Enteric Fermentation: origin of gases, variations, predictions and - - PowerPoint PPT Presentation
Enteric Fermentation: origin of gases, variations, predictions and mitigation Michael Blmmel Outline of Presentation Origin of ruminal CO 2 and CH 4 from fermentation products Causes and implications of variations in ruminal CO 2 and CH
Michael Blümmel
Origin of ruminal CO2 and CH4 from fermentation products Causes and implications of variations in ruminal CO2 and CH4 Stochiometry of CO2 and CH4 production Prediction of CO2 and CH4 production in vitro and in vitro Enteric mitigation options
OMTDR SCFA MBP GAS
MBP SCFA GAS Short chain fatty acids (C2, C3, C4) supply energy to host animal Microbial biomass supplies protein to host animal ( but also CHO, lipids) CH4 und CO2 ,losses to rumen Microbes and host animal alike
2 Acetate (2 X C-C)
2 Propionate (2 X C-C-C)
1 Butyrate (1 X C-C-C-C)
Principle: balance of net oxidation values is zero Example 1 mol of SCFA with 0.65a; 0.25p; 0.1b CO2 = a/2 + p/4 + 1.5 * b CO2 = 0.65/2 + 0.25/4 + 1.5 * 0.1 CO2 = 0.54
(see Van Soest, 1994, pp 272 – 275)
15 25 35 45 55 65 75 85 95 105 115 125 15 25 35 45 55 65 75 85 95 105 115 125
Diets and compound feeds N = 38 Components N = 27 Forages and roughages N = 57
y= -3.1 + 1.03x; R
2
= 0.96 Sy.x = 4.2; P < 0.0001
SBM
24 h gas volumes (ml) stoichiometrically calculated 24 h measured gas volumes (ml) after pressure correction
Comparisons of stoichiometrically calculated and observed in vitro gas volumes
(Blümmel et al 1999)
Powerful, simple and inexpensive tool to predict gases from SCFA amount and proportion Generally good agreement between lab / in vitro and in vivo data More complex with substrates/feeds high in protein and anti-nutritive factors Limited application to hindgut fermentation
High Efficiency of Microbial Production (EMP) Low Efficiency of Microbial Production (EMP)
OMTDR OMTDR SCFA MBP GAS
SCFA MBP GAS
Many feeding systems treat microbial production as a constant, despite acknowledged variation in EMP Lack of simple techniques to detect and predict variations in EMP
Mean EMP Range in EMP Stern & Hoover (1979) 30 g MN /OMTDR 10 – 50 g MN / OMTDR Lebzien (1996) 10.3 g MP / MJ MEI 7.1 – 14.0 g MP / MJ MEI
11
Pansen 10 kg Futter mikrobiell abgebaut
8 kg DM intake
Assumptions: EMP Diet 1 = 0.10 and EMP Diet 2 = 0.40 Digestibility 63%
5 kg degraded in the rumen
CO2 : 513 l (1008 g) CH4 : 296 l (211 g) 4.5 kg: C2, C3, C4, CO2, CH4 0.5 kg: Microbial biomass 3.0 kg:C2, C3, C4, CO2, CH4 2.0 kg: Microbial biomass CO2: 324 l (673 g) CH4: 197 l (140 g)
Urine-N
Urine-N
Variations in EMP are real and have significant effects on variations in enteric GHG emissions Maximizing EMP regardless of specific P: E host animal requirement Not applicable to hindgut fermentation How to detect variations in EMP?
