温度对真鲷蛋白酶和淀粉酶活力的影响

研究了不同温度条件下真鲷胃、肠、肝胰脏和幽门盲囊4个部位蛋白酶和淀粉酶活力的变化。结果表明：在5．50±0．5℃范围内（每隔5℃为1个梯度）,胃蛋白酶的最适温度为25℃,胃淀粉酶的最适温度是30℃;肠蛋白酶的最适温度是35℃,肠淀粉酶的最适温度是20℃;肝胰脏蛋白酶的最适温度是40℃,肝胰脏淀粉酶的最适温度是30℃;幽门盲囊蛋白酶的最适温度是30℃,幽门盲囊淀粉酶的最适温度在40℃。     

真鲷育苗中的病害及防治

介绍了在真鲷育苗中，亲鱼和鱼苗常发生的病害及防治方法。其中，亲鱼由霉菌引起的竖鳞病及仔鱼的隐核虫病，鱼虱病，在此之前未见报道。     

Seasonal changes in sperm production and quality in the red porgy Pagrus pagrus (L.)

Cultured red porgy Pagrus pagrus (L.) males (n=6) were sampled every 2 weeks for milt, in order to monitor changes in sperm quality parameters during a whole spawning period. On 11 January 2001, 60% of the fish were spermiating, increasing to 100% in mid‐February and dropping to 30% by mid‐April. Sperm density showed a slight increasing trend, with mean values ranging between 8.6 and 23.7×10⁹ spermatozoa mL^?1. Sperm motility percentage exhibited a significant improvement during the spawning season (analysis of variance (anova ) P=0.0001). The duration of forward motility for the major part of the monitoring period ranged between 2 and 4 min. Red porgy spermatozoa maintained their viability for many days after whole storage of milt at 4°C. During the monitoring period there were significant changes in the mean duration of sperm survival after cold storage, ranging from 5 to 12 days. The total volume of expressible milt was maximal on 28 March, increasing from a mean value of 1.7 mL to 5.3 mL kg^?1. Milt production of captive‐reared red porgy does not appear to be limiting, when compared with the volume of expressible milt produced by other cultured marine fishes.     

月桂酸酯对真鲷幼鱼脂质蓄积和生理活力的影响

在配合饲料中加人月桂酸酯（0．5％）饲喂真鲷稚鱼（0．3g）以评价其对脂质蓄积及生理活力的影响。经过47d饲养，对真鲷的生长情况、鱼体性状和体成份进行测定和分析，并通过施以麻醉和离水应激以评价其抗逆能力。结果表明，饲料中添加月桂酸酯未影响生长，但提高了肌肉比率，降低了比肝重和腹腔脂肪组织比率。同时脂肪细胞缩小，肝脂及肝脂中中性脂肪比率下降，组织中DHA比率有上升趋势。另外，饲料月桂酸酯增强了真鲷肝功能和离水等抗逆能力，指出月桂酸酯的效果可能与组织中DHA比率上升有关。     

Does water temperature determine year class strength in New Zealand snapper (Pagrus auratus,Sparidae)?

The abundance of 1+ snapper (Pagrus auratus) was estimated by trawl surveys and was found to vary 17-fold over 7 years. There was a strong positive correlation between year class strength and autumn (April-June) sea surface temperature during the 0+ year, with the latter explaining 94% of the variability in year class strength. The underlying mechanism is unknown, but three hypotheses relating snapper growth and survival to temperature are discussed. The strengths of the 1991 and 1992 year classes are predicted to be below average and extremely weak, respectively.     

Low allozyme variation in snapper, Pagrus auratus, in Victoria, Australia

The population genetic structure of snapper, Pagrus auratus (Bloch and Schneider), in Victoria was investigated using six polymorphic allozyme loci. Fish were sampled from four sites in Victoria and single locations in South Australia, Western Australia and New Zealand. Although there were distinct genetic differences between the snapper populations from each of the Australian states and New Zealand, only minor and largely insignificant differences were detected among Victorian populations. The results are consistent with previous genetic and tagging studies that indicate no mixing between snapper stocks in Victoria and Spencer Gulf in South Australia. This justifies separate management of the snapper fisheries in these regions. The low levels of polymorphism and heterozygosity in Victorian snapper suggest an isolation by distance model of population structure rather than one of discrete subpopulations.     

