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# Influence of dietary astaxanthin on lipid and glucose metabolism in liver of rainbow trout

C.T. Kalinowski, M.S. Izquierdo, Mónica B. Betancor, Matthew Sprague, Laurence Larroquet, Vincent Veron, Stéphane Panserat, Stéphanie Fontagné-Dicharry

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## To cite this version:

C.T. Kalinowski, M.S. Izquierdo, Mónica B. Betancor, Matthew Sprague, Laurence Larroquet, et al. Influence of dietary astaxanthin on lipid and glucose metabolism in liver of rainbow trout. International Symposium of Fish Nutrition and Feeding, ISFNF, Jun 2022, Sorrento, Italy. hal-05076080

HAL Id: hal-05076080

https://hal.inrae.fr/hal-05076080v1

Submitted on 20 May 2025

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# SESSION 9 NUTRITION AND FISH HEALTH

## 056

### INFLUENCE OF DIETARY ASTAXANTHIN ON LIPID AND GLUCOSE METABOLISM IN LIVER OF RAINBOW TROUT

C.T. Kalinowski ¹, M.S. Izquierdo ¹, M.B. Betancor

³, M. Sprague ³, L. Larroquet ², V. Veron ², S.

Panserat ², S. Fontagné-Dicharry ²

¹Grupo de Investigación en Acuicultura (GIA), IUECOAQUA, Universidad de Las Palmas de Gran Canaria, Spain

²INRAE, Univ. Pau & Pays Adour, NUMEA, 64310, Saint-Pée-sur-Nivelle, France

³Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, FK9 4LA Stirling, Scotland, UK

The current study aimed to investigate the influence and underlying mechanisms of dietary astaxanthin (AX) on hepatic glucose and lipid metabolism in rainbow trout. For this purpose, two iso-nitrogenous, iso-lipidic, and iso-caloric diets were tested, for 85 days in rainbow trout, with a mean initial weight of 309g. The experimental diets differed only by the AX content: the control diet (CTRL) had no AX, and the S-ASTA diet was supplemented with 100 mg of synthetic AX per kilogram of feed. Rainbow trout fed on the S-ASTA diet showed a significantly decreased liver weight and hepatosomatic index, without significant differences in hepatic glycogen and lipid contents. However, hepatic neutral lipid content was significantly reduced in rainbow trout fed the S-ASTA diet, due to decreased triacylglycerol and diacylglycerol levels and increased phosphatidylcholine and phosphatidylethanolamine levels. The gene expression of adipose triglyceride lipase and hormone-sensitive lipase, involved in hepatic lipolysis, were also both significantly upregulated in rainbow trout fed the S-ASTA diet, as well as the gene expression of hepatic carnitine palmitoyltransferase1, linked to β-oxidation. A significantly higher expression of sterol regulatory element-binding proteins 2, and 1,2-diacylglycerol choline phosphotransferase found in fish fed the S-ASTA diet suggested the possible role of dietary AX in sterol and phospholipid synthesis. About glucose metabolism, the S-ASTA diet significantly upregulated the expression of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, two enzymes of the oxidative phase of the pentose phosphate pathway (ox-PPP) producing nicotinamide adenine dinucleotide phosphate that plays a fundamental role in the antioxidant system and synthetic steps. Overall results indicate that dietary AX has a hepatic hypolipidemic effect and enhances hepatic glucose utilization through the ox-PPP, which may explain the other dietary AX applications.

## 057

### OPTIMAL VITAMIN NUTRITION TO FOSTER SUSTAINABLE SALMONID AQUACULTURE

A. Dumas ², E. Santigosa ¹, V. To ², A. Liu ²

¹DSM Nutritional Products

²The Center for Aquaculture Technologies

Aquaculture is the fastest-growing animal industry worldwide and calls for sustainable and safe ingredients and additives to ensure the performance, health, and welfare of farmed fish. However, the new generation of aquafeeds that replaces marine ingredients with novel protein and alternative omega 3 sources is challenging the established requirements for minerals and vitamins. In addition, current farming conditions and genetic improvement indicate that basal requirements need to be reviewed to secure healthy fish production and minimize nutrient losses.

Recent research and industry practices reveal recommended levels of certain vitamins and other micronutrients must be revised to not only enhance survival, but also maximize growth, promote health, and welfare, and improve food quality. Our studies show that high inclusion levels of certain fat-soluble vitamins (e.g. vitamin E up to 600 mg/Kg feed) or their metabolites (vitamin D, between 0.0625 and 0.2 mg 25OHD3/Kg feed) have positive impacts on growth, immunity, and shelf life of final product. Furthermore, optimal inclusion of vitamins C and B12 improved growth and increased relative abundance of lymphocytes and hemoglobin concentration in trout fed levels up to 1000 mg/kg and 0.25 mg/Kg, respectively. Similarly, other micronutrients such as choline can be included at doses exceeding minimum requirements to ameliorate gut health over the production cycle. The use of vitamin premixes and their synergies, together with some research gaps in vitamin nutrition will be highlighted to further strengthen and align future research in this field.