Browsing by Author "Barany, Andre"
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- Aflatoxicosis Dysregulates the Physiological Responses to Crowding Densities in the Marine Teleost Gilthead Seabream (Sparus aurata)Publication . Barany, Andre; Fuentes, Juan; Martínez-Rodríguez, Gonzalo; Mancera, Juan MiguelSeveral studies in fish have shown that aflatoxin B1 (AFB1) causes a disparity of speciesdependent physiological disorders without compromising survival. We studied the effect of dietary administration of AFB1 (2 mg AFB1 kg−1 diet) in gilthead seabream (Sparus aurata) juveniles in combination with a challenge by stocking density (4 vs. 40 g L−1 ). The experimental period duration was ten days, and the diet with AFB1 was administered to the fish for 85 days prior to the stocking density challenge. Our results indicated an alteration in the carbohydrate and lipid metabolites mobilization in the AFB1 fed group, which was intensified at high stocking density (HSD). The CT group at HSD increased plasma cortisol levels, as expected, whereas the AFB1-HSD group did not. The star mRNA expression, an enzyme involved in cortisol synthesis in the head kidney, presented a ninefold increase in the AFB1 group at low stocking density (LSD) compared to the CT-LSD group. Adenohypophyseal gh mRNA expression increased in the AFB1-HSD but not in the CT-HSD group. Overall, these results confirmed that chronic AFB1 dietary exposure alters the adequate endocrinological physiological cascade response in S. aurata, compromising the expected stress response to an additional stressor, such as overcrowding.
- Dysregulation of intestinal physiology by Aflatoxicosis in the Gilthead Seabream (Sparus aurata)Publication . Barany, Andre; Oliva, Milagrosa; Gregorio, Silvia; Martínez-Rodríguez, Gonzalo; Mancera, Juan Miguel; Fuentes, JuanAflatoxin B1 (AFB1) is a mycotoxin often present in food. This study aimed to understand the physiological effects of AFB1 on the seabream (Sparus aurata) gastrointestinal system. In a first in vitro approach, we investigated ion transport using the short-circuit current (Isc) technique in Ussing chambers in the anterior intestine (AI). Application of apical/ luminal AFB1 concentrations of 8 and 16μM to healthy tissues was without effect on tissue transepithelial electrical resistance (TER), and apparent tissue permeability (Papp) was measured using fluorescein FITC (4 kD). However, it resulted in dose-related effects on Isc. In a second approach, seabream juveniles fed with different AFB1 concentrations (1 and 2mg AFB1 kg−1 fish feed) for 85days showed significantly reduced gill Na+ /K+-ATPase (NKA) and H+-ATPase (HA) activities in the posterior intestine (PI). Moreover, dietary AFB1 modified Isc in the AI and PI, significantly affecting TER in the AI. To understand this effect on TER, we analyzed the expression of nine claudins and three occludins as markers of intestinal architecture and permeability using qPCR. Around 80% of the genes presented significantly different relative mRNA expression between AI and PI and had concomitant sensitivity to dietary AFB1. Based on the results of our in vitro, in vivo, and molecular approaches, we conclude that the effects of dietary AFB1 in the gastrointestinal system are at the base of the previously reported growth impairment caused by AFB1 in fish.