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Effect of source of dietary fat on pig performance, carcass characteristics and carcass fat content, distribution and fatty acid composition
Meat Science 85 (2010) 606–612
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Effect of source of dietary fat on pig performance, carcass characteristics and carcass fat content, distribution and fatty acid composition C.E. Realini a,*, P. Duran-Montgé b, R. Lizardo c, M. Gispert a, M.A. Oliver a, E. Esteve-Garcia c a
IRTA, Monells, Building B–Finca Camps i Armet E-17121 Monells (Girona), Spain CENTA, IRTA Building A–Finca Camps i Armet E-17121 Monells (Girona), Spain c IRTA, Mas de Bover, Ctra. Reus-El Morell Km. 3,8 E-43120 Constantí (Tarragona), Spain b
a r t i c l e
i n f o
Article history: Received 17 June 2009 Received in revised form 18 September 2009 Accepted 11 March 2010
Keywords: Dietary fat Swine Carcass Fatty acids
a b s t r a c t Seventy gilts were used to compare the effect of including 10% tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), a fat blend (FB), or an oil blend (OB) in finishing diets vs. feeding a semi-synthetic diet with no added fat (NF) on pig performance, carcass traits and carcass fatty acid (FA) composition. Carcasses from SFO-fed gilts had greater fat and lower lean compositions than carcasses from T-fed gilts. Gilts fed NF had greater loin fat than FB-fed gilts, and greater flare fat, loin intermuscular fat and fat:lean than T-fed gilts. Bellies from NF-fed gilts had lower lean and higher intermuscular fat and fat:lean than other diets except HOSF. Fat source had minor effects on animal performance, carcass characteristics and carcass fat content and distribution, whereas feeding NF resulted in carcasses and major cuts with higher fat content. Diets rich in polyunsaturated FA (PUFA) did not reduce fat deposition in separable fat depots with respect to monounsaturated FA (MUFA) and saturated FA (SFA). Carcasses from gilts fed NF had a high degree of saturation (40.6% SFA) followed by carcasses of T- and FB-fed gilts. Feeding HOSF, SFO and LO enriched diets elevated the percentages of MUFA (56.7%), n 6 (30.0%) and n 3 (16.6%) PUFA, respectively, whereas carcasses from gilts fed OB had greater percentages of n 3 FA (14.8% n 3, 0.9% EPA, 1.0% DPA, 3.1% DHA) than gilts fed FB (6.72% n 3, 0.1% EPA, 0.4% DPA, 0.1% DHA). Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction The pork industry has made significant efforts to decrease the total amount of fat deposited in pigs through genetics, management and nutrition. At the same time extensive research has been dedicated towards changing the fatty acid composition of pork products to better match processing requirements and dietary recommendations for the human diet. It is generally accepted that fatty acid (FA) composition of porcine adipose tissue is dependent upon the fatty acid profile of the diet (Bee, Gebert, & Messikommer, 2002; Kouba, Enser, Whittington, Nute, & Wood, 2003; Miller, Shackelford, Hayden, & Reagan, 1990; Mitchaotai et al., 2007; Nuernberg et al., 2005). It has also been shown in broilers that diets rich in polyunsaturated fatty acids (PUFA) reduced abdominal fat deposition compared with feeding diets with predominantly saturated or monounsaturated fats (Crespo & EsteveGarcia, 2001, 2002a; Sanz, Flores, Pérez de Ayala, & López-Bote, 1999). Conversely, a majority of the previous research has failed to demonstrate an effect of feeding swine finishing diets formu-
* Corresponding author. Tel.: +34 972 630052; fax: +34 972 630373. E-mail address: [email protected] (C.E. Realini). 0309-1740/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2010.03.011
lated with beef tallow, poultry fat, soybean oil, linseed oil, and sunflower oil on primal cut yields or carcass composition (Apple, Maxwell, Galloway, Hamilton, & Yancey, 2009; Eggert, Grant, & Schinckel, 2007; Enser, Richardson, Wood, Gill, & Sheard, 2000); however, there are a number of other fat sources and combinations of fat sources which may affect swine carcass composition and/or fat distribution. Most fatty acid research has been conducted in individual adipose tissues (subcutaneous, intermuscular and retroperitoneal) and intramuscular fat from different muscles (Longissimus dorsi, Semimembranosus, Biceps femoris, Diaphragama, Masseter), with limited information on the fatty acid composition of the whole carcass (Apple et al., 2009; Flanzy, François, & Rérat, 1970; Lizardo, van Milgen, Mourot, Noblet, & Bonneau, 2002; Metz & Dekker, 1981; Mitchaotai et al., 2007). Therefore, the objectives of this study were to determine the effect of adding approximately 10% of different dietary fat sources (beef tallow, high-oleic sunflower oil, sunflower oil, and linseed oil) and combinations of fat sources (a fat blend of tallow, sunflower oil and linseed oil or an oil blend of fish and linseed oils) compared with a diet with no added fat on pig performance, carcass characteristics, carcass composition and fat distribution, as well as carcass fatty acid composition, of crossbred gilts.
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C.E. Realini et al. / Meat Science 85 (2010) 606–612 Table 2 Fatty acid (FA) content of experimental diets.a
2. Materials and methods 2.1. Animals and diets
Fatty acid (g/kg feed)
T
HOSF
SFO
LO
FB
OB
NF
Experimental procedures were approved by IRTA’s ethical committee. Duroc Landrace gilts were fed a barley-corn-soybean meal-based diet during a pre-experimental period. Seventy gilts (61.8 ± 5.2 kg live weight), divided in two periods, were grouped by blocks based on live weight, and randomly assigned within blocks to one of seven dietary treatments (10 gilts/treatment). Six fat supplemented diets based on barley and soybean were formulated to meet or exceed nutrient requirements for finishing pigs (NRC, 1998). Additionally, a semi-synthetic diet was formulated using purified ingredients and contained no fat (Table 1). Fat supplementation (10% fat) was determined in order to supply an equal amount of digestible fat based on results from previous trials (Duran-Montgé, Lizardo, Torrallardona, & Esteve-Garcia, 2007). Four fat sources and two combinations of fat sources were selected in order to achieve diets with different fatty acid composition (Table 2). Thus, beef tallow (T) was included to have a diet rich in saturated fatty acids (SFA), whereas high-oleic acid sunflower oil (HOSF), sunflower oil (SFO), and linseed oil (LO) were selected to have diets rich in oleic, linoleic and linolenic acids, respectively. The diet formulated with the fat blend (FB: 55% T, 35% SFO and 15% LO) had intermediate levels of the most prominent FA (palmitic, stearic, oleic, linoleic and linolenic acids), and the diet formulated with the oil blend (OB: 40% fish oil and 60% LO) was formulated to contain a high amount of long-chain PUFA because of the elevated levels of these fatty acids in fish oil. Gilts were individually penned and had ad libitum access to their dietary treatment and water during 50 days. Live weight and feed intake were recorded at the
C14:0 C16:0 C16:1 C18:0 C18:1trans C18:1 C18:2, n 6 C18:3, n 3 C20:0 C22:0 C20:5, n 3 EPA C22:6, n 3 DHA C24:0 Sum FA SFAb MUFAb PUFAb PUFA/SFA n 6 n 3 n 6/n 3
3.34 28.7 2.37 22.9 0.23 34.8 14.2 1.90 0.13 0.07 ND ND 0.03 116.8 57.2 36.2 16.1 0.3 14.2 1.9 7.5
0.12 7.87 0.19 4.25 0.10 86.8 21.5 1.29 0.40 1.15 ND ND 0.42 125.6 14.3 87.4 22.8 1.6 21.5 1.3 16.5
0.13 11.2 0.11 5.56 0.27 32.5 73.3 1.26 0.43 1.02 ND ND 0.31 128.0 18.8 33.2 74.5 4.0 73.3 1.3 56.4
0.09 8.21 0.08 3.64 0.06 20.7 26.2 47.1 0.19 0.20 ND ND 0.15 108.1 12.6 21.1 73.4 5.8 26.2 47.2 0.60
1.72 20.0 1.35 12.8 0.27 29.5 26.0 18.9 0.24 0.23 0.02 0.04 0.05 115.4 36.0 30.5 45.2 1.3 26.1 19.0 1.4
1.53 13.0 1.81 4.07 0.10 19.0 21.5 31.2 0.26 0.24 3.88 12.3 0.13 114.7 20.0 20.5 70.8 3.5 22.5 48.3 0.5
ND 0.48 ND 0.14 0.04 0.56 1.38 0.18 0.01 0.01 ND ND ND 4.0 0.6 0.7 1.6 2.7 1.4 0.2 7.0
a T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. b SFA = saturated fatty acids; MUFA = monounsaturated fatty acids; and PUFA = polyunsaturated fatty acids. ND: under detection limit.
