Influence of Castration-induced Sex Hormone Deficiency on Serum Lipid Levels and the Genes Expression in Male Pigs

Abstract

It has been known that the changes in gonadal steroids are closely associated with adipose tissue metabolism. Domestic pigs have been a well-recognized experimental animal in biomedical research because of their similarity to humans in body size and other physiological/anatomical features. The aims of this study were to investigate the influence of castration-induced sex hormone deficiency on serum lipid levels and the genes expression of key enzymes associated with lipogenic and lipolytic processes in male pigs. The experimental animals consisted of 2 groups slaughtered on 147th and 210th day, respectively. In each of the group, 7 full-sib pairs of castrated and intact male hybrids from Yorkshire dams sired by Landrace were contained. The results showed that castration of male pigs led to increased total cholesterol, triglyceride, high density lipoprotein, low density lipoprotein, and leptin levels in serum (p<0.05). No differences in levels of the free fatty acid, insulin, and glucose were observed between boars and barrows (p>0.05). Castration caused upregulation of fatty acid synthase and acetyl-CoA carboxylase alpha genes expression at both 147 and 210 days of age (p<0.05). No differences in expression of hormone sensitive lipase and adipose tissue triglyceride lipase genes were observed between boars and barrows at either 147 or 210 days of age (p>0.05). It is speculated that higher body fat deposition in castrated male pigs might have resulted mainly from increased transcription of the lipogenic genes, but not from decreased transcription of the lipolytic genes.