| Popis: |
This thesis investigates the effect of feeding organic acids on performance and gut structure in the newly weaned pig. Pig performance and gut structure of pigs fed diets supplemented with a combination of 12g/kg (6.,50g/kg formic, 2.55g/kg propionic) acid and 500 FTU/kg phytase post-weaning was comparable with that of pigs fed diets medicated with 2.1 g/kg Zinc Oxide (ZnO). Formic/propionic acid blend and phytase were used in combination without any interactions and phytase can be used to replace dicalcium phosphate in weaner piglet diets. Litter of origin has a significant effect on small intestine structure and should be considered when investigating the effect of dietary treatment on gut development in the newly weaned pig. Supplementing diets with 1.5g/kg butyrate in its sodium salt form, but not in its esterified form, stimulated gut development; as indicated by longer villi in the proximal small intestine on day 13 post-weaning. Both sodium butyrate and esterified butyrate improved growth rates and FCR and were successfully used in combination with ZnO. Supplementing post-weaning diets with 3.1 g/kg ZnO was the most effective in stimulating feed intake, maintaining performance, enhancing gut development and reducing the incidence of scour in the newly weaned pig. Both indoor and outdoor reared pigs benefitted from ZnO supplementation in the first two weeks post-weaning. Outdoor reared pigs adapted better to the abrupt process of weaning, had a more developed distal small intestine post-weaning and outperformed their indoor reared counterparts due to their ability to maintain sufficient feed intakes. Feeding indoor reared pigs diets supplemented with esterified butyrate and/or ZnO post-weaning produced FCRssimilar to those of the outdoor reared pig, The positive effects on gut development and performance associated with ZnO highlights the value of medicating diets with pharmacological levels of ZnO in the critical period immediately following weaning. |