beginning of the trial and again three weeks later, as well as at the end of the trail. 2.2. Dietary chemical composition, fat content and fatty acid profile
Table 1 Ingredient and chemical composition of experimental diets.a Ingredient (%)
T
Wheat starch Soybean protein concentrate Sugar beet pulp Molasses Barley Soybean meal 44% Tallowb High-oleic sunflower oilb Sunflower oilb Linseed oilb Fish oilb Calcium carbonate Mineral/vitamin complexc Dicalcium phosphate Sodium chloride L-Lysine
HCl
HOSF
SFO
LO
FB
OB
70.0 14.0 10.1 4.00 62.4 24.1 11.0
63.8 24.1
63.4 24.1
63.7 24.1
63.5 24.1 5.5
63.4 24.1
9.6 10.0
1.61 0.40 0.27 0.22 0.02
1.61 0.40 0.27 0.22 0.02
1.61 0.40 0.27 0.22 0.02
9.7
3.5 1.0
1.61 0.40 0.27 0.22 0.02
1.61 0.40 0.27 0.22 0.02
5.8 3.9 1.61 0.40 0.27 0.22 0.02
1.08 0.40 0.20 0.15 0.04
DL-Methionine
Chemical composition Net energy (M cal kg Crude protein (%) Total lysine (%) Crude fat (%) Ash (%)
NF
Dietary dry matter content, ash, crude fat, and energy were determined according to AOAC (1990), and crude protein was determined following the Dumas method (method No. 968.06; AOAC, 2000) using a nitrogen/protein analyzer (model FP528; Leco, St. Joseph, MI, USA). Feed lipids were extracted following the procedure of Folch, Lees, and Stanley (1957), converted to fatty acid methyl esters using BF3 and methanolic KOH (Morrison & Smith, 1964) and analyzed using GC (model HP-6890; Hewlett–Packard, Avondale, PA, USA) equipped with an automatic injector, using C19:0 as internal standard. Aliquots of 1 ll were injected into a capillary column (30 m 0.25 mm 0.25 lm DB-23 p/n 1222332; Agilent) with cyanopropyl methyl silicone as stationary phase. Column oven temperature was programmed at 170– 210 °C at 2.5 °C/min, 210–240 °C at 5 °C/min, and held at 240 °C for 5 min with 1:100 split. Injector and detector temperatures were maintained at 250 °C. Hydrogen was the carrier gas at a flow rate of 0.5 mL/min. 2.3. Carcass measurements
1
)
2.61 15.6 0.88 12.7 5.03
2.63 15.1 0.88 11.5 4.83
2.65 15.5 0.88 13.4 4.82
2.61 15.9 0.88 11.6 5.09
2.63 15.8 0.88 11.6 5.11
2.60 16.1 0.88 11.5 5.16
2.22 14.1 0.81 0.32 2.93
a T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. b Fat supplemented diets were formulated in order to supply an equal amount of digestible fat based on previous measurements (Duran-Montgé et al., 2007). C About 5000 IU of vitamin A, 1000 IU vitamin D3, 15 mg vitamin E, 1.3 mg vitamin B1, 3.5 mg vitamin B2, 0.025 mg vitamin B12, 1.5 mg vitamin B6, 10 mg calcium pantothenate, 15 mg nicotinic acid, 0.1 mg folic acid, 2 mg vitamin K3, 80 mg Fe, 6 mg Cu, 0.75 mg Co, 60 mg Zn, 30 mg Mn, 0.75 mg I, 0.10 mg Se, and 0.15 ethoxiquin were provided/kg of feed.
Pigs were transported to the slaughter facilities of IRTA-Monells approximately 14 h before slaughter and were held off feed, but not water, during lairage. Gilts (99.8 ± 8.5 kg live weight) were humanely harvested using CO2 stunning following standard procedures of an officially inspected facility. Carcass and flare fat weights and fat and muscle depths were recorded for each carcass within 1 h postmortem using the Fat-O-Meat’er probe (SFK Technology, Denmark). Muscle and fat depths were measured both at the last rib level and between the 3rd and 4th thoracic ribs counting from the last one (60 mm from the mid-line), and percent carcass lean was predicted using the official Spanish equation of Gispert and Diestre (1994). Then, left sides were commercially
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cut and all primal cuts (ham, loin, shoulder, belly, and tenderloin), as well as other fat cuts (including the jowl and belly trimmings), were weighed to obtain cut yields. In addition, hams, loins and bellies were dissected into lean, subcutaneous and intermuscular fat, and bone following the procedure of Walstra and Merkus (1995). The right side of each carcass was reduced into small pieces using a cutting guillotine (Model D, Olot, Spain) and stored frozen at 20 °C before grinding three times through five eyes, 8 mm and 3 mm plates attached to an industrial grinder with 160 mm head (Grinder Cato-PA160, Sabadell, Spain). The ground side was then thoroughly homogenized for 1 min using a mixer before 500-g samples were collected for proximate and fatty acid composition analyses.
ditions. Allee, Romsos, Leveille, and Baker (1972) found that addition of 10% fat to a low-fat diet, regardless of the source, resulted in an increase in daily gain and gain:feed ratio. Dugan, Aalhus, Lien, Schaefer, and Kramer (2001) reported leaner carcasses as a consequence of improved feed efficiency, more lean and less subcutaneous fat in primal cuts of barrows fed 5% vs. 2% canola oil, but no differences in feed efficiency between treatments were noted in gilts. However, a number of researchers have failed to observe an effect of dietary fat sources on growth performance (Bee et al., 2002; Rossi & Corino, 2002). Mitchaotai et al. (2007) reported no difference in daily gain, daily feed intake, feed conversion efficiency, or final body weight between pigs fed 5% T or 5% SFO, whereas Guillevic, Kouba, and Mourot (2009) noted that neither LO nor SFO impacted growth rate or feed intake.
2.4. Ground carcass composition and fatty acid profile Ground carcass samples were analyzed for crude protein as previously described for feed samples, moisture content was determined by freeze-drying in a Liodelta Telstar (Terrassa, Spain) freeze-dryer for 48 h, and ash content was determined by ashing samples in a muffle oven at 525 °C for 3 h (method 923.03; AOAC, 1990). Lipid from ground carcass was determined following the chloroform–methanol procedure of Folch et al. (1957). Extracted lipids were converted to fatty acid methyl esters using BF3 and methanolic KOH (Morrison & Smith, 1964), and analyzed by GC (model HP-6890; Hewlett–Packard, Avondale, PA, USA) using the same conditions described for feed lipid analysis. 2.5. Statistical analysis Data were analyzed using the GLM procedure of SAS (SAS Inst. Inc., Cary, NC) including dietary treatment and period in the model. Live and carcass weights were included in the model as covariates for live animal and carcass data analyses, respectively. The covariate carcass weight was significant (P < 0.05) for most carcass variables except for those expressed as a percentage of the carcass (primal cut yields). Differences in least-squares means among dietary treatments were assessed by the Tukey–Kramer test, with significance determined at P < 0.05. 3. Results and discussion 3.1. Animal performance There were no differences (P > 0.05) among dietary treatments for average daily feed intake, average daily gain and final live weight of gilts (Table 3). Gilts fed FB had an improved (P < 0.05) feed:gain ratio over gilts fed NF (0.42 kg feed kg 1gain) with other dietary treatments being intermediate. The addition of fat/oil in the diet has previously been found to improve feed efficiency (Pettigrew & Moser, 1991; Smith, Tokach, O’Quinn, Nelssen, & Goodband, 1999). De la Llata et al. (2001) indicated that adding 6% fat to corn-soybean meal diets consistently improved feed efficiency of barrows and gilts in all phases of growth under commercial con-
3.2. Carcass characteristics and primal cut yields Carcass characteristics and primal cut yields of gilts fed the different experimental diets are shown in Table 4. Killing out percentage was greater (P < 0.05) for gilts fed NF than gilts fed OB, but there were no differences (P > 0.05) among gilts fed T, HOSF, SFO, LO and FB. In addition, flare fat percentage was greater (P < 0.05) in carcasses of NF-fed gilts than carcasses of T-fed gilts; otherwise, carcass weight, fat depths measured at the last rib and between the 3rd and 4th last ribs, muscle depth measured between the 3rd and 4th last ribs, and estimated lean percentage did not differ (P > 0.05) among dietary fat sources. With the exception that loin yields from gilts fed NF were greater (P < 0.05) than those from gilts fed FB, the percentages of ham, shoulder, belly, tenderloin, and other fat cuts were similar (P > 0.05) among the dietary treatments. These results contradict those of Pettigrew and Moser (1991) and Miller et al. (1990), who reported that adding fat in diets of growing-finishing pigs increased carcass fatness. Moreover, Stahly and Cromwell (1979) and Stahly, Cromwell, and Overfield (1981) observed that backfat depths and carcass fat percentages were increased in pigs fed 5% T, whereas Allee et al. (1972) noted that the addition of 10% corn oil, lard, coconut oil or T not only increased backfat thickness, perirenal fat, and fat trim, but also reduced longissimus muscle area and carcass lean composition when compared to a control diet devoid of fat. On the other hand, results of the present experiment concur with a number of previous studies where dietary fat source did not impact pork carcass traits (De la Llata et al., 2001; Mitchaotai et al., 2007). Nuernberg et al. (2005) fed diets composed of 5% LO or olive oil, and reported no differences in any carcass characteristics between fat sources. Moreover, Bee et al. (2002) fed diets formulated with 5% T or soybean oil, whereas Rossi and Corino (2002) fed diets 3% T, corn oil or rapeseed oil, and neither study demonstrated an effect of fat source on carcass characteristics or subprimal yields. Guillevic et al. (2009) also found no effect of LO or SFO on pork quality or subprimal weights, which is in agreement with results from the present study.
