Effects of blood source on growth, health, and water quality in the aquaculture of medicinal leech, hirudo verbanacarena, 1820

Abstract

Medicinal leech aquaculture is gaining importance due to increased clinical demand and conservation concerns resulting from overharvesting. Hirudo verbana, a CITES-listed and commercially valuable species, requires nutritionally adequate, species-specific feeding strategies for sustainable production. Although leeches feed on various vertebrate hosts in nature, the effects of different blood sources and forms on their growth, health, and water quality remain poorly understood in leech aquaculture. This study evaluated the impacts of natural and heparinized blood from cattle, sheep, goat, and live frog on leech growth, digestive response, and water quality. A total of 315 leeches were fed monthly for 3 months using selected blood sources. Parameters including specific growth rate (SGR), regurgitation, mortality, deformities, and water quality were monitored. The highest SGRs were observed in heparinized cattle (3.83%) and natural goat blood (3.61%), while sheep blood resulted in the lowest (1.87%). Regurgitation was associated with high ash and moisture content and low basophil levels. A strong negative correlation (r = - 0.853, P < 0.05) between basophils and regurgitation may indicate a potential biomarker for feed tolerance in medicinal leeches. Bloods with higher total protein and lower cholesterol and ash supported better growth. Groups fed with goat and sheep blood exhibited markedly higher conductivity and nitrogenous waste levels, especially ammonium. These findings emphasize the importance of blood composition in feed formulation for medicinal leeches and support the use of natural goat and heparinized cattle blood to enhance growth performance, health, and environmental outcomes in H. verbana aquaculture.