Assessing Lipid Quality and Effects on Swine Health and Performance
G.C. Shurson1, B.J. Kerr2, and A.R. Hanson3
Department of Animal Science, St. Paul, MN1
USDA-ARS, Ames, IA2
Swine Vet Center, St. Peter, MN3
WE NEED TO IMPROVE CALORIC EFFICIENCY OF FEED INGREDIENTS TO ACHIEVE THIS!
Rising feed ingredient prices requires focusing on caloric and nutritional efficiency
Ingredient Mcal NE/kg
$/MT (2005)
$/100 Mcal (2005)
$/MT (2012)
$/100 Mcal (2012)
% Increase
Corn 2.67 65 2.7 298 12.3 456
Soybean meal 2.09 200 10.5 606 32.1 306
Corn DDGS 2.34 50 2.4 309 14.5 604
Wheat middlings 2.12 60 3.1 287 14.9 481
Fat – A-V blend 7.23 300 4.6 936 14.3 311
Source: Woyengo et al. (2014)
• High energy sources that improve G:F
• Help maintain energy intake under heat stress
• Improve palatability
• Improve pelleting
• Reduce dust
• Supply essential fatty acids and fat soluble vitamins
Azain (2001)
Lipids are an important component of swine diets
We need to improve CALORIC EFFICIENCY in pork production systems
• Energy – Most expensive diet component
• Lipids– Most expensive energy source– Highly variable fatty acid content, quality, and energy value
• Feed conversion– Not a good predictor of caloric efficiency
Our Goal - Improve caloric and nutritional efficiency of pork production
2005 2006 2007 2008 2009 20105,0005,5006,0006,5007,0007,5008,0008,5009,0009,500
10,000
Caloric Efficiency, Kcal/kg gain
Source: National Pork Board Industry Productivity Report (2011)
Challenges for optimizing energy value of lipids• Nutritionists want predictability and consistency of feed ingredients
– We need accurate ME/NE values to minimize risk of:
• Over-feeding energy and nutrients
– Lost opportunity to capture full economic value
• Under-feeding energy and nutrients
– Sub-optimal animal performance
– We need to prevent ME/NE losses by:
• Reducing lipid peroxidation before animal consumption
• Reducing metabolic oxidative stress from lipids after consumption
General categories of feed lipids
• Animal fat– Rendered fats from beef or pork by-products
• Titer > 40 = tallow• Titer < 40 = grease• Low titer indicates a higher proportion of unsaturated fatty acids
• Poultry fat
• Blended feed fat– Includes blends of tallow, grease, poultry fat, and restaurant grease– Most restaurant grease is hydrogenated soybean oil blends
• Blended animal and vegetable fats– Includes blends of feed grade animal, poultry, vegetable oils, and/or restaurant grease
but may also contain soap, chemical, and other industrial by-products
• Vegetable soap stock– Includes free fatty acids removed from oil during refining
Challenges with evaluating feed lipids• Price is often not related to energy value
• Composition is highly variable among sources
• Quality of feed lipids is…– Poorly defined relative to energy and feeding value– Highly variable
• Are animal fats a biosecurity concern for swine farms?
How is lipid quality evaluated in the market?
• General trading standards– Titer (minimum)
– Free fatty acids (maximum)
– Moisture, insolubles, unsaponifiables (maximum)
– Color
• Other considerations– Pass the AOM stability test at 20 hrs and peroxide value < 5
– Certified to have NO PCB and pesticide residues
– Contain trace concentrations of heavy metals or other contaminants
– May include specifications for minimum or maximum iodine value
Old and Inaccurate• Titer
• MIU
• FFA
• Color
New and Accurate• ME (kcal/kg)
• Susceptibility to peroxidation
• Predictive tests
• Extent of peroxidation
• Indicator tests
• Fatty acid profile
Are we using the most accurate measures to determine the true value of feed fats and oils?
These are used to establish ingredient price in the market
These should be used to determinenutritional and economic value in swine diets
There is a disconnect between lipid price and value!