Table 3 Least-squares means for average daily feed intake (ADFI), average daily gain (ADG), final live weight (FLW), and feed:gain ratio of gilts fed experimental diets.A
ADFI (kg d 1) ADG (kg d 1) FLW (kg) Feed:gain a,b
T
HOSF
SFO
LO
FB
OB
NF
RMSEB
2.94 1.04 101.4 2.83ab
2.89 1.03 101.0 2.85ab
2.86 1.01 100.2 2.84ab
2.90 0.96 98.4 3.02ab
3.06 1.10 103.6 2.79b
2.84 0.93 97.3 3.05ab
3.01 0.95 98.0 3.21a
0.283 0.133 5.08 0.301
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B RMSE: Root Mean Square Error. A
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C.E. Realini et al. / Meat Science 85 (2010) 606–612 Table 4 Least-squares means for carcass parameters and primal cut yields of gilts fed experimental diets.A Carcass parameters
T
HOSF
SFO
LO
FB
OB
NF
RMSEB
Carcass weight (kg) Killing out (%) Flare fat (%) Last rib fat depth (mm) Fat depth 3–4 l.r.C Muscle depth 3–4 l.r.C Carcass lean (%)C
78.1 78.8ab 1.50b 13.5 15.1 51.0 56.3
79.0 78.4ab 1.84ab 15.7 17.9 49.8 53.6
76.6 79.3ab 1.83ab 15.9 17.9 49.7 53.6
75.0 78.5ab 1.62ab 14.3 16.3 50.8 55.3
79.4 78.2ab 1.62ab 14.0 16.1 51.7 55.6
73.7 77.5b 1.71ab 14.9 16.7 49.2 54.6
79.6 80.0a 1.95a 16.2 18.6 52.3 53.5
6.66 1.38 0.313 2.30 2.64 4.01 2.40
Primal cut yields (%) Ham Loin Shoulder Belly Tenderloin Other fat cutsD
24.50 18.29ab 13.86 9.08 1.22 7.92
24.38 17.69ab 13.70 9.84 1.22 8.48
24.17 18.42ab 13.54 9.88 1.22 8.19
24.67 17.94ab 13.54 9.50 1.25 7.98
24.65 17.23b 13.77 9.82 1.27 8.34
24.35 18.04ab 13.84 9.49 1.24 8.08
24.43 18.84a 13.40 9.69 1.21 7.70
0.802 0.931 0.529 0.694 0.098 0.599
a,b
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B RMSE: Root Mean Square Error. C Estimated with FOM., l.r.: last rib. D Other fat cuts: belly trimmings plus jowl. A
3.3. Dissection of major primal cuts Dissection yields of lean, subcutaneous fat, intermuscular fat, and bone from hams, loins and bellies are presented in Table 5. The percentage of lean, subcutaneous fat, intermuscular fat and fat:lean ratio from the ham did not differ (P > 0.05) among the dietary treatments. Moreover, percentages of bone and lean:bone ratios were not affected (P > 0.05) in any primal cut by dietary fat source. Lean percentage from the loin was greater (P < 0.05) for gilts fed T than NF, and, although there were no differences (P > 0.05) among treatments in percentage of subcutaneous fat from the loin, loins from NF-fed gilts had greater (P < 0.05) percentages of inter-
muscular fat than loins from gilts fed T, LO and FB. Percentages of separable fat (subcutaneous and intermuscular fat), as well as the fat:lean ratio, were higher (P < 0.05) for NF-fed than T-fed gilts. Duran-Montgé, Theil, Lauridsen, and Esteve-Garcia (2009a), Duran-Montgé, Theil, Lauridsen, and Esteve-Garcia (2009b) found highest mRNA abundances of genes encoding lipogenic enzymes and highest free and total triiodothyronine (T3) hormone contents in blood of pigs fed the NF diet and lowest values in pigs fed the T diet. In contrast to these results, Allee et al. (1972) reported that the dietary inclusion of 10% fat, regardless of source, produced more fat in the longissimus muscle than those fed the control diet devoid of added fat, whereas Kouba et al. (2003) found no effect of feeding 6% linseed on foreloin tissue composition in gilts.
Table 5 Least-squares means for ham, loin and belly dissection into lean, subcutaneous and intermuscular fat and bone of gilts fed experimental diets.A
a–c
Ham dissection (%)
T
HOSF
SFO
LO
FB
OB
NF
RMSEB
Lean Subcutaneous fatC Intermuscular fat Sub. + Inter. fat Fat:lean Bone Lean:bone
66.80 20.52 4.43 24.95 0.38 8.25 7.74
64.34 22.67 4.32 26.99 0.42 8.68 7.14
64.89 22.68 4.35 27.02 0.42 8.09 7.68
65.96 21.41 4.17 25.58 0.39 8.46 7.49
65.59 21.64 4.30 25.94 0.40 8.47 7.47
65.29 21.61 4.84 26.44 0.41 8.27 7.51
64.98 21.98 4.79 26.77 0.41 8.26 7.50
2.223 2.156 1.005 2.419 0.050 0.596 0.580
Loin dissection (%) Lean Subcutaneous fatC Intermuscular fat Sub. + Inter. fat Fat:lean Bone Lean:bone
54.67b 29.73 4.54b 34.28b 0.63b 11.05 4.58
51.45ab 31.98 5.69ab 37.67ab 0.75ab 10.88 4.32
50.99ab 32.84 5.58ab 38.42ab 0.76ab 10.59 4.38
54.13ab 30.05 4.91b 34.95ab 0.66ab 10.92 4.56
53.77ab 29.82 4.96b 34.78ab 0.65ab 11.45 4.19
51.89ab 31.36 5.34ab 36.69ab 0.71ab 11.41 4.16
49.95a 32.63 6.78a 39.41a 0.80a 10.65 4.41
3.108 3.393 1.177 3.485 0.105 1.008 0.442
Belly dissection (%) Lean Subcutaneous fatC Intermuscular fat Sub. + Inter. fat Fat:lean Bone Lean:bone
48.96ab 25.74ab 17.16b 42.90b 0.88bc 8.14 5.70
44.88bc 27.94a 19.33b 47.26ab 1.08ab 7.86 5.44
47.21ab 26.42ab 18.27b 44.68b 0.95bc 8.10 5.67
49.28a 24.48b 18.21b 42.69b 0.87c 8.03 5.78
48.32ab 25.45ab 18.47b 43.92b 0.92bc 7.76 5.88
47.86ab 24.86ab 19.14b 44.01b 0.93bc 8.13 5.58
41.70c 26.45ab 24.25a 50.71a 1.24a 7.59 5.11
2.943 2.281 2.664 3.300 0.141 1.050 0.708
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B RMSE: Root Mean Square Error. C Includes skin. A
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Lean percentages from the belly were lower for NF-fed gilts when compared with bellies from gilts fed LO, T, SFO, FB, and OB, and the belly lean percentage of LO-fed gilts was greater (P < 0.05) than that from HOSF- and NF-fed gilts. The percentage of subcutaneous fat from the bellies of gilts fed HOSF was greater (P < 0.05) than bellies of gilts fed LO, whereas the percentages of intermuscular fat and separable fat were greater in bellies from NF-fed gilts than all other dietary treatments. Fat:lean ratio for bellies from NF-fed gilts was greater (P < 0.05) than all added fat treatments except HOSF, and bellies from gilts fed HOSF had higher (P < 0.05) fat:lean ratios than bellies from gilts fed LO. Apple et al. (2009) reported no effect of dietary fat source on pork primal cut yields or dissected muscle, fat, bone and skin yields from each primal cut. Dugan, Aalhus, Robertson, Rolland, and Larsen (2004) found no differences in body cavity fat or intermuscular fat due to fat/oil type (canola oil vs. tallow) or level (2% vs. 5%). It has been shown in other species that the distribution of dietary fat within adipose tissues depends on the fatty acid profile. Sanz et al. (1999) fed broilers 10% T or SFO and found feeding SFO reduced abdominal fat pad. Crespo and Esteve-Garcia (2002a, 2002b) also reported that broilers fed LO had less abdominal fat than those fed T, indicating that high PUFA reduced fat deposition in separable fat depots with respect to MUFA and SFA. In contrast, results from the dissection of primal cuts in the present study do not appear to support the same pattern of fat deposition and distribution according to dietary FA profile reported in broilers. For example, the T-supplemented diet had the greatest content of SFA, but the percentage of dissected lean was the highest, while the percentage of separable fat was the least, in carcasses of gilts fed the T diet. In addition, it has been shown that T can lower
the expression of lipogenic enzymes in adipose tissue and reduce triiodothyronine (T3) hormone contents in blood (Duran-Montgé et al., 2009a, 2009b). 3.4. Ground carcass composition and fatty acid profile Moisture and ash content of carcass samples did not differ (P > 0.05) among dietary treatments (Table 6). However, carcasses from gilts fed SFO had a 4.3 greater (P < 0.05) percentage of fat and a 1.2 lower (P < 0.05) percentage of protein than carcasses of gilts fed T. Data on FA composition have focused on specific tissues of pigs, and there is limited information available on the FA composition of the whole carcass (Apple et al., 2009; Flanzy et al., 1970; Lizardo et al., 2002; Metz & Dekker, 1981; Mitchaotai et al., 2007). Gilts fed the NF diet had the greatest (P < 0.05) proportions of all SFA, whereas carcasses from gilts fed T had greater (P < 0.05) percentages of myristic (C14:0) and plamitic (C16:0) acids when compared with carcasses from gilts fed the other fat sources. In contrast, carcasses from gilts fed HOSF, SFO and LO had the lowest (P < 0.05) proportions of all SFA, especially C16:0. Shackelford, Miller, Haydon, and Reagan (1990) reported that whole carcass sausage from pigs fed finishing diets with no added fat had greater percentages of the SFA (C14:0, C16:0, and C18:0) than sausages manufactured from the lean and fat of pigs fed diets with 10% animal fat, safflower oil, SFO, or canola oil. Apple et al. (2009) also reported greater proportions of all SFA in carcass composite samples from pigs (slaughtered at 113.6 kg) fed a control diet with no added fat compared with diets including 5% added fat (beef tallow, poultry fat and soybean oil).
