This study conducted a 70-day feeding trial to evaluate the effects of dietary Lactobacillus plantarum supplementation (0, 0.1, 1.0, and 10.0 g/kg) in red claw crayfish (Cherax quadricarinatus). Growth performance, hepatopancreatic antioxidant-related parameters, and the expression of genes related to the Toll/Imd and JAK-STAT pathways were determined. Results showed that dietary L. plantarum supplementation significantly improved weight gain rate, specific growth rate, daily growth index, and feed efficiency, which were increased by 23.57%, 5.10%, 9.67%, and 7.90%, respectively, and reduced mortality rate by 60.00% compared with the control group (p < 0.05), enhanced the activities of glutathione peroxidase, catalase, superoxide dismutase and total antioxidant capacity, and reduced malondialdehyde levels in the hepatopancreas (p < 0.05). Furthermore, dietary L. plantarum supplementation was associated with the upregulated expression of key genes related to the Toll/Imd and JAK-STAT signaling pathways (p < 0.05). The expression levels of tumor necrosis factor-α, interleukin-1β, and transforming growth factor-β1 were also significantly increased (p < 0.05). Overall, these findings suggest that dietary L. plantarum supplementation improved growth performance and antioxidant-related and immune-related parameters in red claw crayfish, and that these effects were associated with the upregulated expression of genes involved in the Toll/Imd and JAK-STAT pathways. Among the tested treatments, 1.0 g/kg L. plantarum produced the most favorable overall response.

The objective of this research was to examine how varying dietary inclusion levels of Lactobacillus plantarum influence the muscle composition, hemolymph biochemical indices, lipid metabolism, and the mTOR signaling pathway in red claw crayfish (Cherax quadricarinatus). Four diets with 0 (CK), 0.10 (LG), 1.00 (MG), and 10.00 (HG) g/kg L. plantarum were formulated, with three replicates of 40 crayfish (average weight: 0.13 ± 0.01 g, average length: 0.58 ± 0.01 cm) in a 56-day trial. Results showed that no significant differences in muscle crude protein, crude lipid, ash, or moisture were observed between experimental and CK groups (p > 0.05), while the contents of multiple essential amino acids (e.g., arginine up to 6.05%, histidine up to 7.52%) and non-essential amino acids (e.g., aspartic acid up to 3.70%, glutamic acid up to 1.76%) were significantly elevated, and the content of muscle C18:0 (a saturated fatty acid) was notably reduced (p < 0.05), while total saturated fatty acids showed no significant variation among all groups (p > 0.05). Hemolymph alkaline phosphatase, transaminases, lactate dehydrogenase, and lysozyme activities, as well as glucose, total protein, and albumin levels, were significantly higher in experimental groups (p < 0.05). Lipid metabolism was upregulated, and the mTOR pathway was inhibited in experimental crayfish (p < 0.05). This study demonstrates that dietary L. plantarum enhances lipid metabolism in red claw crayfish, with 1.0 g/kg L. plantarum identified as the optimal supplementation level.

In intensive freshwater aquaculture, total ammonia nitrogen (TAN) accumulation and low dissolved oxygen (DO) frequently co-occur, yet the mechanisms underlying their chronic combined hepatotoxicity remain unclear. In this study, juvenile grass carp were exposed for 8 weeks to TAN (0, 3, or 9 mg/L) under normoxic or low-DO conditions. Co-exposure impaired growth, elevated serum AST, ALT, IL-1β, and TNF-α, and aggravated hepatic lipid peroxidation, antioxidant-capacity decline, histopathological lesions, and ultrastructural damage. Co-exposure activated TLR4/NF-κB-related inflammatory signaling and induced ER stress/UPR-related responses, including increased grp78, perk, eif-2α, xbp1s, and atf6 expression. It also suppressed mitochondrial biogenesis- and respiration-related genes, including pgc-1α, tfam, nrf1, cox1, and cycs, increased hif-1α and fis1, and promoted apoptosis-associated responses characterized by higher caspase3, caspase9, and bax expression and lower bcl2 expression. Metabolomics further revealed broader amino acid- and lipid-related metabolic imbalance. Collectively, oxidative stress-associated intracellular homeostasis disturbance appears central to TAN–hypoxia hepatotoxicity, highlighting the need for coordinated TAN and DO management in intensive aquaculture.

