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Impacts of increasing soybean meal on jejunal immunity of �nursery pigs at different ages post-weaning

Hyunjun Choi, Zixiao Deng, and Sung Woo Kim

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North Carolina State University, Raleigh, NC

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NC STATE UNIVERSITY

DEPARTMENT OF ANIMAL SCIENCE

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Post-weaning period

  • Weaning is the most critical event for intestinal health, which is closely related to the growth of nursery pigs.
  • Nursery pigs are exposed to environmental, immunological, psychological, and nutritional challenges, leading to:
    • ↓ Jejunal mucosa-associated microbiota
    • ↑ Jejunal inflammatory responses
    • ↑ Jejunal oxidative damage products
    • ↓ Intestinal morphology
    • ↓ Nutrient utilization and growth performance

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(Moeser et al., 2017; Pluske et al., 2016; Kim and Duarte, 2021; Duarte and Kim, 2022)

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DEPARTMENT OF ANIMAL SCIENCE

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Soybean meal (SBM) in nursery diets

  • Diets for nursery pigs often include expensive, highly digestible feedstuffs to help pigs adapt to solid feeds.
  • In contrast, SBM is commonly used as a cost-effective protein supplement.
    • However, SBM contains anti-nutritional compounds, such as allergenic proteins, phytate, and non-starch polysaccharides, which can negatively affect the intestinal health and growth of nursery pigs.
  • Based on previous findings, the negative impacts of SBM would be more pronounced in pigs at 20 d post-weaning than in pigs at 42 d post-weaning.
    • 20 d post-weaning = end of phase 2; 42 d post weaning = end of phase 3

(Skinner et al., 2014; Hansen et al., 1993; Hong et al., 2004; Deng and Kim, 2024)

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DEPARTMENT OF ANIMAL SCIENCE

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Hypothesis and objective

  • Hypothesis
    • Nursery pigs would experience greater jejunal immune compromise due to anti-nutritional compounds in SBM at 20 d post-weaning compared to pigs 42 d post-weaning.
  • Objective
    • To investigate the impacts of increasing SBM levels in feed on jejunal mucosal microbiota and jejunal immunity in nursery pigs at different ages post-weaning.

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: animals, design, and feeds

  • A total of 48 pigs (24 barrows and 24 gilts; 6.2 ± 0.3 kg BW)
    • Individually housed in a pen (n = 12 per treatment).
  • Randomized complete block design, with initial BW and sex as blocks
  • Treatments included low and high SBM levels in diets.
  • d 20 and 42 post-weaning (At 41 d and 63 d of age), pigs were euthanized.
  • Treatment arrangements:
    • 2 × 2 factors with SBM levels (low and high) and age (d 20 and 42 post-weaning)
  • Experimental feeds were fed in 3 phases for 42 d (P1: to 7 kg, P2: 7 to 11 kg, and P3: 11 kg to end).

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: composition of experimental diets

 

Phase 1

 

Phase 2

 

Phase 3

Item

Low SBM

High SBM

 

Low SBM

High SBM

 

Low SBM

High SBM

Feedstuff, %

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​

​

​

​

​

​

​

Corn, yellow dent

44.24

39.21

​

56.33

51.24

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70.13

62.59

Soybean meal (SBM)

16.00

30.00

​

17.00

31.00

​

20.50

34.50

Enzyme-treated SBM

6.00

-

​

6.00

-

​

6.00

-

Fish meal

4.00

3.00

​

2.00

2.00

​

-

-

Poultry meal

3.00

2.00

​

2.00

-

​

-

-

Blood plasma

4.00

3.00

​

1.50

-

​

-

-

Poultry fat

-

-

​

-

0.55

​

-

-

Whey permeate

20.00

20.00

​

12.00

12.00

​

-

-

Others

2.76

2.79

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3.17

3.21

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3.37

2.91

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: data and sample collection

  • BW and feed intake were measured at the end of each phase.
  • Pigs were euthanized to collect samples on d 20 and 42 post-weaning.
    • Jejunal mucosa and jejunal tissues for intestinal health
      • Alpha diversity and relative abundance (RA) of mucosa-associated microbiota
      • IgA, IgG, IL-6, IL-8, and TNF-α: immune response
      • Protein carbonyl and malondialdehyde: oxidative damage products
      • Villus height, crypt depth, and VH:CD: intestinal morphology
      • Ki-67+ cell: crypt cell proliferation

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: statistical analysis

  • Randomized complete block design
    • Fixed effects: SBM level (low and high), age (d 20 and d 42 post-weaning), and the interaction between SBM level and age
    • Random effects: initial BW and sex
    • Experimental unit: a pig
  • Significance: P < 0.05; tendency: 0.05 ≤ P < 0.10

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DEPARTMENT OF ANIMAL SCIENCE

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Alpha diversity in the jejunal mucosal microbiota

Low High

Age:

SBM:

P value:

SBM: 0.430;

Age: <0.05;

SBM×Age: 0.258

P value:

SBM: 0.647;

Age: <0.05;

SBM×Age: 0.287

P value:

