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Effects of myristic acid as an antibiotic alternative on jejunal mucosa-associated microbiota, intestinal health, and growth performance 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.
  • Newly weaned pigs are exposed to environmental, immunological, psychological, and nutritional challenges.
    • Changed microbiota in intestine of pigs
    • Increased pro-inflammatory cytokines of intestine
    • Compromised morphology of intestine
    • Reduced growth performance

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(Pluske, 2016; Moeser et al., 2017)

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DEPARTMENT OF ANIMAL SCIENCE

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Current concerns with use of antibiotics

  • Antibiotics have been supplemented to swine feeds.
  • Bacitracin methylene disalicylate (BMD) have been used for growth promoters in animal feeds.
  • Use of antibiotics have been phased out due to:
    • Antibiotic residues in animal products
    • Antibiotic-resistant bacteria
  • The investigation of antibiotic alternatives has been demanded to improve the intestinal health and growth performance of pigs.

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(Casewell et al., 2003; De Lange et al., 2010)

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DEPARTMENT OF ANIMAL SCIENCE

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Antibiotic alternative: myristic acid

  • Myristic acid (MA)
    • Saturated fatty acid with 14 number carbon atoms
    • High antimicrobial properties
    • Attach to cell membrane of bacteria, which disrupt the electron transport chain, oxidative phosphorylation, and cellular energy production
    • Would expect to have antibacterial properties in the digesta of pigs, which reduce opportunistic pathogenic bacteria and promote intestinal health of pigs

(Debois and Smith, 2010; Liu, 2015)

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DEPARTMENT OF ANIMAL SCIENCE

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Hypothesis

  • It is hypothesized that myristic acid as an antibiotic alternative would show antimicrobial properties in the small intestine of nursery pigs by positively modulating mucosa-associated microbiota and improving intestinal health and growth performance of nursery pigs.

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DEPARTMENT OF ANIMAL SCIENCE

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Objective

  • To investigate the effects of dietary myristic acid as an antibiotic alternative on jejunal mucosa-associated microbiota, intestinal health, and 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; n = 12/trt)
  • 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: 276 mg/kg)
    • Myristic acid (MA): NC + MA at 0.08% in P1 and 2; 0.05% in P3
  • Myristic acid (Insighter Biotechnology, Guangzhou, China)
  • Experimental diets fed in 3 phases for 35 d (10, 10, and 15 d).
  • Titanium dioxide was supplemented to the diets from d 28 to 35.

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: composition of basal diets

1 Others included poultry fat, L-Lys HCI, DL-Met, L-Trp, L-Val, dicalcium phosphate, limestone, sodium chloride, vitamin premix, and mineral premix.

Item

Phase 1

Phase 2

Phase 3

Feedstuff, %

 

 

 

Corn, yellow dent

31.54

45.80

67.95

Soybean meal, 48% CP

19.00

23.00

26.00

Whey permeate, 80% lactose

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

Others1

6.06

6.49

5.53

Supplement (corn and feed additives)

0.50

0.50

0.50

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DEPARTMENT OF ANIMAL SCIENCE

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Materials and methods: calculated composition of basal diets

1 SID = standardized ileal digestible

2 STTD = standardized total tract digestible

Item

Phase 1

Phase 2

Phase 3

Dry matter, %

91.02

90.32

89.38

Metabolizable energy, kcal/kg

3,484

3,425

3,388

Crude protein, %

24.18

21.20

18.90

SID1 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

STTD2 P, %

0.46

0.41

0.34

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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 on d 0, 10, 20, and 35.
  • Fecal score was measured during all the experimental period (3-d interval).
  • All pigs were euthanized to collect samples on d 35.
    • Jejunal mucosa and jejunal tissues for intestinal health
      • Relative abundance of mucosa-associated microbiota
      • IgA, IgG, IL-8, TNF-α, protein carbonyl, and malondialdehyde (MDA)
      • Morphology and crypt cell proliferation
    • Ileal digesta for apparent ileal digestibility of nutrients
      • Dry matter, gross energy, crude protein, and ether extract

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Materials and methods: statistical analysis

  • Randomized complete block design
    • Experimental unit: pen
    • Fixed effect: dietary treatment
    • Random effects: initial BW and sex
  • Preplanned contrast in Proc MIXED procedure of SAS 9.4
    • NC vs. PC and NC vs. MA
  • Significance: P < 0.05; tendency: 0.05 ≤ P < 0.10

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DEPARTMENT OF ANIMAL SCIENCE

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Results: average daily gain (ADG)

NC vs PC: < 0.05

NC vs MA: 0.327

NC vs PC: 0.055

NC vs MA: 0.196

NC vs PC: 0.063

NC vs MA: < 0.05

NC vs PC: 0.240

NC vs MA: < 0.05

P value

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DEPARTMENT OF ANIMAL SCIENCE

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Results: average daily feed intake (ADFI)

NC vs PC: < 0.05

NC vs MA: 0.445

NC vs PC: 0.055

NC vs MA: 0.111

NC vs PC: 0.051

NC vs MA: < 0.05

NC vs PC: 0.152

NC vs MA: < 0.05

P value

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DEPARTMENT OF ANIMAL SCIENCE

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Results: gain to feed ratio (G:F)

NC vs PC: < 0.05

NC vs MA: 0.146

NC vs PC: 0.833

NC vs MA: 0.675

NC vs PC: 0.411

NC vs MA: 0.396

NC vs PC: 0.886

NC vs MA: 0.547

P value

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Results: fecal score

NC vs PC: 0.857

NC vs MA: 0.686

NC vs PC: < 0.05

NC vs MA: 0.129

NC vs PC: 0.198

NC vs MA: 0.311

NC vs PC: 0.348

NC vs MA: 0.348

P value

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DEPARTMENT OF ANIMAL SCIENCE

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Results: immune status

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

P value

NC vs PC: 0.053

NC vs MA: 0.090

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Results: oxidative damaged product

NC vs PC: 0.349

NC vs MA: 0.234

NC vs PC: 0.075

NC vs MA: 0.323

P value

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DEPARTMENT OF ANIMAL SCIENCE

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Results: morphology and crypt cell proliferation

NC vs PC: 0.115

NC vs MA: 0.489

NC vs PC: 0.681

NC vs MA: 0.732

NC vs PC: 0.929

NC vs MA: 0.996

NC vs PC: < 0.05

NC vs MA: 0.642

P value

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DEPARTMENT OF ANIMAL SCIENCE

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Results: apparent ileal digestibility (AID) of nutrients

NC vs PC: 0.536

NC vs MA: 0.763

NC vs PC: 0.704

NC vs MA: 0.949

NC vs PC: 0.325

NC vs MA: 0.341

NC vs PC: 0.815

NC vs MA: 0.663

P value

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DEPARTMENT OF ANIMAL SCIENCE

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Summary and conclusion

  • Bacitracin showed positive effects on intestinal health and growth performance was rather immediate, whereas the effects of myristic acid were obtained after a 3 week feeding.
  • Myristic acid could be an antibiotic alternative to improve mucosa-associated microbiota, intestinal health, and growth performance of nursery pigs.

NC STATE UNIVERSITY

DEPARTMENT OF ANIMAL SCIENCE

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Thank you!� Thoughts? Questions?

Acknowledgment:

NC STATE UNIVERSITY

DEPARTMENT OF ANIMAL SCIENCE