Benzoic acid as feed additive in pig nutrition: Effects of diet

171 Pages·2009·1.11 MB·English

by  Kathrin Bühler

ETH Library
Benzoic acid as feed additive in
pig nutrition
Effects of diet composition on performance, digestion
and ecological aspects
Doctoral Thesis
Author(s):
Bühler, Kathrin
Publication date:
2009
Permanent link:
https://doi.org/10.3929/ethz-a-005834561
Rights / license:
In Copyright - Non-Commercial Use Permitted
This page was generated automatically upon download from the ETH Zurich Research Collection.
For more information, please consult the Terms of use.
Diss. ETH No 18298

Benzoic acid as feed additive in pig nutrition: Effects of diet
composition on performance, digestion and ecological aspects

A dissertation submitted to
ETH ZURICH

for the degree of
Doctor of Sciences

presented by
KATHRIN BÜHLER
Dipl. Sc. Nat. ETH

born May 2, 1979
citizen of Winterthur ZH

accepted on the recommendation of

Prof. Dr. C. Wenk, examiner
Dr. B. Bucher, co-examiner
Dr. J. Broz, co-examiner

2009
Abbreviations
ADF Acid detergent fibre
AGP Antimicrobial growth promoter(s)
AP Total alkaline phosphatase
BMC Bone mineral content
BMD Bone mineral density
BW Body weight
BW 0.75 Metabolic body weight
CA Crude ash
CP Crude protein (N * 6.25)
d(xy) Apparent digestibility of nutrient xy
DE Digestible energy
DM Dry matter
DWG Daily weight gain
FCR Feed conversion ratio
GE Gross energy
MT Metatarsus
NDF Neutral detergent fibre
NH Ammonia
3
OC Osteocalcin
SCL Serum crosslaps
SD Standard deviation
SEM Maximal standard error of the means
SI Small intestine
VFA Volatile fatty acid(s)

- I -
Abbreviations
Experimental diets:
LPr- Low protein diet without benzoic acid
LPr+ Low protein diet with 1 % benzoic acid
HPr- High protein diet without benzoic acid
HPr+ High protein diet with 1 % benzoic acid

CC Low-P diet without phytase, without benzoic acid
CB Low-P diet without phytase, with 0.5 % benzoic acid
PhyC Low-P diet with 750 U/kg phytase, without benzoic acid
PhyB Low-P diet with 750 U/kg phytase, with 0.5 % benzoic acid

LF- Low fibre diet without benzoic acid
LF+ Low fibre diet with 0.5 % benzoic acid
HF- High fibre diet without benzoic acid
HF+ High fibre diet with 0.5 % benzoic acid

- II -
Tables
Benzoic acid and nitrogen
Table 1.1. Composition of the experimental diets (g/kg).........................................................25
Table 1.2. Analysed nutrient content of the experimental diets per kg diet.............................27
Table 1.3. Daily weight gain (DWG), feed intake and feed conversion ratio (FCR)..............28
Table 1.4. N metabolism (g /kg BW0.75/d) and N digestibility (d(N)).....................................29
Table 1.5. Urinary pH and excretion of hippuric acid.............................................................30

Benzoic acid and phytase I
Table 2.1. Composition of the experimental diets (g/kg).........................................................36
Table 2.2. Analysed nutrient composition of experimental diets fed in experiments A
and B.......................................................................................................................39
Table 2.3. Daily weight gain (DWG) and feed conversion ratio (FCR) in experiment B.......40
Table 2.4. Apparent total tract digestibility of crude protein (d(CP)), energy (d(E)),
phosphorus (d(P)) and calcium (d(Ca)) in experiments A and B...........................42

Benzoic acid and phytase II
Table 3.1. Composition of the experimental diets (g/kg).........................................................50
Table 3.2. Ash (g/kg DM) and mineral content (g/kg DM) in metatarsal bones at 66 kg
(experiment A) and at 108 kg (experiment B) BW................................................57
Table 3.3. Bone mineral density (BMD, mg/cm3) and bone mineral content (BMC,
mg/cm) in the midshaft of the tibia at 66 kg (experiment A) and at 108 kg
(experiment B) BW................................................................................................58
Table 3.4. Bone mineral density (BMD, mg/cm3) and bone mineral content (BMC,
mg/cm) in the distal metaphyse of the tibia at 66 kg (experiment A) and at
108 kg (experiment B) BW....................................................................................59
Table 3.5. Breaking strength (kN) of tibia and metatarsal bones II + III at 66 kg
(experiment A) and at 108 kg (experiment B) BW................................................60

Benzoic acid and dietary fibre
Table 4.1. Composition of the experimental diets (g/kg).........................................................67
Table 4.2. Analysed nutrient content of the experimental diet................................................68
- III -
Tables
Table 4.3. Apparent total tract digestibility of crude protein (d(CP)), energy (d(E)) and
neutral and acid detergent fibre (d(NDF), d(ADF))...............................................71
Table 4.4. Apparent digestibility of nitrogen (d(CP)), energy (d(E)) and neutral
detergent fibre (d(NDF)) in different parts of the gastrointestinal tract at 56
kg BW.....................................................................................................................72
Table 4.5. Total volatile fatty acid (VFA) and concentration of acetic, propionic and
butyric acid at 56 kg BW........................................................................................74

