Nutritional enrichment of rotifer Brachionus plicatilis and its effect on clownfish larvae Amphiprion clarkii (Bennett, 1830)

The present study, evaluated the effect of enrichment of the rotifer Brachionus plicatilis with the microalga Nannochloroposis salina, amino acid derivative L-carnitine and commercially available S-presso (SELCO). The study also evaluated the effect of enriched rotifers in larval rearing of Amphiprion clarkii in terms of metamorphosis, pigmentation, growth and survival of larvae. Rotifer production increased by 43, 39 and 54% respectively in B. plicatilis enriched with different concentrations of L-carnitine at 1, 10 and 100 mg l(-1) on day 4 (p<0.001) in comparison with the control group maintained on algal diet alone. Total unsaturated fatty acid (PUFA, HUFA and n-3 fatty acids) and the ratios of n-3/n-6, DHA/EPA, EPA/AA were significantly higher (p<0.05) in the L-carnitine treated rotifers compared with the S-presso enriched as well N. salina enriched groups. Larvae of A. clarkii, fed with L-carnitine enriched rotifer achieved maximum growth of 56.92 +/- 0.2 mg; whereas, those fed S-presso treated rotifers attained only 48.74 +/- 1 mg. In L-carnitine enrichment; metamorphosis of clown fish larvae took only 10 days, while it took 11 days and 10 days respectively in S-presso and N. salina enrichment. In L-carnitine and S-presso enrichments, initial pigmentation of larvae was observed within first 3-4 days of culture, whereas it took 4-5 days in N. salina enrichment. L-carnitine enrichment resulted in the highest survival of 70%, followed by N. salina with 68% and S-presso enriched group with 52%. The results indicate that L-carnitine could be a recommendable enrichment for increasing rotifer production as well as for clown fish larval culture.