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Nitrite Disruption in Olfaction and Internal Physiology in Goldfish ( Carassius auratus )
Author(s) -
Martinez Melody,
Huertas Mar
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.813.17
Subject(s) - nitrite , carassius auratus , chemistry , olfactory epithelium , hemoglobin , gill , nose , biology , anatomy , biochemistry , nitrate , fishery , fish <actinopterygii> , receptor , organic chemistry
Freshwater ecosystems have experienced a dramatic increase of nitrogenous compounds as a result of farming and industrial activity. Nitrite accumulates by bacterial denitrification/nitrification in freshwater and saltwater ecosystems, reaching concentrations of 1 mM and 0.5 μM respectively. Exposure to high nitrite concentrations can disrupt the endocrine system and physiological processes such as ion homeostasis, respiratory, and cardiovascular activity. However, the accumulation of nitrite in different internal tissues and its effect on external sensitive organs, such as the olfactory epithelium, is unknown. This study aimed to determine the physiological effects of nitrite and its accumulation in several organs in goldfish ( Carassius auratus ). Goldfish were exposed to different nitrite treatments (0 mM, 0.3 mM, 1.0 mM, and 10 mM) for five days. Upon completion of experiment, brain, nose, liver, kidney, and gill samples were obtained for biological and histological analysis. Goldfish in two treatments (1.0 mM and 10 mM) experienced irreversible oxidation of hemoglobin known as metahemoglobemia, marked by browning of the blood and darker tissues. Biochemical analysis showed an increase of nitrite in brain, nose, liver, and gill tissues. Brain and nose tissues (240 ±0.004 μM and 260 ±0.002 μM, respectively) accumulated more nitrite than gill tissue (190 ±0.002 μM) in the lowest treatment (0.3 mM), and this trend continued as treatment concentrations increased. Preliminary statistical analysis demonstrated that both the brain and nose tissue accumulated >30% more nitrite than gill tissue in the 0.3 mM treatment. Histological analysis of the olfactory epithelium showed hyperplasia, an increase in cell size and number; furthermore, we observed an increase in the number of mucus cells and mucus production, collapse of columnar cells, and lamella constriction in both the 1.0 mM and 10 mM treatments. Histological analysis of gills showed lamella fusion and vascular congestion. Histological liver samples exhibited melanomacrophage aggregate, nucleus degeneration, and cytoplasmic vacuolation in 10 mM. Preliminary findings from electro‐olfactograms show that nitrite reduced the ability of a goldfish to detect odors at nitrite exposure as low as 0.1 mM. These results suggest that nitrite is accumulating faster in external sensory tissues than internal organs, affecting essential physiological processes such as olfactory food detection and possibly acting as a neurotoxin. Support or Funding Information Research support: Texas State University start‐up funding to Dr. Mar Huertas. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .