The Distribution of IgT mRNA+ Cells in the Gut of the Atlantic Salmon (Salmo salar L.).

The newly discovered IgT+ B cell is thought to play a dominant role in mucosal immunity, but limited studies have examined its distribution in fish species, hindering our understanding of its function. This study investigated IgT and poly Ig receptor (pIgR) mRNA+ cell distribution in Atlantic salmon (Salmo salar) gut using RNAscope in situ hybridization (ISH) and assessed the effects of vaccination. The pyloric caeca, mid-intestine (first and second parts), and posterior segment in two weight stages (Group 1: avg. 153 g, Group 2: avg. 1717 g) were examined in both vaccinated and unvaccinated fish. ISH revealed more IgT mRNA+ cells in the second part of the midgut compared to other intestinal segments, as well as a higher number of positive cells in Group 2 (older fish). In line with previous findings, intraperitoneal vaccination had no significant impact on the number of IgT+ transcripts. IgT mRNA+ cells were found mostly in the lamina propria and near capillaries, while pIgR was registered in both the lamina propria and mucosa. Interestingly, vaccinated fish presented adhesions and granulomatous tissue in the peritoneum, with both IgT and pIgR mRNA+ cells. Taken together, these results suggest that the distribution of IgT mRNA+ cells in the intestine of Atlantic salmon is region-specific and is not affected by intraperitoneal vaccination but varies with fish age.

Piloleiomyosarcoma in cats: Histological and immunohistochemical features.

This study describes the histomorphology and immunohistochemical profile of 9 cases of feline piloleiomyosarcoma. Cats ranged in age from 7 to 16 years (mean 10), and tumors were 7 to 24 mm in diameter (mean 15). Tumors were composed of fusiform cells that were haphazardly arranged or in variably sized interwoven bundles. Neoplastic cells had eosinophilic and fibrillar cytoplasm, and elongated blunt-ended nuclei. Entrapment of hair follicles and absence of vascular components support an origin from the smooth muscle cells of the arrector pili. Additional findings included bizarre nuclei and giant cells (7/9 cases), atypical mitoses (7/9 cases), ulceration (3/9 cases), and intratumoral necrosis (6/9 cases). Neoplastic cells expressed calponin, desmin, α-smooth muscle actin, and vimentin, but not CD18, CD31, cytokeratins, glial fibrillary acidic protein, neuron-specific enolase, Melan A, p63, or S-100 protein. Surgical excision was curative in 6/9 cases, with local recurrence in 2/9 cases and metastasis to local lymph nodes in 1/9 case. Clinical outcome was influenced by mitotic count, infiltration of subcutaneous tissue, and intensity of nuclear immunolabeling for p53.

Texture changes during chilled storage of wild and farmed blackspot seabream (Pagellus bogaraveo) fed different diets.

The impact of changes in dietary lipids and protein sources on texture was evaluated on farmed blackspot seabream (Pagellus bogaraveo) throughout 14 days of ice storage and compared with wild fish. A commercial diet formulated with a high proportion of lipids, and two diets formulated with an important reduction of lipid levels by 60% and adding either plant protein sources (LL diet) or fishmeal (LL + diet) were supplied during growth until commercial size was attained. In the wild fish, the raw fillet hardness was significantly higher than in farmed fish during the entire ice-storage period. In the farmed fish, an increase of muscle lipid accumulation and change of fiber density were responsible for the variations in texture in the raw fillet. The highest reduction was found in fish fed with diets LL+ and LL. The texture parameters studied on the cooked fillets showed no significant differences, neither attributable to the diets nor to the ice-storage period.

Histochemical localization of zinc in the retina cells of gilthead sea bream (sparus aurata) fed different presentations of zinc.

To describe the distribution of zinc in the retina of a representative marine fish species and to determine whether the intracellular deposition amount correlates with the presentation of the zinc included in the practical diets (organic, inorganic, encapsulated, fish meal, and Control diet), we examined the precise localization of endogenous zinc in the gilthead sea bream (Sparus aurata) retina by autometallography. As observed by light microscopy, reaction products were widely distributed throughout the retina, including the outer segments of photoreceptors, except in the nuclear layers. Differing from other species previously studied, zinc depositions were not different between the outer and inner retina, and the retinal ganglion cell layer showed reaction products with a characteristic disposition surrounding the neuronal soma. An additional finding in this species was the rich disposition around photoreceptors, so abundant that it outlines the shape of the rods and cones. With regards to the diet, the zinc organic formulation was able to produce a higher amount of precipitates, followed by fish meal and encapsulated zinc diets. The inorganic and the Control diet produced a basal zinc deposition in the same layers above mentioned although less evident and similar to that determined in other species fed with non-supplemented diets.