カサゴの血液学的研究-I : 環境水の塩素量と血液水分量・比重・血清蛋白量および赤血球数との相互関係

概要

論文の詳細を見る
An experimental study on the influence of changes in chlorinity on the haematological characteristics of Sebastiscus marmoratus was carried out with the hope that these might reveal ecological factors controlling the distribution of these fish in the sea. Two males and females (Table 1) were hooked in the vicinity of Nagasaki on September 19, 1963 and were kept in circulating sea water in a plastic tank (80×51×100cm) from September 19 to November 19, and in a concrete tank (75×71×130cm) from November 20 to August 25, 1964. The pH values of water in the latter tank were maintained within a range of 7.70-7.85. The chlorinity of the water was increased or decreased by adding ordinary salt or fresh water. The chlorini-ties used and the periods of acclimation are shown in Table 2. The blood was withdrawn from the Cuvierian duct of each fish following an acclimation period of at least three days with a 0.5 - 0.7ml syringe. Heparin (0.2mg/ml) was added to prevent coagulation of the blood. To minimize differences in the blood elements dependant on the time of day, all samples were taken between 9 and 11 a.m. KURODAs micro-measurement method was used to determine the moisture content of blood. A copper sulphate solution ad-justed from 1.022 to 1.050 with intervals of 0.002 was used as a standard in ascertaining the specific gravity of blood. After the separation of sera with a hand centrifuge, measurements of the serum protein were carried out with a Hitachi refractometer. The number of nucleated erythrocytes was counted with a Bürker-Türk counting cell after dilution with Hayem solution. The chlorinity was determined by titration using the KNUDSENs method. Several species of shrimp caught by trawl in the neighboring waters were used as food throughout the course of study. In this way, chemical changes in the diet were minimal. 1. In the experiments with considerably lower (8.22-8.34‰) or higher (22.31-22.47‰) chlorinities than that in the natural habitat (17.60-17.72‰) of S. marmoratus, the entire body surface of each specimen was covered was covered by a transparent mucous film. This seemed to regulate the osmotic mechanism against extreme changes in salinity. Feeding activities and swimming movements were markedly decreased. Indeed, there was scarcely any movement at all. These chlorinity values, therefore, appear to indicate the approximate upper or lower limits of chlorinity tolerance for this species. 2. No correlation was observed between the moisture content of blood and changes in chlorinity (Table 3, Fig. 1) or between the fluctuation of the quantity of serum protein and the chlorinity (Table 3, Fig. 1). On the other hand, a very high positive correlation was found between the specific gravity of the blood and the chlorinity of the water (Table 3, Figs. 1 and 2). Thus the specific gravity of blood increased with increasing, or decreased with decreasing chlorinity in the water, but a negative correlation was clearly found between the specific gravi-ty and the moisture content of blood (Table 4, Fig. 3). Consequently, these relations may indicate that the chlorinity changes in the fishes habitat would cause physiological readjust-ment of the moisture content of blood. 3. When the fishes were kept in more or less saline water than that of their natural habitat, a positive correlation was found between the specific gravity and the serum protein of blood. The interrelation between the serum protein and the moisture content of blood was, however, negative with one exception (Table 4). 4. When S. marmoratus was not subjected to any change in the chlorinity of the water, i.e. they were kept in natural sea water, the correlation coefficients calculated for three blood elements were conspicuously higher than those obtained for specimens reared with the water of abnormal chlorinities (Table 5, Figs. 4 and 5).

著者

山下秀夫
西海区水産研究所

カサゴの血液学的研究-I : 環境水の塩素量と血液水分量・比重・血清蛋白量および赤血球数との相互関係

スポンサーリンク

概要

著者

関連論文

スポンサーリンク