Starch gelatinization on the physical characteristics of aquafeeds and subsequent implications to the productivity in farmed aquatic animals

Abstract

AbstractStarches are added macronutrients in aquafeeds to act as binders and provide inexpensive digestible energy to aquatic animals. These qualities can be further enhanced through gelatinization, which occurs when the crystalline region of amylopectin within the starch granule melts along with the leaching of amylose to form a gel matrix. This process readily occurs in the presence of heat and water, and therefore, some degree of starch gelatinization is ubiquitous in aquafeeds. When using simple technology, such as hand pelleters that employ less heat, pressure and shear forces, the inclusion of pre‐gelatinized starch can effectively improve pellet quality and digestibility in aquatic animals. In this review, the implications of starch gelatinization to various pellet characteristics will first be presented, followed by a brief discussion on carbohydrate metabolism in aquatic animals. A common feature of gelatinized starch in fish includes a higher digestibility; however, the implications to growth, physiology, post‐harvest quality as well as waste and disease management can depend on the host species, starch type and degree of gelatinization. This review comprehensively discusses these factors in various aquatic animals and such information may assist feed manufacturers and nutritionists to optimize cost‐effective feed formulations.