SBM: 0.700;

Age: <0.05;

SBM×Age: 0.200

Low High

Low High

Age:

SBM:

Age:

SBM:

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Relative abundance of jejunal mucosal microbiota

P value:

SBM: 0.757;

Age: <0.05;

SBM×Age: 0.610

P value:

SBM: 0.257;

Age: <0.05;

SBM×Age: 0.678

P value:

SBM: <0.05;

Age: 0.911;

SBM×Age: 0.502

Age:

SBM:

Age:

SBM:

Age:

SBM:

Low High

Low High

Low High

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Jejunal immune responses

P value:

SBM: 0.091;

Age: 0.059;

SBM×Age: 0.226

P value:

SBM: 0.567;

Age: 0.090;

SBM×Age: 0.380

Age:

SBM:

Age:

SBM:

Low High

Low High

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DEPARTMENT OF ANIMAL SCIENCE

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Jejunal immune responses

P value:

SBM: 0.473;

Age: <0.05;

SBM×Age: 0.173

P value:

SBM: 0.260;

Age: 0.747;

SBM×Age: 0.845

P value:

SBM: 0.186;

Age: 0.177;

SBM×Age: 0.117

Low High

Low High

Low High

Age:

SBM:

Age:

SBM:

Age:

SBM:

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Jejunal oxidative damage products

P value:

SBM: 0.609;

Age: <0.05;

SBM×Age: 0.590

P value:

SBM: 0.217;

Age: 0.427;

SBM×Age: 0.249

Low High

Age:

SBM:

Low High

Age:

SBM:

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Jejunal morphology and cell proliferation

P value:

SBM: 0.971;

Age: 0.471;

SBM×Age: 0.535

P value:

SBM: <0.05;

Age: 0.123;

SBM×Age: 0.523

Low High

Age:

SBM:

Low High

Age:

SBM:

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Jejunal morphology and cell proliferation

P value:

SBM: 0.056;

Age: 0.608;

SBM×Age: 0.982

P value:

SBM: 0.668;

Age: <0.05;

SBM×Age: 0.846

Age:

SBM:

Low High

Low High

Age:

SBM:

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DEPARTMENT OF ANIMAL SCIENCE

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Summary

  • High SBM in diets showed negative impacts on jejunal immunity.
    • ↑ RA of Prevotella
    • ↑ Jejunal IgA
    • ↑ Crypt depth
    • ↓ VH:CD
  • Pigs at 20 d post-weaning showed compromised jejunal immunity.
    • ↓ Microbial diversity in the Chao 1, Shannon, and Simpson indices
    • ↑ RA of Lactobacilus and ↓ RA of Bifidobacterium
    • ↑ Jejunal IgG and IL-8
    • ↑ Jejunal protein carbonyl
    • ↑ Crypt cell proliferation

​

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DEPARTMENT OF ANIMAL SCIENCE

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Conclusion

  • Nursery pigs fed high SBM diets exhibited a greater immune response and reduced intestinal morphology in the jejunum compared to those fed low SBM diets.
  • Nursery pigs at 20 d post-weaning were more vulnerable to compromised jejunal immunity compared to pigs at 42 d post-weaning, showing an increased immune response and oxidative damage, and impaired intestinal morphology.
  • Nursery pigs at 20 d post-weaning were more vulnerable to compromised jejunal immunity compared to at 42 d post-weaning, but high SBM feeds did not cause greater damage at 20 d post-weaning compared to 42 d post-weaning.

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DEPARTMENT OF ANIMAL SCIENCE

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Thank you!� Thoughts? Questions?

Kim Lab 2024

Acknowledgments:

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DEPARTMENT OF ANIMAL SCIENCE

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Growth performance (phases 1 and 2)

Low High

Age:

SBM:

P value:

SBM: 0.301;

Age: 0.996;

SBM×Age: 0.842

P value:

SBM: 0.055;

Age: 0.940;

SBM×Age: 0.884

P value:

SBM: 0.074;

Age: 0.683;

SBM×Age: 0.529

Low High

Low High

Age:

SBM:

Age:

SBM:

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DEPARTMENT OF ANIMAL SCIENCE

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Growth performance (phase 1)

Low High

Age:

SBM:

P value:

SBM: <0.05;

Age: 0.933;

SBM×Age: 0.501

P value:

SBM: <0.05;

Age: 0.939;

SBM×Age: 0.500

P value:

SBM: <0.05;

Age: 0.939;

SBM×Age: 0.500

Low High

Low High

Age:

SBM:

Age:

SBM:

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DEPARTMENT OF ANIMAL SCIENCE

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Growth performance (phase 2)

Low High

Age:

SBM:

P value:

SBM: 0.685;

Age: 0.934;

SBM×Age: 0.460

P value:

SBM: 0.160;

Age: 0.894;

SBM×Age: 0.630

P value:

SBM: <0.05;

Age: 0.683;

SBM×Age: 0.206

Low High

Low High

Age:

SBM:

Age:

SBM:

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DEPARTMENT OF ANIMAL SCIENCE