The Effects of Stocking Density and Food Deprivation on Mucous Cells and Lysozyme Activity in the Skin and Gills of Silver Catfish.

This study aimed to identify the regions of the body surface of silver catfish (Rhamdia quelen) with a higher population of mucous cells in the skin. Additionally, the effects of stressful conditions, such as different stocking densities and food deprivation, on the proliferative response of mucous cells in the skin and gill epithelium and their impact on cutaneous mucous lysozyme activity were investigated. Silver catfish were divided into four experimental groups: high stocking density (32 kg/m3) and fed (HSD-F), high stocking density and fasted (HSD-FS), low stocking density (2.5 kg/m3) and fed (LSD-F), and low stocking density and fasted (LSD-FS). Fish in the fed groups received commercial feed twice a day, amounting to 1% of the tank biomass. After a 14-day experimental period, the fish were anesthetized and euthanized. Samples of cutaneous mucous and skin fragments from seven different points and the second left branchial arch were collected. Histological slides of the skin and gills were stained with PAS + Alcian Blue at pH 2.5, and the epidermal mucous lysozyme activity was assessed using the turbidimetric method. The ventral point in front of the ventral fin was found to be the optimal location for collecting cutaneous epithelia due to its higher density of mucous cells. The population of mucous cells in both the skin and gills varied based on the collection point and treatment applied. The highest lysozyme activity in the epidermal mucous was observed in fish from the HSD-F group. Overall, these findings suggest that stocking density and food deprivation create stressful conditions for silver catfish, which modulate their mucosal response to each situation.

Morphological and histochemical features of the digestive tract of Leiarius marmoratus (Gill, 1870).

Leiarius marmoratus, a freshwater catfish from Pimelodidae family, shows great biological and commercial relevance because of its geographic distribution and adaptation to fish-farm. The knowledge of the morphological characteristics of the digestive tract is fundamental to the understanding of fish physiology and nutrition, which helps in the planning of diets to provide better management and success in fish farming. Thus, this work described the morphology and histochemistry of the digestive tract of L. marmoratus adults. After euthanasia, the animals were dissected for analysis of the digestive tract. The oesophagus is a short and distensive organ with longitudinal folds that allow the passage of large food, e.g., other fishes. Oesophageal mucosa layer shows a stratified epithelium with goblet cells and club cells. The secretion of goblet cells is composed of neutral and acidic mucins that are anchored in the epithelium luminal face by epithelial cells fingerprint-like microridges, lubricating the surface to facilitate the food sliding. Club cells have protein secretion that can be involved in alarm signals when epithelium is damaged and in immunological defence. The saccular stomach is highly distensible to store large food. Gastric mucosa layer is composed of epithelial cells with intense secretion of neutral mucin to protect against self-digestion of gastric juice. Cardiac and fundic regions of stomach show well-developed gastric glands composed of oxynticopeptic cells. These cells have numerous mitochondria, highlighting their intense activity in the synthesis of acid and enzymes. The intestine is divided into three regions: anterior, middle and posterior. Although it is a short tube, intestine shows longitudinal folds and microvilli of enterocytes to increase the contact surface. These folds are higher in the anterior region of the intestine, highlighting their function in digestion and absorption. Intestinal goblet cells have acidic and neutral mucins that lubricate the epithelium and aid in digestive processes. These cells increase in number towards aboral, and they are related to the protection and lubrication to expulsion of faecal bolus.

Morphological and histochemical characterisation of the mucosa of the digestive tract in matrinxã Brycon amazonicus (Teleostei: Characiformes).

This study describes anatomical, histological and histochemical features of the digestive tract mucosal layer of the matrinxã Brycon amazonicus, an omnivorous freshwater fish endemic from the Amazon basin. This species presents short thick oesophagus with longitudinal folds, that allow the passage of large food items. The mucosa is lined with a stratified secretory epithelium rich in goblet cells that secrete neutral and acid mucins. The two mucin types provide different viscosity in anterior and posterior oesophagus related to the protective and lubricant functions, respectively. The stomach is a highly distensible Y-shaped saccular organ. Here, it is proposed that this anatomical shape plays an essential role in food storage when food availability is abundant. The stomach mucosa is composed of epithelial cells with intense neutral mucin secretion to protects against gastric juice. The intestine is slightly coiled and presents internally a complex pattern of transversal folds that increases the absorption surface and the retention time of food. Goblet cells in the intestine secrete acid and neutral mucins that lubricate the epithelium and aid in the digestive processes. In the rectum, an increase in goblet cells population occurs that may be related to better lubrication.