This study investigated the effects of dietary Rhodotorula mucilaginosa supplementation with different concentrations (0.0 g/kg, 0.1 g/kg, 1.0 g/kg, 10.0 g/kg) on red claw crayfish (Cherax quadricarinatus). Four groups were established: control group (CK, 0.0 g/kg), low-dose group (HL, 0.1 g/kg), medium-dose group (HM, 1.0 g/kg), and high-dose group (HH, 10.0 g/kg). The feeding trial lasted for 56 days. The results showed that, compared with the control group, all supplementation groups exhibited significantly reduced feed conversion ratios (p < 0.05). The HM and HH groups demonstrated significant increases in body length growth rate, specific growth rate, weight gain rate, hepatosomatic index, and survival rate (p < 0.05). All supplemented groups showed significantly enhanced trypsin and lipase activities in intestines and trypsin activity in the hepatopancreas (p < 0.05). The HM and HH groups exhibited elevated α-amylase activity in the hepatopancreas (p < 0.05). Compared with the control group, marine red yeast supplementation reduced colonization of potential pathogens while increasing probiotic abundance, effectively improving intestinal microbiota structure. The HM group significantly improved intestinal villus length, width, and muscular thickness (p < 0.05). All supplemented groups showed considerable upregulation of hepatopancreatic genes related to immunity (heat shock protein 70, down syndrome cell adhesion molecule, crustacean antibacterial peptide, serine proteinase inhibitors, crustacean hyperglycemic hormone, anti-lipopolysaccharide factor, lysozyme, and alkaline phosphatase) and antioxidant defense (superoxide dismutase, glutathione peroxidase, glutathione, and catalase) (p < 0.05). These findings indicate that R. mucilaginosa can significantly enhance digestive enzyme activity, maintain intestinal health, improve antioxidant and immune-related gene expression, and promote growth performance in red claw crayfish, with the HM group (1.0 g/kg R. mucilaginosa) showing optimal promotion effects.

White spot syndrome virus (WSSV) has emerged as a significant threat to global shrimp aquaculture, causing economic losses because of its rapid spread and high mortality rates. This study aims to elucidate the genetic and evolutionary dynamics of WSSV through a comprehensive genome analysis. Utilizing 27 complete genome sequences sourced from public databases, this study investigates the genetic variability, potential recombination events, and evolutionary patterns of WSSV. Our results identified multiple genomic deletions, 14 novel single-nucleotide polymorphism sites, and variable number tandem repeats across different strains, underscoring the virus’s genetic diversity. A recombination event between freshwater and marine strains highlights a complex transmission pathway, potentially facilitated by aquaculture practices. A phylogenetic tree constructed using ancestral genes suggests that WSSV originated in Southeast Asia and subsequently globally spread, influenced by both natural and anthropogenic factors. Genomic shrinkage of the virus occurred in time series, while the host’s viral infection induced transposon transposition and insertion into the earlier virus genome to provide a basis for genomic shrinkage. Our research emphasizes the importance of advanced molecular characterization and evolutionary models of the virus in understanding the spread of viral pathogens in aquaculture environments.

