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Different dietary levels of astaxanthin on growth indices, sex hormones and sexual maturity indices in pre-broodstock beluga (Huso huso)
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Mir Hamed SDayed Hassani1   , Ayoub Yousefi Jourdehi2 , Ali Hallajian2 , Mahmoud Mohseni2 , Tooraj Sohrabi2 , Hooshang Yeganeh3 , Sajjad Ghasemian3 , Fatemeh Fadakar Masouleh3 |
1- International Sturgeon Research Institute, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization, Rasht, Iran & Caspian Sea International Research Institute, Agricultural Research, Education and Extension Organization (AREEO). Rasht. P.O. Box: 3464-41635
2- International Sturgeon Research Institute, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization, Rasht, Iran & انستیتو تحقیقات بین المللی تاسماهیان دریای خزر، سازمان تحقیقات، آموزش و ترویج کشاورزی (AREEO). رشت. صندوق پستی: 3464-41635
3- International Sturgeon Research Institute, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization, Rasht, Iran |
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Abstract: (21 Views) |
Introduction
Prolonged sexual maturation is a significant challenge in Huso huso aquaculture for both caviar and fry production. The most extended period of sexual maturation occurs during the II-III and III-IV stages (7–8 years), which are associated with substantial stagnation in capital investment. The decrease of the sexual maturation period and quality of gametes is greatly influenced by vitellogenesis quality that vitellogenesis is depended on time secretion of hormone 17 beta-estradiol. Under normal conditions, after temperature and photoperiod changes, hypothalamus secretes hypothalamic releasing hormone (GnRH), which releases gonadotropin hormones GTH1 and GTH2. GTH1 in the ovary triggers follicle cell receptors to produce 17-beta-estradiol, (the main sex steroid). 17-beta-estradiol diffuses across the membrane of liver cells, attaches to estrogen receptors, activates vitellogenin transcription and translation, and allows that fish to enter stage IV sexual development. Astaxanthin, a small molecule containing hydroxyl and unsaturated ketone groups, is a 17β-estradiol secretion stimulator, steroidogenesis accelerator, estrogen and progesterone secretion enhancer that lead to a sexual maturity period reduction in fish. Few studies have been undertaken to determine the effect of astaxanthin on gonadal growth and sexual maturation indicators in sturgeon. This study conducted on growth indices, hormone secretion, and sexual maturity in sturgeon prebroodstocks at sexual maturation stage II fed by dietary astaxanthin.
Methodology
Astaxanthin was derived from Carophyll® pink 10% (DSM-Bright Science, BrighterLiving™, Netherlands; CAS No.: 7542-45-2) provided by Abzico Company, Yasuj, Kohlakoyeh and Boyer-Ahmad Province, Iran. The experimental diets were formulated based on the nutrition requirements of Siberian sturgeon broodstock and available references (protein was 50%, lipid 1 15%, and energy was 18 mj/ kg dry matter in Excel Solver program. AST 50, AST 100, AST 150, and AST 200 diets were created by supplementing 50, 100, 150, and 200 mg/kg astaxanthin, respectively. Twenty-seven pre-broodstock fish with average weight and length of 16.16±0.16 and 140.65±13.2 cm at sexual maturity II were selected. The fish were fed 0.5% of their body weight for 645 days. the fish Gonadal development was examined with a monitor model (LG, 19M38HB, Korae) by making a longitudinal incision in the abdomen. sexual maturation hormones levels (testosterone, 17 beta estradiol and 17 alpha hydroxyprogesterone) were determined by blood sampling collected from caudal vein. Dry matter was measured by drying the sample at 105°C until constant weight was reached; crude protein was measured using the Kjeldahl method in three stages of digestion, distillation, titration, and multiplying the nitrogen obtained from each gram of dry matter by 6.25; ash was measured by burning the sample in an electric furnace (Muffle Furances, RHF 16/3/3216 P1 Model, England, Plymouth) at 550°C.Crude fat were measured by Soxhlet lipid extraction using ether solvent reaching a boiling point of 50-60°C for 4-6 hours in a Soxhlet extractor (Gerhart Soxthoterm SOX Hamburg, Hamburg, German), and total energy were measured using a bomb calorimeter (Calorimeteradiabatic C-400 IKA, Heiterbeini, GMBIL, Brussels, Belgium) (AOAC, 1995).17 alpha hydroxyprogesterone was determined in ng/gr using the Monobind ELISA kit, 17 beta estradiol and testosterone levels were determined using kits (Immunotech, France) and the II25 detector via radioimmunoassay (RIA) using a GammaCounter (LKB, France) in ng/ml using the modified method of Cattaldi et al. (1998).