The impact of organochlorines and metals on wild fish living in a tropical hydroelectric reservoir: bioaccumulation and histopathological biomarkers.

This study evaluates the contaminants in water and their bioaccumulation in the gills and liver of two ecologically distinct fish species, Astyanax fasciatus and Pimelodus maculatus, living in the reservoir of the Furnas hydroelectric power station located in Minas Gerais in the southeastern Brazil. The histological alterations in these organs are also examined. Water and fish were collected in June and December from five sites (site 1: FU10, site 2: FU20, site 3: FU30, site 4: FU40 and site 5: FU50) in the reservoir, and agrochemicals and metals selected based on their use in the field crops surrounding the reservoir were analyzed in the water and in the fish gills and livers. The concentrations of the organochlorines aldrin/dieldrin, endosulfan and heptachlor/heptachlor epoxide as well as the metals copper, chromium, iron and zinc in the gills and livers of both fish species were higher in June than in December; the liver accumulated higher concentrations of contaminants than the gills. The organochlorine metolachlor was detected only in the liver. The histological pattern of changes was similar in both species with regard to contaminant accumulation in the gills and liver. Fish from FU10, the least contaminated site, exhibited normal gill structure and moderate to heavy liver damage. Fish collected at FU20 to FU50, which were contaminated with organochlorines and metals, showed slight to moderate gill damage in June and irreparable liver damage in the livers in June and December. The histological changes in the gills and liver were suitable to distinguishing contaminated field sites and are therefore useful biomarkers for environmental contamination representing a biological end-point of exposure.

Sex-response differences of immunological and histopathological biomarkers in gill of Prochilodus argenteus from a polluted river in southeast Brazil.

The fish gill is in direct and standing contact with the immediate external environment and, therefore, is highly vulnerable to aquatic pollutants. In this study, Prochilodus argenteus were caught at two different points in São Francisco river. The first point is located near Três Marias dam, while the second is placed downstream the Abaeté river. Chemical approaches showed the presence of metals contamination in the first point. Thus, the main goal of this study was to investigate the possible toxic effects of these contaminants and the likely use of biomarkers on fish gills. Biometric data of length and weight of fish were obtained in order to calculate the condition factor as an organismal biomarker. The histological changes in gills and alterations in mucous and rodlet cells occurrence were detected microscopically and evaluated with quantitative analyses. Myeloperoxidase (MPO) and Eosinophil Peroxidase (EPO) were also assessed in fish gill. The analysis of the water and sediment samples revealed the presence of metals at the two points. As and Cd were detected at higher concentrations at point 1. The presence of lamellar cell hyperplasia, lamellar fusion, lamellar edema and inflammatory foci varied according to the point. Additionally, mucous and rodlet cells and MPO and EPO activities showed variability according to the environmental conditions. Furthermore, with exception of lamellar hyperplasia and eosinophil peroxidase activity, all others parameters showed sex-variation responses. At the first point, male fish showed a chronical inflammation in gills due to the lowest activity of MPO and EPO, as well as low occurrence of inflammatory foci and glycoprotein secretion by mucous cells, while female fish presented an opposite pattern of response to the same environmental conditions. Therefore, we suggest the use of such biomarkers in future monitoring of aquatic systems, taking into account the sex-variation responses.

Avaliação histopatológica e histoquímica das células claras em lesões odontogênicas císticas / Análisis histopatológico y histoquímico de células claras en lesiones quísticas odontogénicas / Histopathological and histochemical analysis of clear cells in odontogenic cystic lesions

