Trey Kellner - Impact of Dietary Fat Source and Level on Growth, Feed Efficiency, Digestibility, and Carcass Fat Quality

IOWA STATE UNIVERSITY
APPLIED SWINE NUTRITION
OVERVIEW OF THE IMPACTS DIETARY FAT
SOURCE AND INCLUSION LEVEL HAS ON
PORK PRODUCTION
T. A. Kellner, M.S.
Department of Animal Science
Iowa State University, Ames
September 19th, 2016
Allen D. Leman Swine Conference

The role of dietary fat in swine diets
• Energy
Improve barn throughput
Maintain energy intake
 When using lower energy ingredients
 When insults to intake occur
When the cost/lb of gain or the cost/unit of energy
provided is advantageous
• Pork carcass fat quality

Impact of dietary fat source and level on
growth performance1
Kellner et al., 2016
Item
Treatment
SEM
P-value2Corn oil
Choice white
grease
2% 4% 6% 2% 4% 6% FS FL
ME intake, Mcal/d 8.71 8.91 8.77 8.65 8.63 8.74 0.14 0.426 0.890
ADG, lbs. 1.99 2.01 2.03 1.99 1.99 2.04 0.02 0.907 0.266
ADFI, lbs. 5.73 5.67 5.45 5.69 5.50 5.43 0.09 0.325 0.028
Feed to gain ratio 2.88 2.82 2.68 2.86 2.76 2.66 0.01 0.107 <0.001
C.V. (d 0), % 19.7 19.3 19.8 19.0 20.0 20.4 1.1 0.857 0.832
C.V. (d 105), % 8.9 8.8 8.5 8.1 9.3 9.1 0.5 0.799 0.589
Average market
BW, lbs.
308 310 310 308 308 310 1 0.749 0.513
Pig days/number
of head sold
119 119 119 120 119 116 2 0.407 0.417
110 pens (7.53 ft2/pig) and 200 pigs per treatment; Starting BW 70.5 ± 0.9 lbs.
2No significant interaction between fat source and fat level was evident (P > 0.30).

caloric efficiency of carcass gain1,2
5.85 5.76
0
1
2
3
4
5
6
7
8
CO CWG
MEintaketocarcassgain,
Mcal:lb
5.85 5.81 5.76
0
1
2
3
4
5
6
7
8
2% 4% 6%
MEintaketocarcassgain,
Mcal:lb
P = 0.074 P = 0.350
110 pens (7.53 ft2/pig) and 200 pigs/treatment; start BW 70.5 lbs. to end BW 309 lbs.
2No significant interaction between fat source and fat level was evident (P > 0.68).

Impact of dietary fat source and level on apparent
(ATTD) and true total tract (TTTD) digestibility on d 391
Item
Treatment
SEM
P-valueCO CWG
2% 4% 6% 2% 4% 6% FS FL FS × FL
ATTD2
DM, % 77.4 82.0 83.7 78.3 82.0 80.5 0.6 0.048 <0.001 <0.001
GE, % 78.6 82.7 84.2 78.8 82.5 81.1 0.3 0.006 <0.001 <0.001
AEE, % 66.2 74.9 79.2 65.2 75.4 75.7 0.9 0.017 <0.001 0.012
TTTD3
AEE, % 95.0 94.1 93.4 91.6 92.8 92.9 0.8 0.062 0.954 0.395
110 pens (7.53 ft2/pig) and 200 pigs/treatment; start BW 70.5 lbs. to end BW 309 lbs.
2Titanium dioxide was included at 0.40%; Apparent total track digestibility (ATTD; %) of either
AEE, DM, or GE was calculated according to Oresanya et al. (2007).
3True total tract digestibility (TTTD; %) of AEE was calculated by correcting ATTD of AEE for
endogenous fat losses at 20 g of AEE/kg of DM intake (Acosta et al., 2015).

Effects of ad libitum feed intake in thermal neutral conditions (TN)1, pair feeding
in thermal neutral conditions (PFTN)1,2, or heat stress (HS)3, additional inclusion
of no dietary fat (CNTR), 3% tallow (TAL), or 3% corn oil (CO) on energy intake
a,bMeans among treatments with different superscripts differ, P < 0.05
1Constant thermal neutral environment of ~75.2°F.
2Limit-fed based on HS feed intake on the previous day
3Heat stress environment of ~91.4°F between 0800 h to 2000 h and ~82.4°F 2000 h to 0800 h
13.1
9.6 9.5
0
2
4
6
8
10
12
14
16
18
TN PFTN HS
MEintake,Mcal/d
a
b
10.7 10.4 11.0
0
2
4
6
8
10
12
14
16
18
CNTR TAL CO
MEintake,Mcal/d
P < 0.001 P = 0.090
b
27.5% Difference

