This study evaluated the effects of Lactobacillus plantarum LP37 and florfenicol (FF) on growth performance, immune response, and nutritional metabolism in Sebastes schlegelii. Four experimental groups of fish were established: a control group (CK, basal diet), LP37 group (basal diet + 10(9) CFU/g LP37), FF group (basal diet + 20 mg/kg FF), and FF-LP37 group (FF-supplemented diet for 15 days, followed by LP37-supplemented diet for 15 days). Serum, liver, and kidney samples were collected for biochemical and molecular analyses. The FF-LP37 group exhibited the highest weight gain and specific growth rates (SGRs) than those in the CK group (p < 0.05). Antioxidant indices showed that superoxide dismutase (SOD) activity was evaluated in LP37 and FF-LP37 groups; catalase (CAT) activity increased in FF group serum and FF-LP37 group liver (p < 0.05); total antioxidant capacity (T-AOC) was higher in all supplemented groups than in CK (p < 0.05); malondialdehyde (MDA) levels were elevated in the FF group (p < 0.05). Nutritional metabolism-related enzymes (hexokinase [HK], pyruvate kinase [PK], phosphoenolpyruvate carboxykinase [PEPCK], glutamine synthetase (GS), glucokinase, phosphoglucomutase, lipoprotein lipase [LPS], and fatty acid synthase [FAS]) were significantly altered, particularly in LP37 and FF-LP37 groups (p < 0.05). Molecular analysis revealed that expression of interleukin-1 receptor-associated kinase 4 (IRAK-4) and myeloid differentiation primary response 88 (MYD88) in the liver and kidney was upregulated in the FF group (p < 0.05), but downregulated in the LP37 and FF-LP37 groups compared with CK. In conclusion, dietary supplementation with LP37, FF, or the FF-LP37 sequence improved S. schlegelii growth, AOC, immunity, and nutritional metabolism, providing valuable insights for aquaculture dietary strategies.

Maccullochella peelii peelii, the largest endemic freshwater fish in Australia, is a valuable species with considerable aquaculture potential. Despite its ecological and economic importance, its genome and phylogenetic history have been poorly studied due to a lack of genomic resources. In this study, we present the first comprehensive whole-genome survey and de novo assembly of M. peelii peelii. K-mer distribution analysis estimated the genome size to be 744.31 Mb, with a heterozygosity of 0.18% and a repetitive sequence content of 42.22%. The final assembled genome size reached a size of 731.74 Mb, and the assembly completeness was assessed by BUSCO, and the resulting score was 87.88%. The mitochondrial genome spans 16,422 bp, with a GC content of 42.05%, and contains 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes. Phylogenetic analysis, based on orthologous single-copy genes and conserved mitochondrial genes, places M. peelii peelii within a monophyletic clade, in strong agreement with traditional morphological classifications. PSMC analysis reveals significant fluctuations in effective population size over the past million years, including a sharp bottleneck around 400 Kya, followed by recovery during the Last Interglacial Period (~130–116 Kya), likely driven by habitat improvements. These findings provide a critical genomic resource to address reproductive bottlenecks and enhance molecular breeding programs for this species.

Members of Bacillus cereus have been documented as important bacterial pathogens in aquaculture. However, scarce information is available on B. cereus isolates as causal pathogens of big-belly seahorses Hippocampus abdominalis. In the present study, a B. cereus isolate (SH1), recovered from a disease outbreak on a seahorse farm, was identified as a bacterial pathogen of big-belly seahorses, and its pathogenic potential in terms of pathogenicity-related factors, antimicrobial resistance, and virulence were analyzed. The isolate possessed beta-hemolytic and proteolytic activities, and harbored 31 pathogenicity-related genes, including 20 virulence genes inhA, alo, cytK, hblA, hblC, hblD, nheA, nheB, asbA, asbB, asbC, asbD, asbE, asbF, dhbA, dhbB, dhbC, dhbE, dhbF, and hal encoding exoenzymes, exotoxins, and nutritional/metabolic factors, as well as 11 resistance genes BcI, BcII, BcIII, EF-Tu, vanR, vanS, mphM, satA, rpoB, fosB, tet(45) conferring resistance to beta-lactams, elfamycins, glycopeptides, macrolides, nucleosides, rifamycins, phosphonic acids, and tetracyclines. Furthermore, the isolate correspondingly displayed phenotypic resistance to chephalosporins and penicillins and showed in vivo virulence to big-belly seahorses with the seven-day median lethal dose (LD50) value of 1.51 & times; 10(6 )CFU/mL. To our knowledge, this is the first study to describe B. cereus as a pathogen of big-belly seahorses. The findings of this study underscore the need for targeted management of B. cereus infection in seahorses.

