【作者】 唐宏刚；

【导师】 吴天星；

【作者基本信息】 浙江大学 ， 化学， 2008， 博士

【摘要】 大黄鱼属于肉食性鱼类,是我国重要的海水经济鱼类品种之一。由于营养价值高、味道鲜美,深受消费者欢迎。由于过度捕捞,野生大黄鱼资源已基本枯竭。自上世纪80年代人工育苗的成功,大黄鱼养殖业得到了迅速发展。本研究对传统网箱养殖大黄鱼的肌肉生化组分进行分析,比较饲喂冰鲜鱼和配合饲料的大黄鱼肌肉氨基酸、脂肪酸含量差异;并在日粮中添加不同水平鱼蛋白水解物(FPH),探讨其对大黄鱼生长、血液生化指标、肌肉品质和免疫性能的影响。试验共分5个部分进行。1传统网箱养殖大黄鱼肌肉成分分析本研究测定了传统网箱养殖条件下饲喂冰鲜鱼和配合饲料的大黄鱼肌肉组成成分,研究两种日粮对肌肉氨基酸、脂肪酸组成的影响。研究发现,两组鱼肌肉蛋白质、粗灰分含量没有显著性差异;饲喂配合饲料的大黄鱼脂肪含量显著低于冰鲜鱼组(P＜0.05)。饲喂配合饲料的大黄鱼肌肉苏氨酸、谷氨酸和丙氨酸含量显著高于冰鲜鱼组(P＜0.05),而甘氨酸、蛋氨酸、亮氨酸、苯丙氨酸、赖氨酸、精氨酸和脯氨酸含量则显著低于冰鲜鱼组(P＜0.05)。与冰鲜鱼组相比,饲喂配合饲料大黄鱼肌肉饱和脂肪酸及单不饱和脂肪酸含量升高,而多不饱和脂肪酸含量降低,两组之间的差异显著(P＜0.05)。在多不饱和脂肪酸中,冰鲜鱼组n-3 PUFA和n-6 PUFA含量显著高于配合饲料组(P＜0.05);但n-3/n-6比值则显著低于配合饲料组(P＜0.05)。2日粮FPH水平对大黄鱼生长性能、消化酶活性的影响以基础日粮为对照,FPH添加水平分别为5%,10%,15%(试验1-3组)。经过10周的饲喂,结果显示如下:试验2组、3组大黄鱼的TWG、RWG和SGR显著高于对照组(P＜O.05),在所有试验组中,以试验2组的添加水平为最佳,TWG、RWG和SGR达到最高,分别为:101.9±11.89g、62.41±7.62%、0.86±0.08%。三种添加水平FPH对大黄鱼的肥满度和脏体指数没有显著影响,与对照组比较,试验2组、3组的大黄鱼肝体指数显著性降低(P＜0.05)。与对照组相比,试验各组鱼胃、幽门盲囊、前肠和后肠蛋白酶活性显著提高(P＜0.05)。其中试验2组和3组胃、后肠蛋白酶活性达到最高,两组之间差异不显著(P＞0.05)。各组大黄鱼肝胰脏蛋白酶活性没有随着FPH的添加而发生显著变化(P＞0.05)。研究表明,FPH对大黄鱼各消化器官的淀粉酶、脂肪酶活性没有显著影响。3日粮FPH水平对大黄鱼血清生化指标的影响日粮FPH对大黄鱼血清生化指标影响的研究结果表明,与对照组相比,试验各组大黄鱼血清总蛋白含量显著增加(P＜0.05),尿素氮、总胆固醇水平显著下降(P＜0.05),谷丙转氨酶、高密度脂蛋白胆固醇和镁的水平没有显著变化。试验2组、3组血清钙含量显著提高(P＜0.05),而甘油三酯含量显著降低(P＜0.05),组间差异不显著。4日粮FPH水平对大黄鱼肌肉品质的影响试验各组大黄鱼肌肉的水分、粗蛋白含量高于对照组,而粗脂肪含量低于对照组,差异均显著(P＜0.05)。随着日粮FPH水平的增加,大黄鱼必需氨基酸和呈味氨基酸的总含量得到了显著性提高(P＜0.05),但试验各组之间没有显著差异。试验组大黄鱼肌肉饱和脂肪酸含量显著低于对照组(P＜0.05),而单不饱和脂肪酸和多不饱和脂肪酸含量显著高于对照组(P＜0.05)。在试验各组的多不饱和脂肪酸中,EPA和DHA含量均得到了显著性提高(P＜0.05)。与对照组相比,饲喂添加三种不同水平FPH日粮的大黄鱼肌肉SOD活性和MDA含量没有显著差异(P＞0.05);试验各组大黄鱼肌肉中肌苷酸的含量显著提高(P＜0.05),各组之间差异不显著(P＞0.05)。采用微波蒸馏-固相微萃取技术萃取大黄鱼肌肉中的挥发性成分,并通过气相色谱质谱联用法来分析、鉴定,共检出54种化合物,其中主要为挥发性醇类和羰基化合物。通过比较发现,日粮FPH水平对挥发性成分的百分含量没有影响。5日粮FPH水平对大黄鱼免疫及抗氧化性能的影响不同添加水平的FPH对大黄鱼肾体指数和脾体指数没有显著影响。FPH对血清溶菌酶、补体C3和C4、IgM含量的影响研究表明:试验2组和试验3组的效果最好,除血清补体C3外,各指标均显著高于对照组和试验1组(P＜0.05),且组间差异不显著;与对照组相比,试验1组大黄鱼血清溶菌酶、补体C4、IgM含量没有显著变化,补体C3水平显著提高(P＜0.05)。各组大黄鱼外周血液NBT阳性细胞数量没有显著变化(P＞0.05)。试验各组大黄鱼肝脏SOD活性显著高于对照组(P＜0.05),组间差异不显著;肝脏GPX和CAT活性没有显著变化(P＞0.05);试验各组的CAT/SOD比值均低于对照组。更多还原