真鲷天然抗性相关巨噬蛋白全长cDNA的克隆与序列分析

Natural resistance associated macrophage protein (Nmmp) is an innate resistance protein to intracellular parasites, which is expressed plentifully in macrophage ceils. Nramp has been studied in mouse, human, cattle, rainbow trout and channel catfish.However, tittle was known about the structure of Pagrus major Nramp. In order to get the complete sequence of Pagrus major Nramp, a pair of primer is designed according to a 200bp known sequence of Pagrus major Nramp cDNA. By the use of SMART RACE, the full Nramp of Pagrus major cDNA about 5 000 bp was obtained, including about 200 bp 5‘ terminal region (UTR),complete encoding region and 3‘ terminal region. There were 3 ployA signals, which showed many possibilities of cutting at 3‘ terminal region. The character of Pagrus major Nramp nucleotide sequence and deduced amino acid sequence are analyzed. 12 putative transmembrane(TM) regions, a consensus transport motif (CTM), a predicted protein kinase C phosphroylation site and three predicted N-link glycosylation sites are indicated in its deduced amino acid sequence. The ‘consense transport motif‘ CTM is located etween TM8 and TM9. Furthermore, a protein kinase C phosphroylation site and three N-link glycosylation sites were predicted. The lignment of amino acid sequences between Pagrus major Nramp cDNA and several animals is analyzed and the deduced amino acid equence of Pagrus major Nrarnp had 77.8%, 83.0%, 82.3%, 80.0%, 81.1%, 60.4%, 70.3%, 58.5%, 69.5% identity ith rainbow trout α(AAD20721), rainbow trout β(AAD20722), channel catfish(AF400108), fathead minnow (AAF01778),common carp (CABal96), mouse 1 ( AAA39838 ), mouse 2 ( AAC42051 ), human 1 ( D50403 ), human 2 ( NP - 0(106(18 ),respectively. The alignment reveals high conservation in TM and CTM regions. Analysis result makes us get familiar with the structure nd character of fish Nramp, furthermore, offers some infonnat/on for the enhancement of immunity of fish and genetic amelioration on fish breeding.     

Digestive enzyme activity of the red porgy (Pagrus pagrus, L.) during larval development under culture conditions

The ontogenic development of the main digestive enzymes (proteases, amylase and lipase) in the red porgy, Pagrus pagrus, larvae was assayed during the larval development. The green water technique was carried out for larval rearing and whole‐body homogenates were used for enzymatic assays in triplicate. Significant alterations in specific activities of all digestive enzymes measured during the period of this study were mostly related to metamorphosis and weaning. Trypsin‐ and chymotrypsin‐specific activities were first detected on day 3, together with opening of the mouth, and slightly increased until 25 days after hatching (DAH). After this period, the specific activities of these enzymes slightly decreased. Pepsin was first detected on day 28, concurrent with stomach formation, and a sharp increase was observed until 30 DAH. A slight decrease was measured from this date until the end of the experiment. Both amylase and lipase were measured for the first time on days 2 and 4 respectively, and the specific activities of these enzymes showed similar patterns during the first week of the study. Then, slight variations were observed until 30 DAH and while lipase‐specific activity declined, an increase in the specific activity of amylase was found until the end of the experiment. It is concluded that the variations observed in the specific activity of digestive enzymes were related to either metamorphosis, such as the formation of the stomach (28 DAH), or to changes in food composition. The profile of the developmental pattern of the main digestive enzymes detected in P. pagrus is similar to that described for other Sparid species.     

