Evaluation of the effects of pregnancy on insulin sensitivity, insulin secretion, and glucose dynamics in Thoroughbred mares.

The research article investigates the impacts of pregnancy on insulin sensitivity and glucose dynamics in Thoroughbred mares. It also examines the effects of high-starch and high-fat, high-fiber supplemental feeding on glycemic and insulinemic response in pregnant and non-pregnant mares.

Research Methodology

• The study involved 22 pregnant and 10 non-pregnant Thoroughbred mares, all in healthy condition.
• The researchers administered frequently sampled intravenous glucose tolerance tests at two different times, namely at 25 to 31 weeks of gestation (period 1) and at 47 weeks of gestation (period 2).
• After the period 1 tests, the mares were given either a high-starch (39% starch) or high-fat and -fiber (14% fat and 70% fiber) supplemental feed.
• For a subset of mares (n = 12), hourly blood samples were taken over the course of 24 hours to study their glycemic and insulinemic responses to feeding while in the pasture.

Research Findings

• The pregnant mares during period 1 showed lower insulin sensitivity and glucose effectiveness, and higher acute insulin responses to glucose than nonpregnant mares.
• The insulin sensitivity value decreased in the nonpregnant mares but not in pregnant mares from period 1 to period 2.
• The pregnant mares that were given the high-starch feed showed a higher glycemic and insulinemic response to feeding compared to the other groups.

Conclusions

• The research showed that, at 28 weeks of gestation, pregnant mares had slower glucose clearance and higher insulin secretion as compared to nonpregnant mares.
• Further, the findings indicated that the glucose and insulin responses to meal feeding, specifically with high-starch feed, were greater in pregnant mares, suggesting that pregnancy enhanced the postprandial (after meal) glycemic and insulinemic effects of starch-rich feed supplements.