【Abstract】 Large yellow croaker (Pseudosciaena crocea) belongs to predatory fish species, and is one kind of economically important marine fish species in China. With high nutritive value and better flavor, it is popularly consumed by people. Due to excessive harvest, wild large yellow croaker has nearly been depleted. Since the success of artificial hatchery in the 1980s, its culturing has been developed rapidly. The purpose of the present study was to determine biochemical composition of large yellow croaker cultured in traditional sea-cages. Comparison of amino acid, fatty acid composition in muscle was conducted between this species fed different diets (raw fish and commercial feed). The effects of dietary fish protein hydrolysate on growth performance, metabolism, flesh quality, immunity performance were also evaluated. This dissertation was described in the following five sections.1 The analysis of biochemical composition in muscle from large yellow croaker cultured in traditional sea-cagesThe biochemical composition of fillets in large yellow croaker cultured in traditional sea-cages was determined. The comparison of amino acid and fatty acid composition was made between the fish fed with raw fish (RF) and commercial feed (CF). The analysis results showed that there were no significant differences in crude protein and ash content between two groups. Fish in CF group had lower level of crude fat content (P<0.05). Threonine, glutamic acid and alanine levels were significant higher, while glycine, methionine, leucine, phenylalanine, lysine, arginine and praline levels were significant lower in CF group (P<0.05). The percentages of total saturated fatty acids and monounsaturated fatty acids were significantly higher, while the corresponding total polyunsaturated fatty acids content was significantly lower in CF group (P<0.05). Among polyunsaturated fatty acids, n-3 PUFA and n-6 PUFA contents in RF group were higher. And large yellow croaker fed raw fish had the lower value of n-3/ n-6 ratio (P<0.05). 2 Effects of dietary FPH on growth performance and digestive enzyme activity in large yellow croakerThe study was conducted to investigate the effects of dietary supplementation with fish protein hydrolysate (FPH) on growth performance and digestive enzyme activity of large yellow croaker (Pseudosciaena crocea). Fish were fed 4 diets: basal diet only (control group, CG) or diets supplemented with FPH at doses of 5%, 10%, and 15% (treatment group, TG 1-3). The trial lasted for 10 weeks.Compared with the control group, total weight gain (TWG), relative weight gain (RWG) and specific growth rate (SCR) in TG2 and TG3 were significantly increased (P<0.05). Among all treatment groups, the results in TG2 were best: 101.9±11.89g, 62.41±7.62% and 0.86±0.08%, respectively. No significant differences were observed in the condition factor and visceral index of fish in four groups. Hepatosomatic indices of fish in TG2 and TG3 were significantly lower than CG (P<0.05).The protease activity of stomach, pylorus cecum, foregut and hindgut in all treatment groups were significantly higher than CG (P<0.05). Protease activity of stomach in TG2 and TG3 peaked, no significant difference was observed between two groups (P<0.05).There were no significant differences in protease activity of hepatopancreas among all groups (P<0.05). FPH had no significant effects on lipase and amylase activity of large yellow croaker.3 Effects of dietary FPH on serum biochemical indices in large yellow croakerThe results showed that serum total protein level in treatment groups were significantly higher (P<0.05), while urea nitrogen and total cholesterol levels were significantly lower than control group (P<0.05). No significant differences were found in glutamate-pyruvate transaminase, high density lipoprotein- cholesterol and magnesium levels among all groups. Serum calcium levels in TG2 and TG3 were significantly increased (P<0.05), triacylglycerol levels were significantly decreased (P<0.05). The differences between TG2 and TG3 were not significant.4 Effects of dietary FPH on flesh quality in large yellow croakerThe effects of dietary supplementation with FPH on body composition, IMP and volatile flavor components of large yellow croaker (Pseudosciaena crocea) were investigated. Moisture and crude protein content in treatment groups were significantly higher, while crude lipid content were significantly lower than control group. With the increasing levels of dietary FPH, essential amino acids and flavour amino acids contents in fillets of large yellow croaker increased significantly (P<0.05). The differences among treatment groups were not significant. Fish in all treatment groups contained lower SFA contents and higher MUFA, PUFA contents. Among PUFAs in treatment groups, EPA and DHA levels were significantly increased (P<0.05). The differences of SOD activity and MDA content among all groups were not significant. IMP content in fillets of large yellow croaker was significantly increased by supplementing FPH into basal diets (P<0.05).Volatile flavour compounds from muscle of large yellow croaker were extracted by microwave distillation and solid phase microextraction. The technique of gas chromatography-mass spectrometry was employed to analyze the components, and 54 compounds (alcohols, aldehydes, and ketones mostly) were identified. By comparing the results of all groups, the percentage profiles of components were not affected by dietary FPH levels.5 Effects of dietary FPH on immunity and antioxidation in large yellow croakerThe results showed that dietary FPH levels had no significant influence on KBI and SBI in large yellow croaker. Positive results were observed in immune parameters (lysozyme activity, serum complement, IgM). Lysozyme activity, complement C4 and IgM levels were significantly increased (P<0.05) in TG2 and TG3. Compared with CG, complement C3 level in TG1 were significantly increased (P<0.05), while no significant difference was shown in levels of lysozyme activity, complement C4 and IgM between two groups. The number of NBT-positive cells in peripheral blood among all groups were not significantly different (P>0.05).Hepatic SOD activities in treatment groups were all significantly higher than control group (P<0.05). The differences among three treatment groups were not significant. No significant differences were found in hepatic GPX and CAT activities among all groups. And the ratios of CAT/SOD in treatment groups were lower than control group.更多还原