Optimum dietary taurine level in casein-based diet for juvenile red sea bream Pagrus major

ABSTRACT:   This study was conducted to investigate the effect of dietary taurine and cholyltaurine (C-tau) on growth and body composition of juvenile red sea bream Pagrus major . Semi-purified casein-based diets supplemented with 0 (control diet), 0.1, 0.3, 0.5 and 0.7% taurine and 0.5% C-tau were fed to red sea bream (average body weight 4.7 g) for 6 weeks at 20°C. The growth and feed efficiency were the lowest in fish fed the control diet. Taurine supplementation improved the growth and feed efficiency of fish dose-dependently, and the taurine requirement was estimated as 0.52% in terms of optimizing growth and 0.48% in terms of optimizing feed efficiency. Taurine content in the whole body and liver increased with the dietary taurine level. Supplemental C-tau at the 0.5% level had limited effects on the growth and no effect on body taurine, biliary bile salt and liver fat contents. From these results it can be inferred that the optimal dietary taurine requirement of juvenile red sea bream is 0.5% on a dry weight basis, and that the supplementation of taurine in the diet not only improves the growth but also increases hepatic lipid levels of red sea bream juveniles.     

Fatty acids in muscle of wild and farmed red porgy, Pagrus pagrus

The total fat content and the fatty acids of total lipids (TL), phospholipids (PL) and triacylglycerols (TAG) were analysed in white muscle from wild and reared red porgy, Pagrus pagrus (L.). The fat percentage was higher in reared (3.03 ± 0.57%) (mean ± SE) than wild (0.65 ± 0.03%) fish. The fatty acid pattern of reared porgy TL reflected the diet's lipid. Wild red porgy showed higher levels of ω3 and ω6 polyunsaturated fatty acids (PUFA) than reared, but both the atherogenic index and the index of thrombogenicity were very low for both wild and reared red porgy. The lipid fractions showed that the PL were composed of very high levels of PUFA, especially 22:6ω3, and their composition seemed to be better regulated than the composition of TAG. TAG showed greater differences between wild and reared fish, presumably because they reflected the dietary content of lipids. PUFA were the principal component of wild red porgy TAG.     

Effects of dietary astaxanthin source and light manipulation on the skin colour of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)

Two experiments were conducted with Australian snapper Pagrus auratus (Bloch and Schneider, 1801). The first was aimed at determining the dietary level of astaxanthin that improved skin redness (CIE a^*values) of farm‐reared snapper. Farmed snapper (ca. 600 g) fed a commercial diet without carotenoids were moved to indoor tanks and fed the same diet supplemented with 0, 36 or 72 mg astaxanthin kg^?1 (unesterified form as Carophyll Pink?) for nine weeks. Skin redness (CIE a^* values) continued to decrease over time in fish fed the diet without astaxanthin. Snapper fed the diet containing 72 mg astaxanthin kg^?1 were significantly more red than fish fed the diet with 36 mg astaxanthin kg^?1 three weeks after feeding, but skin redness was similar in both groups of fish after 6 and 9 weeks. The second experiment was designed to investigate the interactive effects of dietary astaxanthin source (unesterified form as Carophyll Pink? or esterified form as NatuRose?; 60 mg astaxanthin kg^?1) and degree of shading (0%, 50% and 95% shading from incident radiation) on skin colour (CIE L^*a^*b^*) and skin and fillet astaxanthin content of farmed snapper (ca. 800 g) held in 1 m³ floating cages. After 116 days, there were no significant interactions between dietary treatment and degree of shading for L^*, a^* or b^* skin colour values or the concentration of astaxanthin in the skin. Negligible amounts of astaxanthin were recovered from fillet samples. The addition of shade covers significantly increased skin lightness (L^*), possibly by reducing the effect of melanism in the skin, but there was no difference between the lightness of fish held under either 50% or 95% shade cover (P>0.05).     

Hypoxic conditions induce centrum defects in red sea bream Pagrus major (Temminck and Schlegel)

A previous study elucidated that an extreme hypoxia during somitogenesis induced the most frequent skeletal malformation centrum defects in red sea bream (RSB), Pagrus major. In this study, details of the hypoxic conditions to induce them in RSB, dissolved oxygen (DO) concentration and exposure time to hypoxia, were investigated. Fertilized eggs were exposed to seawater of six DO concentrations (0%, 10%, 25%, 50%, 75% and 100% of saturation) for seven different periods (5, 10, 30, 60, 120, 240 and 360 min) during somitogenesis. Somitic disturbances in newly hatched larvae were induced by exposure to 0% and 10% DO concentration for 10 and 120 min and longer respectively. Rearing eggs exposed to hypoxic condition of 10% DO for 240 min for 40 days post‐hatch showed that the location and the frequency of somitic disturbances in larvae and centrum defects in juveniles were significantly correlated (P<0.01). Dissolved oxygen concentration of the interstitial water in the egg high density layer formed at the water surface in a stationary state abruptly decreased to 3.7% within 7 min. Centrum defect induction by exposure of eggs to extreme low DO concentrations for a short period, which is the probable situation in the practical juvenile production, suggests that careful maintenance of DO concentration is important in the incubating water of fertilized eggs during egg sorting and transportation, where eggs are made into a pile and undergo hypoxia, for the prevention of centrum defects.     

