The impact of specialty protein ingredients on the growth performance and health of nursery pigs

Ruckman, Leigh
Major Professor
John F Patience
Committee Member
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Animal Science
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Animal Science

The pork industry is interested in feed additives, such as specialty protein ingredients, that can be fed to pigs in order to help mitigate the effects of weaning on pig performance and gastrointestinal tract (GIT) health and function. Functional specialty proteins, such as spray-dried plasma protein (SDPP) and hyperimmunized dried egg protein (DEP), have been identified as potential alternatives to dietary antibiotics due to their biologically active components (such as immunoglobulins) that can aid in pathogen inhibition in the GIT. However, the industry’s understanding of these protein’s mode of action and their impact in commercial environments is lacking. Reducing the inclusion of soybean meal (SBM), which contains anti-nutritional factors, in early nursery diets has been identified as a way to mitigate the effect of weaning stress in pigs. Enzymatically-treated SBM (ESBM) has reduced anti-nutritional factor concentrations and improved nutrient digestibility compared to SBM, but this ingredient has yielded inconsistent results in performance studies. Further, there is a lack of research investigating this ingredient’s mode of action, so its true value to producers is unknown. Therefore, the primary objective of the research reported in this thesis was to investigate the impact of specialty protein ingredients on nursery pig performance and specific markers of GIT health and function. In order to achieve these objectives, two experiments were conducted with the specific objectives to 1) compare under commercial conditions the effects of including SDPP or DEP in the diet, with or without subtherapeutic levels of antibiotics in the phase 1 and 2 nursery diets, on growth performance and markers of intestinal physiology and function (experiment 1), and 2) determine the impact of diets in which ESBM replaced increasing amounts of SBM on growth performance, intestinal structure and barrier integrity, inflammation, and oxidative status in newly weaned pigs (experiment 2). In experiment 1, (Chapter 2) the inclusion of either SDPP or DEP in the diet improved the growth rate and feed intake of weaned pigs when antibiotic-free diets were fed during phases 1 and 2. However, when antibiotic-positive diets were fed, the inclusion of SDPP or DEP failed to alter the growth performance of the pigs compared to that of the SBM control. Due to the low dietary inclusion of DEP versus SDPP (0.2% or 3% in phase 1; 0.1% or 2% in phase 2), feeding DEP was a cost-effective method to improve performance in the antibiotic-free diets. The pigs fed the SDPP and DEP required fewer individual medical treatments than pigs fed the control diet, indicating a positive effect on their overall health. Both SDPP and DEP were shown to beneficially modulate the inflammatory response in the GIT of pigs and slightly improve ileal morphology measures. Overall, this study provided novel data, collected under commercial conditions, about the impact of specialty proteins, in the absence or presence of antibiotics. In experiment 2 (Chapter 3), there was a linear decrease in final body weight and overall growth rate and feed intake of pigs due to feeding 14% or 21% ESBM (in phase 1; 7 or 10.5% in phase 2) compared to the control (0% ESBM) or the lowest ESBM diet (7 or 3.5% in phases 1 and 2). The inclusion of ESBM did not have any impact on feed efficiency. However, feeding ESBM, independent of inclusion level, improved the overall fecal score of pigs compared to the control, likely due to the reduction in the dietary concentration of the antigenic proteins glycinin and β-conglycinin and non-digestible oligosaccharides in ESBM. Further, feeding ESBM did beneficially modulate oxidative stress measures, improve intestinal barrier integrity markers, and increase volatile fatty acid production in the small intestine. Overall, this thesis research provided valuable and novel data to the swine industry regarding the use of specialty protein ingredients in nursery diets and how these proteins may impact pig performance and markers of GIT health and function. These data show that functional specialty proteins (such as SDPP and DEP) are beneficial in antibiotic-free feeding systems; however, a pork producer that is using in-feed antibiotics may not see the same improvements in pig performance when feeding these proteins. Further, increasing the inclusion of ESBM and decreasing SBM levels may benefit the GIT health of pigs, but performance will be impaired when feeding higher ESBM levels. In order to maximize the feeding value of specialty proteins, the industry needs further investigation into the dietary use of these proteins to fully understand their potential mode of action and impact on pig performance and health in commercial nursery environments.