棕点石斑鱼(Epinephelus fuscoguttatus♀)×鞍带石斑鱼(Epinephelus lanceolatus♂)F_1染色体制备方法及核型分析

探索了在鱼类大小规格不同情况下制备鱼类染色体的最佳策略和方法,并对棕点石斑鱼(Epinephelus fuscoguttatus♀)×鞍带石斑鱼(Epinephelus lanceolatus♂)杂交子代(俗称珍珠龙胆)的染色体核型进行研究。本研究根据预实验的结果,对所选取的珍珠龙胆幼鱼,采用小鱼游泳法进行前处理,取其鳍条并以冷、热两种不同的滴片方法制备染色体,观察染色体形态并对其染色体核型进行分析。结果显示,选用的染色体制备方法能获得图像清晰、形态良好的细胞分裂相;不同的滴片处理方法细胞分裂指数存在一定差异,即热滴片法的有丝分裂指数为2.58%,明显高于冷滴片法的有丝分裂指数(0.83%),此外,热滴片法所获得的染色体的质量也明显优于冷滴片法。珍珠龙胆石斑鱼二倍体染色体数为48,22对染色体为端部着丝粒染色体,2对染色体为亚端部着丝粒染色体,其染色体臂数(NF)为52,核型公式为2n=48,4st+44t。珍珠龙胆与父本鞍带石斑鱼的染色体数目、核型基本一致,而与母本棕点石斑鱼的核型存在很大差异。研究表明,珍珠龙胆的2n数与其亲本相同,其核型特点符合典型的高位类群鱼类核型特征。在对珍珠龙胆与其亲本的核型进行比较的同时,对已报道的25种石斑鱼进行了核型的比较和综合分析,为石斑鱼的种质鉴定、遗传资源保护利用、育种提供基础资料和理论依据。

恩诺沙星及其代谢产物在珍珠龙胆石斑鱼(Epinephelus fuscoguttatus ♀× Epinephelus lanceolatus ♂)体内的代谢及消除规律

本研究在连续给药的情况下,开展恩诺沙星及其代谢产物环丙沙星在珍珠龙胆石斑鱼体内的代谢残留情况研究,为科学合理使用恩诺沙星防治珍珠龙胆石斑鱼的细菌性疾病提供理论依据,也在水产养殖上为指导恩诺沙星科学用药提供借鉴。在28℃的水温条件下,以30 mg/(kg·bw)恩诺沙星对平均体重为(300±28)g的珍珠龙胆石斑鱼进行连续5 d口灌给药实验,用高效液相色谱-串联质谱法测定石斑鱼血浆、肌肉和肝脏中恩诺沙星及其代谢产物环丙沙星的残留含量。结果显示:恩诺沙星在血浆、肝脏和肌肉中很快达到最大值,达峰时间分别为第5天给药后3 h、第5天给药后3 h和第4天给药后3 h,其浓度分别为24.5 mg/L、13.0 mg/kg和8.20 mg/kg;恩诺沙星的代谢产物环丙沙星分别在第5天给药后3 h、第5天给药后3 h和第4天给药后3 h达到峰值,其浓度分别为0.276 mg/L、0.738 mg/kg和0.110 mg/kg,说明只有少量的恩诺沙星代谢成环丙沙星。根据本实验的数据,建议休药期不低于980度日。

Effects of Temperature and Salinity on Oxygen Consumption and Ammonium Excretion Rate of ♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus Juveniles

