Inclusion of blue mussel extract in diets based on fish and soybean meals for tiger puffer Takifugu rubripes

Inclusion of the water-soluble fraction of blue mussels Mytilus galloprovincialis as a feed additive was examined with tiger puffer Takifugu rupbripes. The control diet mainly consisted of fish meal, potato starch, and pollack liver oil. Experimental diets were formulated to replace 30% and 40% of the fish meal protein with defatted soybean meal (SBM), and were supplemented with 0–20% mussel extracts. Fish of 18 g initial body weight were fed each diet to satiation, twice daily, 6 days per week for 7 weeks at 20°C. Weight gain and protein efficiency ratio of fish fed the diet containing SBM without the extract were significantly lower than those of the control at the 30% replacement level. Addition of 5% or 10% extract improved the growth and feed utilization to levels comparable to those of the control. At 40% substitution, statistically identical growth and feed performance to the control were obtained for diets supplemented with 10% or 20% extract; however, performance for 5% addition was significantly lower. Thus, the water-soluble fraction of blue mussels would be an effective feeding stimulant in aquaculture feed for tiger puffer that makes it possible to replace 30–40% of fish meal protein with SBM.     

暗纹东方鲀仔幼鱼的形态、摄食与生长的初步研究

作者于1995、1997年对暗红东方鲀（Takifuguobscurus）仔幼鱼的形态发育、摄食特征以及生长进行了观察和研究。结果表明：1．尾鳍条和体部斑纹的形成可用来区分仔鱼期、稚鱼期和幼鱼期;2当稚鱼出现叨食食物碎片行为时,预示消化器官发育已趋完备．开始进入幼鱼期,要及时采取措施,以防同类相残;3．河鲀度生长方程为L＝3．58e~(0.0519t),在8日龄和30日龄生长速度和加速度明显增大,其生长与消化器官的机能有密切关系。     

饲料中淀粉和糊精对红鳍东方鲀生长和低氧耐受性的影响

在水产养殖鱼粉鱼油供应相对紧缺的背景下,充分挖掘碳水化合物(糖类)的营养功能具有重要意义。低氧是水产养殖中一种常见的环境应激。大量研究表明,鱼类在低氧条件下主要利用糖来提供能量,但饲料糖源对红鳍东方鲀(Takifugu rubripes)的生长和急性低氧耐受性尚未见报道。本研究分别在饲料中添加玉米淀粉或糊精(玉米淀粉水解物)作为糖源,养殖8周后,测定生长、急性低氧存活率、代谢产物和低氧诱导因子(HIF)信号通路等指标。结果显示,与淀粉组相比,糊精虽然不会影响红鳍东方鲀的生长性能和鱼体成分,但显著提高了其在急性低氧条件下的存活率。在常氧条件下,淀粉组和糊精组肝脏的糖原和乳酸含量均无显著差异(P>0.05),但在低氧条件下,糊精组肝脏的乳酸含量和乳酸脱氢酶基因表达量均显著高于淀粉组(P<0.05)。同时,糊精组肝脏hif-1α (hypoxia inducible factor 1 subunit alpha)和hif-3α (hypoxia inducible factor 1 subunit alpha, like)、肌肉hif-1α和vegfa (vascular endothelial growth factor A)的表达量均显著高于淀粉组(P<0.05)。在低氧条件下,糊精组血清甘油三酯(TG)含量显著升高,但淀粉组血清和肝脏的TG含量在低氧后却显著下降(P<0.05)。与常氧组相比,糊精组在低氧后的肌肉总蛋白含量、肝脏蛋白激酶B (v-akt murine thymoma viral oncogene homolog 1, akt1)和哺乳动物雷帕霉素靶蛋白(mechanistic target of rapamycin kinase, mtor)基因表达量均显著降低,但淀粉组肝脏的mtor基因表达在低氧后却显著升高(P<0.05)。综上所述,用易消化的糊精替代玉米淀粉激活了HIF信号通路介导的无氧糖酵解来为鱼体提供更多的能量,同时还可以抑制脂肪的分解和蛋白质的合成,减少了O2的消耗,从而提高了红鳍东方鲀对急性低氧的耐受性。本研究结果为鱼类耐低氧饲料的设计和健康养殖提供了重要参考。     

基于模糊数学感官评价的发酵河鲀鱼肠工艺优化

河鲀肉质鲜美、营养丰富,多以鲜食为主,为延长河鲀产品货架期,丰富河鲀产品种类,实验以暗纹东方鲀为原料,利用发酵技术研制河鲀鱼肠。采用戊糖片球菌、植物乳杆菌、木糖葡萄球菌作为发酵剂,利用单因素实验和模糊数学综合评价法确定辅料配方,通过正交试验设计对发酵条件进行优化。结果显示,发酵河鲀鱼肠的最优辅料配方按葡萄糖3%、食用盐2%、马铃薯淀粉10% (均为质量分数),最佳发酵条件为接种量3.5%、发酵时间10 h、发酵温度35 ℃,最优发酵条件下的感官评价得分为79.70分。本研究建立了基于模糊数学的感官综合评价方法,确定了发酵河鲀鱼肠的最佳配方和发酵条件,为开发发酵河鲀产品提供了一定的理论依据。     

体重对暗纹东方鲀摄食影响的研究

利用室内养殖实验研究了暗纹东方鲀的体重与摄食率的关系以及其日粮的变化规律。结果表明,随着体重由12．3g增加到213．2g,摄食率由12．6％下降到2．6％,由于暗纹东方鲀属于偏肉食性鱼类,其日粮变化一般以2天为一个周期呈振荡型变化。     

3种肉食性鱼类的捕食及脊尾白虾防御行为比较

通过对黑鲷、漠斑牙鲆及暗纹东方鲀3种肉食性鱼类捕食脊尾白虾的行为观察。结果发现,3种肉食性鱼捕食脊尾白虾的强度排列依次为黑鲷暗纹东方鲀漠斑牙鲆。脊尾白虾最主要的防御方式为尾扇拨水向后弹开。