influence of feed efficiency and physiological state …•rumen microbiology, functional and...
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Influence of feed efficiency and physiological state on rumen VFA and microbial profiles in
cattle
S Lam1, J Munro2, J Cant1, L Guan3, M Steele3, F Schenkel1, S Miller1,4,
Y Montanholi2
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Outline
• Introduction
• Hypothesis
• Objectives
• Materials and methods
– Grain-fed study
– Grass-fed study
• Results and discussion
• Conclusion
• Acknowledgements
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Introduction: Industry challenges
30-50% agriculture GHG
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Introduction: Industry challenges
Feed costs
$ Herd cost variation
30-50% agriculture GHG
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Introduction: Feed efficiency
Feed Efficiency
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Feed Efficiency
Introduction: Feed efficiency
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Feed Efficiency
Introduction: Feed efficiency
Milk and colostrum composition (Montanholi et al. 2013)
Blood metabolites and hormones (Kelly et al. 2011, Gonano et al. 2014)
Fertility traits (Awda et al. 2013, Fontoura et al. 2015)
Cardiac physiology (Munro et al. 2016)
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Introduction: Rumen metabolism
% Rumen and reticulum = 75% total digestive tract
Large energetic sink with high energy demand
Area of energy absorption - 75% total VFA
10% of the biological variation of RFI due to digestibility
8
(Baldwin 1980)
(Hungate 1960)
(Richardson and Herd 2004)
(Bergman 1990)
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Introduction: Microbiology
(Doddema 1978; Mathers and Miller 1980; Godfried 1980)
Bacteria (1011 cells/ml) 75% feed particle digestion
Protozoa (104-106 cells/ml)
Ciliate species digesting suspended and colonized feed particles
Fungi (103-104 cells/ml) Fibrolytic particle digestion
Methanogens (104-106 cells/ml)
Methanogen ecology associated with methane emissions
(Guan et al. 2008, Zhou et al. 2009, Hernandez et al. 2012, Carberry et al. 2014) Feed efficiency 9
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(Guan et al. 2008, Hernandez-Sanabria 2012)
75% energy requirements
(Briggs et al. 1957, Bergman et al. 1990)
Feed efficiency
Introduction: Volatile fatty acids (VFA)
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Introduction: Rumen microstructure
High energy diet:
Low energy diet:
(Steele et al. 2012)
Sheep papillae microstructure
Stratum corneum thickness
Energy in diet
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Introduction: Rumen pH
(Kimura et al. 2016) pH = 0
pH = 7
pH = 14
acidic
alkaline
neutral
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Hypothesis
Feed efficiency is associated with energetic processes and the rumen is a highly metabolically active organ. Therefore, the variability in rumen metabolism across feed efficiency phenotypes and dietary treatments may be featured through rumen functional and structural assessments.
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Objectives
Rumen pH
Microbiology
Papillae epithelium
100x
Volatile fatty acids (VFA)
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Microbiology
Papillae epithelium
Volatile fatty acids (VFA)
Objectives
100x
Efficient vs Inefficient Grain-fed animals
Grass-fed animals
Rumen pH
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Feedlot study • 48 crossbred cattle
• Trial length: 112 d
16 Steers
16 Steers
16 Bulls
BW = 531 + 57 kg
Materials: Experimental conditions
BW = 506 + 72 kg
Average BW = 536 + 43 kg
Elora Beef Research Centre
39.4%
15.7%
44.9%
Overall breed composition
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21.2%
23.6%
55.2%
Grass-fed study • 141 crossbred cattle
• Trial length: 124 d
107 heifer calves
Materials: Experimental conditions
BW = 253 ± 38 kg Age = 403 ± 27 d
36 pregnant heifers
BW = 406 ± 42 kg Age = 594 ± 95 d
Overall breed composition
Maritime Beef Test Station 17
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INSENTEC feeding system
*Contains 40% of calcium phosphate, 60% trace mineralized salt
