Melanized focal changes in skeletal muscle in farmed Atlantic salmon after natural infection with Piscine orthoreovirus (PRV)

Melanized focal changes in skeletal muscle of farmed Atlantic salmon (Salmo salar) are a major quality problem. The aetiology is unknown, but infection with Piscine orthoreovirus (PRV) has been associated with the condition. Here, we addressed the pathogenesis of red and melanized focal changes and their association with PRV. First, a population of farmed fish (PRV‐negative prior to sea transfer) was sequentially investigated throughout the seawater period. The fish were autopsied and tested for PRV infection. Muscular changes were described by macroscopy and histology, and a classification system was established. Second, in an experimental infection trial, PRV was injected intramuscularly to induce changes. The farmed fish was gradually infected with PRV. Red focal changes occurred throughout the observation period with a low prevalence regardless of PRV status. Melanized changes were highly diverse and their prevalence increased during the trial. Changes of low macroscopic grade and histological category were more prevalent in PRV‐negative fish. Diffuse granulomatous melanized changes only occurred after PRV infection. No muscular changes were observed in the experimentally challenged fish. Our studies do not indicate that PRV infection causes red focal changes, but seems important in the development of granulomatous melanized changes.     

Histological alterations in the hepatopancreas of Penaeus monodon Fabricius (1798) given aflatoxin B1-incorporated diets

Aflatoxin is a toxic contaminant produced by toxigenic fungi of the genus Aspergillus during the processing and storage of feeds and feed ingredients. Aflatoxins can cause abnormalities such as poor growth, physiological imbalances and histological changes that result in a reduction in the yield and profitability of shrimp culture. Histological changes in Penaeus monodon sub-adults fed different doses of aflatoxin B₁ were studied. The doses of aflatoxin B₁ administered in the diets were 50, 100, 150, 500, 1000 and 2000 ppb. At the end of the fourth and the eighth weeks of the experiment, the shrimps were sampled and the cephalothorax was observed for histological changes. Significant changes were observed in the different treatment groups at the fourth and eighth weeks. The severity of pathological changes was proportional to the increase in the concentration of aflatoxin fed to the shrimps. Histological changes in the hepatopancreas were loss of structure of the cells and tubules, nodule formation, cell elongation, desquamation, rounding of cells, fibrosis, necrosis, haemocytic infiltration and cellular inflammation.     

电磁场对小球藻生理特性的影响及其机理分析

采用稳恒电磁场的循环磁处理方式培养小球藻,对其生长、色素和元素积累量等变化进行研究,同时探讨了小球藻电磁场效应的可能机理。研究发现不同的电磁场强度对小球藻生长的作用不同,磁处理对小球藻细胞的色素组成没有影响,只是改变其含量;藻细胞官能团没有发生变化;磁处理对于小球藻中的微量元素积累会产生较大程度的影响,尤其是金属离子。电磁场的生物效应可能来源于离子吸收过程的改变。     

Numerical and behavioural response of cyprinids to the introduction of predatory brook trout in two oligotrophic lakes in northern Ontario

Abstract –  Response of potential prey to the introduction of piscivores in a whole ecosystem is generally inferred from small-scale studies. Using distance sampling, two lakes that were initially without predators and three control lakes where predators were previously present were examined for the response of prey species to the introduction of brook trout ( Salvelinus fontinalis ). Responses monitored included numerical changes in abundance, changes in habitat use patterns, and changes in the mean shoal sizes of potential prey species. No statistical changes in abundance or habitat use patterns were detected, whereas there was a significant increase in the mean shoal sizes of potential prey species in lakes where predators were added. We conclude that, in some natural systems, shoaling may be the first response potential prey initiate to reduce mortality risk.     

黑龙江水系不同水域水质的理化特征

报道了2001年5-9月黑龙江水系不同水域理化特征和季节变化动态。结果表明:该水系不同水域水质基本处于良好状态,其透明度均值为41cm,pH均值为7.45,水呈中性,水中溶解氧丰富,水型属重碳酸盐类,钙组Ⅰ型(CCaI)和软水。水中主要营养元素含量较高,总氮均值为0.483mg·L-1,磷酸盐含量较低。水中多数理化组分在平面和季节分布上有所差异,但差异不明显。文中对水质理化特性与季节变化和主要理化指标、营养状况及其与鱼类为主的水生生物的相关性进行了讨论和评价,为发展水产业和持续利用渔业资源提供了一定的理论基础依据。     

The effect of dietary lipids on the trout erythrocyte membrane

Rainbow trout were fed either a commercial diet or semi-purified diets containing 8% by weight of either cod liver oil, grape seed oil or hydrogenated coconut oil. Important changes in the fatty acid composition of erythrocyte membrane phospholipids were induced by these dietary fats. No changes were seen in the cholesterol/phospholipid ratio and in the cellular ATP level. Shape changes (crenation of cell margin and shrinkage) were only seen in trout fed hydrogenated coconut oil in connection with an accumulation of high amounts of (n-9) fatty acids including 20:3 (n-9) phospholipids. The compositional changes affect the stability of the erythrocyte membrane. An increased rate of osmotic hemolysis appeared to be associated with an increased unsaturated fatty acid content of the membranes.     

