Carbohydrate utilization by rainbow trout is affected by feeding strategy

Area of Science:

• Aquaculture
• Fish Nutrition
• Animal Science

Background:

• Rainbow trout (Oncorhynchus mykiss) growth is influenced by diet composition and feeding strategies.
• Understanding carbohydrate utilization is crucial for optimizing aquaculture diets.

Purpose of the Study:

• To compare the utilization of glucose, maltose, dextrin, and raw cornstarch in rainbow trout.
• To evaluate the impact of continuous versus meal feeding strategies on trout growth and nutrient utilization.

Main Methods:

• A 16-week feeding trial with rainbow trout (initial weight 5.5 g).
• Fish were fed four carbohydrate sources (32 g/100 g diet) either continuously or four meals daily at 2.0% body weight/day.
• Measurements included growth performance, feed efficiency, body composition, liver glycogen, and lipogenic enzyme activities.

Main Results:

• Continuous feeding significantly improved specific growth rate, final body weight, feed efficiency, and nutrient retention compared to meal feeding.
• Trout fed glucose or maltose showed better growth and nutrient utilization than those fed starch.
• Continuous feeding enhanced lipogenic enzyme activities and lipid storage, particularly with simple sugars.

Conclusions:

• Continuous feeding optimizes carbohydrate utilization and promotes lipid deposition in rainbow trout, especially under restricted feeding conditions.
• Simple sugars (glucose, maltose) are utilized more efficiently than complex carbohydrates (starch) by rainbow trout.
• Feeding strategy significantly interacts with carbohydrate source to influence fish performance and metabolism.