一株水产用益生枯草芽孢杆菌液体发酵初步研究

通过正交实验、单因素实验和100L发酵罐中试确定了枯草芽孢杆菌HJ02工业生产用的优化液体培养基和发酵工艺条件。最佳培养基配方为:葡萄糖10g/L、玉米粉8g/L、豆粕粉25g/L、硫酸锰30.8mg/L、硫酸镁5g/L、磷酸二氢钠0.52g/L、磷酸氢二钠2.33g/L;最优发酵工艺条件:培养温度30℃,初始pH值7.0,最佳接种的菌龄是18h。     

一株水产用益生枯草芽孢杆菌液体发酵初步研究

为解决工业化生产中枯草芽孢杆菌(Bacillus subtilis)活菌数量低、成本高的问题,通过正交试验、单因素试验和100 L发酵罐中试,确定了枯草芽孢杆菌(Bacillus subtilis)HJ02工业生产用的优化液体培养基和发酵工艺条件。最佳培养基配方为:葡萄糖10 g/L、玉米粉8 g/L、豆粕粉25 g/L、硫酸锰30.8 mg/L、硫酸镁5 g/L、磷酸二氢钠0.52 g/L、磷酸氢二钠2.33 g/L;最优发酵工艺条件为:培养温度30℃,初始pH 7.0;最佳接种菌龄是18 h。优化后培养基成本降低了50%以上,细菌浓度达到了7.19×109个/mL。     

枯草芽孢杆菌固态发酵工艺研究

对枯草芽孢杆菌（Bacillus Subtilis）的固态发酵工艺进行了研究，包括碳源、氮源、含水量、初始pH、接种时间、接种量等影响因素，并通过单因子试验和正交试验优化，确定了枯草芽孢杆菌的固态发酵工艺为：（1）培养基：麸皮19．5g，稻谷壳0．5g，豆粕1．0g，水22mL；（2）发酵条件：初始pH为7．0、接种时间20h，接种量为0．9mL。照此工艺发酵，枯草芽孢杆菌的活茵数高达435亿个／g。     

产虾青素海洋酵母菌YS-185的鉴定及发酵条件优化

以26S rDNA法将实验室保藏的1株产虾青素的海洋酵母菌YS-185鉴定为粘红酵母。以海洋酵母菌YS-185为试验菌株,运用摇瓶发酵优化的方式,探索培养基组分和发酵工艺条件对该菌发酵的影响。实验结果表明,该菌生长最适培养基组分为葡萄糖8 g/L、蛋白胨8 g/L,最适生长起始pH值为5.5、转速220 r/min、接种量8%、温度20℃;虾青素合成的最佳培养基组分葡萄糖8 g/L、蛋白胨8 g/L,最佳虾青素合成条件:pH 5.5,转速220 r/min,接种量8%,培养温度25℃。发酵优化后的虾青素产量2.670μg/ml,较优化前的1.572μg/ml提高了69.8%。温度对酵母菌的生长和虾青素的合成都有显著影响。海洋酵母菌YS-185优化后的发酵条件有规模化生产虾青素的应用潜力。     

枯草芽孢杆菌培养基配方优化的研究

枯草芽孢杆菌培养基的组分是由葡萄糖、蛋白胨、酵母膏、磷酸二氢钾、碳酸钙等5种原料构成，采用L1（4^5）正交表，将5种原料作为枯草芽孢杆菌培养有影响的因素，通过试验数理统计的直观和理论分析，对其配方进行优化：试验结果表明，当培养基的配方为无水葡萄糖3．50g／L、蛋白胨0．83g／L、酵母膏0．50g／L、磷酸二氢钾0．35g／L和碳酸钙0．25g／L，温度（34±2）℃时，培养16h即可达到生长峰值。由于枯草芽孢杆菌光学密度（optical density，OD）与活菌数量的关系：Y=0．5182x^2＋1．4462x＋1．9714（r=0．996343），接种的枯草芽孢杆菌由1．9714×10^8cfu／mL提高到3．3124×10^8cfu／mL。优化的枯草芽孢杆菌培养基条件能有效促进枯草芽孢杆菌生长。     

