Selenium-Boosted Algae Diet Enhances Fish Health and Immunity

Greg Howard
21st March, 2024

Selenium-Boosted Algae Diet Enhances Fish Health and Immunity

Image Source: Natural Science News, 2024

Key Findings

  • In a study at Mansoura University, selenium nanoparticles improved Nile tilapia fish health
  • Fish fed SeNPs had better blood markers, indicating improved metabolic health
  • SeNPs boosted the fish's immune genes and did not cause any cell damage
Selenium, a trace element essential for health, has been the focus of recent research at Mansoura University. Scientists have been exploring the benefits of selenium nanoparticles (SeNPs) in animal diets to boost immune responses and improve overall health. The latest study[1] takes this research underwater, investigating how SeNPs affect Nile tilapia, a widely farmed fish. Tilapia are a cornerstone of aquaculture, but they can be vulnerable to stress and disease, which compromises both their welfare and the sustainability of tilapia farming. In this context, the study aimed to determine if SeNPs could enhance the fish's immunity and protect their intestinal integrity—crucial factors for a healthy aquaculture environment. The study involved 180 Nile tilapia, each weighing between 54 to 57 grams. Over eight weeks, these fish were divided into groups and fed diets with varying concentrations of SeNPs: 0 mg/kg (control), 0.75 mg/kg, and 1.5 mg/kg. The nanoparticles used were not just any SeNPs; they were green synthesized using the microalga Pediastrum boryanum. This method of production is considered environmentally friendly, adding an extra layer of sustainability to the study. After the feeding trial, a range of indicators was measured. These included serum biochemical indices like alkaline phosphatase (ALP), lactate dehydrogenase (LDH), cholesterol, and high-density lipoproteins (HDL)—all markers of metabolic health and stress. Tissue samples were also examined to determine the selenium concentration within the muscle, and genes related to antioxidant activity and inflammation were analyzed for their expression levels. The results were promising. SeNPs supplementation led to a significant decrease in ALP, LDH, and cholesterol levels, while HDL—a good form of cholesterol—increased. This suggests an overall improvement in the metabolic health of the fish. Moreover, selenium levels in the muscle tissues rose with increasing doses of SeNPs, showing that the fish were effectively absorbing the nutrient. On a genetic level, the study found an upregulation of genes involved in the body's antioxidant defenses, such as glutathione reductase (GSR) and glutathione synthetase (GSS), in the groups given SeNPs. These genes play a vital role in combating oxidative stress, which can damage cells and lead to disease. In terms of immune response, the SeNPs-fed fish showed increased transcription of genes for pro-inflammatory cytokines like interleukin 8 (IL-8) and interleukin 1 beta (IL-1β), particularly at the higher dose of 1.5 mg/kg. These molecules are part of the body's first line of defense against infection. Importantly, there were no signs of apoptosis (programmed cell death) or cell damage, as indicated by the expression of proliferating cell nuclear antigen (PCNA) and caspase-3 genes and supported by histopathological evidence. This suggests that the SeNPs were not toxic to the fish at the administered doses. Additionally, SeNPs supplementation had a positive effect on mucin-producing goblet cells in the intestine, which are crucial for maintaining a healthy gut barrier. This aligns with earlier studies[2][3], which indicated that SeNPs could improve gut microarchitecture and barrier function in broilers, and even enhance the development of goblet cells in the jejunum, a part of the small intestine. This study's findings are in step with previous research demonstrating the potential of SeNPs as a dietary supplement to support animal health. For instance, earlier investigations have shown that SeNPs can ameliorate stress in broilers caused by high stocking density[2], and even promote intestinal health by fostering the development of goblet cells[3]. Moreover, the antioxidant properties of microalgae, such as those used to synthesize the SeNPs in this study, have been confirmed in other research[4], underscoring the potential of these organisms in producing beneficial supplements. In conclusion, the Mansoura University study provides compelling evidence that SeNPs, especially those synthesized from green microalgae, can be a valuable addition to fish diets. By enhancing immune responses and maintaining intestinal health, SeNPs could help make aquaculture more sustainable and productive. This research not only benefits the field of aquaculture but also contributes to our understanding of how trace elements like selenium can be used to improve animal health in a variety of contexts.

NutritionBiotechAnimal Science


Main Study

1) Dietary microalgal-fabricated selenium nanoparticles improve Nile tilapia biochemical indices, immune-related gene expression, and intestinal immunity.

Published 18th March, 2024

Related Studies

2) Effect of Selenium Nanoparticles and Mannan Oligosaccharide Supplementation on Growth Performance, Stress Indicators, and Intestinal Microarchitecture of Broilers Reared under High Stocking Density.

3) Selenium Nanoparticles Improved Intestinal Health Through Modulation of the NLRP3 Signaling Pathway.

4) Characterization of Novel Selected Microalgae for Antioxidant Activity and Polyphenols, Amino Acids, and Carbohydrates.

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