乌贼内壳中β-壳聚糖的制备研究

本文研究了用乌贼内壳制备β-甲壳素和壳聚糖,结果乌贼内壳背楯提取甲壳素的最佳条件为:先用1.5 mol/L HCl浸24 h,再用1.5 mol/LNaOH于80℃浸3 h。产率为3.55％。从乌贼内壳周缘提取甲壳素的最佳条件为:先用1.5 mol/LHCl浸24 h,再用1 mol/L NaOH75℃浸3 h,产率为30％;产品用IR和XRD表征。实验结果还表明,加入相转移催化剂可提高β-壳聚糖的脱乙酰度。     

甲壳低聚糖的酸水解

不同浓度（2、3、4、6mol/L）HCl）对壳聚糖、低聚氨基葡萄糖、氨基葡萄糖单糖的降解实验表明，在100℃并有氩气保护的条件下，HCl在水解氨基葡萄糖聚糖的同时对所生成单糖的分子结构有较强的破坏作用，2、3、4、6mol/L的HCl所破坏的氨基葡萄糖分子数N与HCl浓度C HCl和水解时间t之间的关系遵循方程：N=0.0854C HCl t。氨基葡萄糖的回收率y'对HCl浓度及分解时间的方程为：y'=-0.0854 C HCl t 100。HCl降解聚氨基葡萄糖的动力学反应受HCl浓度和底物聚合度的影响，生成单糖的产率随水解时间延长、HCl浓度增大而增加，但在相同HCl浓度和水解时间条件下，聚合低则降解进程快。6mol/LHCl于100℃水解3h对氨基葡萄糖分子结构没有显著的破坏作用，回收率为99.4％，但对低聚氨基葡萄糖、壳聚糖的水解产率均很低，分别为33.6％、33.2％。本研究结果证明，壳聚糖较好的分解条件为HCl浓度4mol/L、水解72h，此时单糖水解产率可达89.6％。     

氨基葡萄糖盐酸盐的制备

对利用甲壳素为原料制备氨基葡萄糖盐酸盐的工艺进行了研究，得到最佳工艺条件为：采用3．5h的水解时间；在90℃进行水解；盐酸的浓度为36％；甲壳素与盐酸的质量百分比为1：6：盐酸的回收率为60％。在此最佳工艺条件下得到的氨基葡萄糖盐酸盐经瓜确认，最高产率可达36％。生物测定表明，产品氨基葡萄糖盐酸盐对大肠杆菌等菌种有一定的抑菌活性。     

响应曲面法优化麒麟菜卡拉胶碱处理工艺

采用响应曲面法研究了碱液质量浓度、浸泡时间和浸泡温度对麒麟菜（Eucheuma）卡拉胶的凝胶强度和产率的影响。在单因素试验基础上采用Box—Benhnken中心组合试验，以碱液质量浓度、浸泡时间和浸泡温度为影响因素，以凝胶强度和产率为响应值建立二次回归方程，通过响应面分析得到优化组合。结果显示，碱处理优化工艺参数为碱液质量浓度250g·L-1、浸泡时间3．5d和浸泡温度25℃，在此条件下提取的麒麟菜卡拉胶凝胶强度为721g·cm-2（质量浓度10g·L-1），产率为35．17％。     

