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Calcifediol source of vitamin D improve growth performance in gilthead seabream juveniles

Gran Canaria, Spain, 4 August 2025 | This study represents the first evidence of calcifediol use in Mediterranean marine species

Doradas juveniles estanque

Researchers from the University of Las Palmas de Gran Canaria (Spain) have demonstrated that calcifediol, a vitamin D metabolite widely used in livestock, can enhance growth performance and nutrient retention in juvenile gilthead seabream (Sparus aurata). The findings, published in Aquaculture Reports, represent the first evidence of calcifediol use in Mediterranean marine species.

 

Gilthead seabream, like many marine species, has a limited capacity to synthesise vitamin D naturally, particularly in indoor or intensive farming systems where exposure to sunlight is minimal. As a result, the species must obtain this vitamin directly from the diet, which is essential for bone development, calcium and phosphorus metabolism, and overall growth, and whose availability and biological effectiveness depend on its chemical form.

Traditionally, aquafeeds include vitamin D3 (cholecalciferol), which requires two metabolic conversions before it becomes fully active: first in the liver to calcifediol (25-hydroxycholecalciferol) and then in the kidney to calcitriol (1,25-dihydroxycholecalciferol). If these conversions are slow or inefficient, growth and bone mineralisation may be suboptimal.

In short, the efficiency and safety of the vitamin D source directly affect juvenile seabream health, skeletal formation, and production performance, especially in the early stages of culture when fish are most vulnerable to deformities and growth delays.

Feeding Trial and Results

The study, conducted in collaboration with Huvepharma NV (Belgium), tested five dietary levels of calcifediol (<2.0, 99.7, 167.4, 298.6 and 825.4 ppb) in 600 seabream juveniles (12 g) over a 15-week feeding trial. All diets also included 3,000 IU/kg of vitamin D3 to provide a baseline level of the nutrient.

The trial revealed that 99.7 ppb of calcifediol delivered the best overall performance, with the highest growth and most efficient feed conversion, reaching a total weight gain of 528.9%.

Intermediate doses of 99.7–167.4 ppb also enhanced vertebrae calcium content and improved the whole-body omega-3 to omega-6 ratio.

In contrast, high supplementation (≥298.6 ppb) resulted in reduced growth, lower vertebral calcium, and shorter mid-intestine folds, suggesting a potential toxic effect at excessive doses. Across all treatments, the prevalence of skeletal anomalies remained between 25.9% and 33%, with no significant differences.

Histological analysis added further insight. Diets containing 99.7–167.4 ppb increased the length of mid-intestine folds, while 167.4 ppb boosted the density of goblet cells in the anterior intestine by 50%, a change that may enhance mucosal protection and gut health.

 Fish receiving intermediate doses of 99.7 to 167.4 ppb also displayed improved vertebrae calcium content and a more favourable whole-body omega-3 to omega-6 ration.

In contrast, when calcifediol levels reached 298.6 ppb or higher, growth declined, vertebral calcium decreased, and mid-intestine folds became shorter, indicating that excessive supplementation may have a toxic effect. Across all treatments, the prevalence of skeletal anomalies remained between 25.9% and 33%, without significant differences.

Histological observations added another layer of insight: supplementation at 99.7-167.4 ppb increased the length of the mid-intestine folds, while 167.4 ppb notably raised the density of globet cells in the anterior intestine by 50%, a change that could enhance mucosal protection and intestinal health.

According to the authors, calcifediol shows promise as a more efficient alternative to vitamin D3 in aquafeeds, optimising growth and bone mineralisation at low doses. However, they caution that the margin between beneficial and excessive supplementation is narrow, requiring careful formulation in commercial feeds.

Reference:

Dominguez, D., Castro, P., Marmonier, M., Arana, D., Arriagada, P., & Montero, D. (2025).
Use of calcifediol in gilthead seabream (Sparus aurata): Effects on growth performance, biochemical composition, skeletal anomalies and histology.
Aquaculture Reports, 43, 103006. https://doi.org/10.1016/j.aqrep.2025.103006

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