Effects of dietary soybean meal (HP310) source on growth performance and blood parameters of rainbow trout (Oncorhynchus mykiss)

The aim of present study was to evaluate the effect of replacing fish meal with modified soybean powder (HP310) on growth performance and immunity of rainbow trout (Oncorhynchus mykiss). So Fishmeal was replaced with HP310 at levels of 0، 25، 50، 75 and 100% in five experimental diets. A diet with 100% fishmeal (0% HP310) was used as control. Diets were fed to four replicate groups of 15 fish with an initial weight of 1. 17±0. 03 g for a period of 60 days. The results showed that diets with 25 and 50% of HP310 increased Feed Intake and thus increased Weight Gain، Specific Growth Rate and reduced Food Conversion Ratio (p<0. 05). But fish growth parameters decreased when 75 and 100% of substitution were used (p<0. 05). Furthermore، the results of blood parameters analysis، indicated that the amounts of Hemoglobin، Hematocrit and Red Blood Cells decreased by increasing the level of HP310 in experimental diets. But the difference between the control and the other treatments were not significant up to 75 percent replacement levels of diet. And only 10% HP310 treated showed a significant decrease compared to the control (P<0. 05). Study of white blood cells showed a significant increase with increasing levels of fish meal replacement diets compared to the control (P<0. 05). The present results indicated that soybean meal (HP310) can be replaced up to 50% of fish meal in rainbow trout’s diet without negative effects on growth performance and blood parameters.