茜素红S对异齿裂腹鱼稚鱼标记效果研究

为探索茜素红S对异齿裂腹鱼稚鱼浸泡标记的适宜条件,采用半静态式水生生物急性毒性试验法确定茜素红S对异齿裂腹鱼稚鱼安全质量浓度,利用不同质量浓度的茜素红S溶液对45日龄的异齿裂腹鱼稚鱼浸泡不同时间,探究各试验组稚鱼死亡率、生长情况、标记效果和标记有效保存时间,确定茜素红S对异齿裂腹鱼稚鱼的适宜标记条件。试验结果表明：茜素红S对异齿裂腹鱼稚鱼24、48、72、96 h半致死质量浓度分别为225.85、147.72、139.21、137.66 mg/L,安全质量浓度为28.99 mg/L;0～125 mg/L的茜素红S溶液浸泡稚鱼24 h,质量浓度为75～125 mg/L稚鱼耳石标记效果可见,当茜素红S质量浓度为125 mg/L时,稚鱼死亡率显著升高(P<0.05);75 mg/L茜素红S浸泡稚鱼12～96 h,浸泡24～96 h稚鱼耳石标记效果可见,当浸泡时间为96 h时,稚鱼死亡率显著升高(P<0.05);在4个月的续养过程中,75 mg/L茜素红S溶液浸泡72～84 h, 4个月后稚鱼耳石标记效果依旧可见。综合生长、存活率、染色效果及标记保存时间,建议采用75 mg/L茜素...     

海带蛋白的提取和活性研究

采用5%NaOH、0.15 mol/L NaCl、0.1 mol/L磷酸盐缓冲液、0.15 mol/L NaCl及0.06%纤维素酶和1%SDS溶液提取新鲜海带中的蛋白质,并采用Brrddford的方法测定提取的蛋白质含量.结果表明,采用5%NaOH 0.06%纤维素酶浸泡,然后经超声波破碎,离心取上清液进行100%饱和度的(NH4)2SO4沉淀,对所得沉淀透析后冻干所得海带蛋白质的含量较多.时间飞行质谱表明蛋白质分子量为872～7705 m/z.抑菌试验表明海带蛋白对大肠杆菌、产气杆菌、金色葡萄球菌具有抑制作用.同时,以海带蛋白(5 mg/kg)对高血压模型大鼠灌胃具有良好的降压作用.     

四环素标记斑马鱼耳石效果及对抗氧化力的影响

为了研究四环素标记鱼类的效果及其对抗氧化能力的影响,设置100、150、250 mg/L浓度梯度的盐酸四环素(TCH)溶液和不同浸泡时间(18 h和24 h)对毒理实验常用对象斑马鱼(Danio rerio)进行浸泡标记,通过观察TCH浸泡标记后30 d内斑马鱼耳石的标记效果以及浸泡后第1、3、9、15 d时鱼体内三种抗氧化酶(SOD、CAT、GSH-Px)的活性变化,综合分析其标记鱼类的效果和安全性。结果显示,在150 mg/L和250 mg/L浓度的TCH溶液中浸泡18 h或24 h,斑马鱼耳石标记率可达100%,且耳石上可见清晰的黄色标记轮纹。浸泡18 h时,中高浓度组(150 mg/L和250 mg/L)斑马鱼的抗氧化酶活性在浸泡后的第3 d显著增加。浸泡24 h时,各浓度组的抗氧化酶活性在第1 d显著升高,250 mg/L浓度组的SOD和GSH-Px活性分别在第1 d和第9 d显著低于对照组,各组的抗氧化酶活性均在第15 d时恢复为对照组水平。结果表明,100 mg/L和150 mg/L浓度的TCH浸泡液对斑马鱼的抗氧化酶活性起诱导作用,250 mg/L浓度的TCH溶液浸泡,对其抗氧化酶活性产生了短期的抑制作用并可能对机体产生可恢复的氧化损伤。     

甲壳素、壳聚糖生产工艺研究

本文以虾壳为原料探讨了甲壳素、壳聚糖的最佳提取工艺。试验中利用稀氢氧化钠溶液除去虾壳中的粗蛋白质,稀盐酸溶液除去虾壳中的灰分,并通过单因素试验得出制备甲壳素的最佳工艺条件为:先用5.0%氢氧化钠溶液脱粗蛋白质,处理时间5h,然后用5.0%盐酸溶液脱灰分,处理时间3h,循环处理直至加酸无气泡产生,甲壳素得率为6.0%,色泽白度为50.3,灰分为2.0%。通过正交试验探讨出甲壳素脱乙酰制备壳聚糖的最佳条件为:氢氧化钠溶液浓度50%,温度90℃,时间12h,料液比1∶70。壳聚糖脱乙酰度(D.D%)为84.8%,粘度(浓度1%)为38.3mPa.s。     