- IV -
Figures
Introduction
Figure 1.1. Nitrogen flow in poultry and swine.........................................................................6
Figure 1.2. Structure of phytic acid............................................................................................8
Figure 1.3. Analytical fractionations used in relation to dietary fibre analysis.......................10
Figure 1.4. Predicted cytoplasmic weak-acid/anion equilibrium.............................................19

Benzoic acid and phytase II
Figure 2.1. Mean (± SE) serum calcium and phosphor concentrations (mmol/l) of the
four groups in experiment A..................................................................................53
Figure 2.2. Mean (± SE) serum alkaline phospatase (AP) activities (U/l) and serum
crosslaps (SCL) and osteocalcin (OC) concentrations (ng/ml) of the four
groups in experiment A..........................................................................................55
- V -
Table of contents
Summary...................................................................................................................................1
Zusammenfassung....................................................................................................................3
General Introduction...............................................................................................................5
Nutrient composition..............................................................................................................6
Nitrogen..............................................................................................................................6
Phosphorus.........................................................................................................................8
Dietary fibre.......................................................................................................................9
Organic acids as feed additives............................................................................................12
Benzoic acid.....................................................................................................................13
Citric acid.........................................................................................................................14
Formic acid......................................................................................................................15
Fumaric acid....................................................................................................................15
Lactic acid........................................................................................................................16
Propionic acid..................................................................................................................16
Sorbic acid........................................................................................................................16
Other acids and acid blends.............................................................................................17
Mode of action..................................................................................................................18
Aim of the study...................................................................................................................20
The influence of benzoic acid and dietary protein level on performance, nitrogen
metabolism and urinary pH in growing-finishing pigs.......................................................21
Introduction..........................................................................................................................22
Materials and methods.........................................................................................................23
Animals and experimental design....................................................................................23
Diets.................................................................................................................................24
Analytical methods...........................................................................................................25
Statistical analysis............................................................................................................26
Results and discussion..........................................................................................................26
Diets.................................................................................................................................26
- VI -
Table of contents
Body weight and pig performance...................................................................................27
N metabolism....................................................................................................................28
Urinary pH and urinary hippuric acid.............................................................................30
Conclusion............................................................................................................................31
Effect of benzoic acid and phytase in low-phosphorus diets on performance and
nutrient digestibility of growing-finishing pigs...................................................................32
Introduction..........................................................................................................................33
Material and methods...........................................................................................................34
Animals and housing........................................................................................................34
Diets and feeding..............................................................................................................34
Collection and analysis of samples..................................................................................36
Statistical analysis............................................................................................................37
Results and discussion..........................................................................................................37
Diets.................................................................................................................................37
Pig performance...............................................................................................................40
Apparent nutrient digestibility.........................................................................................41
Conclusion............................................................................................................................45
Influence of benzoic acid and phytase in low-phosphorus diets on bone parameters in
growing-finishing pigs............................................................................................................46
Introduction..........................................................................................................................47
Material and methods...........................................................................................................48
Animals and housing........................................................................................................48
Diets and feeding..............................................................................................................49
Collection and analysis of samples..................................................................................51
Statistical analysis............................................................................................................52
Results..................................................................................................................................52
Blood parameters.............................................................................................................52
Bone composition.............................................................................................................56
Bone stability....................................................................................................................57
- VII -
Table of contents
Discussion............................................................................................................................60
Conclusion............................................................................................................................63
Influence of benzoic acid in high fibre diets on nutrient digestibility and VFA
production in growing-finishing pigs....................................................................................64
Introduction..........................................................................................................................65
Material and methods...........................................................................................................66
Animals and housing........................................................................................................66
Diets and feeding..............................................................................................................66
Collection of samples.......................................................................................................68
Analytical methods...........................................................................................................69
Statistical analyses...........................................................................................................69
Results and discussion..........................................................................................................70
Pig performance...............................................................................................................70
Apparent nutrient and fibre digestibility..........................................................................70
Volatile fatty acids............................................................................................................73
Conclusion............................................................................................................................75
Concluding Discussion...........................................................................................................76
Performance and digestion...................................................................................................77
Animal health.......................................................................................................................79
Ecological aspects................................................................................................................80
Outlook.................................................................................................................................82
Appendix.................................................................................................................................83
Appendix I: Chemical properties of different organic acids................................................84
Appendix II: Organic acids in animal nutrition – A literature review.................................86
Benzoic acid.....................................................................................................................87
Citric acid.........................................................................................................................90
Formic acid......................................................................................................................95
Fumaric acid..................................................................................................................102
- VIII -