Feeding frequency is a critical factor in Penaeus monodon aquaculture. This study aimed to investigate the effects of an intelligent high-frequency feeding strategy on the growth, intestinal microbiota, and metabolism of Penaeus monodon, a 35-day trial was conducted comparing a high-frequency (HF, 72 times/day) and a low-frequency (LF, 4 times/day) feeding regime using an intelligent feeding system. The physiological and mechanistic responses were assessed through 16S rDNA sequencing and metabolomics. The HF group demonstrated significantly superior growth performance, with markedly higher final body weight, length, WGR, AGR, and SGR, alongside a lower feed conversion ratio (FCR) than the LF group. Intestinal analysis revealed that the HF group possessed higher microbial diversity and a distinctly different community structure compared to the LF group. Beneficial families like Rhodobacteraceae and Lachnospiraceae were enriched in the HF group, whereas the LF group was dominated by Vibrionaceae. Metabolomic profiling showed that the HF group exhibited significant upregulation of key metabolites (e.g., L-alanine, citric acid) compared to the LF group, which were enriched in pathways central to amino acid metabolism and energy production. Correlation analysis further linked these shifts in beneficial microbiota with the altered metabolic profile. These comparative results demonstrate that high-frequency feeding reshapes the intestinal microbiome and host metabolism in P. monodon, providing a mechanistic explanation for its growth-promoting effects.

Under global climate change, extreme high-temperature events are becoming increasingly frequent, posing a major threat to the sustainability of aquaculture by disrupting physiological homeostasis and driving summer mortality syndrome in ectothermic crustaceans. To elucidate the adaptive response mechanisms of the commercially important swimming crab Portunus trituberculatus under acute thermal stress and to provide theoretical support for aquaculture risk prevention, this study systematically investigated the physiological, transcriptional, and metabolomic responses of P. trituberculatus exposed to 38 °C acute thermal stress. The results showed that 38 °C high temperature induced severe oxidative stress, and the organism activated multiple defensive mechanisms to cope with it. The glutathione (GSH)-centered non-enzymatic antioxidant system served as the core defense, effectively scavenging reactive oxygen species and maintaining redox balance. The enzymatic antioxidant system was activated during the early stage of stress but declined in the late stage, with malondialdehyde (MDA) content increasing significantly, indicating irreversible oxidative damage. The heat shock response and ubiquitin-proteasome system played synergistic protective roles; however, down-regulation of heat shock protein (HSP) expression rendered the ubiquitin-proteasome system a major compensatory mechanism. Additionally, the oxidative phosphorylation pathway was significantly activated to provide sufficient energy for stress responses. The aminoacyl-tRNA biosynthesis pathway was significantly enriched at both transcriptional and metabolic levels, facilitating the synthesis of antioxidant and repair-related proteins. Nevertheless, exposure to 38 °C high-temperature stress markedly down-regulated the upstream amino acid metabolites required for protein synthesis. Overall, 38 °C acute thermal stress exceeded the thermal tolerance limit of P. trituberculatus, causing severe damage to DNA and cells, while the organism relied on multiple defensive mechanisms to resist stress. These findings provide a reference for the cultivation of heat-tolerant varieties and the improvement of aquaculture management.

Maccullochella peelii, commonly known as Murray cod, is an endemic economic fish from the Australian freshwater systems. In order to provide high-quality reference genome for its genomic studies, we assemble and annotate the first near telomere-to-telomere genome of this species which spans 762.84 Mb with a contig N50 of 31.21 Mb, 99.02% sequences were positioned to 24 chromosomes by Hi-C assembly. After gap filling using ONT ultra-long reads, yielding 22 gapless chromosomes. Based on homologous predictions and RNA-sequencing, 27,380 protein-coding genes were identified, and the functions were predicted for 24,998 (91.3%) of them. Moreover, assembled genome was evaluated as 99.3% single-copy BUSCOs completeness. This work could provide a foundation and high-quality genomic resources for the future research on molecular breeding and population genetics of this species.

