| Chinese mitten crab (Eriocheir sinensis) as the research object in this experiment is the aquaculture species unique to China. The purpose of this paper is to analyze n-3highly unsaturated fatty acids, Linolenic acid and choline requirement of juvenile Chinese mitten crab by animal nutrition and biochemical techniques. The results are briefly summarized as follows:1. Dietary n-3HUFA requirement of juvenile Chinese mitten crab(Eriocheir sinensis)A70-day feeding trial was conducted to investigate the effects of n-3HUFA requirement of juvenile Chinese mitten crab, Eriocheir sinensis. Semi-purified diets containing seven n-3HUFA levels (0,0.18,0.49,0.70,0.90,1.39and1.56%) were fed to Eriocheir. sinensis juveniles (2.26±0.06g) with four replicates each treatment. The results showed that dietary n-3HUFA had no significant effects on survival (P>0.05). Crab weight gain and specific growth rate significantly increased with dietary n-3HUFA level from0up to1.56%(P<0.05). Feed conversion ratio decreased significantly with dietary n-3HUFA increasing (P<0.05). The diets had no significant effect on body composition (P>0.05). The fatty acid composition of the hepatopancreas is basically the same to the fatty acid composition of the diet. The activity of lysozyme, phenol oxidase and superoxide dismutase increased with dietary n-3HUFA level from0up to1.56%(P<0.05). The activity of alkaline phosphatase and acid phosphatase increased as dietary n-3HUFA increased at first, and then decreased as n-3HUFA increased further. Broken-line regression analysis based on weight gain against dietary n-3HUFA levels indicated that the optimal dietary n-3HUFA requirements of juvenile E. sinensis were1.00%diet. 2. Dietary Linolenic acid requirement of juvenile Chinese mitten crab (Eriocheir sinensis), and the effect of dietary Linolenic acid and Linoleic acid on growth and non-specific immunityA42-day feeding trial was conducted to determine the dietary Linolenic acid (LNA)requirement of juvenile Chinese mitten crab, Eriocheir sinensis, and the effect of dietary LNA and Linoleic acid(LA) on growth and non-specific immunity.Casein and Gelatin were used as protein source, dextrin as sugar source. Semi-purified diets containing seven group with different LA-LNA levels (3-0,3-1,3-2,3-3,4-2,2-4and0-3) were fed to juveniles (0.29±0.02g) with four replicates each treatment. The results showed that crab weight gain and specific growth rate significantly increased with dietary LNA level (P<0.05). The appropriate amount of dietary LNA has a significant role in promoting the growth of the Chinese mitten crab, while the effect of LA is not obvious, LA acid can affect the survival rate of crab. Dietary LNA and LA had no significant effect on the body composition of Chinese mitten crab. The contents of hepatopancreas LA were at the same level though the dietary LA contents were different. The activity of phenol oxidase, superoxide dismutase and nitro blue tetrazolium show that LNA was greater than LA on the effect of immune function. Broken-line regression analysis based on weight gain against dietary Linolenic acid levels indicated that the optimal dietary Linolenic acid requirements of juvenile E. sinensis were1.24%diet. When dietary Linolenic acid and Linolenic acid ratio was0.56-0.74, juvenile Chinese mitten crab shown the best growth performance.3. Dietary choline requirement of juvenile Chinese mitten crab, Eriocheir sinensis, at two dietary phospholipids levelsA42-day feeding trial was conducted to investigate the effects of dietary phospholipids on the choline requirement of juvenile Chinese mitten crab, Eriocheir sinensis. Twelve purified diets were formulated containing two phospholipids levels (1and2%) and six choline chloride levels (0,250,500,1000,2000and4000mg/kg diet), and were fed to E. sinensis juveniles (0.22±0.01g) with four replicates each treatment. The results showed that dietary choline and phospholipids had significant interaction on survival, weight gain, specific growth rate and feed conversion ratio (P<0.05). Crabs fed diet with dietary1000mg/kg choline chloride (1%phospholipids) and500mg/kg choline chloride (2%phospholipids) obtained the highest survival rate, and significantly differed from that of other treatments with low choline chloride (P<0.05). Crab weight gain and specific growth rate significantly increased with dietary choline level from500up to4000mg/kg (P<0.05). Feed conversion ratio decreased significantly with dietary choline chloride increasing from1000to4000mg/kg (P<0.05) at1%phospholipids level At2%phospholipids level, feed conversion ratios of crab fed diet with500and1000mg/kg choline chloride were significantly lower than that of0mg/kg group (P<0.05), but no significant differences were detected among250,2000and4000mg/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 phospholipids level (P<0.05). Broken-line regression analysis based on weight gain against dietary choline levels indicated that the optimal dietary choline requirements of juvenile E. sinensis were1429.65mg/kg and529.65mg/kg at1%and2%phospholipids levels, respectively. |
PDF Full Text Request