Fibre in late gestation gilt diets, glucose tolerance, and feed intake and bodyweight loss during subsequent lactation

Abstract

Forty-nine crossbred gilts were fed one of three diets during the last month of their gestation: 2.5 kg of a standard diet (2.5C, n = 15), 3.5 kg of the same standard diet (3.5C, n = 17), or 3.5 kg of a high fibre diet, with 10.6% fibre compared with 4.4% fibre in the standard diet (3.5F, n = 17). The 3.5F and 3.5C gilts were fed at isocaloric and isonitrogenous levels. During the subsequent lactation, all gilts were fed the same lactation diet. Nineteen gilts (6 or 7 per treatment) were subjected to an oral glucose tolerance test around Day 110 of gestation. The high feed level (3.5C and 3.5F) resulted in a higher weight gain during gestation (P < 0.05). Gilts fed the high fibre diet tended to have (P < 0.10) piglets with a greater birthweight at farrowing (1535 g) than gilts fed the standard diet at 2.5 kg (1484 g). The 3.5C gilts (n.s.) and the 3.5F gilts (P < 0.05) had a lower feed intake and more bodyweight loss during lactation than gilts fed the 2.5-kg standard diet during gestation. Insulin profiles after the glucose tolerance test were higher for gilts fed the high fibre diet. Gilts fed the 2.5- or 3.5-kg standard diet had a similar insulin profile. Glucose profiles and insulin sensitivity were similar across treatments. Leptin around Day 110 was negatively correlated with feed intake during the third week of lactation (r = –0.28; P < 0.05). This study shows that a high feed level during late gestation reduces feed intake during lactation and that a high fibre diet during gestation does not negate this effect. The results suggest that feed level during gestation and the resulting body fat mass, rather than glucose tolerance, impacts on feed intake during lactation.