Dietary mannanoligosaccharide influenced feed consumption and gut morphology of Nile tilapia raised in net-cage systems

Abstract

This work was set out to determine the effects of increasing levels of dietary mannanoligosaccharides (MOS) on growth and intestine morphology of Nile tilapia. Individuals (12.3 ± 0.3 g) were randomly distributed into 16 net-cages (250 L; 20 fishes per net cage) at Salto Caxias Hydroelectric reservoir in Jacutinga river, Paraná, Brazil, and fed during 60 days with a commercial diet supplemented with 0.0; 0.2; 0.4 and 0.8% dietary mannanoligosaccharides (n = 4). Fish feed consumption showed quadratic correlation with dietary levels of prebiotic at 30 and 60 days. Intestinal villi height was increased in fishes fed with 0.4% dietary MOS for 30 days. However, after 60 days, fishes fed with control diet showed significant increase in villi height. On the other hand, none of the levels of mannanoligosaccharides tested had shown efficiency on growth parameters. In conclusion, the prebiotic had improved the vilosity height of the gut epithelium, even though, no effects were observed on the growth parameters of the Nile tilapia.