利用AFLP指纹技术研究中国沿海真鲷群体的遗传变异和趋异

用AFLP指纹技术在中国沿海真鲷群体进行遗传学变异和趋异分析，使用了6对引物：E－ACC／M－CAT、E－AGG／M－CTG、E－AGG／M－CTT、E－AAC／M－CTA、E－ACA／M－CTG、E－AAC／M－CAA，在威海、厦门和北部海湾海区三个野生群体区42个体中检出646个扩增位点（片段大小50－400bp)，其中70％位点在群体内或群体间呈现多态。三个群体的多态位点比例变化在58．4％－64．0％，遗传相似系数变化在0．8425－08200，以威海群体的遗传变异量最大，北部湾群体的最小。三群体空遗传距离和UPGMA谱系图显示，厦门海区与北部湾的真鲷差异较小，可以认为是同一个亚种群的不同群体，黄海真鲷与前二个群体差异比较大，属于另一个不同的亚种群。     

Genetic diversity of red sea bream Pagrus major in western Japan in relation to stock enhancement

SUMMARY: Stock enhancement is used in Japan as a tool to help the replenishment of wild populations of red sea bream Pagrus major . In this study, we analyzed the genetic diversity and composition of wild red sea bream at seven locations around Shikoku Island, South-west Japan, using three microsatellite loci. This analysis was done to test the hypothesis that: (i) red sea bream comprises a single Mendelian population along Japan; and (ii) stock enhancement programs around Shikoku Island are causing genetic differentiation among wild stocks. The results indicated that some locations from the Shikoku area were not significantly different from the rest of Japan, supporting the hypothesis of a single Mendelian population. Significant departures from Hardy–Weinberg equilibrium and significant pairwise F_ST among locations indicated genetic instability within this region. We suggest that the stock enhancement programs made in the region are the possible cause of this genetic instability. A management scheme for the hatcheries involved in the stock enhancement of red sea bream is presented.     

Ultrasonic immunization of sea bream, Pagrus major (Temminck & Schlegel), with a mixed vaccine against Vibrio alginolyticus and V. anguillarum

In order to clarify the effectiveness of ultrasonication on vaccine delivery, juvenile sea bream, Pagrus major , were treated with eight different ultrasonic methods. A mixed vaccine against Vibrio alginolyticus and V. anguillarum was used to immunize the fish . The intensity and frequency of the ultrasound were 280 mW cm^–2 and 35 kHz, respectively. The ultrasonic methods included continuous or pulsed ultrasound for 3 min, and continuous or pulsed ultrasound for 3 min before and/or after immersion for 3 min. Of all the eight ultrasonic methods tested, `pulsed ultrasound followed by immersion' and `immersion, pulsed ultrasound, and followed by immersion again' provided the best protection, which were comparable with protection of fish immunized by intraperitoneal injection. Moreover, the convenience of applying these two ultrasonic methods for immunization was comparable with the immersion method and was much better than intraperitoneal injection. If 2 × 10⁸ CFU mL^–1 of this mixed vaccine was used for vaccination repeatedly five times by ultrasonic methods, it could still produce good protection for the immunized sea bream. Therefore, the ultrasonic method is an effective and practical approach for fish vaccination on a large scale.     

