Today, January 6th, Johanna Henny Wagnerberger defended her master thesis. Johanna has been a Master student at CIGENE, under the supervision of Simen Rød Sandve.
Her thesis investigated the functional role of the gene abcg2b in mid-intestine enterocytes of Atlantic salmon. This gene has shown a correlation to variation in flesh colour in Atlantic salmon. Johanna used CRISPR mediated abcg2b knockout salmon and compared the lipid content in their mid-intestine villi to the lipid content in villi of wild-type salmon. Astaxanthin is a pigment with red-orange colour, that is used as a feed additive to salmon to improve the colour of the flesh. Since astaxanthin is lipid-soluble, an increased amount of lipids would suggest an increased amount of the colour donating pigment as well. The difference in lipid content between CRISPR and wild salmon was highly significant, with more than twice as high lipid coverage in knockout salmon villi compared to wild type salmon villi. This suggests that abcg2b exports lipids back into the intestinal lumen, thereby leaving less astaxanthin to be deposited in the muscle, which in turn contributes to a paler flesh. The picture above shows microscopy image of a knock out villi.
Congratulations to Johanna for excellent work and for finalising her master thesis!