Effect of dietary docosahexaenoic acid on lipogenesis and lipolysis in black sea bream,Acanthopagrus schlegeli

Hatchery-roared juvenile black sea breams are characterized by a low level of highly unsaturated fatty acids in their bodies, as compared with wild fish. To assess the effect of docosahaxaenoic acid （DHA） on lipegenic and lipelysis enzymes, one-year fish were roared on a casein-based purified diet and a DHA fortified diet （ 1.5% DHA ethyl ester/kg diet） for 60 d, followed with a period of 55 d for starvation. Dietary DHA was effectively incorporated into the fish body. Fortification of DHA depressed activities of glucose-6-phosphate dehydrogenase and NADP-isocitrate dehydrogenase as lipogenic enzymes in the hepatopancroas and intraperitoneal fat body. Carnitine palmitoyltransferase as lipolysis enzyme in the hepatopancreas was active in the DHA fortified fish. Starvation after feeding experiment induced increased carnitine palmitoyltransferase activity in both control and DHA fortified fish and the activity remained higher in the DHA fortified fish, while the monoenes were selectively consumed prior to highly unsaturated fatty acids. These results indicated that dietary DHA depressed lipogenesis and activated lipolysis.

Microsatellite analysis of variation among wild, domesticated, and genetically improved populations of blunt snout bream （Megalobrama amblycephala）

In the present study, the genetic diversity of one selected strain （Pujiang No. 1）, two domesticated populations （GA and HX） and four wild populations （LZ, YN, SS and JL） of blunt snout bream （Megalobrama amblycephala） was analyzed using 17 microsatellite markers. The results showed that an average of 4.88-7.65 number of alleles （A）; an average of 3.20-5.33 effective alleles （Ne）; average observed beterozygosity （Ho） of 0.6985-0.9044; average expected beterozygosity （He） of 0.6501--0.7805; and the average polymorphism information content （PIC） at 0.5706-0.7226. Pairwise FST value between populations ranged from 0.0307-0.1451, and Nei＇s standard genetic distance between populations was 0.0938-0.4524. The expected heterozygosities in the domesticated populations （GA and HX） were significantly lower than those found in three wild populations （LZ, SS and JL）, but no difference was detected when compared with the wild YN population. Likewise, no difference was found between the four wild populations or two domesticated populations. The expected heterozygosity in Pujiang No. 1 was higher than the two domesticated populations and lower than the four wild populations. Regarding pairwise Fsr value between populations, permutation test P-values were significant between the GA, HX and PJ populations, but not between the four wild populations. These results showed that the expected beterozygosity in the selected strain of blunt snout bream, after seven generations of selective breeding, was lower than that of wild populations, but this strain retains higher levels of genetic diversity than domesticated populations. The genetic differences and differentiation amongst wild populations, domesticated populations and the genetically improved strain of blunt snout bream will provide important conservation criteria and guide the utilization of germplasm resources.

Triterpene-Enriched Olive Extract as an Immunopotentiator in Black Sea Bream(Acanthopagrus schlegelii)

Recently,the use of natural immunopotentiators,such as plant extracts,is predicted to offer high disease-prevention potential in aquaculture.However,few reports on the immunomodulatory impacts of olive extract(OE)on teleost are available.Therefore,the effects of dietary intake of triterpene-enriched OE on black sea bream(Acanthopagrus schlegelii)were investigated in this study.Our data showed that total blood cell counts,in vivo content of lysozyme,activities of antiprotease and myeloperoxidase,and contents of IL-4 and IL-6 were significantly up-regulated by dietary intake of triterpene-enriched OE.Additionally,the hampered immune response induced by cadmium exposure was significantly mitigated by the administration of OE as were indicated by partially or completely rescued immune-relating parameters.Furthermore,the expressions of immune-related genes encoding NF-κB inhibitor alpha(IkBα),tumor necrosis factorα(TNFα),cyclooxygenase-2(COX-2),and proto-oncogene protein c-fos(FOS)were found to be significantly up-regulated by the dietary intake of OE.In general,the results suggested that the dietary intake of triterpene-enriched OE has immune enhancing effect in black sea bream.Such effect may be realized by 1)increasing the total counts of diverse blood cells;2)activating nonspecific immune biomolecules;and 3)affecting signaling pathways such as IKK and ERK and subsequently inducing IL-4 and IL-6 biosyntheses.

