Evaluation of Antibiotic Alternatives for Nursery Pigs - Dr. Nick Gabler, Iowa State University, from the 2017 Iowa Pork Congress, January 25-26, Des Moines, IA, USA. More presentations at http://www.swinecast.com/2017-iowa-pork-congress

1. Department of Animal Science
Evaluation of (Growth Promoting)
Antibiotic Alternatives for Nursery
Pigs
Nicholas Gabler, Ph.D.
Iowa Pork Congress
January 26, 2017

2. Department of Animal Science
Introduction
• Antibiotics have been used in animal feed for about
50 years
• Anti-microbial agent
• Growth-promoting agent and improvement in
performance
• Chlortetracycline, procaine penicillin,
oxytetracycline, tylosin, bacitracin, neomycin
sulfate, streptomycin, erythromycin, linomycin,
oleandomycin, virginamycin, and bambermycins
have been common feed additives for livestock and
poultry

3. Department of Animal Science
FDA approved antibiotic use
1. Disease treatment
2. Disease control
3. Disease prevention
• Therapeutic use for treating clinically sick
animals, preventing or reducing the incidence of
infectious disease agents

4. Department of Animal Science
Kent Schwartz (2016)

5. Department of Animal Science
FDA disapproved antibiotic use (2017)
• FDA medically important antibiotics
• Same, or in same classes, as antibiotics used to treat humans
• Possible exceptions
• Bacitracin
• Mecadox?
• Narasin
• Bambermycin
• Tiamulin
• Growth Promotion or Improvement of Nutritional Efficiency
• Increasing feed efficiency
• Improving growth rates
• Antibiotic growth
promoters (AGPs)
• Administered at a low,
sub-therapeutic dose

6. Department of Animal Science
Guidance for Industry #209
• “Production uses” (growth promotion and nutritional
efficiency) of antibiotics in classes used in human
medicine are injudicious
• Requires the use of these classes of antibiotics be
under “veterinary oversight”
• “Judicious use”

7. Department of Animal Science
AGPs
• All swine antibiotics are affected under Guidance
#209
• Exceptions for AGPs for in feed and water use
• Bacitracin
• Carbadox
• Bambermycin
• Ionophores
• Tiamulin

8. Department of Animal Science
Potential implications of antimicrobials
on animal physiology
• Optimal animal health
depends on host and
microbial attributes
• AGPs have
1) Indirect effects through
the microbiota
2) Direct effects on the
host
• The functional and
interactive effects of AGPs
on the host and the
microbiota are less clear
International Journal of Antimicrobial Agents,
Volume 49, Issue 1, 2017, 12–24
http://dx.doi.org/10.1016/j.ijantimicag.2016.08.006

9. Department of Animal Science
International Journal of Antimicrobial Agents,
Volume 49, Issue 1, 2017, 12–24
http://dx.doi.org/10.1016/j.ijantimicag.2016.08.006
AGPs function:
B. AGPs may function by
altering the composition
of the microbiota to
reduce competition for
nutrients and/or by
reducing pathogen load
(bacteria-centric
hypothesis)
C. Direct immunomodulatory
agents that allow for
resources to be shifted to
metabolic functions (i.e.
host-centric hypotheses)
The intestinal
mucosa is a dynamic
surface central both
to metabolic and
immune
homeostasis

10. Department of Animal Science
FEED GRADE AGP
ALTERNATIVES STUDY
(PRELIMINARY DATA- ISU/USDA NADC)
M. Schroyen, J. Trachsel, S. Curry, H. Allen, C. Tuggle,
C. Loving, E. Burrough, N. Gabler

11. Department of Animal Science
Post-weaned performance (5 weeks)
Diet ADG, kg ADFI, kg G:F
Control 0.32a 0.37a 0.88
CTC 0.43b 0.51b 0.85
5% inulin 0.37ab 0.44ab 0.87
5% Resistant Starch (RS) 0.40b 0.46ab 0.87
0.25% Butyrate 0.36ab 0.42ab 0.88
-1
1
3
5
7
9
11
13
15
0 1 2 3 4 5 6
DeltaBW,kg
Week
Control
CTC
5% inulin
5% RS
0.25%
Butyrate