Alterações degenerativas e metaplásicas são usualmente observadas no revestimento epitelial dos cistos odontogênicos. Nos tumores odontogênicos estes processos são considerados mais raros. Objetivo: demonstrar a presença de células claras no revestimento epitelial de uma série de lesões odontogênicas císticas. Métodos: realizou-se um estudo descritivo, em uma amostra de 22 lâminas histológicas, do total de lesões odontogênicas císticas procedentes do Laboratório de Patologia Bucal da Universidade Federal da Paraíba. As lâminas foram examinadas por dois avaliadores previamente calibrados e os blocos parafinados correspondentes às lesões em que se observaram células claras, foram novamente processados, e as lâminas foram coradas pela técnica do Ácido Periódico de Schiff após digestão pela diástase e avaliadas quanto à presença de células mucosas. Resultados: células contendo mucina estavam presentes em 12 (54,5 porcento) das lesões coradas pelo Ácido Periódico de Schiff com diástase. Células mucosas foram observadas em 5 (41,66 porcento) dos 12 casos de cistos radiculares, 1 (50 porcento) dos 2 casos de tumores odontogênicos ceratocísticos, nos 4 (100 porcento) casos de cistos dentígeros e em 2 (100 porcento) casos de ameloblastomas unicísticos. Células claras foram muitas vezes observadas em áreas de inflamação. Conclusão: na amostra estudada, células mucosas puderam ser evidenciadas ocasionalmente no epitélio de lesões odontogênicas císticas(AU)

Cambios metaplásicos y degenerativas se observan generalmente en el revestimiento epitelial de los quistes odontogénicos. En tumores odontogénicos estos procesos son considerados raros. Objetivo: demostrar la presencia de células claras en el epitelio de revestimiento de una serie de lesiones quísticas odontogénicas. Métodos: se realizó un estudio descriptivo, en una muestra de 22 cortes histológicos, del total de lesiones quísticas odontogénicas procedentes del Laboratorio de Patología Oral de la Universidad Federal de La Paraiba. Los cortes fueron examinados por dos examinadores calibrados previamente y los bloques de parafina correspondientes a las lesiones que se observaron con células claras se volvieran a procesar y los cortes fueron teñidos por el Ácido Periódico de Schiff después de la digestión por la diastasa y evaluados para la presencia de células mucosas. Resultados: células contiendo mucina estaban presentes en 12(54,5 por ciento) de las lesiones teñidas por el Ácido Periódico de Schiff con diastasa. Células mucosas fueran observadas en 5(41,66 por ciento) de los 12 casos de quistes radiculares, 1 (50 por ciento) de los 2 casos de tumores odontogénicos queratoquísticos, en los 4 (100 %) casos de quistes dentígeros y en los 2(100 por ciento) casos de ameloblastomas uniquísticos. Células claras fueron muchas veces observadas en zonas de inflamación. Conclusión: En la muestra estudiada, las células mucosas pudieron ser encontradas ocasionalmente en el epitelio de lesiones quísticas odontogénicas(AU)

Metaplastic and degenerative changes are usually observed in the epithelial lining of odontogenic cysts. These processes are considered rare in Odontogenic tumors. Objective: to demonstrate the presence of clear cells in the epithelial lining of a series of odontogenic cystic lesions. Methods: a descriptive study was done, in a sample of 22 histological slides of the total odontogenic cystic lesions originating from the Oral Pathology Laboratory at the Federal University of Paraiba. The slides were examined by two calibrated examiners and the paraffin blocks, corresponding to the lesions, where clear cells were observed, were re-processed and the slides were stained by the Periodic Acid-Schiff technique after digestion by diastase and evaluated for the presence of mucous cells. Results: mucin-containing cells were present in 12 (54,5 percent) of the stained lesions by Periodic Acid-Schiff technique with diastase. Mucous cells were observed in 5 (41.66 percent) of 12 root cysts cases, 1 (50 percent) of 2 keratocystic odontogenic tumors, in 4 (100 percent) cases of dentigerous cysts and in 2 (100 percent) cases of unicystic ameloblastomas. Clear cells were often observed in inflammation areas. Conclusion: In the study sample mucous cells could be evidenced occasionally in the epithelium of cystic odontogenic lesions(AU)

Adaptation of the gill epithelium of an euryhaline fish, the guppy (Poecilia vivipara), to freshwater / Adaptação do epitélio branquial de peixes eurialinos, guaru (Poecilia vivipara), para água doce