This study investigated the effects of dietary supplementation with varying levels (CK: 0.0 g/kg; RL: 0.1 g/kg; RM: 1.0 g/kg; RH: 10.0 g/kg) of Rhodotorula mucilaginosa on muscle composition, serum biochemical indicators, antioxidant capacity, lipid metabolism, and the mTOR signaling pathway in red claw crayfish (Cherax quadricarinatus). Results showed that, compared to CK, treatment groups had higher muscle crude protein, fat, leucine, histidine, arginine, and essential amino acids (p < 0.05), and lower saturated fatty acids (p < 0.05). Treatment groups also exhibited increased activities of alkaline phosphatase, acid phosphatase, superoxide dismutase, catalase, glutathione S-transferase, lysozyme, albumin, total protein, and antioxidant capacity (p < 0.05), with reduced activities of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and triglycerides (p < 0.05). In the hepatopancreas, treatment groups showed significant downregulation of AMP-activated protein kinase α, β, and γ, and carnitine palmitoyltransferase 1 genes (p < 0.05). Conversely, genes involved in lipid anabolism (peroxisome proliferator-activated receptor γ, acetyl-CoA carboxylase, fatty acid synthase, sterol regulatory element-binding protein, protein kinase B, and mammalian target of rapamycin 1 and 2) were upregulated (p < 0.05). In conclusion, R. mucilaginosa supplementation affects muscle composition, lipid metabolism, and mTOR signaling. The optimal dose is 1.0 g/kg.

Macrobrachium rosenbergii (M. rosenbergii) is a vital freshwater economic species, and no prior reports exist on its infection by the symbiotic flatworm Temnocephala digitata (Platyhelminthes: Temnocephalidae; T. digitata). However, during aquaculture practices, we observed that T. digitata infection caused growth retardation and even mortality in M. rosenbergii. This study investigates the pathogenic mechanisms of T. digitata infection in M. rosenbergii using a multi-omics approach. Results revealed that T. digitata infection induced growth retardation, immune suppression, and metabolic dysregulation in the shrimp. Intestinal microbiota analysis demonstrated microbial dysbiosis characterized by an increased abundance of Proteobacteria (particularly the opportunistic pathogenic genus Aeromonas) and reduced proportions of Firmicutes and Bacteroidota. Integrated transcriptomic and metabolomic analyses showed that T. digitata infection suppressed ribosomal functions, lipid metabolism, and protein metabolism in gill tissues while concurrently activating inflammatory factors and pathways (e.g., TNF-alpha, COX-2, and Toll/IMD signaling). Additionally, infection induced abnormal molting behavior by upregulating ecdysone (ECD), and methyl farnesoate (MF) while suppressing molt-inhibiting hormone (MIH), exacerbating energy depletion and immune exhaustion. Multi-omics correlation analysis further elucidated complex interactions among core gut microbiota, key metabolites, and hub genes, collectively driving nutrient-immune imbalance. Histopathological examinations confirmed hepatopancreatic vacuolization, intestinal villi atrophy, and gill lesions, consistent with metabolic and immune dysfunction. This study provides the first evidence of T. digitata-associated pathogenicity in M. rosenbergii, revealing that the symbiont-host interaction disrupts nutrient metabolism-immune homeostasis, thereby precipitating a health crisis. These findings advance understanding of temnocephalid-crustacean relationships and highlight risks of symbiont overproliferation in aquaculture systems.

The objective of the present study was to evaluate the effects of gradient addition of Lactobacillus plantarum to feed on growth performance, digestive enzyme activities, antioxidant capacity, immune response, and intestinal health of red claw crayfish. The experiment comprised four distinct treatment groups: control group (CK, 0 gkg(-)(1)), low concentration group (LL, 0.10 gkg(-)(1)), medium concentration group (ML, 1.00 gkg(-)(1)), and high concentration group (HL, 10.00 gkg(-)(1)). Three biological replicates were established in each group, with each replicate containing 50 juvenile crayfish at the beginning of the experiment, with initial body weights ranging from 0.13 +/- 0.01 g. The experiment spanned 70 days. The experimental results showed that different concentrations of Lactobacillus plantarum significantly increased (p < 0.05) the weight gain rate, specific growth rate, length gain rate, hepatosomatic index, survival rate, and intestinal morphology in red claw crayfish. Additionally, the treatment significantly enhanced (p < 0.05) the activities of lipase, tryptase, and alpha-amylase in the intestine and hepatopancreas, and significantly up-regulated (p < 0.05) the expression of key genes in the hepatopancreas related to antioxidant defense, immunity, and stress response, including superoxide dismutase, glutathione peroxidase, glutathione, catalase, anti-lipopolysaccharide factor, crustacean hyperglycemic hormone, serine protease inhibitors, lysozyme, alkaline phosphatase, down syndrome cell adhesion molecule, antibacterial peptides, and heat shock protein 70. In conclusion, the addition of Lactobacillus plantarum to the feed of red claw crayfish significantly enhanced its growth performance, digestive enzyme activities, antioxidant capacity, and immune response capacity and positively affected its intestinal health. The optimum addition of Lactobacillus plantarum under this experiment was determined to be 1.00 gkg(-)(1) .

