EFFECTS OF TEMPERATURE AND METALS (ZINC AND CADMIUM) IN EMBRYONIC STAGE OF Anabas Testudineus: AN ALTERNATIVE FRESHWATER FISH EMBRYO TEST IN THE SOUTHEAST ASIA REGION

The fish embryo acute toxicity test (FET) was proposed as a promising alternative to the general practice of fish acute toxicity test (FAT) on living animals. To date, the available information on freshwater fish embryos in Southeast Asia is limited. Hence, this study aims to present preliminary data on the single and combined exposure effects of temperature and metals, including zinc and cadmium, on the embryonic development of Anabas testudineus. Over 80% of the embryos died after 10 hour post-fertilization (hpf) in all cadmium treatments, whereas the same effect was only observed in 49.6 and 146 mg/L of zinc treatment. The optimum temperature for rearing the embryos ranged from 27 to 34°C, with a survival rate greater than 90% was recorded. The combined test of zinc + cadmium showed the additive effect with approximately 80% mortality rate at 12 hpf, while the combination of temperature and cadmium had increased the mortality rate up to 100% at 16 hpf. The temperature was found to elevate the cadmium uptake in the embryos and magnified the concentration higher than the concentration in water.