Molecular Cloning and Sequence Analysis of IGF-Ⅰfrom Triangular Bream (Megalobrama terminalis)

The insulin-like growth factor Ⅰ(IGF-Ⅰ) gene of triangular bream (Megalobrama terminalis)(GenBank No.AY247412)(Tb)was cloned for the first time from liver by RT-PCR. Thenucleotide sequence analysis showed the Tb IGF-ⅠcDNA consisted of 486 nucleotides andencoded 117 amino acids including B, C, A, D and E five domains. Analysis of E-domainindicated that cloned Tb IGF-Ⅰbelonged to IGF-ⅠEa-2 subtype. Identity analysis showedthe IGF-Ⅰnucleotide sequence shared 99.8% homology with bluntnose bream, 88.8% withgrass carp, 85.8% with common carp; the pre-IGF-Ⅰamine acid sequence shared 99.4% withbluntnose bream, 88.8% with grass carp, 85.4% homology with common carp. In the CyprinusCarpio, the higher homology of nucleotide sequence and amino acid sequence in IGF-Ⅰshowed that the closer relationship the fishes have. These results could provide basicdata for the research on Tb germplasm and the development and utilization of biologicalfeed additives.

Effect of Black Sea bream extracts on cytokine production inlipopolysaccharide-induced inflammation

We investigated the effect of black sea bream extracts on changes in pro-inflammatory and anti-inflammatory cytokines induced by lipopolysaccharide(LPS)in murine splenocytes.The levels of pro-inflammatory cytokines[interleukin(IL)-6,tumor necrosis factor-α(TNF-α),IL-12/IL-23(p40)and IL-17A]and anti-inflammatory cytokines[IL-4,IL-10 and interferon-γ(IFN-γ)]were assessed.Incubation of murine splenocytes with acetone+methylene chloride(A+M)and methanol(MeOH)extracts significantly decreased LPS-induced IL-6,IL-12/IL-23(p40)and IL-17A productions after 6 h incubation(p<0.05).The A+M and MeOH extracts significantly increased LPS-induced IL-4 and IFN-γproductions at 48 and 72 h incubation(p<0.05).Treatment with A+M extract resulted in significantly higher IL-10 production in splenocytes after 72 h(p<0.05).Conclusively,black sea bream extracts were shown to be efficient in falling several pro-inflammatory cytokines while rising anti-inflammatory cytokines.Thus our results suggest that black sea bream extracts selectivity modulate immune events.

Amino Acid Requirements of Gilthead Bream (Sparus aurata) Juveniles

In one trial 360 gilthead bream fingerlings received two different feed mixtures containing two different levels of protein (diet A 400 and B 360 g?kg?1). The average initial live weight was about 2.2 ± 0.1 g fish?1 in each replicate of all treatments. Sixty fish per tank were stocked randomly in 6 fiberglass tanks (1 m3 each). Fish were fed with experimental diets at rate 8% of the body weight daily. The Amino Acids (AA) content was analyzed in the diets, whole fish and muscle at the end of the growth period (60 days). The results indicated that at the end of experiment gilthead bream fingerlings had reached an average live weight 18.5 and 16.2 g fish?1 for fish fed diet A and B respectively. Also the increase of protein levels in the feed to 40% caused a significant increase in the content of Indispensable Amino Acid (IAA) and dispensable amino acid (as %v of whole fish and muscle of wet weight). Two methods were subsequently used to estimate the quantitative IAA requirements of gilthead bream fry based on the hypothesis that (a) the dietary requirement pattern of IAA reflected the tissue pattern and (b) the rate of daily deposition in the fish could be equated with the dietary requirement as percentage of 100 g?1 diet. The quantitative IAA requirement (%) of gilthead bream (Sparus aurata) diets was as follow: Lysine 2.27, Methionine 1.09, Therionine 0.61, Leucine 2.4, Isoleucine 0.47, Histidine1.6, Arginine 1.39, Phenylalanine 1.43, Valine 1.22 and Tryptophane 0.42.