The south-american euryhaline fish Poecilia vivipara (BLOCH; SNEIDER, 1801), the guppy, is found both in estuary and river waters, which suggests high adaptability to environments of different salinity. In this work we studied the adaptation of the interlamellar, bars and rakers epithelia of the gills of estuary fish to freshwater conditions. The results reveal that the gill epithelia of Poecilia vivipara can adjust itself to freshwater by decreasing the VP of mucous cells of the interlamellar epithelium and increase the volumetric proportion (VP) of chloride cells. However, there was no evidence of similar morphological alteration in the rakers region. The epithelia of the rakers appears to be part of a different compartment that is less sensitive to variation of salinity. (AU)

O peixe eurihalino sul-americano Poecilia vivipara (BLOCH; SNEIDER, 1801), o guppy, é encontrado tanto em estuários quanto em águas de rios, o que sugere uma alta adaptabilidade aos diferentes ambientes de salinidade. Neste trabalho, estudamos a adaptação do epitélio interlamelar, do arco e do rastelo das brânquias dos peixes de estuário de água doce. Os resultados revelam que o epitélio branquial de Poecilia vivipara pode ajustar-se à água doce, diminuindo a proporção volumétrica (PV) de células mucosas do epitélio interlamelar e aumentando a PV de células clorídricas. No entanto, não houve nenhuma evidência de alteração morfológica semelhante na região do rastelo branquial. O epitélio do rastelo branquial parece ser parte de um compartimento diferente que é menos sensível a variações de salinidade. (AU)

Adaptation of the gill epithelium of an euryhaline fish, the guppy (Poecilia vivipara), to freshwater / Adaptação do epitélio branquial de peixes eurialinos, guaru (Poecilia vivipara), para água doce

The south-american euryhaline fish Poecilia vivipara (BLOCH; SNEIDER, 1801), the guppy, is found both in estuary and river waters, which suggests high adaptability to environments of different salinity. In this work we studied the adaptation of the interlamellar, bars and rakers epithelia of the gills of estuary fish to freshwater conditions. The results reveal that the gill epithelia of Poecilia vivipara can adjust itself to freshwater by decreasing the VP of mucous cells of the interlamellar epithelium and increase the volumetric proportion (VP) of chloride cells. However, there was no evidence of similar morphological alteration in the rakers region. The epithelia of the rakers appears to be part of a different compartment that is less sensitive to variation of salinity.

O peixe eurihalino sul-americano Poecilia vivipara (BLOCH; SNEIDER, 1801), o guppy, é encontrado tanto em estuários quanto em águas de rios, o que sugere uma alta adaptabilidade aos diferentes ambientes de salinidade. Neste trabalho, estudamos a adaptação do epitélio interlamelar, do arco e do rastelo das brânquias dos peixes de estuário de água doce. Os resultados revelam que o epitélio branquial de Poecilia vivipara pode ajustar-se à água doce, diminuindo a proporção volumétrica (PV) de células mucosas do epitélio interlamelar e aumentando a PV de células clorídricas. No entanto, não houve nenhuma evidência de alteração morfológica semelhante na região do rastelo branquial. O epitélio do rastelo branquial parece ser parte de um compartimento diferente que é menos sensível a variações de salinidade.

Morphologic analysis of developmental phases and gill ontogenesis in neotropical species Poecilia vivipara (Cyprinodontiformes: Poeciliidae) exposed to different salinities

The present study evaluated and characterized the different phases of development and the cell types present in the gill epithelium of embryos, larvae, and fingerlings of guppy (Poecilia vivipara Bloch & Schneider, 1801) specimens exposed to water with salinity ranging from 0‰ to 20‰. The development of P. vivipara was classified into eight phases. The yolk was intensely eosinophilic, with glycidic and lipidic components between phases 1 to 7. After the development of their branchial epithelium, the presence of pavement cells, mitochondria-rich cells, and mucous cells (MCs) was observed. The understanding of ontogenesis indicates the sequence of cellular origin. Only type IV MCs located in the gill rays was detected from phase 3 through phase 7. Other types of MCs were observed only when the fingerlings were exposed to salinity changes and showed to be lectin-reactive, thus indicating that P. vivipara modulates the cellular behavior when submitted to salinity changes. Exposure to variable saline concentrations did not interfere in the initial development of guppies. The presence of a yolk sac until the fingerling phase characterized this species as ovoviviparous.