The impact of water temperature(24, 27, 30 and 33℃) and salinity(15, 20, 25, 30 and 33) on oxygen consumption(OCR) and ammonium excretion rate(AER) of ♀ Epinephelus fuscoguttatus ×♂ E. lanceolatus hybrid grouper juveniles(9.39 ± 0.07 g) were investigated under the fed and un-fed conditions. The results showed that the OCR and AER were significantly(P < 0.05) affected by temperature and salinity under both fed and un-fed conditions. When temperature was 24–33℃, the OCR and AER of fed hybrid grouper juveniles were 85.68%–129.52% and 125.78%–287.63%, respectively, higher than those of un-fed hybrid grouper juveniles. The O/N ratio, protein use(P_u), Q_(10)(respiration) and Q_(10)(excretion) of fed hybrid grouper juveniles were 14.43–24.01, 28.35% – 48.48%, 1.69 and 3.01, respectively. The O/N ratio, P_u, Q_(10)(respiration), Q_(10)(excretion) of un-fed hybrid grouper juveniles were 20.39 – 31.79, 22.16% – 34.34%, 1.23 and 1.17, respectively. When salinity was 15–33, the OCR and AER of fed hybrid grouper juveniles increased by 87.42% – 116.85% and 215.38% – 353.57%, respectively, over those of un-fed hybrid grouper juveniles. The O/N ratio and P_u of fed hybrid grouper juveniles were 14.48 – 17.78, 39.36% – 49.43%, respectively. The O/N ratio and Pu of un-fed hybrid grouper juveniles were 20.39 – 31.79 and 22.16% – 34.34%, respectively. The specific dynamic action(SDA) of hybrid grouper juveniles was mainly related to protein metabolism. The results had a guiding significance to the large-scale intensive aquaculture of hybrid grouper juveniles.

虎龙杂交斑(Epinephelus lanceolatus♂×E. fuscoguttatus♀)对20种常见氨基酸的嗅觉电生理反应

虎龙杂交斑(Epinephelus lanceolatus♂×E.fuscoguttatus♀)是我国重要的石斑鱼养殖品种,为研究其对20种常见氨基酸的不同嗅觉反应,筛选出对虎龙杂交斑嗅觉具有高效刺激性的单体氨基酸,通过嗅上皮水下嗅电位法(electro-olfactogram,EOG)得出了虎龙杂交斑对20种常见氨基酸的嗅觉反应差异和对5种氨基酸的嗅觉反应阈值,并讨论了氨基酸分子结构与嗅觉刺激效果之间的关系。结果表明:氨基酸的种类和浓度均对虎龙杂交斑嗅觉刺激反应有影响,虎龙杂交斑对含5~6个碳原子、无支链的中性脂肪族含硫氨基酸反应强烈,一个例外是对含3个碳原子的半胱氨酸有较强反应。10^(-6)mol/L的蛋氨酸刺激液对虎龙杂交斑嗅觉的刺激性最强,10^(-2)mol/L脯氨酸刺激液对虎龙杂交斑嗅觉的刺激性最弱。虎龙杂交斑嗅觉反应幅值(y)随5种氨基酸刺激液浓度对数值(x)的增大而呈指数升高趋势,在试验中虎龙杂交斑嗅觉反应幅值没有随5种氨基酸刺激液浓度对数值的增大而达到平台期。从反应阈值中反应幅值与氨基酸刺激液浓度的关系方程式可得出反应阈值浓度为10;~10;mol/L。研究结果有助于为虎龙杂交斑诱食剂和饲料配制的研究提供依据。

闽南地区紫石斑(Epinephelus lanceolatus)幼鱼爆发性传染病的病原学研究

应用RT PCR技术,检测了福建南部石斑鱼育苗场患病紫石斑鱼的病原,结果检出神经坏死病毒;对该病毒的RT PCR产物进行了核酸测序和序列分析,与基因库中马拉巴斑和紫石斑神经坏死病毒编码病毒核衣壳蛋白的基因片段序列的同源性大于97%.病原菌分离鉴定结果,有2菌株分别是溶藻弧菌和豚鼠气单胞菌,对实验动物有一定的毒力.药敏试验表明这些菌株对常用抗生素表现耐药.临床症状和实验结果都表明,神经坏死病毒感染是导致石斑鱼大批死亡的主要原因,而溶藻弧菌和豚鼠气单胞菌应为继发感染,加重了病情,使更多的石斑鱼死亡.

