Effects of temperature and salinity on oxygen consumption of tawny puffer Takifugu flavidus juvenile

The respiratory rates of Tawny puffer Takifugu flavidus juvenile were measured at four temperatures (20, 23, 26 and 29 °C) and seven salinities (5, 10, 15, 20, 25, 30 and 35 g L^?1). The results showed that both temperature and salinity significantly affected the oxygen consumption of tawny puffer juvenile. The oxygen consumption rate (OCR) increased significantly with an increase in the temperature from 20 to 29 °C. Over the entire experimental temperature range (20–29 °C), the Q₁₀ value was 1.59, and the lowest Q₁₀ value was found between 23 and 26 °C. The optimal temperature for the juvenile lies between 23 °C and 26 °C. The OCR at 25 g L^?1 was the highest among all salinity treatments. The OCRs show a parabolic relationship with salinity (5–35 g L^?1). From the quadratic relationship, the highest OCR was predicted to occur at 23.56 g L^?1. The optimal salinity range for the juvenile is from 23 to 25 g L^?1. The results of this study are useful towards facilitating an increase in the production of the species juvenile culture.     

红鳍东方鲀(Takifugu rubripes)生长性状的遗传参数估计

通过人工受精的方法获得红鳍东方鲀8个半同胞家系(16个全同胞家系),共测量了790尾红鳍东方鲀8个半同胞家系(16个全同胞家系)135日龄和200日龄的体质量和体长。将135日龄生长性状作为协变量构建3个动物模型,模型(1)包含加性遗传效应、母本遗传效应和全同胞效应;模型(2)包含加性遗传效应和母本遗传效应;模型(3)包含加性遗传效应和全同胞效应。利用DMU软件,采用平均信息约束极大似然法估计各模型中性状的方差组分,用似然比检验法进行不同模型的差异检验。选择最优模型估计红鳍东方鲀200日龄生长性状的遗传参数。结果表明,母本遗传效应对200日龄红鳍东方鲀生长性状无显著影响,确定模型(3)为最优模型。200日龄红鳍东方鲀,体质量和体长的遗传力分别为0.16和0.14,全同胞效应比率分别为0.12和0.13。研究表明,红鳍东方鲀生长性状具备一定的选择潜力,应用家系选育方法能够获得较好的遗传进展。     

Temperature effects on the development of Enteromyxum spp. (Myxozoa) in experimentally infected tiger puffer, Takifugu rubripes (Temminck & Schlegel)

The effects of water temperature on the development of the enteric myxosporeans, Enteromyxum fugu and Enteromyxum leei, were investigated in experimentally infected tiger puffer, Takifugu rubripes. After naïve tiger puffer were fed gut tissue infected with both E. fugu and E. leei, they were divided into separate tanks and kept at different constant temperature regimes between 10 and 25 °C. Regardless of the water temperature tested, E. fugu was consistently detected with a high prevalence of infection (60–100%), although no sporulation occurred at 10 and 15 °C. Development of E. leei and the onset of disease were suppressed by low water temperatures (<15 °C). However, a temperature increase to 20 °C promoted the development of E. leei, followed by an increase of disease rate in the fish. The present study demonstrates that water temperatures below 15 °C have an inhibitory effect on the development of E. fugu and E. leei, resulting in suppression of enteromyxosis at low temperatures.     

Cytogenetic analysis of hybrids and hybrid triploids between the river puffer,Takifugu obscurus,and the tiger puffer,Takifugu rubripes