Effects of ad libitum feed intake in thermal neutral conditions (TN)1, pair feeding in
thermal neutral conditions (PFTN)1,2, or heat stress (HS)3, additional inclusion of
no dietary fat (CNTR), 3% tallow (TAL), or 3% corn oil (CO) on caloric efficiency
5.9
4.6
6.1
0
2
4
6
8
10
TN PFTN HS
MEintake:BWgain,Mcal/lb
ab
a
5.8 5.9 5.7
0
2
4
6
8
10
CNTR TAL CO
MEintake:BWgain,Mcal/lb
P = 0.013 P = 0.654
b

of no dietary fat (CNTR), 3% tallow (TAL), or 3% corn oil (CO) on apparent total
tract digestibility (ATTD) of acid hydrolyzed ether extract (AEE)
60.2 61.4 59.0
30
40
50
60
70
80
90
100
110
120
TN PFTN HS
ATTDofAEE,%
41.6
67.9
71.2
30
40
50
60
70
80
90
100
110
120
CNTR TAL CO
ATTDofAEE,%
P = 0.054 P < 0.001
a
c
b

97.9 98.5 96.7
30
40
50
60
70
80
90
100
110
120
TN PFTN HS
TTTDofAEE,%
97.3 96.3 99.3
30
40
50
60
70
80
90
100
110
120
CNTR TAL CO
TTTDofAEE,%
P = 0.118 P = 0.012
a
b b
of no dietary fat (CNTR), 3% tallow (TAL), or 3% corn oil (CO) on true total
tract digestibility (TTTD) of acid hydrolyzed ether extract (AEE)

Effects of ad-libitum feed intake in thermal neutral conditions (TN), pair-
feeding in thermal neutral conditions (PFTN), or heat stress (HS) on
mRNA abundance in adipose tissue on d 7
a,b Means among treatments with different superscripts differ, P < 0.05
Gene Description
Environment, ΔΔCt
SEM P-valueTN PFTN HS
ACLY ATP citrate lyase 0.30 -0.64 0.21 0.63 0.537
ACSS2
Acyl-CoA synthetase short-chain
family member 2
0.23 -0.38 -0.45 0.72 0.633
ACACA Acetyl CoA carboxylase -0.20 -0.56 0.27 1.25 0.517
FASN Fatty acid synthase -0.42 -0.23 -1.15 0.81 0.249
SCD Stearoyl CoA desaturase 0.48a -0.29ab -2.13b 1.19 0.047
PRKAG1
Protein kinase, AMP-activated,
gamma 1 non-catalytic subunit
0.36 0.02 0.30 1.84 0.889
PLIN1 Perilipin 1 0.35 0.45 -0.85 1.60 0.418
ATGL Adipose triglyceride lipase 0.08a -1.80b 1.15a 0.88 <0.001
HSL Hormone sensitive lipase -0.01b -0.36b 1.54a 1.53 0.041
INSR Insulin receptor -0.39 0.40 -0.02 0.81 0.823

Effects of dietary fat (CNTR), 3% tallow (TAL), or 3% corn
oil (CO) on mRNA abundance in adipose tissue on d 7
a,b Means among treatments with different superscripts differ, P < 0.05
Gene Description
Dietary fat, ΔΔCt
SEM P-valueCNTR TAL CO
ACLY ATP citrate lyase -0.04 0.78 -0.85 0.63 0.201
ACSS2
Acyl-CoA synthetase short-
chain family member 2
-0.81 0.52 -0.33 0.72 0.215
ACACA Acetyl CoA carboxylase 0.15 0.02 -0.66 1.25 0.566
FASN Fatty acid synthase -0.36a 0.20a -1.64b 0.81 0.011
SCD Stearoyl CoA desaturase 0.11a 0.90a -2.94b 1.18 0.002
PRKAG1
Protein kinase, AMP-activated,
gamma 1 non-catalytic subunit
0.69 0.21 -0.22 1.84 0.444
PLIN1 Perilipin 1 0.51 0.90 -1.46 1.60 0.101
ATGL Adipose triglyceride lipase 0.04 0.31 -0.92 0.88 0.258
HSL Hormone sensitive lipase 0.13 0.36 0.68 1.53 0.807
INSR Insulin receptor 0.91 -0.04 -0.88 0.81 0.313