鞍带石斑鱼Epinephelus lanceolatus卵子的短期保存

在水产养殖中,建立体外保存卵子的方法对于人工授精和种苗生产具有重要的应用价值。鞍带石斑鱼Epinephelus lanceolatus是我国重要的水产养殖鱼类,其受精卵价格昂贵。本研究探讨了保存条件(保存介质、温度和pH)与添加剂(鞍带石斑鱼血清、维生素预混料)对于鞍带石斑鱼卵子短期保存的影响。结果表明,22℃时,卵子在L-15培养基(pH=8.1)中保存2 h,受精率和孵化率分别为66.4%和47.9%。在此基础上,添加鞍带石斑鱼血清和维生素预混料可以有效地延长保存时间,卵子能维持较高的活力。在体外保存8 h后,卵子的受精率和孵化率仍可达到64.4%和44.8%。本研究通过优化改良,建立了一种适合于鞍带石斑鱼卵子体外短期保存的体系,有助于鞍带石斑鱼的育种工作和孵化管理。

Characterization of the Complete Mitochondrial Genome of the Hybrid Epinephelus moara♀ × Epinephelus lanceolatus♂,and Phylogenetic Analysis in Subfamily Epinephelinae

This study presents the complete mitochondrial genome of the hybrid Epinephelus moara♀× Epinephelus lanceolatus♂. The genome is 16886 bp in length, and contains 13 protein-coding genes, 2 r RNA genes, 22 t RNA genes, a light-strand replication origin and a control region. Additionally, phylogenetic analysis based on the nucleotide sequences of 13 conserved protein-coding genes using the maximum likelihood method indicated that the mitochondrial genome is maternally inherited. This study presents genomic data for studying phylogenetic relationships and breeding of hybrid Epinephelinae.

Study on Embryonic Development, Larva,Juvenile and Young Fish of Epinephelus fuscoguttatus

This study aimed to study the development characteristics of Epinephelus fuscoguttatus at the embryo, larval, juvenile and young fish stages, thereby improving the breeding efficiency of E. fuscoguttatus. [Method] The morphological characteristics and embryonic and post embryonic development of E. fuscoguttatus, including the occurrence and development of nervous system, digestive system and circulatory system, were observed and analyzed using eggs self-fertilized with artificially induced spawning in the breeding base of Hainan Province. [Result] The fertilized egg of E. fuscoguttatus is spherical, colorless transparent with single oil ball, and its diameter ranges from 0.83 to 0.94 mm. Based on the development process, the embryonic development of E. fuscoguttatus was divided into six stages, namely fertilized egg stage, cleavage stage, blastula stage, gastrula stage, idiosome formation stage and hatching stage. The entire embryonic development of E. fuscoguttatus required 20 h 47 min in the sea water with temperature of 28.4-31.9℃ salinity of 31-32 and pH of 8.4, and the total cumulative temperature was 455.361 ℃·h. The post embryonic development of E. fuscoguttatus was divided into larval stage, juvenile stage and young fish stage based on the features of the yolk-sac, second dorsal fin spine, pelvic fin spine, and body color. Accordingly, the larval stage was further classified into pre-larva and post-larva, with or without yolk-sac, respectively. The extension and shrinkage of the first pelvic fin spine and the second dorsal fin spine as well as the spinules on aforementioned spines were the most significant changes during the post embryonic development of E. fuscoguttatus. [Conclusion] This study will provide some basic data for industrial breeding of E. fuscoguttatus.

A Preliminary Study on Fertilization Biology between Epinephelus coioides(♀) and Epinephelus lanceolatus(♂)

Crossbreeding between Epinephelas coioides （ ♀ ） and Epinephelus lanceolatus （♂） was conducted by artificial insemination. Fertilized eggs were col- lected at 0, 30, 90 s, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 min post-insemination respectively, which were fixed by Smith＇s solution, embedded by paraffins and stained by H.E. According to the characteristics of Epinephelus coioides eggs, tissue section method was modified. The results showed that the sperms of Epinephelus lanceolatus rapidly entered the eggs of Epinephelus coioides at 30 s - 1 rain post-insemination. Observation results of tissue sections showed that mature eggs of Epinephelus coioides remained at metaphase of secondary maturation division. The eggs were activated after sperm penetration into the egg. With the develop- ment of secondary maturation division, at 2 rain post-insemination, eggs reached the metaphase of secondary maturation division ; at 3 - 6 rain post-insemination, sperm asters appeared; at 5 min post-insemination, eggs extruded secondary polar body; at 7 -15 rain post-insemination, male pronucleus and female pronucleus moved closer to each other and fused finally, forming a clear junction line; subsequently, zygote nucleus formed and karyotheca became faint; at 15 min pest-insem- ination, first karvokinetic division was develoued.

