The body color of juvenile Chinese giant salamander (Andrias davidianus) exhibits a lighter hue in a dimly lit environments and a darker hue in well-lit environments, and this variation follows a circadian rhythm. To determine the effect of light on the body color of juvenile salamanders, three treatments were arranged in this study, including: natural light (C, control light, 12 h day/night), high light (H, 24 h day, 220 Lux), and complete darkness (B, 24 h night, 0 Lux). Skin samples were collected for RNA sequencing after 12 days, and skin, blood, liver, brain, and eyes were gathered on days 0, 4, 8, and 12 for skin density measurement, tissue sectioning, enzyme activity detection, and qPCR validation to analyze the effect of light on the characterization and molecular regulation of the body color. The results showed that with constant lighting, the skin color significantly darker, exhibiting the lowest average gray level and highest average optical density. HE staining showed a significant increase and clustering of melanin particles between the epidermis and glands. The activity of tyrosinase in the skin was highest on the days 8 in group H. Both continuous light and darkness significantly increased the activity of CAT in the liver and serum. qPCR validation showed that key genes involved in various melanin biosynthesis pathways (such as Tyr, Tyrp1, Pmel) were generally upregulated in the group H. In summary, light can activate the pigment synthesis pathway, promote melanin deposition and gene expression, and enhance antioxidant enzyme activity. However, continuous exposure to light and darkness can disrupt the circadian rhythm in the giant salamander, inducing feedback changes in certain genes. The giant salamander adapts to its environment by coordinating melanin deposition and antioxidant defense, achieving dynamic changes in body color while clearing free radicals to mitigate oxidative damage.

Cyprinus carpio var. Xiangxi is a regionally farmed rice-field carp endemic to the Xiangxi region of Hunan Province, China. To adapt to the rice-fish farming environment, this variety has developed a range of genetic and physiological adaptations. However, genomic research on this strain remains limited. Here, we assembled a high-quality chromosome-level genome of C. carpio var. Xiangxi to fill this knowledge gap. Using PacBio HiFi, DNBSEQ, and Hi-C technology, We generated a 1.54 Gb genome with a contig N50 of 28.12 Mb. Using Hi-C data, 99.38% of the assembly (1,535.34 Mb) was anchored to 50 pseudochromosomes, yielding a scaffold N50 of 30.26 Mb. The quality value and Benchmarking Universal Single-Copy Ortholog score were 62.32 and 97.4%, respectively, indicating that our genome sequence is of high quality and completeness. A total of 46,362 protein-coding genes were predicted, of which 45,409 (97.94%) were functionally annotated. This study provides a valuable genomic resource for the conservation of C. carpio var. Xiangxi and offers new insights into the evolutionary history of common carp.

The Chinese soft-shelled turtle (Pelodiscus sinensis) is an important aquaculture animal in China and exhibits growth dimorphism. Single-male cultures are often selected for higher economic efficiency. However, the mechanism of sex differentiation in P. sinensis is not well-known. In this study, a comparative transcriptome analysis of male (ZZ)- and 17β-oestradiol (E2)-induced pseudo-female (ZZ + E2)-stage embryonic gonads of P. sinensis was performed. A total of 420 differentially expressed genes (DEGs), which included 271 upregulated genes and 149 downregulated genes, were identified. These DEGs were mainly involved in several sex-related pathways, such as “ovarian steroidogenesis”, “steroid hormone biosynthesis”, “PPAR signalling pathway”, and “metabolism of xenobiotics by cytochrome P450”. In addition, 50 known and novel candidate genes involved in sex differentiation, such as the male-biased genes AMH, DMRT1, TBX1, and CYP26A1 and the female-biased genes CYP1A1, RASD1, and SOX17, were investigated and identified. For further verification, the full-length cDNAs of SOX17 and CYP26A1 were obtained. SOX17 contains a 1218-bp ORF and encodes 405 amino acids containing an HMG functional domain unique to the Sox superfamily. CYP26A1 contains a 1485-bp ORF and encodes 494 amino acids. Different expression levels of SOX17 and CYP26A1 could be detected in all the tested tissues of males and females. Notably, the expression of CYP26A1 was markedly greater in the gonads of male embryos (P < 0.05) than in those of female embryos, whereas the expression of SOX17 showed the opposite trend (P < 0.05). Taken together, the RNA-seq and qRT‒PCR results suggested potential roles for SOX17 and CYP26A1 in promoting female and male gonadal development, respectively, in P. sinensis. Our results provide new evidence for the mechanism of sex differentiation in P. sinensis.

