Unlocking Growth, Nutrition, and Pigmentation Potential of Chlorella sp., and Gonyostomum sp. Cultured in Cost-Effective, Biological Waste-Based Media

Microalgae are highly nutritious and fast-growing organisms that are utilized in aquaculture as premix for feed formulation and as live feed for the larvae culture industry. The aim of the research was to reduce live feed production costs for aquaculture through the utilization of cow dung as a biological waste. This research reports on the growth, pigments, and nutritional contents of two marine microalgal species (Chlorella sp., and Gonyostomum sp.). Each of the microalgae was cultured in four treatments: C (control, conway medium), T1 (50% conway, 50% cow dung), T2 (25% conway, 75% cow dung), and T3 (100% cow dung). The outcomes exhibited that the C treatment of Chlorella sp. and T1 treatment of Gonyostomum sp. had the highest growth in terms of cell density. Moreover, both species had significantly higher (p  < 0.05) protein percentage in C which were 42.7% ± 4.03%, and 42.9% ± 1.96%, respectively, and greater total lipid and carbohydrate contents in either T1 or T2 treatment. Gonyostomum sp. exhibited the highest carotenoid content (2.48 ± 0.09 µg/mL) in C, while Chlorella sp. had significant amount of total phycobiliprotein contents in all treatments compared to Gonyostomum sp. Although polyunsaturated fatty acid (PUFA) contents were higher in conway medium, both of the microalgae in T1 and T2 treatments had high saturated fatty acids (SAFA) and monounsaturated fatty acid (MUFA) contents. Furthermore, both species had notable concentrations of nonessential amino acids in comparison to essential amino acids. The cost estimation confirmed C had the highest preparation cost compared to other treatments.