大型海藻对氮磷吸收能力的初步研究

实验选取了经济价值较高、生态特征较为明显且研究较为深入的三种大型海藻:海带(Laminaria japonica Aresch)、鼠尾藻(Sargassum thunbergii)和龙须菜(Gracilaria lemaneiformis)作为实验材料,在模拟自然环境条件(14℃、1500lx)和适宜的氮、磷浓度(50μmol/L、5μmol/L)下,研究其在72h内对氮、磷的吸收能力。实验数据测得,海带、鼠尾藻和龙须菜对氨氮吸收速率分别为0.397μmol/g·h、0.317μmol/g·h和0.300μmol/g·h,吸收效率为66.3%、53.6%和51.2%;对磷的吸收速率分别为0.036μmol/g·h、0.030μmol/g·h和0.033μmol/g·h,吸收效率为65.2%、55.7%和58.8%。结果表明,三种海藻对氮、磷均有明显的吸收效果,吸收能力顺序为:海带>龙须菜>鼠尾藻。     

凡纳滨对虾下脚料生产甲壳素过程中盐酸的循环利用

为减少甲壳素生产过程中废酸液对环境的污染,降低甲壳素的生产成本,试验以甲壳素生产过程中的废盐酸为研究对象,利用硫酸和氯化钙反应进行回收、循环利用盐酸溶液,通过单因素试验和正交试验对工艺条件进行优化。结果表明,脱钙废盐酸溶液最佳再生条件:反应温度为室温,硫酸质量分数为98%,硫酸与废盐酸中钙离子的摩尔比为2.3∶1,反应时间13 min,静置时间3.5 h,最佳条件下盐酸再生率为91.51%。利用最佳工艺条件对废盐酸进行再生处理,盐酸可循环重复利用5次,脱钙虾壳的碳酸钙残留量≤1.2%。     

皱纹盘鲍维生素D营养需要的研究

在以酪蛋白和明胶为蛋白源的精制饲料中添加不同浓度梯度的维生素D,并以海带为对照组饲喂皱纹盘鲍幼鲍103d。结果表明:幼鲍的生长及软体部水分,脂肪和蛋白质含量受到饲料中维生素D添加水平的影响显著,但成活率不受饲料中添加水平的影响;饲料中适量添加维生素D可以提高幼鲍软体部碱性磷酸酶的活力,但饲料中缺乏或过高水平的维生素D导致幼鲍软体部碱性磷酸酶活力的降低;贝壳中灰分及钙、磷含量受饲料中维生素D添加水平的影响显著。以增重,蛋白质增量和软体部碱性磷酸酶的活力为指标,幼鲍饲料中维生素D的适宜含量为100IU·(100g)-1饲料。     

Effect of dietary substitution of sea tangle (ST), Laminaria japonica with rice bran (RB) on growth and body composition of juvenile abalone (Haliotis discus)

Dietary substitution effect of sea tangle (ST) with rice bran (RB) on growth and carcass composition of juvenile abalone (Haliotis discus) was determined. Juvenile abalone was acclimated to the experimental conditions for 4 weeks. Seventy juvenile abalone averaging 0.43 g were randomly distributed into each of the 18, 70 L plastic rectangular containers. The experimental diets were fed to abalone once a day at a satiation level with a little leftover. The feeding trial lasted for 16 weeks. Survival of abalone was not affected by dietary substitution of ST with RB. However, weight gain of abalone fed the RB40 diet was higher than that of abalone fed the all other diets except for the RB0 diet. No significant difference in weight gain was found in abalone fed between the RB0 and RB100 diets. SGR of abalone fed the RB40 diet was higher than that of abalone fed the all other diets. Also SGR of abalone fed the RB0 diet was higher than that of abalone fed the RB100 diet, but not different from that of abalone fed the RB20, RB60 and RB80 diets. Moisture, crude protein and ash content of the soft body of abalone were affected by dietary substitution of ST with RB. In conclusion, the 100% ST could be substituted with RB without a retardation of weight gain of abalone when the 20% ST was included into the experimental diet. However, the best growth performance was obtained in abalone fed the RB40 diet substituting 40% ST with RB.     

