Oregano Oil Supplementation Boosts Growth in Fish on Soy-Rich Diet

Jim Crocker
24th July, 2024

Oregano Oil Supplementation Boosts Growth in Fish on Soy-Rich Diet

Image Source: Natural Science News, 2024

Key Findings

  • Researchers from the University of New Hampshire studied the effects of oregano essential oil (OEO) on zebrafish fed with high soybean meal (SBM) diets
  • Zebrafish fed with 2% or 3% OEO showed growth performance similar to those on a fish meal (FM) diet, better than those on a high SBM diet
  • OEO at or above 2% may help reduce the negative impacts of high SBM diets, such as poor growth and intestinal inflammation
Soybean meal (SBM) has increasingly replaced fish meal (FM) in aquafeed due to its low cost and high availability. However, high inclusions of SBM in fish diets have been linked to reduced feed intake and intestinal inflammation. A recent study conducted by researchers from the University of New Hampshire aimed to explore the potential therapeutic effects of oregano essential oil (OEO) on mitigating these negative impacts using zebrafish as a model[1]. The study utilized five different diets to assess the efficacy of OEO in improving the growth performance and health of zebrafish. These diets included a reference FM-based diet, a control diet with 55.7% SBM inclusion, and three experimental SBM-based diets supplemented with 1%, 2%, or 3% OEO (labeled as OEO1, OEO2, and OEO3, respectively). The FM group demonstrated superior growth performance compared to the other groups. However, the OEO3 group showed no significant difference in mean weight and feed conversion ratio (FCR) compared to the FM group (p > 0.05) and exhibited significant improvements over the SBM group (p < 0.05). Similarly, the OEO2 group showed a total length comparable to the FM group (p > 0.05) and significantly higher than the SBM group (p < 0.05). The expression of inflammation-related genes did not differ significantly between the OEO groups and the SBM-only group. Despite this, the improved growth performance in the OEO2 and OEO3 groups suggests that OEO inclusion at or above 2% may help alleviate the adverse effects induced by a high SBM diet. These findings build upon earlier research that highlighted the negative impacts of SBM on fish health. For instance, previous studies have shown that soybean meal ingestion triggers intestinal inflammation in various fish species, including salmonids and carp[2]. Another study demonstrated that different concentrations of SBM in the diet could affect the severity and kinetics of enteritis in Atlantic salmon[3]. Furthermore, early nutrition with SBM has been shown to program zebrafish for later life responses, influencing inflammation and nutrient absorption[4]. The current study ties these earlier findings together by demonstrating a potential mitigation strategy for the adverse effects of high SBM diets. The inclusion of OEO at specific concentrations appears to improve growth performance and reduce the symptoms of intestinal inflammation, providing a practical approach to enhancing the health and productivity of aquaculture species. The methods used in this study were straightforward yet comprehensive. Zebrafish were chosen as the model organism due to their genetic similarities to other commercially important fish species and the availability of transgenic lines that facilitate in vivo analysis[2]. The researchers measured growth performance indicators such as mean weight, total length, and FCR, alongside assessing the expression of inflammation-related genes to gauge the overall health and immune response of the fish. In conclusion, the study conducted by the University of New Hampshire offers promising evidence that oregano essential oil can mitigate the negative impacts of high SBM inclusion in fish diets. By improving growth performance and potentially reducing intestinal inflammation, OEO presents a viable solution for enhancing the sustainability and health of aquaculture practices. This research not only corroborates previous findings on the adverse effects of SBM but also provides a practical mitigation strategy that could benefit the aquaculture industry significantly.

HerbsNutritionAnimal Science

References

Main Study

1) Effects of Oregano (Origanum vulgare) Essential Oil Supplementation on Growth Performance of Zebrafish (Danio rerio) Fed a High-Inclusion Soybean Meal Diet.

Published 23rd July, 2024

https://doi.org/10.1089/zeb.2024.0139

Related Studies

2) Soybean meal induces intestinal inflammation in zebrafish larvae.

https://doi.org/10.1371/journal.pone.0069983

3) Time-related changes of the intestinal morphology of Atlantic salmon, Salmo salar L., at two different soybean meal inclusion levels.

https://doi.org/10.1111/j.1365-2761.2009.01049.x

4) Soybean Meal and Soy Protein Concentrate in Early Diet Elicit Different Nutritional Programming Effects on Juvenile Zebrafish.

https://doi.org/10.1089/zeb.2015.1131


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