This study aimed to assess the effect of date palm (Phoenix dactylifera) seed (DPS) extract at 0.5%, 1%, 2% and 4% as a dietary supplement over 60 days, on the growth and immune-physiology of common carp (Cyprinus carpio) fingerlings. The weight gain in fish fed with 0.5% DPS was significantly greater than other treatments and fish fed a control diet with no DPS (p < 0.05). With increasing DPS dosage above 0.5%, weight gain and growth rate gradually declined. Feed conversion ratio in fish fed 0.5% DPS was lower than other treatments, but not significantly so, except for the highest DPS concentration (4%). With respect to immunophysiological variables, fish treated with 0.5% DPS leucocyte, neutrophil, lymphocyte and monocyte counts that were generally equivalent to fish on a control diet, but significantly lower than fish treated with greater concentrations of DPS (p < 0.05). Chemilumincene response and lysozyme activity, as well as levels of total protein and albumin, were higher in all treated groups than the control. The highest levels of iron and high density lipoprotein (HDL) were observed in fish fed with 0.5% DPS, while the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), glucose, cholesterol, triglyceride, low density lipoprotein (LDH), thyrotropin, thyroxine and triiodothyronine were lower level in fish fed with 0.5% DPS than in all other treatments. In aquaculture practice, use of 0.5% DPS in commercial carp feed can improve the growth rate and condition of fish. K E Y W O R D Scommon carp, date seed extract, growth performance, immunophysiology

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Abstract:The potential of enzyme-treated soybean meal powder (HP310) as fish meal alternative in diets for rainbow trout weighing 1.17˘0.3 g was evaluated for 60 days. Fish meal was replaced with HP310 at 25%, 50%, 75% and 100% of experimental diets. A control group was also considered. The results showed that diets containing 75% and 100% HP310 had significantly higher feed conversion ratio and lower feed intake, weight gain and specific growth rate compared to fish feed diets containing higher levels of fish protein ingredients (p < 0.05). Results suggested use of 50% HP310 in trout diet had a positive effect on growth performance (p < 0.05). All fish feed diets with HP310 had lower hematocrit, hemoglobin and red blood cells compared to the control group, but the differences between the control and the other treatments up to 75% HP310 replacement levels of diet (p > 0.05). However increasing in level of HP310 in the diet caused a significant increase of the white blood cells (p < 0.05). The fish fed with a diet totally replaced by HP310 showed the highest values of ash and moisture content among the diets and showed significantly different levels when compared with the control and other feeding treatments (p < 0.05).

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