Temporal changes in sphingolipids and systemic insulin sensitivity during the transition from gestation to lactation

Area of Science:

• Metabolic physiology
• Lipid metabolism
• Dairy cattle health

Background:

• Reduced insulin action is normal during the peripartum for nutrient transfer.
• In overweight dairy cows, excessive insulin resistance and lipolysis can lead to metabolic disease.
• The role of sphingolipid metabolism in peripartal insulin resistance is not well understood.

Purpose of the Study:

• To analyze temporal changes in plasma and tissue sphingolipids in lean and overweight peripartal cows.
• To determine the relationship between sphingolipid levels, lipolysis, liver lipid accumulation, and insulin sensitivity.

Main Methods:

• Longitudinal study of 21 multiparous Holstein cows (lean and overweight) from 21 days prepartum to 21 days postpartum.
• Profiling of plasma, liver, and skeletal muscle sphingolipids using LC/MS/MS.
• Assessment of insulin sensitivity via intravenous insulin and glucose challenges.

Main Results:

• Insulin resistance, lipolysis, and liver lipid accumulation increase postpartum.
• Ceramides and glycosylated ceramides accumulate during the peripartum, elevated in overweight cows.
• Ceramide accumulation correlates with lipolysis and liver lipids; specific ceramides inversely correlate with postpartum insulin sensitivity.
• Plasma sphingomyelin levels decrease at parturition and associate with feed intake.
• Overweight cows exhibit lower peripartal plasma sphingomyelin levels.

Conclusions:

• Dynamic peripartal changes in sphingolipids are influenced by adiposity and linked to the onset of insulin resistance.
• Sphingolipids may play a role in the physiological adaptations to the peripartum period in dairy cows.