i THE ROLE OF OMEGA-6 TO OMEGA-3 FATTY ACID RATIOS IN SOW DIETS ON ...

161 Pages·2013·1.18 MB·English

by  Laura Eastwood

THE ROLE OF OMEGA-6 TO OMEGA-3 FATTY ACID RATIOS IN SOW DIETS ON
REPRODUCTION, PIGLET PERFORMANCE, FATTY ACID PROFILES,
LACTATIONAL FAT MOBILIZATION AND PIGLET HEALTH POST-WEANING

A Thesis Submitted to the College of
Graduate Studies and Research
in Partial Fulfillment of the Requirements
for the Degree of Doctor of Philosophy
in the Department of Animal and Poultry Science
University of Saskatchewan
Saskatoon, Saskatchewan

By
Laura Eastwood

© Copyright Laura Eastwood, December 2012. All rights reserved.
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PERMISSION TO USE STATEMENT

In presenting this thesis in partial fulfillment of the requirements for a Postgraduate degree from
the University of Saskatchewan, I agree that the Libraries of this University may make it freely
available for inspection. I further agree that permission for copying of this thesis in any manner,
in whole or in part, for scholarly purposes may be granted by the professor or professors who
supervised my thesis work or, in their absence, by the Head of the Department or the Dean of the
College in which my thesis work was done. It is understood that any copying or publication or
use of this thesis or parts thereof for financial gain shall not be allowed without my written
permission. It is also understood that due recognition shall be given to me and to the University
of Saskatchewan in any scholarly use which may be made of any material in my thesis.

Requests for permission to copy or to make other uses of materials in this thesis/dissertation in
whole or part should be addressed to:

Head of the Department of Animal and Poultry Science
University of Saskatchewan
51 Campus Drive
Saskatoon, Saskatchewan S7N 5A8
Canada

