Iranian Scientific Fisheries Journal

fa مقاله علمی – پژوهشی:‌ تأثیر سطوح مختلف لیزین و هیستیدین در جیره فیل‌ماهی (Huso huso) بر شاخص‌های آنتی‌اکسیدانی کبد Effect of different lysine and histidine levels in the diet of beluga sturgeon (Huso huso) on liver antioxidant indices تغذيه تغذيه پژوهشي Research هدف از این پژوهش، بررسی اثرات سطوح مختلف لیزین و هیستیدین در جیره غذایی فیل‌ماهی(Huso huso) بر عملکرد شاخص‌های آنتی‌اکسیدانی و میزان استرس اکسیداتیو در بافت کبد بود. بدین منظور، تعداد 315 عدد فیل‌ماهی با میانگین وزنی اولیه 2 ± 20 گرم به صورت تصادفی و پس از دو هفته سازگاری، در  7 تیمار با سه تکرار در 21 مخزن فایبرگلاس 2000 لیتری با تراکم 15 عدد در هر مخزن توزیع شدند. سطوح لیزین شامل 4/0و 8/0 درصد و سطوح هیستیدین شامل2/0 ، 5/0و 8/0 درصد در جیره پایه بود. پس از 8 هفته تغذیه، نمونه‌برداری از بافت کبد جهت اندازه‌گیری شاخص&rlm;های آنتی اکسیدانی شامل فعالیت آنزیم‌های سوپراکسید دیسموتاز (SOD)،کاتالاز (CAT)،گلوتاتیون‌پراکسیداز (GPx) و شاخص&rlm;های پراکسیداسیون لیپیدی: مالون‌دی‌آلدئید (MDA) صورت گرفت. نتایج نشان داد که بالاترین سطوح ترکیبی (8/0 درصد لیزین و 8/0 درصد هیستیدین) باعث بهبود معنی‌دار فعالیت سوپراکسید دیسموتاز، کاتالاز، گلوتاتیون پراکسیداز و کاهش سطح مالون دی آلدئید درکبد فیل‌ماهی گردید (05/0p<). یافته‌های این مطالعه نشان‌دهنده نقش کلیدی لیزین و هیستیدین در سطوح بهینه در تعدیل استرس اکسیداتیو و ارتقاء سلامت کبد در فیل‌ماهی است. Introduction The beluga sturgeon (Huso huso) is one of the most economically important fish species in aquaculture, particularly for caviar production (Mohseni et al., 2016). Oxidative stress is a major challenge in aquaculture, leading to cellular damage, impaired growth, and increased susceptibility to diseases. It occurs when the balance between the production of reactive oxygen species (ROS) and the antioxidant defense system is disrupted. Fish, like other vertebrates, rely on endogenous antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) to neutralize oxidative stress (Naji et al., 2023). Nutritional strategies play a fundamental role in modulating oxidative stress (Feng et al., 2013: Huang et al., 2021; Huang et al., 2022). Among various nutrients, amino acids have gained increasing attention due to their involvement in antioxidant defense mechanisms. Lysine is a key essential amino acid required for protein synthesis, enzyme function, and immune response (Ahmed and Ahmed, 2021; Dou et al., 2023), while histidine serves as a precursor for carnosine, a potent antioxidant that protects tissues against oxidative stress (Ramos-Pinto et al., 2021; Hussein et al., 2023). Studies suggest that histidine supplementation can enhance antioxidant capacity by scavenging free radicals and reducing lipid peroxidation. Despite their importance, the optimal levels of lysine and histidine required to mitigate oxidative stress in beluga sturgeon remain unclear. This study aimed to investigate the effects of different dietary levels of lysine and histidine on antioxidant enzyme activity and oxidative stress markers in the liver of beluga sturgeon. The findings will contribute to developing optimized dietary formulations to improve fish health and performance in aquaculture. Methodology At International Sturgeon Research Institute, a total of 315 juvenile beluga sturgeons (Huso huso) with an initial mean weight of 20±2 g housed in recirculating aquaculture systems (RAS) equipped with biological filtration, aeration, and temperature control to ensure optimal conditions. The experimental diets were formulated based on a fishmeal-based basal diet with varying levels of lysine (0.4% and 0.8%) and histidine (0.2%, 0.5%, and 0.8%) including control and six Treatments (Control: 0% Lysine and Histidine, T1: 0.4% Lysin -0% Histidine; T2: 0.8% Lysin -0% Histidine; T3:0% Lysin -0.2% Histidine; T4:0% Lysin -0.5% Histidine;T5: 0.4% Lysin -0.2% Histidine; T6:0.8% Lysin -0.8% Histidine), each consisting of three replicates (15 fish per replicate). The ingredients were finely ground, mixed, pelleted, and dried before storage. The fish were fed four times daily (08:00, 14:00, 20:00 and 2:00) at a rate of 3% of body weight for a period of eight weeks. Feed intake was monitored daily to ensure uniform consumption across treatments. At the end of the feeding trial, fish were euthanized with clove powder and liver samples were collected and stored at -80°C for biochemical analysis (Bahrami et al.,2022). In the present study liver antioxidant enzymes activity including Catalase, Superoxide dismutase, Glutathione peroxidase, Glutathione reductase, as well as the lipid peroxidation index, malondialdehyde were evaluated in Huso huso fed with different levels of lysine and histidine. Enzymes activity was determined using spectrophotometric assays, following standard protocols. Results Catalase activity in samples that received the combination of lysine and histidine showed a significant increase. The highest catalase activity was observed in the treatment with levels of 0.8% lysine and 0.8% histidine (P<0.05).  