The Taiwanese loach (Paramisgurnus dabryanus ssp. Taiwanese), known for its nutritional and ornamental qualities, exhibits a rare form of albinism. Specifically, certain individuals display golden-pink eyes and a golden-red body color devoid of blotches, thereby attracting consumers. However, the principal genes regulating this phenotype remain unidentified. Consequently, this study conducted a transcriptome comparative analysis of the skin between wild-type (M) and mutant (N) Taiwanese loaches. A total of 6,152 differentially expressed genes (DEGs) were identified, comprising 2,467 down-regulated and 3,685 up-regulated DEGs in mutant individuals. Additionally, several pigmentation-related genes (mitf, wnt3, mc1r, wnt1, dct, tyrp1, and tyr) were identified. KEGG enrichment analysis of DEGs revealed pathways associated with melanin deposition, including the melanogenesis, tyrosine metabolism, and folate biosynthesis pathways. Eleven DEGs were randomly selected to validate RNA-seq results through qPCR. Furthermore, key genes (tyr, mc1r) were validated through gene knockout, accurately identifying the main gene responsible for color mutation in the Taiwanese loach. This study not only offers new insights into the molecular mechanism underlying abnormal body color in the Taiwanese loach but also demonstrates that gene knockout technology can rapidly produce a large quantity of golden-red loaches, significantly enhancing their economic value.

The blood parrot cichlid (Cichlasoma citrinellum × C. synspilum), a hybrid of two distinct cichlid fish, is a popular ornamental fish. Its red appearance, achieved through its initial black coloration fading three weeks after hatching, is a key factor in its appeal. However, some juveniles retain their black or mottled skin. Despite its popularity, the molecular mechanisms underlying these color variations remain unclear. In this study, we compared the transcriptome profiles of fading and non-fading skin, identifying 167 differentially expressed genes. Non-fading (black) fish showed 88 up-regulated genes and 79 down-regulated genes compared to those in fading (white) fish. qPCR validated a subset of these RNA-Seq results. The enrichment analysis showed that these genes are associated with melanin production, the cAMP signaling pathway, and fatty acid metabolism. Genes related to eumelanin synthesis were up-regulated, while another synthesis pathway was down-regulated. Genes in the SLC and PDE families, linked to pheomelanin synthesis, were also up-regulated. Our findings suggest that the MSH-MC1R signaling pathway, the SCF/c-kit-Ras pathway, and the pheomelanin synthesis pathway play crucial roles in determining the development of black skin. These conclusions provide a theoretical framework for further research into pigment deposition and breeding albino varieties.

Background/Objectives: Aeromonas veronii is a significant pathogen affecting aquatic animals and has the potential to infect humans. Vaccination remains the most effective strategy for preventing infections caused by this bacterial strain. Methods: This study aimed to validate the efficacy of bacterial ghosts as an oral vaccine by administering them to Cyprinus carpio and evaluating the resultant innate and acquired immune responses. Following immunization, the vaccinated Cyprinus carpio were exposed to a lethal dose of the wild-type bacterial strain to assess survival rates and relative protection efficiency. Results: Oral vaccination with bacterial ghosts led to the significant enhancement of lysozyme (LZM) and myeloperoxidase (MPO) activity in koi serum. It also resulted in the upregulation of cytokines, such as IL-2 and TNF-α, as well as an increase in both systemic (IgM) and mucosal (IgZs) antibody responses. The immunized group demonstrated reduced cumulative mortality following bacterial challenge. The relative percent survival in the vaccinated group reached as high as 87.50%. Conclusions: The oral immunization of Cyprinus carpio with A. veronii-derived bacterial ghosts confers substantial immune protection, providing a foundational basis for the development of novel vaccines against A. veronii.