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ABSTRACT
A series of experiments was conducted to test the overall hypothesis that reducing the
omega-6 (n-6) to omega-3 (n-3) fatty acid (FA) ratio in sow diets would improve sow
reproductive performance (characterized by increases in numbers and body weight of piglets
born alive and weaned) and would lessen the inflammatory responses of their offspring post
weaning. Diets were wheat/barley based and consisted of a control (tallow based, similar to a
standard production diet), 3 diets with plant oil based n-6:n-3 ratios (9:1P, 5:1P, and 1:1P) and a
5:1 fish oil diet (5:1F). The control diet had a ratio of 8:1, but contained approximately half the
polyunsaturated FA content of the other diets. Sows were randomly assigned to a treatment diet
on d 80 of gestation, and remained on that treatment for three consecutive reproductive cycles
(gestation/lactation 1 = P1, gestation/lactation 2 = P2, gestation/lactation 3 = P3).
Experiment 1 was designed to test the hypothesis that reducing the n-6:n-3 FA ratio in
sow diets would increase circulating concentrations of n-3 FA’s in sows and in their offspring,
and the passive immune status of piglets would be improved. Performance data was collected
throughout P1 and P2 on 150 sows (n = 30/diet). Sow and piglet serum, colostrum and milk were
analyzed for FA profiles, and colostrum and piglet serum were analyzed for immunoglobulin (Ig)
A and IgG. In P1, birth weights were unaffected by diet (P > 0.05). Average piglet weaning
weights (P = 0.02) and ADG (P = 0.01) however, were highest for piglets born to sows
consuming the 9:1P and 5:1P diets. During P2, 5:1F sows consumed 10% less feed (P = 0.04),
their piglets had reduced birth weights (P = 0.05), and average weaning weight was reduced by
0.8 kg (P = 0.04) relative to control or 5:1P sows. Colostral and piglet plasma IgA and IgG were
unaffected by diet (P > 0.05). Colostrum FA profile patterns were similar to that of the sow diets.
Serum n-3 FA’s were greatest in sows (P < 0.01) and piglets (P < 0.01) consuming 1:1P or 5:1F
diets. Serum α-linolenic acid (ALA) was highest in the 1:1P sows and eicosapentaenoic acid
(EPA) and docosahexaenoic acid (DHA) were highest in the 5:1F sows. In piglet serum obtained
prior to suckling, ALA and DHA did not differ among treatments (P > 0.05) but EPA was 2.5
times greater in the 1:1P group and 4 times greater in the fish group (P < 0.01) compared to those
from the control diet. In post-suckle samples, ALA was highest in serum from 1:1P diet piglets
(P < 0.01), and EPA and DHA were highest in piglet serum from the 5:1F sows (P < 0.01).
Omega-3 FA’s can perturb lipid metabolism, specifically increasing the lipolytic activity
of adipose tissue and thus the second experiment tested the hypothesis that high producing sows,
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consuming reduced n-6:n-3 ratios would have increased body fat mobilization. Twenty sows per
diet, farrowing ≥ 11 piglets and nursing ≥ 10 piglets during P3, were used. Performance data on
sows and piglets (such as weights, numbers, backfat changes) was collected throughout lactation
and milk samples obtained on d 4 and d 16 of lactation. Jugular catheters were inserted into 8
sows from each of the 9:1P and 1:1P groups on d 5 of lactation and sows were challenged with a
single injection of epinephrine followed by serial blood collections. Feed intake was highest for
sows consuming the control (8.4 kg/d) and 5:1P (8.2 kg/d) diets and lowest for the sows fed the
1:1P (7.4 kg/d) and 5:1F (7.7 kg/d) diets (P = 0.05). Altering the n-6:n-3 FA ratio did not affect
sow BW, piglet ADG, milk DM and N content or the total output of milk (P > 0.2). Sows
consuming the 1:1P diet had greater backfat thickness (P < 0.05) and numerically higher plasma
NEFA at baseline compared with the 9:1P sows (240 vs 93 uM; P = 0.16). When given
epinephrine, 9:1P fed sows tended to have lower net incremental area under the curve (niAUC)
glucose (P = 0.08) and numerically higher niAUC NEFA (P = 0.17) and glycerol (P = 0.15).
A third experiment was conducted to test the hypothesis that piglets raised by sows
consuming reduced n-6:n-3 ratios would have reduced inflammatory responses post-weaning.
Piglets (n = 20/diet) raised by sows consuming the treatment diets described above for 2
gestation/lactation cycles (P2) were selected at weaning. Within diet group, pigs were
randomized to either a challenge control group (saline injected) or to a lipopolysaccharide (LPS)
injected group (n=10/challenge·diet-1). Piglets were fed a common starter diet for 6 days
followed by saline or LPS injections on d 7. Rectal temperatures were recorded for 24 hrs and
blood samples were collected at 0, 2, 6 and 12 hrs post injection for pro-inflammatory cytokine
and blood urea nitrogen (BUN) analysis. Injecting LPS caused decreased feed intake and reduced
ADG (P < 0.01), and increased temperature and cytokine production (P < 0.05). Piglets raised by
sows consuming the 1:1P diet had elevated temperatures (P = 0.01; diet x challenge P > 0.05).
Overall, circulating plasma ALA and EPA were increased in sows and piglets when sows
were fed a 1:1 plant based ratio compared to the control or high n-6:n-3 ratio groups. Sows fed a
ratio of 1:1 mobilized more body fat relative to those consuming the 9:1 ratio; there were no
treatment effects on piglet growth. Reducing maternal n-6:n-3 FA ratios below 5:1 increased
piglet body temperature prior to and during an LPS induced inflammatory challenge,. Reducing
the sow dietary n-6:n-3 FA ratio below 5:1 may have detrimental effects on piglets due to over-
stimulation of inflammatory responses.
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ACKNOWLEDGEMENTS

