Effect of Dietary Metal Exposure on the Locomotor Reactions and Food Consumption in Common Carp Cyprinus carpio (L.)

Abstract

The effects of dietary zinc, copper or mercury (9.8, 9.5 and 0.66 mg/kg wet weight of forage, respectively) on different aspects of fish feeding behavior in common carp were evaluated. The latency to leave the starting chamber after its front wall was raised (t₁) and latency to feed (latent time of feeding, t₂) as well as the amount of food consumed or ration (the quantity of eaten chironomid larvae for 3 min of observation) were registered. By the end of the experiment under the impact of Hg, the t₁ value increased by 20% and t₂ value increased 5.6 times. The amount of food consumed decreased by 38%. The latency to leave the starting chamber under the impact of metal significantly increased during 20–30 days, followed by decline. The dynamics of the feeding reaction rate under the impact of metal differed: the maximum changes in t₂ value are noted under the impact of Cu: they were increased in the 2nd and 5th decade (3.7 and 6.1 times, respectively). The amount of food consumed in the presence of Zn either increased or remained at the control group level, but under the action of Cu and Hg was in most cases lower (by 37% at the most).