长江口中华鲟幼鱼血液水分、渗透压及离子浓度的变化规律

为了研究长江口中华鲟幼鱼盐度适应过程及其调节规律,将7月龄幼鱼直接转入0(淡水对照),5,10,15等4个盐度组中养殖32天,分别在0.5,1,2,4,8,16,和32 d 检测幼鱼血液水分、血清渗透压和血清Na 、Cl-、K 的浓度,结果显示：试验过程中,淡水和盐度5组中华鲟幼鱼血液各项指标始终保持一致,未呈现显著性差异。盐度10和15组,中华鲟幼鱼血液水分含量呈先下降后上升趋势,下降程度与盐度呈正相关,16 d时各组幼鱼血液水分无显著性差异。中华鲟幼鱼转入盐度10和15条件下,其血清渗透压与Na 和Cl-浓度的变化趋势一致,表现为先上升后下降,最后达到新的平衡;12 h是其上升和下降的拐点。而血清K 浓度的变化趋势与血清渗透压和Na 、Cl-离子不同,呈现先下降后趋于平稳的趋势。从结果可以看出,中华鲟幼鱼与其他广盐性鱼类一样,其盐度适应过程可分为2个阶段,即临界期和调整期。     

盐度对银鲳血清渗透压、过氧化氢酶及鳃离子调节酶活力的影响

将银鲳幼鱼置于盐度14、25、36的海水中96 h,检测不同盐度下银鲳幼鱼血清渗透压、过氧化氢酶(CAT)以及鳃泡膜质子泵(VHA)、Ca² -ATP酶、碳酸酐酶(CA)活力随着时间推移而变化的情况。结果显示,血清渗透压变化和盐度呈正相关,并出现波动变化,变化范围为271～379 mOsm/kg,96 h时各盐度组血清渗透压均有恢复正常的趋势。高盐度(36)和低盐度(14)组CAT活力都显著升高而后逐渐恢复(P<0.05),盐度36组8 h时为各值中的最高点。鳃VHA活力变化:盐度14组先上升后回落,对照组基本保持平稳,盐度36组先下降而后恢复。盐度改变后,Ca² -ATP酶活力都出现显著增强(P<0.05),盐度14组比盐度36组的变化趋势更明显。盐度14和36组CA活力都出现显著增强(P<0.05),其中盐度36组24 h时为最高值。分析实验数据发现,血清渗透压与鳃VHA活力呈极显著负相关,与CA活力在低盐度适应时呈极显著负相关(P<0.01),而盐度14组血清渗透压与Ca² -ATP酶的变化呈基本相反趋势。结果表明,银鲳幼鱼在适应不同盐度时,血清渗透压会伴随盐度升降而改变,并激活CAT,而鳃VHA、Ca² -ATP酶、CA在渗透压调节过程中有重要作用。     

鲢鳙占优势的千岛湖浮游动物群落结构特征及其与环境因子的相关性

为了解以鲢鳙占优势的千岛湖中浮游动物群落结构特征以及与水温、溶解氧等环境因子的关系,采用方差分析、典范对应分析等方法,对千岛湖河流区、过渡区、湖泊区3个地区的浮游动物种类、数量以及环境因子的月变化特征进行了调查。结果表明:2007—2008年,共鉴定出浮游动物115种,其中原生动物16种、轮虫51种、枝角类23种、桡足类25种。浮游动物密度在春季(2007年:840.9/L,2008年:850.5/L)形成高峰;生物量在春季(2007年:1.89mg/L,2008年:0.837 mg/L)和秋季(2007年:1.63 mg/L,2008年:0.802 mg/L)形成双高峰;现存量从河流区至湖泊区依次递减。河流区和过渡区的浮游动物密度均于4 m水层达最大值,湖泊区于8 m水层达到最大值。各位点4～12 m水层的大型浮游甲壳动物优势种透明溞、蚤状溞、球状许水蚤等和小型浮游甲壳动物优势种长额象鼻溞、颈沟基合溞、台湾温剑水蚤等的生物量较高。原生动物、桡足类生物量与溶解氧显著正相关;轮虫、枝角类生物量与总氮、硝态氮、浮游植物生物量极显著正相关。典范对应分析(CCA)表明,溶解氧、温度、总氮、总磷、硝态氮是影响浮游动物时空分布的主要因子。透明溞在2—6月份主要受到以浮游植物为食物的上行效应的影响较大,而其他月份主要受水温的影响较大。     

