Long-term organic selenium supplementation overcomes the trade-off between immune and antioxidant systems in pacu ( Piaractus mesopotamicus )

Abstract

Selenium (Se) is an essential nutrient for antioxidant defenses in fish because of its role in preventing immunosuppression caused by oxidative stress. In this study it was demonstrated the relation between the oxidative stress and immune status after a long Se supplementation period, as a result of the evaluation of immunological, hematological and antioxidant responses, as well as growth performance of pacu fed diets supplemented with different concentrations of organic selenium (0, 0.3, 0.6, 0.9, and 1.8 mg Se-yeast/kg, but the final analyzed selenium concentrations were 0.72, 0.94, 1.15, 1.57 and 2.51 mg/kg, respectively) for 65 days. Dietary Se supplementation at 1.15 mg Se-yeast/kg (analyzed value) restored the production of antioxidant enzymes (glutathione peroxidase (GPx) and glutathione S-transferase (GST)), and consequently allowed the increased of some immunological parameters (leukocyte respiratory burst activity and lysozyme activity), hematological parameters (red blood cell count (RBC), hematocrit (HTC), mean corpuscular volume (MCV), and white blood cell count (WBC)). Se supplementation in pacu diets at 1.15 mg Se-yeast/kg for 65 days improved immune response and antioxidant defenses, suggesting that oxidative stress impairs immune system response to prevent excessive reactive oxygen species in cells and indicating the occurrence of a physiological trade-off between immune and antioxidant systems. Higher Se levels, such as 1.57 mg Se-yeast/kg increased the leukocyte respiratory burst activity, the WBC and thrombocyte counts, the RBC and HTC, and the GST and GPx enzymes. However, 2.51 mg Se-yeast/kg decreased the lysozyme levels, the WBC and thrombocyte counts, the RBC, HTC and MCV, and the GST and GPx enzymes. Those findings are important to future studies because showed the negative effect of oxidative stress on immunity, and may help to prevent any inhibition of the expected immune response after immunomodulators administration and vaccination. Also it was possible to meet the dietary selenium requirement of pacu, that was estimated to be 1.56 mg/kg.

Dietary nano‐selenium enhances antioxidant capacity and hypoxia tolerance of grass carp Ctenopharyngodon idella fed with high‐fat diet

“…This is in agreement with results from other studies. The growth parameters (final average weight, WG and SGR) of the loach Paramisgurnus dabryanus (Sauvage) were not significantly affected by diet Se‐chitosan (Victor et al, ), and the growth performance of pacu ( Piaractus mesopotamicus ) was not significantly affected by different levels of Se‐yeast in diet (Takahashi et al, ). And the decreased growth rate in fish fed diet with 0.3 mg/kg Nano‐Se can be explained by the significantly reduced intraperitoneal fat and lipid content in hepatopancreas (not shown data), and this effect of Se on lipid accumulation has been reported by previous study (Liu et al, ).…”

Interactive effects of dietary Nano selenium and vitamin E on growth, haematology, innate immune responses, antioxidant status and muscle composition of rainbow trout under high rearing density

“…Fish antioxidant capacity depends, in part, on dietary supply of essential antioxidants, such as Se and vitamin E (Küçükbay et al, ; Liu et al, ; Trenzado et al, ). It is reported that antioxidant supplementation reduces oxidative stress and improves the immune functions of fish (Takahashi et al, ). Selenium and vitamin E act as biological antioxidants to protect cellular membranes from oxidative damage (Rotruck et al, ).…”

“…Selenium as a component of glutathione peroxidase (GPx) and thioredoxin, which decompose hydroperoxide radicals, directly protect the cellular membranes from oxidative damage (Bell, Cowey, Adron, & Shanks, ; Biller‐Takahashi et al, ; Rotruck et al, ). Adequate levels of selenoproteins such as GPx and thioredoxin are particularly important for maintaining proper immune response (Arthur, McKenzie, & Beckett, ; Takahashi et al, ). This nutrient also plays an important role in preventing the immunosuppressive action of oxidative stress (Biller‐Takahashi et al, ; Hoffmann, ), and this is important particularly under intensive fish culture, which stress could lead to immunosuppression and may experience significant losses from diseases (Takahashi et al, ).…”

“…Adequate levels of selenoproteins such as GPx and thioredoxin are particularly important for maintaining proper immune response (Arthur, McKenzie, & Beckett, ; Takahashi et al, ). This nutrient also plays an important role in preventing the immunosuppressive action of oxidative stress (Biller‐Takahashi et al, ; Hoffmann, ), and this is important particularly under intensive fish culture, which stress could lead to immunosuppression and may experience significant losses from diseases (Takahashi et al, ). Selenium nanoparticle (Nano Se) is the new Se form and has attracted remarkable attention, due to its higher bioavailability and low toxicity (Rezvanfar et al, ; Shi et al, ; Wang, Zhang, & Yu, ).…”

Improvement of flesh quality in rainbow trout (Oncorhynchus mykiss ) fed supranutritional dietary selenium yeast is associated with the inhibited muscle protein degradation

“…It is reported that Se-yeast roughly contained 700-900 mg/kg selenomethionine in its selenocompounds (Block et al, 2004;Ip et al, 2000). As an excellent organic Se product, Seyeast has been extensively studied as a Se supplement in the feeds of various animals, such as lambs (Juniper, Phipps, Ramos-Morales, & Bertin, 2009;Vignola et al, 2009), goats (Shi et al, 2011), pigs (Pinto et al, 2012;Zhao et al, 2016), chickens (Ahmad et al, 2012;Wang & Xu, 2008) and fish (Ozluer-Hunt et al, 2011;Liu et al, 2017;Takahashi et al, 2017).…”