嗜水气单胞菌源黄鳝出血病的组织病理学研究

应用组织学方法研究了分离自患出血病黄鳝(Monopterus albus)体内的嗜水气单胞菌(Aermonas hydrophila)人工感染健康黄鳝后引起的组织病理学变化。结果显示:健康黄鳝感染嗜水气单胞菌后发病呈急性过程,感染后15~33 h为发病死亡高峰期。黄鳝人工感染后出现的临床症状与自然发病病例相似,主要表现:体表出现出血斑、肛门红肿、腹腔充血以及各实质性器官出血、充血。人工感染黄鳝的肝脏、脾脏和肾脏的病理变化明显:肝脏出现广泛的充血、出血,肝细胞出现空泡变性、坏死;肾脏肾小管上皮的肿胀、结构的消失,肾小球出血、变性坏死;脾脏充血、出血;肠粘膜上皮脱落,基底膜排列紊乱,大量出血。结果表明,嗜水气单胞菌感染黄鳝后的病理变化主要表现为肝脏、肾脏等实质性器官充血、出血,及广泛的组织细胞变性和坏死。     

Changes in smooth muscle contractility of rainbow trout (Oncorhynchus mykiss Walbaum) intestine during acclimation to altered temperature

The effects of altered water temperature in vivo on in vitro smooth muscle contractility of rainbow trout intestine were investigated. Temperature has a significant effect on receptor-mediated intestinal smooth muscle contractility in the rainbow trout. The efficacy of 5-HT, carbachol, and transmural stimulation increased with temperatures above 10°C, with an optimal increase at 15°C. There was also a modest increase in the potency of 5-HT and carbachol within 2 days of establishing trout at 20°C. By day 8, most of these changes had either stabilized or were returning to control values, suggesting that acclimation changes in membranes and enzyme activities were taking effect. However, the contractile responses to carbachol and transmural stimulation were still increasing at this time. This may imply that the muscarinic receptors are more resistant to membrane acclimation changes and may take longer to adapt. Because these experiments were controlled for handling stress and seasonal changes that affect contractility, we have been able to demonstrate some early changes in smooth muscle contractility that occur during acclimation to altered temperature.     

Histopathology of vitamin C deficiency in a cichlid, Cichlasoma urophthalmus (Günther)

Abstract. This paper describes the histopathological changes observed in the Mexican native cichlid Cichlasoma urophthalmus (Günther) when try with an initial weight of between 160 and 170 mg were fed with diets deficient in vitamin C for 90 days. The epidermis showed an extensive inflammatory response, with spongiosis and also degenerative changes in the basal cells. Muscle showed a range of pathological changes including inflammation, changes in the number and position of the nuclei, vacuolation and necrosis, granular degeneration, and fibre loss. Gills showed thickening of the primary lamellae, oedema, hyperplasia, telangiectasis and atrophy of the bony supporting structures. Ganglia and neurones of nervous tissue were abnormal with changes which ranged from slight inflammation to central chromatolysis. The hepalopanereas was also affected and focal necrosis of the hepatocytes was frequently observed. The pancreas showed major changes with shrinkage of the acinar cells and reduction of zymogen granule content. Fish fed diets containing 0 and 40 mg vitamin C kg^-1 of diet were infected with Mycobacterium sp. and miliary tuberculosis was found affecting kidney, spleen, choroid gland, stomach, heart and muscle. The association between fish tuberculosis and vitamin C deficiency is discussed.     

中国明对虾弧菌病的组织病理学研究

本文通过肌肉注射溶藻弧菌 (Vibrioalginolyticus) ,使中国明对虾 (Fenneropenaeuschinensis)感染致病 ,观察并描述了患病对虾的外观症状及有关组织器官的病理变化。结果表明 ,肝胰腺、中肠、心脏、肌肉和鳃等都有不同程度的病变 ,其中尤以肝胰腺最为严重 ,主要表现为细胞坏死、脱落 ,组织变性 ,有的组织间有许多细菌聚集或散布 ,机体有明显的炎症反应。而对照组外观正常 ,组织器官未见病理变化     

Effect of the digenean Isoparorchis hypselobagri (Billet, 1898) on an airbreathing fish Channa punctatus (Bloch) with particular reference to biochemical and haematological changes

