Selenium requirement in Norwegian pig production

The project with the title ?Selenium requirements in Norwegian pig production? is a so called KPN project (competence project for the industry sector). Norwegian farmers and veterinarians have reported problems with clinical signs that may be related to selenium (Se) and/ or vitamin E (vit E) deficiency. This occurrs despite Se and vit E concentrations in feed according to recommendations and maximal allowed concentrations in pig feed. Inorganic (sodium selenite) and organic Se sources (Se yeast and L-SeMet) were tested in multiple field trials on sows, offspring and finisher pigs. Results from one of the finisher pig trials was published in Journal of Trace Elements in Medicine and Biology in 2018. The remaining publications are currently in progress. In general, L-SeMet showed beneficial effects on Se storage in pigs, on inflammatory and immune related gene expression and the selenoprotein quantities (SePP) in porcine plasma samples. A potential dietary effect on DNA integrity was found. The results from this project has provided important information on the effects of different Se sources and -levels in feed on the pigs Se status and health.

Today, an increasing number of Norwegian pig producers experience problems that may be caused by selenium (Se) or vitamin E (vit E)deficiency. A scientifically based statement has been requested from the Norwegian pig industry regarding porcine Se supplem entation since no recent research results are available. In 2011, Animalia conducted a survey among Norwegian veterinarians which revealed a countrywide sporadic occurrence of symptoms believed to be caused by Se/ vit E deficiency, mainly affecting fast g rowing, feed efficient pigs. Symptoms occurred even if the feed contained Se up to the maximum allowed level of 0.5 mg/ kg and vit E levels of more than 100 mg/ kg. Consistency between clinics, necropsy and trace element analysis was lacking. The typical pathological picture in muscular tissues could be present along with Se values in tissue and feed within what has been widely considered sufficient. Additionally, recent field reports describe sows showing Se-/ vit E-deficiency symptoms. Necropsy revealed skeletal muscle and myocardial degeneration as well as liver necrosis. Use of organic Se supplements in pig feed has been reported to improve Se-retention in muscles and to increase the Se concentrations in sow milk and improve the piglet Se status. Can organic forms of Se increase muscle and milk Se concentrations and reduce these health problems potentially related to Se deficiency? Pigs low in Se may have impaired immune responses and have shown higher susceptibility to infectious diseases. Sufficien t Se may be particularly important for the immunological health of piglets through the demanding weaning period. Is the need for Se in rapidly growing and feed efficient pigs higher than allowed by Norwegian and international legislation? More basic resea rch is needed to properly assess the Se requirement in pigs of today. An interdisciplinary research approach should provide solid answers to these questions of great importance for Norwegian pig production