In aquaculture, the use of probiotics to improve growth, immunity, and stress resistance in crustaceans has gained increasing attention. This study examined the effects of incorporating different levels of Rhodotorula mucilaginosa (0.0, 0.1, 1.0, and 10.0 g/kg) into the diet on growth performance, antioxidant capacity (AOC), immune function, Toll/Imd, and JAK-STAT signaling pathways in red claw crayfish (Cherax quadricanatus). The investigation was conducted through a 56-day feeding trial. The main results are as follows: Compared with the control group (0.0 g/kg), different R. mucilaginosa levels significantly increased (p < 0.05) the specific growth rate (SGR) and weight gain rate (WGR) of red claw crayfish, significantly increased (p < 0.05) the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione S-transferase (GST), total AOC (T-AOC), and acid phosphatase (ACP) in hepatopancreas of red claw crayfish, and significantly upregulated (p < 0.05) the relative expression levels of tumor necrosis factor receptor-associated protein 6, akirin, immunodeficiency homolog, interferon regulatory factor 4, Toll-like receptor (TLR) 6, TLR 2, Janus kinase, signal transducer activator of transcription, tumor necrosis factor α, interleukin-1β, transforming growth factor-β1 genes in the hepatopancreas of red claw crayfish. In conclusion, R. mucilaginosa significantly enhanced red claw crayfish's growth, AOC, and immune function, and activated the Toll/Imd and JAK-STAT signaling pathways. In this experimental context, the ideal addition level of R. mucilaginosa is 1.0 g/kg.

The objective of this study was to evaluate the effects of dietary supplementation with different levels of Rhodotorula mucilaginosa (0.0 g/kg, 0.1 g/kg, 1.0 g/kg, and 10.0 g/kg) on resistance to Aeromonas veronii infection in red claw crayfish (Cherax quadricarinatus) (initial body weight of 0.13 ± 0.06 g). The investigation combined a 56-day feeding trial with a subsequent 7-day infection challenge to assess cumulative mortality, immune and antioxidant enzyme activities, and the relative expression of immune-related genes. During the A. veronii infection test, the cumulative mortalities for the 0.1 g/kg, 1.0 g/kg, and 10.0 g/kg groups were 44.44%, 38.89%, and 38.89%, respectively, all significantly lower (p < 0.05) than that of the control group (58.33%). Compared with the control group, after infection with A. veronii, the activities of acid phosphatase, alkaline phosphatase, catalase, and superoxide dismutase in the hepatopancreas and alkaline phosphatase, lysozyme in the hemolymph of red claw crayfish in the 1.0 g/kg group significantly increased (p < 0.05). The activities of aspartate aminotransferase and alanine aminotransferase in the hemolymph of red claw crayfish in the 1.0 g/kg group significantly decreased (p < 0.05). The relative expression levels of serine protease inhibitor, crustacean hyperglycemic hormone, anti-lipopolysaccharide factor, and superoxide dismutase genes in the hepatopancreas of red claw crayfish in the 1.0 g/kg group were significantly upregulated (p < 0.05). In conclusion, R. mucilaginosa could significantly improve the antibacterial ability of red claw crayfish against A. veronii. In this experimental context, the ideal addition level of R. mucilaginosa is determined to be 1.0 g/kg.