This study investigated the impacts of white spot syndrome virus (WSSV) on the gut microbiota of Penaeus monodon through a comparative microbiota analysis of infected and healthy shrimp using 16S rDNA sequencing. The WSSV-infected shrimp exhibited characteristic white spots, reduced feeding activity, and behavioral lethargy preceding 100% mortality. The comparative microbiota analysis revealed a significantly diminished α-diversity in the infected specimens, marked by phylum-level dominance shifts from Proteobacteria (72.68%) and Firmicutes (11.27%) in the controls to Cyanobacteria (75.51%) and Proteobacteria (15.63%) in the WSSV-infected shrimp. An LEfSe analysis identified Arthrospira_PCC-7345 and Halochromatium as significantly enriched taxa during infection, contrasting with depleted populations of Ruegeria, Marivita, Bacillus, and seven other genera. The distinct dysbiosis pattern characterized by the pathogen-favored taxa proliferation and commensal species suppression demonstrates WSSV-associated microbiota restructuring, potentially contributing to disease progression in farmed P. monodon. These findings establish intestinal microbial biomarkers for early WSSV detection in aquaculture systems.

Shewanella putrefaciens is a vital bacterial pathogen implicated in serious diseases in Chinese mitten crab Eriocheir sinensis. Yet the use of probiotics to improve the defense ability of E. sinensis against S. putrefaciens infection remains poorly understood. In the present study, the protective effect of dietary R. sphaeroides against S. putrefaciens infection in E. sinensis was evaluated through antioxidant capability, immune response, and survival under bacterial challenge assays, and its protective mechanism was further explored using a combination of intestinal flora and metabolome assays. Our results indicated that dietary R. sphaeroides could significantly improve immunity and antioxidant ability of Chinese mitten crabs, thereby strengthening their disease resistance with the relative percentage survival of 81.09% against S. putrefaciens. In addition, dietary R. sphaeroides could significantly alter the intestinal microbial composition and intestinal metabolism of crabs, causing not only the reduction of potential threatening pathogen load but also the increase of differential metabolites in tryptophan metabolism, pyrimidine metabolism, and glycerophospholipid metabolism. Furthermore, the regulation of differential metabolites such as N-Acetylserotonin positively correlated with beneficial Rhodobacter could be a potential protection strategy for Shewanella infection. To the best of our knowledge, this is the first study to illustrate the protective effect and mechanism of R. sphaeroides supplementation to protect E. sinensis against S. putrefaciens infection.

Red abdominal shell disease is a major disease that has caused significant economic losses in Chinese soft-shelled turtle Pelodiscus sinensis aquaculture. Yet scarce information is available on Aeromonas dhakensis as a causal agent of red abdominal shell disease in P. sinensis. In the present study, a haemolytic and proteolytic A. dhakensis isolate (F04) was demonstrated as a causative agent of red abdominal shell disease in cultured P. sinensis. It carried virulent aerolysin, heat-labile cytotoxic enterotoxin, polar flagella, and lipase-encoding genes aer, alt, flaA, and lip, exhibited the mean lethal dose (LD50) value of 4.27×105 CFU/ml in P. sinensis, and developed multiple resistances against aminoglycosides, chloramphenicols, cephalosporins, lincosamides, macrolides, penicillins, peptides, sulfonamides, and tetracyclines antimicrobials. To our knowledge, this is the first study to identify a multiply resistant A. dhakensis strain as a pathogen of red abdominal shell disease in P. sinensis, and the findings of this study can also provide valuable insights into the virulence and antimicrobial resistance in Chinese soft-shelled turtle-pathogenic A. dhakensis.

