The Marine Fungi Rhodotorula sp. (Strain CNYC4007) as a Potential Feed Source for Fish Larvae Nutrition

Abstract

Fish oil is used in the production of feed for cultured fish owing to its high polyunsaturated fatty acid content (PUFA). The over-exploitation of fisheries and events like “El Niño” are reducing the fish oil supply. Some marine microorganisms are considered potentially as alternative fatty acid sources. This study assesses a strain of Rhodotorula sp. (strain CNYC4007; 27% docosahexaenoic acid (DHA) of total fatty acids), as feed for fish larvae. The total length and ribonucleic acid (RNA)/deoxyribonucleic acid (DNA) ratio of Danio rerio larvae was determined at first feeding at six and 12 days old (post-yolk absorption larvae). Larvae fed with microencapsulated Rhodotorula sp. CNYC4007 had a significantly higher RNA/DNA ratio than control group (C1). At six days post-yolk absorption group, the RNA/DNA ratio of larvae fed with Rhodotorula sp. bioencapsulated in Brachionus sp. was significantly higher than control group fed with a commercial diet high in DHA (C2-DHA). Finally, at 12 days post-yolk absorption, the RNA/DNA ratio was significantly higher in larvae fed with Rhodotorula sp. CNYC4007 and C2-DHA (both bioencapsulated in Artemia sp. nauplii) than in control group (C1). These results suggest that Rhodotorula sp. CNYC4007 can be an alternative source of DHA for feeding fish at larval stage, providing a sustainable source of fatty acids.

Rhodotorula Strains Isolated from Seawater That Can Biotransform Raw Glycerol into Docosahexaenoic Acid (DHA) and Carotenoids for Animal Nutrition

“…In particular, the NCYC4007 yeast strain, characterized at the molecular level as a Rhodotorula strain, has been highlighted for its high production of DHA and carotenoids (23% and 11% dried weight, respectively) when the commercial Sabouraud medium (SM) was used [9]. This strain has been successfully used for fish larvae nutrition [10]. Additionally, in SM, a marine yeast from the Southern Austral marine ecosystem of Chile (strain NCYC1146), characterized as a high producer of carotenoids, was isolated.…”