Twenty adult partridges Rhynchotus rufescens were used for morphologic and histological study. The materials destined to the morphologic study were collected and the lengths of the glandular stomach and of the muscular stomach were measured. For the histological study, fragments of the glandular stomach (gastric proventriculus, Ventriculus glandularis) and of the muscular stomach (gastric ventriculus, Ventriculus muscularis) were stained routinely with periodic acid-Schiff (PAS) and Masson’s trichrome stain. Glandular stomach is prolonged, with a fusiform format toward craniocaudalis and for the left. It presents a mean length of 3.20cm in the females and 3.65cm in the males. Gastric proventriculus is composed by several lobes and glands. The mucosa is formed by a simple cubic epithelium, which is much folded. Muscular stomach has the format of a biconvex lens, with 4.30cm and 4.35cm of mean length for the females and male, respectively. The mucosa is formed by folds lined by columnar cells and the mucus that forms the cuticula. There are crypts in the base of the folds. Closely, there is a lamina propria and a thick smooth muscle layer, which is placed according to the format of the organ. A dense portion of connective tissue constitutes the serosa, mixed by some smooth muscle cells.

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Twenty adult partridges Rhynchotus rufescens were used to study the morphology of the beak and the tongue. Lengths of the beak and of the tongue were evaluated, and histologic sections of the tongue were stained routinely with hematoxylin-eosin (HE), periodic acid-Schiff (PAS) and Masson’s trichrome stain, later analyzed and described. The beak of the partridge of both sexes are curved, flat, hard and with a sharp extremity, with mean length of 4.90cm for the females and 4,80 for the males. The tongue is characterized by a triangular format with mean length of 1cm for both sexes, and its extremity is presented as a sharp format. Organization of the tongue tissue presents a stratified squamous epithelium with filiform papillae in all surface, mucous glands with ducts that project to the epithelium surface and a hyaline cartilage in the whole length of the tongue, which lays on the skeletal musculature that is guided in several directions.

In vitro effect of the Melaleuca alternifolia, Lavandula angustifolia and Mentha piperita essential oils (EOs) against Ichthyophthirius multifiliis and in vivo effect of M. alternifolia for treating ichthyophthiriasis in one of the most important South American fish, Piaractus mesopotamicus (Holmberg), were evaluated. The in vitro test consisted of three EOs, each at concentrations of 57 μL L(-1) , 114 μL L (-1) , 227 μL L(-1) and 455 μL L (-1) , which were assessed once an hour for 4 h in microtitre plates (96 wells). The in vitro results demonstrated that all tested EOs showed a cytotoxic effect against I. multifiliis compared to control groups (P < 0.05). The in vivo treatment for white spot disease was performed in a bath for 2 h day(-1) for 5 days using the M. alternifolia EO (50 μL L (-1) ). In this study, 53.33% of the fish severely infected by I. multifiliis survived after the treatment with M. alternifolia (50 μL L (-1) ) and the parasitological analysis has shown an efficacy of nearly 100% in the skin and gills, while all the fish in the control group died. Furthermore, the potential positive effect of M. alternifolia EO against two emergent opportunistic bacteria in South America Edwardsiella tarda and Citrobacter freundii was discussed.

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This work presents the structure and ultrastructure of the interrenal gland and chromaffin cells, as well as the morphology of the head kidney of Brycon cephalus. The head kidney is composed of fused bilateral lobes located anterior to the swim bladder and ventrolateral to the spinal column. The parenchyma revealed lympho-haematopoietic tissue, melano-macrophage centres, interrenal gland and chromaffin cells. The interrenal gland consisted of cords or strands of cells grouped around the posterior cardinal vein and their branches. Chromaffin cells are found in small groups, closely associated with the interrenal gland and/or under the endothelium of the posterior cardinal vein. So far, the ultrastructural analysis has revealed only one interrenal cell type which contained abundant smooth endoplasmic reticulum and numerous mitochondria with tubulo-vesicular cristae, characteristic of steroid-producing cells. Two types of chromaffin cells were observed. The first type was characterized by the presence of vesicles with round, strongly electron-dense granules, which were eccentrically located. Such cells were interpreted as noradrenaline cells. Meanwhile, cells which contained smaller vesicles and electron-lucent granules, with a small halo separating the granule from the vesicular limiting membrane, were identified as adrenaline cells.

The morphological characteristics of the ventricular myocardium and of coronary vascularization were studied in three freshwater teleost species, Piaractus mesopotamicus, Colossoma macropomum and Clarias gariepinus (African catfish), by correlating their ventricular shapes and swimming habits. In Piaractus mesopotamicus and Colossoma macropomum, species with highly active swimming habits, the cardiac ventricle showed a pyramidal shape and a richly vascularized myocardium consisting of an outer compact layer and inner spongy layer. In Clarias gariepinus, a less active species, we observed a saccular ventricle with a mixed myocardium and coronary arteries, in contrast to the ventricular structure of other species described in the literature.

A paca (Cuniculus paca) é uma espécie de roedor da família Cuniculidae, encontrada na América do Sul, desde a Bacia do Rio Orinoco até o Paraguai. Apesar de amplamente estudada quanto aos aspectos morfológico e reprodutivo, ainda não há registros sobre a morfologia do aparelho reprodutor masculino dessa espécie. Assim, objetivou-se avaliar não só a anatomia macro e microscópica dos órgãos genitais externos dessa espécie, mas, também, sua topografia. Foram estudados os órgãos genitais externos de 10 pacas, machos, adultas; 5 espécimes, fixados em solução aquosa de formol a 10%, foram estudados macroscopicamente e de 5 espécimes foram coletados fragmentos do aparelho reprodutor, para análise microscópica. Os testículos apresentavam parênquima estruturado em túbulos seminíferos e o epitélio germinativo repousava sobre sua membrana basal. Esses órgãos estavam localizados na cavidade abdominal, no trajeto inguinal ou no interior do escroto. O pênis, fibroelástico, localizava-se na região púbica, em direção caudal. Sua glande, revestida por epitélio queratinizado, era recoberta pelo prepúcio e, abaixo deste, identificou-se uma estrutura delgada cartilagínea com bordas serreadas. Um par de esporões ósseos abrigava-se em um saco ventral à uretra, cuja mucosa era revestida por epitélio de transição. O ducto epididimário apresentava-se enovelado na cabeça, continha corpo e cauda, sendo a cabeça revestida por epitélio pseudoestratificado estereociliado, e a cauda por epitélio cúbico simples; desta originava-se o ducto deferente, revestido por epitélio estratificado colunar. Palavra-chave: Morfologia; Órgão reprodutor masculino; Paca Biotemas, 26 (4): 209-220, dezembro de 2013 ISSNe 2175