Environmental control of skin colour in the red porgy, Pagrus pagrus

Fish display sophisticated skin chromatic properties that are of considerable ecological, physiological and behavioural importance. The aim of study was to investigate the role of important physical parameters (background colour, lighting spectrum, light intensity and water temperature) on skin colour to gain better knowledge of the environmental factors that regulate pigmentation in cultured red porgy, Pagrus pagrus . All tested physical parameters had a significant effect on skin lightness, especially in the dorsal body area; low light intensity, blue spectrum, a water temperature of 19 °C and a white background significantly increased skin lightness. This effect was mediated through changes in melanophore motility and/or skin melanin concentration. None of the examined factors affected skin hue while a significant decrease in skin entire colour index (a combination of hue and chroma) was found only in white background-adapted fish. It is concluded that all tested physical factors are important regulators of skin lightness.     

正常和白化褐牙鲆皮肤和肌肉中DHA和EPA含量的比较

利用气相色谱法对相同养殖条件下生长的正常和白化褐牙鲆(Paralichthys olivaceus)的皮肤和肌肉组织中的DHA和EPA含量进行了比较分析。结果显示，正常和白化褐牙鲆的皮肤和肌肉中EPA含量相近，但白化个体皮肤中DHA含量显著低于正常个体，约为后者的1／2。而两者肌肉中的DHA含量则没有显著差异。同时，白化个体皮肤和肌肉组织中的DHA／EPA比值略低于正常个体。这一结果证明白化褐牙鲆皮肤蓄积或利用DHA的能力要低于正常褐牙鲆。关于鲆鳔类白化现象同鱼体对饵料中脂肪酸类物质的利用率之间的关系有待深入研究。     

Cutaneous antibodies in excised skin from channel catfish, Ictalurus punctatus Rafinesque, immune to Ichthyophthirius multifiliis

This study determined whether cutaneous antibodies were present in the excised skin of channel catfish, Ictalurus punctatus Rafinesque, immune to Ichthyophthirius multifiliis Fouquet (Ich). Theronts were immobilized on or near the excised skin from immune fish. The survival of immobilized theronts was significantly reduced after exposure for 8 h to the culture of excised skin from immune fish. Culture fluids from excised skin of immune fish immobilized theronts with a peak in the immobilization titre at 24 h post-exposure. Immobility of theronts in the culture fluid from immune skin was removed after immunoabsorption with theronts. Indirect immunofluorescent staining of theronts treated with culture fluid from excised skin of immune fish revealed strong and uniform fluorescence on the cilia and cell surface of theronts. Western blot analysis of the culture fluid from immune fish revealed a 70-kDa band which corresponded to the molecular weight of catfish immunoglobulin heavy chain. The results of this study show that cutaneous antibodies to Ich theronts were present in and released from the excised skin from fish immune to Ich. Immobilization and killing of the theronts are two characteristics of the antibody response that appear to prevent the successful invasion of theronts into excised skin.     

On differences in skin tumours of Pacific and Atlantic Flatfish

Abstract. Pacific flatfish from North American and Japanese coastal waters regularly manifest skin tumours. Those are generally papillomas, which develop from primary inflammatory nodules (vascularized nodules) on fish of a few months's age. Inside the epidermal part of the tumour slightly dedifferentiated malpighian cells change to rounded enlarged cells showing evidence of considerable degeneration (vacuolization and destruction of the cell organelles). These 'X-cells', which compose the major part of the mature tumour, always remain characteristically separated from the surface, from the basal lamina, and from each other, by non-enlarged 'enyelope cells'.
Oval, similarly degenerate cells also occur in the tumour stroma, especially in the nodule-like pre-papillomatous stages and here they originate apparently from fibroblasts.
In the Atlantic, on the other hand, skin papillomas and other neoplastic skin growths occur relatively infrequently. The skin papillomas of Atlantic flatfish are considerably less complex. They belong to the relatively simple type which predominates in fishes in general–hyperplastic epidermal papillae which are supported and natured by branched folds of the dermal tissue (stroma).
Considering the close relationship between the Pacific and Atlantic flatfishes, the distinctive structure of the skin tumours of Pacific fish is considered to be due probably to the influence of a specific virus.     

