Izuru Kakuta

Physiological response of carp, Cyprinus carpio, exposed to raw sewage containing fish processing wastewater

Physiological changes of carp exposed to raw sewage were investigated by the use of clinical examination methods. All carp exposed to raw sewage died within 6 h. On hour 48, 10, 40, and 90% of exposed carp survived in 60, 20, and 10% sewage, respectively. Carp exposed to 50 and 20% sewage increased ammonia, glucose, Mg, Cu, and Br, and decreased Fe and Zn in plasma. Even in 10% sewage, ammonia, glucose, and Br in plasma increased. Forty-eight hours of exposure to 50 and 20% sewage caused severe pathological changes in the gills. In the kidney, light abnormalities were observed at this time. When exposed to 50 and 20% sewage, atrioventricular conduction time and duration of electrical systole measured by electrocardiogram shortened briefly, and then extended gradually. In 50 and 20% sewage, heart rate and respiratory frequency increased briefly, and then decreased gradually. Cough reaction increased with the exposure.

Physiological response of the fish, Cyprinus carpio, to formalin exposure—I. Effects of formalin on urine flow, heart rate, respiration

1. Carp were exposed to 280 ppm formalin. Haematocrit and plasma glucose and lactic acid increased. In moribund fish, blood pH was remarkably lower and plasma protein increased. 2. When exposed to formalin, heart rate (HR) and respiration increased briefly, and then decreased. 3. Some fish increased urine flow (UF) immediately and maintained higher values for a while, followed by gradual decrease, and others decreased UF consistently. UF stopped at 30 min or longer prior to fish death. Urine osmotic pressure was higher at the 1st to 2nd hour and immediately before UF stopped. 4. The relationship between UF, HR and respiration was also discussed.

Renal response to hypoxia in carp, Cyprinus carpio: Changes in glomerular filtration rate, urine and blood properties and plasma catecholamines of carp exposed to hypoxic conditions

Abstract 1. 1. Changes in glomerular nitration rate (GFR), urine and blood properties and plasma catecholamines of carp were investigated during and following hypoxia. 2. 2. GFR and urine flow decreased with increased urinary concentrations of bio-components, except protein, in the course of hypoxia. 3. 3. Decreases in blood pH, and increases in haematocrit value and plasma K + , Ca 2+ , Mg 2+ , inorganic phosphate (P i ), ammonia, lactic acid and catecholamines (CAs) were observed as hypoxia progressed. 4. 4. Increased GFR and urine flow, and higher values for urinary components, except protein, compared with those of the control were found in the initial post-stress stage. 5. 5. The possible significance of increased plasma CAs in relation to changes in renal function in hypoxic carp is discussed.

Radioprotection of mice by lactoferrin against irradiation with sublethal X-rays

The influence of a host defense protein, lactoferrin (LF), contained in exocrine secretions such as milk, on radiation disorder was investigated. A total of 25 C3H/He mice in each of two groups were maintained with 0.1% LF-added and LF-free diets, respectively, for one month. The mice were then treated with single whole-body X-ray irradiation at a sublethal dose (6.8 Gy), and the survival rate after irradiation was investigated. The survival rate at 30 d after irradiation was relatively higher in the LF group than in the control group (LF-free), (85 and 62%, respectively). The body weight 15 d after X-ray irradiation was also significantly greater in the LF group than in the control group. The hemoglobin level and hematocrit value were higher in the LF group at 5 d before X-ray irradiation. Another 52 mice underwent whole-body X-ray irradiation at the sublethal dose (6.8 Gy), and then LF was intraperitoneally injected once at 4 mg/animal to half of them. The survival rate in LF-treated mice 30 d after irradiation was 92%, significantly higher than in mice treated with saline (50%) (P = 0.0012). In addition, LF showed hydroxyl radical scavenger activity in vitro. These findings suggest that LF may inhibit radiation damage.

Changes of iron content in eels (Anguilla japonica) infected with atypical Aeromonas salmonicida

Abstract 1. Hb, MCHC, Na, Ca, Mg and Cu in plasma decreased with atypical Aeromonas salmonicida infection. Whilst plasma K and NPN increased. 2. Plasma Fe decreased markedly with infection. No statistically significant change in UIBC was found, though moribund eels showed slightly lower values compared to that of the control. The rate of decrease in TIBC is similar to that in most elements in plasma. 3. Fe content in most tissues decreased with infection. It increased in the gills and head muscle (infection site). No significant change was found in the intestine. 4. Water content in various tissues increased with infection.

Blood changes in japanese eels, Anguilla japonica, experimentally infected with typical or atypicalAeromonas salmonicida

Abstract 1. 1. Changes in the blood and in the rate of oxygen consumption of Japanese eels injected intramuscularly in the head with a lethal dose of typical or atypical Aeromonas salmonicida at 20°C were investigated. 2. 2. Eels infected with the bacteria became moribund within 4 to 6 days, and then died within 1 day. 3. 3. The O2 consumption rate and blood parameters changed markedly with infections. The responses of hosts to infection by the two kinds of bacteria differed with regard to the following four points: blood pH, plasma Cl−, lactic acid, and the numbers of granulocytes and lymphocytes. 4. 4. The responses of eels infected with atypical A. salmonicida were larger and more rapid than those of eels infected with typical A. salmonicida.

Responses of the blenny Istiblennius enosimae exposed to asphyxic environments—1. Effects on heart rate and urine flow

Abstract 1. 1. Changes in heart rate (HR) and urine flow (UF) of blenny Istiblennius enosimae were investigated (i) under resting conditions, and (ii) during and following exposure to air or deoxygenated water. 2. 2. HR and UF showed significant diel rhythms. 3. 3. When fish were exposed to the air, HR decreased immediately to about 50%, and then returned to 70–80% of those in the control. As the fish were re-immersed in water, HR recovered immediately. 4. 4. When fish were exposed to deoxygenated water, HR decreased with progressive hypoxia. As normal oxygen level was recovered, H R increased markedly and reached higher values than those of the control for 60 min and longer. 5. 5. When fish were exposed to the air or deoxygenated water, UF decreased markedly and excretion of urine stopped within 30 min after the exposure. As normal oxygen level was recovered, UF reached levels about those of the control within 30 min. 6. 6. The relationship between HR and UF is discussed.