Dietary choline requirements of juvenile Chinese mitten crab,Eriocheir sinensis at two dietary phospholipid levels

A 42-day feeding trial was conducted to investigate the effects of dietary phospholipids on the choline requirement of the juvenile Chinese mitten crab,Eriocheir sinensis.Twelve purified diets were formulated con-taining two phospholipid levels(1% and 2%) and six choline chloride levels(0,250,500,1 000,2 000 and 4 000 mg/kg diet),and were fed to E.sinensis juveniles(0.22g±0.01g) with four replicates in each treatment.The results showed that dietary choline and phospholipids had a significant interaction on survival,weight gain,specific growth rate and feed conversion ratio(P0.05).Crabs fed diets with 1000 mg/kg dietary choline chloride(1% phospholipids) and 500 mg/kg choline chloride(2% phospholipids) obtained the highest survival rate,and sig-nificantly differed from that of other treatments with low choline chloride(P0.05).Crab weight gain and specific growth rate significantly increased with dietary choline levels from 500 to 4000 mg/kg(P0.05).Feed conversion ratio decreased significantly with dietary choline chloride increasing from 1 000 to 4 000 mg/kg(P0.05) at the 1% phospholipid level.At the 2% phospholipid level,feed conversion ratios of crabs fed diets with 500 and 1000 mg/kg choline chloride were significantly lower than those of the 0 mg/kg group(P0.05),but no significant dif-ferences were detected among the 250,2 000 and 4 000 mg/kg groups.Whole body crude lipid hepatopancreas triglycerides,hepatopancreas total cholesterol,hepatopancreas glutamate pyruvate transaminase and glutamate aspartate transaminase activities significantly decreased with choline chloride increase,regardless of the phos-pholipid level(P0.05).Broken-line regression analysis based on weight gain against dietary choline levels indi-cated that the optimal dietary choline requirements of juvenile E.sinensis were 1 429.65 mg/kg and 529.65 mg/kg at the 1% and 2% phospholipid levels,respectively.