Abstract. Morphological, behavioural and haematological changes in Channa punctatus caused by infection with the digenean Isoparorchis hypselobagri are reported. Morphological changes include partial necrosis of fin tissue, scale loss (particularly along the opercula and caudal peduncle) and loss of pigmentation, together with considerable damage to the viscera, especially the gonads, and the abdominal muscles. Behavioural changes include partial or complete loss of equilibrium, irritability and convulsions. Haematological changes observed were a significant decrease in haemoglobin and haematocrit values resulting in hypochromicmacrocytic and normochromicnormocytic anaemia together with an increase in total leucocyte number. Significant decreases in blood glucose level and liver glycogen content were also observed. Some of the changes could be partially compensated by providing a bigger food ration. Compensatory effects were observed for haemoglobin and haematocrit values and leucocyte number. However, an increase in diet could not arrest the significant decrease in blood glucose level and liver glycogen content. The possible effects of parasitism on the utilization and productivity of C. punctatus are discussed.     

Ultrastructural changes in the hepatopancreas of Penaeus monodon Fabricius 1798 given aflatoxin B1 diets

Fungal contamination of shrimp feeds affects the shelf life leading to substantial economic losses. Ultrastructural changes in Penaeus monodon sub‐adults fed three different doses (50, 1000 and 2000 ppb) of aflatoxin B₁ (AFB₁) were studied. At the end of 4 and 8 weeks of experiment, the hepatopancreas of shrimps were observed for ultrastructural changes. The prominent ultrastructural changes in hepatopancreas of the shrimps fed 1000 and 2000 ppb AFB₁ were rupture of cell membrane and microvillus border, damage and swelling of mitochondria, fragmentation of endoplasmic reticulum, nuclear vacuolation, chromatin condensation and autophagy. This study helps to decipher the ultrastructural changes and relate the effects on biochemical, pathological, immunological and histological architecture of the shrimps fed AFB₁‐incorporated feed. The observed ultrastructural changes could serve as indicators in shrimps exposed to toxicants.     

Benthic community changes associated with intertidal oyster cultivation

A study of the environmental effects associated with the trestle cultivation of Pacific oysters, Crassostrea gigas Thunberg, was conducted at a commercial cultivation site in the River Exe estuary, Devon, England. Small, but significant, changes were detected in the macrofaunal community sampled beneath oyster trestles compared with that found in adjacent uncultivated areas. These changes were associated with an increase in organic and silt composition and a reduction in the depth of the oxygenated layer of the sediment beneath the trestles. Water velocity was decreased by the presence of the trestles which probably led to the increase in sedimentation rate observed beneath them. Although biological and physical changes were observed, they were relatively minor compared with the extreme environmental changes associated with the suspended culture techniques used for other bivalve species and fishes. However, other studies suggest that the environmental effects associated with oyster cultivation become more severe in areas of large-scale (hectares) cultivation.     

A study of the sequential clinical and pathological changes during proliferative kidney disease in rainbow trout, Salmo gairdneri Richardson

Abstract. A histological study of 0+ rainbow trout, exposed to proliferative kidney disease (PKD) on an infected farm, showed evidence of infection from the beginning of June, gross pathological changes from the beginning of July, and clinical signs from mid-July. Evidence of healing was present in some samples from the second week of August. Kidney samples were divided into five grades (0–4) representing increasing severity of pathology. A sixth grade (H) was applied to kidneys showing signs of healing. The most frequent clinical signs were abdominal distension and exophthalmos. Melanosis, corneal cloudiness and ecchymoses were observed occasionally. Apart from renal enlargement, other internal gross pathological changes included ascites, gill and liver pallor, oedema, petechiation, and splenic enlargement. The majority of clinical signs and internal changes were only seen in fish with advanced renal swelling (grades 3 and 4). Histopathology was most marked in the kidney and was of three types: haemopoietic hyperplasia, vascular pathology and diffuse inflammatory change. Vascular changes, including occlusion of blood vessels in several organs and apparent haemoglobin crystallization, and destruction of renal excretory structures within areas of chronic diffuse inflammation were marked features of the histopathology in fish with clinical signs. The pathogenesis of PKD is discussed with reference to the histopathological changes.     

Pathology of Edwardsiella tarda infection in turbot, Scophthalmus maximus (L.)

Macroscopic and histopathological changes in cultured turbot, Scophthalmus maximus (L.), in Spain caused by infection with Edwardsiella tarda are described. Eye tumefaction, inflammation, haemorrhages, ascites and the presence of a purulent fluid were the main macroscopic lesions observed. Histopathological lesions were found in the kidney, spleen and liver. In the kidney and spleen these were characterized by a severe apostematous inflammatory reaction, with a large number of abscesses. The liver was affected to a lesser degree and only some phagocytes loaded with bacteria were observed. Ultrastructural observations indicated that macrophages were the main cell type implicated in the inflammatory response. Most of the bacteria observed within the phagocyte cytoplasm showed no degenerative changes and some were dividing. Degenerative changes observed in macrophages indicate their failure in preventing the infection.     