Effects of Temperature and pH on Embryonic Development and Survival Rate of Newly Hatched Larvae of Epinephelus fuscoguttatus

The effects of temperature and pH on embryonic development and survival rate of newly hatched larvae of Epinephelus fuscoguttatus were discussed by single factor experiment method. Under a salinity of 31‰, fertilized eggs were incubated at different temperatures （17, 20, 23, 26, 29 （eontrol）, 32, 35 ℃ ） and different pH values （5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.4 （control）, 8.5, 9.0, 9.5 and 10.0）, the development rate of fertilized eggs, hatching rate, deformity rate, survival rate of newly hatched larvae, and optimum temperature and pH ranges for embryonic development were recorded and analyzed. The results showed that the incubation period y required by fertilized eggs was in remarkably negative correlation with temperature x, y =4 017. 3x-15277 , R2 =0. 971 3. At 29 ℃, the hatching rate was the highest, up to 92.00% ; this temperature was corresponding to the lowest deformity rate of newly hatched larvae （ 1.09% ） ; corresponding effective accumulative temperature was also the lowest （437. 410 ℃ . h）, and significantly different from other experimental groups （P 〈 0.05 ） ; but on the contrary, corresponding survival rates at 24 and 48 h reached, respectively, 88.03% and 82. 97% which were significantly different from other experimental groups （ P 〈 0.05）. At the pH of 8.4 in the CK group and the pH of 8.5 of one experimental group, the embryonic development rates were the highest; con-esponding hatching rates of fertilized eggs were the highest, respectively, of 88.33% and 83.33% which were significantly different from other groups （P 〈 0.05） ; and corresponding survival rates at 24 and 48 h were the highest, and reached 90.84% and 85.03%, respectively. In the pH range of 8.0 - 8.5, the deformity rate of newly hatched larvae was 0. It was indicating that for embryonic development of E. fuscoguttatus, the suitable water temperature value was in the range of 17 - 29 ℃, the optimum value was in the range of 23 -29℃; and the suitable pH value was in the range of 6.5 -9.5, and the optimum value was in the range of 8.0- 8.5.

Soybean meal as a source of protein in formulated diets for tiger grouper, <i>Epinephelus fuscoguttatus</i>juvenile. Part II: Improving diet performances

The present study was conducted as a continuation of our previous study on the effects of fish meal replacement with soy bean meal, SBM in the diets of tiger grouper, Epinephelus fuscoguttatus which revealed the possible level of fish meal protein replacement of 30% with positive effect of phytase supplementation in one of the test diet. In the present study, all experimental diets with SBM inclusion (10%, 20%, 30%, 40% replacement levels) were supplemented with phytase and fed to juvenile tiger grouper with initial body weight of 44.57 ± 0.28 g for eight weeks. Apart from the effects on growth performance, diet utilization and fish whole-body composition, apparent digestibility coefficient of diets was also measured. Similar findings to our previous experiment were observed in the present study. Diet SM40P (40% replacement level) had produced the poorest growth performance and feed conversion ratio (FCR). However, it was observed that FCR of SM40P was improved when compared to SM40 (without phytase) in our previous experiment. Other than that, SBM-based diets were performed as good as the control diet in terms of growth, feed utilization and survival rate. Replacement of fish meal did not significantly influence body composition, except for whole body lipid content in SM40P. In general, dry matter and protein apparent digestibility coefficients (ADC) of the test diets were influenced by SBM inclusion in the diets. However, crude lipid ADC was very high in all dietary treatments indicating efficient utilization of dietary lipid by juvenile tiger grouper. The findings of the present study confirmed that SBM can be used to replace FM at a level of up to 30% and supplementation of phytase in SBM-based diets is recommended to improve the diet performance.