Factors that affect ME content of lipids
• Age of pig
• Unsaturated:saturated fatty acids (IV) content
• Free fatty acid (FFA) content
• Fatty acid chain length
• Fatty acid position on glycerol
• MIU content
Fatty acid composition is highly variable among lipid sources
Corn Soybean Lard Palm Tallow0
10
20
30
40
50
60
70
80
90
100
11 10
24
4425
2 4
14
5
19
27 23
4139 36
5451
1010
3
C22:6C22:5C20:5C20:4C22:1C20:1C18:3C18:2C18:1C16:1C22:0C20:0C18:0C16:0C14:0C12:0C10:0C8:0C6:0
Kerr et al. (2015)
Fatty acid composition is highly variable among lipid sources
Soybean Corn Lard Tallow Palm0
50
100
150
200
250
14 1339 48
7881 82
56 4413
132 125
6244
13
Iodine ValueU:S RatioTotal UnsaturatedTotal Saturated
NRC (2012)
ME value of various fats and oils for swine
7,400
7,600
7,800
8,000
8,200
8,400
8,600
8,800
ME, kcal/kg
TallowChoice white greasePoultry fatLardRestaurant greaseCorn oilSoybean oilCanola oilCottonseed oilSunflower oilPeanut oilAnimal-Veg Blend
NRC (2012)
Distillers corn oil use in swine diets
• Significant amounts of distillers corn oil are being used in swine diets– Competitive pricing vs. other feed lipids– Higher ME content vs. other feed lipids– PEDv in the U.S. swine industry
• caused some shift away from using animal protein and fat ingredient sources toward plant based ingredients
• Free fatty acid (FFA) content ranges from < 5% to 15%
• Previous research results suggest that as FFA content increases, ME content decreases for swine
Energy content of distillers corn oil (DCO) with variable free fatty acid (FFA) content for swine
NRC (2012)
Refined Corn Oil
DCO (4.9% FFA)
DCO(12.8% FFA)
DCO(13.9% FFA)
Corn Oil(93.8% FFA)
MIU, % - 1.53 1.91 3.94 2.25 5.60
GE, kcal/kg - 9,423 9,395 9,374 9,263 9,156
DE, kcal/kg 8,754 8,814a 8,828a 8,036b 8,465ab 8,921a
ME, kcal/kg 8,579 8,741a 8,691a 7,976b 8,397ab 8,794a
ATTD of EE2, % - 93.2 94.0 95.0 91.7 92.7
1Apparent total tract digestibility of ether extracta,bMeans within treatment comparisons with different superscript differ (P ≤ 0.05).
Kerr and Shurson (2015)
DE content of fats and oils for swine can be estimated based on FFA and U:S fatty acid content
Constant Young Old
A 36.898 37.890
B - 0.005 - 0.005
C - 7.330 - 8.200
D - 0.906 - 0.515
DE (MJ/kg) = A + B × FFA + C × eD(U/S)
DE (kcal/kg) = A + B × FFA + C × eD(U/S)
0.004184 MJ/kcal
Powles et al. (1993)
Oxidative Stress
AntioxidantsReactive Products
Cellular &Tissue Damage
Lipid peroxidation occurs at several levelsStorage Processing
Ingredient
Dietary
G. I. Tract
Physiological
Metabolic oxidative stress, reduced immune function, energy and nutrient utilization efficiency
↓ PUFA↓ Vitamin E↑ Peroxidation
e.g vitamin E, A, C, and S-amino acidsExogenous Antioxidants
e.g glutathione, vitamin C, and enzymesEndogenous Antioxidants
Hanson (2014)
Range in peroxidation of feed fats and oils used in the feed industry (> 500 samples)
Lipid Peroxide value (meq/kg) TBA (ppm MDA)
Soybean oil < 1 to 80 < 0.1 to 7.2
Palm oil < 1 to 56 0.2 to 7.9
Animal-vegetable blend < 1 to 313 0.2 to 16.5
Animal fat < 1 to 65 0.3 to 11.8
Fish oil 1 to 295 0.4 to 105
Source: Kemin Industries, Inc.
