|
Dietary effects of Haematococcus pluvialis in improving ovarian fluid biochemical and ionic parameters in rainbow trout broodstock
|
Najmeh Sheikhzadeh1 *   , Shalaleh Mousavi1 |
| 1-Department of Food Hygiene and Aquatic Animals, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran , nsheikh@tabrizu.ac.ir |
|
|
Abstract: (72 Views) |
Introduction: Freshwater microalga Haematococcus pluvialis accumulates numerous amount of astaxanthin, about 1,000- to 3,000-fold higher than salmon fillets and has achieved acceptance in fish farming and other markets as a concentrated form of natural astaxanthin. The beneficial effects of this microalga on fish pigmentation, growth, immunity, antioxidant system and reproductive performance have been intensely studied in recent decades. Ovulated eggs lay in the fish coelomic cavity. Ovarian fluid is accumulated before or at the beginning of ovulation. The ovarian fluid origin is largely unknown but it seems to be produced by the secretion of epithelial cells in the ovarian cavity, relating to metabolic activity of follicular cells. The amount of ovarian fluid in Salmonidae is fairly 10-30% of the total egg volume. Fish ovarian fluid is rich in proteins, ions, sugars and hormones. The ovarian fluid has several function, namely stabilizing the microenvironment around the micropyle, modulation of sperm performance as well as sperm and egg protection from adverse environmental conditions. Previous studies demonstrated that different indicators, including female endocrine glans situation, water physicochemical parameters, stresses as well as consumed feed quality and quantity could affect fish ovarian fluid properties. Despite their importance in female reproduction, the effect of female nutrition on ovarian fluid quality has been relatively little investigated. Therefore, the aim of this study was to evaluate the effects of feeding microalga Haematococcus pluvialis on the biochemical and ionic indices of ovarian fluid in rainbow trout broodstock.
Materials and Methods: A total of 60 rainbow trout broodstock (2845.9 ± 48.3 g) were randomly divided into four groups (three treatment groups and one control group) with three replicates. The treatment groups received diets containing 1, 2 and 3 grams kg-1 microalga Haematococcus pluvialis (Wuhan Yuancheng Technology Development Company,China) for 30 days, whereas the control group were fed with a basal diet without microalga. On day 30 of feeding trail, after anaesthetization into clove oil bath (50 μl L-1), stripping was carried out. After separating the ovarian fluid from collected eggs, fluids were centrifuged (4000g, 10min) and final supernatants were frozen at -80ºC until use. Biochemical parameters, namely acid phosphatase activity, lipid peroxidation product, glucose, protein, triglyceride and cholesterol levels as well as ionic parameters, including calcium, magnesium, sodium, and potassium- were measured in each supernatant. Total protein was measured by Lowry et al. (1951). Acid phosphatase activity, glucose, cholesterol and triacylglycerol levels were determined by enzymatic colorimetric methods. Lipid peroxidation product level was determined using the thiobarbituric acid test measuring the malondialdehyde (MDA) level in the samples. Cationic ions, namely calcium, magnesium, sodium, and potassium-were determined in ovarian fluid samples by flame photometer (Jenway PFP7, England).
Results and Discussion: The results showed that supplementing Haematococcus pluvialis could meaningfully improve lipid peroxidation product level in the ovarian fluid of all treated groups compared to the control group (p<0.05). Similarly, following the administration of some additives, low peroxidation product level and improved antioxidant indices in reproductive system were reported in fish species (Sheikhzadeh et al., 2012; Panjvini et al., 2022; Mohammed et al., 2024). Therefore, a convenient antioxidant can alleviate stresses in fish broodstock and protect sperms and eggs from lipid peroxidation (Sheikhzadeh et al., 2012). The antioxidant system present in adult fish body are not synthesized until late in the embryonic development of larval fish. This point represents the importance of improving larval quality through broodstock antioxidant enhancement. Feeding Haematococcus pluvialis could decrease the acid phosphatase activity in fish fed with the algae at 3 g kg-1 compared to the control fish (p<0.05). In the previous studies, an increase in the level of aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase levels in the fish seminal fluid during stresses were reported (Sheikhzadeh et al., 2010). Acid phosphatase and alkaline phosphatase enzymes are involved in phospholipids catabolism and yolk protein degradation. They leak from the intercellular part to the extracellular compartments during cell damages so these enzymes are regarded as indicators of egg degenerative processes in rainbow trout (Jia et al., 2015). During stresses, high lipid peroxidation product level and enormously generated free radicals help the cytotoxicity effect to propagate intracellularly, increasing the interaction of these radicals with phospholipids structure and inducing a peroxidation process that result in destroying the organ structure (Roa et al., 2015). In contrast, carotenoids can prevent lipid peroxidation and restore antioxidant enzymes, finally alleviating the tissue damages and declining acid phosphatase activity. Total protein level in the ovarian fluid of the treated brood stock were fairly similar to the control group, which were in the normal range. In the current study, glucose level in the ovarian fluid of fish treated with 2 and 3 g kg-1 microalga were significantly lower than the control fish. Similarly, lower serum glucose level in the fish fed astaxanthin and Haematococcus pluvialis were noted. Astaxanthin can protect pancreatic β-cells against glucose toxicity by inhibiting the huge destruction of these cells in the diabetic mice (Hussein et al., 2007). On the other side, during the fish culture, inevitable stresses can result in high serum glucose level following the glycolysis and gluconeogenesis mechanisms. Therefore, lower glucose level in the broodstock serum and then ovarian fluid by dietary administration of Haematococcus pluvialis is evident. The cholesterol content in broodstock ovarian fluid did not change in all treated groups, whereas triglyceride level was decreased in all treatment groups in comparison with the control group. Hussein et al. (2007) indicated a decline in plasma triglyceride level and adiponectin level improvement in rats fed astaxanthin oil. Adiponectin hormone can modulate some metabolic pathways, namely fatty acid metabolism and glucose regulation. Since presence of adiponectin has been proved in fish, it can be assumed that feeding Haematococcus pluvialis can improve the adiponectin level in rainbow trout and decrease glucose and triglyceride levels in broostock body. In the present study, cationic ionic levels, including calcium, magnesium, sodium, and potassium, were not affected in all groups (p>0.05) and observed within normal ranges. In the limited studies carried out on fish ovarian fluid, Melchor et al (2025) showed that green algae can enhance ionic balance and ovarian cells function. Similarly, Mohammed et al (2024) demonstrated that microalgae, as the main sources of minerals like iron, calcium, magnesium, can provide ionic optimum levels in fish plasma and ovarian fluid. So more studies are warranted to search the optimum doses of Haematococcus pluvialis on fish ionic indices.
Conclusion: These results indicate that dietary administration of microalga Haematococcus pluvialis at 3 gram kg-1 to rainbow trout broodstock can modulate some biochemical parameters, including acid phosphatase activity and lipid peroxidation product, glucose and triglyceride contents in rainbow trout broodstock ovarian fluid. Further studies are needed to investing the dual effects of Haematococcus pluvialis on fish broodstock ovarian fluid as well as larval qualities.
|
|
| Keywords: Haematococcus pluvialis, Ovarian fluid, Ionic parameters, Biochemical parameters, Rainbow trout |
|
|
Full-Text [PDF 609 kb]
(32 Downloads)
|
Type of Study: Research |
Subject:
Special
Received: 2026/01/20 | Accepted: 2026/01/30 | Published: 2026/03/30
|
|
|
|
|
|
|
| Send email to the article author |
|
|
|
| Add your comments about this article |
|
|
|
|
|