12. Department of Animal Science
Cecal SCFA

13. Department of Animal Science
DEVELOPMENT AND
VALIDATION OF A
STANDARDIZED SCIENTIFIC
PROTOCOL EVALUATING
ANTIBIOTIC ALTERNATIVES IN
GROWING PIGS
(NPB# 15-204)

14. Department of Animal Science
Project Team
• Iowa State University
• Nicholas Gabler (AnS)
• John Patience (AnS)
• Kent Schwartz (VDL)
• Chris Rademacher (VDPAM)
• Alex Ramierez (VDPAM)
• Daniel Linhares (VDPAM)
• Wes Schweer (AnS)
• Kristin Olsen (AnS)
• USDA-NADC
• Heather Allen
• Crystal Loving

15. Department of Animal Science
Project Objectives
• To develop a framework within which studies on alternatives
to antibiotic growth promotants may be conducted
1. To develop a protocol that defines the critical and
essential components that can be used to undertake
studies on alternatives of antibiotic growth promoters,
such that results will be clear and definitive and can be
compared to other studies on the same topics.
• This protocol will have sufficient detail to achieve this
objective but also have sufficient flexibility and framework
to apply to a broad range of experimental approaches and
topics
2. To validate the protocol(s) defined by objective 1 by
undertaking a study in nursery pigs to provide data on
options for AGP replacement in nursery diets

16. Department of Animal Science
Proposed outcomes for the NPB
• An extensive review of nursery-finisher studies, including
methodologies and designs that will be utilized to construct a
standardized experimental protocol that identifies the essential
requirements of an effective evaluation of alternatives to AGPs
• The results of a validation study to test the adequacy and efficacy
of the proposed standardized protocol
• Data on different approaches to replacing AGPs – i.e. organic
acids, pre- or pro-biotics and specific diet formulations.
• The validation phase will not only confirm the validity of the
standard protocol but it will also provide useful data on the topic of
interest

17. Department of Animal Science
Search term into database
Remove duplicates, keep only journal articles since 1990
Exclude articles that didn’t contain performance data or
mortality in abstract
Keep articles in English with full text available

18. Department of Animal Science
Search Parameters
• Databases used:
• Pubmed
• Sciencedirect
• Web of Science
• CAB Abstracts
• Agricola
• Searched all years for initial search

19. Department of Animal Science
Search Parameters
Category Search Term
Probiotic probiotic AND swine(pig)
Prebiotic prebiotic AND swine
Oligosaccharide oligosaccharide AND swine AND wean
Organic Acids (“organic acid”) OR (“organic acids”) AND swine
Essential oils /
botanicals /
plant extracts
essential oil AND swine
botanical AND swine
plant extract AND swine AND wean
Yeast yeast AND swine AND wean
Resistant
starch/ fiber
starch AND swine AND wean
fiber AND swine AND wean
Zinc/Copper zinc AND swine AND wean
copper AND swine AND wean
Lysozyme lysozyme AND swine

20. Department of Animal Science
Search Parameters
• Export all references to Endnote
• Exclude papers previous to 1990
• Exclude duplicates and keep only research articles
• Read abstracts and keep only articles that report
performance data or mortality
• Obtained full text papers written in English

21. Department of Animal Science
Criteria by which each paper was evaluated
• Challenge (yes/no)
• n/trt
• Exp. Unit
• Pigs/pen
• Age of pig (days)
• Start BW (kg)
• Genetics
• Duration of feeding
(days)
• Diet components
• ADG (-,0,+)
• ADFI (-,0,+)
• Feed Efficiency (-
,0,+)
• Mortality (-,0,+)
• Blood Assay (yes/no)
• Tissue Assay
(yes/no)
• Microbiome (yes/no)

22. Department of Animal Science
Paper Criteria
• If paper included control and multiple treatments,
each treatment considered one experiment
• Example:
• Trts: control, butyric acid, propionic acid,
butyric + propionic acid
• Paper would include 3 “experiments”

23. Department of Animal Science
Probiotics
• Search term: probiotic AND swine
• Total articles: 2,296
• After duplicates + since 1990: 1,629
• Contain performance/mortality: 288
• Articles available: 172
• Probiotic type: Bacillus (39), Bifidobacterium (26),
Enterococcus (27), Escherichia (8), Lactobacillus
(62), Lactococcus (5), Pediococcus (10),
Saccharomyces (12), combo (65), other (5)