The use of phagostimulant and Rhodobacter has been well proposed in Chinese mitten crab Eriocheir sinensis culture. Yet the influence of phagostimulant supplementation on the growth-promoting and defensive effects of Rhodobacter on Chinese mitten crabs is still unknown. In this study, a 40-day feeding trial was carried out to examine the contribution of dietary phagostimulant MTSG to the effects of R. azotoformans on the growth performance, immunity, antioxidant capability, intestinal flora diversity, and resistance of E. sinensis to bacterial challenge. The results revealed higher weight gain, specific growth rate, as well as serum and hepatopancreatic acid phosphatase, alkaline phosphatase, superoxide dismutase, and catalase activities in the 3.0 to 9.0 g/kg diet MTSG + R. azotoformans-fed crabs than R. azotoformans-fed crabs, indicating that the supplementation of MTSG at 3.0 to 9.0 g/kg diet could improve the effect of R. azotoformans on growth performance, immunity and antioxidant capability of Chinese mitten crabs. Furthermore, the supplementation of MTSG at 3.0 to 9.0 g/kg diet could strengthen the effect of R. azotoformans on intestinal flora diversity of Chinese mitten crabs, and enhance the effect of R. azotoformans on the disease resistance against S. putrefaciens infection. To the best of our knowledge, this is the first study to reveal the contribution of a phagostimulant (MTSG) to the growth-promoting and defensive effects of R. azotoformans on Chinese mitten crabs.

为探讨亚硝态氮(NO2-N)慢性胁迫对斑节对虾(Penaeus monodon)(非洲群体,以下称金刚虾)生理特性的影响,本实验以体质量为(6.06士0.76)g的金刚虾为研究对象,测定不同NO2-N浓度下金刚虾的行为、非特异性免疫以及消化功能.研究显示,NO2-N浓度≤6 mg/L时,金刚虾的活力、摄食不受影响;NO2-N浓度≥8 mg/L时,金刚虾摄食缓慢、游动异常、胃肠道模糊;NO2-N浓度为14 mg/L时,金刚虾开始死亡.金刚虾肝胰腺中脂肪酶(Lipase)、胰蛋白酶(Trypsin)活性在NO2-N浓度为6 mg/L时达到最大值,之后开始下降,当NO2-N浓度升至14 mg/L时活性最低,与对照组差异显著.NO2-N浓度由0上升至14 mg/L,血淋巴谷胱甘肽(GSH)含量、酸性磷酸酶(ACP)活性呈"先升高后下降"的趋势,谷草转氨酶(GOT)、谷丙转氨酶(GPT)的活性则呈"先升高后下降再升高"的趋势,NO2-N浓度为6 mg/L时,GHS、ACP活性达到最大值;NO2-N浓度为14 mg/L时,GOT、GPT活性达到最大值,与对照组差异显著.综合以上结果,工厂化养殖金刚虾时,建议将水体中NO2-N浓度控制在6 mg/L以下.

Penaeus monodon（African group） accommodates industrial aquaculture and has promising market prospects. But the deterioration of water quality causes frequent occurrence of diseases. Nitrite is a common pollutant,and the experiment was conducted to observe its effect on oxidative stress, energy metabolism and osmotic regulation. Four gradients of nitrite concentrations（0.1, 5, 10 and 15 mg/L） were set for 4 groups, and three parallels were set for each group. After the acute stress experiment for 72 hours, enzyme activities or substance content were assayed.（1） As for oxidative stress factors in gill, activities of SOD, GSH-Px, CAT and NOS increased initially and decreased subsequently. At 24 h, the activities of SOD, GSH-Px and NOS reached maximum. The activities of SOD and GSH-Px in the 10 mg/L group and NOS activity in 15 mg/L group were significantly higher than other groups. On the contrary, MDA content in stress groups was the lowest at 24 h, and the 10 mg/L group was significantly lower than other groups. At 48 h, CAT activity reached the maximum, and the CAT activity of 10mg/L group was significantly higher than other groups. At 72 h, the NO content reached maximum, and 15 mg/L group was significantly higher than other groups.（2）The indicator of serum energy metabolism, LPS, increased at first and decreased then. The activities of HK, PFK, PK or TG content, decreased obviously during stress process.At 48 h, LPS activity reached maximum, and 10 mg/L group was significantly higher than other groups. At 72 h,the activities of HK, PFK, PK and TG content reached minimum, 15 mg/L group were significantly lower than those of other groups.（3）The gill osmotic regulation parameters, Na + , K + -ATPase, decreased during whole process.At 72 h, the Na + , K + -ATPase activity reached the minimum, and the 15 mg/L stress group was significantly lower than other groups. Results showed that P. monodon could improve antioxidant capacity, enhance lipid absorption and utilization, and disturb osmotic balance when exposed to acute nitrite stress. But only within certain concentration or time limits can it come into play. The result will provide data support for the further exploration of molecular mechanisms and also provide theory support for healthy prawn farming.

