Norsvin's Dr. Maren Moe successfully defended her doctoral theses this week. The last 4 years Dr. Moe has been working on a Norsvin project addressing the genetics behind boar taint.

Since 2002 Norwegian farmers have not been allowed to castrate male piglets themselves. Castration has to be performed by a qualified veterinarian using anesthesia. In 2011, a new legislation banning the practise of castration will be in place, increasing emphasise on different approaches to avoid the problem caused by boar taint of intakt boars.
Norsvin invests heavily in research and development. The project Dr. Moe is working on is one of many which in turn can lead to increased profit for the swine industry. Cost related to the castration of boars is significant, and boars grow faster and utilize feed more efficient than barrows. Norsvin congratulates Dr. Moe with her successes in gathering new and important knowledge on this subject – and of course with her new degree!

Boar taint is primarily caused by elevated levels of androstenone and/or skatole in the adipose tissue. Androstenone is a steroid produced in testis and degraded in liver, and the levels of androstenone are highly influenced by genetics. Skatole is a metabolic product of the amino acid tryptophan and is absorbed from the gut and metabolised in liver. Levels of skatole are also influenced by genetics, but can to a certain extent be regulated by environmental factors.

Selection is proposed as one of the most realistic approaches for reducing levels of boar taint. Unfavourable correlations between boar taint compounds and phenotypes related to reproduction might, however, influence the fertility of pigs. It is therefore important to understand the complex genetic system controlling boar taint before starting selection.

When this project started, molecular genetic studies worldwide had focused on a limited number of genes only. To achieve a better understanding of the genetics of boar taint, Dr. Moe and her team, applied different approaches that complement each other and made a complete picture of the genetic factors involved in boar taint. Gene expression profiles in testis and liver from boars with extreme high and low levels of androstenone were studied to identify new candidate genes and pathways associated with boar taint. Hundreds of novel genes were successfully discovered using this method and we also established breed specific differences between Norsvin Landrace and Duroc boars in the expression of several of these genes. Moreover, single nucleotide polymorphisms (SNPs) were detected in some of the candidate genes and these SNPs were associated with levels of boar taint compounds to identify possible genetic markers. The SNPs were furthermore associated with levels of testosterone, estrogens and length of bulbo urethralis gland, which are all phenotypes related to reproduction and sexual maturity in the pigs. Favourable SNPs had the combinatorial effect of reducing levels of boar taint compounds without significantly affecting levels of phenotypes related to reproduction, and altogether six genes had SNPs with such an effect. Protein expression analysis was also performed to verify the expression of key genes on the protein level. Dr. Moe found breed specific differences between Norsvin Landrace and Duroc boars for the expression of two proteins involved in metabolism of androstenone.
Selection is proposed as one of the most realistic approaches for reducing levels of boar taint. Unfavourable correlations between boar taint compounds and phenotypes related to reproduction might, however, influence the fertility of pigs. It is therefore important to understand the complex genetic system controlling boar taint before starting selection.

When this project started, molecular genetic studies worldwide had focused on a limited number of genes only. To achieve a better understanding of the genetics of boar taint, Dr. Moe and her team, applied different approaches that complement each other and made a complete picture of the genetic factors involved in boar taint. Gene expression profiles in testis and liver from boars with extreme high and low levels of androstenone were studied to identify new candidate genes and pathways associated with boar taint. Hundreds of novel genes were successfully discovered using this method and we also established breed specific differences between Norsvin Landrace and Duroc boars in the expression of several of these genes. Moreover, single nucleotide polymorphisms (SNPs) were detected in some of the candidate genes and these SNPs were associated with levels of boar taint compounds to identify possible genetic markers. The SNPs were furthermore associated with levels of testosterone, estrogens and length of bulbo urethralis gland, which are all phenotypes related to reproduction and sexual maturity in the pigs. Favourable SNPs had the combinatorial effect of reducing levels of boar taint compounds without significantly affecting levels of phenotypes related to reproduction, and altogether six genes had SNPs with such an effect. Protein expression analysis was also performed to verify the expression of key genes on the protein level. Dr. Moe found breed specific differences between Norsvin Landrace and Duroc boars for the expression of two proteins involved in metabolism of androstenone.