卵形鲳鲹消化酶活性的研究ⅢpH对幼鱼和成鱼消化酶活性的影响

研究了pH对卵形鲳鲹幼鱼和成鱼3种主要消化酶(蛋白酶、淀粉酶和脂肪酶)活力的影响。实验用鱼暂养7 d后解剖取样,在设计的10个酶反应pH值(2.2,3.2,4.2,5.2,6.2,7.2,8.0,8.6,9.6,10.6)下测定消化酶活力。结果表明:卵形鲳鲹胃内pH为强酸性,幼鱼肠内为中性偏酸性,肝、幽门盲囊和成鱼肠内为中性偏弱碱性。胃蛋白酶的最适pH值幼鱼为2.2,成鱼为3.2;肝、幽门盲囊和肠的蛋白酶活性最适pH值幼鱼为7.2,成鱼为8.0。淀粉酶活性的最适pH值幼鱼为8.0,成鱼为8.6。脂肪酶活性的最适pH值均为弱酸性,幼鱼和成鱼均为6.2。卵形鲳鲹幼鱼和成鱼3种相同消化酶活性的变化趋势相似,并以胃蛋白酶、肠淀粉酶、肠脂肪酶的活力最高。     

Effects of different dietary lipid sources on growth performance,body composition and lipid metabolism‐related enzymes and genes of juvenile golden pompano,Trachinotus ovatus

Three groups of juvenile golden pompano, Trachinotus ovatus (54.75 ± 0.25 g), were each fed one of three diets containing different lipid sources: fish oil (FO), soybean oil (SO) and lard oil (LO). Fish were reared in sea cages for 8 weeks, and the fish fed the FO diet had significantly higher specific growth rate (SGR) but lower condition factor (CF) than the other treatments. The fatty acid (FA) composition of whole‐body lipids was closely correlated with those in the diets. Although no differences can be found in hepatic fatty acid synthase (fasn) activity, the carnitine palmitoyl transferase 1 (cpt1) activity in fish fed the FO diet was significantly higher compared with other treatments. In addition, the relative gene expression of lipid metabolism‐related enzymes, such as cpt1, fas, apolipoprotein B100 (apoB100), delta‐6 fatty acyl desaturase (fadsd6) and fatty acid‐binding protein 1 (fabp1), was also influenced by the different dietary lipid sources. Serum triglyceride (TG) and glucose content in fish fed the LO and FO diets were significantly higher than those in the SO group. Accordingly, it can be concluded that FO could not be completely replaced by SO or LO in golden pompano diets. The lipid sources of a diet could impose significant influence on body condition factor and hepatic lipid metabolism of golden pompano.     

丁香精油抑菌保鲜衬垫协同气调包装对金鲳鱼品质影响

为延长金鲳鱼货架期,以金鲳鱼为研究对象,采用不同方式[样品置于PP托盘PE包装-1 ℃贮藏为对照组、样品置于PP托盘气调包装(55%O₂₊₃₀%CO₂₊₁₅%N₂)-1 ℃贮藏为处理组A、样品置于PP托盘并复合保鲜抑菌衬垫处理PE包装-1 ℃贮藏为处理组B、复合抑菌保鲜衬垫协同气调包装(55%O₂₊₃₀%CO₂₊₁₅%N₂)-1 ℃贮藏为协同组]对金鲳鱼进行低温贮藏。结果表明,与对照组相比,处理组A、处理组B、协同组均可有效抑制金鲳鱼pH值、挥发性盐基氮、菌落总数、硫代巴比妥酸反应物值(thiobarbituric acid reactive substance,TBARS)及K值上升,同时,可显著延缓其盐溶性蛋白溶出比及总巯基含量下降(P＜0.05);贮藏中后期(6~8 d),协同组效果显著优于处理组A、处理组B(P＜0.05);贮藏末期(第8天),协同组挥发性盐基氮、菌落总数、K值分别为11.76 mg/100g、3.74 lg CFU/g、14.81%,就上述3个指标而言,协同组较对照组可延长金鲳鱼货架期约4 d;相关性分析可知,pH值、挥发性盐基氮、菌落总数、TBARS、K值呈高度正相关性,上述指标均与盐溶性蛋白溶出比及总巯基含量呈高度负相关,且有统计学意义(P＜0.01),为金鲳鱼低温储运提供数据支持。     

卵形鲳鲹生肌调节因子基因家族的鉴定及在胚胎中的表达

为研究卵形鲳鲹生肌调节因子(MRF)在胚胎发育中所发挥的重要作用,对卵形鲳鲹MRF基因家族进行了全基因组鉴定和生物信息学分析,并对其在13个胚胎发育阶段的基因表达进行了定量分析.结果表明:在卵形鲳鲹基因组中共鉴定出5个MRF基因家族成员:MyoD1、MyoD2、Myf5、Myf6和MyoG,分别编码297、263、24...     

