The Optimal Dietary Proportions of Spray-dried Blood Cells to Fish Meal for Juvenile Gibel Carp(Carassius auratus gibelio)

This experiment was conducted to study the effects of substituting fish meal with spray-dried blood cells on growth performance of juvenile gibel carp,and to discuss the feasibility of substituting of fish meal with spray-dried blood cells which is achieved by the optimal combination of feed ingredients.Six experimental diets were formulated isonitrogenously,isolipidicly and isophosphorously.The levels of total lipid and total phosphorus were balanced by soybean oil and Ca(H2PO4)2,respectively,and the level of total nitrogen was balanced by cross combination of spray-dried blood cells and fish meal.Two hundred and seventy juvenile gibel carp(Carassius auratus gibelio) with an initial average body weight of(18.40±1.07) g were randomly assigned to six groups with three replicates in each group and fifteen fish per replicate.The diets of six groups contained 0(control group),2.5%,5.0%,7.5%,10.0% and 11.5% spray-dried blood cells,respectively,and contained 13.8%,10.7%,7.8%,4.8%,1.8%,and 0 fish meal,correspondingly.The experimental period lasted for 83 days.The results showed that compared with the control group,when the diets contained 7.5%,10.0% and 11.5% spray-dried blood cells,the specific growth rate,protein and lipid deposition rate of fish were significantly increased(P0.05),and the feed conversion rate was significantly decreased(P0.05),while the body indices and body composition were not significantly different(P0.05).However,the survival rate of fish was decreased when the diet contained 11.5% spray-dried blood cells.In conclusion,comprehensively considering the dietary nutritional balance,the optimal proportions of spray-dried blood cells to fish meal in the diets for juvenile gibel carp are between(7.5%︰4.8%) to(10.0%︰1.8%).