Table 6 Least-squares means for ground carcass composition and fatty acid profile of swine carcasses from gilts fed experimental diets.A T Ground carcass composition (%) Moisture 53.8 Fat 24.9b Protein 17.9b Ash 3.37 Carcass fatty acid profile (%) C 14:0 1.41a C 16:0 21.7b C 16:1 2.36a C 18:0 11.7b C 18:1 trans 0.28a C18:1 47.2b C 18:2, n 6 10.5d C 18:3, n 3 0.93d C 20:0 0.17cd C 20:1 0.88b C 20:2, n 6 0.53d C 20:3, n 6 0.12b C 20:4, n 6 0.44c C 20:3, n 3 0.16d C 20:5, n 3 EPA 0.032d C 22:4, n 6 0.11c C 22:5, n 3 DPA 0.21d C 22:6, n 3 DHA 0.11c SFAB 35.7b 50.9b MUFAB PUFAB 13.5d PUFA/SFA 0.38e n 6 12.2d n 3 1.43d n 6/n 3 ratio 8.45d a–f
HOSF
SFO
52.7 27.1ab 17.2ab 3.04
51.1 29.2a 16.7a 3.07
1.10cd 18.4e 1.54d 9.33d 0.13cd 54.1a 11.6c 0.72e 0.16d 1.00a 0.57cd 0.11c 0.49b 0.11d ND 0.13b 0.14ef 0.11bc 29.3d 56.7a 14.0d 0.49d 13.0cd 1.08e 11.9b
1.02e 17.9e 1.32e 10.8cd 0.12d 36.6d 27.5a 0.70ef 0.18bc 0.74c 1.31a 0.16a 0.55a 0.11d ND 0.16a 0.17e 0.15b 30.3d 38.8de 30.8a 1.03a 30.0a 1.12e 26.6a
LO
FB
OB
53.0 26.1ab 17.7ab 3.28
53.8 25.7ab 17.4ab 3.14
52.2 26.7ab 17.5ab 3.49
1.02de 18.1e 1.43de 11.2bc 0.12d 35.7d 13.3b 14.18a 0.18bc 0.66d 0.63b 0.085d 0.33d 1.60a 0.269b 0.074f 0.43b 0.10c 31.0d 37.9e 31.1a 1.01a 14.7b 16.6a 0.87f
1.27b 20.9c 1.94b 11.8b 0.19b 41.2c 12.9b 5.42c 0.18bc 0.79c 0.61bc 0.098c 0.34d 0.67c 0.125c 0.088e 0.36c 0.14bc 34.7b 44.2c 20.9c 0.61c 14.45b 6.72c 2.11e
1.16c 19.2d 1.73c 11.5b 0.13d 36.5d 11.7c 8.86b 0.19b 0.87b 0.58bcd 0.10c 0.47bc 0.92b 0.928ª 0.10d 1.02a 3.11a 32.8c 39.3d 27.9b 0.85b 13.2c 14.8b 0.88f
NF
SE
52.3 27.0ab 17.4ab 3.38
2.14 2.65 0.85 0.379
1.27b 24.4a 2.35a 14.1a 0.16c 47.5b 6.62e 0.47f 0.23a 0.98a 0.43e 0.076e 0.35d 0.10d ND 0.10d 0.12f 0.057d 40.6a 51.0b 8.32e 0.20f 7.53e 0.73f 10.2c
0.027 0.26 0.065 0.23 0.008 0.37 0.35 *
0.006 0.021 0.020 0.003 0.015 0.029 *
0.004 0.014 *
0.37 0.46 0.45 0.019 0.44 * *
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B SFA = saturated fatty acids; MUFA = monounsaturated fatty acids; and PUFA = polyunsaturated fatty acids.ND: under detection limit. * SE was not calculated as comparisons were done on arcsine values because of the great difference that existed between treatments. A
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The sum of all MUFA, and particularly oleic (C18:1) and gadoleic (C20:1) acids, was highest (P < 0.05) in carcasses from HOSF-fed gilts, but palmitoleic acid (C16:1) was greatest (P < 0.05) in carcasses of gilts fed T and NF (Table 6). On the other hand, carcasses from gilts fed LO had the lowest (P < 0.05) percentage of all MUFA, whereas the proportion of C16:1 was lowest in SFO-fed gilt carcasses (P < 0.05) and the proportion of C18:1 was least in carcasses from gilts fed SFO, LO, and OB. Apple et al. (2009) also demonstrated that diets with no added fat and those formulated with 5% of beef tallow had greater MUFA percentages than a soybean oil diet with a lower degree of saturation. Carcasses from gilts fed SFO and LO had the greatest (P < 0.05) proportion of all PUFA (Table 6). More specifically, carcasses from SFO-fed gilts had the greatest (P < 0.05) proportion of n 6 PUFA, including linoleic (C18:2, n 6), eicosadienoic (C20:2, n 6), dihomo-c-linolenic (C20:3, n 6), arachidonic (20:4, n 6), and docosatetraenoic (22:4, n 6) acids, whereas carcasses of LO-fed gilts had the greatest (P < 0.05) percentages of all n 3 PUFA, in particular linolenic (C18:3, n 3) and eicosatrienoic (C20:3, n 3) acids. Enser et al. (2000) demonstrated that feeding linseed high in C18:3 (4.0 g/kg) increased DHA levels 50% in adipose tissue, 43% in liver and 35% in muscle when compared with a control diet with only 1.9 g/kg C18:3. However, Riley et al. (1998a), Riley et al. (1998b), Ahn, Lutz, and Sim (1996), and Specht-Overholt et al. (1997) failed to observe an increase in DHA by feeding larger amounts of linseed that were fed in the Enser et al. (2000) study. These authors proposed that much higher tissue concentrations of linolenic (C18:3) and EPA may result in competitive exclusion of DHA from tissue lipids, particularly from phospholipids. In this trial, levels of 18:3 were 18.9, 31.2 and 47.1 g/kg feed for the FB, OB and LO diets, respectively, indicating potential exclusion of DHA from phospholipid synthesis. Carcasses from gilts fed NF had the lowest (P < 0.05) percentages of all PUFA, and feeding gilts T produced carcasses with lower (P < 0.05) C18:2 and C18:3 percentages than the other fat sources. Other authors have also shown that proportions of PUFA are similar in carcass composite samples (Apple et al., 2009), backfat (Wiseman, Redshaw, Jagger, Nute, & Wood, 2000) and pork (Brooks, 1971) between pigs fed diets with no added fat and diets formulated with beef tallow. Nutritional recommendations for a healthy diet suggest that the ratio of PUFA-to-SFA (PUFA/SFA) should be 0.40, or higher, and intakes of n 3 PUFA should be increased relative to n 6 PUFA. A value of 4.0 or less for the diet as a whole is recommended for the n 6/n 3 ratio (Department of Health, 1994). Pork is characterized by a high content of C18:2, which leads to acceptable PUFA/SFA ratios, but the high content in n 6 FA usually results in unfavorable n 6/n 3 FA ratios from a human health perspective. The PUFA/SFA ratio was greatest (P < 0.05) in carcasses from gilts fed SFO and LO, whereas carcasses from NF-fed gilts produced the lowest PUFA/SFA ratio (Table 6). Furthermore, n 6/n 3 fatty acid ratio was excessively high in carcasses from SFO-fed gilts, and carcasses from gilts fed OB, LO and FB had n 6/n 3 FA ratios below the recommended 4.0 for a healthy human diet. Although an increase in the n 3 FA concentration is desirable from a human health standpoint, oxidative stability in meat is reduced. Altering the PUFA content in pork may have important implications for meat quality, such as pork firmness (Apple et al., 2007), shelf-life (Morel, McIntosh, & Janz, 2006) and flavor characteristics of meat (Wiseman et al., 2000) due to their greater susceptibility to oxidation and the production of volatile compounds during cooking. Warnants, Van Oeckel, and Boucqué (1996) proposed thresholds for PUFA in feed of 18 g/kg feed and for PUFA in backfat of 22%, whereas Bryhni, Kjos, Ofstad, and Hunt (2002) proposed less than 50 g PUFA/kg feed and 23% PUFA in backfat to help reduce oxidation problems indicating lower values for processed pork products. In this trial PUFA values in feed were 1.6,
611
16.1, 22.8, 74.5, 73.4, 45.2, and 70.8 g/kg and percentages of PUFA in carcasses were 8.3%, 13.5%, 14.0%, 30.8%, 31.1%, 20.9%, and 27.9% for NF, T, HOSF, SFO, LO, FB, and OB, respectively, indicating that high levels of fat addition, specifically SFO, LO and OB, may compromise sensory and technological quality of pork and pork products. 4. Conclusions Although the FA composition of the diet has major effects on carcass fatty acid composition, source of dietary fat in this study had only minimal effects on animal performance, carcass characteristics, and carcass fat content and distribution. Diets rich in PUFA did not reduce fat deposition in separable fat depots with respect to MUFA and SFA as previously shown in other species. Feeding a diet with no added fat may result in carcasses and primal cuts with a higher fat content compared with diets formulated with high levels of fat. As expected, carcass fatty acid composition reflected the fatty acid composition of the fat sources used in this experiment. Carcasses from gilts fed T had a high degree of saturation, with a FA composition similar to carcasses from NF-fed gilts. Carcasses from gilts fed FB and OB showed intermediate percentages in most fatty acids with higher n 3 fatty acids for OB than FB. Gilts fed HOSF resulted in carcasses with high percentage of MUFA, while carcasses from gilts fed SFO and LO showed high percentages of n 6 and n 3 FA, respectively. PUFA/SFA ratios were substantially increased by feeding gilts SFO, LO, OB, FB and HOSF, whereas carcasses from gilts fed FB, OB, LO had n 6/n 3 ratios within the recommended levels from a nutritional point of view. Ten percent addition o fat and particularly SFO, LO and OB may compromise technological and sensory quality of pork and pork products. Combinations of different fat sources (FB) and lower levels of fat addition may result in carcass fatty acid profiles with nutritional benefits without compromising pork quality. Acknowledgements This research was funded by the Spanish National Institute of Agricultural Research (INIA) corresponding to Project No. RTA03060-C2-1. References Ahn, D. H., Lutz, S., & Sim, J. S. (1996). Effects of dietary a-linolenic acid on the fatty acid composition, storage stability and sensory characteristics of pork loin. Meat Science, 43, 291–299. Allee, G. L., Romsos, D. R., Leveille, G. A., & Baker, D. H. (1972). Lipongenesis and enzymatic activity in pig adipose tissue as influenced by source of dietary fat. Journal of Animal Science, 35, 41–47. AOAC (1990). Official methods of analysis (15th ed.). Washington, DC: Association of Official Analytical Chemists. AOAC (2000). Official methods of analysis (16th ed.). Washington, DC: Association of Official Analytical Chemists. Apple, J. K., Maxwell, C. V., Galloway, D. L., Hamilton, C. R., & Yancey, J. W. S. (2009). Interactive effects of dietary fat source and slaughter weight in growingfinishing swine: III. Carcass and fatty acid compositions. Journal of Animal Science, 87, 1441–1454. Apple, J. K., Maxwell, C. V., Sawyer, J. T., Kutz, B. R., Rakes, L. K., Davis, M. E., et al. (2007). Interactive effect of ractopamine and dietary fat source on quality characteristics of fresh pork bellies. Journal of Animal Science, 85, 2682–2690. Bee, G., Gebert, S., & Messikommer, R. (2002). Effect of dietary energy supply and fat source on the fatty acid pattern of adipose and lean tissues and lipogenesis in the pig. Journal of Animal Science, 80, 1564–1574. Brooks, C. C. (1971). Fatty acid composition of pork lipids as affected by basal diet, fat source and fat level. Journal of Animal Science, 33, 1224–1231. Bryhni, E. A., Kjos, N. P., Ofstad, R., & Hunt, M. (2002). Polyunsaturated fat and fish oil in diets for growing-finishing pigs: Effects on fatty acid composition and meat, fat, and sausage quality. Meat Science, 62, 1–8. Crespo, N., & Esteve-Garcia, E. (2001). Dietary fatty acid profile modifies abdominal fat deposition in broiler chickens. Poultry Science, 80, 71–78. Crespo, N., & Esteve-Garcia, E. (2002a). Dietary polyunsaturated fatty acids decrease fat deposition in separable fat depots but not in the remainder carcass. Poultry Science, 81, 512–518.
