Evaluation of Humic Acid Supplementation in Diet for Improve Health Intestine Status of Asian Seabass Lates calcalifer When Fed Diet with Green Mussel Perna viridis Meal Contaminated Low Cadmium (Cd) as a Feed Ingredient Model

This study aims to assess how the humic acid (HA) supplementation in the diet of Asian seabass (Lates calcarifer) affects the intestinal health of fish when given a diet containing green mussel (Perna viridis) meal contaminated low cadmium (Cd). Five types of test feed, consisting of natural and synthetic humic acid (NHA and SHA), with doses of 0, 0.16% (SHA), 0.16%, 1%, and 2% (NHA). Twenty-five fish (4.18±0.25 g) were kept in an aquarium with a volume of 62 liters of water in a recirculation system for 70 days. The result of the study that green mussel meal can be used as an ingredient in Asian seabass by complementing HA. HA at a concentration of 0.16% in feed affects intestinal health, digestibility, and fish growth. HA helps reduce Cd toxicity by increasing antioxidant levels and reducing malondialdehyd, a biomarker of oxidative stress, in the fish's gut. High NHA supplementation at dosages of 1% and 2% in the diet decreased fish growth. The conclusion was that supplementing 0.16% of HA in the diet could improve intestinal health and growth performance in fish Asian seabass when fed a diet with green mussel meal contaminated Cd as a feed ingredient model. Keywords: cadmium, feed additive, green mussel meal, humic substance.