Soybean meal as a source of protein in formulated diets for tiger grouper, <i>Epinephelus fuscoguttatus</i>juvenile. Part I: Effects on growth, survival, feed utilization and body compositions

The effects of fish meal (FM) replacement with graded level of soybean meal (SBM) on growth performance, feed utilization, survival rate and body composition were investigated in juvenile tiger grouper, Epinephelus fuscoguttatus (initial body weight 13.9 ±0.65 g). Six experimental diets were formulated to contain 50% crude protein, 16% crude lipid and 365.8 kcal/100g feed with SBM replacing FM protein at 0% (SM 0), 10% (SM 0), 20% (SM 20), 30% (SM 30), 40% (SM 40) and 20% with phytase (SM 20P) replacement levels. At the end of the ten-week feeding trial, there were no significant differences detected in terms of growth performances (weight gain and specific growth rate), feed conversion ratio (FCR) and survival rates of fish fed with the control diet (SM 0), SM 20, SM 30 and SM 20P. Net protein utilization of fish fed SM 20P was higher than those fed with other diets suggesting an improved utilization of nutrients with phytase addition in the diet. Replacements of FM protein with SBM at 10% and 40% have resulted in significantly lower growth and poorer FCR than other replacement levels. Survival rates remain high (≥90%) throughout the trial. Whole-body proximate composition of the fish was significantly affected by the inclusion of SBM in the diets. It can be concluded that 20%-30% of FM protein replacement with SBM is recommended and addition of phytase in the SBM-based diet should be considered to improve nutrient utilization of tiger grouper juvenile.

Molecular Characterization and Expression Analysis of SKIV Infection of Interferon-Induced Protein with Tetratricopeptide Repeats 1(IFIT1) in Epinephelus lanceolatus

Interferon-induced protein with tetratricopeptide repeats 1(IFIT1), also known as interferon-induced protein 56(IFI56) or Interferon-stimulated protein 56(ISG56), was originally identified as a protein induced upon treatment with interferon and inhibited by viral replication and translational initiation. In this study, Epinephelus lanceolatus IFIT1(ELIFIT1) gene was cloned for the first time. The complete cDNA of El IFIT1 gene includes 2921 nucleotides, and encodes a 437-amino acid(AA) protein. The putative ELIFIT1 protein has 9 TRP domains and is highly similar with IFIT1 proteins in other teleosts. In healthy fish, ELIFIT1 gene was highly expressed in the blood, which indicate its specific function in the peripheral immune system. Its expression was also observed in various immunity-related tissues including spleen, intestine, and kidney, Inducted with spotted knifejaw iridovirus(SKIV), ELIFIT1 gene expression was upregulated in the spleen, kidney, and liver 24 h after induction and reached its peak at 72 h, indicating that ELIFIT1 may play an important role in antivirus. These findings contribute to the understanding of the antiviral regulation of ELIFIT1 gene in teleost.

Host gut-derived Bacillus probiotics supplementation improves growth performance, serum and liver immunity, gut health, and resistive capacity against Vibrio harveyi infection in hybrid grouper(♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatus)

Several reports have revealed the vital role that probiotics play in fish growth and health.However,few works are available for host gut-derived probiotics on the growth,immunity,and gut microbiota of fish,especially in hybrid grouper (♀Epinephelus fuscoguttatus×♂Epinephelus lanceolatus) due to their isolation difficulty and functional verification.This study aimed at assessing 3 host gut-derived Bacillus species?effects on the growth,immune and antioxidant-biochemical responses,haematological parameters,intestinal morphology,immune-related gene expression,gut microbiota,and disease resistance against Vibrio harveyi in hybrid grouper.A total of 480 hybrid grouper (initial weight=9.03±0.02 g) were randomly allotted into 4 groups,namely,the group fed a basal diet without probiotic inclusion (control,B0),the group fed the basal diet with Bacillus velezensis GPSAK4 (BV),the group fed the basal diet with Bacillus subtilis GPSAK9 (BS),and the group fed the basal diet with Bacillus tequilensis GPSAK2 (BT) strains at 1.0×10^(9)CFU/g.After a 6-week feeding trial,the results revealed significant improvements (P<0.05) in the growth performance,whole fish-body proximate composition,blood haematological parameters,serum,liver,and intestinal biochemical indexes,intestinal morphology,and protection against V.harveyi pathogen in the probiotic-treated groups compared with the untreated.Additionally,the expressions of intestinal tight junction genes (occludin and ZO1),pro-and anti-inflammatory genes,including IL1β,IL6,IL8,TNFa,MyD88,IL10,and TGFβ,were upregulated (P<0.05) after Bacillus species administration.Host gut-derived Bacillus supplementation shaped the gut microbiota by significantly increasing (P<0.05) the relative abundance of Proteobacteria,Bacteroidetes,Actinobacteria (except the BS group),Acidobacteria(except the BT group),Cyanobacteria (except the BV and BT groups),and Verrucomicrobia phyla,as well as known beneficial genera (Romboutsia,Turicibacter,Epulopiscium,Clostridium_sensu_stricto 1 and 13,Lactobacillus,and Bacillus),but significantly decreased (P<0.05) the abundance of Firmicutes,Chloroflexi,and Fusobacteria phyla,and purported pathogenic genera (Staphylococcus and Photobacterium) compared with the control group.Collectively,the results suggest that B.velezensis GPSAK4,B.subtilis GPSAK9(especially this strain),B.tequilensis GPSAK2 dietary supplementation at 1.0×10^(9)CFU/g has positive effects on the intestinal health of hybrid grouper via microbial composition modulation,thus enhancing the assimilation and absorption of nutrients to boost fish growth,immunity,and disease resistance.

