胶州湾鱼类生物量粒径谱特征

为了解胶州湾海域鱼类群落粒径结构特征,本研究根据2016-2017年4次底拖网调查数据构建了胶州湾鱼类生物量粒径谱,比较分析了各季节鱼类生物量粒径谱特征参数的异质性。结果显示,胶州湾Sheldon型鱼类生物量粒径谱呈现单峰模式,鱼类粒径范围为-3~10粒径级,粒径分布相对均匀,且峰值位于5~6粒径级,主要由大泷六线鱼和褐菖鲉等小型鱼类构成。各季节鱼类标准化生物量粒径谱曲率和曲度差异显著,其中春季曲率最大且曲线较平缓,夏季曲率最小且曲线相对陡峭。谱线曲度和曲率的季节变化主要与粒径小的细纹狮子鱼、大泷六线鱼、玉筋鱼及长丝虾虎鱼等地方常栖性种类和赤鼻棱鳀、白姑鱼等季节洄游性种类的出现有关。Abundance-biomass comparison(ABC)曲线表明,春季处于未干扰状态,冬季处于中度干扰状态,夏秋季处于严重干扰状态。研究表明,胶州湾鱼类群落总体处于严重干扰状态,鱼类生物量谱呈现单峰型,粒径结构以小型粒径鱼类为主,且地方常栖性和季节洄游性鱼类等补充群体的数量和粒径大小影响鱼类生物量粒径谱的峰型和曲率。     

微生物对鱼粉中组胺含量的影响研究

我国鱼粉产品质量参差不齐,由于原料问题组胺含量普遍高于国际先进水平,过高的鱼粉含量易造成食品安全问题。为了降低过高的组胺含量对鱼粉品质的影响,本实验通过使用微生物参与降解鱼粉产品中的组胺。实验将降解时间与微生物添加比例作为变量,测试出较为适宜微生物降级组胺的条件,以及该条件下的实际效果。实验结果表明在设置的6个时间中(以6小时为时间梯),24h为较适宜的降解时间；在较适宜的降解时间中(24h)较适宜的微生物添加比例为10:1。此时鱼粉组胺含量为1622mg/kg,相较未加入微生物处理的鱼粉组胺含量(5298 mg/kg)降低69%。实验结果证明了微生物处理鱼粉中组胺具有显著的效果,为鱼粉生产、储存技术的改良提供了参考依据。     

鱼蟹稻田飞虫捕食装置风光互补供能系统的研究

针对鱼蟹稻田飞虫捕食装置的离网型户外供能需求的问题，着重研究该装置的供能系统方案。基于户外供能合理性要求，采用小型风力发电机和太阳能电池板自主互补发电来进行能源供应；对小型风力发电机和太阳能电池板分别进行Matlab/Simulink建模，着重对叶轮的风能利用系数、叶尖速比和桨距角的相关性进行量化分析，利用单因素分析法对太阳能电池板进行分析；在桨距角确定的条件下，适当取值叶尖速比，能够获得最大风能利用系数。同时，在不同温度和辐射的条件下，太阳能电池板能够取得功率曲线的峰值，为风光互补的最大功率获取提供理论上的支持。针对离网型风光互补系统能源的合理化利用，提出混合供能的能量管理策略，符合该装置的供能需求，对户外同类型装置供能设计提供一定的参考。     

泸沽湖省级自然保护区鱼类物种多样性调查研究

为对泸沽湖省级自然保护区的生物多样性及环境质量做出更好的评估,分别于2016年3月,6月,7月就其鱼类资源特点及其分布格局等开展了3次调查。结果表明,泸沽湖省级自然保护区记录鱼类6目8科15属17种,鲤形目鲤科鱼类种数最为丰富,共9种,占泸沽湖鱼类总种数的52.9%;土著鱼类仅2属4种,分别为泥鳅、厚唇裂腹鱼、宁蒗裂腹鱼、小口裂腹鱼。区系组成与云贵高原湖泊存在共同特点:种类贫乏,个体较小,生长稍慢。泸沽湖鱼类物种多样性匮乏、物种同域分化现象明显、鱼类特有性极强、物种群落脆弱性极高、物种组成自然性偏低。文中提出保护好鱼类产卵场,加强入湖河流的清淤治理,建立保育繁殖基地等保护策略。     

Boom‐bust like dynamics of invasive black bullhead (Ameiurus melas) in Lake Sava (Serbia)

The life‐history traits and population dynamics of the black bullhead Ameiurus melas (Rafinesque) were studied monthly from August 2009 to December 2012 in Lake Sava in Belgrade (Serbia). This period included a mass mortality event in May 2011 and subsequent population recovery during 2012. Available evidence suggests the mass mortality was caused by European catfish virus that only affected the black bullhead. Changes in key life‐history traits and the recovery potential (increase in catch‐per‐unit‐effort, doubling of young‐of‐the‐year to adult ratio, earlier maturation and increased fecundity) following the mass mortality event suggest population resilience typical of a recurring boom‐bust pattern and demonstrate the species’ capacity to recover rapidly and re‐establish following disturbance. Repeated systematic mass removals of both juveniles and adults (using fyke nets) will be required if future fishery management measures aimed at limiting the population size are to be effective.     

