Time filter

Source Type

Fyllingsdalen, Norway

Lie K.K.,National Institute of Nutrition And Seafood Research | Kvalheim K.,National Institute of Nutrition And Seafood Research | Rasinger J.D.,National Institute of Nutrition And Seafood Research | Harboe T.,Norwegian Institute of Marine Research | And 3 more authors.
Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology | Year: 2016

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). First-feeding larvae were fed enriched rotifers from start-feeding until 29days post hatch (dph). Larvae in four tanks were fed one of the following diets: control (EPA/ARA ratio: 15.8, 0.9μg VA g-1), control+VA (EPA/ARA ratio: 15.8, 7.8μg VA g-1), High ARA (EPA/ARA ratio: 0.9, 1.5μg VA g-1) or High ARA+VA (EPA/ARA ratio: 0.9, 12.0μg VA g-1). Larvae fed High ARA+VA were shorter at 29dph compared to the other groups and had significantly less mineralized bones when comparing larvae of similar size, showing interaction effects between VA and ARA. Although transcriptomic analysis did not reveal any interaction effects, a higher number of genes were differentially expressed in the high ARA fed larvae compared to control+VA fed larvae. Furthermore, bglap1, bglap2 and col10a1 were all down-regulated in larvae fed High ARA-diets and to a greater extent than larvae fed VA supplemented diet, indicating an additive effect on mineralization. In conclusion, this study showed that the dietary increase in ARA and VA altered the skeletal metabolism during larval 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. © 2015. Source

Penglase S.,University of Bergen | Penglase S.,National Institute of Nutrition And Seafood Research | Hamre K.,National Institute of Nutrition And Seafood Research | Olsvik P.A.,National Institute of Nutrition And Seafood Research | And 3 more authors.
Aquaculture Research | Year: 2015

It currently remains unclear if rotifers contain sufficient mineral levels to meet larval fish requirements. In this study, rotifers were enriched with a commercial enrichment (control), or with additional iodine, iodine and copper, or iodine, copper and manganese, and the effects of feeding these rotifers to Atlantic cod (Gadus morhua) larvae from 3 to 18 days post hatch were investigated. Rotifer enrichment with minerals was successful, but Mn enrichment also increased rotifer zinc levels. No differences were observed between treatments in larval growth or survival, or in the mRNA levels in the majority of the redox system genes analysed. Only Zn levels increased in cod larvae in response to mineral enrichment of rotifers. Apart from Zn, little evidence was found to suggest that cod larvae require increased concentrations above the control rotifer levels of the essential elements studied here. © 2013 John Wiley & Sons Ltd. Source

Nordgreen A.,National Institute of Nutrition And Seafood Research | Nordgreen A.,Norsildmel AS | Penglase S.,National Institute of Nutrition And Seafood Research | Penglase S.,University of Bergen | Hamre K.,National Institute of Nutrition And Seafood Research
Aquaculture | Year: 2013

Rotifers are a common first feeding diet for rearing marine fish larvae. However, the levels of Mn, Cu, Zn, Se and iodine found in rotifers are low and may be insufficient to meet larval fish requirements. This study investigates increasing the concentration of Mn, Cu, Zn, Se and iodine simultaneously in rotifers (Brachionus plicatilis) in both short term enrichments (3. h) or during batch cultures (6. days), using either organically bound or inorganic mineral sources. This study demonstrates that rotifers can simultaneously be produced with Mn, Cu, Zn and Se concentrations up to and higher than the known requirements of fish, while increasing the level of iodine in rotifers was ineffective at the concentrations tested. To produce rotifers with copepod levels of Mn, Cu, Zn and Se, only 6% of a commercial rotifer enrichment diet had to be replaced with organically bound minerals, leaving a large percentage of the rotifer diet free to deliver other important nutrients such as lipid and proteins. Rotifers enriched to copepod mineral levels and stored for 18. h retained 75-110% of their Se, Zn and Mn and 50% of their Cu. Overall, increasing rotifer mineral levels appears to be most effective when the mineral is available in an insoluble and hence ingestible form. © 2012 Elsevier B.V. Source

Penglase S.,National Institute of Nutrition And Seafood Research | Penglase S.,University of Bergen | Harboe T.,Norwegian Institute of Marine Research | Saele O.,National Institute of Nutrition And Seafood Research | And 4 more authors.
PeerJ | Year: 2013

Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I), at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua) were fed rotifers enriched to intermediate (26 mg I kg-1 dry weight; MI group) or copepod (129 mg I kg-1 DW; HI group) I levels and compared to cod larvae fed control rotifers (0.6 mg I kg-1 DW). Larval I concentrations were increased by 3 (MI) and 7 (HI) fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg-1 DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg-1 DW. © 2013 Penglase et al. Source

Discover hidden collaborations