Cytogenetic analyses of the river puffer, Takifugu obscurus, the tiger puffer, Takifugu rubripes and hybrids produced between female T. obscurus and male T. rubripes and their hybrid triploids (produced by cold shock treatment at 4°C) were performed. T. obscurus had 2n = 44 chromosomes and 1.84 ± 0.019 pg DNA/cell, T. rubripes had 2n = 44 and 2.64 ± 0.015, the hybrids had 2n = 44 and 2.15 ± 0.010 and the hybrid triploids had 3n = 66 and 3.22 ± 0.010. The erythrocyte values of the hybrids were more similar to those for T. obscurus, whereas the hepatocyte, midgut and proximal tubule kidney cell values of the hybrids fell down between those for the parental species (p < .05). The erythrocyte, proximal tubule, hepatocyte and midgut epithelial cell sizes for the hybrid triploids were 1.5‐fold larger than those for the hybrids (p < .05). The thickness of retina and each layer in the hybrid triploids were 1.1‐fold larger than those of the hybrids (p < .05) and did not differ significantly among T. obscurus, T. rubripes and the hybrids (p > .05); however, the hybrid triploids had fewer cell nucleus outer layers than the hybrids (p < .05). Gonad development in the hybrids and hybrid triploids was less matured than in T. obscurus and T. rubripes. The metaphase nucleolus organizer regions (NORs) and the gill cells of T. obscurus, T. rubripes and the hybrids contained two satellite telocentrics, whereas the hybrid triploids contained three satellite telocentrics.     

Ecological monitoring for ascertaining the bio-safety of liver lipids from some Indian marine puffer fishes

ABSTRACT:   Ecological investigations were carried out on Indian marine puffers, Chelonodon patoca, Sphaeroides oblongus, Lagocephalus lunaris and Lagocephalus inermis , the four major species available in the coastal waters of the Bay of Bengal, India. The seasonal intraspecific and interspecific abundance and average daily landings were noted. The high hepatosomatic index and low lipid ratio of muscle to liver indicated accumulation of lipid in the liver. The lipid content was at its maximum during the monsoon (July–October) in all the species as was observed from the study of the seasonal variation of liver lipids. The puffers are mainly bottom feeders and the molluscs Umbonium vesterium and Donax incarnatus are the major prey group, constituting 56.0–87.5% of their food content. The liver and ovary had the maximum toxicity in monsoon during their spawning season. The liver oils so far tested from these fishes had no toxicity and the study reveals that the ecologic information will be helpful in monitoring the quality for the safe isolation of polyunsaturated fatty acid – enriched oil from these non-conventional sources.     

Induced ovulation using LHRHa in anadromous obscure puffer Takifugu obscurus cultured entirely in freshwater

Puffer fishes of the order Tetradontidae exist in both anadromous and non-anadromous seawater resident forms. The obscure puffer akifugu obscurus is an anadromous species whose intensive culture in freshwater has developed rapidly in China. To mass produce larvae for intensive culture, induction of ovulation of 3-year-old obscure puffer cultured entirely in freshwater was attempted by giving the fish multiple injections of LHRHa. Twenty 3-yearold cultured obscure puffers were treated with multiple injections of LHRHa at a constant dosage of 30 g of LHRHa kg-1 of body weight with 36 h interval between injections. Beginning two days after hormonal treatment, abdominal palpation was performed every day to check expansion and hardening of the abdomen of the fish due to hydration of oocytes that indicates the completion of final oocyte maturation. The first four fish ovulated after the second LHRHa injection on day 3, but most females ovulated after the fourth hormone injection. A total of 18 fish (90%) ovulated over a period of 7 days, while no fish ovulated in the control group. The mean fertilization rate and the mean hatch rate was 67.1% and 87.6%, respectively. The viability of newly hatched larvae was very good, with a high survival rate of 98.6% 24 h post-hatch. These results indicate that cultured obscure puffer, which are not allowed to undergo diadromous migration and are entirely cultured in freshwater, could be induced to complete maturation and ovulate by simple multiple injections of LHRHa and that the eggs could be successfully hatched into viable larvae.     