I would like to express my sincerest thanks to my advisor Dr. Denise Beaulieu for all the
time, effort and guidance provided throughout this endeavour. Additionally, I would like to thank
Dr. Pascal Leterme for his guidance and support as supervisor at the beginning of this venture,
and for his continued support throughout. Without both of you I would not be where I am today.
I would also like to thank my supervising committee, Dr. John Harding, Dr. Murray
Drew, Dr. Phil Thacker and those who have served as committee chair, Dr. Bernard Laarveld,
Dr. Sheila Schmutz and Dr. Fiona Buchanan for your guidance and support. Thank you to Dr.
Nathalie Trottier for taking time out of your busy schedule to serve as my external examiner.
Thanks are expressed to those who provided specific program funding: Vandeputte S. A.,
Alberta Meat and Livestock Agency and the National Pork Board. Additionally, thank you to
those who provide strategic funding to the Prairie Swine Centre: Sask Pork, Alberta Pork,
Manitoba Pork Council and the Saskatchewan Agriculture and Food Development Fund.
Without contributions from all involved this project would not have been possible.
To the Prairie Swine Centre, and all of its wonderful staff and students, I would like to
express my thanks for your friendship and support throughout the last years. Special thanks to
Katie Neufeld, Janice Shea, Raelene Petracek, Doug Gillis and the sow barn staff for all of your
valued help. I could not have made survived the barn work without you. To Jenny Marriott,
thank you for your assistance with thesis preparation and moral support. To Brian Andries,
thanks for letting me interrupt ‘normal’ barn activities for such a long period of time.
To my family, Elaine, Steve, Nicky, Mark, Freda, Steve G, Leslie, Kaden, Samantha,
Matthew, Cameron and Jace, thank you for your unconditional love and support throughout this,
and for believing in me when times got stressful. Without all of you I would not be the person I
am today. To my friends, thank you for keeping me sane and always being there for me when I
needed a break.
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DEDICATION

I would like to dedicate this thesis to my family. To my parents, Elaine and Steve, I am
grateful to have such wonderful, loving parents; my life wouldn’t be what it is today without
you. You have made me who I am today, and I never would have believed I could achieve so
much without your support. To my grandmother Freda, your continual love, encouragement and
support means the world to me. To my siblings Nicky and Mark and your wonderful families, I
don’t know what I would do without you; you are always there to support me and to give me a
laugh when I need it. I love you all very much, and couldn’t be more grateful to be a part of such
a wonderful family.
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TABLE OF CONTENTS