Methods: Diet
Chemical Composition Dry Basis (%)
Dry Matter 53.8
Crude Protein 13.9
Acid Detergent Fibre 10.9
Neutral Detergent Fibre 22.2
Starch 45.0
Total Digestible Nutrients 86.0
Ingredient Composition Dry Basis (%)
High-moisture corn 52.5
Haylage 42.3
Soybean meal 3.5
Premix* 1.7
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GROWSAFE
feeding system *Contains 37.4% of calcium phosphate, 62.7% trace mineralized salt
Methods: Diet
Chemical Composition Dry Basis (%)
Dry matter 36.1
Crude Protein 15.5
Acid Detergent Fibre 29.6
Neutral Detergent Fibre 53.7
Starch 6.5
Total Digestible Nutrients 70.3
Ingredient Composition Dry Basis (%)
Haylage 99.5
Premix* 0.5
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Leanness Body Size
Fatness
Rate of Gain
Methods: RFI models
Grain-fed (R2 = 0.74):
Feed intake = [μ + (β1 x body weight)] + (β2*ADG) - (β3*ribeye area) +
(β4*back fat) – (β5*marbling) + subpopulation + RFI
Leanness Body Size
Fatness
Rate of Gain Grass-fed (R2 = 0.61):
Feed intake = [μ + (β1*body weight)] + (β2*ADG) - (β3*ribeye area) +
(β4*rump fat) – (β5*age) + subpopulation + RFI 20
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Rumen tissue
pH logger insertion Rumen fluid
Methods: Sample collection
End of performance test 5.5+1 d prior slaughter
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Methods: Logger insertion
Rumen pH loggers
T9 LRCpH Data Logger Dascor
Method: esophageal tubing
Recording: 5 minute intervals
(~2,600 data points/animal)
Logger sensor
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Methods: Rumen fluid collection
Method:
Oro-ruminal probe with suction
Evaluating:
Microbiology
Volatile fatty acid profiles
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(Doddema 1978; Mathers and Miller 1980; Godfried 1980)
Bacteria Protozoa Methanogen
10 um
Ruminal fluid DNA analysis:
Method:
Rumen fluid DNA isolation
RT-qPCR
Evaluating:
Methods: Microbiology
Fungi
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Bruker, CP-8400 Autosampler
VFA sample processing
Methods: VFA
VFA molar concentrations
• Acetate
• Propionate
• Butyrate
• Valerate
• Isovalerate
• Isobutyrate
• Caproate
Total VFA concentration
Method:
Evaluated:
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ventral blind
dorsal blind
ventral
Methods: Rumen tissue collection
Method:
Tissue collection
Processed for histomorphology
Evaluating: Papillae epithelial thickness
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Methods: Histomorphometry
Histology traits:
• Stratum corneum
• Papillae width
Base Middle piece Tip 27
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6
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
0:00 2:24 4:48 7:12 9:36 12:00 14:24 16:48 19:12 21:36 0:00
Ru
me
n p
H
Time (hh:mm)
High-RFI- Predicted pH
High-RFI- Observed pH
Methods: pH measurements
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Univariate Normality Procedure
• Skewness, Kurtosis, Anderson-Darling Test
• Transformations
• logarithm
• squared
GLM Select procedure
• Determine model effects
50% Efficient vs. 50% Inefficient
+ -
Methods: Statistical analysis
General Linear Model (GLM) Procedure
• Rumen traits
Partial Least Square procedure
• Determine % contribution to RFI
Yijkl = μ + efficiency groupi + subpopulationj + breedsk + ϵijkl
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Results: Physiological status
Trait (%/total VFA) Heifer calves Pregnant heifers P-value
Acetate 71.68 74.62 <0.01
Propionate 18.30 16.53 <0.01
Isobutyrate 0.97 0.89 0.051
Butyrate 7.29 6.47 <0.01
Isovalerate 0.90 0.90 0.952
Valerate 0.58 0.41 <0.01
Caproate 0.28 0.18 <0.01
Total VFA (µmol/ml) 43.52 37.39 <0.01 30
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Trait (%/total VFA) Heifer calves Pregnant heifers P-value
Acetate 71.68 74.62 <0.01
Propionate 18.30 16.53 <0.01
Isobutyrate 0.97 0.89 0.051
Butyrate 7.29 6.47 <0.01
Isovalerate 0.90 0.90 0.952
Valerate 0.58 0.41 <0.01
Caproate 0.28 0.18 <0.01
Total VFA (µmol/ml) 43.52 37.39 <0.01
Results: Physiological status
Bacteria population
Pregnant heifers
Metabolic activity throughout gestation
(Church, 1988; Drackley et al. 2001)
VFA metabolism and energy demand