Morphologic analysis of developmental phases and gill ontogenesis in neotropical species Poecilia vivipara (Cyprinodontiformes: Poeciliidae) exposed to different salinities

The present study evaluated and characterized the different phases of development and the cell types present in the gill epithelium of embryos, larvae, and fingerlings of guppy (Poecilia vivipara Bloch & Schneider, 1801) specimens exposed to water with salinity ranging from 0‰ to 20‰. The development of P. vivipara was classified into eight phases. The yolk was intensely eosinophilic, with glycidic and lipidic components between phases 1 to 7. After the development of their branchial epithelium, the presence of pavement cells, mitochondria-rich cells, and mucous cells (MCs) was observed. The understanding of ontogenesis indicates the sequence of cellular origin. Only type IV MCs located in the gill rays was detected from phase 3 through phase 7. Other types of MCs were observed only when the fingerlings were exposed to salinity changes and showed to be lectin-reactive, thus indicating that P. vivipara modulates the cellular behavior when submitted to salinity changes. Exposure to variable saline concentrations did not interfere in the initial development of guppies. The presence of a yolk sac until the fingerling phase characterized this species as ovoviviparous.

Morphologic analysis of developmental phases and gill ontogenesis in neotropical species Poecilia vivipara (Cyprinodontiformes: Poeciliidae) exposed to different salinities

The present study evaluated and characterized the different phases of development and the cell types present in the gill epithelium of embryos, larvae, and fingerlings of guppy (Poecilia vivipara Bloch & Schneider, 1801) specimens exposed to water with salinity ranging from 0‰ to 20‰. The development of P. vivipara was classified into eight phases. The yolk was intensely eosinophilic, with glycidic and lipidic components between phases 1 to 7. After the development of their branchial epithelium, the presence of pavement cells, mitochondria-rich cells, and mucous cells (MCs) was observed. The understanding of ontogenesis indicates the sequence of cellular origin. Only type IV MCs located in the gill rays was detected from phase 3 through phase 7. Other types of MCs were observed only when the fingerlings were exposed to salinity changes and showed to be lectin-reactive, thus indicating that P. vivipara modulates the cellular behavior when submitted to salinity changes. Exposure to variable saline concentrations did not interfere in the initial development of guppies. The presence of a yolk sac until the fingerling phase characterized this species as ovoviviparous.

Alterações do epitélio branquial e das lamelas de tilápias (Oreochromis niloticus) causadas por mudanças do ambiente aquático em tanques de cultivo intensivo / The influence of the aquatic environment in tanks sequetially interconnected with PVC pipes on the gill epithelium and lamellas of tilapia (Oreochromis niloticus)

Objetivou-se analisar o comportamento do epitélio branquial de tilápias, cultivadas em tanques posicionados em diferentes altitudes e interconectados por tubos de PVC. Filamentos branquiais de quatro espécimes de quatro tanques (T1, T2, T3 e T4) interconectados seqüencialmente foram submetidos à rotina histológica, para obtenção de cortes de 5µm de espessura, os quais foram corados com Hematoxilina-Eosina, ou submetidos à técnica histoquímica para glicoconjugados: PAS + solução de diástase ou Alcian Blue pH 2,5 ou Alcian Blue pH 1,0. Considerando as regiões basal, intermediária e apical dos filamentos, mensurou-se a área lamelar e contou-se o número de células mucosas em cada uma dessas regiões, o que correspondia a 0,56 mm². Verificou-se que a concentração de oxigênio, pH e a temperatura se reduziam progressivamente com a passagem da água de um tanque para outro. Em função disso, constatou-se um aumento abrupto do número de células mucosas e da área lamelar no T2, e uma redução progressiva destas medidas nos tanques que recebiam água do T2. Além disso, observou-se nos animais do T2, T3 e T4, descolamento do epitélio branquial, hiperplasia celular no espaço interlamelar e telangectasias. Conclui-se que o ambiente aquático de tanques interconectados seqüencialmente por tubos de PVC se altera ao passar de um tanque para o outro, e que estas flutuações físico-químicas se refletem no comportamento do epitélio branquial através de variações da área lamelar e do número de células mucosas.

