Environmental effects on the oxygen consumption rate in juvenile Epinephelus fuscoguttatus (Forsskal, 1775).

This study was designed to optimize the culture conditions of juvenile Epinephelus fuscoguttatus (Forsskål, 1775) under laboratory conditions. To this effect, the rate of oxygen consumption was monitored as an index of stress under different temperature, salinity, pH, photoperiod, and urea concentrations. The result obtained after 12 h of exposure suggests the preference of the juvenile E. fuscoguttatus to a temperature range of 15-25 °C and salinity of 30 ppt. Based on this study, temperature was found to be the most lethal as 100% mortality was observed after 6 h in fish exposure to temperatures above the optimal (≥ 30 °C). However, the oxygen consumption rate was similar under the different pH, photoperiod, and urea concentration tested. It was concluded that water temperature was most critical in terms of respiration physiology of the juvenile E. fuscoguttatus given the range and levels of environmental factors tested in this study.

Is hypercalcemic diet a possible antidote to oral contraceptive-induced hypertension?

Administration of oral contraceptive (OC) has been associated with body fluid retention and in high doses over a long period, promotes hypertension. This present investigation tests the hypothesis that the dietary calcium supplementation increases salt and water excretion in OC (norgestre/ethinylestradiol) treated 32 female albino rats randomly distributed into four (1-4) groups of 8 rats each: Control, OC-treated, OC-treated+ Calcium diet fed and Calcium diet fed only respectively. OC was administered to the appropriate groups by gavage. Experimental diet contained 2.5% calcium supplement. Plasma and urinary [Na+] [K+] were evaluated after 8 weeks of experimentation by flame photometry and plasma [Ca2+] by colorimetric method. OC-treatment induced a significant fall in urinary [Na+]. Water excretion was significantly reduced in these animals (control, 3.1±0.56 Vs OC-treated rats, 1.47±0.16). OC-treated rats had significantly higher plasma [K+] compared to control rats. Calcium supplementation induced increases in plasma [Na+], [K+] and augmented urinary Na+ excretion (OC-treated + Ca2+ diet Vs OC-treated only). Compared with the control rats, high Ca2+ diet fed rats exhibited significant increases in plasma [Na+] and [K+] accompanied by significant decreases in urinary H20 excretion. These results strongly suggest that high dietary Ca2+ supplementation increases salt and water excretion in OC-treated rats and potentially moderates fluid retention and blood pressure in these animals, and may be of clinical significance in OC-induced abnormal fluid retention and perhaps OC-induced hypertension.