Soybean protein concentrate causes enteritis in juvenile pearl gentian groupers(Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂)

Due to diminishing fish meal(FM)supplies,superb protein(PRO)sources are needed for aquaculture,such as soy-based PRO.However,these can cause enteritis and even intestinal injury in fish when used at high proportions in feed.This research examines the effects of substituting soybean protein concentrate(SPC)for FM on the growth performance and intestinal balance of pearl gentian groupers and investigates the mechanism of SPC-induced enteritis.Experimental fish(n=720)were fed 1 of 3 following diets:(1)a 50%FM diet(control),(2)a diet with 20%of the FM substituted with SPC(group SPC20),and(3)a 40%SPC-substituted diet(SPC40).Fish were fed for 10 wk iso-nitrogenous(50%PRO)and iso-lipidic(10%lipid)diets.Groups SPC20 and SPC40 showed significantly lower developmental performance and intestinal structures than control.Group SPC40 had significantly higher expressions of pro-inflammatory-related genes,such as interleukin 1β(IL1β),IL12,IL17 and tumor necrosis factorαand significantly lower expressions of anti-inflammatory-related genes,such as IL5,IL10 and transforming growth factorβ1.Biochemical and 16S high-throughput sequencing showed that the abundance and functions of intestinal flora in group SPC40 were significantly affected(P<0.05),and there were significant correlations between operational taxonomic unit abundance variations and inflammatory gene expressions at genus level(P<0.05).The second-and third-generation full-length transcriptome sequence was used to analyze the mechanism of SPC-induced enteritis in pearl gentian groupers,which showed that enteritis induced by SPC may be caused by disturbances to intestinal immune function induced by an imbalance in intestinal nutrition and metabolism,such as the intestinal immunity network for IgA production pathway.However,it remains unclear as to which intestinal immune or nutritional imbalance is most important in enteritis development.This study provides a basis for further research into soy PRO-related enteritis in fish.

Immunity,feed,and husbandry in fish health management of cultured Epinephelus fuscoguttatus with reference to Epinephelus coioides

Groupers are dispersed worldwide in the tropical and subtropical waters.They are prized in the live reef fish trade,making them candidates with high market value and consumer demand.In the Asian-Pacific region,the brown-marbled grouper(Epinephelus fuscoguttatus)is widely adapted as an aquaculture species.However,health management remains a major concern in the stressful intensive culture process.The present review discusses techniques and current knowledge in the cultivation of E.fuscoguttatus towards healthy fish growth focusing on aspects of immunity,feed,and husbandry.Understanding how the fish immune system responds during infections provides insights into the intricate ways fish resist pathogens.This information is helpful when developing vaccination strategies or immunostimulant compounds to strengthen fish immunity.Feeds that are formulated according to the needs of the fish ensure optimal growth and using suitable alternative ingredients may lower production cost without compromising fish health.Good husbandry practices contribute to a favourable environment for the fish to grow,while interspecific hybridization may be a convenient approach to generate hardier species.Nevertheless,it has been noted that research in E.fuscoguttatus is relatively scarce in contrast to the closely-related orange-spotted grouper(E.coioides),which is used in the present article as a reference.Ultimately,the identified gaps in knowledge between the two species warrant species-specific research in E.fuscoguttatus to promote fish health and ensure continued success in aquaculture.