As one of the major environmental factors, photoperiod plays an important role in factory aquaculture systems, and the effects of photoperiod on organism performance appear to be species specific. To determine a suitable light photoperiod that optimizes production efficiency, the effects of three commonly used photoperiods 12L (12 h light):12D (12 h dark), 24L and 24D on body composition and antioxidant capacity of juvenile fat greenling Hexagrammos otakii were assessed. The initial weight of the fish in this feeding test was 11.07 ± 0.16 g, and the trial lasted for 30 days. The effects of these three photoperiods on growth performance were also tested. Juvenile fat greenling reared under 24D shows significant growth performance, with significantly higher feed efficiency and significantly lower feed rate. However, there was no significant difference in growth performance between the other two treatments. On the 10th day of the experiment, the hepatic antioxidant enzyme activities in 24L and 12L:12D treatments were all significantly greater than those in 24D treatment. However, at end of the culture trial, hepatic antioxidative enzyme activity was suppressed, and the highest malondialdehyde concentration was observed at 12L:12D, followed by 24L and then by 24D, implying relatively greater degree of oxidative damage to lipids and proteins in 12L:12D and 24L groups. The photoperiod affected the muscle fatty acid (FA) level, and the level of FA was significantly higher in the 24D group than in the other two groups. The levels of saturated fatty acids (especially C24:0) and monounsaturated fatty acids (especially C18:1n-9) were significantly lower in the 12L:12D and 24L groups. The effect of photoperiods on the total muscle protein content of fat greenling juveniles was limited. Nevertheless, an obvious effect on amino acid composition, especially essential amino acid (EAA) composition, was observed, and the EAAs in the muscle of juveniles were sharply consumed to physiologically adapt to environmental variations in the 12L:12D and 24L treatments. These findings suggest that constant darkness promotes better growth, body composition and antioxidant capacity in fat greenling juveniles and that a changing photoperiod (light-dark conversion) may cause more stress in this reef-dependent species.

This study addresses challenges in the breeding and domestication of mandarin fish (Siniperca chuatsi) in Tianjin, China, focusing on improving survival and feeding acclimation rates. A comparative analysis of single-injection and double-injection spawning methods was conducted, along with evaluating common carp (Cyprinus carpio) as initial feed. The results revealed significant differences in effect duration, with natural spawning (37.2 ± 0.8 h) being the longest, followed by the one-injection method (24.5 ± 0.5 h), and the two-injection method (18.5 ± 0.5 h). Fertilization rates also differed significantly, with the one-injection (81.33 ± 2.40%) and two-injection methods (83.03 ± 2.41%) outperforming natural spawning (73.50 ± 3.75%). The growth curves of both common carp and mandarin fish displayed nonlinear trends over time, supporting the feasibility of using common carp as an initial feed for mandarin fish. The industrial aquaculture model successfully maintained high water quality, highlighting its effectiveness in water purification. After 60 days of domestication, 91,819 juvenile mandarin fish with an average size of 7.8±0.15 cm were harvested, achieving a feed conversion ratio of 2.2 and a survival rate of 18.65%. This study demonstrates the potential for large-scale aquaculture and industrial development of mandarin fish in northern China, providing valuable insights into improving breeding and acclimation processes.

The CYP315A1 gene in Macrobrachium nipponense (named Mn-CYP315A1) was characterized from the “Insect hormone biosynthesis” signaling pathway in the hepatopancreas transcriptomes. The total cDNA length of Mn-CYP315A1 was 1582 bp, encoding 569 amino acids. It contained typical P450conserved domains. qPCR analysis indicated that this gene was highly expressed in the ovaries of adult females (P < 0.05), moderately expressed in their heart (P < 0.05), and minimally expressed in other tissues (P < 0.05). The expression of Mn-CYP315A1 was relatively stable during embryonic stages (CS to ZS) and from hatching to metamorphosis (L1 to L10) (P > 0.05), and increased significantly on the 10th day after metamorphosis (P < 0.05). Expression in mature ovaries increased sharply (P < 0.01), while it was relatively low in other stages (P < 0.05). In situ hybridization results showed that it was mainly expressed in the cytoplasmic membrane and nucleus of oocytes, and the signal was strongest during the mature stage (Ⅳ stage) and weakest during the non-development stage. The RNA interference results showed that the GSI and the cumulative proportion of ovary stage Ⅲ in the experimental group were significantly lower than those in the ds-GFP group after injection with CYP315A1 dsRNA (P < 0.05). The cumulative molting frequency of the ds-GFP group was about 2.5 times that of the ds-CYP315 A1 group. These results suggest that Mn-CYP315A1 has a dual role in promoting ovarian development and molting in female M. nipponense.

