柱前衍生-高效液相色谱法测定浒苔多糖的组成

研究了浒苔多糖样品经三氟乙酸完全水解而无损失的最适条件,并且在优化流动相洗脱程序等色谱条件的基础上,建立了1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生-高效液相色谱法分析浒苔多糖的单糖组成及含量的方法。该方法采用配备紫外检测器的高效液相色谱仪,在250 nm波长下进行测定,外标法定量。结果表明,在此条件下,8种单糖能够良好分离,各单糖在1-100μg/ml范围内具有良好的线性关系,相关系数r≥0.999,回收率在76.0%-108%之间,相对标准偏差RSD10%。采用该方法对浒苔多糖样品进行组成及含量分析,发现无论样品原料为何种浒苔,浒苔多糖均以鼠李糖为主,同时还含有葡萄糖醛酸、葡萄糖、木糖、半乳糖以及少量的甘露糖、半乳糖醛酸和岩藻糖。     

离子色谱法同时测定水中7种阴离子的含量

为建立快速准确地同时测定水中F-、Cl-、NO2-、SO24-、PO34-、Br-、NO3-等7种阴离子含量的离子色谱分析方法,通过配制不同浓度的多种淋洗液,选择合适的淋洗液、淋洗液流速和离子色谱仪参数,使用ICS-3000离子色谱仪系统、Dionex IonPac AS-23阴离子分离柱和IonPac AG-23保护柱进行了检测试验,分析这种方法的线性、检测限、回收率和精密度。结果表明,用0.45μm微孔滤膜过滤水样,以4.5mmol.L-1Na2CO3+0.8 mmol.L-1NaHCO3为淋洗液,淋洗液的流速为1.0 mL.min-1,混合标准溶液的进样量为50μL,进行电导抑制检测,可以有效分离这些阴离子,标准曲线在一定范围内具有良好线性,线性相关系数(R2)为0.999 3～0.999 7,相对标准偏差(RSD)0.2%～0.6%,各离子的回收率为90%～110%,检测限为0.011～0.052 mg.L-1。     

海参皂苷的提取条件研究

海参皂苷极性较大,多采用醇提法进行提取,为减少海参皂苷制备过程中多糖和蛋白质的干扰,简化后续分离过程,本实验考察了乙醇浓度、温度、料液比对干海参中海参皂苷提取的影响。结果表明:乙醇浓度为0%、80%时海参皂苷得率较高,其中0%乙醇提取时提取液中多糖含量较少,更有利于后续分离;20℃、30℃提取时皂苷得率高,30℃提取时杂质更少;料液比为1∶15时提取得到的海参皂苷含量较高,提取时间控制在8 h内,可有效减少杂质产生且能获得较多皂苷。     

水溶性牡蛎多糖的降血压活性

牡蛎中含有丰富的多糖。从牡蛎中制备的水溶性多糖经HPLC测定,其单糖组成为葡萄糖,以葡聚糖分子筛测定其分子量为(3.93~10.84)×106 Da。以牡蛎多糖(7g/kg)对高血压模型大鼠灌胃均具有较明显的降低收缩压和舒张压作用。     

海参水煮液酶解多肽的抗氧化活性

以海参水煮液的冻干粉为原料,选取中性蛋白酶、胃蛋白酶和胰蛋白酶分别酶解制备多肽,测定其对·OH、O2-·和DPPH·自由基的清除能力,并与合成抗氧化剂TBHQ对比.结果表明,3种蛋白酶酶解制得的海参水煮液多肽对·OH、O2-·和DPPH·自由基的清除能力均随样品质量浓度的升高而增强;其中,中性蛋白酶酶解制得的海参水煮液多肽清除·OH、O2-·和DPPH·自由基的IC50值依次为8.565、6.658和2.015mg/ml,其对O2·的清除能力优于TBHQ.经液相色谱法测定,中性蛋白酶、胃蛋白酶和胰蛋白酶酶解制得的海参水煮液多肽分子量分别分布在＜2 500、＜3 500和＜1 000 D的小分子肽中.     

鸭绿沙塘鳢精子生理学特征

为探究鸭绿沙塘鳢(Odontobutis yaluensis)精子生理学特征, 提高精子活力, 测定了其精液浓度、精子密度、 pH 和精子活力, 以精子激活率(activation rate, AR)、快速运动时间(fast movement time, FT)以及精子寿命(life time, LT)作为评价精子活力的指标, 检测了水温、pH、离子(NaCl、KCl、CaCl₂、MgCl₂)、非离子(葡萄糖、Tris、甘油)、 碱度(NaHCO₃)共 10 种单因子条件下的精子活力, 并在此基础上进行 17 组复合因子精子激活液的筛选。结果表明, 鸭绿沙塘鳢精巢前段精子活力、精子密度、精液浓度均高于中后段, 精巢整体精子密度(1.83±0.03)×10⁹ 个/mL, 精液浓度 23.10%, pH 6.9±0.1。单因子精子激活液中, 鸭绿沙塘鳢在水温 20 ℃、pH 6.0、NaCl 68 mmo/L、 KCl 54 mmol/L、CaCl₂ 27 mmol/L、葡萄糖 28 mmol/L、甘油 65 mmol/L 条件下精子 AR, FT 和 LT 均最高, 在 MgCl₂ 11 mmol/L、Tris 4 mmol/L 激活液中精子激活率最高。复合因子精子激活液中, 精子在 KCl 40 mmol/L、甘油 33 mmol/L、Tris 4 mmol/L 条件下 AR, FT 和 LT 均最高, 精子活力最高。综上所述, 在进行鸭绿沙塘鳢人工授精时, 可直接使用精巢前段(生精部), 同时应用复合因子精子激活液(KCl 40 mmol/L、甘油 33 mmol/L、Tris 4 mmol/L)提高精子活力。     