PERMISSION TO USE STATEMENT .................................................................................................................... I
ABSTRACT ................................................................................................................................................................II
ACKNOWLEDGEMENTS ..................................................................................................................................... IV
DEDICATION ............................................................................................................................................................ V
TABLE OF CONTENTS ......................................................................................................................................... VI
LIST OF TABLES .................................................................................................................................................... IX
LIST OF FIGURES .................................................................................................................................................. XI
LIST OF ABBREVIATIONS ............................................................................................................................... XIII
1 GENERAL INTRODUCTION ......................................................................................................................... 1
2 LITERATURE REVIEW .................................................................................................................................. 6
2.1 THE MODERN SOW .......................................................................................................................................... 6
2.2 POLYUNSATURATED FATTY ACIDS .................................................................................................................. 6
2.2.1 Functions in the Body ............................................................................................................................ 8
2.2.1.1 Eicosanoids ....................................................................................................................................................... 8
2.2.1.2 Reproduction ................................................................................................................................................... 10
2.2.1.3 Immunity ......................................................................................................................................................... 11
2.2.1.4 Energy Source ................................................................................................................................................. 12
2.2.2 Omega-3’s & Omega-6’s ..................................................................................................................... 12
2.2.2.1 Dietary Sources ............................................................................................................................................... 13
2.2.2.2 De Novo Synthesis of Long Chain PUFA’s and the Importance of the n-6:n-3 Ratio ..................................... 13
2.3 PUFA’S IN SWINE RATIONS ........................................................................................................................... 14
2.3.1 The Sow ................................................................................................................................................ 15
2.3.2 The Piglet ............................................................................................................................................. 18
2.4 LIPOPOLYSACCHARIDE BIOASSAY ................................................................................................................. 19
2.5 CYTOKINE ASSAYS ........................................................................................................................................ 19
2.6 SUMMARY ...................................................................................................................................................... 20
3 HYPOTHESIS & OBJECTIVES ................................................................................................................... 22
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4 EFFECTS OF ALTERING THE OMEGA-6 TO OMEGA-3 FATTY ACID RATIO IN SOW DIETS
ON REPRODUCTIVE PERFORMANCE, SERUM AND COLOSTRUM FATTY ACID PROFILES, AND
THE CONVERSION OF Α-LINOLENIC ACID INTO EICOSAPENTAENOIC ACID .................................. 24
4.1 ABSTRACT...................................................................................................................................................... 24
4.2 INTRODUCTION .............................................................................................................................................. 26
4.3 MATERIALS AND METHODS ........................................................................................................................... 27
4.3.1 General ................................................................................................................................................ 27
4.3.2 Animals and Housing ........................................................................................................................... 27
4.3.3 Treatments and Feeding ...................................................................................................................... 29
4.3.1 Experimental Procedure ...................................................................................................................... 34
4.3.2 Analytical Methods .............................................................................................................................. 35
4.3.3 Calculations & Statistics ..................................................................................................................... 37
4.4 RESULTS ........................................................................................................................................................ 38
4.5 DISCUSSION ................................................................................................................................................... 56
4.6 CONCLUSIONS ................................................................................................................................................ 62
5 EFFECTS OF ALTERING THE OMEGA-6 TO OMEGA-3 FATTY ACID RATIO IN SOW DIETS
ON BODY FAT MOBILIZATION DURING LACTATION IN HIGH PRODUCING SOWS ........................ 63
5.1 ABSTRACT...................................................................................................................................................... 63
5.2 INTRODUCTION .............................................................................................................................................. 65
5.3 MATERIALS AND METHODS ........................................................................................................................... 66
5.3.1 General ................................................................................................................................................ 66
5.3.2 Animals and Housing ........................................................................................................................... 66
5.3.3 Treatments and Feeding ...................................................................................................................... 67
5.3.4 Experimental Procedure ...................................................................................................................... 68
5.3.5 Analytical Methods .............................................................................................................................. 71
5.3.6 Statistics ............................................................................................................................................... 72
5.4 RESULTS ........................................................................................................................................................ 73
5.5 DISCUSSION ................................................................................................................................................... 85
5.6 CONCLUSIONS ................................................................................................................................................ 89
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6 EFFECTS OF ALTERING THE OMEGA-6 TO OMEGA-3 FATTY ACID RATIO IN SOW DIETS
ON THE INFLAMMATORY RESPONSES OF THEIR OFFSPRING POST-WEANING WHEN
CHALLENGED WITH E. COLI LIPOPOLYSACCHARIDE ............................................................................. 90
6.1 ABSTRACT...................................................................................................................................................... 90
6.2 INTRODUCTION .............................................................................................................................................. 92
6.3 MATERIALS AND METHODS ........................................................................................................................... 93
6.3.1 General ................................................................................................................................................ 93
6.3.2 Animals and Housing ........................................................................................................................... 93
6.3.3 Treatments and Feeding ...................................................................................................................... 94
6.3.4 Experimental Procedure ...................................................................................................................... 95
6.3.5 Analytical Methods .............................................................................................................................. 97
6.3.6 Statistics ............................................................................................................................................... 98
6.4 RESULTS ........................................................................................................................................................ 99
6.5 DISCUSSION ................................................................................................................................................. 108
6.6 CONCLUSIONS .............................................................................................................................................. 112
7 GENERAL DISCUSSION & CONCLUSIONS .......................................................................................... 113
8 IMPLICATIONS ........................................................................................................................................... 120
9 LIST OF REFERENCES .............................................................................................................................. 121
10 APPENDIX A ................................................................................................................................................. 137
11 APPENDIX B ................................................................................................................................................. 140

