Chlorella vulgaris and Dunaliella salina-enriched Artemia salina enhances growth, pigmentation, gut morphology and immune-related pathways in goldfish (Carassius auratus)

The objective of this research was to investigate the impacts of supplementing both unenriched and enriched live Artemia salina with Chlorella vulgaris and Dunaliella salina in goldfish (Carassius auratus) diets on various parameters, including growth performance, feed utilisation, blood parameters, immunity, histology, and β-carotene levels. The experiment was conducted for 90 days, and all groups of goldfish (initial weight = 2.51 ± 0.01 g/fish, N = 180) received commercial diet supplements (unenriched Artemia (UE), Chlorella-enriched Artemia (CE), Dunaliella-enriched Artemia (DE), and Artemia enriched with both Chlorella and Dunaliella (CDE)). Compared to other fish groups, goldfish given CDE had better final weight, weight gain, average daily gain, specific growth rate, relative growth rate, final length, and length gain, and a lower feed conversion ratio. CDE had the best hematological, antioxidant, and immunity parameters (Immunoglobulin M levels, lysozyme activity, phagocytic activity, and phagocytic index). In addition, goldfish given CDE had the greatest β-carotene content at 8.90 ± 0.4 mg/100 g. Goldfish given enriched Artemia, specifically CDE, exhibited increased intestinal villus length, width, and goblet cells, as determined by histomorphometric analysis (p < 0.05). Additionally, upregulation of MCH, MCH-R, POMC, IGF-1, and TNF-α genes was observed in CDE. In conclusion, supplementing goldfish diets with CDE has several advantages, including improved growth performance, blood parameters, immunity, histology, β-carotene levels, and gene expression related to growth and immunity. The study's results indicate that Artemia enhanced with Chlorella and Dunaliella can improve the health, growth performance, and development of goldfish in aquaculture.