THE EFFECTS OF RECOMBINANT EEL GROWTH HORMONE,METHYLTESTOSTERONE AND L-THYROXINE ON THE GROWTH OF REDSEABREAM,PAGROSOMUSMAJOR

The effects of recombinant eel growth hormone (reGH).methyltestosterone (MT)and L-thyroxine (T4)on the growth of red sea bream. Pagrosomus major.were investigated.Administration of reGH to fry by immersion at 2 mg 1 for 2 hevery 5 dsys resulted in significant increase in both weight and length.but the condition factor (CF) diminished relative to that of similarly treated controls over the 37day treatment period.Immersion in 0.1 mg:1 T4 also resulted in significant increase in both weight and length and higher survival rate of test fry compared to the controls. Immersion in MT had less effect on growth and high-dose resulted in high mortality.In the second study.injection of 2 μg reGH(gwk)caused a significant increase in the specific growth rate (SGR) of test red sea bream fingerlings relative to that of the controls during the 4-week treatment period and maintained the increasing trend over the post-treatment period (weeks 4-6).Injection of MT at a dosage of 1μg (gwk) resulted in a significant

STUDIES ON THE PHOSPHORUS REQUIREMENT AND PROPER CALCIUM/PHOSPHORUS RATIO IN THE DIET OF THE BLACK SEA BREAM(SPARUS MACROCEPHALUS)

An experiment on the phosphorus requirement and the proper Ca/P ratio in the diet of the black sea bream using the phosphorus gradient method (with casein as basic diet, sodium dihydrogen phosphate as source of phosphorus, and calcium lactate as source of calcium) showed that growth was greatly affected by the diet’s phosphorus content and Ca/P ratio. Inadequate phosphorus in the diet resulted in slow growth and poor food conversion ratio (FCR). Analyses of the fish body showed it contained a high level of lipid but a low level of moisture, ash, calcium and phosphorus. The optimal values of phosphorus and Ca/P ratio in the black sea bream diet are 0.68% and 1:2 respectively. Phosphorus in excess of this optimum value resulted in slow growth or even death. The results of this experiment clearly indicated that phosphorus is the principal mineral additive affecting black sea bream growth.

STUDIES ON THE OPTIMUM PROTEIN CONTENT AND THE RATIO OF ANIMAL TO PLANT PROTEIN IN THE DIET OF THE BLACK SEA BREAM(SPARUS MACROCEPHALUS)

An experiment on the optimum dietary protein content for the black sea bream using semi-purified dietsshowed the optimum content is 50.19% by weight as inferred from the growth rate and food consumptionof the fish. Another experiment on the proper ratio of animal to plant protein in its diet using sandeel as theanimal protein source and peanut cake meal as plant protein source showed that the ratio had great ef-fect on its growth and should be 1.00:0.89—0.96 as judged from the growth rate and food consumptionof the fish.

Ontogeny of the immune system in rock bream Oplegnathus fasciatus

Histogenesis of the immune system and specific activity of superoxide dismutase(SOD) were studied in rock bream Oplegnathus fasciatus from fertilization to 50 days after hatching(DAH).The pronephric tubule primordium developed in the embryo,14 h 30 min post fertilization.The spleen anlage was observed between the swim bladder and the intestine at 5 DAH,and the thymus was formed as a paired structure under the pharyngeal epithelium above the gill arch at 10 DAH.The order of the immune organs becoming lymphoid was the pronephric kidney(10 DAH),thymus(15 DAH) and spleen(21 DAH).As the embryo developed,the specific activity of SOD gradually increased until hatching,but subsequently SOD activity continuously decreased to a minimum at 14 DAH.After the spleen became lymphoid,the specific activity of SOD was relatively stable.It is suggested that the immaturity of the lymphoid organs and low specific activity of SOD was the cause of the high mortality of fingerlings 12 to 16 DAH.

