Black garlic (Allium sativum) powder, a promising feed supplementation improves hematological and immunological indices, body composition, and growth performance of golden pompano (Trachinotus blochii)

Abstract

Golden pompano (Trachinotus blochii) is a key aquaculture species in Asia, facing challenges from pathogens in open farming systems. Addressing diseases traditionally through antibiotics and chemicals, the sustainable alternative of using natural immune stimulants is becoming more prevalent. This study focuses on black garlic, a fermented form of fresh garlic (Allium sativum L.), known for higher bioactive compounds, which has not been extensively researched in aquaculture. We investigated the impact of black garlic supplementation in diets on the growth, feed utilization, blood health, enzymatic antioxidants, antibacterial activity, and immune gene expression in golden pompano. A total of 600 fish with an initial average weight of 7.6 ± 0.2 g were assigned to five diets containing 0 (Diet 1), 10 (Diet 2), 20 (Diet 3), 40 (Diet 4), and 80 (Diet 5) g/kg of black garlic over eight weeks. Growth performance metrics such as average length growth (ALG), average weight growth (AWG), specific growth rate (SGR), and feed conversion ratio (FCR) were significantly enhanced, particularly with Diet 4 showing the highest mean weight gain (P < 0.05). Hematological analyses revealed increases in both red and white blood cell counts, with total superoxide dismutase, catalase, and lysozyme levels rising linearly and quadratically, most notably in Diets 4 and 5. Nevertheless, lysozyme gene expression did not show significant changes across the treatments. The results suggest that black garlic at concentrations of 40–80 g/kg in feed can substantially improve growth rates, innate immunity, and antioxidant activity in golden pompano, demonstrating its potential as a beneficial dietary supplement in aquaculture.