蛋白酶解对鲣鱼肉乳化特性的改善

天然鱼蛋白乳化性不佳,难以满足实际生产需求,但鱼蛋白的酶解改性可改善其功能特性,并拓展应用范围。以鲣鱼白色肉为原料,以水解度和乳化性为主要指标,比较了不同蛋白酶(胰蛋白酶、风味蛋白酶、木瓜蛋白酶)和水解时间对酶解液制备和鱼蛋白乳化性的影响,优化了酶解工艺参数。将鱼蛋白进行冷冻干燥后,分析鱼蛋白酶解前后溶解性、乳化性和起泡性等功能特性的差异。结果表明,当胰蛋白酶添加量2 000 U·g^-1,酶解10 min时,鱼蛋白水解度(DH)达到8.2%,此时鱼蛋白乳化特性最佳。与酶解前样品相比,酶解后鱼蛋白的乳化活性和乳化稳定性显著提高,其溶解度、起泡性和起泡稳定性均有一定程度的改善。酶解制备的鲣鱼蛋白在广泛pH范围内具有更好的功能性质,在食品工业具有更高的应用价值。     

Potential of indigenous Bacillus spp. as probiotic feed supplements in an extruded low‐fish‐meal diet for juvenile olive flounder,Paralichthys olivaceus

A 12‐week feeding trial was designed to assess the probiotic potential of indigenous Bacillus amyloliquefaciens and/or Bacillus subtilis singly or in combination with Bacillus licheniformis in an extruded feed for olive flounder (Paralichthys olivaceus) juveniles. A high fish meal (FM) diet (control) and a low‐FM diet containing an alternative protein blend (30% FM replacement, FM30) were formulated. Three other experimental diets were prepared by inclusion of B. amyloliquefaciens (BA), B. subtilis (BS), or a mixture of B. amyloliquefaciens, B. subtilis, and B. licheniformis (BASL) into FM30 diet, with a final concentration of 10⁶ CFU/g diet. Results indicated that the FM30 diet was well tolerated by flounder, and the overall performance was not affected by dietary treatments. Lysozyme activity and total immunoglobulin level were significantly reduced in flounders when fed with the FM30 diet compared with the BASL and BA diets, respectively. The Bacillus additives neither enriched the relative abundance of the corresponding Bacillus spp. in the relevant gut microbiota of olive flounder nor modulated the presumptive gene functions of the gut microbiome. Despite the absence of growth‐promoting effect, the tested probiotics could still be economically viable for use as immunostimulants in commercial flounder diets with partial FM replacement.     

基于主成分分析的吸鱼泵对鱼类损伤评价方法

采用主成分分析法建立吸鱼泵的损伤综合评价方法,为吸鱼泵的研究与改进提供装备技术参数。使用真空吸鱼泵对鲫鱼进行吸捕试验,获取鱼体损伤数据。通过测定体表损伤面积比率、24 h存活率、红细胞数量、白细胞数量、超氧化物歧化酶(SOD)活力、谷丙转氨酶(ALT)活力、肌酐(Cr)含量等多个关键指标值,采用主成分分析法进行相关性分析,建立损伤综合评价模型。结果显示：采用主成分分析法提取出3个主成分的累积贡献率达到78.232%,可反映出鱼体损伤的大部分情况;损伤评价综合评价模型：F=0.285X₁+0.111X₂+0.316X₃+0.366X₄-0.118X₅+0.234X₆,真空吸鱼泵对鱼的体表和内脏无显著损伤情况,综合得分-0.102,与对照组接近,表明真空吸鱼泵对鱼的损伤影响很小。研究表明,SOD活力、白细胞数和体表损伤面积比率是对损伤评价影响较大的数据指标,采用主成分分析法建立的综合损伤评价模型可以作为评价鱼损伤情况的一种可行方法,为吸鱼泵的改进研究提供了有力参考。     

Evaluation of dietary inclusion of housefly maggot (Musca domestica) meal on growth,fillet composition and physiological responses for barramundi,Lates calcarifer

The study was to evaluate the effects of dietary fish meal (FM) partially replaced by housefly maggot meal (HMM) on growth, fillet composition and physiological responses of juvenile barramundi, Lates calcarifera. HMM at 100, 150, 200 and 300 g kg^?1 was supplemented in the basal diet to replace dietary FM protein. Basal diet without HMM supplementation was used as control. Total of five experimental diets were fed to triplicate groups of juvenile barramundi (initial weight: 9.66 ± 0.22 g) in a flow‐through rearing system for 8 weeks. Fish fed all experimental diets showed no effects (P > 0.05) on weight gain and whole body protein, lipid and moisture content. Fish fed control diet and 100 g kg^?1 HMM diet had the highest (P < 0.05) hepatic superoxide dismutase (SOD) activity, followed by 150 g kg^?1 HMM group, the lowest in 200 and 200 g kg^?1 HMM groups. Hepatic thiobarbituric acid reactive substance (TBARS) value was the highest in fish fed 150–300 g kg^?1 HMM diets, followed by 100 g kg^?1 HMM group and the lowest in fish fed the control diet. Fish fed the 300 g kg^?1 HMM diet had lower plasma lysozyme activity than fish fed other diets. The results indicated that up to 300 g kg^?1 HMM can be used to substitute dietary FM protein without negative effect on growth. Although physiological responses were also considered, up to 100 g kg^?1 HMM in barramundi diet was recommended.