An investigation into the potential of beta glucans and other bioactives to enhance gastrointestinal health, performance and product quality in pigs

The main research objective of this thesis was to investigate the potential of dietary supplements, namely casein hydrolysates and yeast ß glucan and mushroom powders, to enhance growth, gastrointestinal health and meat quality in weaned pigs and finisher pigs. Chapter 2 investigated the potential of maternal supplementation and/or post-weaning supplementation with a casein hydrolysate and yeast ß-glucan on the growth performance and gastrointestinal health of pigs, 10 days post-weaning. The combination of maternal and post weaning supplementation led to pigs having the lowest/healthiest faecal scores. Maternal supplementation led to pigs having an increase in feed efficiency and colonic butyrate concentrations while also increasing the pig’s relative abundance of colonic Lactobacillus and decreasing the relative abundance of colonic Enterobacteriaceae and Campylobacteraceae. Chapter 3 investigated the effects of mushroom powder and vitamin D2 enriched mushroom powder on the growth performance and health of newly weaned pigs. Supplementation of mushroom powder and vitamin D2 enriched mushroom powder to the diet of weaned pigs for the first 35 days post weaning resulted in similar average daily gain (ADG), gain-to-feed ratio (G:F), faecal scores and selected faecal microbial populations compared with the control diet. When compared with zinc oxide (ZnO), mushroom powder and vitamin D2 enriched mushroom powder supplementation reduced feed intake and increased faecal scores. Chapter 4 investigated the effects of varying levels of selenium (Se), in the form of Se enriched mushroom powder, on the growth performance and intestinal health of weaned pigs. Selenium enriched mushroom powder supplementation increased the relative abundance of caecal Prevotella, Lactobacillus and Faecalbacterium. Dietary supplementation with 0.3ppm Se led to similar faecal scores, ADG and G:F compared with the ZnO group up to day 21 post weaning while 0.6ppm Se supplementation during days 21 to 39 post weaning increased ADG and G:F and day 39 body weight compared with the basal group. Chapter 5 investigated the influence of duration of feeding vitamin D2 enriched mushroom powder to finisher pigs on growth performance and meat quality parameters. Vitamin D2 enriched mushroom powder supplementation, irrespective of feeding duration, improved feed efficiency, reduced feed intake and yielded higher overall pork FRAP values. Supplementation for 26 days prior to slaughter caused lipid oxidation to reduce and pork lightness (L*) to remain stable over a 21 day storage time-period. Overall, these studies demonstrate that maternal and post weaning supplementation with a casein hydrolysate and yeast ß glucan or post weaning supplementation with mushroom powder can enhance aspects of intestinal health and growth performance. The supplementation of vitamin D2 enriched mushroom powder also has the potential to enhance feed efficiency and pork quality in finisher pigs. However, further exploration is necessary to determine if these bioactive compounds and management strategies can replace zinc oxide and synthetic additives.