Feeding peroxidized lipids reduces growth performance and metabolic oxidative status
of pigs
Literature summary of the effects of feeding peroxidized lipids on swine growth performance
• Data from 17 published studies– Compared feeding peroxidized lipids vs. unoxidized lipids to swine
• Evaluated only supplemental feed fats and oils– Excluded lipids from feedstuffs (e.g. meat and bone meal, fish meal, etc.)– Diets were isocaloric
• Variables of interest included:– Diet PV meq/kg– Diet MDA meq/kg– ADG, ADFI, and G:F – Serum TBARS and α-tocopherol
• Dependent variables are reported as a % relative to unoxidized lipids (control)
Hanson (2014)
Swine0
20
40
60
80
100
120
% R
elati
ve to
Die
ts C
onta
inin
g U
nox-
idiz
ed Li
pid
11.2% Reduction
Unoxidized lipid = 100%
Growth rate is reduced when feeding peroxidized lipidsto swine
Hanson (2014)
Swine0
20
40
60
80
100
120
% R
elati
ve to
Die
ts w
ith U
noxi
dize
d Li
pid
7.5% Reduction
Unoxidized lipid = 100%
Feed intake is reduced when feeding peroxidized lipidsto swine
Hanson (2014)
Swine0
20
40
60
80
100
120
% R
elati
ve to
Die
ts C
onta
inin
g U
nox-
idiz
ed Li
pid
4.3% Reduction
Unoxidized lipid = 100%
Gain efficiency is reduced when feeding peroxidized lipidsto swine
Hanson (2014) • Serum α-tocopherol 46.3% relative to controls• Serum TBARS 19.7% relative to controls
0.00 5.00 10.00 15.00 20.00 25.00 30.000.0
20.0
40.0
60.0
80.0
100.0
120.0
Dietary PV (mEq/kg) and ADGSwine
PV (mEq/kg diet)
ADG,
% re
lativ
e to
cont
rols
r = - 0.16 P = 0.55
Dietary PV is not correlated with reduced ADG of pigs
TBARS is negatively correlated with reduced ADG of pigs
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.00
20
40
60
80
100
120
TBARS, mg malondialdehyde eq/kg diet
ADG,
% re
lativ
e to
cont
rols r = - 0.63 (P = 0.05)
The science behind lipid peroxidation
Lipids can be easily peroxidized under common processing and storage conditions
Heat
Light
Oxygen
Oxidizing Minerals
Lipid sources high in unsaturated fatty acids are most susceptible to peroxidation
• Most vulnerable fatty acids– Oleic acid (C18:1)– Linoleic acid (C18:2)– Linolenic acid (C18:3)
• Rate of peroxidation increases with the degree of unsaturation– Oleic = 1 × rate– Linoleic = 10 × rate– Linolenic = 100 × rate
Adapted from: Bartosz and Kolakowska (2007)
Peroxidization yields numerous compounds that can have undesirable effects to animals
L• LOO•
LH (new PUFA)
LOOH
O2
→ Products: aldehydes & ketones, ↓
acids & polymers
Modifications of: DNA (e.g. 8-OH-deoxyguanosine) Protein (e.g. carbonyl adducts)
PUFA→Initiation
Propagation
Termination
Many peroxidation products are produced and decomposed at different rates and time points
Peroxides Aldehydes Acids Polymers
Time
Rela
tive
num
eric
al v
alue
0h12h, 87C12L/m
Cano
la o
ilCo
rn o
il
24h, 93C12L/m
36h, 95C12L/m
48h, 95C12L/m
60h, 95C12L/m
72h, 94C12L/m
Color is not a reliable indicator of peroxidation.
