Dietary Energy Levels from Middle to Late Gestation of Guangdong Small-Ear Spotted Pig: Effects on Body Weight, Muscle Development, and Glucose Metabolism of its Newborn Piglets

Abstract

Background: Guangdong Small-ear Spotted pigs are Chinese indigenous pig that have the characteristic of desired meat quality and resistance to coarse feeding. However, no study has elucidated the effects of dietary energy levels on body weight, muscle development and glucose metabolism of its newborn piglets. Therefore, a total of 66 pregnant gilts with an average body weight of 80.6±6.6 kg at day 60 of gestation were randomly divided into two groups: control group (CON group; 11.50 MJ/kg digestible energy), and high-energy diet group (HE group; 13.42 MJ/kg digestible energy). Results: The results showed that the maternal HE diet was shown to decrease the birth weight of piglets that from the gilts with total or alive litter size of 12 to 13. Additionally, the HE diet group were shown to impair the glucose tolerance of newborn piglets, as evidenced by the glucose tolerance test and the inhibition of insulin signaling pathway in liver and soleus muscle. Despite no significant change in the muscle weight in the two groups, the maternal HE diet was shown to downregulate the protein level of slow-twitch fiber myosin heavy chain I (MyHC I), and upregulate the protein levels of fast-twitch fiber myosin heavy chain IIb (MyHC IIb) and IIx (MyHC IIx) in soleus muscle of their progeny. Furthermore, the newborn piglets in HE group were showed a decrease in mitochondrial biogenesis in liver and soleus muscle when compared to that in CON group. Conclusions: Maternal high-energy diet from middle to late gestation decreases the birth weight of piglets that from the gilts with total or alive litter size of 12 to 13, induces the formation of glycolytic muscle fibers, and impairs glucose tolerance of their newborn piglets.