麒麟菜多糖的研究——Ⅰ.琼枝多糖的性质及其红外光谱

琼枝多糖是琼枝(Eucheuma gclatinae)分离得到的一种硫酸酯化半乳聚糖。构成这种多糖的单糖主要是 D-半乳糖和3,6-脱水-D-半乳糖。分子量为 1.99×10~5,比旋光度为正值。大多数碱金属阳离子和碱土金属阳离子能使此多糖的胶凝能力提高。用碱或石灰处理时,琼枝多糖便部分脱去硫酸酿基团,3,6-脱水-D-半乳糖的含量增加。红外光谱分析证明,琼枝多糖在1240cm~(-1) 、930cm~(-1)和845cm~(-1)有吸收峰。用氯化钾分级时,琼枝多糖可分为溶于氯化钾溶液和不溶于氯化钾溶液两个级分;前者的红外光谱除了同后者一样在 1240cm~(-1),930cm~(-1)和845cm~(-1)有吸收峰外,在 820cm~(-1)处还有吸收峰。根据琼枝多糖的组成,性质和红外光谱,可以推断,溶于氯化钾溶液的级分是类 mu-卡拉胶;不溶于氯化钾溶液的级分是类 kappa—卡拉胶。     

海带岩藻聚糖硫酸酯电渗析分离工艺

采用电渗析法对盐沉后的海带酶解液中岩藻聚糖硫酸酯进行分离,探索工业化分离生产岩藻聚糖硫酸酯的方法,以解决目前乙醇沉淀法存在的安全性和高成本等问题。以脱盐率、糖保留率为检测指标,采用响应面法优化了电渗析工艺参数。结果显示,在操作电压80 V、料液流量3.2 L/min、固形物浓度10 mg/ml、p H=5的条件下,电渗析连续循环3次,海带酶液解干基中多糖含量由40.17%提高至47.11%,硫酸根含量由3.36%提高至4.97%。电渗析后海带酶解液干基中的金属离子含量为Ca 0.13 mg/g、Mg 16.04μg/g、Cu 0.29μg/g、Se 11.7μg/g、Cr 8.06μg/g,Pb未检出,较电渗析前均有降低。电渗析对脱除褐藻胶的海带酶解液进行脱盐纯化处理,可有效地分离纯化出岩藻聚糖硫酸酯。     

拟穴青蟹卵巢蛋白质双向电泳的样品制备方法

为探索适用于拟穴青蟹卵巢蛋白质双向电泳的样品制备方法,比较了TCA/丙酮沉淀法和3种裂解液抽提法对总蛋白的提取效果,4种方法分别得到133、369、306和417个蛋白点。采用裂解液Ⅲ(7 mol/L尿素、2 mol/L硫脲、4% CHAPS、40 mmol/L Tris-base、65 mmol/L DTT、2% IPG Buffer、Protease in hibitor cocktail、1 mmol/L EDTA)提取蛋白所得图谱效果最好,背景清晰,蛋白点最多。     

不同盐度激活液、K+浓度及保存时间对日本鳗鲡精子活力的影响

在6种不同盐度(34、32、30、28、26和22)激活液、3种不同K+浓度(25 mmol/L、30 mmol/L和35 mmol/L)稀释液和不同保存时间(0 h、24 h、48 h、72 h和96 h)条件下,对日本鳗鲡(Anguilla japonica)精子的活力进行观察和测定.结果表明,激活液盐度为30时精...     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O₂ (by means of a Venturi vacuum tube), and the subsequent denitrification becomes more efficient due to elimination of the problems of oxygen inhibition of denitrification and aerobic consumption of cotton wool. The cotton wool medium also serves as a physical barrier that traps organic particles, which, in turn, act as an additional carbon source for denitrification. Operation in the proposed system gives an extremely low C/N ratio of 0.82 g of cotton wool/g of nitrate N, which contributes to a significant reduction of biofilter volume. The additional advantage of using solid cotton wool as the carbon source is that it does not release organic residuals into the liquid to be recycled. Operation of the system over a long period consistently produced effluents with low nitrate levels (below 10 mg N/l), and there was only a very small need to replace system water. The overall treatment scheme, also incorporating an aerobic nitrification biofilter and a granular filtration device, produced water of excellent quality, i.e., with near-zero levels of nitrite and ammonia, a sufficiently high pH for aquaculture, and low turbidity. The proposed system thus provides a solution for sustainable small-scale, urban aquaculture operation with a very high recovery of water (over 99%) and minimal waste disposal.     

Fertilization by refrigerator stored sperm of the Indian major carp, Labeo calbasu (Hamilton, 1822)

This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g^?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 10⁹ (cells mL^?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg^?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.     

Effects of metomidate anaesthesia or transfer to pur sea water on plasma parameters in ammonia-exposed Atlantic salmon (Salmo salar L) in sea water

Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14–15 mg l^–1 TA-N (total ammonia-N) in sea water in 1 m³ tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2–20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in ammonia-free sea water; or C) 2–20 min after the fish were transferred to 15 l of ammonia-free sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p 0.05), but plasma urea, osmolality, Na^{+, Cl–, Ca2+ or Mg2+} levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p 0.02).