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Impacts of dietary myristic acids on mucosa-associated microbiota in relation to intestinal health and growth parameters of nursery pigs

Hyunjun Choi, Gabriel Cipriano Rocha, 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 highly related to the growth of nursery pigs (Moeser et al., 2017).
  • Newly weaned pigs are exposed to environmental, immunological, psychological, and nutritional challenges.
    • Altered jejunal mucosa-associated microbiota (Duarte and Kim, 2022)
    • Increased inflammatory responses and oxidative stress in the jejunum (Kim and Duarte, 2021)
    • Decreased intestinal morphology (Pluske et al., 2016)
    • Reduced nutrient utilization and growth performance (Moeser et al., 2017)

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DEPARTMENT OF ANIMAL SCIENCE

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AGP ban and alternative: myristic acid

  • Since the ban of AGP, the investigation of AGP alternatives has been demanded to improve intestinal health and growth of young pigs.
  • Myristic acid
    • Saturated fatty acids with 14 carbon atoms
    • High antimicrobial properties (Debois and Smith, 2010)
    • Attach to the cell wall of opportunistic pathogenic bacteria, which change
      • Bacterial cell membrane permeability, showing antimicrobial activity (Chen et al., 2019; Liu and Huang, 2012)
    • Would have antimicrobial effects on the jejunal mucosa-associated microbiota, which reduce pathogenic bacteria and promote intestinal health of pigs (Kim and Duarte, 2021; Duarte and Kim, 2022)

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Hypothesis and objective

  • It was hypothesized that dietary myristic acid as an AGP alternative can enhance intestinal health and growth of nursery pigs by modulating mucosa-associated microbiota and mucosal immune status in the jejunum.
  • The objective of this study was to evaluate the role of dietary myristic acid on mucosa-associated microbiota and mucosal immune responses in the jejunum in relation to the growth performance of nursery pigs

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: animals, design, and diets

  • A total of 36 pigs (18 barrows and 18 gilts; 6.6 ± 0.4 kg BW)
    • Individually housed in a pen (n = 12 per treatment)
  • Randomized complete block design with initial BW and sex as blocks
  • Dietary treatments:
    • Negative control (NC): basal diet
    • Positive control (PC): NC + 0.25% BMD50 (bacitracin: 0.03% feed)
    • Myristic acid (MA): NC + MA compound at 0.20% in P1 and 2; 0.12% in P3
  • Experimental diets fed in 3 phases for 35 d (10, 10, and 15 d).

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Materials and methods

Item

P 1

P 2

P 3

Corn

31.54

45.80

67.95

Soybean meal

19.00

23.00

26.00

Whey permeate

20.00

14.00

-

Poultry meal

7.00

3.00

-

Cookie meal

10.00

5.00

-

Fish meal

4.00

2.00

-

Blood plasma

2.00

2.00

2.00

Others

6.56

6.99

6.03

Item

P 1

P 2

P 3

DM, %

91.02

90.32

89.38

ME, kcal/kg

3,484

3,425

3,388

CP, %

24.18

21.20

18.90

SID Lys, %

1.51

1.36

1.24

SID Met + Cys, %

0.84

0.75

0.69

SID Thr, %

0.88

0.80

0.74

SID Trp, %

0.26

0.24

0.21

Total Ca, %

0.86

0.80

0.72

STTD P, %

0.46

0.41

0.34

Table 1. Composition of basal diets

Table 2. calculated feed composition

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Materials and methods: data and sample collection

  • Growth performance
    • ADG, ADFI, and G:F
  • Jejunal mucosa and jejunal tissues for intestinal health
    • Microbial diversity and relative abundance (RA) of mucosa-associated microbiota
    • IgA, IgG, IL-8, and TNF-α (immune status)
    • Protein carbonyl and malondialdehyde (oxidative damage products)
    • Villus height, crypt depth, and villus height to crypt depth ratio (VH:CD; intestinal morphology)
    • Immunohistochemistry of Ki-67+ (crypt cell proliferation)

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: statistical analysis

  • Randomized complete block design
    • Experimental unit: pen
    • Fixed effect: dietary treatment
    • Random effects: initial BW block (heavy and light) and sex block
  • Preplanned contrasts in the Proc Mixed procedure of SAS 9.4
    • NC vs. PC and NC vs. MA
  • CORR procedure to test the correlation among variables
  • Significance: P < 0.05; tendency: 0.05 ≤ P < 0.10