The giant freshwater prawn (GFP; Macrobrachium rosenbergii), a tropical species cultured worldwide, has high market demand and economic value. Male GFP growth varies considerably; however, the mechanisms underlying these growth differences remain unclear. In this study, we collected gut and hemolymphatic samples of large (ML), medium (MM), and small (MS) male GFPs and used the 16S rRNA sequencing and liquid chromatography–mass spectrometry-based metabolomic methods to explore gut microbiota and metabolites associated with GFP growth. The dominant bacteria were Firmicutes and Proteobacteria; higher growth rates correlated with a higher Firmicutes/Bacteroides ratio. Serum metabolite levels significantly differed between the ML and MS groups. We also combined transcriptomics with integrative multiomic techniques to further elucidate systematic molecular mechanisms in the GFPs. The results revealed that Faecalibacterium and Roseburia may improve gut health in GFP through butyrate release, affecting physiological homeostasis and leading to metabolic variations related to GFP growth differences. Notably, our results provide novel, fundamental insights into the molecular networks connecting various genes, metabolites, microbes, and phenotypes in GFPs, facilitating the elucidation of differential growth mechanisms in GFPs.

The growth environment significantly influences the intestinal microbiota of aquatic organisms. We investigated the composition and functional differences in the intestinal microbiota of red claw crayfish (Cherax quadricarinatus) in rice fields (RB) and ponds (PB) by 16S rDNA high-throughput sequencing technology. The results indicate that the Shannon, Simpson, Sobs, Chao1, and ACE indices of PB are all higher than those of RB, demonstrating greater diversity and richness of intestinal microbiota. The dominant phyla in the intestinal microbiota of the Cherax quadricarinatus were Proteobacteria, Tenericutes, and Firmicutes. Tenericutes and Proteobacteria were significantly more abundant in the RB than in the PB, while Planctomycetes and Firmicutes were significantly more abundant in the PB than in the RB. The results of network correlation analysis indicate that Proteobacteria and Firmicutes exhibit strong connectivity with other microbial groups in the gut microbiota of Cherax quadricarinatus, showing significant centrality. They play an important role in the interactions within the gut microbiota community. The dominant bacterial genera in the Cherax quadricarinatus’s gut were Citrobacter, Candidatus_Bacilloplasma, and Clostridium_sensu_stricto_1. The abundance of the genus Clostridium was significantly higher in the PB than in the RB, whereas the abundance of Candidatus_Hepatoplasma and Vibrio was significantly lower in the PB than in the RB. The prediction function of KEGG enrichment showed that the abundance of Amino acid metabolism, Biosynthesis of Other Secondary Metabolites, Transport and Catabolism, Cancers, and Nervous System, Substance Dependence were significantly higher in the PB, while the infectious diseases pathway was enriched in the RB. In summary, our results revealed significant differences in the composition and diversity of intestinal microbiota in the Cherax quadricarinatus between rice paddy and pond farming environments. The intestinal microbiota of the Cherax quadricarinatus grown in pond environments exhibit higher diversity and stability, manifested by an increase in beneficial bacteria abundance and a decrease in opportunistic pathogens. These findings significantly improve understanding of the complex relationship among Cherax quadricarinatus, intestinal microbiota, and the environment.

The giant freshwater prawn (Macrobrachium rosenbergii), which is widely distributed in Southeast Asia and the western Pacific, is an important commercial prawn species. However, the molecular mechanism of ovarian development is unclear, and there were available data on the ovarian transcriptome of M. rosenbergii is limited. In this study, we constructed transcriptomes of female (ZW) and super female (WW) of M. rosenbergii ovaries to discover genes and pathways related to ovarian development. 71,555 unigenes were obtained, with an average length of 1,530 bp and N50 of 3001 bp. 15,792 (29.3%) unigenes were annotated. A total of 13,610 differentially expressed genes (DEGs) were detected. KEGG pathway analysis showed that multiple pathways related to ovarian development were significantly regulated, such as retinol metabolism, notch signalling pathway, cell cycle, wnt signalling pathway, FoxO signalling pathway, and mTOR signalling pathway. In addition, 12 putative ovarian development-related genes, including FZD9, DDR2, PSMC3IP, CREBBP, DMC1, WBP2NL, DHRS4, SPO11, BCDO2, SDR16C5, CPEB, RDH5, were identified. Our findings will provide a valuable archive for future functional analysis of genes related to ovarian development and future discoveries of the underlying molecular mechanisms of ovarian development.