Artificial breeding of mantis shrimp Oratosquilla oratoria, using the ecological breeding in earthen pond (EBEP) method, has been carrying out from 2019, and the produced larvae have always been used for supportive breeding programs in Bohai Bay. To assess the degree of fidelity of enhancement programs used an EBEP method to native genetic pools, genetic diversity at 10 microsatellite loci was analyzed in three hatchery offspring populations, their wild parent stocks, and their wild contemporaneous offspring. Significant decrease in the almost genetic diversity parameters and highly significant differences in shannon's information index (decreasing by 22.54%-40.97%) and allelic richness (33.80%-46.87%) were observed between in hatchery populations. This further created relatively more genetic differentiation between the hatchery and wild population, as the pairwise Fst values and genetic distances showed. The mean pairwise relatedness coefficients showed higher values within hatchery populations and lower values within wild populations. Hatchery populations contained the fewest full-sib families and offspring were extremely distributed in 10-11 full-sib groups in each hatchery population. The relatively small number of actual spawning females and large variance in parental contribution to the next generation possibly causes allele reduction in the hatchery population, which in turn leads to a decrease in allelic diversity and an increase in genetic similarities among individuals. Promoting synchrony of ovarian development in females, providing good conditions for incubation and larvae culture and balancing the contributions of parents will be important in future breeding propagation.

The transcriptomes of skin were sequenced in two types of monochromatic red common carp（Cyprinus carpio） with body length of（33.42 ±0.24） cm and yellow common carp with body length of（38.75±0.43） cm using Illumina Hi-seq sequencing technology, and differentially expressed genes were identified and selected for analysis in order to investigate the genetic resources of whole red and yellow common carp. The results showed that 129 222 850 clean reads were obtained in whole red and 130 869 572 in whole yellow common carp. Comparison with known genes 58 782 genes were annotated in the Nr, 61 490 in Nt, 11 468 in COG, 31 206 in GO, 31 581 in KEGG, 61 385 in Pfam and 51 805 in Uniprot databases, with 8 378 genes annotated in all seven databases. There were 4 822 differentially expressed genes in skins of whole red and yellow common carp, with 1 929 significantly up-regulated and 2 893 significantly down-regulated. Further clustering analysis of differentially expressed genes revealed similar patterns of high and low expression of differentially expressed genes in both skin samples. The reliability of transcriptome data results was confirmed by qRT-PCR validation of 9 differentially expressed genes, in which some genes found here were involved in body color regulation, such as mitfa, ednrA, wnt7, agouti and mif. KEGG analysis revealed that differential genes were significantly enriched in 43 pathways, including mannose and fructose metabolism, glycolysis/gluconeogenesis, carbon metabolism, pentose phosphate pathway and tyrosine metabolism. The analysis of tyrosine metabolism and melanin synthesis pathways showed that mif, mif4g, agouti, ednrA and ednrB were significantly upregulated and tyr, tyrp1, mitfa and wnt7 were significantly downregulated in genes related to red and yellow pigment synthesis. Analysis of differential genetic variation indicated a total of 388 673 single nucleotide polymorphism（SNP） markers in both whole red and whole yellow common carp. The findings indicated that the differentially expressed genes in the skin tissues of two monochromatic common carp were primarily enriched in energy metabolism, growth, and immunity pathways. The transcriptome data obtained can be used to develop molecular markers as well as cloning, editing, and functional analysis of functional genes in koi.

