The effect of using rotifers enriched with microscopic algae on growth indices, survival and quality of rainbow trout body (Oncorhynchus mykiss)

The aim of this study was to enrich the rotifer with microscopic algae as a feed in order to investigate their effects on growth indices and survival rates of rainbow trout larvae. For this purpose, Chlorella vulgaris and Scenedesmus quadricauda were used as foods, separately and together, for feeding the rotifer Brachionus plicatilis. In treatment 1, the larvae fed the enriched rotifers with chlorella, in treatment 2 fed the enriched rotifers with Scenedesmus algae and in treatment 3, fed the enriched rotifers with a combination of chlorella and Scenedesmus (50%). The control was performed using commercial feed. The density of algae cells per milliliter of water kept at 10 × 107 cells in each medium. In each experimental unite, a 60 liter of fish tank, 30 rainbow trout (Oncorhynchus mykiss) were stored. The mean (± SD) larvae weight reached to 409.66 ± 2.51 and 594.66 ± 4.93 mg on days 14 and 21 in the control group and the maximum weight was 694.33 ± 7.50 mg on day 21 in treatment 3. The specific growth, feed conversion ratio and protein efficiency and survival rates were also significantly different among treatments 1, 2 and 3 (P <0.05). The body composition analysis showed significant (P <0.05) differences in crude protein and crude fat indices in treatments 1 and 3 on day 21. The results of this experiment showed that the enriched rotifers with Chlorella and a combination of Chlorella and Scenedesmus could significantly improve the growth and survival indices in Larvae of Rain bow trout.