Implications
• Dietary fat is highly digested regardless of level of inclusion
• Sources of dietary fat (even of high quality) with different
degrees of unsaturation, differ in TTTD of AEE and caloric
efficiency that need to be further defined and understood, to
maximize value and economic outcomes
• Adding dietary fat will reduce ADFI and not impact ADG if
energy intake is not limited

Implications
• Heat stress not only impairs energy intake, but reduces
the efficiency of converting dietary energy intake into
body weight gain
• Heat stress suppresses lipids being used as a source of
energy
 Dietary lipids are directed towards deposition and not mobilized for
products and processes
 Concerning, as diets formulated in seasonally warm conditions have a
higher proportion of dietary lipids
• Employment of an unsaturated fat source versus a saturated
fat source had no further advantage in alleviating heat stress

The role of dietary fat in swine diets
• Energy
• Pork carcass fat quality
Carcass iodine value (fatty acid profile)
Belly quality

carcass iodine value
65.4 66.3 67.2 70.2 70.3 72.6
80.0
0
20
40
60
80
100
120
0 3 6 3 6 3 6
Control Tallow CWG Corn Oil
Iodinevalue,g/100g
d d d c c b
a
P-values:
Level < 0.001; Source < 0.001; Level × Source < 0.001

Prediction of carcass iodine value (IV) by iodine
value product (IVP)1
IV = 42.99 + (0.373 × IVP)
R2 = 0.85 P = 0.008 Root MSE = 2.87
1Developed via 10 pens (7.53 ft2/pig) and 200 pigs/treatment; start BW 70.5 lbs. to end BW 309
lbs.
2% CWG
4% CWG
6% CWG
2% CO
4% CO
6% CO
60
70
80
90
100
50 60 70 80 90 100 110 120 130
CarcassIV,g/100g
Dietary IVP (measured)

Prediction of carcass iodine value (IV) by linoleic
acid (C18:2) concentration in the diet
IV = 49.94 + (7.000 × C18:2%)
R2 = 0.95 P < 0.001 Root MSE = 1.69
1Developed via 10 pens (7.53 ft2/pig) and 200 pigs/treatment; start BW 70.5 lbs. to end BW 309
lbs.
2% CWG
4% CWG
6% CWG
2% CO
4% CO
6% CO
60
70
80
90
100
2 3 4 5 6
CarcassIV,g/100g
Dietary C18:2 concentration, %

Effects of marketing pull1 on carcass iodine
value (IV)
77.2 77.2 76.7
50
55
60
65
70
75
80
85
90
d 105 d 117 d 134
CarcassIV,g/100g
P = 0.899
1Difference among pulls was evident for HCW (d 105 = 230.8, d 117 = 228.6, d 134 =
233.7 lbs.; P < 0.001).

Implications
• C18:2 (and C18:3 if using fish oil) can be used as a
predictor of carcass IV in a commercial setting
• Limiting C18:2 dietary concentration or intake is key to
lowering carcass IV
• Under these experimental conditions to meet a carcass
IV standard of 74 g/100 g (Semen et al., 2013)
 Maximum dietary concentration of C18:2 had to be less than
3.4%
 Daily C18:2 intake had to be less than 88 g/d.

Implications
• It is important to note that among the attempts to predict
carcass IV:
 What is consistent is the strong linear relationship between dietary fat
composition and carcass fat composition
 What is not consistent among these attempts is range of carcass IV,
the slope, and the resulting y-intercept
 For example
• To meet a carcass IV standard of 74 g/100 g
– Kellner et al. (2014) found that maximum daily C18:2 intake
needs to be less than 111 g/d
– These data indicate the maximum daily C18:2 intake needs to
be less than 88 g/d

Ongoing research
• What is the actual difference in energy value of dietary fats that differ in
their degree of unsaturation?
 A regression equation will be developed from:
• 14 different dietary fat sources (ranging from highly saturated to highly
unsaturated)
• 128 individually housed pigs
• 2 different stages of growth (mid-nursery and mid-grower)
• An adjustment of total tract gastrointestinal endogenous losses of fat
digestion through feeding of a fat-free diet
 mRNA abundance will be measured in 4 different tissues to determine why
differences in digestion, absorption, and metabolism occur due to different
chemical compositions of dietary fats
Funded by the National Pork Board

Thank you
This research was supported by National Research Initiative
Competitive Grant no. 2011-68004-30336 from the USDA National
Institute of Food and Agriculture and the National Pork Board.
Appreciation is expressed to Swine Graphics Enterprises and Gourley
Research Group for in-kind support or contributions.

Trey Kellner - Impact of Dietary Fat Source and Level on Growth, Feed Efficiency, Digestibility, and Carcass Fat Quality

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