Addition of essential oil from lemongrass to the tambaqui ( <i>Colossoma macropomum</i> ) diet: Effects on growth, intestinal enzymes, haematological and metabolic variables, and antimicrobial challenge
Carlos Eduardo Copatti, Altiery Felix e Silva, Vitor Prates Lorenzo, Mateus Matiuzzi da Costa, José Fernando Bibiano Melo
Abstract
Abstract This study evaluated the effect of dietary addition of essential oil from lemongrass ( Cymbopogon citratus ) (EOCC) on growth, intestinal enzymes, biochemical and haematological variables, and survival after Aeromonas hydrophila infection in tambaqui ( Colossoma macropomum ) juveniles. Five diets with different levels of EOCC—0.0 (control), 0.25, 0.50, 1.00 and 1.50 ml kg diet −1 —were evaluated for 60 days, followed by 15 days of bacterial infection. The major chemical compound of EOCC was α‐citral (73.55%). There were no differences in fish survival. Supplementation of 0.25 or 0.50 ml EOCC kg diet −1 increased weight gain ( p = 0.034). In general, haematological variables were increased in the treatment 0.25 ml EOCC kg diet −1 ( p < 0.05). As the EOCC concentration in the diet increased, plasma glucose, albumin, total cholesterol levels and hepatic somatic index were decreased, and plasma total proteins and muscle glycogen levels were increased ( p < 0.05). In tambaqui fed 0.50 ml EOCC kg diet −1 , there were increased hepatic glycogen levels ( p < 0.016) and intestinal alkaline protease activity ( p = 0.049). In conclusion, up to 0.50 ml EOCC kg diet −1 could improve growth performance, haematological variables, muscle glycogen levels and intestinal alkaline protease activity in tambaqui but did not affect fish survival after A. hydrophila infection.