Background TRIM proteins, recognized as a class of E3 ubiquitin ligases, are increasingly acknowledged for their antipathogen immune functions in mammals and fish. In the Chinese soft-shelled turtle ( Pelodiscus sinensis ), a secondary aquatic reptile that occupies a unique evolutionary position, the TRIM gene has rarely been reported. Methods and results In the present study, 48 Ps TRIM proteins were identified from the genome of Pelodiscus sinensis via Hidden Markov Model (HMM) searches and Signal Transduction ATPases with Numerous Domains (SMART) analysis. These Ps TRIMs were found across 43 distinct scaffolds, and phylogenetic analyses classified them into three principal clades. The Ps TRIMs feature a conserved assembly of either RING-B-box-coiled-coil (RBCC) or B-box-coiled-coil (BBC) domains at the N-terminus, in addition to eight unique domains at the C-terminus, including the B30.2 domain, 19 of which were identified. Expression profiling revealed ubiquitous expression of the 48 Ps TRIMs across various P. sinensis tissues. Notably, seven Ps TRIMs exhibited significant differential expression in liver transcriptomes following infection with Aeromonas hydrophila . Weighted gene coexpression network analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis implicated Ps TRIM14 and Ps TRIM28 as key players in host defense against bacterial invasion. Real-time quantitative PCR results indicated that Ps TRIM1, Ps TRIM2, Ps TRIM14, and Ps TRIM28 experienced marked upregulation in P. sinensis livers at 12 h post-infection with A. hydrophila . Conclusions Our study is the first to comprehensively identify and analyze the functions of TRIM genes in P. sinensis , unveiling their considerable diversity and potential roles in modulating immune responses.

Tapeworms are infamous and highly successful invasive parasites in aquatic animals, especially in fish. However, tapeworm-caused diseases in soft-shelled turtles are rarely discovered. In this study, a case of cultured Chinese soft-shelled turtle (Pelodiscus sinensis) infected with tapeworm in Changde city of China was reported, and the taxonomic identification of the tapeworm and the effects of tapeworm on the Chinese soft-shelled turtle were revealed. The 28S rRNA sequences of the tapeworm from P. sinensis had the highest similarity (99.82%) with Testudotaenia testudo of Proteocephalidea (Eucestoda), suggesting they are identical species. Infected turtles showed typical clinical symptoms of cestodiasis, which included nutrition loss, and histopathological lesions in the liver and intestine. The serum of infected turtles had significantly lower (P < 0.05) concentrations of glucose, creatinine, total protein, and low-density lipoprotein, and significantly higher (P < 0.05) alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), superoxide dismutase (SOD) activities. Trancriptional analyses showed that 158 differentially expressed genes (DEGs) were found in liver of infected turtles compared with uninfected groups. These DEGs mainly involved in metabolism, including "Arachidonic acid metabolism", "Linoleic acid metabolism", "Metabolism of xenobiotics by cytochrome P450", "alpha-Linolenic acid metabolism", "Ether lipid metabolism", "Retinol metabolism" and "Glycerophospholipid metabolism", which suggested that the tapeworm infection seriously affected the nutrient metabolism of P. sinensis. Besides, 12 immune-related DEGs were discovered and 7 of them were down-regulated, which inferred that tapeworm may regulate immune responses of host. Gut microflora analysis showed that there were no significant differences in richness and diversity between the infected and uninfected groups. Nevertheless, some opportunistic pathogens such as Citrobacter, Edwardsiella, and Lawsonia were significant higher (P < 0.05) in infected turtles, and the intestinal microflora in infected turtles were associated with "Bacterial invasion of epithelial cells" based on functional prediction. Overall, our results suggested that the tapeworm infection caused mechanical damage in the intestine, metabolism disorder in liver, and increased abundance of pathogenic bacteria in gut microflora. Our results provided a first insight into the pathogenesis of tapeworm infection in the Chinese soft-shelled turtle.

1试验材料与方法 1.1稻田选择 稻田选择在花垣县麻栗场镇沙科,稻鱼综合种养"一二三"养殖模式,稻田12丘,共3,936m2;传统稻鱼综合种养模式稻田12丘,共3,896m2;试验选择稻田交通便利,田埂坚实,水源排灌方便. 1.2田间工程建设 2022年5月初,对稻田田埂进行修整,加宽加固田埂,使田埂高出稻田平面50cm左右,夯实田埂,确保田埂不塌陷.

