Ginger oil, Zingiber officinale, improve palatability, growth and nutrient utilisation efficiency in Nile tilapia fed with excess of starch

•Ginger acts as appetiser in diets for Nile tilapia.•Ginger improves growth and nutrient utilisation efficiency in Nile tilapia.•Ginger improves nutrient retention in Nile tilapia.•Starch up to 400 g/kg doesn’t hamper productive performance in Nile tilapia.•Ginger improves nutrient utilisation by Nile tilapia fed with excess starch. We aimed to evaluate the effects of ginger, starch, and it’s interaction on nutrient utilisation efficiency and on productive performance of Nile tilapia. Fish were fed diets containing three levels of corn starch inclusion (300, 400 and 500 g/kg) and four levels of ginger oil (0, 0.57, 1.14 and 2.27 ml/kg). Fish fed with 0.57 ml/kg of ginger oil presented increased feed intake and higher growth. Moreover, the 0.57 ml/kg level of ginger oil improved feed conversion rate for fish fed with 500 g/kg starch, when compared to fish fed with the ginger absent diet. Supplementation with 1.14 ml/kg provided increased carcass protein content in fish. Fish fed with 300 and 400 g/kg presented better productive performance than those fed with 500 g/kg starch, beside this, fish fed 400 g/kg starch presented higher content of hepatic glycogen. Ginger oil improves the diet palatability, fish growth, retention of nutrients in the fish carcass, and attenuates the impairment caused by excess starch in nutrient utilisation efficiency. Higher than 400 g/kg dietary starch impairs food intake, growth, and nutrient utilisation efficiency for Nile tilapia.