Litopenaeus vannamei is one of the important crustaceans in aquaculture in China. In recent years, the shrimp culture industry has gradually developed into an intensive and high-density model, which can lead to environmental deterioration and large-scale outbreak of diseases. The widespread use of antibiotics has led to the increase of pathogen drug resistance, environmental pollution, and ecological imbalance, resulting in secondary pollution in the water. Probiotics are live microbial additives that promote good health and are environmentally sustainable and safe for use. They are often used as important substitutes for antibiotics. Brevibacillus laterosporu, as a biocontrol probiotic, is commonly used for disease control of crops, animals, and poultry, but its use is rarely reported in aquaculture. A 28-day breeding experiment was carried out with L. vannamei weighing (1.00±0.08) g, to study the effects of adding B. laterosporu FAS05 in the feed on the growth, disease resistance, and immunity of L. vannamei. The experiment was divided into four groups with three replicates in each group, and 50 shrimps in each replicate were fed with the experimental feed supplemented with 0 CFU/g (group C, as the control group), 105 CFU/g (group BL1), 107 CFU/g (group BL2), and 109 CFU/g (group BL3) of B. laterosporu FAS05. B. laterosporu FAS05 was isolated from the aquaculture pond with a low number of Vibrio in summer. The bacterium was added into the basic feed with fish meal, soybean meal, and corn meal as the main protein source, fish oil and phospholipid oil were added as the fat source, wheat flour as the main sugar source, and inorganic salts and vitamins as supplements. L. vannamei was purchased from a prawn farm in Weihai City, Shandong Province. The temperature was 25–28 ℃ and the salinity was 27–30. During the breeding experiment, eight shrimps were randomly selected in each tank every two weeks and their body length, weight, and plumpness were measured. The phagocytic activity assay was modified on the basis of the method reported by Delaporte et al (2003). Fl-1 channel flow cytometry was used to detect and analyze the offset of respiratory burst peak. The blood lymphocytes, serum, and hepatopancreas of shrimp were collected 24 hours after the experiment. The activities of immune related enzymes in hepatopancreas, such as superoxide dismutase (SOD), catalase (CAT), acid phosphatase (ACP), and alkaline phosphatase (ALP) levels, and the activities of immune related enzymes in serum, phenol oxidase (PO), and lysozyme (LZM), were determined by kits. The phagocytic activity was measured, and the assay was modified on the basis of Delaporte et al (2003). Fl-1 channel flow cytometry was used to detect and analyze the offset of respiratory burst peak. After the feeding test, a one-week infection test of Vibrio parahaemolyticus was carried out to determine disease resistance. The experimental results were expressed as Mean±SD. One-way ANOVA analysis was conducted for all data using statistical software SPSS 16.0, and significance level was defined as P < 0.05. LSD homogeneity of variance test was used to compare the differences between experimental treatment groups and control groups. The results showed that there was no significant difference in survival rate among all groups (P > 0.05), and the body length, body weight, and specific growth rate of shrimps in the BL1 and BL2 groups were significantly higher than those in group C (P < 0.05). Compared to that in group C, the abundance of Vibrio in the aquaculture water in the BL1 to BL3 groups was significantly decreased (P < 0.05). After infection with V. parahemolyticus, the survival rate of group C was about 45%, while the survival rate of the BL1 to BL3 groups was more than 80%; therefore, the survival rate of the BL1 to BL3 groups was significantly higher than that in group C (P < 0.05), and no significant difference was found among the BL1 to BL3 groups (P > 0.05). Compared to that of group C, the phagocytizing rate of shrimp blood cells in the BL1 to BL3 groups increased significantly (P < 0.05), while the production of ROS in blood cells decreased significantly (P < 0.05). The LZM, CAT and ACP activities of shrimps in the BL1 to BL3 groups were significantly higher than those in group C (P < 0.05). There was no significant difference in LZM and ACP activities among the BL1 to BL3 groups (P > 0.05). The PO of shrimps in the BL2 group was significantly higher than those in other groups (P < 0.05). The ALP and SOD in the BL1 and BL2 groups were significantly higher than those in group C and BL3 (P < 0.05). The above results showed that B. laterosporu FAS05 as a feed additive could promote the growth of shrimp, activate the immune system, improve disease resistance, and inhibit the growth of Vibrio in the surrounding environment. The reference dosage was 105 CFU/g. When the infection is serious, the dosage can be increased to 107 CFU/g to further improve the non-specific immunity of shrimp. The results of this study can provide basic data for the application of B. laterosporu FAS05 in shrimp culture and production.

