Mixis in rotifers of the lineage 'Nevada', belonging to the Brachionus plicatilis species complex, under different feeding regimes |
| |
| Authors: | Venetia Kostopoulou Helen Miliou Yukiko Krontira & George Verriopoulos |
| |
| Institution: | Department of Zoology-Marine Biology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, Athens, Greece; Laboratory of Applied Hydrobiology, Faculty of Animal Production, Agricultural University of Athens, Athens, Greece |
| |
| Abstract: | A strain of Brachionus‘Nevada’, which belongs to the Brachionus plicatilis species complex, and is commonly found in European hatcheries, was investigated in terms of its mixis potential. Two feeding regimes used for mass culturing were employed. Rotifer populations were fed on phytoplankton (Tetraselmis suecica) and either baker's yeast, Saccharomyces cerevisiae (treatments A) or Culture Selco® (treatments B). In order to promote mixis, the salinity of the culture medium was reduced from 40 to 20 g L?1. Indeed, the rotifer populations of lower salinity (A 20, B 20) showed a twofold increase in mixis rates compared with those of higher salinity (A 40, B 40). In addition, treatment A 20 showed significantly higher levels of mixis (22.59±2.07%) compared with B 20 (16.56±1.46%). The opposite trend was observed for the parthenogenetic growth rates (A 20: 0.46±0.01; B 20: 0.62±0.01). It is thus concluded that Culture Selco leads to a higher abundance of amictic ovigerous females, whereas yeast supports a higher abundance of males and mictic females carrying resting eggs. The two types of feeding regimes can be used for different purposes in a hatchery. |
| |
| Keywords: | rotifera Brachionus hatchery mixis population structure |
|
|
