水体盐度与饲料脂肪含量对尼罗罗非鱼生长、营养组成和肉质的影响

为研究水体盐度和饲料脂肪含量对尼罗罗非鱼生长、营养组成和肉质的影响,本实验设置0、8和16共3个盐度梯度,每个梯度分别投喂中脂(6%)和高脂(12%)饲料,投喂初始体质量为(5.0±0.2) g的尼罗罗非鱼8周,并测定生长性能、血清生化指标、肌肉营养成分和肉质相关指标。结果显示,在中脂饲料投喂下,与对照组(盐度为0)和高盐组(盐度为16)相比,中盐组(盐度为8)的尼罗罗非鱼具有最大终末体质量、躯壳比、脂体比、肌肉蛋白质含量、肌肉氨基酸和乳酸含量和总产肉率,但其饲料系数、脏体比、肝体比和肌肉p H值显著降低;而中脂高盐组的尼罗罗非鱼其饲料系数、肥满度、脏体比、肝体比、全鱼总脂、肝脏甘油三酯、血糖、血清乳酸和血清甘油三酯含量、血清谷草转氨酶活性较高,但全鱼和肌肉水分、全鱼灰分、产肉率和肌肉离心失水率降低。在高脂饲料投喂下,随着盐度的上升,其终末体质量、成活率和脂体比降低,但饲料系数、脏体比、肝体比和肥满度增大。其中,高脂中盐组尼罗罗非鱼的肌肉蛋白以及氨基酸含量显著降低,而高脂高盐组的全鱼灰分、肝脏甘油三酯、血糖、谷草转氨酶活性、肌肉总脂、肌肉甘油三酯和磷脂含量显著提高,但全鱼总脂、肝糖原、...

Influences of water salinity and dietary fat content on growth, nutrient composition and fillet quality of Nile tilapia (Oreochromis niloticus)

In order to study the combined effects of water salinity and dietary fat content on the growth, fillet nutrient composition and quality of Nile tilapia (Oreochromis niloticus), we designed the following experiment. Three different salinities (0, 8, 16) were set to raise O. niloticus [initial weight (5.0±0.2) g]. And in each salinity-group, O. niloticus was fed with two lipid-content diets, medium and high lipid diet respectively (MFD, 6% and HFD, 12%). After 8 weeks of breeding, the fish were sampled, and the growth, serum biochemical parameters, muscle nutritional composition and fillet quality related parameters were assayed. The results showed that, among MFD groups, the fish in medium salinity group (salinity 8) showed the highest final weight (FW), carcass ratio (CR), mesenteric fat index (MFI) and contents of total protein, amino acids and lactate in the muscle, but decreased feed conversation ratio (FCR), viscerosomatic index (VSI), hepatosomatic index (HSI) and pH of muscle, compared with the control group (salinity 0) and high salinity group (salinity 16). And compared with the control group and middle salinity group, the fish in MFD-high salinity group showed increased FCR, condition factor (CF), VSI, HSI, whole fish lipid, hepatic triglyceride (TG) and serum glucose, lactate, TG and glutamic oxaloacetic transaminase (GOT), but reduced whole fish moisture, muscle moisture, whole fish ash, meat yield (MY) and centrifugal water loss. In HFD group, with the increase of salinity, FW, survival rate and MFI were gradually decreased, and FCR, VSI, HIS and CF were increased. In HFD group, the fish in medium salinity group showed reduced muscle total protein and amino acid content. HFD-high salinity cultured fish showed increased whole fish ash, hepatic TG, serum glucose, GOT, muscle total protein, muscle TG and PL content, and decreased whole body lipid, hepatic glycogen, MY, centrifugal water loss, pH. However, either in freshwater or saltwater, the fish fed with HFD showed higher fat accumulation and muscle lactic acid content, but lower survival rate and MY, compared with MFD. Particularly in saltwater, the HFD fed fish showed significantly higher fat accumulation and muscle lactic acid content, but lower survival rate, FCR and MY. These results showed that suitable salinity (e.g. 8) of aquaculture water environment can improve the growth and flesh quality of O. niloticus, but the combination of HFD and high water salinity had negative effect on growth and flesh quality of O. niloticus.