为了解稻田养殖红螯螯虾(Cherax quadricarinatus)个体大小与肠道菌群的相关性,实验采用16S rDNA高通量测序和生物信息学技术对稻田养殖红螯螯虾大个体(RB)组和小个体(RS)组肠道菌群的组成、多样性、指示物种、功能等进行比较分析.结果显示:RB组共产生615个OTUs(Operational taxonomic units),RS组共产生602个OTUs,共有OTUs为345个,特有OTUs分别为270个和257个.RB组和RS组的优势菌群相似,门水平主要为变形菌门(Proteobacteria)、软壁菌门(Tenericutes)、厚壁菌门(Firmicutes)等,属水平主要为Candidatus Bacillo-plasma、柠檬酸杆菌属(Citrobacter)、梭菌属(Clostridium)等,但菌群组成存在差异.另外,RB组和RS组的指示物种和菌群代谢功能也存在差异.结果表明稻田养殖红螯螯虾个体大小与肠道菌群组成及其代谢功能有关,在相同的养殖环境和饲养方法条件下,肠道微生物可作为内在因素影响红螯螯虾的生长性能.

Red claw crayfish (Cherax quadricarinatus) has recently attracted widespread attention as an emerging candidate for sustainable aquaculture production in Australia and abroad. Although they are of great economic importance, few full-length transcriptomes are available. Here, transcripts of C. quadricarinatus were generated by using Pacific Biosciences single-molecule real-time (SMRT) long-read sequencing technology. With SMRT, 289,232 full-length nonchimeric reads were identified, resulting in 14,089 unigene, with an N50 length of 4363 bp and a mean read length of 3913 bp. The error rate of SMRT sequences by comparison with Illumina-produced short reads was only 0.011%. A total of 13,449 transcripts (95.4%) were annotated against the protein database. Across all transcripts, 4952 long noncoding RNAs (lncRNAs), 1090 putative TF members and 21,108 simple sequence repeats (SSRs) were identified. After Vibrio alginolyticus infection, a total of 252 DEGs were screened out after a comparative analysis between samples. Of the 252 DEGs, Hsps, IAPs and Gpx were upregulated during V. alginolyticus infection, many genes were associated with V. cholerae infection, the NF-kappa B signalling pathway, apoptosis-multiple species, the TNF signalling pathway and antigen processing and presentation pathways. Our study provides a rich set of full-length cDNA sequences for C. quadricarinatus, which will greatly facilitate crayfish transcriptome research.

[目的]探讨池塘养殖红螯螯虾(Cherax quadricarinatus)个体大小与其肠道细菌间的关系,为筛选虾类肠道有益菌提供参考依据.[方法]提取池塘养殖红螯螯虾后肠样品的总DNA,采用16S rDNA高通量测序技术对其大个体组(PB组)和小个体组(PS组)肠道微生物进行测序,并进行生物信息学分析.[结果]在红螯螯虾后肠样品中,PB组共检出1211个分类操作单元(OTU),PS组共检出587个OTUs,其中365个OTUs为PB组和PS组肠道微生物共有.Alpha多样性分析结果显示,PB组红螯螯虾肠道微生物多样性的Chao1指数、Ace指数和Shannon指数均极显著高于PS组红螯螯虾(P＜0.01).PB和PS组红螯螯虾肠道微生物排名前十位的优势菌群在门、目和属水平上均相似,但菌群组成和指示物种存在差异,其中,在门水平上,PB组的优势菌门为厚壁菌门,占比42.87％,而PS组的优势菌门为变形菌门,占比59.77％;在目水平上,PB组的优势菌目为梭菌目,占比41.25％,而PS组的优势菌目为肠杆菌目,占比57.01％;在属水平上,PB组的优势菌属为梭菌属,占比30.83％,而PS组的优势菌属为柠檬酸杆菌属,占比36.07％;PB组的指示物种是厚壁菌门和浮霉菌门,而PS组的指示物种是变形菌门.此外,PB组和PS组的菌群代谢功能也存在差异,PB组除影响因子和聚糖生物合成与代谢的丰度显著低于于PS组外(P＜O.05,下同),其他代谢(氨基酸代谢、外源生物降解与代谢及萜类化合物和聚酮类化合物代谢等)的丰度均显著高于PS组.[结论]与小个体红螯螯虾相比,大个体红螯螯虾肠道微生物的组成和丰度及其代谢功能明显占优.因此,在相同的养殖环境和饲养方法下,红螯螯虾肠道微生物组成和丰度及其代谢功能是影响红螯螯虾生长性能的内在因素之一.