Smoltification in steelhead trout (Salmo gairdneri): Developmental aspects of plasma constituents

Selected biochemical parameters were measured in the plasma of both underyearling anadromous steelhead trout (Salmo gairdneri) and underyearling residentS. gairdneri. The analyses were conducted in an effort to determine whether or not there might be changes which could be associated with the parr-smolt transformation of anadromous strains. Plasma NH⁺ ₄ and plasma Na⁺ were assayed and plasma proteins were analyzed by two-dimensional polyacrylamide gel electrophoresis (2D PAGE). Ammonia was the only plasma ion to show changes with time that were different between the two strains of fish. Proteins prepared by 2D PAGE exhibited developmental changes in both migratory and nonmigratory fish. Each strain exhibited changes with time and the anadromous fish displayed patterns of proteins that were not observed in the nonanadromous strain. It is possible that certain changes in the protein constituents found in anadromous fish are associated with the processes of smoltification. The data are consistent with the notion that this developmental event occurs over an extended period of time and is not restricted to the spring. The data suggest that there may be some changes that occur in certain plasma constituents of migratory fish beginning in the fall and continuing into the spring. The data also indicate that certain ontogenetic events that are not associated with smoltification can be ascertained by analyses of plasma.     

Microfauna associated with amoebic gill disease in sea-farmed Atlantic salmon, Salmo salar L., smolts

A study of microfauna, associated with pathological changes in the gills of Atlantic salmon, Salmo salar L., was conducted over 2001-2002. Monthly samples of 1(+) salmon smolts were taken, protozoan populations were quantified and gill health was assessed histologically. Protozoan densities were correlated with pathological changes, in order to determine their possible role in lesions in the gills. The most severe gill tissue changes were observed in summer/autumn and the least in spring. A diverse polyphyletic protozoan community was observed colonizing the gills, including Neoparamoeba sp., other amoebae, scuticociliates, Ichthyobodo-like flagellates, trichodinid ciliates and prostomatean ciliates. The earlier gill tissue changes in the gill were not always associated with the presence of these microorganisms, whereas amoebae (other than Neoparamoeba sp.), Ichthyobodo-like flagellates and trichodinid ciliates correlated with augmenting gill lesions. Neoparamoeba sp. was present, but its abundance did not correlate with the disease. This study suggests that a diversity of protozoans including Ichthyobodo-like flagellates, trichodinid ciliates and amoebae other than Neoparamoeba sp. are involved in the aetiology of amoebic gill disease in the Irish situation.     

两种高铬日粮对小鼠发育与健康的影响

本实验通过对KM小鼠饲喂铬含量不同的两种日粮,观察了KM小鼠的生长发育情况并测定了体重、主要器官重量等多项生理指标,对主要器官进行了病理的组织学切片观察。结果表明,饲喂2种饲料的KM小鼠的生长发育与对照比较均有明显差异(P<0.05),主要器官重量占体重的比例有明显差异(P<0.05),肝脏、肾脏、肠有不同程度的病变。     

凡纳滨对虾白斑综合征血液病理研究

对自然发病、投喂和注射感染的凡纳滨对虾白斑综合征（white spot syndrome,WSS）血液病理进行研究,结果发现：不同感染方式患病对虾的血液病理变化相似,表现为：1．患病对虾血细胞总数、透明细胞数量极显著减少,小颗粒细胞、大颗粒细胞极显著增加。2．显微病理变化主要表现为血涂片中血细胞明显减少且分布不均匀,破损或解体的细胞增多,呈典型的溶血状态。3．超微病理变化表现为,大部分血细胞坏死,少数血细胞呈不典型的凋亡。患病对虾的血细胞核中可见大量白斑综合征病毒（white spot syndrome virus,WSSV）粒子。病理变化表明血细胞是WSSV的主要靶细胞。     

大黄鱼肝脏病变组织病理学观察

采用石蜡切片和HE染色法,对不同生存条件下的大黄鱼以及肝脏病变的大黄鱼肝组织进行组织切片,在显微镜下进行组织病理学观察,采用酸水解法测定不同生存条件下以及患肝肿大的大黄鱼肝脏的脂肪含量,了解其变化情况。以野生大黄鱼的肝组织细胞结构为参照,初步探明了小网箱养殖大黄鱼的脂肪肝、肝肿大、肝胆汁淤积、肝淤血的组织病理变化情况,讨论了大黄鱼肝脏病变的原因和病变致死原因,并提出了防治措施。