Influence of feed efficiency and physiological state on rumen ... - EAAP

1

2

3

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

4

Outline • • • •

Introduction Hypothesis Objectives Materials and methods – Grain-fed study – Grass-fed study

• Results and discussion • Conclusion • Acknowledgements 2

Introduction: Industry challenges 30-50% agriculture GHG

3

Introduction: Industry challenges 30-50% agriculture GHG Feed costs

$

Herd cost variation

4

Introduction: Feed efficiency

Feed Efficiency

5

Introduction: Feed efficiency

Feed Efficiency

6

Introduction: Feed efficiency Milk and colostrum composition (Montanholi et al. 2013)

Feed Efficiency

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) 7

Introduction: Rumen metabolism

%

10% of the biological variation of RFI due to digestibility (Richardson and Herd 2004)

Rumen and reticulum = 75% total digestive tract (Baldwin 1980)

Large energetic sink with high energy demand (Hungate 1960)

Area of energy absorption - 75% total VFA (Bergman 1990) 8

Introduction: Microbiology Bacteria (1011 cells/ml) 75% feed particle digestion

Methanogens (104-106 cells/ml) Methanogen ecology associated with methane emissions

Feed efficiency

Fungi (103-104 cells/ml) Fibrolytic particle digestion

Protozoa (104-106 cells/ml) Ciliate species digesting suspended and colonized feed particles

9

(Guan et al. 2008, Zhou et al. 2009, Hernandez et al. 2012, Carberry et al. 2014)

Introduction: Volatile fatty acids (VFA)

75% energy requirements

Feed efficiency (Guan et al. 2008, Hernandez-Sanabria 2012)

10

(Briggs et al. 1957, Bergman et al. 1990)

Introduction: Rumen microstructure Sheep papillae microstructure

Low energy diet:

High energy diet:

Stratum corneum thickness

Energy in diet (Steele et al. 2012) 11

Introduction: Rumen pH pH = 14

alkaline

pH = 7 neutral

acidic

pH = 0

(Kimura et al. 2016)

12

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.

13

Objectives Microbiology

Volatile fatty acids (VFA) Papillae epithelium

100x

Rumen pH 14

Objectives Microbiology

Grain-fed animals

Efficient Papillae epithelium

Volatile fatty acids (VFA)

vs Inefficient Grass-fed animals

100x

Rumen pH 15

Materials: Experimental conditions Feedlot study

Overall breed composition

• 48 crossbred cattle

15.7%

• Trial length: 112 d

39.4% 16 Steers

44.9%

Elora Beef Research Centre

16 Steers

BW = 506 + 72 kg 16 Bulls Average BW = 536 + 43 kg

BW = 531 + 57 kg

16

Materials: Experimental conditions Grass-fed study

Overall breed composition

• 141 crossbred cattle • Trial length: 124 d

23.6% 55.2% 21.2%

107 heifer calves

BW = 253 ± 38 kg Age = 403 ± 27 d

36 pregnant heifers

BW = 406 ± 42 kg Age = 594 ± 95 d

Maritime Beef Test Station

17

Methods: Diet INSENTEC feeding system

Chemical Composition

18

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

*Contains 40% of calcium phosphate, 60% trace mineralized salt

Methods: Diet Chemical Composition

GROWSAFE feeding system

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

*Contains 37.4% of calcium phosphate, 62.7% trace mineralized salt 19

Methods: RFI models Grain-fed (R2 = 0.74): Body Size

Rate of Gain

Leanness

Feed intake = [μ + (β1 x body weight)] + (β2*ADG) - (β3*ribeye area) + (β4*back fat) – (β5*marbling) + subpopulation + RFI Fatness

Grass-fed (R2 = 0.61):

Body Size

Rate of Gain

Leanness

Feed intake = [μ + (β1*body weight)] + (β2*ADG) - (β3*ribeye area) + (β4*rump fat) – (β5*age) + subpopulation + RFI Fatness

20

Methods: Sample collection 5.5+1 d prior slaughter

End of performance test

Rumen fluid

pH logger insertion

Rumen tissue

21

Methods: Logger insertion Rumen pH loggers T9 LRCpH Data Logger Dascor Method: esophageal tubing

Logger sensor

Recording: 5 minute intervals (~2,600 data points/animal)

22

Methods: Rumen fluid collection Method:

Oro-ruminal probe with suction Evaluating:

Microbiology Volatile fatty acid profiles

23

Methods: Microbiology Method: Rumen fluid DNA isolation

RT-qPCR Ruminal fluid DNA analysis:

Bacteria

Protozoa

Fungi

Methanogen

Evaluating: 10 um

24

(Doddema 1978; Mathers and Miller 1980; Godfried 1980)

Methods: VFA Evaluated: VFA molar concentrations • Acetate • Propionate • Butyrate • Valerate • Isovalerate • Isobutyrate • Caproate

Method: VFA sample processing

Bruker, CP-8400 Autosampler

Total VFA concentration 25

Methods: Rumen tissue collection Method:

Tissue collection dorsal blind

Processed for histomorphology

Evaluating: Papillae epithelial thickness

ventral

ventral blind

26

Methods: Histomorphometry Histology traits:

• Stratum corneum • Papillae width

Tip

Middle piece

Base

27

Methods: pH measurements 7.6

7.4

Rumen pH

7.2

7 6.8 6.6

High-RFI- Predicted pH

6.4 High-RFI- Observed pH

6.2 6 0:00

2:24

4:48

7:12

9:36 12:00 14:24 Time (hh:mm)

16:48

19:12

21:36

0:00 28

Methods: Statistical analysis Univariate Normality Procedure

General Linear Model (GLM) Procedure

• Skewness, Kurtosis, Anderson-Darling Test

• Rumen traits

• Transformations • logarithm • squared

Partial Least Square procedure

GLM Select procedure

• Determine % contribution to RFI

• Determine model effects

+

-

50% Efficient vs. 50% Inefficient

Yijkl = μ + efficiency groupi + subpopulationj + breedsk + ϵijkl

29

Results: Physiological status Trait (%/total VFA)

Heifer calves

Pregnant heifers

P-value

Acetate

71.68

74.62