Color changes of corn and canola oil during lipid peroxidation
Indicative TestsPeroxide value
Thiobarbituric acid reactive substances (TBARS)
p-Anisidine valueConjugated dienes
TOTOX valueCarbonylsHexanal
2,4-decadienal (DDE)4-hydroxynonenal (HNE)
Triacylglycerol dimers and polymersOxiranes
Non-elutable material
Many analytical procedures can be used to measure SOME of the peroxidation products
Predictive TestsActive oxygen method
Oil stability indexOxygen bomb method
corn oil canola oil
poultry fat
beef tallow
0
50
100
150
200
250
300
Peroxide ValueTBARSAnisidine Value
Chan
ge re
lativ
e to
uno
xidi
zed
lipid
corn oil canola oil
poultry fat
beef tallow
Peroxide ValueTBARSAnisidine Value
96° C for 72 h 185° C for 7 h
Peroxidation measures are influenced by lipid fatty acid composition and heat treatment
Liu et al. (2012)
Which peroxidation measures should we use?
• None of the current analytical procedures provide a complete and accurate assessment of peroxidation
• Rate and amount of peroxidation varies with:
– heating conditions (time and temperature)
– depends on fatty acid composition of lipids
Are we doing enough to protect the value of feed fats and oils?
Impact of antioxidants on lipid peroxidation of DDGS and distiller’s corn
oil stored under extreme temperature and humidity conditions
Hanson et al. (2015)
Adapted from: Bartosz & Kolakowska (2007)
Antioxidants inhibit chain reactions of lipid peroxidation
LOO• + LOOHα - T•
α – tocopherol (Vitamin E) Vit. C
LOH
GPX
GSH
GSSG
GPX = glutathione peroxidase• selenium
GSH = glutathione• cys, glu, gly
GSR = glutathione reductase• riboflavin
GSR
Low oil (RO) DDGS5% crude fat18 batches
High oil (HO) DDGS13% crude fat
18 batches
DCO (DCO-HI)MIU = 1.76%18 batches
DCO (DCO-LO)MIU = 1.31%18 batches
No Antioxidant
n = 6
Rendox-CQ® (TBHQ)
1000 ppm fatn = 6
Santoquin-Q4T®
(ethoxyquin + TBHQ)1500 ppm fat
n = 6Each batch split into 3
subsamples for analysis on day 0, 14, and 28
Storage conditions:38⁰ C
94% Relative humidity
Series105
10152025
HO-DDGSRO-DDGSDCO-HIDCO-LO
PV m
eq/k
g oi
lPeroxide value, TBARS, and anisidine value
increased during storage at 38⁰C
Series10
5
10
15
TBAR
S m
g M
DA e
q/kg
oi
l
d 0 d 14 d 2802468
AnV
Time effect (P < 0.01)Ingredient effect (P < 0.01)Ingredient × time interaction (P < 0.01)
Peroxide valueTBARS
Anisidine valueincreased over
time
Hanson et al. (2015)
PV, meq/kg fat TBARS mg MDA eq/kg fat
0.001.002.003.004.005.006.007.008.009.00
HO-DDGSRO-DDGSDCO-HIDCO-LO
Ingredient effect (P < 0.01)a,bMeans with different letters differ (P < 0.05)
Amount of peroxidation varied among ingredients
a b a b a b a b
Hanson et al. (2015)
PV, meq/kg fat TBARS mg MDA eq/kg fat
AnV0.00
2.00
4.00
6.00
8.00
10.00
12.00
CONRENSAN
Antioxidant effect (P < 0.01) a,bMeans with different letters differ (P < 0.05)
Antioxidants reduced peroxidation in distiller’s corn oil and DDGS
a b c a b b
a b c
Hanson et al. (2015)
Effects of feeding increasing amounts of peroxidized corn oil on growth
performance and antioxidant status of nursery pigs
Hanson et al. (2015)
Experimental procedures
• Refined corn oil was heated at 185⁰C for 12 hrs with 12 L air/min (rapidly peroxidized)
• 128 barrows (BW = 6.3 ± 0.6 kg) were fed 1 of 4 isocaloric diets containing 9% corn oil
• Measured ADG, ADFI, and G:F for 5 wks
• Determined liver and serum selenium and vitamin E concentrations
Hanson et al. (2015)
Diet 1 2 3 4
Unheated corn oil 9 6 3 0
Peroxidized corn oil 0 3 6 9
Measure Unoxidized Rapid Oxidized
PUFA, % 54.9 49.3
Vitamin E, IU/100 g 27.7 23.3
OSI, h at 110⁰C1 10.8 2.2
TBARS, mg MDA eq/kg2 48.3 26.7