Results
Fish fed the C200 diet exhibited the highest final weight, body weight gain percentage, and specific growth rate, along with the lowest feed conversion ratio (p<0.05). There were no significant variations in estradiol, testosterone, and alpha-hydroxyprogesterone levels in fish during the first biometric period following the introduction of pre-broodstock to the pond (sexual maturation II) (p>0.05). In second biometry, there was no significant difference in estradiol and testosterone hormones secretion after 10 months of feeding. Fish fed the AST0 had an estradiol level of around 0.3±0.05 ng/ml. However, fish fed the AST 50, AST 100, and AST 150 had levels of 0.27±0.01, 0.25±0.03, and 0.25±0.01 ng/ml, respectively (p>0.05). Fish fed AST 200 had higher levels (0.35±0.04 ng/ml). The testosterone level in fish fed AST 0 was 0.27±0.04 ng/ml. Testosterone levels decreased in fish fed AST 50, AST 100, and AST 150 (0.17±0.00, 0.18±0.006, 0.18±0.01 ng/ml), whereas increased in fish fed AST 200 compared to AST 0 (p>0.05). There was no significant difference in the amount of 17 alpha-hydroxyprogesterone between treatments, however the highest amount was seen in the blood serum of fish fed a AST 200. In third biometry, Broodstock fed by AST 200 had the highest testosterone levels (0.71±0.19 ng/mg), significantly higher than other treatments (p<0.05). Fish fed with AST150 and AST200 showed the highest amounts of testosterone (0.78 ± 0.4 and 0.71 ± 0.19 ng/mg, respectively) (p<0.05). also, Broodstock fed AST100 and AST200 showed highest 17-alpha-ydroxyprogesterone (42±0.08 and 43±0.08 ng/ml, respectively) compared to fish fed AST0 dietary (p<0.05). But, Estradiol hormone secretion in fish fed with AST 50, AST 100, and AST 200 had a significant increase at last sampling stage and reached to 0.76±0.092 ng/ml (p<0.05). The testosterone level in fish fed a C0 was 1.63±0.24 ng/ml. No significant difference in testosterone secretion was seen in broodstock fed with C0 compared to AST 50, C100, and AST 150. However, broodstock serum testosterone fed with C200 increased and reached 7.5±1.1 ng/mL. Fish fed with AST 50, AST 100, and AST 150 had significantly lower levels of alpha-ydroxyprogesterone compare to AST 0. Fish fed with C200 also had lower levels of alpha-hydroxyprogesterone in their serum compared to fish fed AST 0 diet (p<0.05). On the other hand, The results obtained from fish laparoscopic observations showed that the broodstock fed a diet containing C200 were entering stage IV and immature oocytes and eggs were visible in the ovarian tissue, while the broodstock fed a diet lacking astaxanthin as well as the broodstock of AST 50, AST 100 and AST 150 treatments were stopped at stage III sexual maturation.
Conclusion and discussion
In agreement with our result, Xie et al. (2020) showed that astaxanthin supplementation at levels of 75 and 100 mg/kg improved growth parameters in largemouth bass (Micropterus salmoides). Similarly, astaxanthin supplementation in the diets of white leg shrimp (Litopenaeus vannamei), pacu (Piaractus mesopotamicus) (Bacchetta et al., 2019), and tiger shrimp (Penaeus monodon) (Niu et al., 2015) increased growth and decreased feed conversion ratio. According to Zhang et al. (2013b), carotenoid pigments improve nutritional digestion, absorption, and feed utilization by enhancing digestive enzyme activity and increasing feed intake. Carotenoids have sexual maturation-stimulating properties that can induce vitellogenesisy the of sex steroids synthesis increasing (17β-estradiol) and quicker oocyte maturation accelerate in rainbow trout (Örn et al., 2003). Fish that were provided the C200 diet showed higher levels of estradiol and 17α-hydroxyprogesterone compared to those fed the AST0 diet after 16 months of feeding. Laparoscopic observations confirmed that the fish fed AST200 had passed the III stage of sexual maturation and vitellogenesis had occurred. Similar results were reported in the bull tongue shoe (Cynoglossus semilaevis) (Xu et al., 2017), the large freshwater shrimp (Macrobrachium rosenbergii) (Tao et al., 2025). In this study, broodstock fed with AST200 showed a rapid decrease in 17α-hydroxyprogesterone levels as they near approach of stage IV. During oocyte maturation, HSDH-20β converts 17α-hydroxyprogesterone in granulosa cells to 17α-20β-hydroxy progesterone, it seems be, 17α-hydroxyprogesterone decreasing in C200 treated broodstock may be due to oocyte maturation. At this stage, follicles are poised to produce steroids in order to stimulate ultimate maturation.
Conflict of interest
There is no conflict of interest between authors
Acknowledgment
This article is derived from the project "Investigation of the effect of dietary astaxanthin and HUFA fatty acids supplementation on gonads and reproductive indices in farmed female Huso huso" with code 990585-98001-007-12-32-12. The authors express their gratitude to all individuals who provided scientific and practical supports. |
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| Keywords: Key word: Huso huso, Astaxanthin, Sexual maturation |
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Full-Text [PDF 877 kb]
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Type of Study: Research |
Subject:
تغذيه
Received: 2025/10/1 | Accepted: 2026/07/1
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