جستجوی مقالات مرتبط با کلیدواژه « تغذیه ماهی » در نشریات گروه « آب و خاک »

The present experiment evaluates the effects of some carbohydrate sources (corn, barley and millet) and the replacement of corn with different levels (0, 25, 50, 75, 100%) of barley and millet on the performance of common carp (Cyprinus carpio L.). In a completely randomized block design, 540 grower fish with an average body weight of 70 gr, were divided into 27 groups, 20 fish per group. Nine different diets were used and each diet was assigned to triplicate groups of fish for eight weeks. Analyses of data showed that the replacement of corn by barley and millet resulted in a higher weight gain. The highest and lowest weight gains were observed with diets having 50 percent barley and 100 percent millet substitutions, respectively, although the differences with the control diet were not significant. Diets with 50 and 100 percent barley for corn substitutions showed a greater specific growth rate (SGR). As for the food conversion ratio (FCR), all the diets having barley and millet, irrespective of substitution levels, showed a better FCR relative to the control diet. However, the diet with 100 percent barley substitution had the best FCR, but no significant differences were observed (P>0.05) with the control diet. In general, the performance of barley was better than that of corn and millet, and millet was relatively better than corn. However, these results indicate that barley and millet can be suitable replacements for imported corn in diets used for common carp.

A 46-day feeding trial was conducted with rainbow trout (Oncorhynchus mykiss</em>) to examine the effects of partial substitution of plant protein sources with fish meal in diets. Three different sources of plant protein including soybean, sunflower and cottonseed meals were substituted by fish meal at four levels of 10, 20, 30 and 40 percentages. Each diet was assigned to triplicate groups of fish in a completely randomized design as a 3×4 factorial arrangement, with a control diet. Seven hundred and eighty fish were used in this trial. Twenty fish were randomly assigned to each of 39 pens and were acclimated in these pens to the experimental conditions two weeks before treatments began. This substitution caused no significant differences in all the criteria measured with control diet. Fish fed diets of 30 and 40 percent soybean meal substitution showed greater weight gain and better growth performance, lower FCR and higher PER values in comparison with the fish receiving other diets, although the differences were not significant. Irrespective of substitution levels, comparison of fish fed by three different sources of plant protein in their diets showed that the fish fed diet containing sunflower meal had significantly (p<0.0l) lower final mean weight and growth performance, higher FCR and lower PER than the fish receiving soybean and cottonseed meal diets. Relative liver weight of fish receiving soybean meal diets was significantly (p<0.0l) higher than those fed with cottonseed meal diets, but the difference was not significant when compared with the fish fed with the sunflower meal diets. Partial replacement of cottonseed meal resulted in a higher energy availability to fish and also better performance of fish. However, diets containing soybean meal showed not much effects on performance of rainbow trout. These results indicate that cottonseed and soybean meals can be recommended as a suitable and fish meal-sparing ingredient in diets for rainbow trout.