湘西地处武陵山片区,有耕地面积1,360km2,其中可宜渔稻田966km2,稻鱼综合种养产业发展潜力巨大.近年来,湘西州在境内推广稻鱼综合种养产业,取得了较好的成效.为了探索最优的"稻花鱼"苗种投放密度,本试验对种植"和两优晶丝"的稻田投放不同数量的100g/尾规格的鲤鱼进行稻鱼综合种养试验,以为湘西州稻鱼综合种养产业发展提供指导.

中华鳖(Pelodiscus sinensis)是我国名特优水产养殖品种,在我国大部分地区均有分布.其肉质鲜美,蛋白质含量高,裙边粗蛋白含量为 20％～24％,是典型的低脂高蛋白食品,深受消费者的青睐[1].此外中华鳖还是滋补药膳的佳品,其背甲、肉、血、卵、肝、胆等均可入药,对潮热盗汗、阴虚阳亢等病症具有良好的功效[2].目前,我国中华鳖养殖已经具有较大的产业规模,根据《2022 中国渔业统计年鉴》[3], 2021 年全国鳖的养殖产量为 36.48 万t,主要养殖品种为中华鳖,其中湖南 3.8 万t,占全国鳖总产量的10.64％.随着人民生活水平的提高,农业-水产复合体系是农业发展的主要方向[4],藕鳖混养是新型农业-水产复合模式之一[5].现于 2022 年 4 月26 日—11 月 5日在藕塘进行鳖鱼混养试验.

湘西呆鲤(以下简称"呆鲤")是湘西地方特有的鲤鱼品种,其肉质细腻,营养丰富,深受当地老百姓的喜爱.湖南丘陵地貌居多,丘陵地区以"稻-鲤""稻-鲤-禽"模式为主,湖区周边以"稻-虾""稻-鳖"多见.湘西土家族苗族自治州养殖呆鲤虽久,但养殖技术较为落后,规模化养殖较少,现一般为稻田散养,亩产量不高,生产效益不明显.当地山泉水资源丰富,多为落差较高的梯田,土质疏松,储水能力较差.特殊的地理条件和落后的养殖模式导致呆鲤亩产量较低,本文提出"稻-呆鲤"的三种养殖技术模式(开挖一字形、十字形、井字形鱼沟),养殖150天并量化各项生长数据,以期为农民增产增收提供参考.

本研究旨在研究复合益生菌对幼鲵生长及免疫指标的影响.随机选取体质健康、体重100g/尾左右的2龄幼鲵,分别添加占基础饵料重量0.20％、0.40％、0.60％的配比复合益生菌进行拌料投喂试验,并设置空白对照组,每组设置三个重复组,共12组,试验期180d.试验结束时测定各组大鲵的生长及摄食指标、血液生理生化指标及血清抗氧化酶及非特异性免疫指标,结果显示三个试验组大鲵终末体重、平均增重率、特定生长率均显著高于对照组,指标数据说明以复合益生菌拌料投喂有利于大鲵的生长;中剂量组及高剂量组大鲵血液中的总蛋白(TP)及白蛋白(ALB)含量均显著高于对照组及低剂量组;试验组大鲵血清中酸性磷酸酶(ACP)均高于对照组,这显示出复合益生菌拌料投喂对大鲵的非特异性免疫有促进作用;中剂量组及高剂量组大鲵血清中超氧化物歧化酶(SOD)活性均显著性高于对照组及低剂量组.结果表明,复合益生菌(芽孢杆菌、酵母菌、乳酸菌)添加日常饵料重量0.40％、0.60％的配比中剂量、高剂量组不仅能促进大鲵的生长发育,同时还能促进大鲵对营养物质的吸收利用,从而增强体质,提升疾病抵抗力.

花垣县位于湘西自治州西北部,地处云贵高原东部边缘,为亚热带季风山地湿润气候区,春季气温回暖较早,但不稳定,夏季降雨较多,而冬季寒冷而且湿度较大,全年无霜期280d左右.近年来,全县大力推广稻田生态养鱼技术,2020年全县发展稻田生态养鱼2.19万亩,年产"稻花鱼"762t,"稻花鱼"鲜鱼年产经济效益过千万,稻花鱼"产业在促进农业产业发展中起着重要的作用为此,本文对本县"稻花鱼"养殖管理技术进行总结,以为养殖户提供参考.