卵形鲳鲹营养需求与饲料研究进展

卵形鲳鲹(Trachinotus ovatus)是我国近年来快速发展起来的重要海水养殖鱼类，其年产量高达12万t。目前，国内外有关该鱼的营养需求与饲料研究已有较多报道，但对有些营养素的研究还是空白。本文主要就其蛋白质、氨基酸、脂肪、脂肪酸、碳水化合物和微量营养素的需求，蛋白源和脂肪源替代鱼粉和鱼油，功能性饲料添加剂应用等方面的研究进展进行综述，以期为该鱼的精准营养研究及高效低成本环保配合饲料的研发提供参考资料，从而推动其养殖业的健康可持续发展。     

卵形鲳鲹幼鱼的饥饿和补偿生长研究

研究了卵形鲳鲹(Trachinotus ovatus)幼鱼在不同饥饿时间(1、2、5、7 d)处理后再恢复投喂的补偿生长。室外水泥池和近海网箱两次实验结果均显示,在前15 d、30 d内,饥饿1 d、2 d组卵形鲳鲹生长略快于对照组,出现完全补偿生长现象。第一次实验饥饿5 d、7 d组的鱼在相同的时间内,体重的增加量未能赶上对照组,为部分补偿生长。饥饿组饲料转化效率高于对照组,且随饥饿时间的延长呈增大趋势;摄食率也随饥饿时间的延长而增大,但饥饿1 d、2 d组摄食率低于对照组,各饥饿组总摄食量均低于对照组,表明卵形鲳鲹幼鱼的补偿生长主要是通过提高饲料转化效率来实现的。对鱼体进行生化组成的结果分析发现:饥饿使鱼体水分和灰分含量升高,脂肪和蛋白质含量下降,且脂肪损失率高于蛋白质损失率,实验结束时,各组鱼体生化组成均恢复到对照组水平,表明在饥饿期间,卵形鲳鲹幼鱼主要消耗的能量物质为脂肪。     

Digestibility of feed ingredients in Florida pompano,Trachinotus carolinus adapted to either sea water or low salinity

Seven potential feed ingredients were evaluated for digestibility with Florida pompano Trachinotus carolinus using extruded diets. Ingredients included Special Select^? menhaden meal, fishery processing by‐product (Montlake meal), NuPro^® yeast extract, canola protein concentrate, corn protein concentrate, barley protein concentrate and Spirulina. Digestibility values were determined when fish were held at 3 and 28 g L^?1 salinity to determine the effect of salinity on digestibility. With the exception of the canola protein concentrate, the coefficients were numerically higher in pompano held at 28 g L^?1. No significant differences were detected for apparent crude protein or apparent energy digestibility between the two salinities. Amino acids were highly available from the two marine‐based ingredients and the barley and canola concentrates. The availability of alanine, leucine, isoleucine and phenylalanine was significantly higher (P < 0.05) from the barley protein concentrate at 28 g L^?1 than 3 g L^?1 salinity. Methionine and phenylalanine were highly available from all the ingredients except the yeast protein. Conversely, glycine was not well utilised from any of the ingredients. The apparent digestibility coefficients provided here allow for more precise formulation of diets for Florida pompano reared in both seawater and low‐salinity environments.     

延迟投饵对卵形鲳鲮早期仔鱼阶段摄食、成活及生长的影响

利用人工繁殖产生的卵形鲳够（Trachinotus ovatus）初孵仔鱼，在水温（26．8±1．4）℃、盐度28．2±0．8条件下，对延迟投饵0～6d的卵形鲳够仔鱼的摄食、生长及其成活情况进行了研究。结果显示，仔鱼于3Et龄开口，于开口的当天投饵及延迟投饵1、2、3、4和5d，投饵后2h内仔鱼的摄食率分别为15％、30％、50％、25％、15％和5％，每尾鱼的平均摄食量分别为0．4、0．6、1．3、0．6、0．3和0．1个轮虫。延迟投饵6d一组仔鱼的摄食率均为0。延迟投饵0、1和2d各组仔鱼的成活率相差不大，但延迟3d以上仔鱼的成活率急剧下降。卵形鲳鲣仔鱼的初次摄食饥饿不可逆点（PNR）出现在仔鱼开口后4d，开始投喂饵料的最佳时期应在仔鱼开口后的3d之内。     

卵形鲳鲹碱性磷酸酶和酸性磷酸酶的分布及其低温保存

测定了卵形鲳鲹（Trachinotus ovatus）的碱性磷酸酶（AKP）和酸性磷酸酶（ACP）在不同器官和肌肉中的活性;将样品分别置于4℃、-20℃和-80℃下保存3 d、7 d、15 d和30 d,研究不同保存温度和保存时间对样品中AKP和ACP酶活性的影响。结果表明,在卵形鲳鲹胃中未检测到AKP活性,其他器官中均检测到AKP活性,AKP活性大小顺序依次为后肠〉幽门盲囊〉肾〉中肠〉肝〉前肠〉心〉肌肉;ACP在卵形鲳鲹体内分布较广,所测器官中均有ACP活性,其活性大小顺序为肝〉肌肉〉后肠〉中肠〉幽门盲囊〉肾〉心〉前肠〉胃。低温保存试验结果表明,AKP和ACP在4℃和-20℃下保存,时间越长,活力越低;在-80℃下保存,AKP和ACP活力在30 d内基本稳定,只有幽门盲囊的AKP和ACP在长时间保存后活力明显下降。