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Effect of source of dietary fat on pig performance, carcass characteristics and carcass fat content, distribution and fatty acid composition C.E. Realini a,*, P. Duran-Montgé b, R. Lizardo c, M. Gispert a, M.A. Oliver a, E. Esteve-Garcia c a
IRTA, Monells, Building B–Finca Camps i Armet E-17121 Monells (Girona), Spain CENTA, IRTA Building A–Finca Camps i Armet E-17121 Monells (Girona), Spain c IRTA, Mas de Bover, Ctra. Reus-El Morell Km. 3,8 E-43120 Constantí (Tarragona), Spain b
a r t i c l e
i n f o
Article history: Received 17 June 2009 Received in revised form 18 September 2009 Accepted 11 March 2010
Keywords: Dietary fat Swine Carcass Fatty acids
a b s t r a c t Seventy gilts were used to compare the effect of including 10% tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), a fat blend (FB), or an oil blend (OB) in finishing diets vs. feeding a semi-synthetic diet with no added fat (NF) on pig performance, carcass traits and carcass fatty acid (FA) composition. Carcasses from SFO-fed gilts had greater fat and lower lean compositions than carcasses from T-fed gilts. Gilts fed NF had greater loin fat than FB-fed gilts, and greater flare fat, loin intermuscular fat and fat:lean than T-fed gilts. Bellies from NF-fed gilts had lower lean and higher intermuscular fat and fat:lean than other diets except HOSF. Fat source had minor effects on animal performance, carcass characteristics and carcass fat content and distribution, whereas feeding NF resulted in carcasses and major cuts with higher fat content. Diets rich in polyunsaturated FA (PUFA) did not reduce fat deposition in separable fat depots with respect to monounsaturated FA (MUFA) and saturated FA (SFA). Carcasses from gilts fed NF had a high degree of saturation (40.6% SFA) followed by carcasses of T- and FB-fed gilts. Feeding HOSF, SFO and LO enriched diets elevated the percentages of MUFA (56.7%), n 6 (30.0%) and n 3 (16.6%) PUFA, respectively, whereas carcasses from gilts fed OB had greater percentages of n 3 FA (14.8% n 3, 0.9% EPA, 1.0% DPA, 3.1% DHA) than gilts fed FB (6.72% n 3, 0.1% EPA, 0.4% DPA, 0.1% DHA). Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction The pork industry has made significant efforts to decrease the total amount of fat deposited in pigs through genetics, management and nutrition. At the same time extensive research has been dedicated towards changing the fatty acid composition of pork products to better match processing requirements and dietary recommendations for the human diet. It is generally accepted that fatty acid (FA) composition of porcine adipose tissue is dependent upon the fatty acid profile of the diet (Bee, Gebert, & Messikommer, 2002; Kouba, Enser, Whittington, Nute, & Wood, 2003; Miller, Shackelford, Hayden, & Reagan, 1990; Mitchaotai et al., 2007; Nuernberg et al., 2005). It has also been shown in broilers that diets rich in polyunsaturated fatty acids (PUFA) reduced abdominal fat deposition compared with feeding diets with predominantly saturated or monounsaturated fats (Crespo & EsteveGarcia, 2001, 2002a; Sanz, Flores, Pérez de Ayala, & López-Bote, 1999). Conversely, a majority of the previous research has failed to demonstrate an effect of feeding swine finishing diets formu-
* Corresponding author. Tel.: +34 972 630052; fax: +34 972 630373. E-mail address: [email protected] (C.E. Realini). 0309-1740/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2010.03.011
lated with beef tallow, poultry fat, soybean oil, linseed oil, and sunflower oil on primal cut yields or carcass composition (Apple, Maxwell, Galloway, Hamilton, & Yancey, 2009; Eggert, Grant, & Schinckel, 2007; Enser, Richardson, Wood, Gill, & Sheard, 2000); however, there are a number of other fat sources and combinations of fat sources which may affect swine carcass composition and/or fat distribution. Most fatty acid research has been conducted in individual adipose tissues (subcutaneous, intermuscular and retroperitoneal) and intramuscular fat from different muscles (Longissimus dorsi, Semimembranosus, Biceps femoris, Diaphragama, Masseter), with limited information on the fatty acid composition of the whole carcass (Apple et al., 2009; Flanzy, François, & Rérat, 1970; Lizardo, van Milgen, Mourot, Noblet, & Bonneau, 2002; Metz & Dekker, 1981; Mitchaotai et al., 2007). Therefore, the objectives of this study were to determine the effect of adding approximately 10% of different dietary fat sources (beef tallow, high-oleic sunflower oil, sunflower oil, and linseed oil) and combinations of fat sources (a fat blend of tallow, sunflower oil and linseed oil or an oil blend of fish and linseed oils) compared with a diet with no added fat on pig performance, carcass characteristics, carcass composition and fat distribution, as well as carcass fatty acid composition, of crossbred gilts.
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C.E. Realini et al. / Meat Science 85 (2010) 606–612 Table 2 Fatty acid (FA) content of experimental diets.a
2. Materials and methods 2.1. Animals and diets
Fatty acid (g/kg feed)
T
HOSF
SFO
LO
FB
OB
NF
Experimental procedures were approved by IRTA’s ethical committee. Duroc Landrace gilts were fed a barley-corn-soybean meal-based diet during a pre-experimental period. Seventy gilts (61.8 ± 5.2 kg live weight), divided in two periods, were grouped by blocks based on live weight, and randomly assigned within blocks to one of seven dietary treatments (10 gilts/treatment). Six fat supplemented diets based on barley and soybean were formulated to meet or exceed nutrient requirements for finishing pigs (NRC, 1998). Additionally, a semi-synthetic diet was formulated using purified ingredients and contained no fat (Table 1). Fat supplementation (10% fat) was determined in order to supply an equal amount of digestible fat based on results from previous trials (Duran-Montgé, Lizardo, Torrallardona, & Esteve-Garcia, 2007). Four fat sources and two combinations of fat sources were selected in order to achieve diets with different fatty acid composition (Table 2). Thus, beef tallow (T) was included to have a diet rich in saturated fatty acids (SFA), whereas high-oleic acid sunflower oil (HOSF), sunflower oil (SFO), and linseed oil (LO) were selected to have diets rich in oleic, linoleic and linolenic acids, respectively. The diet formulated with the fat blend (FB: 55% T, 35% SFO and 15% LO) had intermediate levels of the most prominent FA (palmitic, stearic, oleic, linoleic and linolenic acids), and the diet formulated with the oil blend (OB: 40% fish oil and 60% LO) was formulated to contain a high amount of long-chain PUFA because of the elevated levels of these fatty acids in fish oil. Gilts were individually penned and had ad libitum access to their dietary treatment and water during 50 days. Live weight and feed intake were recorded at the
C14:0 C16:0 C16:1 C18:0 C18:1trans C18:1 C18:2, n 6 C18:3, n 3 C20:0 C22:0 C20:5, n 3 EPA C22:6, n 3 DHA C24:0 Sum FA SFAb MUFAb PUFAb PUFA/SFA n 6 n 3 n 6/n 3
3.34 28.7 2.37 22.9 0.23 34.8 14.2 1.90 0.13 0.07 ND ND 0.03 116.8 57.2 36.2 16.1 0.3 14.2 1.9 7.5
0.12 7.87 0.19 4.25 0.10 86.8 21.5 1.29 0.40 1.15 ND ND 0.42 125.6 14.3 87.4 22.8 1.6 21.5 1.3 16.5
0.13 11.2 0.11 5.56 0.27 32.5 73.3 1.26 0.43 1.02 ND ND 0.31 128.0 18.8 33.2 74.5 4.0 73.3 1.3 56.4
0.09 8.21 0.08 3.64 0.06 20.7 26.2 47.1 0.19 0.20 ND ND 0.15 108.1 12.6 21.1 73.4 5.8 26.2 47.2 0.60
1.72 20.0 1.35 12.8 0.27 29.5 26.0 18.9 0.24 0.23 0.02 0.04 0.05 115.4 36.0 30.5 45.2 1.3 26.1 19.0 1.4
1.53 13.0 1.81 4.07 0.10 19.0 21.5 31.2 0.26 0.24 3.88 12.3 0.13 114.7 20.0 20.5 70.8 3.5 22.5 48.3 0.5
ND 0.48 ND 0.14 0.04 0.56 1.38 0.18 0.01 0.01 ND ND ND 4.0 0.6 0.7 1.6 2.7 1.4 0.2 7.0
a T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. b SFA = saturated fatty acids; MUFA = monounsaturated fatty acids; and PUFA = polyunsaturated fatty acids. ND: under detection limit.
