ABSTRACT: Vitamin A and arachidonic acid altered the skeletal mineralization in Atlantic cod larvae (Gadus morhua) without any interactions on the transcriptional level
Project description:The main object of this study was to evaluate the impact of different levels of vitamin A (VA) and arachidonic acid (ARA) in relation to eicosapentaenoic acid (EPA) on mineralization and gene expression in Atlantic cod larvae (Gadus morhua). A two-way factorial design was used to identify possible interactions between the nutrients. First-feeding larvae were fed enriched rotifers from start-feeding until 29 days post hatch (dph). Larvae in four tanks were fed one of the following diets: control (EPA/ARA ratio: 15.8, 0.9 µg VA g-1 wet wt.), control+VA (EPA/ARA ratio: 15.8, 7.8 µg VA g-1 wet wt.), High ARA (EPA/ARA ratio: 0.9, 1.5 µg VA g-1 wet wt.) or High ARA +VA (EPA/ARA ratio: 0.9, 12.0 µg VA g-1 wet wt.). There was no difference in survival (33-40%) between the groups. Larvae fed High ARA+VA were shorter at 29 dph. The larvae fed High ARA+VA had significantly less mineralized bones, showing significant interaction effects between VA and ARA. Although transcriptomic analysis using a custom-made microarray did not reveal any interaction effects, it was found that high ARA diets altered the transcription of more genes than control +VA diets. Furthermore, blgap1 , blgap2 and col10a1 were all down-regulated in larvae fed High ARA-diets and to a lesser extent by Control +VA diet. Lower expression in the High ARA+VA diets compared to ARA and VA diets indicated an additive effect on mineralization. In conclusion, this study showed that the dietary increase in ARA and VA altered the skeletal metabolism during larval A. cod development, most likely through signaling pathways specific for each nutrient rather than an interaction. The present study also demonstrates that VA could affect the larval response to ARA, even within the accepted non-toxic/non-deficient range.
Project description:Lipid metabolism is essential in maintaining energy homeostasis in multicellular organisms. In vertebrates, the peroxisome proliferator-activated receptors (PPARs, NR1C) regulate the expression of many genes involved in these processes. Four Ppar subtypes from Atlantic cod (Gadus morhua) were recently cloned and characterized. However, the downstream regulatory role of Ppars in cod lipid metabolism is presently not well understood or described. Here we study the involvement of Atlantic cod Ppar subtypes in systemic regulation of lipid metabolism using the model agonists WY14,643, GW501516, and tetradecylthioacetic acid, employing a multiple omics approach after an in vivo exposure situation.