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LIST OF TABLES

TABLE 4.1A: COMPOSITION OF GESTATION SOW DIETS ................................................................................................. 30
TABLE 4.1B: FATTY ACID PROFILE OF GESTATION SOW DIETS ...................................................................................... 30
TABLE 4.2A: COMPOSITION OF LACTATION SOW DIETS ................................................................................................. 31
TABLE 4.2B: FATTY ACID PROFILE OF LACTATION SOW DIETS .................................................................................... 313
TABLE 4.3: AVERAGE DAILY FATTY ACID INTAKES IN GESTATION AND LACTATION DURING PERIOD 2 ......................... 40
TABLE 4.4: REPRODUCTIVE PERFORMANCE OF SOWS CONSUMING DIFFERING DIETARY N-6 TO N-3 RATIOS DURING
PERIODS 1 AND 2 ................................................................................................................................................. 41
TABLE 4.5: IGA AND IGG CONCENTRATIONS IN COLOSTRUM AND PIGLET PRE- AND POST-SUCKLE SERUM SAMPLES ... 44
TABLE 4.6: FATTY ACID PROFILE OF COLOSTRUM SAMPLES COLLECTED DURING FARROWING ..................................... 46
TABLE 4.7: FATTY ACID PROFILE OF EARLY LACTATION MILK SAMPLES....................................................................... 47
TABLE 4.8: FATTY ACID PROFILE OF LATE LACTATION MILK SAMPLES ......................................................................... 48
TABLE 4.9: FATTY ACID PROFILE OF SOW SERUM COLLECTED ON D 110 (±2) OF GESTATION ........................................ 49
TABLE 4.10: FATTY ACID PROFILE OF PRE-SUCKLE PIGLET SERUM COLLECTED AT FARROWING ................................... 51
TABLE 4.11: FATTY ACID PROFILE OF POST-SUCKLE PIGLET SERUM COLLECTED 24 HOURS POST-FARROWING ............ 53
TABLE 4.12: SERUM LONG CHAIN FATTY ACID TO DIETARY ALA (SLC:ALAIN) AND SERUM EPA TO DIETARY
ALA (SEPA:ALAIN) RATIOS IN SOWS AND THEIR OFFSPRING. ........................................................................... 55
TABLE 5.1: ESTIMATED MILK PRODUCTION, DRY MATTER, NITROGEN AND ENERGY IN MILK ....................................... 74
TABLE 5.2: PERCENTAGE DRY MATTER (TOTAL SOLIDS) IN MILK SAMPLES ON DAY 4 AND 16 OF LACTATION .............. 74
TABLE 5.3: EFFECTS OF SOW DIETARY FATTY ACID RATIO ON LITTER SIZE, PIGLET WEIGHT AND GROWTH
THROUGHOUT LACTATION FOLLOWING 11 MONTHS OF DIETARY CONSUMPTION ................................................ 75
TABLE 5.4: EFFECTS OF DIETARY FATTY ACID RATIO ON LACTATION FEED INTAKE FOLLOWING 11 MONTHS OF
DIETARY CONSUMPTION ...................................................................................................................................... 75
TABLE 5.5: BASELINE PLASMA CONCENTRATIONS OF GLUCOSE, NEFA, GLYCEROL, C-PEPTIDE AND LEPTIN IN
LACTATING SOWS FED DIETS CONTAINING N-6:N-3 FATTY ACID RATIOS OF 9:1P OR 1:1P ................................... 77
TABLE 5.6: PLASMA CONCENTRATIONS OF GLUCOSE, NEFA AND GLYCEROL DURING AN EPINEPHRINE CHALLENGE
FOR LACTATING SOWS FED DIETS CONTAINING N-6:N-3 FA RATIOS OF 9:1P AND 1:1P ....................................... 78
TABLE 5.7: PLASMA CONCENTRATIONS OF GLUCOSE AND C-PEPTIDE DURING A GLUCOSE CHALLENGE FOR FASTED
LACTATING SOWS FED DIETS CONTAINING N-6:N-3 FA RATIOS OF 9:1P AND 1:1P .............................................. 82
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