The effect of replacing dietary fish oil with animal and vegetable oil on biochemical and immune parameters of rainbow trout (Oncorhynchus mykiss) serum

Document Type : Research Paper

Authors
1 Deps. of Fisheries, Faculty of Natural Resources, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran.
2 International Sturgeon Research Institute, Iranian Fisheries Science Research Institute, Rasht, Iran.
Abstract
The aim of this study was to investigate the effect of replacing beef tallow and canola oil with dietary fish oil on hematological parameters of rainbow trout (Oncorhynchus mykiss). For this purpose, 250 fish with an average weight of about 20 grams were selected and randomly with 3 replications as: treatment 1 or control (diet containing 100% fish oil), treatment 2 (diet containing 50% fish oil and 50% beef tallow, treatment 3 (diet containing 50% fish oil and 50% canola oil) and treatment 4 (diet containing 50% fish oil, 25% beef tallow and 25% canola oil) were treated in a 500 liter fiberglass basin. The fish were fed twice for 90 days. At the end, blood samples were taken from the caudal vein and blood indices were measured. The results showed that the highest mean final weight, weight gain and survival rate belonged to treatment 1 and 4 and the lowest amount of these parameters belonged to treatment 2 (P≥0.05). The amount of cholesterol in the control sample was the highest. The amount of cholesterol in treatment 3 was lower than other treatments. The lowest amount of triglyceride was observed in treatment 2. The highest levels of glucose and cortisol were observed in treatment 2. No significant difference in the amount of immunoglobulin and lysozyme was observed among different treatments. According to the results the replacement of 25% beef tallow oil and 25% canola oil instead of fish oil in Rainbow trout diet is possible.

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Volume 38, Issue 2
Summer 2025
Pages 148-163

  • Receive Date 11 June 2024
  • Revise Date 15 April 2025
  • Accept Date 14 July 2025