The development of microbial communities is important for the growth of the fat greenling Hexagrammos otakii; however, the relationship between microbial communities and fish diet is poorly understood. Here, we used metagenomics sequencing to investigate the gut microbiota of H. otakii at three key time points during development. The gut microbial diversity and community composition of H. otakii presented stage-specific signatures and appeared to shift with different diets and environmental conditions such as NH4 + -NO2- etc. Metagenomics analysis indicated that the dominant phyla were Proteobacteria and Firmicutes. With dietary changes from rotifers and Artemia to formulated feed, the dominant genera shifted from Vibrio and Photobacterium to Lactococcus, and variations in the gut microbiota increased with age. Based on metagenomics functional annotation using the Kyoto Encyclopedia of Genes and Genomes database, growth and diet at different stages affected the metabolic function of the gut microbiome by activating carbohydrate and amino acid metabolism while weakening lipid and nucleotide metabolism. In addition, as predicted by the Carbohydrate-Active enZymes database, glycoside hydrolase and glycosyl transferases may be involved in food degradation. Our results suggest that the H. otakii gut microbiota assembly was coupled to animal development and host age-associated biotic features and changes. Diet had a considerable effect on these distinct communities at different times, indicating that the fish gut microbiota rapidly adapted to dietary shifts. The microbiota therefore likely plays an indispensable role in nutrient turnover and fermentation. These findings can provide guidance for the development of probiotics and the application of feed additives.

In this study we sequenced the genomes of three economically important swimming crabs Portunus trituberculatus, Charybdis japonica , and Callinectes sapidus using the next-generation sequencing approach and made a basic assembly. The genomes of the three species are characterized with high heterozygosity (>1.2%) and high repeat content (>50%). Genome comparative analysis revealed 40 long conserved fragments (>5,000 bp) among the three species, most of them are involved in cardiac-related biological process. Relative higher genome similarity was found between P. trituberculatus and C. japonica that are belong to different subfamilies, compared to that between P. trituberculatus and C. sapidus which are from the same subfamily. It is inconsistent with their phylogenetic evolutionary trees inferred from previous mitochondrial DNA coding fragments and a conserved ANK2 protein fragment from this study. We speculated that the high genome similarity between P. trituberculatus and C. japonica might be attributed to their same inhabit range in which the genome is subject to the same environment selection, and the inconsistence between genome similarity and phylogenetic relationship is caused by the different evolutionary rates of coding DNA and non-coding DNA under environment selection.

为调查山东某水蛭养殖场病情暴发原因,从该场患病水蛭中分离得到优势菌株SZ-1,对其进行生理生化特性及分子生物学分析.形态学、生理生化分析显示,菌株SZ-1为革兰氏阴性菌,杆状,两端钝圆,有鞭毛;Biolog GenIII分析表明,该菌株生长代谢利用情况与假单胞菌属吻合,与荧光假单胞菌B特征相似.基于16S rRNA基因序列分析同源性,该菌株16S rRNA基因序列与荧光假单胞菌(Pseudomonas f luorescens)相聚类,聚合置信度可达99％.综合生物学及分子特征,判定SZ-1为荧光假单胞菌.

