Sex differences of serum lipid profile in novel microminipigs

Swine have been used extensively in biomedical research, with a significant increase in recent decades. Minipigs are increasingly becoming an especially attractive animal model in life science research because of their physiological and anatomical similarities to humans. The Microminipig (MMPig) has emerged as a novel and small minipig for non-clinical pharmacological/toxicological use. The MMPig is docile, weighs less than 10 kg in early maturity, and has an easily manageable size. In this study, we report on sex and age patterns in serum biochemistry parameters, including lipid analysis items and lipid profiles in healthy MMPigs. In total, 58 males and 67 females aged 0-34 months underwent serum biochemistry parameter measurements. Most parameters showed no effect of age or sex (although some did). Lipid analyses showed that the serum levels of total cholesterol, but not those of triglycerides (TG), were consistently higher in females at 0-34 months of age. Lipid profiles in 5-month-old MMPigs were investigated in greater detail. Serum low-density lipoprotein-cholesterol (LDL-C) values were higher in females. The percentage of LDL-C against total cholesterol was also higher, although high-density lipoprotein-cholesterol was lower, in females. There were no sex differences in the TG fraction. Although the sex difference in the serum lipid profile remains unexplained, the reference values obtained in this study could help facilitate the use of MMPigs in life science research.