Physiological properties of liver, gonads and muscle during maturation of female Atlantic salmon, Salmo salar. Comparison between a control and xenobiotics containing fish feed.

1. Atlantic salmon, Salmo salar, in their 4th year were maintained in a sea-based farm in the Baltic Sea, salinity 0.2-0.4%. The fish were fed a control diet or a diet containing, among the lipid-soluble xenobiotics, 60 parts of dioxin per 10(12) parts of fish oil. 2. In the fish that attained sexual maturity the liver and gonadal wet weight increased, but decreased after stripping of the roe. Vitellogenesis was also apparent as an elevated level of plasma vitellogenin which was higher after than 2 months prior to removal of the roe. 3. In muscle protein content was highest prior to the removal of the roe. RNA content decreased with time. Following the taking of the roe glycogen content and acid proteinase activity were elevated. 4. Comparison between the feeding groups showed, in the fish fed the experimental diet, a higher gonadal wet weight and plasma vitellogenin content, and in muscle, after stripping of the roe, a lower glycogen content and an elevated level of acid proteinase activity.