两种重要经济石斑鱼肠道微生物群落结构及代谢功能的比较分析

为揭示虎龙杂交斑(Epinephelus fuscoguttatus♀×E.lanceolatus♂)和斜带石斑鱼(Epinephelus coioides)肠道微生物群落的结构及功能差异,利用16S rDNA高通量测序技术对其肠道微生物群落进行分析。结果表明:(1)虎龙杂交斑肠道微生物群落以变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和放线菌门(Actinobacteria)为主,斜带石斑鱼中以变形菌门、梭杆菌门(Fusobacteria)和厚壁菌门为主。(2)在属水平,虎龙杂交斑和斜带石斑鱼肠道中均含有高丰度的弧菌属(Vibrio)。鲸杆菌属(Cetobacterium)、发光杆菌属(Photobacterium)和丙酸菌属(Propionigenium)是斜带石斑鱼肠道中的标志微生物,而虎龙杂交斑肠道中的标志微生物为棒状杆菌属1(Corynebacterium 1)、变形杆菌属(Proteus)、葡萄球菌属(Staphylococcus)和类香菌属(Myroides)。(3)网络分析显示,变形菌门在两种石斑鱼肠道中均占主导地位。(4)功能预测表明,虎龙杂交斑肠道微生物群落中抗坏血酸与糖醛酸代谢、植物-病原体相互作用和胰岛素信号通路显著高于斜带石斑鱼,斜带石斑鱼肠道微生物群落的功能在万古霉素类抗生素和链霉素生物合成、亚油酸代谢、双酚降解以及类黄酮生物合成的相关途径中显著富集。研究结果有望加深对石斑鱼肠道微生物群落的认识,为选择合适的石斑鱼养殖品种,提高石斑鱼养殖产业的经济效益提供科学参考。

投喂频率对珍珠龙胆石斑鱼生长性能、免疫、血清及肝脏生化指标的影响

本试验旨在研究投喂频率对珍珠龙胆石斑鱼(Epinephelus fuscoguttatus♀×E.lanceolatu)生长性能、免疫、血清及肝脏生化指标的影响。在摄食高脂饲料的条件下,采用4种投喂频率(1、2、3、4次/d)投喂初始质量为(11.51±0.02)g的石斑鱼56 d,共360尾,每种投喂频率设3个重复,每个重复1个0.3 m 3玻璃钢桶,每桶30尾鱼。结果表明:1)1次/d组石斑鱼终末体质量(FBM)、增重率(WGR)及特定生长率(SGR)显著低于其他各组(P<0.05),其他各组间无显著差异(P>0.05)。2次/d组饲料系数(FCR)最低,显著低于1次/d组(P<0.05)。投喂频率对石斑鱼脏体比(VSI)、肝体比(HSI)与肥满度(CF)无显著影响(P>0.05)。2)1次/d组血清甘油三酯(TG)含量显著低于其他各组(P<0.05)。各组间血清总胆固醇(TC)含量无显著差异(P>0.05)。随着投喂频率的升高,血清低密度脂蛋白(LDL)含量呈逐渐降低趋势,在1次/d组有最大值,显著高于其他各组(P<0.05),血清高密度脂蛋白(HDL)含量则呈相反趋势,在1次/d组有最小值,显著低于其他各组(P<0.05),血清过氧化氢酶(CAT)与超氧化物歧化酶(SOD)活性呈上升的趋势,在4次/d组有最大值,显著高于其他各组(P<0.05)。血清总抗氧化能力(T-AOC)呈先上升后稳定的趋势,3、4次/d组显著高于1、2次/d组(P<0.05)。3)1次/d组肝脏T-AOC,CAT、SOD、溶菌酶(LYS)活性及免疫球蛋白(IgM)含量显著低于其他各组(P<0.05)。4)4次/d组肝脏TG含量显著高于其他各组(P<0.05)。1次/d组肝脏TC含量显著高于其他各组(P<0.05)。4次/d组肝脏极低密度脂蛋白(VLDL)含量显著低于其他各组(P<0.05)。4次/d组肝脏脂蛋白脂酶(LPL)活性显著高于其他各组(P<0.05),肝脏肝脂酶(HL)活性呈现上升趋势,3、4次/d组显著高于1、2次/d组(P<0.05)。3次/d组肝脏甘油三脂酶(ATGL)活性显著高于其他各组(P<0.05)。综上所述,适宜的投喂频率能提高石斑鱼的生长性能、抗氧化能力和脂代谢能力。本试验条件下,摄食高脂饲料石斑鱼的最佳投喂频率为2次/d。