Oxygen deficiency during somitogenesis causes centrum defects in red sea bream, Pagrus major (Temminck et Schlegel)

Vertebral deformities in red sea bream, Pagrus major, remain serious obstacles to the improvement of seedling quality for its aquaculture. However, the causalities of the deformities remain unclear and prevention methods have not yet been established. In this paper, oxygen deficiency during somitogenesis was demonstrated to cause centrum defects (formerly called fused vertebrae in many cases), which are the major vertebral deformity in cultured red sea bream. An induction experiment of centrum defects was conducted by placing fertilized red sea bream eggs under low dissolved oxygen conditions (10.3–16.6%). The low oxygen treatment was carried out for five different developmental stages of embryo: two‐cell stage to blastula stage; gastrula stage; three to 10 somites stage; 11–17 somites stage and 18–24 somites stage. Oxygen deficiency during somitogenesis induced a high incidence of centrum defects. In contrast, it hardly induced centrum defects during the other stages. The dissolved oxygen concentration in the rearing water should be carefully regulated for fertilized eggs, especially during somitogenesis to reduce the incidence of vertebral deformities in the red sea bream.     

Effects of dietary astaxanthin concentration and feeding period on the skin pigmentation of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)

A single‐factor experiment was conducted to investigate the effects of dietary astaxanthin concentration on the skin colour of snapper. Snapper (mean weight=129 g) were held in white cages and fed one of seven dietary levels of unesterified astaxanthin (0, 13, 26, 39, 52, 65 or 78 mg astaxanthin kg^?1) for 63 days. Treatments comprised four replicate cages, each containing five fish. The skin colour of all fish was quantified using the CIE L^*, a^*, b^* colour scale after 21, 42 and 63 days. In addition, total carotenoid concentrations of the skin of two fish cage^?1 were determined after 63 days. Supplementing diets with astaxanthin strongly affected redness (a^*) and yellowness (b^*) values of the skin at all sampling times. After 21 days, the a^* values increased linearly as the dietary astaxanthin concentration was increased before a plateau was attained between 39 and 78 mg kg^?1. The b^* values similarly increased above basal levels in all astaxanthin diets. By 42 days, a^* and b^* values increased in magnitude while a plateau remained between 39 and 78 mg kg^?1. After 63 days, there were no further increases in measured colour values, suggesting that maximum pigmentation was imparted in the skin of snapper fed diets >39 mg kg^?1 after 42 days. Similarly, there were no differences in total carotenoid concentrations of the skin of snapper fed diets >39 mg kg^?1 after 63 days. The plateaus that occurred in a^* and b^* values, while still increasing in magnitude between 21 and 42 days, indicate that the rate of astaxanthin deposition in snapper is limited and astaxanthin in diets containing >39 mg astaxanthin kg^?1 is not efficiently utilized. Astaxanthin retention after 63 days was greatest from the 13 mg kg^?1 diet; however, skin pigmentation was not adequate. An astaxanthin concentration of 39 mg kg^?1 provided the second greatest retention in the skin while obtaining maximum pigmentation. To efficiently maximize skin pigmentation, snapper growers should commence feeding diets containing a minimum of 39 mg unesterified astaxanthin kg^?1 at least 42 days before sale.     

Morphological aspects of feeding and improvement in feeding ability in the early larval stages of red sea bream Pagrus major

The present study examined the appearance, ossification and growth of the bones that form the oral cavity in early larval stages of laboratory reared red sea bream ( Pagrus major ) for 380 h after hatching. The fundamental elements of the oral cavity appeared 11 h after initial mouth opening (HAMO). Development in the red sea bream, based on the osteological development of the feeding apparatus, was divided into three phases following the first feeding (24 HAMO; mean total body length 3.3 mm). The first phase was the early sucking phase (24 to 80–100 HAMO; approximately 3.9 mm), during which the head and bones increased in size. The intensified sucking phase (to 200–220 HAMO; approximately 4.9 mm) was defined by the appearance of new structural elements and a continued enlargement of the head and bones. Finally, during the transition phase (beyond 300 HAMO; approximately 5.6 mm), larvae used grasping as well as sucking to feed, new elements appeared, ossification began, size increased and teeth were acquired. As the larvae advanced through these three phases, the ability to feed by sucking was enhanced by the appearance and growth of new bones. The developmental phases appear to be linked to the transition from endogenous to exogenous nutrition resources under laboratory rearing conditions and to diversification in the size and components of wild food organisms.