The study describes the morphological changes associated with parasitism by the intestinal acanthocephalan Neoechinorhynchus buttnerae in tambaqui juveniles Colossoma macropomum farmed in an excavated nursery, in Manaus (Amazon) in September 2013. After fish biometrics, analysis of macroscopic changes in morphology and counting of parasites, bowel fragments were fixed and submitted to histological and histochemical processing. All fish analyzed had acanthocephalans in the intestine; intestinal loops were milky white in color, with the presence of nodules with heavy parasitism. The changes in tissues that form the intestine varied according to the arrangement of the parasites: either free in the intestinal lumen or fixed by the proboscis on the organ wall. In the first case, the changes found were flaking, abrasion, compression, hypertrophy of goblet cells and disappearance of the villi on the mucosa, leukocytic cell infiltration in the submucosa, and muscle layer thickening. In the second case, in addition to these, other changes were observed as metaplasia in muscle tissue with its replacement by a loose connective tissue with severe leukocytic infiltration, edema in blood vessels, and necrotic foci. The histochemical analysis revealed that positive Alcian Blue mucosal cells (pH 2.5) were more expressive in parasitized intestines than in intestines not parasitized by N. buttnerae.

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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.

The present study investigated inhibition of pancreatic lipase and metabolic effects of high caloric diet in rats. The Passiflora nitida hydroethanol leaf extract (PNE) was used in in vitro assays or administered to rats to study dyslipidemia. Inhibition of lipase in vitro was studied by a spectrophotometric assay using orlistat as the positive control. The effects of PNE on reduction of postprandial triglyceride were studied by oral fat-overloading in rats. Metabolic alterations were induced using the cafeteria diet and 4 weeks post-treatment with PNE or orlistat and blood samples were collected and biochemical analyses were performed. Liver and retroperitoneal fat tissues were obtained to analyze weight and steatosis. IC50 (lg/mL) values for pancreatic lipase inhibition were 21.2 ± 0.8 and 0.1 ± 0.01 for PNE and orlistat, respectively. Oral administration of lipid emulsion resulted in postprandial hypertriglyceridemia at 3 h postadministration and when rats were then administered PNE and orlistat there was decreased of triglyceride levels by 15 % compared to control. Although the energy consumption by the cafeteria diet had been higher, there was no significant weight gain observed in the study groups. The cafeteria diet resulted in a significant increase of weight in the retroperitoneal fat and hypertriglyceridemia levels that could be significantly reduced by PNE and orlistat treatment. We hypothesized that PNE administration prevented the hypertriglyceridemia in rats with a high caloric diet, possibly owing to reduction of lipid absorption and pancreatic lipase inhibition.

The objective of the present study was to describe the histology and histochemistry of the mucosal layer of the digestive tube of Piaractus brachypomus, and the histopathology associated with parasitism by Neoechinorhynchus sp. The digestive tube of P. brachypomus consists of three macroscopically distinct portions: short, rectilinear and elastic‐walled ooesophagus, J‐shaped siphon stomach and a long intestine with rectilinear and curved portions, defined by patterns of villi as foregut, midgut, and hindgut. Histological and histochemical differences were observed in the mucosal layers of the different digestive tube regions, such as intense production of neutral and acidic mucous substances in the pseudostratified mucosal epithelium of the oesophagus; positive periodic acid Schiff reagent (PAS)reactions at the apex of the columnar epithelial cells of the stomach and increased intensity of histochemical reactions in the hindgut region. Neoechinorhynchus sp. was present in 85.7% of specimens examined, with a mean intensity of 7.4 ± 6.2 (±) and abundance of 6.33. Good health of the fish indicated by high relative condition factor values ( Kn) and occurrence of only mild to moderate alteration in the mucosal layer indicated that Neoechinorhynchus sp. exhibits low pathogenicity towards P. brachypomus hosts in farming environments, with low levels of infection.

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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.