Effect of proline‐enriched abalone feed on selected metabolite levels of slow‐growing adult Haliotis midae

Abalone is currently considered South Africa's most successfully produced aquaculture export product, with a 76% share of the total value generated by the aquaculture sector. A major risk factor for this sector is slow growth rates experienced during farming. Abalone feeds are often supplemented with amino acids in an attempt to enhance abalone growth. This is a first investigation of the effect of added proline to standard abalone feed, on the metabolite profile of slow‐growing abalone. A targeted liquid chromatography tandem mass spectrometry metabolomics research approach was followed to recognise the metabolic response of abalone showing slower growth performance. The addition of proline to the standard abalone diet was found to serve as a substrate for amino acid catabolism in slower growing abalone, by means of proline breakdown to assist with energy production via the tricarboxylic acid cycle. Other amino acids and urea cycle intermediates, that is, arginine, asparagine, ornithine and creatine further support energy production via the action of protein catabolism in slow‐growing abalone. Additionally, the importance of understanding how abalone respond metabolically to modified feed highlights the use of metabolomics to answer abalone aquaculture farming questions.     

Feasibility of Offshore Co‐culture of Abalone,Haliotis discus hannai Ino,and Sea Cucumber,Apostichopus japonicus,in a Temperate Zone

Feasibility of offshore co‐culture of abalone and sea cucumber was investigated in Northern China. Survival and growth of abalone, Haliotis discus hannai Ino, and sea cucumber, Apostichopus japonicus, co‐cultured in abalone cages from suspended longlines, in the offshore area, were examined. Abalone and sea cucumbers were co‐cultured at density ratios of both 3:1 and 6:1 for 1 yr. Abalone were fed with fresh kelp and no additional feed was given to sea cucumbers. Survival of abalone and sea cucumber was 100% for all treatments. Abalone and sea cucumber grew well; the body weight (BW) of abalone and sea cucumber was nearly doubled and had reached a commercial size. There were no significant differences in the growth rates for both abalone and sea cucumber between the two density treatments. The specific growth rate of BW of abalone (SGRbw) was highest in June, with a value of 0.536%/d. Growth rate of sea cucumber (SGRsc) was highest in December, reached 1.84%/d, with an annual average SGRsc of 0.182%/d. Results suggested that the offshore co‐culture of abalone and sea cucumber was feasible offshore. The co‐culture of abalone with sea cucumbers may provide an additional valuable crop without additional financial input.     

Effects of dietary substitution of fishmeal with the combined dry microalgae,Nannochloropsis oceanica (NO) biomass residue and casein on growth and body composition of juvenile abalone (Haliotis discus)

