Yeast cell wall (YeaMOS) is a natural product contain 1,3 – 1,6 chain of beta glucan which can enhance the immunity of aquaculture. Besides enhancing the immunity, it also can regulate the intestinal microflora, indirectly affect positively on the health. Yeast cell wall also contain mannan oligosaccharides (MOS) which can agglutinate pathogen and prevent them to bind to the gut receptors. Hydrolysed yeast (Gropro) which is a functional protein, able to provide external nucleic acid to young animals, helping them to grow and develop intestine and get through the critical early growth stages. In addition, hydrolysed yeast also can replace part of the fish meal and increase the feed palatability.