渔源解淀粉芽孢杆菌CQN-2菌株培养基及发酵条件优化

CQN-2是一株具有抗病、促生长等多种功能的肠道内源性解淀粉芽孢杆菌。为研究其最佳培养条件,从而为规模化生产发酵提供依据,本文以菌体生物量为指标,采用单因素试验和正交试验对CQN-2菌株的最适培养基及发酵条件进行优化。结果表明,CQN-2菌株的最适碳源为可溶性淀粉,最适氮源为细菌学蛋白胨,经优化后的最佳培养基配方为可溶性淀粉20 g/L、细菌学蛋白胨30 g/L、糖蜜50 g/L、KH_2PO_4 0.5 g/L、MgSO_4 0.5 g/L、NaCl 0.3 g/L、Mn~(2+) 5 mmol/L、Al~(3+) 1 mmol/L;最佳发酵培养条件为初始pH值7.0,接种量为3%、装液接种量25 mL/250 mL;使用优化后的培养基将CQN-2接种于5 L发酵罐进行高密度发酵培养36 h后的活菌数为3.03×10~(12) CFU/mL。     

一株刺参益生菌的发酵配方及其发酵条件优化

以健康刺参肠道的益生茵——枯草芽孢杆菌(Bacillus subtilis)为研究对象,以豆粕、葡萄糖和氯化钠为基础发酵培养基,通过单因素和正交试验,确定该菌株适用于工业生产的最佳发酵培养基配方;通过单因素试验,确定最佳发酵条件;同时在生物反应器中进行扩大培养试验,得到其最佳种龄和发酵时间.试验确立该茵株的最佳培养基配方为:氯化钠10g/L,葡萄糖2.5g/L,豆粕20g/L;最佳发酵条件为:培养温度28℃,初始pH 7.5,转速170r/min,菌种接种量5％.以最佳发酵条件和培养基,在10L生物反应器中进行扩大培养试验,得到最佳种龄为24h、最佳发酵时间为32h,菌体细胞浓度最高达到8.5×109cfu/mL,芽孢生成率达到91％.研究结果为刺参微生态制剂的工业化生产提供基础数据,为海水养殖专用微生态制剂的开发提供参考.     

不同营养盐浓度对雨生红球藻生长的影响

以MAV为基本培养基，用单因子和正交实验的方法研究雨生红球藻(Haematococcus pluvialis)生长所需的基本元素——氮、磷、铁对其生长的影响。结果表明：用单因子实验得出雨生红球藻生长所需适宜的氮、磷、铁浓度分别为0．1g／L，0．02—0．04g／L，0．3—0．6mg／L；而多因子正交试验结果得出该藻生长的最优水平是A2B2C2，即N 0．3g／L，P 0．02g／L，Fe 0．5mg／L。     

氯氰菊酯对三疣梭子蟹幼体的急性毒性研究

在实验室条件下，研究了氯氰菊酯对三疣梭子蟹幼体急性毒性试验，结果表明氯氰菊酯对三疣梭子蟹I、Ⅱ、Ⅲ、Ⅳ期蚤状和大眼幼体的24dx时半致死浓度和安全浓度分别是I0．0178μg/L、0．0024μg／L；Ⅱ0．022μg／L、0．0041μg/L；Ⅲ0．026μg/L、0．005μg／L；1V0．06μg/L、0．018μg/L；大眼幼体0．065μg/L、0．0031μg/L。     

一株海洋中性蛋白酶高产菌S-3685的鉴定及产酶条件

通过生理生化、分子生物学、单因子优化等方法研究了来自南海海域一株产中性蛋白酶菌株S-3685,并对其在250 ml摇瓶中的培养条件进行了优化。结果显示,该菌株初步确定为芽孢杆菌属(Bacillus),发酵培养的最佳碳、氮源分别为葡萄糖10 g/L和豆面10 g/L,牛肉膏5 g/L,酵母膏5 g/L。无机盐MgSO4·7H2O、Na2CO3、KH2PO4最佳浓度分别为0.2 g/L、2.0 g/L、1.0 g/L;菌株在培养基起始pH=7.0、4%接种量、15 ml/250 ml (v/v)装液量和30℃的条件下,发酵72 h获得较高的酶产量。在最佳培养条件下产酶量为4250 U/ml,是优化前的5倍。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

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.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.