为提升本地区大口黑鲈(Micropterus salmoides)苗种供给率、促进渔民增产增收,开展了大口黑鲈反季节规模化繁育试验.通过温度调控、营养强化等手段分 4 批次培育亲鱼 20734 尾,并采用人工催产、自然产卵、工厂化集中孵化的方法生产水花苗种 54385 万尾;经实际统计和测算,试验期间亲鱼平均催产率为77%,亲鱼平均回收率为78%,受精卵平均孵化率为 93%.通过效益分析得出:按单位体重计算亲鱼培育平均成本为5.2元/kg;水花生产投入平均成本为 44.5元/万尾;生产水花的平均收益为 218.6元/万尾.总结:影响大口黑鲈水花生产效益的主导因素在于水花的价位,所以应充分把握8-9月间的价格高位期,以实现利益最大化.

2.取卵方法 雌鱼含卵孵化一般会持续20天左右,鱼苗才能发育成熟,在此之间雌鱼一直处于不进食的状态,身体消耗巨大.雌鱼在孵化期间受惊后会出现吐卵或吞卵的情况,影响孵化率.在工厂化养殖中,为保证阿里鱼的出鱼率,同时做到苗种规格一致,一般会采取取卵后统一孵化的方法.

马拉维湖慈鲷(简称"马鲷")是淡水观赏鱼市场中炙手可热的养殖品种.雄性成鱼具有体色丰富、体形适中、适应性强等特点,深受消费者的喜爱.阿里鱼(Sciaenochromis fryeri)属硬骨鱼纲、鲈形目、慈鲷科、鬼丽属,是马鲷中极具特色的品种.雄鱼体长5～8厘米时就可发色,且颜色多为亮丽的金属蓝色.随着个体生长,体色逐渐加深为深蓝色,并从吻端到背鳍出现明亮的白色边缘,具有很高的观赏价值,素有"蓝色闪电"之称.现将阿里鱼工厂化繁养技术总结如下.

为评价不同遗传背景群体与养殖模式对大口黑鲈(Micropterus salmoides)肌肉营养成分的影响,优化养殖组合并引导消费,实验选择2个鲈鱼苗种群体为材料,搭配2种模式,设定4个组,经8个月养殖后,按国标法检测各组样本肌肉营养成分并进行分析.结果显示,C组肌肉含水量显著低于其他组(P＜0.05),粗蛋白含量显著高于其他组(P＜0.05).B 组 ∑TAA、∑EAA、∑NEAA、∑HEAA、∑DAA、∑EAA/∑NEAA等指标均显著高于其他组(P＜0.05);B、C、D组各样本∑EAA/∑TAA值差异不显著(P＞0.05),但B组∑EAA/∑TAA值显著高于A组(P＜0.05);各组之间的∑DAA/∑TAA值无显著差异(P＞0.05).A组样本共获得16种脂肪酸含量数据,B和C组分别获得13种脂肪酸含量数据,D组获得12种脂肪酸含量数据;B组SFA、MUFA、EPA+DHA、PUFA、UPA、FA等指标均显著高于其他实验组(P＜0.05),只有UFA/SFA这一指标显著低于C和D组(P＜0.05),但与A组差异不显著(P＞0.05).各组所测得4种常量元素中K含量最高,且B组的含量(4239.33 mg/kg)显著高于其他各组(P＜0.05);Na含量次之,且B组的含量(306.87 mg/kg)显著低于其他各组(P＜0.05).综上,池塘工程化循环水槽养殖的YL3产品有一定的蛋白质积累优势;传统池塘养殖TL的产品有一定的氨基酸和脂肪酸含量优势,并具有较高的钾钠比.

