Diet Complexity Affects Post-weaning Performance and Immune Response to Porcine Circovirus 2 (PCV2) Infection in Nursery Pigs

Abstract Text: To investigate the effects of complex and prebiotic diets on nursery pigs inoculated for or vaccinated against PCV2 on growth performance and immune parameters, 96 weaned barrows (age 27 to 40 d; BW 7.1 kg) were housed (4 pigs/pen) in an environmentally-controlled nursery with ad libitum access to feed and water over a 28-d study. Forty-eight pigs were vaccinated (VAC) for PCV2 prior to arrival, while remaining pigs (PCV) were inoculated for PCV2 on d 0. Pigs were randomly assigned to 1 of 3 diets: complex (CO; lactose, spray-dried plasma, spray-dried whey), simple (SI; corn and SBM), or simple + 2.5% Grobiotic-S (GS). Blood samples were obtained twice per week (d -2 to 28) for serum cytokine and PCV2-specific immunoglobulin (Ig) G and M quantification. No significant time, diet, or PCV-status interactions were observed for growth performance. Body weight tended (P < 0.06; d 14 to 28) to be greater in VAC (11.1 to 18.4 kg) compared to PCV (10.3 to 16.7 kg) pigs, and overall ADG (P < 0. 04) and ADFI (P < 0.03) were greater in VAC (0.40 kg and 0.68 kg, respectively) compared to PCV (0.35 kg and 0.61kg, respectively) pigs. Overall, pigs fed CO (0.71 kg) had greater (P < 0.02) ADFI compared to GS (0.61 kg) pigs and tended (P < 0.08) to be greater than SI (0.63 kg) pigs. Pigs fed CO (0.60) had greater (P < 0.05) G:F (d 0 to 7) compared to GS (0.46) and SI (0.51); however, G:F (P < 0.05; d 21 to 28) was decreased in CO (0.59) pigs compared to SI (0.67) pigs. For IgG, a diet x PCV-status interaction was observed (P < 0.04); PCV pigs fed SI and GS had increased PCV2-specific IgG (P < 0.05) compared to CO pigs. No effects of PCV-status or diet were observed with respect to IL-12p40, IL-6, IL-8, IL-10, or TNF-α; however, main effects of PCV-status (IFN-α; P < 0.01) and diet (IL-1β; P < 0.03) were observed. Specifically, greater IFN-α was observed for PCV compared to VAC pigs on d 11 (P < 0.02) and 14 (P < 0.02), and pigs fed CO had greater overall IL-1β compared to GS (P < 0.04) and SI (P < 0.02). Results indicate a complex nursery diet may improve post-weaning growth performance and affect immune response to PCV2 infection.

Keywords: health, pig, PCV2