| Summary: | To rear cleaner fish together with Atlantic salmon (Salmo salar) is a biological strategy to keep sea lice away from the salmon. Ballan (B) wrasse (Labrus bergylta) and lumpfish (Cyclopterus lumpus) are the two species being farmed in Norway for this purpose. To support a rapid rise of cultivation scale, present knowledge needs strengthening, and in this context, in particular regarding their nutritional biology. Among the many aspects of biology, investigation of digestive physiology and nutrient requirement is necessary to be able to produce feed which supports good growth and high survival. Regarding B. wrasse, a stomach-less fish with short intestine, research conducted until the time of initiation of this PhD work had addressed some aspects of nutrient requirements, the suitability of some plant ingredients as nutrient sources, and the importance of feed consistency. Although some efforts had been made to describe the digestive system of the B. wrasse, essential information was still missing. For lumpfish, a fish with stomach and many pyloric caeca, hardly any knowledge on digestive physiology, nor on nutrient requirement was available. Therefore, the strategy and goal of this PhD work was to strengthen knowledge and understanding on digestive physiology and diet effects on intestinal functions and health in B. wrasse and lumpfish to secure good growth and health. To achieve this, the following strategies and goals were chosen for the present studies of B. wrasse (point 1 and 2) and lumpfish (point 1 and 3): 1. To characterize aspects of intestinal morphology and functions and effects of variation in diet composition for optimization of diet composition in accordance with the biology of the fish. 2. To describe effects of saponins which may occur in plant ingredients and may induce inflammation in the intestine and possible preventive effects of prebiotics. 3. To investigate effects of diet composition on disease resistance. The work in Paper I was carried out to profile key characteristics of intestinal ...
|
|---|