Cultivation of Red Sea Bream Pagrus Major Lymphocyte

This study attempted to culture red sea bream lymphocytes using artificial medium supplemented with mitogens and a cytokine. Growth of the lymphocytes was compared between cultures with mitogens phytohemagglutinin (PHA), lipopolysaccharide (LPS), concanavalin A(Con A) and a cytokine mouse interleukin 2(IL 2) in a basal medium at various combinations. Addition of PHA or LPS enhanced growth of the lymphocytes, Con A did not enhance growth so much. Large colonies were formed when PA was added. Con A induced scattered single cell proliferation of the lymphocytes. IL 2 supported the actions of PHA and LPS. Combined addition of PHA and IL 2 maintained proliferation for 30 d.

GROWTH PROMOTION OF RED SEA BREAM, PAGROSOMUS MAJOR, BY ORAL ADMINISTRATION OF RECOMBINANT EEL AND SALMON GROWTH HORMONE

Recombinant eel GH and yeast containing chinook salmon growth hormone (reGH and rcsGH) were incorporated into gelatin and sodium alginate (reGH GS and rcsGH GS) or polymer matrix (reGH HP55) to protect the hormone from proteolytic cleavage in the stomach. The diets containing reGH GS, rcsGH GS, reGH HP55 and free reGH or uncoated rcsGH were administered to red sea bream. Feeding of reGH GS, reGH HP55 and rcsGH GS diets resulted in significant increases in body weight and fork length over those of controls. These results strongly suggest that gelatin and sodium alginate as well as polymer matrix protected the hormone from proteolytic enzymes in the gastrointestinal tract to allow the bioactive hormone to enter the circulation and eventually stimulate fish growth.

Development of Fifteen Novel Microsatellite Markers from Rock Bream (<i>Oplegnathus fasciatus</i>)

Rock bream (Oplegnathus fasciatus) is one of the most economically valuable fish in Korea. In recent years, artificial breeding techniques with molecular and microsatellite markers have been developed to enhance rock bream resources. Microsatellite loci to define genetic diversity were screened in rock bream (n = 30) from Jeju areas of Korea and fifteen polymorphic microsatellite loci were newly identified and analyzed. The number of alleles per locus ranged from 9 to 34 while observed and expected heterozygosity ranged from 0.600 to 1.000 and from 0.772 to 0.977, respectively. These markers will serve as a foundation for future population genetic studies and the selective breeding technology of rock bream farming.

Growth Profile of Gilthead Bream Reared in Mega Flow Re-circulating Aquaculture System

This study was designed to compare the effect of two exchange rates （ERs; 0.5 m^3 feed/kg and 1.5 m^3 feed/kg） in re-circulating aquaculture systems （RAS） on water quality and fish growth profiles on fish stocks （200 indiv/m^3 of 251.4 g e 20.67 g） of gilthead bream, Sparus aurata. Water quality, fish growth, specific growth rate （SGR） and feed conversion ratio under the two ERs were examined for a period of six months. Inorganic nutrient in RAS, temperature, dissolved oxygen and pH were measured daily. Feeding regime effect was also determined on the fish quality and organoleptic characteristics and thus opts to energy optimization of the system. The fish reared under the 1.5 m^3 feed/kg ER demonstrate enhanced growth, the daily SGR and the conversion ratio. Sensory test analysis revealed differences in the organoleptic characteristics between the two experimental fish stocks with considerably high acceptance scores for fish reared at high ER. Nutrient concentrations： ammonia, nitrate, nitrite and phosphate were lower in RAS of the highest ER when compared to those reared under the 0.5 m3/kg feed. Results suggest an ER of 1.5 m^3 feed/kg improved both fish quality and growth profile of the gilthead bream.

Assessment of cadmium,mercury and lead contents of frozen Eurorean sea bass(Dicentrarchus labrax L.,1758)and gilthead sea bream(Sparus aurata L.,1758)fillets from Turkey

In this study, trace metals [Cadmium (Cd), Mercury (Hg) and Lead (Pb)] consentration of 76 pieces of frozen European sea bass (Dicentrarchus labrax Linnaeus-1758) and gilthead sea bream (Sparus aurata Linnaeus-1758) fillets, produced and marketed in Turkey, were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) after microwave damp burning process, and results obtained were assessed in terms of public health. This study was conducted from June 2010 to July 2011. At the end of study, maximum heavy metal levels for sea bass and sea bream fillets were determined as 256.50, 216.22 μg/kg for Cd;414.79, 338.46 μg/kg for Hg ve 1047.61, 147.14 μg/kg for Pb, respectively. At the end of the study, the levels of cadmium (for 3 samples) and lead (for 1 samples) were higher than the recommended legal limits of the European Union for human consumption. It was detected that the fillets which were analyzed was good quality from the point of cadmium, mercury and lead contents.