24. Department of Animal Science
Probiotics
• 309 total studies
• 46 challenge studies
• ADG: (+) = 172; 0 = 172; (-) = 5; not reported = 10
• ADFI: (+) = 40; 0 = 153; (-) = 10; not reported = 106
• GF: (+) = 78; 0 = 134; (-) = 3; not reported = 94
• Mortality: (+) = 15; 0 = 28; (-) = 0; not reported = 266
• Avg. n/trt: 21.1
• Avg. pigs/pen: 6.0
• Avg. study duration: 35.9 days
• Avg. age: 23.9 days
• Avg. BW: 14.2 kg

25. Department of Animal Science
Probiotic - ADG
Response
#
studies
Start BW
(kg)
Duratio
n (days)
Age (days)
(0) 172 15.1 29.6 23.9
(-) 5 25.7 28.0 44.2
(+) 122 12.9 45.7 23.5
nr 10 5.0 26.2 17.3
Total 309
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 14.6 2 400 8.0 32.5 4.9 1 22 4.0 4.2
(-) 14.0 12 16 15.0 1.7 5.8 1 14 4.0 4.9
(+) 18.5 2 600 6.0 58.4 7.3 1 35 6.0 5.6
nr 165.5 2 1471 10.0 436.2 8.4 1 11 10.5 4.0
No change in
growth
Negative impact on
growth
Positive impact on
growth
Not reported

26. Department of Animal Science
Probiotics - Observations
• No genetic pattern – 44 genetic combinations
• Of 122 (ADG+):
• 37 probiotic combination
• 29 Lactobacillus spp.
• 8/29 = Lactobacillus plantarum
• 20 Bacillus spp.
• 16 Enterococcus spp.
• 15/16 = Enterococcus faecium

27. Department of Animal Science
Prebiotics
• Search term: prebiotic AND swine
• Total articles: 517
• After duplicates + since 1990: 440
• Contain performance/mortality: 53
• Articles available: 39

28. Department of Animal Science
Prebiotics
• 92 total studies
• 7 challenge studies
• ADG: (+) = 10; 0 = 80; (-) = 0; not reported = 2
• ADFI: (+) = 4; 0 = 74; (-) = 1; not reported = 14
• GF: (+) = 10; 0 = 60; (-) = 0; not reported = 23
• Mortality: (+) = 0; 0 = 3; (-) = 0; not reported = 90
• Avg. n/trt: 10.4
• Avg. pigs/pen: 3.9
• Avg. study duration: 28.8 days
• Avg. age: 25.0 days
• Avg. BW: 9.9 kg

29. Department of Animal Science
Prebiotic - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 86 9.0 26.0 23.8
(-) 0 -- -- --
(+) 11 10.9 45.8 21.3
nr 2 9.8 19.0 25.0
Total 99
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 11 2 71 10.0 8.5 3.8 1 11 4.0 2.4
(-) -- -- -- -- -- -- -- -- -- --
(+) 6.8 4 8 7 1.3 4.6 3 10 4.0 2.1
nr 6 6 6 6.0 0.0 1.0 1 1 1.0 0.0

30. Department of Animal Science
Prebiotic – Observations
• No genetic pattern – 7 genetic combinations
• Diets – 5/11 Corn-soy based
• Of 11 (ADG+):
• 3/10 = sorbitol
• 3/10 = lactulose

31. Department of Animal Science
Oligosaccharide
• Search term: oligosaccharide AND swine AND
wean
• Total articles: 485
• After duplicates + since 1990: 376
• Contain performance/mortality: 74
• Articles available: 44

32. Department of Animal Science
Oligosaccharide
• 92 total studies
• 5 challenge studies
• ADG: (+) = 17; 0 = 71; (-) = 4; not reported = 0
• ADFI: (+) = 6; 0 = 58; (-) = 3; not reported = 3
• GF: (+) = 17; 0 = 48; (-) = 0; not reported = 5
• Mortality: (+) = 1; 0 = 5; (-) = 0; not reported = 64
• Avg. n/trt: 10.3
• Avg. pigs/pen: 5.9
• Avg. study duration: 30.6 days
• Avg. age: 22.9 days
• Avg. BW: 7.5 kg