The effects of dietary substitution of fishmeal with the combined dry Nannochloropsis oceanica (NO) biomass residue and casein on growth performance and carcass composition of juvenile abalone was determined. One thousand two hundred and sixty juvenile abalone were randomly distributed into the 18 L plastic rectangular containers. Five experimental diets in triplicate were prepared. The 28% fishmeal was included into the control (Con) diet. The 25%, 50%, 75% and 100% fishmeal were substituted with the combination of graded levels of dry NO biomass residue and casein, referred to as the NO25, NO50, NO75 and NO100 diets respectively. Finally, the salted sea tangle (ST), Laminaria japonica was prepared to compare the effect of the experimental diets on performance of abalone. The essential amino acids, such as isoleucine, leucine, phenylalanine, threonine and valine tended to increase with dietary substitution of fishmeal with NO biomass residue in the experimental diets. Arginine tended to decrease with dietary substitution of fishmeal with NO biomass residue. Survival of abalone fed the experimental diets was higher than that of abalone fed the ST diet for 16 weeks. Weight gain and specific growth rate (SGR) of abalone fed the NO100 diet were higher than those of abalone fed the all other diets. Weight gain and SGR of abalone linearly increased with dietary substation of fishmeal with NO. Shell length of abalone tended to increase with dietary substitution of fishmeal with the combined dry NO biomass residue and casein. The chemical composition of the soft body of abalone was different among treatments except for moisture content. In conclusion, fishmeal in the diets for abalone could be completely replaced with the combined dry NO biomass residue and casein when the 28% fishmeal was included.     

Molecular cloning,expression and functional analysis of a predicted HdiQM gene in small abalone,Haliotis diversicolor

The small abalone (Haliotis diversicolor) is a mollusc and was cultured in south of china. Problems such as the decreasing pathogen‐resistance and their mass mortality during the summer. The increased immunity of small abalone populations is a key factor in resolving these problems. Thus, the study of immunity‐related genes in small abalone has become important. In this study, three bacterial species were initially isolated from small abalone carcasses. The regression of infection was analysed, which revealed that the bacteria species could cause rapid morbidity in small abalone. A QM‐like gene (HdiQM) was found and bacterial challenge tests showed that HdiQM gene expression was induced by the bacterial isolates from small abalone carcasses. Therefore, our results implied that HdiQM was found to be an inflammatory stress‐inducible gene associated with pathogen infection, with important functions in small abalone immunity.     

Substitution effect of sea tangle (ST) (Laminaria japonica) with tunic of sea squirt (SS) (Halocynthia roretzi) in diet on growth and carcass composition of juvenile abalone (Haliotis discus,Reeve 1846)

Substitution effect of sea tangle (ST) with tunic of sea squirt (SS) in diet on growth and carcass composition of juvenile abalone was determined. One thousand four hundred and seventy abalones were distributed into 21 containers. Six formulated diets in triplicate were prepared. A 200 g/kg ST was included into the ST0 diet. The 200, 400, 600, 800 and 1000 g/kg of ST were substituted with the same amount of tunic of SS, referred to as the ST200, ST400, ST600, ST800 and ST1000 diets, respectively. Finally, Undaria was prepared to compare effect of the formulated diets on performance of abalone. The experimental diets were fed to abalone for 16 weeks. Weight gain of abalone fed the ST400 diet was higher than that of abalone fed the ST0, ST600, ST800 and ST1000 diets and Undaria. Weight gain of abalone fed the formulated diets was higher than that of abalone fed the Undaria. The chemical composition of the carcass of abalone was affected by dietary substitution of ST with tunic of SS. In conclusion, ST could be completely substituted with tunic of SS without retardation in performance of abalone. Abalone fed the ST400 diet substituting 400 g/kg ST with tunic of SS achieved the best growth.     

Growth and feeding in juvenile triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814), at two temperatures

Growth and feeding of juvenile triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were investigated at two temperatures of 17 and 21 °C over a 50‐day period. There were no differences in growth between triploid and diploid abalone as measured by shell length and body weight. Both triploid and diploid abalone increased in length but not in weight at 21 °C. Condition indices were similar for triploid abalone maintained at both temperatures; however, those for diploid abalone were significantly higher at 17 °C than at 21 °C. Food intake was significantly greater yet feed conversion efficiency was significantly lower in triploid than in diploid abalone. Both the feeding variables were independent of temperature. On average, diploid abalone were able to convert 1 g of dry food ingested to 0.58 g of body weight, but triploid abalone only 0.44 g.