<b>Zinc-amino acid complex in practical diets for Nile tilapia (<em>Oreochromis niloticus</em>)</b> - DOI: 10.4025/actascianimsci.v26i4.1716

Abstract

Commercial diets for fish culture are supplemented with an inorganic zinc sources. Zinc oxide (ZnO) is the most utilized Zn supplementation in Brazil. However, organic metal complexes may increase mineral absorption in the digestive tract. Based on this knowledge, the effects of a amino acid zinc complex (Zn-AA) upon growth performance and carcass composition of Nile tilapia, Oreochromis niloticus L., fingerlings, were compared to the ones observed for ZnO. Isoproteic and isoenergetic soybean meal/corn-based diets were offered to fish for 75 days, supplemented with 30, 90, 150 or 210mg Zn/kg, from ZnO or Zn-AA. Fish (1.79 ± 0.10g) were allocated in thirty six 250-L tanks, and fed ad libitum four times a day. Fish fed with ZnO-supplemented diets, regardless of the supplementation level, showed a significantly higher weight gain than the animals fed with Zn-AA-supplemented diets (P<0.05). Besides, food conversion and protein efficiency ratio of fish fed with ZnO were significantly better than the verified for fish fed with Zn-AA-supplemented diets. The proximal composition of fish carcasses was statistically similar (P>0.05) for different experimental treatments. The experiment showed that Zn-AA supplementation produced worse fish growth performance than ZnO.