鱼皮明胶在食品加工业中的应用

明胶是由胶原蛋白部分降解得到的天然多肽聚合物,具有良好的乳化性、成膜性、发泡性和凝胶性以及生物相容性和生物可降解性,在食品加工业中有着广泛应用。哺乳动物明胶占明胶市场的主要份额,但由于存在宗教因素和健康方面的担忧,哺乳动物明胶在食品加工业中的应用受到限制和质疑。鱼皮明胶与哺乳动物明胶具有相似的功能性质,且由于鱼皮明胶来源独特,并能满足伊斯兰教等具有特殊文化和需求人群的要求,已逐渐成为食品加工业中的重点研究对象。为了综合介绍鱼皮明胶在食品中的应用,本文综述了鱼皮明胶作为乳化剂、发泡剂、澄清剂、增稠剂和胶凝剂以及可食用包装、可食用涂层、乳液、微胶囊、纳米纤维和水凝胶制备材料在食品加工业中的研究进展。鱼皮明胶的功能特性使其在食品加工业中可作为食品添加剂、食品包装材料和活性物包裹材料并显示出优于哺乳动物明胶的生物安全性和加工特性。由此可见,鱼皮明胶在食品加工业中具有良好的应用前景,并有望成为哺乳动物明胶的良好替代品。本综述可为今后进一步提高鱼皮明胶的功能性质和扩大鱼皮明胶在食品中的应用提供一定指导。     

Changes in skin mucus of common carp,Cyprinus carpio L., after exposure to water with a high bacterial load

Water in aquaculture systems may contain a high load of microorganisms. Reduction in overall bacterial tank water load improves fish health and growth parameters. In this study, the effect of an increase of overall bacterial load in tank water on carp skin mucus was assessed. Intracellular and released high molecular weight glycoproteins (HMGs) of carp skin mucus were analysed for changes using histological, histochemical and biochemical techniques. Increase of bacterial load did not induce obvious clinical responses in carp, but the skin of exposed carp responded quickly. The amount of skin mucus HMGs isolated increased as well as their total glycosylation. An increased goblet cell number was observed for all carbohydrate stainings, but most clearly for acidic glycoconjugates. A change in the terminal presence of some sugars was also seen. After the initial response of carp, an adaptation to the higher bacterial load in the water appeared to occur as mucins had a higher glycosylation. The changes observed suggest that these skin mucus adaptations are part of a primary defence mechanism of mucosal epithelia, even at a low pathogenic pressure.     

弗氏柠檬酸杆菌感染诱导斑马鱼皮肤免疫相关基因的差异表达

从草鱼肠道中分离到1株细菌,通过形态学观察、生理生化特征和16S rDNA序列分析等鉴定为弗氏柠檬酸杆菌,动物试验结果表明,该菌对斑马鱼有致病性;从感染诱导的斑马鱼皮肤组织中提取总RNA,经Biotin荧光标记与拥有15 617个cDNA片段的斑马鱼基因芯片(affymetrix)杂交筛选分析,获得斑马鱼皮肤免疫相关差异表达基因88个,其中有74个上调表达基因和14个下调表达基因;进一步根据基因功能聚类(GO)分析,初步将88个差异表达基因分为8个生物学功能,其中主要参与补体激活、急性期反应、应激防御反应、细胞凋亡、抗原加工提呈、细胞迁移粘附、凝血因子和血小板激活等免疫应答过程;同时进行信号通路(pathway)分析,结果表明MAPK(hsp70、daxx、nfkbiab)、JAK/STAT(ifn1)和TGF-β(thbs1)等信号通路参与斑马鱼皮肤抗弗氏柠檬酸杆菌感染免疫应答。采用基因芯片方法筛选与鱼类皮肤免疫相关的功能基因,为将来以斑马鱼为模型研究鱼类皮肤局部免疫应答的分子机制提供科学依据。     

