Growth response, proximate and bioactive compositions of Chlorella vulgaris cultured on different quantities of pure poultry manure

Microalgae are a diverse group of unicellular photosynthetic organisms which contain high levels of proteins, lipids, carbohydrates, pigments, minerals and vitamins in different quantities, thus, could be used as feed supplement in catfish production. The study investigated growth response, proximate composition and bioactive compounds present in Chlorella vulgaris cultured on different quantities of pure poultry manure. Pure 200cl sample of C. vulgaris isolates was procured from the Limnology Unit of National Institute for Freshwater Fisheries Research (NIFFR), Niger State. Five different weights (10kg, 20kg, 30kg, 40kg and 50kg) of pure and dried poultry droppings were each soaked in 10 liters of water for two hours and inoculated with 13.33cl C. vulgaris isolates following standard procedures. Each treatment was then poured into70 litres culture plastic tanks containing 40 liters of clean water and was used for the culture of C. vulgaris. The culture systems were exposed to 10hrs daily sunlight illumination and culture duration was 16 days. Each treatment was replicated three times. Results on analysis for bioactive compounds showed that carotenoids, phenols and chlorophylls a and b were detected in the biomass of C. vulgaris signifying a good fish food source. High protein (32.41%), ash (30.33%) and metabolizable energy (262.12Kcal/g) were recorded. The treatment group containing 30kg poultry manure had the highest cell density (19.67ml/l), biomass productivity (1.82ml/l), growth rate (3.52g) and substrate consumption percentage (49.99%). This concentration provided excellent and sustainable conditions that enabled C. vulgaris multiplication. While the 10 and 20kg treatment groups recorded lower growth resources, higher concentrations of 40 and 50kg showed light penetration problems. The 30kg pure poultry manure quantity is therefore recommended for the culturing of green algae, C. vulgaris which could be used as feed supplement in the culture of Clarias gariepinus.