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Results: RFI – Microbial profiles
Trait (16s rRNA copy/ml) Inefficient Efficient P-value
Total bacteria 4.3x1011 7.6x1011 <0.05
Methanogen 4.9x109 2.3x109 <0.05
Protozoa 4.3x107 1.5x107 0.18
Fungi 6.3x104 3.8x104 0.37
Trait (16s rRNA copy/ml) Inefficient Efficient P-value
Total bacteria 6.0x1010 5.3x1010 0.16
Methanogen 2.6x107 3.1x107 <0.05
Protozoa 1.2x105 1.6x105 0.30
Fungi 1.3x105 1.9x105 <0.05
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Results: RFI – VFA profiles
Trait (%/total VFA) Inefficient Efficient P-value Inefficient Efficient P-value
Acetate 54.4 54.5 0.97 73.48 72.95 0.55
Propionate 29.0 29.3 0.89 17.25 17.45 0.38
Isobutyrate 1.2 1.0 0.11 0.90 0.95 <0.10
Butyrate 8.9 8.6 0.75 6.81 6.91 0.44
Isovalerate 3.0 2.7 0.41 0.87 0.94 <0.05
Valerate 2.6 2.9 0.29 0.47 0.49 0.43
Caproate 0.4 0.5 0.40 0.22 0.22 0.87
Total VFA (µmol/ml) 78.0 80.3 0.66 38.94 41.83 <0.10 33
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Results: Variance analysis
32.5% 21.5%
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Results: Variance analysis
32.5% 21.5%
25.1%
24.9% 24.9%
25.1% Bacteria
Methanogen
Protozoa
Fungi
24.5%
25.8% 24.1%
25.5%
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44.3% 10.0%
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Results: Variance analysis
25.1%
24.9% 24.9%
25.1% Bacteria
Methanogen
Protozoa
Fungi
24.5%
25.8% 24.1%
25.5%
18.8%
12.5%
15.3% 14.0%
7.6%
16.5%
15.3%
36.2%
8.6% 19.9% 5.5%
9.8%
0.9% 19.0%
32.5% 21.5%
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55.7%
44.3% 10.0%
90.0%
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Papillae width Papillae area Inefficient Efficient P
(µm) Base 110.1 113.4 0.39
Middle 119.5 139.4 <0.05
Tip 125.0 148.4 <0.01
Results: Papillae histomorphometry
ventral blind
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Results: Predicted rumen pH curves
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
6.0
6.2
6.4
6.6
6.8
7.0
7.2
7.4
0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00
Fee
d in
tak
e (
kg
)
Ru
me
n p
H
Time of day (hh:min) 38
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Results: Predicted rumen pH curves
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
6.0
6.2
6.4
6.6
6.8
7.0
7.2
7.4
0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00
Fee
d in
tak
e (
kg
)
Ru
me
n p
H
Time of day (hh:min)
* * *
*
*
*
* *
*
* *
*
* = P < 0.05
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Results: Predicted rumen pH curves
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
6.0
6.2
6.4
6.6
6.8
7.0
7.2
7.4
0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00
Fee
d in
tak
e (
kg
)
Ru
me
n p
H
Time of day (hh:min)
* * *
*
*
*
* *
*
* *
*
* = P < 0.05
40
5.6 < pH < 6.0
93%
Inefficient 4.4% vs Efficient 8.5% P = 0.02
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Summary
Bacteria population
Feed Efficiency
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Bacteria population
Methanogen population
Feed Efficiency
Methanogen population
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Summary
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Bacteria population
Methanogen population
Feed Efficiency
Methanogen population
Total and specific VFA
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Summary
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Bacteria population
Methanogen population
Papillae width
Circadian pH Feed Efficiency
Methanogen population
Total and specific VFA
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Summary
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Conclusions
• Rumen microbiology, functional and structural parameters are important in assessing the underlying digestive biology of feed efficiency
• Dietary treatment has an impact on the relevance of rumen parameters used for indicating feed efficiency
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Conclusions
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Acknowledgements
• Advisor: Dr. Yuri Montanholi
• Colleagues and volunteers
• Technical staff
Yanhong Chen
Tim Caldwell
Elora beef research centre
Maritime beef testing station
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