On the other hand, feed intake per feeding day or per meal were inversely related with feeding days (n= 18, r 2 =0.89) and number of meals (n=18, r 2 =0.87). Feed conversion efficiency was not affected by the treatments. A quadratic broken line model estimated minimum number of daily meal for maximum growth as 1.756, equal to twice a day feeding for 6 days a week.

This study was carried out to determine the effects of replacement of wheat flour with wheat middling (WM) and supplemental phosphorus at a level of 1% on growth and nutrient utilization, whole body, fillet, viscera and liver proximate compositions in turbot, (Scophthalmus maximus Linnaeus, 1758). The control diet was based on a mixture of three fish meals and whole wheat flour. Fish with an average initial weight of 266.67±0.72 g were fed experimental diets for 9 weeks. Each treatment was tried in four replicates. At the end of the experiment, there were no significant effects of the treatment on growth rate, nutrient utilization parameters such as feed intake, feed conversion ratio, protein efficiency rate, nitrogen, lipid and energy gains and retentions, hepato-somatic index, viscero-somatic index, condition factor, whole body (except dry matter which was significantly lower in P added diet than the control) and organ nutrient compositions (P>0.05). The findings suggest that WM can totally replace wheat flour and there is a tendency of a positive contribution of dietary P supplementation on the response variables.

This study was conducted to identify optimum exchange ratio of canola meal in fish feeds instead of fishmeal, using %45 protein and %18 fat commercial control feeds and %10, %15, %20, %25 and %30 canola meal (KA) based feeds for sea breams with a starting weight of 49,86±0,009 gr by analyzing growth performance, food conversion ratio and digestibility. After 98 days of experiment, specific growth rate and relative weight gain although was statistically significantly different during 14-28 days (p<0,05), it was insignificant at the end of the trial. Food conversion ratio (FCR) was lowest for KA30 (4,54±0,1), and highest for KA10 (5,31±0,2) group, protein efficiency was highest in KA30 and lowest in KA10 group, productive protein value was highest in KA30 with 0,318±0,02 (p<0,05). Digestibility performance for crude protein and dry matter was the highest in the control group and lowest for KA10 group and for fats lowest was KA10 where highest was (p<0,05) KA30 with similar results compared to KA0 and KA15.