AbstractFish were kept in non‐toxic water or at 0.5, 0.25 and 0.125 of the LC50,96hof the ten‐side or insecticide for 24 h and fed with toxified and non‐toxified feed. Toxified feed in normal water resulted in a maximum feed intake, while normal feed in toxified water resulted in a minimum one. In each case, the feed intake was lower compared with the control, and the feed intake was inversely proportional to the toxicant concentration. In a simple respirometer the oxygen consumption in mg · kg−1· h−1was tested for 1, 2, 4, 6, 8, 10, 12, 24, 36, 48, 60, 72, 84 and 96 h of exposure to 1.5, 1.0 and 0.5 of the LC50,96hof both substances. It was a flow device which was closed only for measurement for one hour. 1.5 LC50Aldrin causes a continuous reduction of respiration until death. The same effect occurred withCl. batrachusfor 1.5 LC50of the tenside, whereas withC. mrigaladeath was caused by a pronounced increase of respiration. In all other cases, after a phase of sensitization for 4 … 8 h respiration increased considerably to more than 300 of the control, which was followed after 12 … 24 h by acclimatization to normal res
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