Carbohydrates are considered to be the most economical energy source in feed due to its wide source, low price and protein-saving effect. Adding high levels of carbohydrates to feed is favoured by the aquaculture industry, as it usually reduces feed cost coupled with an improvement of the pelleting quality (Romano & Kumar, 2019).However, unlike terrestrial animals, it is commonly believed that fish (especially carnivore ones) are usually glucose intolerant and show a poor ability to use carbohydrates for energy (Krogdahl, Hemre, &