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DEPARTMENT OF ANIMAL SCIENCE

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Results: alpha diversity of jejunal mucosa-associated microbiota

NC vs PC: 0.777

NC vs MA: < 0.05

NC vs PC: 0.100

NC vs MA: < 0.05

NC vs PC: < 0.05

NC vs MA: < 0.05

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Results: RA of jejunal mucosa-associated microbiota (family)

NC vs PC: < 0.05

NC vs MA: 0.266

NC vs PC: 0.137

NC vs MA: 0.072

NC vs PC: 0.075

NC vs MA: < 0.05

NC vs PC: 0.633

NC vs MA: < 0.05

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Results: RA of jejunal mucosa-associated microbiota (species)

NC vs PC: < 0.05

NC vs MA: 0.909

NC vs PC: < 0.05

NC vs MA: 0.947

NC vs PC: 0.710

NC vs MA: < 0.05

NC vs PC: 0.190

NC vs MA: < 0.05

NC vs PC: < 0.05

NC vs MA: 0.198

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Results: immune status (jejunal mucosa)

NC vs PC: 0.923

NC vs MA: 0.769

NC vs PC: 0.192

NC vs MA: 0.051

NC vs PC: 0.284

NC vs MA: 0.200

NC vs PC: 0.053

NC vs MA: 0.090

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DEPARTMENT OF ANIMAL SCIENCE

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Results: pearson correlation (r)

IgG

(P < 0.05)

Bifidobacteriaceae (-0.58)

Veillonellaceae (-0.49)

Bifidobacterium boum (-0.43)

Megasphaera sp (-0.61)

IL-8

Lactobacillaceae (-0.59)

Bifidobacteriaceae (-0.58)

Bifidobacterium boum (-0.53)

TNF-α

Bifidobacteriaceae (-0.46)

Ruminococcaceae (0.71)

Bifidobacterium boum (-0.41)

IgA

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Results: oxidative damage products (jejunal mucosa)

NC vs PC: 0.349

NC vs MA: 0.234

NC vs PC: 0.075

NC vs MA: 0.323

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Results: pearson correlation (r)

Protein Carbonyl

(P < 0.05)

Lactobacillaceae (-0.54)

Bifidobacteriaceae (-0.64)

MDA

Lactobacillaceae (0.44)

Bifidobacterium boum (-0.66)

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Results: intestinal morphology (jejunum)

NC vs PC: 0.115

NC vs MA: 0.489

NC vs PC: 0.681

NC vs MA: 0.732

NC vs PC: < 0.05

NC vs MA: 0.642

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Results: pearson correlation (r)

VH

(P < 0.05)

Bifidobacterium boum (0.58)

VH:CD

CD

Ki-67+

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Results: growth performance

NC vs PC: 0.063

NC vs MA: < 0.05

NC vs PC: 0.051

NC vs MA: < 0.05

NC vs PC: 0.411

NC vs MA: 0.396

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DEPARTMENT OF ANIMAL SCIENCE

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Results: pearson correlation (r)

ADFI

(P < 0.05)

Lactobacillaceae (0.43)

Bifidobacteriaceae (0.49)

Lactobacillus sp (0.44)

ADG

Bifidobacteriaceae (0.51)

G:F

Lactobacillaceae (-0.42)

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DEPARTMENT OF ANIMAL SCIENCE

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Summary and conclusion

  • Myristic acid as an AGP alternative showed similar beneficial effects with bacitracin on intestinal health and growth of pigs.
  • Myristic acid, however, mainly increased relative abundance (RA) of Bifidobacterium and Megasphaera, whereas bacitracin increased RA of Lactobacillus and Mitsuokella in the jejunal mucosa.
  • The positive modulations of RA of mucosa-associated microbiota by bacitracin and myristic acid were strongly correlated with improved intestinal health and growth of nursery pigs.

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DEPARTMENT OF ANIMAL SCIENCE

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Thank you!� Thoughts? Questions?

Acknowledgments:

NC STATE UNIVERSITY

DEPARTMENT OF ANIMAL SCIENCE