增加饲料中Vc质量分数对银鲳血清溶菌酶活性及组织抗氧化能力的影响

研究了增加饲料中维生素C（VC）质量分数对银鲳（Pampus argenteus）血清溶菌酶活性及组织抗氧化能力的影响.以鱼粉、虾粉为蛋白源,鱼油为脂肪源配制VC质量分数分别为104.21 mg·kg^-1、455.33 mg·kg^-1和800.54 mg·kg^-1的3组饲料,依次编号为C1（对照组）、C2、C3.每组饲料设3个重复,投喂平均体质量为（6.18±0.15）g的银鲳幼鱼9周.结果显示,随着饲料中VC质量分数的增加,血清溶菌酶活性逐渐升高,C3组较C1、C2组溶菌酶活性显著性升高（P＜0.05）.增加VC质量分数可显著提高组织中的超氧化物歧化酶（SOD）活性及总抗氧化能力（T-AOC）（P ＜0.05）,但VC对不同组织中SOD活性的影响程度并不相同.随着饲料中VC质量分数的增加,肝脏与肌肉中VC水平显著性升高（P＜0.05）.同时,高水平VC也显著降低了组织中丙二醛（MDA）的质量摩尔浓度.分析表明,增加饲料中VC质量分数（大于455.33 mg·kg^-1）可提高银鲳血清溶菌酶活性与组织抗氧化能力,降低组织中的脂质过氧化反应.     

Evaluation of Mixed-Feeding Schedules with Varying Dietary Protein Content on the Growth Performance and Reduction of Cost of Production for Sutchi Catfish,Pangasius hypophthalmus (Sauvage) with Silver Carp,Hypophthalmichthys molitrix (Valenciennes)

Abstract

An on-station pond trial was conducted for 6 months to investigate the suitability of mixed-feeding schedules with varying protein levels on the growth of sutchi catfish, Pangasius hypophthalmuswith silver carp, Hypophthalmicthys molitrixwith a view to minimizing the cost of production. Five different feeding regimes employed were: high protein diet (30% protein, H), low protein (15% protein, L), one day low protein diet followed by one day high protein diet (1L/1H), 7 day low protein diet followed by 7 day high protein diet (7L/7H), and 14 day low protein diet followed by 14 day high protein diet (14L/14H). Ten experimental ponds each of 0.008 ha size were divided into 5 treatment groups each with two replicates. Fishes were stocked at the ratio of 80:20 (sutchi catfish:silver carp) at the total rate of 25,000/ha. Feeding rate was calculated only on the basis of sutchi catfish weight only and fish were fed at the rate of 15,10, 8, and 5% of their body weight for 1st, 2nd, 3rd months, and the rest of the experimental period, respectively. The ranges of water quality parameters during the study period were: temperature 22°C to 32.8°C, dissolved oxygen 4.30 to 7.44 mg/L, pH 6.85 to 7.50, and transparency 21.9 to 32.2 cm. The result of the study showed that significantly (P < 0.05) higher fish weight gain was achieved in feeding schedules of H and 1L/1H and lowest with 14L/14H. The feed conversion ratio (FCR) values ranged between 2.06 and 2.51 with H and 1L/1H showing significantly the best FCR. The FCR values were very low when weight of silver carp was considered which ranged between 1.58 and 1.68. The survival (%) of sutchi catfish were lower (78.1 to 82.5%) compared to that of silver carp (90–95%). The total production of sutchi catfish ranged between 3594 and 7095 kg/ha and silver carp ranged between 1777 and 2220 kg/ha. A simple economic analysis showed that fish in 1L/1H fed alternately with low and high protein diets resulted in the highest net profit. The result of the study suggest that for profitable sutchi catfish farming in Bangladesh, farmers can adopt a mixed-feeding schedule of alternated low and high protein diet instead of continuously feeding a high protein diet.     

Gel Properties of Surimi from Silver Carp (Hypophthalmichthys molitrix): Effects of Whey Protein Concentrate,CaCl2, and Setting Condition

The effects of setting time, whey protein concentrate (WPC), and calcium chloride (CaCl₂) on textural properties of silver carp surimi were investigated. Response surface methodology was used to evaluate and compare the effects of setting time (30–90 min), WPC (1–9% of protein ratio), and CaCl₂ (1–59 mmol/kg) on the gel strength. Models for breaking force, breaking distance, and gel strength of surimi gel were established. The maximum gel strength was achieved at the setting time of 60 min, WPC and CaCl₂ at 5% protein ratio, and 15–18 mmol/kg. CaCl₂ was the most significant factor affecting the gel strength.     