beginning of the trial and again three weeks later, as well as at the end of the trail. 2.2. Dietary chemical composition, fat content and fatty acid profile
Table 1 Ingredient and chemical composition of experimental diets.a Ingredient (%)
T
Wheat starch Soybean protein concentrate Sugar beet pulp Molasses Barley Soybean meal 44% Tallowb High-oleic sunflower oilb Sunflower oilb Linseed oilb Fish oilb Calcium carbonate Mineral/vitamin complexc Dicalcium phosphate Sodium chloride L-Lysine
HCl
HOSF
SFO
LO
FB
OB
70.0 14.0 10.1 4.00 62.4 24.1 11.0
63.8 24.1
63.4 24.1
63.7 24.1
63.5 24.1 5.5
63.4 24.1
9.6 10.0
1.61 0.40 0.27 0.22 0.02
1.61 0.40 0.27 0.22 0.02
1.61 0.40 0.27 0.22 0.02
9.7
3.5 1.0
1.61 0.40 0.27 0.22 0.02
1.61 0.40 0.27 0.22 0.02
5.8 3.9 1.61 0.40 0.27 0.22 0.02
1.08 0.40 0.20 0.15 0.04
DL-Methionine
Chemical composition Net energy (M cal kg Crude protein (%) Total lysine (%) Crude fat (%) Ash (%)
NF
Dietary dry matter content, ash, crude fat, and energy were determined according to AOAC (1990), and crude protein was determined following the Dumas method (method No. 968.06; AOAC, 2000) using a nitrogen/protein analyzer (model FP528; Leco, St. Joseph, MI, USA). Feed lipids were extracted following the procedure of Folch, Lees, and Stanley (1957), converted to fatty acid methyl esters using BF3 and methanolic KOH (Morrison & Smith, 1964) and analyzed using GC (model HP-6890; Hewlett–Packard, Avondale, PA, USA) equipped with an automatic injector, using C19:0 as internal standard. Aliquots of 1 ll were injected into a capillary column (30 m 0.25 mm 0.25 lm DB-23 p/n 1222332; Agilent) with cyanopropyl methyl silicone as stationary phase. Column oven temperature was programmed at 170– 210 °C at 2.5 °C/min, 210–240 °C at 5 °C/min, and held at 240 °C for 5 min with 1:100 split. Injector and detector temperatures were maintained at 250 °C. Hydrogen was the carrier gas at a flow rate of 0.5 mL/min. 2.3. Carcass measurements
1
)
2.61 15.6 0.88 12.7 5.03
2.63 15.1 0.88 11.5 4.83
2.65 15.5 0.88 13.4 4.82
2.61 15.9 0.88 11.6 5.09
2.63 15.8 0.88 11.6 5.11
2.60 16.1 0.88 11.5 5.16
2.22 14.1 0.81 0.32 2.93
a T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. b Fat supplemented diets were formulated in order to supply an equal amount of digestible fat based on previous measurements (Duran-Montgé et al., 2007). C About 5000 IU of vitamin A, 1000 IU vitamin D3, 15 mg vitamin E, 1.3 mg vitamin B1, 3.5 mg vitamin B2, 0.025 mg vitamin B12, 1.5 mg vitamin B6, 10 mg calcium pantothenate, 15 mg nicotinic acid, 0.1 mg folic acid, 2 mg vitamin K3, 80 mg Fe, 6 mg Cu, 0.75 mg Co, 60 mg Zn, 30 mg Mn, 0.75 mg I, 0.10 mg Se, and 0.15 ethoxiquin were provided/kg of feed.
Pigs were transported to the slaughter facilities of IRTA-Monells approximately 14 h before slaughter and were held off feed, but not water, during lairage. Gilts (99.8 ± 8.5 kg live weight) were humanely harvested using CO2 stunning following standard procedures of an officially inspected facility. Carcass and flare fat weights and fat and muscle depths were recorded for each carcass within 1 h postmortem using the Fat-O-Meat’er probe (SFK Technology, Denmark). Muscle and fat depths were measured both at the last rib level and between the 3rd and 4th thoracic ribs counting from the last one (60 mm from the mid-line), and percent carcass lean was predicted using the official Spanish equation of Gispert and Diestre (1994). Then, left sides were commercially
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cut and all primal cuts (ham, loin, shoulder, belly, and tenderloin), as well as other fat cuts (including the jowl and belly trimmings), were weighed to obtain cut yields. In addition, hams, loins and bellies were dissected into lean, subcutaneous and intermuscular fat, and bone following the procedure of Walstra and Merkus (1995). The right side of each carcass was reduced into small pieces using a cutting guillotine (Model D, Olot, Spain) and stored frozen at 20 °C before grinding three times through five eyes, 8 mm and 3 mm plates attached to an industrial grinder with 160 mm head (Grinder Cato-PA160, Sabadell, Spain). The ground side was then thoroughly homogenized for 1 min using a mixer before 500-g samples were collected for proximate and fatty acid composition analyses.
ditions. Allee, Romsos, Leveille, and Baker (1972) found that addition of 10% fat to a low-fat diet, regardless of the source, resulted in an increase in daily gain and gain:feed ratio. Dugan, Aalhus, Lien, Schaefer, and Kramer (2001) reported leaner carcasses as a consequence of improved feed efficiency, more lean and less subcutaneous fat in primal cuts of barrows fed 5% vs. 2% canola oil, but no differences in feed efficiency between treatments were noted in gilts. However, a number of researchers have failed to observe an effect of dietary fat sources on growth performance (Bee et al., 2002; Rossi & Corino, 2002). Mitchaotai et al. (2007) reported no difference in daily gain, daily feed intake, feed conversion efficiency, or final body weight between pigs fed 5% T or 5% SFO, whereas Guillevic, Kouba, and Mourot (2009) noted that neither LO nor SFO impacted growth rate or feed intake.
2.4. Ground carcass composition and fatty acid profile Ground carcass samples were analyzed for crude protein as previously described for feed samples, moisture content was determined by freeze-drying in a Liodelta Telstar (Terrassa, Spain) freeze-dryer for 48 h, and ash content was determined by ashing samples in a muffle oven at 525 °C for 3 h (method 923.03; AOAC, 1990). Lipid from ground carcass was determined following the chloroform–methanol procedure of Folch et al. (1957). Extracted lipids were converted to fatty acid methyl esters using BF3 and methanolic KOH (Morrison & Smith, 1964), and analyzed by GC (model HP-6890; Hewlett–Packard, Avondale, PA, USA) using the same conditions described for feed lipid analysis. 2.5. Statistical analysis Data were analyzed using the GLM procedure of SAS (SAS Inst. Inc., Cary, NC) including dietary treatment and period in the model. Live and carcass weights were included in the model as covariates for live animal and carcass data analyses, respectively. The covariate carcass weight was significant (P < 0.05) for most carcass variables except for those expressed as a percentage of the carcass (primal cut yields). Differences in least-squares means among dietary treatments were assessed by the Tukey–Kramer test, with significance determined at P < 0.05. 3. Results and discussion 3.1. Animal performance There were no differences (P > 0.05) among dietary treatments for average daily feed intake, average daily gain and final live weight of gilts (Table 3). Gilts fed FB had an improved (P < 0.05) feed:gain ratio over gilts fed NF (0.42 kg feed kg 1gain) with other dietary treatments being intermediate. The addition of fat/oil in the diet has previously been found to improve feed efficiency (Pettigrew & Moser, 1991; Smith, Tokach, O’Quinn, Nelssen, & Goodband, 1999). De la Llata et al. (2001) indicated that adding 6% fat to corn-soybean meal diets consistently improved feed efficiency of barrows and gilts in all phases of growth under commercial con-
3.2. Carcass characteristics and primal cut yields Carcass characteristics and primal cut yields of gilts fed the different experimental diets are shown in Table 4. Killing out percentage was greater (P < 0.05) for gilts fed NF than gilts fed OB, but there were no differences (P > 0.05) among gilts fed T, HOSF, SFO, LO and FB. In addition, flare fat percentage was greater (P < 0.05) in carcasses of NF-fed gilts than carcasses of T-fed gilts; otherwise, carcass weight, fat depths measured at the last rib and between the 3rd and 4th last ribs, muscle depth measured between the 3rd and 4th last ribs, and estimated lean percentage did not differ (P > 0.05) among dietary fat sources. With the exception that loin yields from gilts fed NF were greater (P < 0.05) than those from gilts fed FB, the percentages of ham, shoulder, belly, tenderloin, and other fat cuts were similar (P > 0.05) among the dietary treatments. These results contradict those of Pettigrew and Moser (1991) and Miller et al. (1990), who reported that adding fat in diets of growing-finishing pigs increased carcass fatness. Moreover, Stahly and Cromwell (1979) and Stahly, Cromwell, and Overfield (1981) observed that backfat depths and carcass fat percentages were increased in pigs fed 5% T, whereas Allee et al. (1972) noted that the addition of 10% corn oil, lard, coconut oil or T not only increased backfat thickness, perirenal fat, and fat trim, but also reduced longissimus muscle area and carcass lean composition when compared to a control diet devoid of fat. On the other hand, results of the present experiment concur with a number of previous studies where dietary fat source did not impact pork carcass traits (De la Llata et al., 2001; Mitchaotai et al., 2007). Nuernberg et al. (2005) fed diets composed of 5% LO or olive oil, and reported no differences in any carcass characteristics between fat sources. Moreover, Bee et al. (2002) fed diets formulated with 5% T or soybean oil, whereas Rossi and Corino (2002) fed diets 3% T, corn oil or rapeseed oil, and neither study demonstrated an effect of fat source on carcass characteristics or subprimal yields. Guillevic et al. (2009) also found no effect of LO or SFO on pork quality or subprimal weights, which is in agreement with results from the present study.