33. Department of Animal Science
Oligosaccharide - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 71 5.3 30.4 25.0
(-) 4 2.1 22.8 24.8
(+) 17 3.6 24.0 18.6
nr 0 -- -- --
Total 92
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 10.7 3.0 50.0 6.0 11.7 6.0 1.0 32.0 5.0 5.3
(-) 7.3 6.0 10.0 6.5 1.6 4.5 1.0 6.0 5.5 2.1
(+) 13.4 3.0 50.0 8.0 12.9 7.4 1.0 12.0 10.0 3.6
nr -- -- -- -- -- -- -- -- -- --

34. Department of Animal Science
Oligosaccharide – Observations
• No genetic pattern – 8 genetic combinations
• Diet – 7/17 Corn-soy based

35. Department of Animal Science
Organic Acids
• Search term: (“organic acid”) OR (“organic acids”))
AND swine
• Total articles: 1,963
• After duplicates + since 1990: 1,573
• Contain performance/mortality: 130
• Articles available: 80

36. Department of Animal Science
Organic Acids
• 154 total studies
• 8 challenge studies
• ADG: (+) = 44; 0 = 84; (-) = 2; not reported = 0
• ADFI: (+) = 17; 0 = 107; (-) = 1; not reported = 5
• GF: (+) = 26; 0 = 101; (-) = 0; not reported = 3
• Mortality: (+) = 10; 0 = 5; (-) = 0; not reported = 115
• Avg. n/trt: 8.5
• Avg. pigs/pen: 6.3
• Avg. study duration: 43.8 days
• Avg. age: 24.3 days
• Avg. BW: 13.0 kg

37. Department of Animal Science
Organic Acids - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 104 13.5 43.5 24.3
(-) 2 8.1 31.5 25.5
(+) 48 14.9 45.6 27.1
nr -- -- -- --
Total 154
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 10.3 2 168 7.0 18.1 5.9 1 34 4.0 6.1
(-) 7.5 5 10 7.5 2.5 4.0 2 6 4.0 2.0
(+) 7.8 3 40 6.0 6.7 7.5 1 20 6.0 5.0
nr -- -- -- -- -- -- -- -- -- --

38. Department of Animal Science
Organic Acids – Observations
• No genetic pattern – 24 genetic combinations
• Diet – 26/48 Corn-soy based

39. Department of Animal Science
Essential oils/botanicals/plant extracts
• Search term: plant extract AND swine AND wean
• Search term: botanical AND swine AND wean
• Search term: essential oil AND swine
• Total articles: 2,608
• After duplicates + since 1990: 1,663
• Contain performance/mortality: 181
• Articles available: 131

40. Department of Animal Science
Essential oils/botanicals/plant extracts
• 334 total studies
• 40 challenge studies
• ADG: (+) = 74; 0 = 243; (-) = 8; not reported = 9
• ADFI: (+) = 34; 0 = 283; (-) = 14; not reported = 44
• GF: (+) = 55; 0 = 221; (-) = 6; not reported = 48
• Mortality: (+) = 1; 0 = 15; (-) = 1; not reported = 313
• Avg. n/trt: 8.4
• Avg. pigs/pen: 5.1
• Avg. study duration: 32.8 days
• Avg. age: 25.6 days
• Avg. BW: 11.2 kg

41. Department of Animal Science
Ess. Oils/Botanicals - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 243 10.3 32.3 24.1
(-) 8 22.5 44.6 22.0
(+) 74 11.6 35.6 25.0
nr 9 25.2 11.3 66.6
Total 334
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 8.1 1 50 6.0 5.6 4.9 1 34 4.0 4.2
(-) 13.8 5 32 10.0 8.8 5.6 1 9 5.5 3.1
(+) 8.3 2 33 6.0 5.4 5.6 1 30 4.0 4.3
nr 11.4 4 15 12.0 2.8 3.6 1 24 1.0 7.2

42. Department of Animal Science
Ess. Oils/Botanicals - Observations
• No genetic pattern – 24 genetic combinations
• Diet – 35/74 Corn-soy based

43. Department of Animal Science
Yeast
• Search term: yeast AND swine AND wean
• Total articles: 782
• After duplicates + since 1990: 426
• Contain performance/mortality: 96
• Articles available: 60

