Effect of gamma-aminobutyric acid and porcine growth hormone on survival of the euryhaline rotifers Brachionus plicatilis sp. complex preserved at low temperature

摘要

Gamma-aminobutyric acid (GABA) at 50?μg/ml and porcine growth hormone (GH) at 0.025?IU/ml were tested to see whether these chemicals would reduce the stress experienced by euryhaline rotifers Brachionus plicatilis species complex (L-, S- and SS-morphotypes) during low temperature (4–12°C) storage. Rotifers cultured at 25°C were transferred to 4–12°C for 10–30?days and transferred back to 25°C for recovery. GABA or GH were added to the rotifers at three different time points: 6?h before transfer from 25°C to low temperature (6h?), on day 7 after preservation at low temperature (7d+) and on the first day of recovery. For L-type rotifers, the GH treatment before the transfer to 4°C for 30?days was effective for better survival, while the GABA treatment was most effective for the S-type preserved at 10°C for 14?days. For the SS-type, the chemical treatments were not effective when the rotifers were preserved at 12°C for 14?days. After low temperature preservation, GABA treatments with the S- and SS-type rotifers just after their transfer to 25°C induced a relatively faster recovery of the rotifer population.