Morphological skin colour changes in teleosts

Morphological skin colour change in fish is often referred to in the sole context of background adaptation. It is becoming increasingly apparent that it is a broad phenomenon elicited by a variety of factors. To date, no review has attempted to integrate the different types of morphological colour changes occurring in teleosts, their ecological origins and the regulatory mechanisms involved, often restricting the view on the subject. First, the origin of skin colour is addressed in teleosts including chromatophore type and distribution, pigment biosynthetic pathways and their interactions to one‐another. Second, the different types of morphological colour changes occurring in teleosts are categorized and a key distinction is made between proximate and ultimate morphological colour changes. These are defined respectively as the change of phenotype during an established life‐stage in response to environmental interactions and during the transition between two developmental‐stages phenotypically pre‐adapted to their ancestral ecosystems. Nutrition and UV‐light are primary factors of proximate morphological colour changes beyond the control of the organism. By contrast, background light conditions and social interactions are secondary proximate factors acting through the control of the organism. Highly diversified among teleosts, ultimate morphological skin colour changes are presented in term of alterations in skin structure and pigment deposition during metamorphosis in different species. Finally, the physiological and endocrine mechanisms regulating both proximate and ultimate morphological colour changes are reviewed.     

Histopathology and prevalence of epidermal papillomas epidemic in brown bullhead, Ictalurus nebulosus (Lesueur), and white sucker, Catostomus commersoni (Lacépède), populations from Ontario, Canada

Abstract. White sucker, Catostomus commersoni (Lacépède), and brown bullhead, Ictalurus nebulosus (Lesueur), populations throughout the Great Lakes examined for evidence of pollution associated neoplasia exhibited a variety of morphologically distinct skin lesions. Three types of skin lesions affected white suckers: (a) focal on the lips, (b) discrete on the body, or (c) raised mucoid focal lesions on the skin and fins. Histologically, all three types featured a continuum between mild epidermal hyperplasia and benign papillomata. Brown bullheads exhibited a single variably shaped raised lesion on all body surfaces and within the oral cavity in addition to focal lip lesions. All bullhead lesions exhibited a continuum between mild epithelial hyperplasia and papillomata. Some skin lesions in both species were invasive but most abnormalities represented some stage in the development of epidermal papillomas. These papillomas superficially resemble papillomas common in many fish species and which are associated with viruses, but sucker and bullhead papillomas exhibit a unique range of histopathological and gross morphological appearances. The high prevalence of these papillomas, affecting up to 60% of some populations in polluted areas, supports the possibility that carcinogenic chemicals in the sediments are influencing papilloma development.     

越冬期体色变异红罗非鱼差异表达miRNA的鉴定

为了探究红罗非鱼越冬期体色变异的分子机制，实验构建了其2种体色(正常粉红体色和变黑体色)皮肤组织的小RNA文库，每组4个重复，组装后平均每组分别获得12 190 544和11 891 890条过滤后的读长(clean reads)，获得miRNA成熟序列669个，其中337个是已知的miRNAs。鉴定出越冬期变黑体色相对于正常粉红体色鱼的差异表达miRNAs 26个，其中上调11个，下调15个，且12个为已知的miRNAs，可能在红罗非鱼越冬期体色变异过程中发挥重要作用。富集分析发现了大量代谢和体色调控相关的通路。研究表明，红罗非鱼越冬期的体色变异可能是色素细胞的增殖和迁移形成的，与代谢相关的调控通路在其中发挥重要作用，为解析红罗非鱼越冬期体色变异的机制奠定了基础。     

