Seaweed Diet Boosts Growth, Immunity, and Disease Resistance in Fish

Jim Crocker
14th May, 2024

Seaweed Diet Boosts Growth, Immunity, and Disease Resistance in Fish

Resistance against the pathogen Pseudomonas aeruginosa (1) was significantly improved by adding the green seaweed Caulerpa racemosa (2) to the diet of Cirrhinus mrigala (3), which resulted in enhanced growth performance and innate immune response.

Composite: Natural Science News / CC BY-SA. [Sources]
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Key Findings

  • The study by Bharathiar University found that feeding Cirrhinus mrigala fish with Caulerpa racemosa extract improved their growth and immune responses
  • Fish fed with 4.5% and 6.5% C. racemosa extract showed significant increases in weight gain and specific growth rates
  • The fish also exhibited enhanced immune responses and higher survival rates against the pathogen Pseudomonas aeruginosa
The green seaweed Caulerpa racemosa has been recognized for its beneficial properties in both animal forages and human use since ancient times. A recent study conducted by Bharathiar University aimed to explore the antioxidant and phytochemical properties of C. racemosa and their effects on growth parameters, biochemical components, non-specific immunological parameters, and disease resistance to Pseudomonas aeruginosa in Cirrhinus mrigala[1]. The study was structured with five experimental groups (T1–T5). Groups T2–T5 were administered C. racemosa extract at varying concentrations of 0.5%, 2.5%, 4.5%, and 6.5% supplemented with basal diets, while T1 served as the control group devoid of the extract. The trial lasted forty-five days. The primary focus of the study was to determine whether the inclusion of C. racemosa extract in the diets of C. mrigala could enhance growth performance and boost immune responses, thereby improving resistance to P. aeruginosa, a common pathogen in fish farming. This bacterium has been shown to cause significant mortality in fish, with strains exhibiting multi-drug resistance to common antibiotics such as amoxicillin, cefotaxime, tetracycline, and gentamicin[2]. The findings revealed that the groups fed with C. racemosa extract exhibited improved growth parameters compared to the control group. Specifically, the fish in groups T3 (4.5% extract) and T4 (6.5% extract) showed significant increases in weight gain and specific growth rates. These results suggest that C. racemosa can be an effective dietary supplement to enhance growth in C. mrigala. In terms of biochemical components, the study observed that the experimental groups had higher levels of essential nutrients and antioxidants. This aligns with previous research indicating that marine seaweed can be a rich source of nutrients beneficial for fish growth[3]. The increased antioxidant levels in the fish fed with C. racemosa extract could potentially mitigate oxidative stress, which is crucial for maintaining fish health during periods of stress. The study also evaluated non-specific immunological parameters, which are part of the fish's innate immune system. The fish fed with C. racemosa extract showed enhanced immune responses, including higher levels of lysozyme activity and phagocytic activity. These improvements in immune function are critical for disease resistance, especially against pathogens like P. aeruginosa. Previous studies have highlighted the importance of boosting the innate immune system in fish to improve survival rates during high-stress periods[4]. Moreover, the study demonstrated that fish in the experimental groups had higher survival rates when exposed to P. aeruginosa compared to the control group. This indicates that C. racemosa not only enhances growth and immune responses but also provides a protective effect against bacterial infections. The presence of virulence genes such as oprL and toxA in P. aeruginosa strains underscores the need for effective disease management strategies in aquaculture[2]. In conclusion, the study by Bharathiar University provides compelling evidence that C. racemosa extract can be a valuable dietary supplement for C. mrigala. It enhances growth performance, boosts immune responses, and increases resistance to P. aeruginosa. These findings suggest that incorporating marine seaweed into fish diets could be a practical approach to improving fish health and productivity in aquaculture.

BiochemAnimal ScienceMarine Biology

References

Main Study

1) Effect of dietary seaweed Caulerpa racemosa on growth, biochemical, non-specific immunity, and disease resistance to Pseudomonas aeruginosa in Cirrhinus mrigala

Published 13th May, 2024

https://doi.org/10.1186/s41936-024-00365-x

Related Studies

2) Emerging MDR-Pseudomonas aeruginosa in fish commonly harbor oprL and toxA virulence genes and blaTEM, blaCTX-M, and tetA antibiotic-resistance genes.

https://doi.org/10.1038/s41598-020-72264-4

3) Evaluation of red seaweed Gracilaria arcuata as dietary ingredient in African catfish, Clarias gariepinus.

https://doi.org/10.1016/j.sjbs.2015.11.006

4) The use of immunostimulants in fish larval aquaculture.

Journal: Fish & shellfish immunology, Issue: Vol 19, Issue 5, Nov 2005


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