Characteristics and biological control functions of Bacillus sp.PM8313 as a host-associated probiotic in red sea bream(Pagrus major)aquaculture

Host-associated probiotics(HAPs)are bacteria originally isolated from rearing water or the host's gastrointestinal tract in order to enhance the host's growth and health.This study investigated the HAP potential of Bacillus sp.PM8313,isolated from wild red sea bream(Pagrus major),through characterization and feeding trials.Results based on in vitro tests showed that PM8313 is safe,confirming its hemolytic,cytotoxic,and antibiotic resistance.In addition,PM8313 showed advantages as a probiotic with high viability in the gastrointestinal model and a high cell adhesion rate.Whole-genome sequencing demonstrated that PM8313 has a 4,615,871 bp single circular chromosome and a guaninecytosine content of 45.25%.It also showed the absence of genes encoding virulence factors,such as cytotoxin,enterotoxin,hemolysin,sphingomyelinase,and phospholipase.In the feeding trial,a supplemental diet of 1×10^(8)CFU/g PM8313 positively altered the weight gain,digestive enzyme activity,and intestinal microbiota composition of red sea bream.Analysis of nonspecific immune parameters and immune-related gene expression,and a challenge test showed that PM8313 supplementation increases immunity and pathogenic bacteria resistance.Our findings suggest that PM8313 should be considered for application as a novel HAP to red sea bream aquaculture.

不同贮藏温度下鳊鱼、南美白对虾和花蛤生物胺的比较分析

通过比较鳊鱼、南美白对虾和花蛤在常温(25℃)和冷藏(4℃)下生物胺的差异,并分析生物胺与pH、总挥发性盐基氮(total volatile basic nitrogen,TVBN)、硫代巴比妥酸(thiobarbituric acid,TBA)、菌落总数(total viable counts,TVC)的相关性,旨在研究不同贮藏温度下鱼肉、虾肉和贝肉中生物胺的差异变化,以判断3种水产品在不同贮藏温度下最佳货架期。结果表明,鳊鱼中尸胺和苯丙胺变化最显著(P<0.05),在4℃贮藏8 d最终含量分别为2.94、3.24 mg/kg;在25℃贮藏2 d最终含量分别为20.51、2.48 mg/kg;南美白对虾中腐胺、尸胺和酪胺变化最显著(P<0.05),在4℃贮藏8 d最终含量分别达到了24.65、17.87、6.26 mg/kg,在25℃贮藏2 d最终含量分别为22.02、25.02、13.76 mg/kg;花蛤中腐胺、尸胺和组胺变化最显著(P<0.05),在4℃贮藏8 d最终含量分别为3.04、3.18、1.58 mg/kg,在25℃贮藏2 d最终含量分别为5.68、8.25、2.21 mg/kg。鳊鱼在常温(25℃)和冷藏(4℃)条件下苯丙胺和尸胺均与pH、TVBN、TBA和TVC表现出极显著相关性(P<0.01);南美白对虾中腐胺、尸胺和酪胺均与pH、TVBN、TBA和TVC表现出高度相关性;花蛤中腐胺、尸胺和组胺均与pH、TVBN、TBA和TVC表现显著相关性(P<0.05)。因此可将苯丙胺和尸胺作为鳊鱼的特征生物胺;腐胺、尸胺和酪胺作为南美白对虾的特征生物胺;腐胺、尸胺和组胺作为花蛤的特征生物胺,为以鳊鱼、南美白对虾和花蛤为代表的常食用的鱼虾贝类水产品进行风险监测,提供在运输贮藏保鲜过程中的最佳货架期。