cDNA芯片技术筛选斑马鱼皮肤免疫相关差异表达基因

研究旨在筛选与鱼类皮肤免疫相关的功能基因,试图解释鱼类皮肤局部免疫应答的分子机制.采用斑马鱼(Danio rerio)基因cDNA芯片(affymetrix),以葡萄球菌(Staphylococcus sp.)感染诱导的成体斑马鱼为实验动物模型,从斑马鱼皮肤组织中提取总RNA,经Biotin荧光标记与拥有15 617个cDNA片段的基因芯片杂交,对斑马鱼皮肤组织中基因表达谱进行初步分析.在斑马鱼皮肤组织中共检测出175个差异表达基因,其中有150个上调表达基因(ratio＞2.0)和25个下调表达基因(ratio＞0.5);在皮肤组织150个上调基因中,91个为已知功能基因,59个为未知功能基因.根据基因文库同源功能基因(GO)分析,将175个差异表达基因分为13个主要的生物功能与代谢通路,其中参与免疫应答相关基因包括鱼主要组织相容性复合体(MHC)I类基因区的基因(UEA,UFA)、补体(Clq,C7-1)、凝集素(HBL3,LGALS1L3)、应急反应生长基因(EGR-1)、肿瘤坏死因子超家族基因(TNFSF10L4)、凝血因子(F5)、转铁蛋白基因(TF-α)和一些蛋白酶等.结果证实,MHC I类分子、补体、凝集素和蛋白酶等参与鱼类皮肤的抗葡萄球菌感染免疫应答,为将来以斑马鱼感染模型研究皮肤局部与细菌的互作机制提供了科学参考;同时表明采用基因芯片方法初探斑马鱼皮肤免疫系统是基本可行的.     

Ichthyophthiriasis in carp, Cyprinus carpio L.: fate of parasites in immunized fish

Abstract. The host-parasite relationship between O-group carp and the ciliatc Ichthyophthirius multifiliis Fouquet was investigated, with the specific aim of characterizing the fate of parasites encountering immunized fish. Carp were immunized by repeated controlled infections; immunized fish and control fish naive to I. multifiliis were then infected in the caudal fin epidermis by a single controlled exposure to theronts, which were applied in a droplet suspension to the tail surface. The number of parasites present within the caudal fin was monitored over a subsequent 5-day period by means of in situ parasite mapping. Results indicated that, contrary to previous reports, theronts penetrated the skin of immunized fish in numbers comparable to those of fish receiving a primary infection. However, the majority of parasites which penetrated immune skin did not complete normal development; 79% of the parasites which had initially penetrated the immune skin were not relocated within 2h of exposure, and since no parasite material was detected at penetration sites, it was concluded that these parasites had prematurely exited the skin rather than been killed in situ. Subsequently, these sites became populated by leucocytes, predominantly macrophages, and the infiltrations continued for up to 5 days after the initial exposure. In contrast, at sites where mature trophonts had exited the skin of fish following a primary infection, more diffuse leucocytic infiltrations were recorded, and these were predominated by neutrophils. Differences in the response to parasite exit from immunized and previously unexposed control fish skin are discussed, with particular reference to the mode of protection and the fate of parasites encountering immune fish.     

Biochemical and histochemical activities of tyrosinase in the skins of normal and albino turbot scophthalmus maximus

Albinism occurr frequently in hatchery-reared turbot, particularly in China. To elucidatethe mechanism of albinism, we comparedthe biochemical and histochemical activity of tyrosinase inthe skins of normal and albino turbot using substrate L-3,4-dihydroxyphenylalanine (L-dopa). It was foundthat: (1) tyrosinase activity existed in allthe skin extracts tested, including pigmented and non-pigmented skins from ocular or blind side of normal and albino turbot, andthe tyrosinase activity ofthe ocular skin extracts was significantly higherthanthat ofthe blind skin extracts from a single individual for both normal and albino turbot. Unexpectedly,the tyrosinase activity inthe extracts from albino skin ofthe ocular side of albino turbot (termed AOA skin) was about 56% higherthanthat from pigmented skin ofthe ocular side of normal turbot (termed PON skin); (2) histochemical staining showedthat tyrosinase activity was present only inthe PON skin but not inthe AOA skin, andthe white skin ofthe blind side of albino (termed WBA skin) and normal turbot (termed WBN skin). A large amount of positive black granules was formed inthe epidermal cells of PON skin but no black granules were formed inthe skins of AOA, WBA and WBN; (3) temperature and salinity have similar effects onthe tyrosinase activity of ocular pigmented and of albino skin extracts, andthe optimal temperature was 5560°C and optimal salinity 26; however, different pH values had different effects onthese tyrosinase activities, andthe optimal pH value of ocular pigmented skin extracts was 7.0 and ocular albino skin extracts 8.0; allthethree activators tested (SDS, trypsin and zymosan) can increasethe activity of tyrosinase in both ocular pigmented and albino skin extracts of turbot. Butthe level of activation onthe ocular albino skin extracts of albino turbot was significantly higherthanthat on ocular pigmented skin extracts of normal turbot.Onthe basis ofthese observations, it is suggestedthat a large amount of wild type tyrosinase is expressed in albino skin butthe tyrosinase activity is blocked by some unknown inhibitory factors andthe blocked activity of tyrosinase can be readily recovered bythe homogenization of skin tissues in vitro.the unknown inhibitory factors need further studying.     

