Effects of a Dietary Select Essential Oil and Prebiotic Fiber Combination on Sow Reproductive and Litter Performance

Abstract Essential oils combined with functional prebiotics are increasingly utilized in swine nutrition for their potential to support immune function, gut health, and feed biosecurity, which may positively influence sow reproductive outcomes and litter performance. The objective of this study was to evaluate the impact of an in-feed select oregano essential oil (Microfused®) in combination with a proprietary prebiotic fiber (Actifibe®; Dual Defender™) on sow productivity and litter growth during lactation. This study was conducted on a commercial 10,000 sow breed-to-wean farm. A total of 507 sows were enrolled at breeding and randomly assigned to either a control group (CON; n = 232; basal gestation and lactation diets) or a treatment group (DD; n = 275; basal diets + 0.10% Dual Defender™). Diets were fed throughout gestation and lactation according to the farm’s standard feeding protocols. Sows with ≥9 piglets on d 1 of lactation were included in the lactation phase of the study and cross-fostering was allowed within treatment. Litter characteristics were recorded at birth and litter size and weight were recorded on d 1 of age and one day before weaning to evaluate litter growth performance. Sow productivity measures included total born, born alive, stillborn, mummies, number weaned, wean-to-estrus interval, and subsequent litter size. Data were analyzed using the PROC GLM procedure in SAS 9.4 and the model included treatment and parity with days of lactation (Avg=20.65d) as a covariate for weaning variables. Differences were considered significant at P ≤ 0.05 and trends at 0.05 P ≤ 0.10. On d 1, DD sows had heavier average piglet weight (1.46 vs. 1.41 kg; P = 0.025) compared to CON sows. There was a tendency for DD sows to have fewer light piglets ( 0.90 kg) per litter (0.83 vs. 1.02; P = 0.070) on d 1. Although number of total born (16.34, DD vs 16.03, CON; P = 0.292) and live-born piglets did not differ between treatments, DD sows had more stillborn piglets (0.90 vs. 0.59; P = 0.016). At weaning, DD sows had greater litter ADG (2.90 vs. 2.75 kg/d; P = 0.041) and adjusted 21-day litter weaning weight (80.94 vs. 77.61 kg; P = 0.033) as well as higher adjusted 21-day average piglet weaning weight (6.52 vs. 6.34 kg; P = 0.050). While number of piglets weaned did not differ between treatments (12.47, DD vs 12.35, CON; P = 0.531), there was a tendency for DD sows to have fewer light weight piglets ( 3.6 kg) at weaning (0.37 vs. 0.51; P = 0.082). Days to return to estrus were numerically shorter for the DD sows (4.59 vs 4.97; P = 0.1061). Subsequent litter size was not affected by treatment. Overall, Dual Defender™ supplementation during gestation and lactation improved piglet weights at birth and weaning and litter growth during lactation, with a tendency for fewer light weight piglets born and weaned.