Effect of incubation temperature on carbohydrate digestion in important teleosts for aquaculture

The activity and capacity (activity tissue weight) of digestive carbohydrases (total carbohydrase, aglucosidase, a-amylase) was examined in vitro under a range of (more realistic) incubation temperatures (5, 18 and 25 1C) and pH (7.6) more likely to be encountered during rearing, along the digestive tract of important teleost species for aquaculture (Dicentrarchus labrax, Sparus aurata, Oreochromis aureus, Oncorhynchus mykiss and Salmo salar). Results indicate, among other things, an overestimation of digestive carbohydrase levels when performing assays at 37 1C, a di¡erent e¡ect of temperature on digestive enzyme performance along the digestive tract of examined species, and the increased importance of a-glucosidase towards carbohydrate digestion. Implications regarding the capacity of each species for carbohydrate digestion in nature, as well as feed manufacturing, are discussed.