490 Lifetime growth performance and carcass composition of offspring when inactivated Saccharomyces cerevisiae was included in gestating and lactating gilt diets and/or offspring nursery diets
Authors: Christensen Brenda , Schulze Hagen , Kiarie Elijah , Huber Lee-Anne 
Published: September 2024

Abstract
Gilts [n = 90; initial body weight (BW) = 189.1 ± 3.9 kg] were used to determine the effect of feeding a yeast additive (Saccharomyces cerevisiae inactivated through hydrolyzation; HY) to gestating and lactating gilts and/or the offspring during the nursery period on lifetime offspring growth performance. Gilts were randomly assigned to one of three dietary treatments (n = 30/treatment): standard gestation and lactation diets (GHY0) or supplemented with 0.25% (GHY0.25) or 1% (GHY1.0) HY. Diets were fed between d 85 of gestation until weaning at d 21 (2.6 kg/d in gestation, ad libitum in lactation). At weaning, 8 piglets/litter were placed in nursery pens and pens were randomly assigned to a control (NO) or a HY-supplemented diet (NHY), apart from GHY1.0 offspring who were only provided NO during the nursery period (n = 12). In nursery phases 1, 2 and 3, HY was included at 0.75, 0.50, and 0.25% respectively. Thereafter, pigs received standard grower and finisher rations until slaughter (160 d of age). Data were analyzed in SAS using GLIMMIX with gilt treatment as the main effect (pre-weaning); post-weaning performance used gilt and nursery treatments as the main effects, and interactive effects were tested separately due to the incomplete 3 × 2 factorial design. Mean comparisons were conducted using the Tukey-Kramer test to separate LSmeans. Gilt BW was unaffected by gilt treatment, but gilts fed GHY1.0 had greater total lactation feed intake versus GHY0.25 (128.6 vs. 109.4 ± 7.7 kg; P &lt; 0.01). At birth, GHY0.25 offspring were 70 g heavier than pigs from GHY0 (P &lt; 0.001) with GHY1.0 intermediate. At weaning, GHY0.25 and GHY1.0 offspring were heavier than GHY0 offspring (5.9 vs. 5.6 kg; P &lt; 0.001). After weaning, neither gilt nor nursery diet influenced offspring BW. Pigs fed GHY1.0-NO had greater ADFI versus all other treatments in the nursery (interaction; P &lt; 0.001), GHY0.25-NHY had greater ADFI than GHY0.25-NO and GHY1.0-NO in the grower (interaction; P = 0.005), and NHY consumed more feed than NO in the finisher phase (main effect; P &lt; 0.001). In the nursery, NHY had less average daily feed intake (ADFI) than NO (main effect; P &lt; 0.05), but in grower and finisher, NHY had greater ADFI than NO pigs (main effect; P &lt; 0.001). In the nursery, gain to feed (G:F) was greater for GHY0-NHY versus GHY0.25-NHY and GHY1.0-NO, and greater for GHY0-NO versus GHY0.25-NHY with all other treatments intermediate (interaction; P &lt; 0.05). In the grower phase, G:F was unaffected by maternal or nursery diet, but in the finisher phase, G:F was less for pigs fed NHY versus NO during the nursery phase (main effect; P &lt; 0.05). Slaughter BW, hot carcass weight, and fat and lean percents were not influenced by gilt or nursery diet. Therefore, HY provided to gilts during gestation and lactation, improved pre-weaning offspring growth, but HY supplemented to pigs during the nursery period had greater positive effects on lifetime growth performance.