Gonadotropin releasing hormone (GnRH) plays an important role in the regulation of vertebrate reproduction. Studies have shown that immunization against GnRHa can induce sexually sterile tilapia. To explore the mechanism behind this, in this study, RNA-seq and data-independent acquisition (DIA) techniques were used to study the transcriptome and proteome of the gonad of tilapia immunized with GnRHa. 644 differentially expressed genes (80 upregulated and 564 downregulated) and 1150 differentially expressed proteins (351 upregulated and 799 downregulated) were identified. There were 209 genes with consistent differential expression patterns in the transcriptomic and proteomic analyses, of which 9 were upregulated and 200 downregulated, indicating that the gonad gene expression was inhibited by GnRHa immunization. The downregulated genes were particularly involved in the functions of single-organism process, binding, cellular process, metabolic process and catalytic activity, and associated with the pathways including ECM-receptor interaction, focal adhesion, cardiac muscle contraction and oxidative phosphorylation. The expression of six differentially expressed genes involved in the GnRH signaling pathway was all downregulated. In addition, several important functional genes related to gonadal development after GnRHa immunization were screened. This study confirmed the expression of corresponding genes was affected by GnRHa on the gonad development in tilapia at the molecular level, and laid a foundation for elucidating the mechanism of GnRHa immunization.

[目的]原核表达红螯螯虾(Cherax quadricarinatus)卵黄蛋白原(Vg)VWD结构域,为深入开展Vg的生物学功能研究和开发相应的生物活性物质提供技术支持,也为改进虾类养殖催熟及获取高质量后代打下基础.[方法]在GenBank中搜索红螯螯虾卵Vg的mRNA序列(AF306784.1)及查找其VWD结构域(2345～2491 aa),采用ExPASy ProtParam、ProtScale、InterProscan及TMHMM等在线软件进行生物信息学分析及理论评估,结合大肠杆菌密码子偏好优化原始VWD氨基酸序列;然后通过全基因合成获得目的基因,连接至载体pET-28a构建重组质粒pET-28a-VWD,挑取阳性克隆转化大肠杆菌BL21(λDE3)感受态细胞及采用IPTG进行诱导表达,并以10％SDS-PAGE电泳和Wes-tern blotting检测诱导表达的融合蛋白.[结果]红螯螯虾VWD结构域相对分子量为19692.11 Da,理论等电点(pI)为9.35,分子式为C855H1334N258O261S9,属于不稳定的亲水性蛋白,不含跨膜结构域.延伸链和无规则卷曲是红螯螯虾VWD结构域二级结构的主要元件,其中,α-螺旋占7.73％,β-转角占10.50％,延伸链占35.91％,无规则卷曲占45.86％.重组质粒pET-28a-VWD经大肠杆菌BL21(λDE3)感受态细胞诱导表达即获得融合蛋白VWD,以2 mol/L盐酸胍溶解和Ni-NTA亲和层析纯化及复性后,10％SDS-PAGE电泳和Western blotting检测均在蛋白相对分子量约20.0 kD处出现1条清晰的特异性条带,融合蛋白VWD表达形式以包涵体为主.融合蛋白VWD在BL21(λDE3)感受态细胞中高效表达的最佳诱导条件:当单克隆菌液OD600 nm达0.6时添加0.5 mmol/L IPTG,置于20℃下诱导培养16 h.纯化后的融合蛋白VWD浓度为1.32 mg/mL.[结论]通过全基因合成获得的优化红螯螯虾VWD基因能在大肠杆菌BL21(λDE3)感受态细胞中诱导表达出以包涵体为主要形式的融合蛋白,经盐酸胍溶解和Ni-NTA亲和层析柱纯化及复性即可获得高纯度的活性VWD蛋白,为后续开展红螯螯虾Vg生物学功能研究及开发相应的生物活性物质提供技术支持.

