抄録
Annual changes in the urine properties of freely swimming carp were examined monthly in connection with changes in the natural environment. Urine flow and absolute excretion volume of inorganic ions (Na+, K+, Ca2+, Mg2+) and nitrogen compounds (ammo-nium, creatine, protein, urea, creatinine and uric acid) changed along with changes in water temperature. Urine osmolarity and Na+ concentration decreased markedly in May and June, but K+, creatine and protein increased significantly in May, October and Novem-ber-December, respectively. Also, it was assumed that the annual changes in these para-meters were dependent upon not only the water temperature but also several other factors, such as feeding habit and photoperiod.
