نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه شیلات، دانشکده علوم و فنون دریایی، دانشگاه هرمزگان، بندرعباس، هرمزگان
2 گروه شیلات، دانشکده علوم کشاورزی و منابع طبیعی، دانشگاه گرگان، گرگان، گلستان
3 گروه علوم و فناوری، دانشگاه سانیو، ایتالیا
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction: Bioactive compounds in plants are essential for aquatic animal nutrition because of their antioxidant and anti-inflammatory effects. They combat oxidative stress by neutralizing free radicals, protecting cells from damage. This protection helps maintain normal physiological functions critical for fish health. Furthermore, these compounds enhance the immune system, increasing fish resistance to pathogens and environmental stressors. Improved immunity reduces disease risk and mortality rates. Bioactive substances also support digestion and nutrient absorption, promoting better growth performance. Collectively, they boost fish resilience and biological functioning, making them valuable for sustainable aquaculture.
Materials and Methods: To examine the effects of ivy leaf extract, three dietary treatments with 100, 150, and 200 mg/kg extract (T100, T150 and T200, respectively) were prepared along with a control basal diet without extract (T0). Ingredients for the basal diet were precisely weighed and mixed, with the extract added accordingly. Pellets were made by mixing the ingredients, forming dough with water, grinding through a 2.4 mm pellet, air-drying, and storing at 4 °C. Two hundred and forty rainbow trout averaging 6.39 ± 0.35 g were acclimated for two weeks in 12 glass aquariums stocked with 20 fish each. After acclimation, tanks were randomly assigned to treatments with three replicates for an 8-week trial. Fish weights were measured biweekly to adjust feeding. Water quality was maintained with aeration, daily 70% water exchange, and stable temperature (13 ± 1°C), oxygen (8 ± 0.43 mg/L), and pH (7.5 ± 0.5). At the end, fish were anesthetized for biometric measurements, and growth indices including weight gain, specific growth rate, daily weight gain, and feed conversion ratio were calculated. Mucus was collected from six fish per treatment by gentle rubbing in saline solution, centrifuged, and stored at -70 °C. Immune assays measured lysozyme activity through bacterial lysis, total immunoglobulin by precipitation and protein quantification, and complement activity by rabbit red blood cell lysis. Data were statistically analyzed using tests for normality, variance, One-Way ANOVA, and Duncan’s multiple comparison with significance at P < 0.05.
Results and Discussion: The study found that adding ivy leaf extract significantly improved growth performance in rainbow trout, with the highest final weight and weight gain in T200. Immune responses in the mucus showed increased complement activity at T150 and higher total immunoglobulin and protein levels proportional to extract dose, peaking at T200. Lysozyme activity was significantly elevated only in the highest dose group. Feed conversion ratio improved significantly at T200, while lower doses had mixed effects. These findings demonstrate the dose-dependent benefits of ivy leaf extract on growth and mucosal immunity in rainbow trout. Herbal feed additives are an eco-friendly way to boost immunity and health in aquatic animals. Plants contain bioactive compounds like organic acids, flavonoids, and polyphenols that improve fish immune responses and overall wellbeing. In this study, ivy leaf extract enhanced growth and mucosal immunity in rainbow trout, likely by reducing oxidative stress and promoting energy use for growth. Ivy leaf extract increased lysozyme activity—a natural antibacterial enzyme—and raised total protein and immunoglobulin levels in skin mucus, strengthening the first line of defense. Polyphenols in plants support mucus production and quality, important for protecting against pathogens.
Conclusion: Plant extracts offer a sustainable alternative to antibiotics in aquaculture by improving innate and mucosal immunity. The study recommends 200 mg/kg ivy leaf extract supplementation for enhancing immune health in rainbow trout fingerlings.
کلیدواژه‌ها [English]
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