Epitheliocystis Disease in Cultured Yellowtail Seriola mazatlana in Ecuador

Abstract.– Epitheliocystis, a disease of the gill and skin epithelial cells, is reported in the early developmental stages of Pacific yellowtail Seriola mazatlana , a new marine finfish species for aquaculture in Ecuador. Behavior, appearance of infected larvae and clinical signs of infection are described. Light microscopic and histological examinations confirm the presence of intracellular organisms in the gills, skin, nostril and buccal cavity. Proliferative cell response resulted in the gradual destruction of the functional integrity of the gills, causing massive mortalities.     

Effects of dietary lutein/canthaxanthin ratio on the growth and pigmentation of large yellow croaker Larimichthys croceus

This study was conducted to investigate the effects of dietary lutein/canthaxanthin ratio on the growth and skin coloration of large yellow croaker. Five carotenoids supplemented diets were formulated to contain 75/0, 50/25, 37.5/37.5, 25/50 and 0/75 mg kg^?1 of lutein/canthaxanthin. The diet without carotenoids supplementation was used as the control. Fish of the similar size (13.83 ± 0.04 g) were fed with these experimental diets for 8 weeks in sea cages. Results showed that there were no significant differences in survival rate, specific growth rate and feed conversion ratio among the all treatments (P > 0.05). The ventral skin lightness was not affected by dietary treatments (P > 0.05). However, the dorsal skin lightness in the treatment of control was significantly lower than those in the treatments with supplemented dietary carotenoids (P < 0.05). The lowest values of yellowness, redness and carotenoid content both in ventral and dorsal skin were found in the control. Yellowness and carotenoid content both in ventral skin and in dorsal skin decreased with the decreasing of the proportion of dietary lutein. Meanwhile, the redness increased with the increasing of the proportion of dietary canthaxanthin. Fish fed with the control diet had higher melanin content in the dorsal skin, although no significant differences were found. Coloration parameters were linearly related to the carotenoid content in skin. Meanwhile, yellowness, redness and carotenoid content were linearly related to the proportion of dietary lutein. In conclusion, under present conditions, both lutein and canthaxanthin are needed in the diet for large yellow croaker. Compared to the lutein, higher dietary canthaxanthin contents are better for the skin redness.     