[目的]解析斑节对虾(Penaeus monodon)(非洲群体)(俗称"金刚虾",以下同)携带耐药菌及耐药基因现状.[方法]本研究从山东滨州北海新区采集了金刚虾,对其肠道细菌常用抗生素的耐药菌性质及数量、占比及种类进行检测,通过荧光定量PCR技术分析肠道内容物样品中的4类抗生素的4种耐药性基因分布特征.[结果]肠道中可培养细菌总数约1.45×105-2.13×106 CFU/g,有四环素、萘啶酸、氟苯尼考、庆大霉素4种抗生素耐药菌的检出,其中喹诺酮类萘啶酸耐药菌占比最高,达到35.00％,氨基糖苷类庆大霉素占比最少.10种抗生素药敏性质分析表明,肠道可培养细菌对庆大霉素、氟苯尼考等6种抗生素高度敏感,对四环素、卡那霉素中度敏感,对萘啶酸、青霉素、阿莫西林耐药.从分离的耐药菌鉴定结果可以得出,可培养的抗生素耐药菌主要集中在弧菌属,基于属水平的不同抗生素耐药菌统计显示,不同抗生素耐药菌种类存在明显差异,且同一菌属有耐多种抗生素的情况.荧光定量PCR检测分析,4种耐药基因的丰度不同,tetA基因相对拷贝数和四环素耐药菌比例、floR基因和氟苯尼考耐药菌比例之间存在显著相关性(P＜0.01);qnrA基因相对拷贝数和萘啶酮酸耐药菌比例、aadA基因相对拷贝数和庆大霉素耐药菌比例之间均不存在显著相关性(P＞0.01).[结论]本研究说明,金刚虾肠道微生物中存在一定的耐药菌和耐药基因,具有携带风险.

虾虹彩病毒病是一种感染甲壳类的急性、传染性疾病,其病原为虹彩病毒科的一个新属即十足目虹彩病毒属的十足目虹彩病毒1(Decapod iridescent virus 1,DIV1).DIV1传播速率快、宿主范围广、致死率高,近年来在对虾养殖过程中广泛流行,给我国对虾养殖业造成巨大经济损失.目前,对DIV1引发的虾虹彩病毒病的病原学、病理学、流行病学、检测诊断等方面已开展了部分研究,但对病毒感染的分子机制、宿主的应答规律等还知之甚少.本文对DIV1的发现过程、分类地位、形态特征、感染特性、机体响应机制、基因组信息、宿主范围、传播途径及检测方法等方面的最新研究进展进行了综述,阐述了疾病防控及未来展望,以期为虾虹彩病毒病的深入研究及有效防控提供参考.

基于斑节对虾(非洲群体)(Penaeus monodon)肠道菌的生理生化特性,为解决斑节对虾急性肝胰腺坏死综合征(AHPND)提供新思路,文章分离纯化健康斑节对虾肠道中的优势菌株;以致病性哈维氏弧菌为指示菌,用牛津杯法从纯化菌株中筛选拮抗菌;通过生理生化特征、Biolog系统鉴定及16S rDNA技术综合方法对菌株进行鉴定;通过药敏实验,评价拮抗菌株的安全性;绘制高敏拮抗菌株的生长曲线,得出其生长特性;通过测定其产酶活性,形成对其益生机制的初步推断.从斑节对虾肠道中共分离得到14株的优势土著菌,分别标记为P.m-1、P.m-2······P.m-14,经过拮抗实验得到了3株拮抗菌(P.m-1、P.m-9和P.m-13).经鉴定P.m-1、P.m-9和P.m-13分别为枯草芽孢杆菌(Bacillus subtilis)、屎肠球菌(Enterococcus faecium)和溶藻弧菌(Vibrio alginolyticus).药敏实验结果表明,3株拮抗菌均不属于耐药菌,P.m-1对药物高度敏感.生长特征实验表明:P.m-1在2h进入对数期,10h达到生长高峰,菌体密度可达1.14×109 cfu/mL,表现出了强劲的生命力.经过蛋白酶活性测定,P.m-1具有较强的产酶能力.优势菌P.m-1具有成为益生菌的潜力,后续将作为功能性饲料添加剂或水质调节剂进行应用,为AHPND进行生物防治提供新思路.

针对对虾养殖过程水处理的研究现状和瓶颈问题,文章综述了国际和国内重要的水处理管理理念与策略,主要包括:养殖用水"减法"管理理念、投入品"减法"管理理念、基于微生物的水处理策略和基于不同营养级的生物水处理策略等.较全面地探讨了养殖节水、生态调水、精准投喂、补偿生长、生物饵料、生物过滤器、水动力等对于水处理的重要性.并建议建立基于对虾福利生物学的水处理评价体系,联合生物行为变化、生态生理指标、水体理化指标进行综合评价.该综述期望为对虾产业和水产养殖的可持续发展提供新思路和可行路径.