Document Type

Thesis - Open Access

Award Date

2017

Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Crystal L. Levesque

Keywords

alternative, amino acids amino acids, bioprocessed soybean meal, immune response, nursery pig, weaning

Abstract

Weaning is a stressful time in a piglet’s life that can have negative impacts on performance and health if not managed properly. The objective of this research was to evaluate the effects of a bioprocessed SBM alone or in combination with spray-dried plasma (SDP) or fishmeal (FM) on immune response at weaning with no imminent disease threat and during a porcine reproductive and respiratory virus (PRRSV) challenge. In the first trial, 239 pigs (initial BW 6.56 ± 0.87 kg, 21 d of age) were used in a 35-d study and allotted to one of 4 dietary treatments (10 pens/trt) according to initial BW and sex: positive control (CON; corn/SBM diet) containing SDP and FM, the CON with bioprocessed SBM replacing FM (BPSBM+SDP), the CON with bioprocessed SBM replacing SDP (BPSBM+FM), and the CON with bioprocessed SBM replacing SDP and FM (BPSBM). Experimental diets were fed in Phase I (d 1-7 after weaning) and II (d 8- 21) followed by a common Phase III diet (d 22-35). Assessment of immune response was based on mitogenic lymphocyte proliferation and dermal hypersensitivity and anti- IgG assay to previously sensitized antigens. Pigs fed CON were heavier (P < 0.01) than pigs fed BPSBM+FM and BPSBM, and not different from pigs fed BPSBM+SDP, at the end of Phase I and II (6.99, 6.80, 6.52, or 6.60 kg, pooled SEM 0.08, respectively in Phase I or 12.47, 12.18, 11.42, and 11.85 kg, pooled SEM 0.21, in Phase II, respectively). There was no difference in lymphocyte proliferation or dermal hypersensitivity due to experimental diet. Secondary anti-OVA IgG was 2-fold lower based on optical density values in pigs fed CON compared with BPSBM+FM and BPSBM (0.78 vs. 1.56 and 1.55, pooled SEM 0.42 OD405nm, respectively). In the second trial, a total of 72 barrows (initial BW 6.68 ± 0.15 kg, 21 d of age) were used in a 21-d study (-7 to 14 d post-inoculation, DPI) with 48 PRRSV infected (POS) and 24 uninfected (SHAM) pigs. All pigs were housed individually (12 pigs/room) with POS and SHAM pigs in separate buildings and no staff transfer between buildings. POS pigs were allotted to one of the 4 diets from the first trial and SHAM pigs were allotted to either the CON or BPSBM diets. Experimental diets were fed in Phase I (-7 to 0 DPI) and II (1 to 14 DPI). On -7 DPI, SHAM pigs were vaccinated with a commercial porcine circovirus (PCV2) vaccine for determination of PCV2 neutralizing antibodies. On 0 DPI, POS pigs received a 1 x 105 tissue culture infective dose of PRRSV (NADC20) diluted in 1 mL of cell culture media. Body weight and rectal temperature were measured, and a blood sample collected on 0, 3, 7, 10, and 14 DPI. At 14 DPI, all pigs were euthanized and the lungs were removed for gross and microscopic lesion scoring. SHAM pigs had negative serum virus titers at all timepoints while POS pigs had positive serum virus titers at 3, 7, 10, and 14 DPI. POS pigs had higher rectal temperatures at 3 DPI (39.5 vs. 38.9, pooled SEM 0.09 °C, P < 0.001). Dietary treatment did not impact growth performance or serum virus load at any time point. In SHAM pigs, pigs fed BPSBM had a greater proportion of pigs (P < 0.05) with high levels of circulating PCV2 neutralizing antibodies compared to CON-fed pigs. The similar growth performance in pigs from both trials indicates that bioprocessed SBM can successfully replace SDP or FM and the positive impact of bioprocessed SBM on adaptive immune response indicates potential improved disease protection within commercial vaccination programs.

Library of Congress Subject Headings

Piglets -- Feeding and feeds.
Piglets -- Disease resistance.
Swine -- Feeding and feeds.
Soybean meal as feed.
Immunity -- Nutritional aspects.
Immune response.

Description

Includes bibliographical references (pages 73-84)

Format

application/pdf

Number of Pages

97

Publisher

South Dakota State University

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Rights Statement

In Copyright