44. Department of Animal Science
Yeast
• 87 total studies
• 12 challenge studies
• ADG: (+) = 22; 0 = 63; (-) = 1; not reported = 1
• ADFI: (+) = 12; 0 = 57; (-) = 1; not reported = 17
• GF: (+) = 10; 0 = 54; (-) = 1; not reported = 22
• Mortality: (+) = 1; 0 = 7; (-) = 0; not reported = 79
• Avg. n/trt: 12.0
• Avg. pigs/pen: 4.9
• Avg. study duration: 25.6 days
• Avg. age: 21.2 days
• Avg. BW: 8.4 kg

45. Department of Animal Science
Yeast - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 63 9.2 22.9 21.6
(-) 1 6.6 28.0 22.0
(+) 22 6.3 31.0 19.1
nr 1 -- 1.0 35.0
Total 87
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 10.5 2 64 8.0 8.9 4.6 1 16 4.0 3.7
(-) 7.0 7 7 7.0 0.0 5.0 5 5 5.0 0.0
(+) 16.3 4 163 8.0 32.4 5.9 1 20 4.0 4.5
nr 15.0 15 15 15.0 0.0 1.0 1 1 1.0 0.0

46. Department of Animal Science
Yeast - Observations
• No genetic pattern – 16 genetic combinations
• Diet – 15/22 Corn-soy based

47. Department of Animal Science
Resistant starch/fiber
• Search term: starch AND swine AND wean
• Search term: fiber AND swine AND wean
• Total articles: 2,432
• After duplicates + since 1990: 1,352
• Contain performance/mortality: 157
• Articles available: 81

48. Department of Animal Science
Resistant starch/fiber
• 203 total studies
• 10 challenge studies
• ADG: (+) = 19; 0 = 148; (-) = 34; not reported = 2
• ADFI: (+) = 12; 0 = 148; (-) = 28; not reported = 15
• GF: (+) = 14; 0 = 137; (-) = 18; not reported = 34
• Mortality: (+) = 2; 0 = 11; (-) = 5; not reported = 185
• Avg. n/trt: 10.8
• Avg. pigs/pen: 3.6
• Avg. study duration: 32.1 days
• Avg. age: 25.3 days
• Avg. BW: 9.7 kg

49. Department of Animal Science
Starch/Fiber - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 148 9.8 32.7 24.5
(-) 34 10.4 33.0 29.4
(+) 19 8.0 26.7 23.2
nr 2 9.8 24.0 40.0
Total 203
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 9.6 2 100 8.0 11.6 3.1 1 14 2.0 2.4
(-) 6.6 3 20 5.0 4.1 2.5 1 8 2.0 1.9
(+) 27.5 2 353 11.0 76.9 9.6 1 37 4.0 12.1
nr 6.0 6 6 6.0 0.0 1.0 1 1 1.0 0.0

50. Department of Animal Science
Starch/Fiber - Observations
• No genetic pattern – 12 genetic combinations
• Diet – no pattern

51. Department of Animal Science
Zinc/Copper
• Search term: zinc AND swine AND wean
• Search term: copper AND swine AND wean
• Total articles: 1,953
• After duplicates + since 1990: 797
• Contain performance/mortality: 167
• Articles available: 123

52. Department of Animal Science
Zinc/Copper
• 495 total studies:
• 38 challenge studies
• ADG: (+) = 211; 0 = 278; (-) = 3; not reported = 3
• ADFI: (+) = 129; 0 = 342; (-) = 5; not reported = 19
• GF: (+) = 100; 0 = 348; (-) = 3; not reported = 44
• Mortality: (+) = 9; 0 = 8; (-) = 0; not reported = 478
• Avg. n/trt: 11.7
• Avg. pigs/pen: 5.1
• Avg. study duration: 30.2 days
• Avg. age: 24.5 days
• Avg. BW: 7.6 kg

53. Department of Animal Science
Zn/Cu - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 278 7.9 28.7 25.2
(-) 3 2.6 20.0 12.7
(+) 211 7.2 32.6 23.7
nr 3 6.9 13.7 20.0
Total 495
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 12.7 1 137 6.0 21.1 4.4 1 28 4.0 3.3
(-) 6.0 2 10 6.0 3.3 8.5 4 13 8.5 4.5
(+) 10.6 1 123 6.0 18.0 6.1 1 21 5.0 4.3
nr 8.0 8 8 8.0 0.0 3.0 1 7 1.0 2.8