Table 3 Least-squares means for average daily feed intake (ADFI), average daily gain (ADG), final live weight (FLW), and feed:gain ratio of gilts fed experimental diets.A
ADFI (kg d 1) ADG (kg d 1) FLW (kg) Feed:gain a,b
T
HOSF
SFO
LO
FB
OB
NF
RMSEB
2.94 1.04 101.4 2.83ab
2.89 1.03 101.0 2.85ab
2.86 1.01 100.2 2.84ab
2.90 0.96 98.4 3.02ab
3.06 1.10 103.6 2.79b
2.84 0.93 97.3 3.05ab
3.01 0.95 98.0 3.21a
0.283 0.133 5.08 0.301
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B RMSE: Root Mean Square Error. A
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C.E. Realini et al. / Meat Science 85 (2010) 606–612 Table 4 Least-squares means for carcass parameters and primal cut yields of gilts fed experimental diets.A Carcass parameters
T
HOSF
SFO
LO
FB
OB
NF
RMSEB
Carcass weight (kg) Killing out (%) Flare fat (%) Last rib fat depth (mm) Fat depth 3–4 l.r.C Muscle depth 3–4 l.r.C Carcass lean (%)C
78.1 78.8ab 1.50b 13.5 15.1 51.0 56.3
79.0 78.4ab 1.84ab 15.7 17.9 49.8 53.6
76.6 79.3ab 1.83ab 15.9 17.9 49.7 53.6
75.0 78.5ab 1.62ab 14.3 16.3 50.8 55.3
79.4 78.2ab 1.62ab 14.0 16.1 51.7 55.6
73.7 77.5b 1.71ab 14.9 16.7 49.2 54.6
79.6 80.0a 1.95a 16.2 18.6 52.3 53.5
6.66 1.38 0.313 2.30 2.64 4.01 2.40
Primal cut yields (%) Ham Loin Shoulder Belly Tenderloin Other fat cutsD
24.50 18.29ab 13.86 9.08 1.22 7.92
24.38 17.69ab 13.70 9.84 1.22 8.48
24.17 18.42ab 13.54 9.88 1.22 8.19
24.67 17.94ab 13.54 9.50 1.25 7.98
24.65 17.23b 13.77 9.82 1.27 8.34
24.35 18.04ab 13.84 9.49 1.24 8.08
24.43 18.84a 13.40 9.69 1.21 7.70
0.802 0.931 0.529 0.694 0.098 0.599
a,b
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B RMSE: Root Mean Square Error. C Estimated with FOM., l.r.: last rib. D Other fat cuts: belly trimmings plus jowl. A
3.3. Dissection of major primal cuts Dissection yields of lean, subcutaneous fat, intermuscular fat, and bone from hams, loins and bellies are presented in Table 5. The percentage of lean, subcutaneous fat, intermuscular fat and fat:lean ratio from the ham did not differ (P > 0.05) among the dietary treatments. Moreover, percentages of bone and lean:bone ratios were not affected (P > 0.05) in any primal cut by dietary fat source. Lean percentage from the loin was greater (P < 0.05) for gilts fed T than NF, and, although there were no differences (P > 0.05) among treatments in percentage of subcutaneous fat from the loin, loins from NF-fed gilts had greater (P < 0.05) percentages of inter-
muscular fat than loins from gilts fed T, LO and FB. Percentages of separable fat (subcutaneous and intermuscular fat), as well as the fat:lean ratio, were higher (P < 0.05) for NF-fed than T-fed gilts. Duran-Montgé, Theil, Lauridsen, and Esteve-Garcia (2009a), Duran-Montgé, Theil, Lauridsen, and Esteve-Garcia (2009b) found highest mRNA abundances of genes encoding lipogenic enzymes and highest free and total triiodothyronine (T3) hormone contents in blood of pigs fed the NF diet and lowest values in pigs fed the T diet. In contrast to these results, Allee et al. (1972) reported that the dietary inclusion of 10% fat, regardless of source, produced more fat in the longissimus muscle than those fed the control diet devoid of added fat, whereas Kouba et al. (2003) found no effect of feeding 6% linseed on foreloin tissue composition in gilts.
Table 5 Least-squares means for ham, loin and belly dissection into lean, subcutaneous and intermuscular fat and bone of gilts fed experimental diets.A
a–c
Ham dissection (%)
T
HOSF
SFO
LO
FB
OB
NF
RMSEB
Lean Subcutaneous fatC Intermuscular fat Sub. + Inter. fat Fat:lean Bone Lean:bone
66.80 20.52 4.43 24.95 0.38 8.25 7.74
64.34 22.67 4.32 26.99 0.42 8.68 7.14
64.89 22.68 4.35 27.02 0.42 8.09 7.68
65.96 21.41 4.17 25.58 0.39 8.46 7.49
65.59 21.64 4.30 25.94 0.40 8.47 7.47
65.29 21.61 4.84 26.44 0.41 8.27 7.51
64.98 21.98 4.79 26.77 0.41 8.26 7.50
2.223 2.156 1.005 2.419 0.050 0.596 0.580
Loin dissection (%) Lean Subcutaneous fatC Intermuscular fat Sub. + Inter. fat Fat:lean Bone Lean:bone
54.67b 29.73 4.54b 34.28b 0.63b 11.05 4.58
51.45ab 31.98 5.69ab 37.67ab 0.75ab 10.88 4.32
50.99ab 32.84 5.58ab 38.42ab 0.76ab 10.59 4.38
54.13ab 30.05 4.91b 34.95ab 0.66ab 10.92 4.56
53.77ab 29.82 4.96b 34.78ab 0.65ab 11.45 4.19
51.89ab 31.36 5.34ab 36.69ab 0.71ab 11.41 4.16
49.95a 32.63 6.78a 39.41a 0.80a 10.65 4.41
3.108 3.393 1.177 3.485 0.105 1.008 0.442
Belly dissection (%) Lean Subcutaneous fatC Intermuscular fat Sub. + Inter. fat Fat:lean Bone Lean:bone
48.96ab 25.74ab 17.16b 42.90b 0.88bc 8.14 5.70
44.88bc 27.94a 19.33b 47.26ab 1.08ab 7.86 5.44
47.21ab 26.42ab 18.27b 44.68b 0.95bc 8.10 5.67
49.28a 24.48b 18.21b 42.69b 0.87c 8.03 5.78
48.32ab 25.45ab 18.47b 43.92b 0.92bc 7.76 5.88
47.86ab 24.86ab 19.14b 44.01b 0.93bc 8.13 5.58
41.70c 26.45ab 24.25a 50.71a 1.24a 7.59 5.11
2.943 2.281 2.664 3.300 0.141 1.050 0.708
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B RMSE: Root Mean Square Error. C Includes skin. A
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Lean percentages from the belly were lower for NF-fed gilts when compared with bellies from gilts fed LO, T, SFO, FB, and OB, and the belly lean percentage of LO-fed gilts was greater (P < 0.05) than that from HOSF- and NF-fed gilts. The percentage of subcutaneous fat from the bellies of gilts fed HOSF was greater (P < 0.05) than bellies of gilts fed LO, whereas the percentages of intermuscular fat and separable fat were greater in bellies from NF-fed gilts than all other dietary treatments. Fat:lean ratio for bellies from NF-fed gilts was greater (P < 0.05) than all added fat treatments except HOSF, and bellies from gilts fed HOSF had higher (P < 0.05) fat:lean ratios than bellies from gilts fed LO. Apple et al. (2009) reported no effect of dietary fat source on pork primal cut yields or dissected muscle, fat, bone and skin yields from each primal cut. Dugan, Aalhus, Robertson, Rolland, and Larsen (2004) found no differences in body cavity fat or intermuscular fat due to fat/oil type (canola oil vs. tallow) or level (2% vs. 5%). It has been shown in other species that the distribution of dietary fat within adipose tissues depends on the fatty acid profile. Sanz et al. (1999) fed broilers 10% T or SFO and found feeding SFO reduced abdominal fat pad. Crespo and Esteve-Garcia (2002a, 2002b) also reported that broilers fed LO had less abdominal fat than those fed T, indicating that high PUFA reduced fat deposition in separable fat depots with respect to MUFA and SFA. In contrast, results from the dissection of primal cuts in the present study do not appear to support the same pattern of fat deposition and distribution according to dietary FA profile reported in broilers. For example, the T-supplemented diet had the greatest content of SFA, but the percentage of dissected lean was the highest, while the percentage of separable fat was the least, in carcasses of gilts fed the T diet. In addition, it has been shown that T can lower
the expression of lipogenic enzymes in adipose tissue and reduce triiodothyronine (T3) hormone contents in blood (Duran-Montgé et al., 2009a, 2009b). 3.4. Ground carcass composition and fatty acid profile Moisture and ash content of carcass samples did not differ (P > 0.05) among dietary treatments (Table 6). However, carcasses from gilts fed SFO had a 4.3 greater (P < 0.05) percentage of fat and a 1.2 lower (P < 0.05) percentage of protein than carcasses of gilts fed T. Data on FA composition have focused on specific tissues of pigs, and there is limited information available on the FA composition of the whole carcass (Apple et al., 2009; Flanzy et al., 1970; Lizardo et al., 2002; Metz & Dekker, 1981; Mitchaotai et al., 2007). Gilts fed the NF diet had the greatest (P < 0.05) proportions of all SFA, whereas carcasses from gilts fed T had greater (P < 0.05) percentages of myristic (C14:0) and plamitic (C16:0) acids when compared with carcasses from gilts fed the other fat sources. In contrast, carcasses from gilts fed HOSF, SFO and LO had the lowest (P < 0.05) proportions of all SFA, especially C16:0. Shackelford, Miller, Haydon, and Reagan (1990) reported that whole carcass sausage from pigs fed finishing diets with no added fat had greater percentages of the SFA (C14:0, C16:0, and C18:0) than sausages manufactured from the lean and fat of pigs fed diets with 10% animal fat, safflower oil, SFO, or canola oil. Apple et al. (2009) also reported greater proportions of all SFA in carcass composite samples from pigs (slaughtered at 113.6 kg) fed a control diet with no added fat compared with diets including 5% added fat (beef tallow, poultry fat and soybean oil).