The behavior of the gill epithelium of tilapias cultured in tanks at different altitudes and interconnected with PVC pipes was analyzed. Gill filaments of four specimens from four tanks (T1, T2, T3 e T4) sequentially interconnected were submitted to histological routine to obtain 5-mm-thick cuts that were stained with HE or submitted to histochemistry reactions PAS + diastase solution or Alcian Blue pH 2.5 or Alcian Blue pH 1.0. Considering the intermediary, apical and basal regions of the filaments, the lamellar area was measured and the amount of mucous cells was counted. It was verified that oxygen, pH, and temperature decreased progressively as the water flew from one tank to another. Thus, an increase was realized of the amount of mucous cells and the lamellar area in T2, as well as a progressive decrease of these measures on the tanks which received water from T2. Moreover, detachment of the gill epithelium, cellular hyperplasia in the interlamellar space, and telangectasias were observed in the fishes from T2, T3 e T4. It was concluded that the aquatic environment in tanks sequentially interconnected with PVC pipes suffers alterations from one tank to another, as that physico-chemical fluctuations reflect on the behavior of the gill epithelium through variations of the lamellar area and the amount of mucous cells.

Efeitos do fluoreto de sódio no epitélio da brânquia do peixe Guaru (Poecilia vivipara) / Effects of sodium fluoride in gill epithelium of Guppy fish (Poecilia vivipara)

O flúor é muito utilizado pelo homem e facilmente encontrado na natureza. Por isso, vários estudos foram realizados visando a toxicidade e o seu efeito cumulativo nos tecidos animais. É descrito que o fluoreto de sódio pode ser empregado no controle do hospedeiro da esquistossomose (Biomphalaria glabrata). Visando a preservação do meio aquático, propõe-se a verificação do efeito do fluoreto de sódio em peixes (Poecilia vivipara). Dez peixes foram submetidos à água declorinada (GC) e o restante foi submetido à água contendo fluoreto de sódio na concentração de 5 ppm (GE), por vinte e um dias. Após esse período, os animais foram sacrificados e suas brânquias foram retiradas. As brânquias foram fixadas, pós-fixadas e desidratadas de acordo com o protocolo das técnicas de histoquímica e análise ultra-estrutural, respectivamente. As peças foram diafanizadas em xilol. Para observação histológica das células mucosas e células do cloro, foi utilizada a técnica de coloração de Hematoxilina + eosina. E para a detecção histoquímica de glicoconjugados utilizou-se as técnicas de P.A.S., P.A.S + amilase salivar, P.A.S. + acetilação, P.A.S. + acetilação reversível, alcian Blue (AB) pH 2,5 + metilação, AB pH 2,5 + metilação reversível, AB pH 2,5 e AB pH 0,5. Observou-se aumento na secreção de muco e na quantidade de células mucosas do epitélio branquial, além de diferenças na reatividade histoquímica das células mucosas do GE comparados ao GC, sugerindo uma resposta adaptativa desses animais ao novo ambiente. (AU)

Fluorine is an element much used by man and easily found in nature. Some studies have been carried out on the toxicity of fluorine and its cumulative effect on animal tissues. Sodium fluoride is described as being used in controlling the host of schistosomiasis (Biomphalaria glabrata). With a view to preserve the aquatic environment, it is proposed to verify the effect of sodium fluoride on fish (Poecilia vivipara). Ten fishes were divided into two groups. The first group was exposed to freshwater with sodium fluoride with a concentration of 5 ppm for a period of 21 days; the second group was exposed to freshwater. After 21 days the animals were sacrificed and their gills removed and processed according to histochemical/histologic methods and ultrastructural study. The gill leaflets were diaphanized in xylol. Histologic analyses using hematoxyline-eosin identified branchial epithelium and revealed mucous and chloride cells. The histochemical methods to detect glycoconjugate contents of mucous cells used: P.A.S, P.A.S. + salivar amylase; P.A.S. + acetylation ; P.A.S. + reversible acetylation; Alcian blue pH 2.5; Alcian blue pH 0.5; Alcian blue pH 2.5 + methylation; and Alcian blue pH 2.5 + reversible methylation. An increase in secretion of mucus and an alteration to the content of the granules were also observed, suggesting behavior changes of mucous type to enable these animals to adapt to the environment, thus altering the concentration of sodium fluoride. (AU)