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Carbohydrates are the least expensive form of dietary energy for animals. Although fish don't have specific requirements for dietary carbohydrates, they must be provided with the appropriate levels of carbohydrates in their diets. Moderate levels of carbohydrate could support fishs' better growth performance and may decrease the use of the more expensive protein and lipids in the diet. Different fish have different ability to utilize digestible carbohydrates, which may relate to the relative amount of amylase activity present in the digestive system of the various species. α-amylase is a key enzyme for carbohydrate digestion. Bluegill, an important forage and recreational as well as a newly emerged food fish, is the most commonly produced sunfish in the North Central Region. Information on the digestive amylase activity and the dietary carbohydrates utilization in Bluegill is lacking. The objective of this study was to determine the distribution of α-amylase activity along the digestive tract of juvenile Bluegill and to compare its activity with slecte fish species. The α-amylase analysis followed Worthington (1993) with a slight modification. α-amylase was detected in the stomach, pyloric cecum, proximal intestine, mid intestine, and distal intestine in Bluegill. The lowest α-amylase activity was found in the stomach. No difference in α-amylase among the three parts of intestine was detected. α-amylase activity in Bluegill along the digestive tract is higher than that in Black Crappie, but significantly lower than that in Grass Carp (p < 0.05). Knowledge of α amylase may provide useful information for estimating the carbohydrates level for juvenile Bluegill diets.

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Aquaculture--Research, Bluegill--Feeding and feeds, Bluegill--Growth, Bluegill--Physiology


Aquaculture and Fisheries

The Distribution of α-Amylase Activity along the Digestive Tract of Juvenile Bluegill (Lepomis macrochirus) and its Comparison with Selected Fish Species