Vitamin E Requirement in Practical Feed for Farmed Atlantic Salmon (Salmo salar) During Smoltification and Its Long-Term Impact on Fish Welfare.
5 affiliations
- 1Research Group of Feed and Nutrition Institute of Marine Research Bergen 5005 Norway imr.no.
- 2Hamre Aquatic Nutrition Breiviken 8 Bergen 5042 Norway.
- 3Reproduction and Developmental Biology Group Institute of Marine Research Matre Research Station Matredal 5984 Norway imr.no.
- 4Nutrition and Feed Technology Department Norwegian Institute of Food, Fisheries and Aquaculture Research (Nofima) Bergen 5141 Norway nofima.no.
- 5Skretting Aquaculture Innovation P.O. Box 48 Stavanger 4001 Norway skretting.com.
Abstract
This study aimed to establish the vitamin E requirement for Atlantic salmon during smoltification and to evaluate its long-term implications for fish welfare. Using a regression design, seven diets with graded levels of α-tocopherol (aTOH) ranging from 38 to 710 mg/kg were tested in duplicate or triplicate tanks stocked with 110 Atlantic salmon (initial weight: 81 ± 2 g), respectively. After 11 weeks, 12 fish were sampled as freshwater smolts (FW-smolts), while the remaining fish were transferred to seawater and subjected to a challenge involving combined hypoxia and temperature stress before being sampled (seawater smolt [SW-smolt]). Additionally, 22 fish from each tank were transferred to a single sea cage and fed a common commercial diet for 5 months to assess the long-term impact of vitamin E nutrition during smoltification on key welfare indicators in post-smolt. No significant effects of dietary aTOH levels on growth performance were observed, but feed intake increased in FW-smolt fed up to 82 mg/kg. A high deposition of aTOH in liver tissue was observed in both FW- and SW-smolt fed more than 400 mg aTOH/kg. Malondialdehyde (MDA) levels in the liver decreased with aTOH supplementation with breakpoints at 457 mg/kg for FW-smolt and 99 mg/kg for SW-smolt, suggesting life-stage-specific differences in oxidative stress reduction. In SW-smolt, muscle astaxanthin levels increased linearly in response to dietary aTOH. Hematocrit and hemoglobin levels were unaffected in FW-smolt but displayed breakpoints in SW-smolt at 367 and 450 mg/kg, respectively. Welfare assessments revealed that fish fed 38 mg/kg during smoltification had a higher incidence of cataracts at the SW-smolt stage and complete vertebral fusion at the post-smolt stage. These findings suggest a minimum dietary aTOH requirement of 82 mg/kg to mitigate welfare issues, while tissue homeostasis, blood marks, and MDA suggest a practical requirement around 367-450 mg/kg.
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BibTeX
@article{wischhusen2026vitamin,
title = {{Vitamin E Requirement in Practical Feed for Farmed Atlantic Salmon (Salmo salar) During Smoltification and Its Long-Term Impact on Fish Welfare.}},
author = {Pauline Wischhusen and Kristin Hamre and Per Gunnar Fjelldal and Kaja H Skjærven and Sofie C Remø and Katerina Kousoulaki and Anne-Catrin Adam and Ingunn Stubhaug and Antony Jesu Prabhu Philip and Nini H Sissener},
journal = {Aquaculture nutrition},
year = {2026},
month = nov,
doi = {10.1155/anu/8100107},
url = {https://europepmc.org/article/MED/42968881},
note = {CC BY},
}
RIS
TY - JOUR
TI - Vitamin E Requirement in Practical Feed for Farmed Atlantic Salmon (Salmo salar) During Smoltification and Its Long-Term Impact on Fish Welfare.
AU - Pauline Wischhusen
AU - Kristin Hamre
AU - Per Gunnar Fjelldal
AU - Kaja H Skjærven
AU - Sofie C Remø
AU - Katerina Kousoulaki
AU - Anne-Catrin Adam
AU - Ingunn Stubhaug
AU - Antony Jesu Prabhu Philip
AU - Nini H Sissener
PY - 2026
DA - 2026/11/01
JO - Aquaculture nutrition
DO - 10.1155/anu/8100107
UR - https://europepmc.org/article/MED/42968881
AB - This study aimed to establish the vitamin E requirement for Atlantic salmon during smoltification and to evaluate its long-term implications for fish welfare. Using a regression design, seven diets with graded levels of α-tocopherol (aTOH) ranging from 38 to 710 mg/kg were tested in duplicate or triplicate tanks stocked with 110 Atlantic salmon (initial weight: 81 ± 2 g), respectively. After 11 weeks, 12 fish were sampled as freshwater smolts (FW-smolts), while the remaining fish were transferred to seawater and subjected to a challenge involving combined hypoxia and temperature stress before being sampled (seawater smolt [SW-smolt]). Additionally, 22 fish from each tank were transferred to a single sea cage and fed a common commercial diet for 5 months to assess the long-term impact of vitamin E nutrition during smoltification on key welfare indicators in post-smolt. No significant effects of dietary aTOH levels on growth performance were observed, but feed intake increased in FW-smolt fed up to 82 mg/kg. A high deposition of aTOH in liver tissue was observed in both FW- and SW-smolt fed more than 400 mg aTOH/kg. Malondialdehyde (MDA) levels in the liver decreased with aTOH supplementation with breakpoints at 457 mg/kg for FW-smolt and 99 mg/kg for SW-smolt, suggesting life-stage-specific differences in oxidative stress reduction. In SW-smolt, muscle astaxanthin levels increased linearly in response to dietary aTOH. Hematocrit and hemoglobin levels were unaffected in FW-smolt but displayed breakpoints in SW-smolt at 367 and 450 mg/kg, respectively. Welfare assessments revealed that fish fed 38 mg/kg during smoltification had a higher incidence of cataracts at the SW-smolt stage and complete vertebral fusion at the post-smolt stage. These findings suggest a minimum dietary aTOH requirement of 82 mg/kg to mitigate welfare issues, while tissue homeostasis, blood marks, and MDA suggest a practical requirement around 367-450 mg/kg.
SN - 1353-5773
SN - 1365-2095
ER -