Feeding strategies for weaned pigs

Abstract

Weaning imposes a variety of stress factors on piglets including consuming dry feed instead of milk, changes of environment and physiology, and pathogenic challenges while decreasing passive immunity. Feeding strategies are cost-effectively attractive approaches to maintain health and promote growth in weaned pigs. While canola co-products are substitutes for soybean meal to reduce feed cost, fermented wheat holds significant potential to design a feeding strategy to promote growth and provide health benefits to weaned pigs. In Chapter 2, yellow-seeded Brassica (B.) juncea canola meal (CM) had greater fermentability and CATTD of gross energy than B. napus CM, but digestibility of amino acids did not differ, when fed to ileal-cannulated growing pigs. Fermentability of B. napus CM but not B. juncea CM decreased in the pig intestine with increased dietary inclusion up to 500 g/kg. Hence, yellow-seeded B. juncea CM had a greater DE value, similar amino acid digestibility as conventional black-seeded B. napus CM and may limit protein fermentation in the pig intestine. In Chapter 3, increasing inclusion of extruded B. juncea expeller at 0, 60, 120, 180 and 240 g/kg linearly decreased diet nutrient digestibility and energy values and quadratically increased overall ADFI and ADG, but did not affect overall G:F in weaned pigs. The linear increase of ADFI and ADG was curved at 240 g extruded B. juncea expeller/kg associated with increased dietary glucosinolates intake that prevented further increases in ADFI. In Chapter 4, six diets including 200 or 500 g/kg fermented wheat grain with Lactobacillus reuteri did not affect gut morphology, intestinal fermentation, growth performance, and CATTD of nutrients in weaned pigs. However, exopolysaccharides (EPS), reuteran or levan, demonstrated prebiotic effects by stimulating hindgut fermentation. Moreover, feeding fermented wheat with L. reuteri, especially with the presence of reuteran, reduced the copy numbers of genes for E. coli and its heat-stable enterotoxin in the intestinal digesta (Chapter 6). In conclusion, B. juncea CM had greater energy value and fermentability than conventional CM. Feeding fermented wheat with L. reuteri that produce exopolysaccharides may promote gut health benefits to weaned pigs.