Impact of goji berries (Lycium barbarum) supplementation on the energy homeostasis of rabbit does: Uni‐ and multivariate approach

This study examined the effects of goji berries dietary supplementation on the energetic metabolism of doe. Thirty days before artificial insemination, 75 New Zealand White does were assigned to three different diets: commercial standard diet (C) and supplemented with 1% (LG) and 3% (HG) of goji berries, respectively. Body conditions, hormones and metabolites were monitored until weaning. Body weight and BCS were higher in HG than C (p < 0.05). LG showed lower T3/T4 ratio and cortisol concentrations (p < 0.05) and tended to have lower indices of insulin resistances (p < 0.1) than HG. Compared to control, leptin was higher in HG at AI (p < 0.01) and in LG during lactation (p < 0.05). Two principal components were extracted by multivariate analysis describing the relationships between (1) non‐esterified fatty acids, insulin and glucose levels, and (2) body conditions and leptin metabolism. The first component highlighted the energy deficit and the insulin resistance of the does during pregnancy and lactation. The second one showed that leptin, body weight and Body Condition Score (BCS) enhance as levels of goji berries in the diet increase. Thus, the effects of goji supplementation are dose‐dependent: an improvement on energy metabolism was achieved with a low‐dose while the highest dose could determine excessive fattening and insulin resistance in does.