鲢鱼骨胶原多肽螯合钙的制备研究

文章探讨了以鲢（Hypophthalmichthysmolitrix）鱼骨为原料,采用风味蛋白酶酶解制备骨胶原多肽水解液,剩余骨渣经乳酸提取制备骨粉酸解液（钙液）,研究其通过螯合制备鲢鱼骨胶原多肽螯合钙的工艺条件。分析了酶解时间对鲢鱼骨蛋白酶解产物产品品质和功能特性（溶解性和热稳定性）的影响以及采用乳酸提取鲢鱼骨中钙时提取温度对钙溶出率的影响,并以螯合率为指标,考察pH、时间、温度和多肽液与钙液体积比对螯合反应的影响。结果表明,在温度50℃,按原料鱼排质量0．09％加入风味蛋白酶酶解30min制备出的鲢鱼骨胶原多肽具有良好的产品品质和功能特性;乳酸提钙时提取温度对钙溶出率没有显著性影响（P〉0．05）;在pH8、温度25℃条件下,多肽液与钙液体积比1：1反应40min得到的鲢鱼骨胶原蛋白螯合钙螯合率最高（85．24％）。     

Utilization of wastewater-grown zooplankton: Nutritional quality of zooplankton and performance of silver perch Bidyanus bidyanus (Mitchell 1838) (Teraponidae) fed on wastewater-grown zooplankton

Zooplankton grow in the last stage of water purification at the Werribee Sewage Treatment Lagoons (WSTL) and the resource is huge and unutilized. Daphnia carinata and Moina australiensis are the dominant species at the WSTL. The protein content of D. carinata and M. australiensis was 54.80% and 64.80%, respectively. Analysis of zooplankton showed that both essential and nonessential amino acids were present at a level that was higher than control diet. Silver perch fed on D. carinata exhibited better growth, better food conversion ratio (FCR), protein efficiency ratio (PER) and apparent net protein utilization (ANPU), which were not significantly different from the control diet ( P  > 0.05). Heavy metals concentrations were at very low levels in fish fed on wastewater-grown zooplankton.     

金属离子对红白锦鲤肠及肝胰脏蛋白酶活性的影响（摘要）（英文）

[目的]研究金属离子对红白锦鲤消化组织蛋白酶活性的影响。[方法]以酶学分析方法研究4种金属离子（Na＋、K＋、Ca2 ＋、Mg2 ＋分别来源于NaCl、KCl、CaCl2.2H2O、MgCl2.6H2O,浓度梯度均设置为25、50、75、100、125、150 mmol/L）对红白锦鲤肝胰脏、前肠、中肠、后肠蛋白酶活性的影响。蛋白酶活性的测定采用福林-酚显色法,用Thermo紫外分光光度计,根据OD680计算蛋白酶活性,以1 min水解酪蛋白产生1μg酪氨酸为一个酶活力单位,记为μg/（min.g）。[结果]在设定的浓度范围内（25 ～150 mmol/L）,4种金属离子对蛋白酶活性影响不同。K＋对肝胰脏和后肠的蛋白酶活性有不同程度的促进作用,其中K＋对中肠表现为低浓度促进,高浓度抑制的作用,对前肠蛋白酶表现为抑制作用;Na＋对肝胰脏、前肠和后肠的蛋白酶表现为不同程度促进作用,对中肠表现为抑制作用。Mg2 ＋、Ca2 ＋对肠及肝胰脏的蛋白酶均表现为不同程度的抑制作用。试验所选用的K＋、Na＋、Mg2 ＋、Ca2 ＋均属矿物元素,其中添加浓度25 mmol/LK＋对锦鲤肠蛋白酶活性促进作用最大;浓度150 mmol/L Na＋显著提高后肠和肝胰脏蛋白酶活性。这些浓度可作为饲料添加剂中的参考用量。Mg2 ＋、Ca2 ＋对锦鲤各消化器官（中肠除外）的抑制作用随浓度的增加蛋白酶活性降低,但考虑该元素系水产动物生长发育所必需,因此可选用低浓度或螯合物进行添加,以提高酶的生物学效价,提高饲料中蛋白的利用率,降低饵料系数,节约蛋白。[结论]该研究可为红白锦鲤消化生理的研究以及配合饲料的开发、优化提供基础数据和理论依据。     

不同外源激素组合对银狐繁殖力的影响

为了研究不同外源激素组合对银狐繁殖力的影响,随机选择健康母银狐50只,分为4个试验组和1个对照组,每组10只。在母狐排卵的前10 d开始对4个试验组注射外源激素,每组注射两种激素（第1激素和第2激素）,每组的第1激素和第2激素有所不同;对照组母狐按常规方式饲养管理。结果表明,试验1组（PMSG+HCG激素组）平均产仔数比对照组多1.3只/母,差异极显著（P＜0.01）;试验4组（FSH+LH激素组）平均产仔数比对照组多0.9只/母,差异显著（P＜0.05）;试验2组（三合激素+LRHA3激素组）、试验3组（LRHA3+LRHA3激素组）平均产仔数与对照组间无显著差异（P＞0.05）;试验1组与试验2、3组间差异显著（P＜0.05）,而与试验4组间差异不显著（P＞0.05）;试验2、3、4组间差异不显著（P＞0.05）。通过性价比对比,PMSG+HCG激素组合的性价比（0.078）为最高;而另外3组激素组合的性价比均较低。综上所述,PMSG+HCG激素组合平均产仔数多、激素性价比高,应用效果显著。