Gastric emptying in cod, Gadus morhua L.: effects of food particle size and dietary energy content

Whole herring, Clupea harengus , were digested and emptied from cod stomachs much more slowly than meals of minced herring, showing that prey integrity is an important factor controlling emptying. Increasing the energy content of the minced herring by addition of fish meal and oil led to a reduction in the percentage of the meal emptied in the 24 h subsequent to feeding, but rates of energy throughput on the enriched herring diet were high. The physical form of the diet appears to be more important than energy content in the control of gastric emptying in cod. The results are discussed with respect to possible effects of dietary type on absorptive and metabolic processes.