The Chinese soft-shelled turtle ( Pelodiscus sinensis ) is an economically important and rare freshwater aquaculture species in China. The male turtles have better economic benefits than females due to their faster growth speed. In order to explore the mechanism of sex differentiation and determination of P. sinensis , transcriptome analysis was carried out using embryo samples from the sex determination, sex differentiation and shelling stages, respectively. The gender types of embryos were identified by genotyping and histological analysis. In all, 277,230 and 273,859 genes were identified from embryos of male and female turtles, respectively. Cluster analysis of gene expression patterns exhibited trends for all differentially expressed genes (DEGs), which can be classified into three subclusters. In the sex determination, sex differentiation, and shelling stages 975, 43, and 300 DEGs, respectively, were identified by comparing the male and female groups. KEGG analysis was used to explore the function of the DEGs. Fgf9 , foxl2 , mex3 b, sox7 , tgfβ -3, wnt4 , wnt7a , and wt1 were upregulated in ovary development stages and chfr , ampk , aldh2 , dao , glt1d1 , hvcn1 , psmd9 , srsf9 and ubc were upregulated in testis development stages, indicating that these genes play important roles in the sex development of P. sinensis . The results of this study provide preliminary insights into the sex determination and differentiation of Chinese soft-shelled turtles.

湘西地区包括湘西自治州、怀化市、张家界市、邵阳西部的部分县(市)及永州市的江华瑶族自治县,地处湖南省西部,境内绝大多数县(市)属边远山区,草鱼苗种多为外购,由于运输成本高,成活率低等原因,草鱼的养殖量小.为解决草鱼苗种的供应问题,在属于湘西地区的怀化市辰溪县安坪镇曾家坪村山塘,对购买的草鱼"夏花"苗种进行了培育试验.

近年来,湘西州稻田生态养鱼发展速度较快,湘西自治州境内各县市稻田养鱼各有特色,其中花垣县以"紫米"水稻+"稻花鱼"的模式取得了良好的经济效益,通过紫米加工,延伸了湘西州稻田综合种养产业链,促进了当地乡村振兴.于2020年4月28日,在湘西州龙潭镇开展了福田生态养鱼试验.

为探究湘西呆鲤(Cyprinius carpio var.Xiangxi)形态性状与体质量的关系,随机测量107尾湘西呆鲤的全长(X1)、体长(X2)、体高(X3)、体厚(X4)、躯干长(X5)、头宽(X6)、头长(X7)、吻长(X8)、眼径(X9)、眼后头长(X10)、尾柄长(X11)、尾柄高(X12)、眼间距(X13)、侧线鳞(X14)、侧线上鳞(X15)、侧线下鳞(X16)等16项形态性状指标和体质量(Y).采用相关性分析、通径分析、多元回归分析及曲线拟合等方法,评价湘西呆鲤的形态性状对其体质量的影响程度.结果显示,湘西呆鲤16项形态性状中,有14项与体质量表现出极显著相关性,其中相关性较高的性状为体高(X3)＞全长(X1)＞体长(X2)＞体厚(X4)＞尾柄高(X12);体高(X3)对体质量的直接作用最大(0.433),且全长(X1)、尾柄长(X11)、尾柄高(X12)等性状均通过体高(X3)对体质量(Y)的间接作用最大,按决策作用大小,体高(X3)的决策系数最大,R2(X3)=0.651;引入多元回归分析,构建出主要形态性状与体质量(Y)的多元回归方程:Y=-73.175+3.239X1+1.368X3+0.168X11+1.118X12;进一步对方程中各形态性状与体质量进行曲线拟合,体高(X3)的拟合优度最高,为0.964,曲线拟合方程:Y=0.002X32.72.综上分析,湘西呆鲤体高是影响其体质量的主要关键性状,可作为后期湘西呆鲤体质量选育改良的重要辅助性状.