OMTDR SCFA MBP GAS
Possible measurements:
MBP = OMTDR – [SCFA + GAS]
linkage exists between this and one
0.65a: 0.25p: 0.10b results in 1. 0.54 mmol CO2 (23.4 mg) 2. 0.31 mmol CH4 ( 5.0 mg) 3. 0.65 mmol a (39.0 mg) 4. 0.25 mmol p (18.5 mg) 5. 0.10 mmol b ( 8.8 mg)
(11.2 mg) 105.9 mg Gas volume: 0.54 mmol CO2 13.8 ml 0.31 mmol CH4
7.9 ml
1.00 mmol CO2BUFF 25.6 ml 47.3 ml SF = 105.9 mg: 47.3 ml = 2.24 mg/ml
(Blmmel et al. 1997
500 mg substrate supplied 325 mg feed degraded as determined by ND- solution treatment (Goering and Van Soest (1970) 130.6 ml gas 87.5 ml gas
EMP 0.1 EMP 0.4
EMP = (325 – [130.6 * 2.2])/325 EMP = 0.12
EMP = (325 – [87.5 * 2.2])/325 EMP = 0.41
175 mg 175 mg
(Blummel et al 1997)
500 mg substrate supplied 325 mg feed degraded as determined by ND- solution treatment (Goering and Van Soest (1970) 130.6 ml gas 87.5 ml gas
EMP 0.1 EMP 0.4
PF = 325 mg/130.6 ml PF = 2.49 mg/ml PF = 325 mg /87.5 ml PF = 3.74 mg/ml
175 mg 175 mg
500 mg substrate 90.8 ml gas 68.5 ml gas
Residue 235.8 mg Residue 236.0 mg Wheat Straw Trifol. Wheat Straw
PF = 264.2 mg / 90.8 ml PF = 2.91 mg/ml PF = 264.0 mg / 68.5 ml PF = 3.85 mg/ml
Comparison of predicted and measured CH
4
production
10 15 20 25 30 35 40 10 15 20 25 30 35 40 NaOH treated straws Untreated straws NH
4
treated straws y=3.8 + 0.82x; R
2 = 0.88; P<0.0001; Sy.x=2.5
CH
4
(l) predicted based on in vitro variables and voluntary feed intake CH
4
(l) measured in respiration chambers
(Blümmel et al 2005)
Relations between digestible organic matter intake and methane production in sheep
100 200 300 400 500 600 700 800 900 5 10 15 20 25 30 35 40 y = 5.6 + 0.037x, R
2
= 0.82, P<0.0001 HOWEVER: 35.4 to 63.7 l/kg DOMI Digestible organic matter intake in sheep (g/d) Methane production in sheep (l/d)
With intake and diet quality known, GHG can be predicted with reasonable accuracy Intake and quality often unknowns, opportunistic, variable in small holder systems
100 150 200 250 300 350 400 17.5 22.5 27.5 32.5 37.5 42.5 47.5 52.5 57.5 62.5 67.5 high concentrate (high propionate) high roughage (high acetate)
Microbial biomass produced per kg feed digested (g/kg) CH4 (l) produced per kg feed digested
Blümmel and Krishna 2003
25
ME required (MJ x 109) Milk (kg/d) Maintenance Production Total 3.61 (05/06) 1247.6 573.9 1821.5 6 (Scenario 1) 749.9 573.9 1323.8 9 (Scenario 2) 499.9 573.9 1073.8 12 (Scenario 3) 374.9 573.9 948.8 15 (Scenario 4) 299.9 573.9 873.9
26
Effect of increasing average daily milk yields on
3 6 9 12 15 0.0 0.5 1.0 1.5 2.0 2.5 Daily milk yield per animal (liter)
Methane produced (Tg)
current herd average milk yield of 3.61 l/d (Blmmel et al. 2009)
1. Feed manipulation (SCFA/ EMP)
Biologically feasible, however, multiple trade-offs involved, economically largely untested, difficult to apply to small holder systems
Feasible and bound to happen. However, important non-technical support required such as credit, insurance, labor issues etc
SCFA Gases MBP EMP = 0.1 EMP = 0.4 1 kg OMTDR SCFA : 562 g 375 g 225 g MBP: 400 g
LEGENDS
(Blmmel et al. 2001)
Gases: 338g 100 g
SCFA Gases MBP EMP = 0.1 EMP = 0.4 1 kg OMTDR SCFA : 611 g 407g 193 g MBP: 400 g
LEGENDS
Gases:289 g 100 g
(Blmmel et al. 2001)
MBP used for energy EMP 0.4 – 0.1 300 g MBP 3.3 MJ from SCFA 2.94 MJ NE (f) 1.94 MJ NE (f) HOWEVER ↑
With intake and diet quality known, GHG can be predicted with reasonable accuracy Intake and quality often unknowns, opportunistic, variable in small holder systems
2 4 6 8 10 12 14 16 18 20 22 24
17 18 19 20 21 22 23 24 25 D I (0.778) D II (0.788) D III (0.817) D IV (0.780) D V (0.830)
25 g N: kg OM LEGENDS Release of N: OM during 24 hrs Ratio N: OM
Release of N and OM during 24 hrs incubation in five iso-nitrogenous diets
0.76 0.77 0.78 0.79 0.80 0.81 0.82 0.83 0.84 0.85 0.86 30 31 32 33 34 35 36 37 38 y = - 29.3 + 78.8 x; R
2
= 0.89; P = 0.02 Synchronization Index Efficiency of microbial production ( g MBP/100 g OMTDR) in sheep)