Development of foraging and digestive function in Atlantic cod (Gadus morhua) larvae in response to diet

Abstract

Atlantic cod (Gadus morhua) show great potential for mass-rearing, but much is unknown about their digestive capacity and efficiency. This thesis provides an integrated study of survival, growth, behaviour, and digestive enzyme activity in cod larvae and the variability in digestive development in response to nutritional quality of live food enrichments. -- Experiments were performed investigating the effect of enrichments with live food. The first experiment used high- and low-lipid rotifers (Brachionus plicatilis) from hatching to 450 dd. Lipid level significantly impacted survival, behaviour and digestive enzyme activity by 100-150 dd. A second experiment examining Artemia franciscana enrichments from 450-650 dd resulted in larvae fed a rotation diet showed the greatest survival and growth rates, but behaviour was not impacted by enrichment type. High-protein and high-lipid diets were able to induce significantly high post-prandial digestive enzyme activities. Results indicate that diet plays a role in growth and survival, but also in the enzymatic activity of the young fish's developing digestive system.