大鲵皮肤溃疡死亡相关的微生物区系

为了分析自然环境中病死大鲵和健康大鲵皮肤及水样的微生物区系差异,实验通过高通量16S r DNA的V4～V5区测序,对皮肤微生物区系进行差异分析,探讨大鲵在患病前后微生物区系的变化。健康大鲵和病死大鲵生活水样以及皮肤菌群的多样性、结构和功能存在显著差异。各样品序列标签(Tag)数量平均为97 150条,测序平均长度为400 bp,操作分类单元(OTUs)数据显示,健康大鲵生活水样和皮肤的微生物丰度远远高于病死大鲵。在健康大鲵生活水样中的优势菌群为砷氧化菌属,而当大鲵病死后,其生活水样的优势菌群变为金黄杆菌属。同样,在病死大鲵皮肤样本中金黄杆菌属、丛毛单胞菌属、伯克氏菌目的微生物菌群丰度显著升高,而砷氧化菌属、微小杆菌属、莱比托泉动性球菌等微生物菌群丰度显著下降。同时,病死大鲵皮肤表面有大量溃疡并伴有菌毛,具有典型的伯克氏菌属感染症状。研究表明,大鲵患病死亡前后皮肤微生物区系差异明显,人兽共患病菌伯克氏菌属可能是通过水媒传播感染自然环境下的大鲵并导致死亡的主要病原菌,为科学养殖大鲵、保护野生大鲵以及开发益生菌改善大鲵养殖环境提供依据。     

半滑舌鳎lnc-XR_003049606.1及其靶基因pmelb在无眼侧皮肤黑化过程中的表达

为探究人工养殖半滑舌鳎无眼侧皮肤经常出现黑化现象的成因,实验根据本课题组前期全转录组数据分析结果预测得出lnc-XR＿003049606.1与pmelb在基因层面上存在反式调控的关系。在半滑舌鳎无眼侧黑化皮肤中克隆获得pmelb的c DNA序列。生物信息学分析结果显示,pmelb的c DNA序列全长1 755 bp,编码584个氨基酸,其预测的蛋白分子量为63.94 ku,理论等电点为5.12,预测的二级蛋白结构含有1个Pleckstrin同源域、1个布鲁顿酪氨酸激酶富胱氨酸基序、1个Src同源3域、1个Src同源2域和1个酪氨酸激酶催化结构域。系统进化树分析显示,pmelb与其他鱼类对应的基因聚为一支。氨基酸同源性分析显示,半滑舌鳎的pmelb与大菱鲆和牙鲆的相似性最高(分别为68.05%和66.28%)。分别通过分析半滑舌鳎lnc-XR＿003049606.1和pmelb的表达分析发现,lnc-XR＿003049606.1在1龄半滑舌鳎的皮肤和肝脏中表达,皮肤中表达量在60 d达到顶峰,随着时间延长而降低;而pmelb则主要在皮肤中表达,表达量在时间线上先升高再降低。本研究初步探究...     

川南常羽乌骨鸡肤色的遗传研究与杂交利用

通过对川南常羽乌骨鸡3种羽色系的纯繁、杂交以及与3个浅肤品种的杂交,初步揭示了川南常羽乌骨鸡肤色的遗传现象。结果表明,所用乌骨鸡的肤色主要受遗传控制,存在杂合类型,黑羽系和麻羽系的肤色遗传较为稳定。乌肤性状终生不变,且与趾色、肉骨及内膜色高度相关。乌肤公鸡与不同浅肤母鸡的杂交后代可表现出较高的不同的乌肤比例,表明适当引入浅肤血缘尚可保持乌骨鸡的乌色性状。     

Shading of net cage is an effective control measure against skin fluke Neobenedenia girellae infection in chub mackerel Scomber japonicus

The skin fluke Neobenedenia girellae has become a serious problem in Japan since the 1990s. Present control methods focus on the removal of the attached parasite and these post-infection treatments are often labor intensive, time consuming, and/or stressful to fish. Chub mackerel Scomber japonicus are highly susceptible to N. girellae. However, because of their sensitive nature, bath treatments may cause mortality. In this study, we investigated the efficacy of cage shading to reduce skin fluke infection and the frequency of conventional post-infection treatments. Juvenile mackerel were reared in cages with or without shade for 3 months and their skin fluke infections were monitored. We performed either freshwater baths or oral administration of praziquantel if fluke intensity exceeded the given criteria. In unshaded cages, 3 total bath treatments or 6 total drug treatments were conducted. In contrast, no treatment was required for the shaded cage. The overall fluke intensity in the shaded cage was less than half that of the unshaded cages, despite the lack of treatments. This study demonstrated for the first time the practical use of shading in fish farms to reduce skin fluke infection.