From d 26 of gestation until farrowing, gilts were fed diets that contained 2.8 or 11.0% crude fiber (control and high-fiber diets, respectively, n = 9/treatment). Gilts were housed individually during the first 5 wk of gestation and then in groups of 4. Daily feed allowance provided the same amount of DE daily (33 MJ of DE/d). Throughout lactation, all sows were allowed to consume a standard lactating sow diet ad libitum. Litters were standardized to 12 piglets beyond 48 h after birth. Sows were weighed on the second and the 105th day of gestation, on the day after farrowing, on d 15 of lactation, and on the day of weaning. Backfat thickness of each sow was measured ultrasonically on these same days. On d 105 of gestation, a jugular catheter was surgically implanted. Preprandial blood samples were collected from d 109 of gestation to the day after farrowing and on d 4, 18, and 26 of lactation. Meal tests and glucose tolerance tests were performed on d 109 of gestation and d 4 and 18 of lactation. Colostrum was collected 1 h after birth of the last piglet. Milk was collected at d 5 ± 1 and d 19 ± 1 of lactation after an injection of oxytocin. Fasting blood samplings were used to analyze plasma concentrations of glucose, lactate, NEFA, urea, and ?-amino nitrogen between the end of gestation and the end of lactation. Hormone assays in blood (Prolactin, IGF-I, and leptin) were measured on single blood samples and insulin on samples from the meal tests and glucose tolerance tests. Hormone assays in colostrum were also measured.
During gestation, BW and backfat gain did not differ between treatment groups. During lactation, sows fed the high-fiber diet ate an average of 0.94 kg/d more than control sows (P < 0.02). Piglets born from sows fed the high-fiber diet grew faster than piglets from control sows (P = 0.03). Sows fed the high-fiber diet during gestation had lesser concentrations of leptin before farrowing than control sows (P < 0.01). Leptin concentrations were negatively correlated with feed intake during lactation (P < 0.05). The prepartal increase in prolactin concentrations tended to be greater in sows fed the high-fiber diet than in control sows (P < 0.1). During lactation, glucose and insulin profiles after a standard meal did not differ between sows from treatment groups.
In conclusion, the greater appetite of lactating sows fed a high-fiber diet during gestation does not seem related to changes in glucose and insulin metabolism. The greater feed consumption was accompanied by a faster growth rate of piglets without sparing effect on maternal body reserves.
H Quesnel, MC Meunier-Salaün, A Hamard, R Guillemet, M Etienne, C Farmer, JY Dourmad and MC Père. 2009. Journal of Animal Science. 87: 532-543.