Nitrate Toxicity on Visceral Organs of Medaka Fish, Oryzias latipes: Aiming to Raise Fish from Egg to Egg in Space

Abstract

Histological survey was made to determine nitrate toxicity on the Medaka fish, Oryzias latipes. In order to investigate the effects of short-term exposure to nitrate, one-month-old Medaka fish was exposed to NaNO 3 at concentrations of 100 and 125 mg NO 3 -N l -1 for 96 hours. At the end of the exposure period, survival rate was found to be 30% and 10%, for the 100 and 125 mg NO 3 -N l -1 exposure concentrations, respectively. Histological examination of the organs showed that disruption of cell alignment was a common feature in the gills, intestinal ampulla, liver and kidney. A long-term exposure experiment was also carried out, whereby Medaka fish was exposed to NaNO 3 (100 and 125 mg NO 3 -N l -1 ) for three months from its egg stage. Eggs treated with NaNO 3 hatched within 10 days after fertilization. At the end of the exposure period, survival rate in the 100 and 125 mg NO 3 -N l -1 treatments were 40% and 30%, respectively. Fibrosis of the hepatic cells and curved spinal column were observed in the juveniles subjected to long-term nitrate exposure. The results of our experiments suggest that the high mortality resulting from short-term acute exposure to nitrate is caused by general dysfunction throughout the whole body. The chronic toxic effects attributed to nitrate, following long-term exposure, were likely to have resulted from nutrient deficiency caused by hepatic dysfunction.

Acute and chronic toxicity of nitrate to fat greenling (Hexagrammos otakii) juveniles

“…Common carp Cyprinus carpio exposed to 12 mg/L nitrate-N presented abrupt and sluggish swimming movements, with occasional jumping and hitting the walls (Iqbal et al, 2005). Shimura et al (2004) observed loss of appetite and lethargic behavior in juvenile medaka O. latipes exposed to 100 mg/L nitrate-N. Our results showed a significantly lower final weight and SGR in the high-nitrate 157.3 mg/L treatment. Significant reduction in weight or body size in response to a stressor may indicate that energy is being used in detoxification rather than growth.…”

“…Common carp Cyprinus carpio exposed to 12 mg/L nitrate‐N presented abrupt and sluggish swimming movements, with occasional jumping and hitting the walls (Iqbal et al, ). Shimura et al () observed loss of appetite and lethargic behavior in juvenile medaka O. latipes exposed to 100 mg/L nitrate‐N.…”

“…Other negative effects of nitrate on fishes include decreased reproductive maturation (Good & Davidson, 2016;Guillette & Edwards, 2005;Hamlin, 2006;Hamlin et al, 2008), abnormal skin color (Hamlin, 2006;McGurk, Landry, Tang, & Hanks, 2006;Rodrigues et al, 2011), and various markers of tissue-level damage. For example, Shimura, Ma, Ijiri, Nagaoka, and Uchiyama (2004) showed disruptions of cell alignment in gills, intestinal ampullae, liver, and kidney in medaka Oryzias latipes. Rodrigues et al (2011) observed lamellar fusion and telangiectasia in gills; hyperplasia of epithelium and mucus cells in esophagus; and glial cell proliferation, satellitosis, and enlarged perivascular spaces in the brain of cobia Rachycentron canadum.…”

Effects of simulated microgravity on the development of the swimbladder and buoyancy control in larval zebrafish (Danio rerio)

“…It is, therefore, not clear what the biological effects of changes in water quality were. Water quality seems to be seldom, if ever, monitored in space flights (Shimura et al, 2004). Our study is the first to attempt to examine water quality in ground‐based studies of SMG exposure on teleosts and suggests that such measures deserve more attention in the future.…”

Noninvasive assessment of nitrate-induced stress in koi Cyprinus carpio L. by faecal cortisol measurement

“…Decomposition demands large amounts of oxygen and produces large quantities of ammonia and NO 3 − (de Croux, Julieta & Loteste 2004). Municipal and industrial wastes are concentrated sources of nitrogen compounds that are, to a large extent, released directly into surface waters (Shimura, Ma, Ijiri, Nagaoka & Uchiyama 2004). Even if treated, this waste will represent a heavy water pollution load since secondary treatment removes less than half of the nitrogen (Jittawattanarat, Kostarelos & Khan 2007).…”