The difference between treatments 5 and 6 was not significant (P>0.05), while a significant difference was observed with other groups (P<0.05). Analysis of superoxide dismutase activity showed that adding high amounts of lysine and histidine (0.8 lysine and 0.8 histidine) increased the highest level of activity of this enzyme. Unlike catalase, the difference between treatments 5 and 6 was significant (P<0.05). GPx activity increased significantly with increasing histidine and lysine. Treatment 6 showed the highest level of activity (P<0.05). GR activity gradually increased with increasing histidine and lysine levels in the diet. The highest level of activity of this enzyme was also related to treatment 6. Discussion and conclusion The observed increase in antioxidant enzyme activity (SOD, CAT, and GPx) in response to higher lysine and histidine supplementation suggests that these amino acids play a crucial role in enhancing the antioxidant defense system of beluga sturgeon. Histidine, as a precursor of carnosine, likely contributed to the neutralization of reactive oxygen species, thereby protecting liver tissue from oxidative damage (Holeček, 2020; Sui et al., 2023). Additionally, the reduction in MDA levels supports the hypothesis that optimal dietary amino acid levels mitigate lipid peroxidation and oxidative stress. Similar findings have been reported in other fish species, indicating that adequate lysine and histidine supplementation improves oxidative stability and overall health. This study highlights the importance of lysine and histidine in regulating oxidative stress and enhancing hepatic antioxidant defense mechanisms in beluga sturgeon. The optimal dietary levels (0.8% lysine and 0.8% histidine) significantly improved antioxidant enzyme activity while reducing lipid peroxidation markers. These findings provide valuable insights into nutritional strategies for improving fish health in aquaculture. Future studies should investigate long-term effects of amino acid supplementation on growth performance, immune response, and metabolic functions in sturgeon. Conflict of Interest The authors declare no conflict of interest Acknowledgment The authors wish to extend their heartfelt gratitude to the International Sturgeon Research Institute at the Agricultural Research Education and Extension Organization (AREEO). We also sincerely appreciate the support from the Beluga Sturgeon Farm for providing fish and diets essential for our research. It is <div style="text-align: justify;">important to note that this study did not receive any specific funding from public or non-profit sector</div> agencies. فیل‌ماهی (Huso huso) , لیزین, هیستیدین, شاخص‌های آنتی‌اکسیدانی کبد Beluga sturgeon (Huso huso), lysine, histidine, liver antioxidant indices 47 58 http://isfj.ir/browse.php?a_code=A-10-579-20&slc_lang=fa&sid=1 Mahmoud Mohseni محمود محسنی mahmoudmohseni73@gmail.com 100319475328460040330 100319475328460040330 Yes International Sturgeon Research Institute, National Fisheries Science Research Institute, Agricultural Research, Education and Extension Organization, Rasht, Gilan انستیتو تحقیقات بین المللی ماهیان خاویاری، موسسه تحقیقات علوم شیلاتی کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، رشت، گیلان Sara Mehdizadeh سارا مهدی زاده smehdizadeh@semnan.ac.ir 100319475328460040331 100319475328460040331 No Food Hygiene and Aquatic Animal Department, Faculty of Veterinary Medicine, Semnan University, Semnan, Iran بخش بهداشت مواد غذایی و آبزیان ، دانشکده دامپزشکی، دانشگاه سمنان، سمنان، ایران mahmoud Mahdavi علی مهدوی mahmoudmohseni@yahoo.com 100319475328460040332 100319475328460040332 No Food Hygiene and Aquatic Animal Department, Faculty of Veterinary Medicine, Semnan University, Semnan, Iran بخش بهداشت مواد غذایی و آبزیان ، دانشکده دامپزشکی، دانشگاه سمنان، سمنان، ایران Somayeh Hassanpour سمیه حسن پور لسکوکلایه somayehhasanpoor1982@yahoo.com 100319475328460040333 100319475328460040333 No Beluga Sturgeon Farm, Rasht, Gilan, Sangar مزرعه پرورش ماهی خاویاری بلوگا، رشت، گیلان، سنگر