Effects of Different Feeding Levels during Three Short Periods of Gestation on Gilt and Litter Performance, Nutrient Digestibility and Energy Homeostasis

The present study investigated the effects of different feeding levels during 3 short periods of gestation on gilt and litter performance, apparent total tract digestibility (ATTD) of energy and nutrients, and energy homeostasis. A total of 18 gilts were allotted to 1 of 3 dietary treatments using a completely randomized design. All gilts were fed one common corn-soybean meal-based diet with the amount being 1.0 × maintenance energy intake (100 × body weight (BW)^0.75 kcal ME/d) throughout gestation except 3 periods of 7 d when dietary treatments were imposed on d 27, 55 and 83 of gestation. During the 3 short periods, sows were fed 1 of 3 different feeding levels: 0.5, 1.0 and 2.0 × maintenance energy level (0.5M, 1.0M and 2.0M, respectively). Titanium dioxide at 0.3% inclusion rate in the diet was used as inert maker to measure the ATTD of energy and nutrients during the 3 short periods. GLIMMIX procedure was used to analyze all the data. Dietary treatment was considered as the fixed effect, while each animal was considered as the random effect. Results showed that gilts on 2.0M feeding level had higher (P < 0.05) BW gain from d 27 to 109 of gestation (37.05 vs. 15.34 kg). No differences (P > 0.10) for litter performance were observed among the 3 feeding levels in terms of number and weight of piglets born alive and at weaning. The slopes of BW change in response to feeding levels in period 1 were 4.32 kg/0.5M change from 0.5M to 1.0M feeding level and 3.72 kg/0.5M change from 1.0M to 2.0M feeding level, respectively. Additionally, there were quadratic (P < 0.05) effects of feeding levels on ATTD of dry matter (88.33, 89.03 and 85.90%; 86.16, 87.93 and 84.66%, respectively) and gross energy (88.03, 88.71 and 85.11%; 85.63, 87.57 and 83.69%, respectively) in periods 1 and 2 (d 55-62). Furthermore, fasting plasma concentrations of acyl ghrelin and non-esterified fatty acids (NEFA) in period 1 were greater (P < 0.01) in gilts on 0.5M feeding level than those on 2.0M feeding level. In conclusion, increasing feeding levels during 3 short periods of gestation increased primiparous sow BW gain during gestation but did not affect litter performance. ATTD of energy and nutrients, and BW change efficiency were maximized for gilts at 1.0 M feeding level. The data also indicated that sows on the lowest feeding level were exposed to negative energy balance.