为获得中华鳖(Trionyx sinensis)性别差异表达基因,探索中华鳖性别决定机制,本研究采用RNA-Seq技术测定了中华鳖成熟期精巢和卵巢转录组,分别获得了21494396400 bp和24605142600 bp的clean data.获得总的差异基因10145个,其中在卵巢中表达上调的有4034个,在卵巢中表达下调的有6111个.通过GO、KEGG及蛋白互作分析,在中华鳖性别差异的研究中,获得117个性别表达差异的基因,在雌性中高表达的性别相关基因有Foxl2、Sox3、Sox7、Bmp4、Csf 1、Wnk2、Mtmr4、Gsc、Mr2 f 2、Fgf 9、Tgfβ2、Tgfβ3、Rara、Smd2、Smd3和Smad5等;在雄性中高表达性别相关基因有Dmrt1、Amh、Sox30、Cct4、Cct5、Cldn11、Crem、Dhcr24、Dnai2、Dynll1、Gabarap、Herc4、Her-pud2、Hexb、Hook1、Hormad1和Smc4等;同时Bmp4通过Smad信号通路调控Foxl2的表达,Foxl2基因为中华鳖雌性生理性别的标志基因.

为了揭示湘西呆鲤的进化地位,通过二代基因测序技术获得湘西呆鲤(Cyprinus carpio var.Xiangxi)线粒体基因组全序列,对线粒体基因进行了注释,对其序列结构进行了分析,并分别以线粒体全长基因组序列和D-loop区序列对湘西呆鲤在内的16种鲤鱼的同源性进行了分析,采用NJ(Neighbor-joining)法构建16种鲤鱼D-loop区的系统进化树.结果表明:湘西呆鲤线粒体基因组全长16581 bp,编码13个蛋白质,还包含22个tRNA、2个rRNA和1个D-Loop区;碱基组成存在明显的AT偏向和弱AT负偏斜现象;其tRNA均能形成典型的三叶草结构,其中"环"结构长度为7～16 bp,"茎"结构长度为3～7 bp;基于线粒体全长基因组的同源性分析发现16种鲤鱼之间的同源性在89.4％～99.8％之间,而基于D-loop区的同源性在87.3％～98.8％之间,二者存在一定差异;系统进化树结果显示,湘西呆鲤与Labeo catla均独立于各簇,湘西呆鲤与锦鲤和三倍体鲤一簇更为邻近.

为了探究中华鳖(Pelodiscus sinensis)的主要组织相容性复合体(major histocompatibilitycomplex,MHC)的结构和功能,本研究利用RACE技术成功克隆获得中华鳖MHCⅡα基因的cDNA全长序列,其长度为1296 bp,开放阅读框(ORF)为807 bp,共编码268个氨基酸,分为信号肽序列、Ⅱ类组织相容性抗原α结构域、IGc1结构域及跨膜结构域4个功能结构域.通过NJ法构建的系统进化树分析显示,中华鳖与西部锦龟(Chrysemys picta bellii)亲缘较近,而与哺乳类、鸟类及鱼类亲缘关系较远.荧光定量PCR结果显示,MHCⅡαmRNA在中华鳖8个组织中均有表达,在脾、心、肝及肠组织中表达水平较高,在肌肉组织中表达量最低.感染嗜水气单胞菌(Aeromonas hydrophila)12 h后,中华鳖MHCⅡαmRNA在肝和肠组织中的表达显著上调;感染1 d时,在脾组织中的表达显著上调;感染1 d及5 d时,在肾组织中的表达显著上调.研究表明,中华鳖MHCⅡα基因参与了中华鳖免疫反应.

湘西州全州宜渔稻田70余万亩,稻田生态养鱼始于唐代,距今己有1 200多年的历史.湘西州是湖南省扶贫攻坚主战场,随着扶贫工作的深入推进,稻田养鱼因其投入少、周期短、见效快、易操作等特点成为渔业产业扶贫的不二选择.同时稻田生态种养产品因其高品质、生态环保而倍受人们青睐,在生态环保越来越被重视的当下,发展稻田生态渔业己然成为产业发展的新趋势.

湘西呆鲤具有头尖体短、金鳞赤尾等标志型特征.湘西呆鲤作为湘西地区特有的"稻花鱼"养殖品种,因不易逃跑,能降低养殖户的防逃成本,进行推广养殖的基础好.2017年以来,湘西州稻田养鱼面积稳定在7万亩以上,但是全州仅有3家鱼苗鱼种场,而且水平不一,苗种供应能力不足,大多"稻花鱼"苗种通过外购解决,运输成本高,成活率也受到影响.为解决当地苗种供应不足等问题,湘西州畜牧水产中心水产研究团队对湘西呆鲤的稻田繁殖模式进行研究.