试验旨在研究不同饵料强化剂对红翅白马王子幼鱼生长、体色和生化指标的影响.选取体重0.12g的红翅白马王子幼鱼分别为投喂饵料组(A组)、未强化卤幼组(B组)、螺旋藻粉强化卤幼组(C组)、酵母强化卤幼组(D组)、鱼肝油强化卤幼组(E组)和藻粉鱼肝油强化卤幼组(F组),其中A组为对照组,每组每缸放入50尾试验鱼,每组3个重复.试验期4w.结果表明:试验组幼鱼的终末体长、末重、体重增长率均显著高于对照组(P＜0.05),其中D组鱼的数据均为最高,具有明显优势.D组幼鱼的肥满度显著高于除对照组外的其他组(P＜0.05).C组、D组、F组幼鱼的亮度(L*)值显著低于对照组(P＜0.05);B组、C组和F组幼鱼的红度(a*)值显著高于对照组(P＜0.05);B组、C组、D组、F组幼鱼的黄度(b*)值均显著高于对照组(P＜0.05).C组、E组幼鱼的肠道胃蛋白酶和胰蛋白酶活性均显著高于对照组(P＜0.05),B组显著低于对照组(P＜0.05),D组幼鱼肝脏中胃蛋白酶活性显著低于对照组(P＜0.05);C组幼鱼肝脏胰蛋白酶活性显著高于对照组(P＜0.05).研究表明,饵料强化对红翅白马王子幼鱼的生长、体色和消化酶指标影响较明显,添加藻粉组在改善幼鱼体色和提高消化酶活力等指标具有明显优势.

为探索饲料中添加雄烯二酮和睾酮对阿里雌鱼生长及体色的影响,将810尾初始体质量为5.78±1.05 g的阿里雌鱼随机分为9组,每组3个平行,每个平行30尾鱼,对照组投喂基础饲料,试验组分别投喂含100,200,300,400 mg/kg雄烯二酮(A100,A200,A300,A400组)和100,200,300,400 mg/kg睾酮(T100,T200,T300,T 400组)8个浓度梯度的饲料.观察8周增色时间和4周停药期鱼的生长及体色变化情况.结果显示:不同浓度的雄烯二酮和睾酮对阿里雌鱼的成活率没有影响,均为100％.A200组的阿里雌鱼特定生长率(SGR)最高,为0.39,显著高于T100,T200,T400组和对照组(p<0.05).8周增色后,A300组的阿里雌鱼体色总色差值(△E*ab)、黄蓝度值(b*)与A400,T300组差异无统计学意义(p>0.05),但均小于其他各组(p<0.05);在后4周停药期中,体色呈现先增艳后又缓慢减弱的现象,仍维持在体色较艳的程度.结果表明,饲料中添加雄烯二酮比睾酮更有效地促进了阿里雌鱼的生长和增色,A300,A400组增色后的阿里雌鱼体色能够稳定4周,阿里雌鱼适宜增色剂及添加量为雄烯二酮300 mg/kg.

为探明甲基睾酮对阿里雌鱼生长及体色的影响,在水温22～24℃下,将初始体质量(5.78±1.05)g的阿里雌鱼450尾随机分为5组,每组3个平行,每个平行30尾,饲养于75 cm×60 cm×28 cm水族缸中,分别投喂含甲基睾酮0、4、8、12、16 mg/kg 5个梯度的饲料,观察8周增色时间和4周停药期鱼的生长及体色变化.试验结果显示,不同含量的甲基睾酮对阿里雌鱼的成活率无影响,均为100％;12 mg/kg的甲基睾酮组的体质量显著高于其他各组(P<0.05);12 mg/kg与16 mg/kg甲基睾酮组增色效果差异不显著(P>0.05),但显著高于其他各组(P<0.05);增色后的阿里雌鱼在后4周停药期中,体色呈现先增艳,后又缓慢减弱现象,但仍维持在较艳的程度.表明外源甲基睾酮对阿里雌鱼具有适应性反应,增色后的阿里雌鱼体色能够稳定4周以上,甲基睾酮适宜添加量为12 mg/kg.