Peroxide value meq/kg 1.7 5.7
Anisidine Value 5.3 138.01OSI = oil stability index2TBARS = thiobarbituric acid reactive substances
Analyzed characteristics of corn oil
Hanson et al. (2015)
0 3 6 9 0 3 6 90 3 6 90.00.10.20.30.40.50.60.70.8
kgGrowth performance responses from feeding increasing concentrations of peroxidized corn oil
Linear P = 0.10
Linear P = 0.03
Error bars represent PSEM
8%
4%ADG ADFI Gain:Feed
9 6 3 0
0 3 6 9
9 6 3 0
0 3 6 9
9 6 3 0
0 3 6 9
Unoxidized, %
Peroxidized, %
Caloric efficiency declined linearly (P = 0.03) from 2.4 to 4%
Hanson et al. (2015)
Serum metabolic oxidative status indicators
α-Tocopherol Selenium TBARS
0 3 6 90.00.20.30.50.60.80.9
ug/m
L
0 3 6 90.000.020.040.060.090.110.13
ug/m
LLinear
P = 0.11
0 3 6 90.0
0.2
0.4
0.6
0.8
1.0
uM
Linear P = 0.05
Cubic P = 0.005
Data represent least squares means on day 14 and 35TBARS = thiobarbituric acid reactive substancesError bars represent PSEM
55% 8% 8%
9 6 3 0
0 3 6 9
9 6 3 0
0 3 6 9
9 6 3 0
0 3 6 9
Unoxidized, %
Peroxidized, %
Hanson et al. (2015)
How do we connect measures of lipid peroxidation to predict animal growth performance?
• What measures do we use?
• What is the threshold of peroxidation that reduces animal performance?– Varies by species?– Varies by lipid source?
• Are there long-term metabolic consequences of feeding peroxidized lipids not observed by changes in growth performance?
• Are supplemental antioxidants needed?
Common physiological measures of metabolic oxidation status
• Peroxidation products in biological samples– Hydrogen peroxide (rapidly catabolized)– TBARS and conjugated dienes (non-specific)– MDA, HNE, protein carbonyls, 8-hydroxy-deoxyguanosine, isoprostanes (concern thresholds have not been
established)• Liver damage
– Serum transaminase enzymes • Endogenous antioxidants in serum and liver
– α-tocopherol– Vitamin A– Glutathione– Vitamin C– Glutathione peroxidase– Catalase– Superoxide dismutase
• Increased liver size relative to body weight• Changes in gut barrier function• Changes in gene regulation (PPARα)
– Controls expression of fatty acid oxidative metabolism in many waysKEY POINTS:Multiple measures must be used.Relative importance of individual measures is poorly understood.Limited information on using these measures to predict utilization of lipids in animals.
• Lipids containing high amounts of PUFA are most susceptible to peroxidation
• We need to use different peroxidation measures for different types of lipids due to differences in fatty acid composition
• Peroxidation indicators are affected by time and temperature of heating– PV, DDE, and AnV may be acceptable at low temperatures (95⁰C)– HNE, hexanal, and TBARS are good indicators of peroxidation at high
temperatures (185⁰C)– PV, TBARS, and AnV increased in distiller’s corn oil and DDGS stored at 38⁰C
• Commercial antioxidants are effective in reducing peroxidation by ~50%
Conclusions
• Feeding peroxidized lipids reduces growth performance and increases metabolic oxidation in pigs– Peroxide value is a poor predictor of reduced ADG of pigs
• Feeding increasing levels of peroxidized corn oil linearly reduces ADG and Gain:Feed of nursery pigs– Effects are dose dependent– Caloric efficiency declined 2.4 to 4% with 3 to 9% rapidly peroxidized corn oil
Conclusions
• We need to better understand if changes in metabolic antioxidant indicators relate to reduced growth or compromise animal health over time.– Dietary thresholds for maximum lipid peroxidation need to be established
• How do we relate negative biological effects of peroxidized lipids to price or value?
Conclusions