Changes in daylength and temperature from April until August for Atlantic salmon (Salmo salar) reared in sea cages, increase growth, and may cause consumption of antioxidants, onset of cataracts and increased oxidation of fillet astaxanthin

The hypothesis of the present study was that increased growth in spring, stimulated by increasing temperature and daylength, leads to oxidative stress Atlantic salmon with accumulation oxidation products tissues utilization antioxidants. drop fillet pigmentation astaxanthin, often observed spring industry, could be explained stress. Furthermore, may cause production related diseases such as development cataracts melanin spots fillet. We sampled from two cages a commercial scale experiment Northern Norway (67°N), every month April until August then second December (510 ± 160–3060 510 g, mean weight std). specific rate (SGR) midsummer decreased thereafter. found vitamin E C liver were depleted restored autumn, even though dietary concentrations stable. Astaxanthin concentration muscle constant during summer concomitant an increase astaxanthin supplementation. Cataract zero May July, when 90% fish affected. glutathione based redox-potential lenses became more reduced June, indicating protective mechanism against cataract. number high June October, but size intensity remaining same period. change concentrations, cataract metabolism early summer, indicate oxidized this period, while malon-di-aldehyde (MDA) did not support hypothesis. There are too few data draw conclusions on possible effects spots.