Effects of selenium supplementation on the antioxidation response in the rotifer ( Brachionus plicatilis )

Abstract

In the present study, the effects of selenium (Se) enrichment on the rotifer, Brachionus plicatilis, were investigated. Based on the results of six Se treatments obtained from triplicate experiments, we found that the efficiency of bioaccumulation by Se from non‐acid‐soluble sources was 62‐fold greater than that from acid‐soluble sources (Se‐Chlorella 15.6 ± 1.81% vs. selenite 0.25 ± 0.03%). However, supplementation of both acid‐soluble Se at low concentrations (≤40 µg per thousand rotifers) and Se‐Chlorella enhanced rotifer lifespan, increased the rate of spawning, inhibited lipid peroxidation, decreased levels of intracellular oxidization products and maintained the stability of mitochondrial membranes. These positive effects were correlated with the activities of antioxidant enzymes (e.g. catalase‐ and guaiacol‐dependent peroxidase) which increased along with the low Se concentrations (<80 µg per thousand rotifers). In contrast, the opposite effects were found when the rotifers were exposed to high Se concentrations (≥80 µg per thousand rotifers). The antioxidation and toxicity effects appeared to be correlated with the levels of total Se bioaccumulation. Above all, selenite, which is more toxic than Se‐chlorella, is less readily accumulated and biologically active. Se‐enriched rotifers fed by Se‐Chlorella are a fish larvae food supplement in aquaculture.

Long‐term incorporation of Selenium and Zinc in microalgae Isochrysis galbana and Nannochloropsis oculata and its effects on rotifer

“…Rotifers select food in the range of 4-10 µm, and using I. galbana and N. oculata enriched with minerals is more appropriate than Se-enriched C. vulgaris with a size of more than 15 µm (Sun et al, 2020). In this study, Sun et al (2020) showed that rotifer fed on Chlorella pyrenoidesa with 4 µm size gave better results than using C. vulgaris. Thus, one of the reasons for the low growth of the rotifer fed the 5 and 10 mg L −1 treatments, especially the latter, might be that the microalgae size was lower than the optimal to feed rotifers.…”

“…On the other hand, 2 mg L −1 was the best group in terms of growth (population density, egg number, egg ratio, SGR, N max and DT), contained the second‐highest level of Zn (69.26 ± 0.60 µg g −1 DW) and the amount of Se was 103.45 ± 4.99 µg g −1 DW. According to published results (Penglase et al, 2011; Sun et al, 2020), the amount of Se that is non‐toxic in rotifers is 22–113 µg g −1 DW, with the amount obtained using the 2 mg L −1 enrichment treatment being in this range. The highest specific growth rate (0.61 ± 0.03 day −1 ) was observed in the group fed with 2 mg L −1 of minerals, which is equal to the population growth rate of the rotifer fed with 3.3 μg g −1 DW Se‐enriched C .…”

“…This might be due to their inability to lay eggs, confirmed by the lower egg number and egg ratio than the other groups on the same days of culture (Figure 6). Sun et al, 2020), the amount of Se that is non-toxic in rotifers is 22-113 µg g −1 DW, with the amount obtained using the 2 mg L −1 enrichment treatment being in this range. The highest specific growth rate (0.61 ± 0.03 day −1 ) was observed in the group fed with 2 mg L −1 of minerals, which is equal to the population growth rate of the rotifer fed with 3.3 μg g −1 DW Se-enriched C.…”

“…oculata enriched with minerals is more appropriate than Se‐enriched C . vulgaris with a size of more than 15 µm (Sun et al, 2020). In this study, Sun et al (2020) showed that rotifer fed on Chlorella pyrenoidesa with 4 µm size gave better results than using C .…”

“…Efficient reproduction, and consequently population density, are important factors to be controlled in rotifer culture and both are affected by the concentration and variety of metals to which they are exposed (Hamre, Mollan, et al, 2008;Xu et al, 2015). Rotifers select food in the range of 4-10 µm, and using I. galbana and N. oculata enriched with minerals is more appropriate than Se-enriched C. vulgaris with a size of more than 15 µm (Sun et al, 2020). In this study, Sun et al (2020) showed that rotifer fed on Chlorella pyrenoidesa with 4 µm size gave better results than using C. vulgaris.…”