饲料蛋白质脂肪比与不同生长阶段团头鲂全鱼蛋白质、脂肪含量及肌肉氨基酸、脂肪酸组成的关系

Relationship between Dietary Protein to Lipid Ratio on Protein and Lipid Contents in Whole-Body,and Amino Acid and Fatty Acid Compositions in Muscle of Blunt Snout Bream (Megalobrama amblycephala) in Different Growth Stages

本试验旨在研究饲料蛋白质脂肪比对不同生长阶段团头鲂全鱼蛋白质含量、肌肉氨基酸组成、全鱼脂肪含量、肌肉脂肪酸组成的影响。配制饲料蛋白质脂肪比分别为2．63（P26．93/L10．24；P为饲料蛋白质百分含量，L 为饲料脂肪百分含量）、3．20（P28．50/L8．91）、4．07（P30．09/L7．39）、5．33（P31．63/L5．93）、7．25（P33．78/L4．66）、10．64（P35．63/L3．35）的6种试验饲料。以初均重为（10．37±0．69）g/尾（小鱼种）、（35．07±0．45）g/尾（中鱼种）、（101．65±1．82）g/尾（育成鱼）3个生长阶段的团头鲂为试验鱼，在相同饲料配方模式下，分别在室内水族系统（小鱼种）和池塘网箱（中鱼种和育成鱼）养殖64、85、56 d。每个生长阶段的养殖试验均设置6个组，每组4个重复，每个重复20尾鱼。结果表明：随着饲料蛋白质脂肪比的增加，3个生长阶段团头鲂的特定生长率、蛋白质沉积率均呈先升后降的趋势，饲料系数则呈先降后升的趋势，均在5．33组达到极值。团头鲂全鱼蛋白质含量、肌肉氨基酸组成主要受生长阶段的影响，鱼体越小全鱼蛋白质含量越低，肌肉氨基酸含量越高；在饲料蛋白质脂肪比为4．07～5．33时可以获得较高的蛋白质和氨基酸沉积量。对于同一个生长阶段，全鱼蛋白质含量与饲料蛋白质脂肪比具有正相关关系。团头鲂全鱼脂肪含量受饲料脂肪含量、脂肪酸组成的影响较大，同时也受到养殖水温变化的影响，低水温下鱼体沉积的脂肪量较高。对于同一个生长阶段，全鱼脂肪含量与饲料蛋白质脂肪比呈幂函数关系。与饲料脂肪酸组成相比，团头鲂肌肉脂肪酸组成有一定程度的改变，表明鱼体具备一定的转化饲料脂肪酸的能力，随着团头鲂的生长，这种能力得到增强。

This experiment was conducted to study the effects of dietary protein to lipid ratio on whole-body protein content,muscle amino acid composition,whole-body lipid content and muscle fatty acid composition of blunt snout bream（ Megalobrama amblycephala）in different growth stages. Six experimental diets were for-mulated with different protein to lipid ratios,which were 2.63（ P26.93/L10.24;P was the percentage content of dietary protein,and L was the percentage content of dietary lipid）,3.20（ P28.50/L8.91）,4.07（ P30.09/L7.39）,5.33（P31.63/L5.93）,7.25（P33.78/L4.66）and 10.64（ P35.63/L3.35）,respectively. Blunt snout bream in 3 growth stages with the initial average weight of（10.37±0.69）g/fish（juvenile fingerlings）, （35.07±0.45）g/fish（medium fingerlings）and（101.65±1.82）g/fish（premature fish）were launched in circular aquarium system（ juvenile fingerlings）and conducted in pond cages（ medium fingerlings and prema-ture fish）for 64,85 and 56 days,respectively. Six groups were divided into each growth stage with 4 repli-cates,and each replicate had 20 fish. The results showed as follows：with the dietary protein to lipid ratio in-creasing,the special growth ratio,protein deposition rate and feed conversion rate of blunt snout bream in 3 growth stages all showed a trend of firstly rise and then decline,and the extreme values were all found in 5.33 group. Whole-body protein content and muscle amino acid composition of blunt snout bream were mainly influ-enced by the growth stage. The smaller fish had the lower whole-body protein content,while the amino acid content of muscle was higher. When dietary protein to lipid ratios were 4.07 to 5.33,the blunt snout bream gained the higher protein and amino acid deposition. There was a positive correlation between whole-body pro-tein content and dietary protein to lipid ratio for the same stage. Dietary lipid content and fatty acid composition had a great impact on the whole-body lipid content of blunt snout bream. Changes in water temperature also had some influences on the whole-body lipid content of blunt snout bream ,and the lower temperature was good for the body lipid deposition. There was a power function relationship between whole-body lipid content and dietary protein to lipid ratio for the same stage. Compared with dietary fatty acid composition,the muscle fatty acid composition of blunt snout bream had a certain degree of change,which illustrated that blunt snout bream had some ability to transform the dietary fatty acids,and this ability strengthened with the growth of blunt snout bream.