Goji Berry (Lycium barbarum) Supplementation during Pregnancy Influences Insulin Sensitivity in Rabbit Does but Not in Their Offspring

SIMPLE SUMMARY: Diabetes mellitus is a disorder affecting millions of people worldwide. History of gestational diabetes is a proven risk factor, while diet may be a strategy for its prevention. Goji berry is the fruit of Lycium barbarum and a traditional medicinal herb with potential antidiabetic and hypoglycemic effects. This study evaluated the effect of two doses of Goji berry dietary supplementations on insulin sensitivity in rabbit does during pregnancy by using fasting and intravenous glucose tolerance test-derived indices. A long-term effect on the offspring was also hypothesised. The rabbit was a good experimental model for this study of insulin sensitivity as the tolerance test was feasible and sensitive to dietary modifications. The higher dose of Goji berry supplementation reduced the maximum glucose concentration after bolus administration, suggesting an improvement in the insulin response. Conversely, the present study could not support the effect of maternal diet on the adult offspring’s insulin sensitivity. The use of nutraceuticals as well as the hypothesis of foetal programming of metabolic diseases deserve further study. ABSTRACT: This study investigated the effects of Goji berry (Lycium barbarum) dietary supplementation during pregnancy on insulin sensitivity of rabbit does and their offspring. Starting from two months before the artificial insemination, 75 New Zealand White does were fed only commercial standard diet (C) or supplemented with 1% (G1) and 3% (G3) of Goji berries. Their offspring received a standard diet but kept the nomenclature of the mother’s group. Fasting and intravenous glucose tolerance test-derived indices were estimated at 21 days of pregnancy on rabbit does and at 90 days of age on the offspring. No difference was found in the fasting indices, while the diet modulated the response to glucose load of rabbit does. In particular, G3 group had the lowest glucose concentrations 5 min after the bolus administration (p < 0.05) and, as a result, differed in the parameters calculated during the elimination phase such as the elimination rate constant (K(el)), the half-life of the exogenous glucose load (t(1/2)), and apparent volume of distribution (V(d); for all, p < 0.05). The high dose of Goji supplementation could thus enhance the first-phase glucose-induced insulin secretion. Findings on the offspring were inconsistent and therefore a long-term effect of Goji supplementation during pregnancy could not be demonstrated. Further study on the effect of Goji on the secretory pathway of insulin could clarify its hypoglycaemic action, while different protocols are needed to investigate its potential effects on foetal programming.