关于红鳍东方鲀Fugu rubripes(Temminck et Schlegel)苗种的长途运输的探讨

红鳍东方鲀苗种运输的好坏,直接关系到河鲀养殖的成败。本文从鲀苗运输前的准备,到采用尼龙薄膜袋、大容量桶充氧运输和活水船运输等方法,介绍鲀苗的长途运输技术,以提高鲀苗的运输成活率。     

暗纹东方鲀致病性维氏气单胞菌的分离鉴定

从濒死的暗纹东方鲀(Takifugu obscurus)体内分离到一株优势菌株,经形态观察、生化、16 S rDNA聚合酶链式反应(PCR)以及人工感染健康暗纹东方鲀和ICR小鼠等试验可知,该菌对小鼠和暗纹东方鲀半数致死量(LD卯)分别为2.26×106 CFU/mL、5.96×104 CFU/mL;其16 S rDNA序列与维氏气单胞菌具有高度的同源性,根据该菌的形态特征、生理生化特性,初步鉴定该菌为维氏气单胞菌(Aeromonas veronii),命名为NT-HV.选择9种水产常用药物进行药敏试验,结果显示该菌对氟苯尼考、复方新诺明、新霉素、氧哌嗪青霉素敏感,对养殖场常用的四环素、强力霉素、羧苄青霉素、氨苄青霉素不敏感,提示在药物的使用过程中应注意药物的浓度和合理轮换.     

Effects of temperature on fertilized eggs and larvae of tawny puffer Takifugu flavidus

Tawny puffer Takifugu flavidus is a species found in China considered to have potential for aquaculture. Experiments were conducted to determine the optimal temperature for its incubation and larval culture. Fertilized eggs collected from cultured broodstocks that were induced to ovulate with a [d ‐Ala⁶‐Pro⁹‐Net]‐luteinizing hormone‐releasing hormone analogue were inseminated. The effect of temperature (19, 20, 23, 26 and 29 °C) on the hatch rate, incubation period, viability of 24 h post‐hatch larvae and total mortality rate was assessed. The effect of temperature (20, 23, 26 and 29 °C) on the growth and survival of larvae from 3 to 19 days after hatching (dah) was also assessed. The results showed that the optimal temperature for successful development of fertilized eggs ranged from 23 to 26 °C, and the highest hatch rate, the optimal viability of 24 h post‐hatch larvae and the lowest total mortality rate were all predicted using quadratic equations. The relationship between temperature and the incubation period of tawny puffer eggs was determined using the effective degree‐day model. The temperature at developmental zero (t₀) was 11.34 °C, and the sum of effective degree‐days (k) was 52.356. The survival rate of tawny puffer larvae at 20 °C was significantly lower than among 23, 26 and 29 °C, whereas the survival rate was not significantly different from that at 23, 26 and 29 °C. The larval growth rate increased rapidly as the temperature increased, showing a linear relationship in the range of temperatures investigated. The optimal temperature for larval culture ranged from 23 to 29 °C.     

小鼠生物法和酶联免疫法(ELISA)定量监测沿海5省养殖河豚鱼中的河豚毒素(TTX)

为进一步扩大国内养殖河豚鱼消费市场提供依据,应用小鼠生物法监测了我国辽宁、河北、山东,江苏和福建4种养殖河豚鱼(红鳍东方鲀,菊黄东方鲀,双斑东方鲀和暗纹东方鲀4种组织(皮、肉、肝脏和性腺)中河豚毒素(TTX)含量及周年变化,并用酶联免疫法(ELISA)同步检测了山东红鳍东方鲀的皮,肉和肝脏各组及个别卵巢样品。结果4种养殖河豚鱼的皮,肉和肝脏每组平均含毒量均属无毒(小鼠生物法检测结果小于0.5μg/g,ELISA检测结果小于0.8μg/g)。卵巢发现一强毒例,精巢则全部无毒。通过监测,发现养殖河豚鱼组织器官的毒力呈现一定的周年变化。ELISA法与小鼠生物试验测得的结果相符合。养殖河豚鱼皮,肉和精巢认为可以考虑科学安全的利用,肝脏须谨慎对待,由于养殖河豚鱼上市规格较小,卵巢一般无食用意义,加工过程应注意不要污染可食部分。