Relationship of selenium-dependent glutathione peroxidase activity and nutritional pancreatic atrophy in selenium-deficient chicks.

Experiments were conducted to determine the relationship of selenium-dependent glutathione peroxidase (SeGSHpx) activity to the onset of nutritional pancreatic atrophy (NPA) in chicks. Chicks produced from hens fed a low Se, low vitamin E practical diet had low activities of SeGSHpx in plasma and pancreas at hatching. The SeGSHpx activity remained at a low level before and during all stages of the onset of NPA. Selenium supplementation of the diet prevented NPA and resulted in significant elevations in SeGSHpx activity. Although the early stages of NPA are believed to involve mitochondrial swelling, no significant differences were found in rate of oxygen uptake, respiratory control index or adenosine diphosphate to oxygen ratio between pancreatic mitochondria isolated from Se-deficient or Se-adequate chicks. Improvements in maternal Se status significantly increased chick pancreatic SeGSHpx activity at hatching and delayed the onset of NPA in chicks fed a Se-deficient diet. A significant proportion of the second-generation Se- and vitamin E-depleted chicks used in these studies was found to grow at nearly normal rates when fed the Se-deficient diet. These chicks, designated as refractory to the growth-depressing effect of severe Se-deficiency, were biochemically deficient (i.e., had very low SeGSHpx activities) and showed NPA. It is concluded that the Se-responsive lesion which results in NPA in the chick is different from that which results in depressed growth.