【目的】建立XX型全雌吉富罗非鱼家系,为今后进行全雄吉富罗非鱼规模化制种提供优质母本,进而为罗非鱼性别控制及育种研究提供基础材料。【方法】通过给仔鱼连续15 d投喂60 mg/kg的甲基睾丸酮（MT）诱导获得表型全雄吉富罗非鱼,经测交筛选获得伪雄吉富罗非鱼（♂:XX）,与常规雌性吉富罗非鱼（♀:XX）交配繁育全雌罗非鱼家系,经过3个世代选育获得全雌和伪雄吉富罗非鱼。根据吉富罗非鱼生殖孔外观结构差异进行性别鉴定;测量150日龄时各吉富罗非鱼家系的体长和体重,并计算罗非鱼肥满度。【结果】MT诱导吉富罗非鱼的雄性率达100.0%;吉富罗非鱼选育家系F 1 ～F 3 代的平均雌性率分别为80.3%、92.4%和99.9%,分别获得5、5和6个全雌家系,其中F 3 代仅有1个非全雌家系（雌性率为99.4%）。吉富罗非鱼选育家系F 1 ～F 3 代150日龄雄性罗非鱼的平均体重分别为815.4、857.9和930.1 g,较对照组提高8.73%、14.62%和21.31%,其中F 2 和F 3 代的体重显著高于对照组（P＜0.05,下同）;3个世代雄性罗非鱼平均体长分别为25.63、25.48和26.22 cm,较对照组提高3.51%、2.87%和4.42%,F 3 代的体长显著高于对照组。吉富罗非鱼选育家系F 1 ～F 3 代150日龄雌性罗非鱼的平均体重分别为733.9、745.0和789.8 g,较对照组显著提高12.13%、16.48%和24.99%;平均体长分别为24.57、24.35和24.79 cm,较对照组提高3.93%、3.13%和4.07%,其中F 1 代的体长显著高于对照组。经过3个世代选育,吉富罗非鱼的生长性能得到大幅提升,F 3 代吉富罗非鱼选育家系的平均体重提高22.97%,保种家系的平均体重提高28.62%,且肥满度也得到明显提高。【结论】通过MT诱导处理可批量生产伪雄吉富罗非鱼,实现全雌吉富罗非鱼的规模化制种,经过3个世代选育,获得的伪雄和全雌吉富罗非鱼生长性能显著提高,更适于吉富罗非鱼育种及性别相关研究。

Our previous study showed that human-derived Streptococcus agalactiae (serotype V) could infect tilapia, but the mechanism underlying the cross-species infection remains unrecognized. In this study, a multi-omics analysis was performed on human-derived S.agalactiae strain NNA048 (virulent to tilapia, serotype V, ST1) and human-derived S.agalactiae strain NNA038 (non-virulent to tilapia, serotype V, ST1). The results showed that 907 genes (504 up/403 down) and 89 proteins (51 up/38 down) were differentially expressed (p < 0.05) between NNA038 and NNA048. Among them, 56 genes (proteins) were altered with similar trends at both mRNA and protein levels. Functional annotation of them showed that the main differences were enriched in the arginine deiminase system signaling pathway and biotin metabolism signaling pathway: gdhA, glnA, ASL, ADI, OTC, arcC, FabF, FabG, FabZ, BioB and BirA genes may have been important factors leading to the pathogenicity differences between NNA038 and NNA048. We aimed to provide a comprehensive analysis of the human-derived serotype V ST1 S.agalactiae strains, which were virulent and non-virulent to tilapia, and provide a more comprehensive understanding of the virulence mechanism.