Evaluation of oregano (Origanum vulgare) essential oils in swine production system

The general objective of this thesis was to provide a scientific basis for the use of oregano essential oils (OEO) in swine production systems. One hundred fifty sows were fed a control (Corn-SBM) or oregano (Regano500 RTM) diet during gestation and/or lactation. Sows supplemented with OEO during gestation farrowed on average 1.1 more piglets per litter. Breeding value sow productivity and sow productivity indices were higher in OEO-fed sows (104 vs. 99 and 115 vs. 98, respectively). Colostrum from OEO-fed sows contained 26% more IGF-1 and 50% more T-lymphocytes. Piglets from OEO-fed sows had a significantly higher percentage of gammadelta and NK activity before suckling than controls (+6% and +2.2%, respectively). Growth rate (g/day) of piglets between 16-19 days of age increased 9.7% relative to controls. The COUNT growth model demonstrated a difference between OEO and control sow lactation diets on velocity of growth (+10%).; Three hundred eighty-four weaned pigs from sows fed control or oregano diets were randomly assigned to one of four treatments: control, antibiotic, oregano and oregano+antibiotic. OEO supplementation may have physiological properties that improved intestinal mucosal area of pigs. Nursery growth rate (g/day) of pigs from OEO-fed sows increased 9% and villus to crypt ratio (VCR) of pigs increased by 8.5% compared to control, and VCR in pigs fed OEO increased 42.5% relative to control. Pigs supplemented with OEO increased the metabolizability of the diet by 4% compared to control. Pigs from OEO-fed grew faster (28 g/d) and ate more feed (65 g/d) than pigs from sows without supplementation during the wean-to-finish period. OEO supplementation in pig diets showed overall average daily gain increase of 20 g/d. Pigs from OEO-fed sows had increased loin depth (0.10 mm), percent lean (0.4%) and carcass value ({dollar}4.90) compared to controls.; Dietary supplementation of OEO adjusted nutrient partitioning in sows to essential functions enhancing reproductive efficiency with economical implications. Sows fed OEO earned on average {dollar}57.30 more per litter than sows with no supplementation. Furthermore, finished pigs from sows fed OEO earned {dollar}3.20 more than control.