丙三醇联合防腐剂对半干武昌鱼贮藏期间品质的影响

为改善半干武昌鱼货架期短、难以常温流通等问题,以半干武昌鱼为对象,通过测定菌落总数(total viable counts,TVC)、酵母菌和霉菌总数、微生物组成、总挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量、硫代巴比妥酸反应物(thiobarbituric acid reactive substances,TBARS)值、pH值等指标,并结合感官评分,研究丙三醇联合防腐剂对半干武昌鱼贮藏过程中品质的影响。结果表明,随着贮藏时间的延长,丙三醇联合复合防腐剂(0.075%山梨酸钾+0.025%脱氢乙酸钠)处理和对照组半干武昌鱼的感官评分均不断下降,TVC、酵母菌总数、乳杆菌属相对丰度、TVB-N含量、TBARS值、pH值均不断升高。与对照组相比,丙三醇联合防腐剂处理可以减缓半干武昌鱼感官评分下降,抑制细菌和酵母菌生长,减少细菌多样性,降低乳杆菌属细菌相对丰度,减少TVB-N的积累,减缓脂肪氧化速率,并将半干武昌鱼在25、15、4℃下的货架期分别延长2、4、7 d。本研究可为半干武昌鱼的质量控制与货架期延长提供参考。

水分活度降低剂对半干武昌鱼品质的影响

以半干武昌鱼为研究对象,通过测定水分活度(water activity,a_(w))、水分状态、菌落总数(total viable counts,TVC)、酵母菌总数、总挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量、硫代巴比妥酸反应物(thiobarbituric acid reactive substances,TBARS)值及感官评分,研究不同a_(w)降低剂对半干武昌鱼水分状态及品质的影响。结果表明:a_(w)降低剂种类和添加量对半干武昌鱼的a_(w)、水分状态及理化指标有显著影响,且添加量的影响大于种类;海藻糖、山梨糖醇和丙三醇对半干武昌鱼的a_(w)均有一定的降低作用,丙三醇对a_(w)的降低效果最好,添加6%丙三醇时,可将半干武昌鱼的a_(w)从0.917降低至0.873;随着海藻糖、山梨糖醇和丙三醇添加量的增加,半干武昌鱼肉的T_(22)显著减小(P<0.05),T_(23)无显著差异(P>0.05),其不易流动水比例显著增加(P<0.05),而自由水比例显著降低(P<0.05);相对于对照组,随着a_(w)降低剂添加量的增加,半干武昌鱼的TVC、酵母菌总数、TVB-N含量、TBARS值均显著降低(P<0.05),其中6%丙三醇组的各项指标最优。a_(w)降低剂的添加可有效降低水分自由度和流动性,减缓半干武昌鱼品质劣变。

鱼类对乙醇梭菌蛋白中营养物质的表观消化率

试验旨在评价黑鲷(Acanthopagrus schlegelii)和建鲤(Cyprinus carpio var. Jian)对乙醇梭菌蛋白中干物质、粗蛋白、氨基酸、粗脂肪和总磷的表观消化率。试验饲料由70%的基础饲料和30%的乙醇梭菌蛋白组成,并添加0.1%的三氧化二钇(Y_(2)O_(3))作为指示剂。选取平均体重为(6.03±0.09) g的黑鲷360尾,分为两组,每组6个重复,每个重复30尾,两组分别饲喂基础饲料和试验饲料;选取平均体重为(45.00±0.50) g的建鲤180尾,分为两组,每组3个重复,每个重复30尾,两组分别饲喂基础饲料和试验饲料。结果表明,黑鲷对乙醇梭菌蛋白中干物质、粗蛋白、氨基酸、粗脂肪和总磷的表观消化率分为99.89%、100%、95.16%~100%、88.60%和100%;建鲤对乙醇梭菌蛋白中干物质、粗蛋白、氨基酸、粗脂肪和总磷的表观消化率分为78.68%、95.00%、96.12%~100%、52.26%和100%。总体而言,乙醇梭菌蛋白的粗蛋白和氨基酸的表观消化率均处在较高水平。由此可知,对黑鲷和建鲤而言,乙醇梭菌蛋白是较好的单细胞蛋白原料。