饲料中添加乳杆菌对杂交石斑鱼生长性能及肠道健康的影响

为了研究饲料中添加乳杆菌对杂交石斑鱼(Epinephelus fuscoguttatus♀×Epinephelus polyphekadion♂)生长性能、健康的影响,选取450尾初始平均体重为(89.55±0.75)g的杂交石斑鱼幼鱼,随机分为5组,按照对照组(CG)饲喂基础饲料,试验组(EG)在基础饲料中分别按照0.8%(EGⅠ)、1.2%(EGⅡ)、1.6%(EGⅢ)、2.0%(EGⅣ)的比例添加亿菌优(植物乳杆菌与嗜酸乳杆菌含量比2∶1)进行养殖.养殖8周后,分析各组杂交石斑鱼生长性能、血清生化指标、消化酶活性及肠道菌群情况.结果显示:(1)EG组增重率、特定生长率及饲料系数与CG相比均无显著差异(P>0.05);(2)血清生化指标中,EGⅡ组的谷丙转氨酶活性,EGⅢ组总蛋白含量、谷丙转氨酶活性、谷草转氨酶活性、总胆固醇含量及甘油三酯含量,EGⅣ组碱性磷酸酶活性及谷丙转氨酶活性均显著高于CG组(P<0.05);(3)杂交石斑鱼肠道淀粉酶活性随着饲料中添加乳杆菌水平的增加呈现先升高后降低的趋势,EGⅢ组肠道淀粉酶含量最高(P<0.05),其他消化酶活性在EG组与CG组间无显著差异(P>0.05);(4)EGⅢ组杂交石斑鱼肠道菌群的ACE指数、Chao1指数、Shannon指数及Simpson指数与对照组相比均无显著差异(P>0.05),但厚壁菌门(Firmicutes)丰度显著高于对照组(P<0.05).因此,饲料中复合添加植物乳杆菌与嗜酸乳杆菌对于杂交石斑鱼血清中部分与代谢相关的生化指标及肠道消化酶活性等均有显著影响,可丰富和优化肠道菌群.

虎龙杂交斑循环水育苗系统设计及应用效果

为了进一步研究封闭式循环水养殖系统在海水鱼育苗生产过程中应用的可行性,采用物质平衡相关原理,结合循环水养殖水处理设施设备构建技术,优化了水处理工艺流程并设计了生物滤器体积与循环量等关键参数,构建了一套封闭式可控型循环水育苗系统。设计了2路水处理环路,集成构建了育苗池双排水、竖流沉淀、移动床生物过滤等高效水处理技术和装备。使用该育苗系统开展虎龙杂交斑(Epinephelus lanceolatus♂×E.fuscoguttatus♀)育苗试验,重点考虑溶氧、pH和氨氮3个水质指标及全长、体质量和出苗率3个生长指标。结果显示:仔稚鱼生长情况良好,平均全长(75.1±0.55)mm,平均体质量(9.2±0.42)g,出苗率16.28%。水质检测结果显示:温度26.8~27.7℃,溶氧6.6~7.2 mg/L,pH平均为8.31、总氨氮平均质量浓度为(0.183±0.191)mg/L,水质情况良好。经济性分析结果显示:单茬利润1.86万元,年利润5.58万元(按1年3茬计),具有良好的经济效益。该研究可为工厂化循环水育苗系统应用及推广提供技术支持。