54. Department of Animal Science
Zn/Cu - Observations
• No genetic pattern – 47 genetic combinations
• Diet – 140/211 Corn-soy based
• Of 211 (+):
• 142 Zn
• 24/142 = 3000 ppm
• 16/142 = 2500 ppm
• 55 Cu
• 11/55 = 250 ppm
• 10/55 = 200 ppm

55. Department of Animal Science
Lysozyme
• This enzyme functions by attacking peptidoglycans
found in the cell walls of bacteria
• Especially Gram-positive bacteria
• Search term: lysozyme AND swine
• Total articles: 1,618
• After duplicates + since 1990: 867
• Contain performance/mortality: 16
• Articles available: 9

56. Department of Animal Science
Lysozyme
• 9 total studies
• 3 challenge studies
• ADG: (+) = 4; 0 = 3; (-) = 1; not reported = 1
• ADFI: (+) = 1; 0 = 5; (-) = 0; not reported = 3
• GF: (+) = 3; 0 = 3; (-) = 1; not reported = 2
• Mortality: (+) = 0; 0 = 0; (-) = 0; not reported = 9
• Avg. n/trt: 11.0
• Avg. pigs/pen: 6.0
• Avg. study duration: 22.9 days
• Avg. age: 15.0 days
• Avg. BW: 6.4 kg

57. Department of Animal Science
Lysozyme - ADG
Response
#
studies
Start BW
(kg)
Duration (days) Age (days)
(0) 3 4.9 25.7 9.7
(-) 1 5.8 21.0 17.0
(+) 4 6.9 24.5 21.3
nr 1 -- 10.0 4.0
Total 9
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 11.7 6 20 9.0 6.0 2.3 1 5 1.0 1.9
(-) 5.0 5 5 5.0 0.0 4.0 4 4 4.0 0.0
(+) 13.3 5 16 16.0 4.8 10.5 4 25 6.5 8.5
nr 6.0 6 6 6.0 0.0 1.0 1 1 1.0 0.0

58. Department of Animal Science
Lysozyme - Observations
• No genetic pattern – 7 genetic combinations
• Diet –
• 4/9 Corn-soy based
• 3/9 milk/milk replacer

59. Department of Animal Science
Combined Overall Data - ADG
Response # studies
Av. Start
BW (kg)
Av. Duration
(days)
Av. Age
(days)
0 1119 10.1 30.7 24.1
(-) 57 12.2 32.6 28.7
(+) 498 (29%) 9.7 36.2 23.5
nr 24 17.1 16.4 36.9
Total 1698
Response n/trt Pig/pen
Avg Min Max Med Stdev Avg Min Max Med Stdev
(0) 11.0 1 400 7.0 18.1 4.5 1 34 4.0 4.0
(-) 8.2 2 32 6.0 5.5 3.5 1 13 4.0 2.7
(+) 12.8 1 600 6.0 35.7 6.5 1 37 5.0 5.3
nr 74.6 2 1471 11.0 291.9 3.4 1 24 1.0 5.6

60. Department of Animal Science
58
87
81
65
73 72 73
56
33
66
1.5
0.0
4.9
1.5
2.4 1.1
16.7
0.6
11.1
3.4
39
11 14
34 22 25
9
43
44
29
2.2 2.2 0.0 0.0 2.7 1.1 1.0 0.6
11.1
1.4
0
10
20
30
40
50
60
70
80
90
100
%,SignificantADGresponse
(0) (-) (+) nr

61. Department of Animal Science
What’s next?
• Utilizing pivot tables to identify trends, get
perspective of previous studies
• Plan to make Excel file available to search
outcomes
• Identify “good” practices and “must” practices
• May not be blanket practices, can vary
depending on product
• Conduct validation study

62. Department of Animal Science
Conclusions
• Great judicious use of antibiotics
• AGP function is poorly understood
• More complex than just shifting enteric microbiota
populations or alterations in intestinal integrity
• Could have direct and indirect functions
• More comprehensive understanding needed
• Testing (evaluation) protocols for AGP alternatives
are being developed to help find effective
alternatives

63. Department of Animal Science
QUESTIONS?