研究不同光照周期(长光照18L﹕6D、短光照8L﹕16D、连续光照24L﹕0D、连续黑暗0L﹕24D和对照组12L﹕12D)条件对锦鲤(Cyprinus carpio)生长、能量收支及生物钟基因相对表达量的影响,实验周期为90d.结果表明,在整个试验周期,各光周期处理组成活率无显著变化(P>0.05),24L组和18L﹕6D组饲料系数显著低于12L﹕12D组、8L﹕16D组和24D组(P<0.05).终末体重、特定生长率在实验前30d内受光照影响不大(P>0.05),而实验30d后出现显著变化,延长光周期尤其是连续光照会显著增加终末体重和特定生长率(P<0.05);对比连续黑暗0L﹕24D组,其他光周期处理组锦鲤摄食能分配在代谢和生长的比例显著增加(P<0.05);4个生物钟相关Clock、Per2、Cry1和Bmal1基因相对表达水平无明显规律.综上所述,延长光照时间,尤其是连续光照有利于锦鲤幼鱼的生长和发育.

为探究CYP17a1基因在锦鲤(Cyprinus carpio)性腺不同发育时期的作用及其在不同组织中的表达水平,采用实时荧光定量PCR和蛋白质免疫印迹(Western blot)技术,分析了细胞色素CYP17a1基因在1～3龄锦鲤成鱼性腺发育6个时期(Ⅰ期、Ⅱ期、Ⅲ期、Ⅳ期、V期、Ⅵ期),及精巢(卵巢)、脑、肌肉和肾脏等不同组织中CYP17a1 mRNA和蛋白质的表达情况.结果显示,1～3龄锦鲤雌鱼、雄鱼性腺发育不同时期成熟系数(GSI)变化规律基本相同,其中3龄锦鲤性腺V期时最高,但卵巢GSI明显高于精巢.CYP17a1 mRNA在卵巢、精巢、脑、肌肉和肾脏都有表达,各组织表达量存在显著差异(P＜0.05),表现为精巢＞卵巢＞肌肉＞肾脏＞脑,卵巢、精巢的表达量随着年龄增加有升高趋势,在脑、肌肉和肾脏中无明显年龄差别.CYP17a1基因在1～3龄锦鲤卵巢、精巢的6个不同发育时期表达量均值呈现先降低后升高趋势,并呈现出随年龄增长,表达量显著升高的现象.3龄锦鲤精巢Ⅰ期表达量最高,是同龄锦鲤精巢Ⅲ期和Ⅳ期表达量的2.75倍和3.13倍.Western blot检测结果显示,CYP17a1蛋白表达水平与mRNA表达水平一致.以上研究结果表明,细胞色素CYP17a1基因在锦鲤性腺发育中发挥着一定作用,可能在精巢发育及精子细胞分化成熟方面具有重要促进作用.

为探索南美白对虾(Litopenaeus vannamei)绿色高效养殖技术模式,构建了南美白对虾套养地图鱼(Astronotus ocellatus)生态养殖技术模式,经过4个月的养殖试验,结果显示:南美白对虾平均单产2 700 kg/hm2,平均利润可达107 490元/hm2,池塘中套养地图鱼可有效预防南美白对虾疾病的传播.表明该模式符合水产养殖绿色发展方向,具有推广应用价值.

血鹦鹉鱼由紫红火口鱼和红魔鬼鱼杂交所得,遗传了来自两种鱼所特有的生理习性,易养,全身鲜艳通红,加上胖嘟嘟的体形和柔柔的鳍条,非常惹人喜爱.血鹦鹉鱼因有红红火火等美好寓意,养殖技术又比较简单,成为家庭养殖热带观赏鱼的首选.随着血鹦鹉鱼家庭水族缸养殖人群逐渐增多,为了更好地服务消费者及促进血鹦鹉鱼产业的健康发展,近年来,天津市观赏鱼技术工程中心开展了血鹦鹉鱼水族缸式养殖技术研究,取得了一些技术成果.现将血鹦鹉鱼水族缸养殖技术总结如下.