Ovicidal effect of essential oils of Lippia alba, Lippia sidoides and Lippia gracilis on the acanthocephalan Neoechinorhynchus buttnerae (Eoacanthocephala: Neoechinorhynchidae).

Acanthocephalosis in tambaqui Colossoma macropomum culture is a limiting factor for the production of the species, being the most recurrent, which makes it necessary to develop strategies to control parasitosis even in the early stages of parasite development. This study aimed to elucidate the morphological characteristics of eggs of the acanthocephalan Neoechinorhynchus buttnerae and the ovicidal effect of the essential oils of Lippia alba, Lippia sidoides, and Lippia gracilis. The parasites were collected from hosts naturally infected with N. buttnerae, and the eggs obtained from the female 'parasites' abdominal cavity were added to 12-well plates containing the essential oils at different dilutions. After the eggs (N = 300) were separated and measured (length and width) with the aid of an optical microscope coupled to a digital program, the viability of the treated eggs was monitored 24 h after treatments, L. gracilis essential oil was 100% effective at the highest concentration, whereas L. sidoides essential oil showed over 50% efficacy at 2 mg/ml, reaching 100% efficacy at all higher concentrations. Lippia. alba essential oil did not show satisfactory efficacy in preventing N. buttnerae egg hatching.

Distribution of the acanthocephalan Neoechinorhynchus buttnerae and semiquantitative analysis of histopathological damage in the intestine of tambaqui (Colossoma macropomum).

In this paper, we have described for the first time a semiquantitative method to evaluate histopathological damage, taking the degree of Neoechinorhynchus buttnerae attachment to the intestinal wall of the tambaqui (Colossoma macropomum), an important species in Brazilian aquaculture, into account. Twelve specimens of tambaqui were collected from a fish farm. Their bowels were removed and divided into seven morphologically distinct portions according to density and distribution of the parasite studies. Fragments from each fraction were histologically processed and analyzed. There was a clear preference on the part of N. buttnerae for the intermediate regions of the intestinal tube, where the highest densities were recorded. The intensity of damage to the host, estimated by calculating the Histopathological Alteration Index (HAI), showed severe and irreversible changes only where the parasite had its proboscis penetrated into the intestine wall.

Digestive tube of an herbivorous fish (Rhytiodus microlepis) from the Amazonian floodplain lakes: A morphological and histochemical study.

This study describes the morphology and histochemistry of the digestive tube of the herbivorous fish Rhytiodus microlepis, which is commonly found in the Amazonian floodplain lakes, Brazil. Thirty-eight fish were used in this study. The digestive tube was measured and dissected for anatomical description, and stained with (i) haematoxylin and eosin, for histological analyses; (ii) periodic acid-Schiff, for detected neutral mucins; and (iii) Alcian Blue (AB) pH 1.0 and 2.5 for acid and sulphated acid mucins. The oesophagus, with its secretory cells and taste buds, is adapted for lubrication of vegetable matter, resistance to friction and reception of stimuli. The stomach is U-shaped and rich in gastric glands, particularly in cardiac and fundic regions, which are adapted to receive large amounts of food, and promotes the digestion. The intestine comprises more than 70% of the digestive tube. All portions of the intestine, except the rectum, have the same pattern of mucosal folds, and the goblet cells reacted positively to all histochemical methods (PAS, AB 1.0 and 2.5), while rodlet cells reacted only to periodic acid-Schiff (PAS) staining. Neutral mucins and sulphated acid mucins predominated in the anterior portion of the intestine and a high concentration of carboxylated acid mucosubstances were present in the other portions. The rectum showed a strong reaction to all histochemical methods. The muscular layer of the intestine consists of three layers, which showed features presumably related to the rigid nature of the food. A simple squamous epithelium constitutes the serous layer over the entire length of the tube.

Morphology and Morphometry of the Ovaries and Uteri of the Amazonian Freshwater Stingrays (Potamotrygonidae: Elasmobranchii).

The reproductive biology of South American freshwater stingrays (family Potamotrygonidae) is still poorly studied compared to other marine species. In the present study, we examined the gross anatomy and histology of six species of potamotrygonids from the Amazon basin and described the structural asymmetry of the ovaries and their relationship between ovarian and uterine fecundities. Stereological techniques were used to quantify the volume of ovarian and epigonal organ tissue associated with the left and right sides of the Potamotrygon wallacei, a recently described species, locally known as the cururu ray. This species presented ovarian asymmetry; the left epigonal organ-ovary complex was 55 times larger than the right side. The right side was composed of, volumetrically, 7.3% ovarian tissue and 92.7% epigonal organ tissue whereas the left side was 51.2% of ovarian tissue and 48.8% epigonal organ tissue. In all species, six types of follicles were identified in both right and left ovaries. Uteri were symmetrical and the fecundity ratio between the right and left sides was 0.9:1.1, respectively. Despite the volumetric difference of ovarian tissue between the two sides, the uterine fecundity shows that both ovaries are functional and that ovarian fecundity alone is not an accurate measure to determine the reproductive potential of freshwater stingrays. Anat Rec, 300:265-276, 2017. © 2016 Wiley Periodicals, Inc.