Growth indices, non-specific immune parameters, skin mucus protein profile and resistance to Saprolegnia parasitica in rainbow trout fed Mentha longifolia

Articles in Press

Document Type : Research Article

Authors

• Mohadeseh Heydari ¹
• Farid Firouzbakhsh ²

¹ Research center of Agricultural and natural resources, Education and Extension Organization (AREEO), Semnan, Iran

² Department of Fisheries, Faculty of Animal Science and Fisheries, Sari Agricultural Sciences and Natural Resources University

10.22067/ijvst.2025.90186.1429

Abstract

The development and implementation of nutritionally balanced diets are regarded as essential biological factors in improving growth and sustaining the health of fish. In the current study, the effects of Mentha longifolia hydroalcoholic extract were investigated on growth performance, Hemato-immunological responses and skin mucus protein in Oncorhynchus mykiss. A total of 360 fish (with an average weight of 10.17 ± 0.18 g) were acclimated to the experimental environment and distributed across 12 tanks (four groups in triplicate), maintaining a density of 30 fish per tank. Various concentrations of M. longifolia hydroalcoholic extract (0, 1, 2, and 3 g/kg) were incorporated into a basal diet. Following a 60-day feeding trial, the fish were challenged with Saprolegnia parasitica. All fish administered M. longifolia exhibited significant improvements in specific growth rate and weight gain, alongside a notable reduction in feed conversion ratio after compared to the control treatment. Moreover, the counts of red and white blood cells, serum respiratory burst activity, albumin levels, and total protein were significantly higher in the M. longifolia group in evaluation to the control group. Fish in the treatments receiving M. longifolia extract demonstrated a significant increase in survival rate following exposure to S. parasitica compared to the control group. Based on these findings, the incorporation of M. longifolia hydroalcoholic extract at a dosage of 1 g/kg in the diet of rainbow trout is recommended to enhance immune response, promote growth performance, and improve resistance to S. parasitica.

Keywords

• Mint
• Growth
• Immunity
• Blood
• Oomycete
• Oncorynchus mykiss

Main Subjects

• Aquatic animal diseases

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