Table 6 Least-squares means for ground carcass composition and fatty acid profile of swine carcasses from gilts fed experimental diets.A T Ground carcass composition (%) Moisture 53.8 Fat 24.9b Protein 17.9b Ash 3.37 Carcass fatty acid profile (%) C 14:0 1.41a C 16:0 21.7b C 16:1 2.36a C 18:0 11.7b C 18:1 trans 0.28a C18:1 47.2b C 18:2, n 6 10.5d C 18:3, n 3 0.93d C 20:0 0.17cd C 20:1 0.88b C 20:2, n 6 0.53d C 20:3, n 6 0.12b C 20:4, n 6 0.44c C 20:3, n 3 0.16d C 20:5, n 3 EPA 0.032d C 22:4, n 6 0.11c C 22:5, n 3 DPA 0.21d C 22:6, n 3 DHA 0.11c SFAB 35.7b 50.9b MUFAB PUFAB 13.5d PUFA/SFA 0.38e n 6 12.2d n 3 1.43d n 6/n 3 ratio 8.45d a–f
HOSF
SFO
52.7 27.1ab 17.2ab 3.04
51.1 29.2a 16.7a 3.07
1.10cd 18.4e 1.54d 9.33d 0.13cd 54.1a 11.6c 0.72e 0.16d 1.00a 0.57cd 0.11c 0.49b 0.11d ND 0.13b 0.14ef 0.11bc 29.3d 56.7a 14.0d 0.49d 13.0cd 1.08e 11.9b
1.02e 17.9e 1.32e 10.8cd 0.12d 36.6d 27.5a 0.70ef 0.18bc 0.74c 1.31a 0.16a 0.55a 0.11d ND 0.16a 0.17e 0.15b 30.3d 38.8de 30.8a 1.03a 30.0a 1.12e 26.6a
LO
FB
OB
53.0 26.1ab 17.7ab 3.28
53.8 25.7ab 17.4ab 3.14
52.2 26.7ab 17.5ab 3.49
1.02de 18.1e 1.43de 11.2bc 0.12d 35.7d 13.3b 14.18a 0.18bc 0.66d 0.63b 0.085d 0.33d 1.60a 0.269b 0.074f 0.43b 0.10c 31.0d 37.9e 31.1a 1.01a 14.7b 16.6a 0.87f
1.27b 20.9c 1.94b 11.8b 0.19b 41.2c 12.9b 5.42c 0.18bc 0.79c 0.61bc 0.098c 0.34d 0.67c 0.125c 0.088e 0.36c 0.14bc 34.7b 44.2c 20.9c 0.61c 14.45b 6.72c 2.11e
1.16c 19.2d 1.73c 11.5b 0.13d 36.5d 11.7c 8.86b 0.19b 0.87b 0.58bcd 0.10c 0.47bc 0.92b 0.928ª 0.10d 1.02a 3.11a 32.8c 39.3d 27.9b 0.85b 13.2c 14.8b 0.88f
NF
SE
52.3 27.0ab 17.4ab 3.38
2.14 2.65 0.85 0.379
1.27b 24.4a 2.35a 14.1a 0.16c 47.5b 6.62e 0.47f 0.23a 0.98a 0.43e 0.076e 0.35d 0.10d ND 0.10d 0.12f 0.057d 40.6a 51.0b 8.32e 0.20f 7.53e 0.73f 10.2c
0.027 0.26 0.065 0.23 0.008 0.37 0.35 *
0.006 0.021 0.020 0.003 0.015 0.029 *
0.004 0.014 *
0.37 0.46 0.45 0.019 0.44 * *
Within a row, means lacking a common superscript letters differ (P < 0.05). T = tallow; HOSF = high-oleic sunflower oil; SFO = sunflower oil; LO = linseed oil; FB = fat blend (55% tallow, 35% sunflower oil, and 15% linseed oil); OB = oil blend (40% fish oil and 60% linseed oil); and NF = no added fat. B SFA = saturated fatty acids; MUFA = monounsaturated fatty acids; and PUFA = polyunsaturated fatty acids.ND: under detection limit. * SE was not calculated as comparisons were done on arcsine values because of the great difference that existed between treatments. A
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The sum of all MUFA, and particularly oleic (C18:1) and gadoleic (C20:1) acids, was highest (P < 0.05) in carcasses from HOSF-fed gilts, but palmitoleic acid (C16:1) was greatest (P < 0.05) in carcasses of gilts fed T and NF (Table 6). On the other hand, carcasses from gilts fed LO had the lowest (P < 0.05) percentage of all MUFA, whereas the proportion of C16:1 was lowest in SFO-fed gilt carcasses (P < 0.05) and the proportion of C18:1 was least in carcasses from gilts fed SFO, LO, and OB. Apple et al. (2009) also demonstrated that diets with no added fat and those formulated with 5% of beef tallow had greater MUFA percentages than a soybean oil diet with a lower degree of saturation. Carcasses from gilts fed SFO and LO had the greatest (P < 0.05) proportion of all PUFA (Table 6). More specifically, carcasses from SFO-fed gilts had the greatest (P < 0.05) proportion of n 6 PUFA, including linoleic (C18:2, n 6), eicosadienoic (C20:2, n 6), dihomo-c-linolenic (C20:3, n 6), arachidonic (20:4, n 6), and docosatetraenoic (22:4, n 6) acids, whereas carcasses of LO-fed gilts had the greatest (P < 0.05) percentages of all n 3 PUFA, in particular linolenic (C18:3, n 3) and eicosatrienoic (C20:3, n 3) acids. Enser et al. (2000) demonstrated that feeding linseed high in C18:3 (4.0 g/kg) increased DHA levels 50% in adipose tissue, 43% in liver and 35% in muscle when compared with a control diet with only 1.9 g/kg C18:3. However, Riley et al. (1998a), Riley et al. (1998b), Ahn, Lutz, and Sim (1996), and Specht-Overholt et al. (1997) failed to observe an increase in DHA by feeding larger amounts of linseed that were fed in the Enser et al. (2000) study. These authors proposed that much higher tissue concentrations of linolenic (C18:3) and EPA may result in competitive exclusion of DHA from tissue lipids, particularly from phospholipids. In this trial, levels of 18:3 were 18.9, 31.2 and 47.1 g/kg feed for the FB, OB and LO diets, respectively, indicating potential exclusion of DHA from phospholipid synthesis. Carcasses from gilts fed NF had the lowest (P < 0.05) percentages of all PUFA, and feeding gilts T produced carcasses with lower (P < 0.05) C18:2 and C18:3 percentages than the other fat sources. Other authors have also shown that proportions of PUFA are similar in carcass composite samples (Apple et al., 2009), backfat (Wiseman, Redshaw, Jagger, Nute, & Wood, 2000) and pork (Brooks, 1971) between pigs fed diets with no added fat and diets formulated with beef tallow. Nutritional recommendations for a healthy diet suggest that the ratio of PUFA-to-SFA (PUFA/SFA) should be 0.40, or higher, and intakes of n 3 PUFA should be increased relative to n 6 PUFA. A value of 4.0 or less for the diet as a whole is recommended for the n 6/n 3 ratio (Department of Health, 1994). Pork is characterized by a high content of C18:2, which leads to acceptable PUFA/SFA ratios, but the high content in n 6 FA usually results in unfavorable n 6/n 3 FA ratios from a human health perspective. The PUFA/SFA ratio was greatest (P < 0.05) in carcasses from gilts fed SFO and LO, whereas carcasses from NF-fed gilts produced the lowest PUFA/SFA ratio (Table 6). Furthermore, n 6/n 3 fatty acid ratio was excessively high in carcasses from SFO-fed gilts, and carcasses from gilts fed OB, LO and FB had n 6/n 3 FA ratios below the recommended 4.0 for a healthy human diet. Although an increase in the n 3 FA concentration is desirable from a human health standpoint, oxidative stability in meat is reduced. Altering the PUFA content in pork may have important implications for meat quality, such as pork firmness (Apple et al., 2007), shelf-life (Morel, McIntosh, & Janz, 2006) and flavor characteristics of meat (Wiseman et al., 2000) due to their greater susceptibility to oxidation and the production of volatile compounds during cooking. Warnants, Van Oeckel, and Boucqué (1996) proposed thresholds for PUFA in feed of 18 g/kg feed and for PUFA in backfat of 22%, whereas Bryhni, Kjos, Ofstad, and Hunt (2002) proposed less than 50 g PUFA/kg feed and 23% PUFA in backfat to help reduce oxidation problems indicating lower values for processed pork products. In this trial PUFA values in feed were 1.6,
611
16.1, 22.8, 74.5, 73.4, 45.2, and 70.8 g/kg and percentages of PUFA in carcasses were 8.3%, 13.5%, 14.0%, 30.8%, 31.1%, 20.9%, and 27.9% for NF, T, HOSF, SFO, LO, FB, and OB, respectively, indicating that high levels of fat addition, specifically SFO, LO and OB, may compromise sensory and technological quality of pork and pork products. 4. Conclusions Although the FA composition of the diet has major effects on carcass fatty acid composition, source of dietary fat in this study had only minimal effects on animal performance, carcass characteristics, and carcass fat content and distribution. Diets rich in PUFA did not reduce fat deposition in separable fat depots with respect to MUFA and SFA as previously shown in other species. Feeding a diet with no added fat may result in carcasses and primal cuts with a higher fat content compared with diets formulated with high levels of fat. As expected, carcass fatty acid composition reflected the fatty acid composition of the fat sources used in this experiment. Carcasses from gilts fed T had a high degree of saturation, with a FA composition similar to carcasses from NF-fed gilts. Carcasses from gilts fed FB and OB showed intermediate percentages in most fatty acids with higher n 3 fatty acids for OB than FB. Gilts fed HOSF resulted in carcasses with high percentage of MUFA, while carcasses from gilts fed SFO and LO showed high percentages of n 6 and n 3 FA, respectively. PUFA/SFA ratios were substantially increased by feeding gilts SFO, LO, OB, FB and HOSF, whereas carcasses from gilts fed FB, OB, LO had n 6/n 3 ratios within the recommended levels from a nutritional point of view. Ten percent addition o fat and particularly SFO, LO and OB may compromise technological and sensory quality of pork and pork products. Combinations of different fat sources (FB) and lower levels of fat addition may result in carcass fatty acid profiles with nutritional benefits without compromising pork quality. Acknowledgements This research was funded by the Spanish National Institute of Agricultural Research (INIA) corresponding to Project No. RTA03060-C2-1. References Ahn, D. H., Lutz, S., & Sim, J. S. (1996). Effects of dietary a-linolenic acid on the fatty acid composition, storage stability and sensory characteristics of pork loin. Meat Science, 43, 291–299. Allee, G. L., Romsos, D. R., Leveille, G. A., & Baker, D. H. (1972). Lipongenesis and enzymatic activity in pig adipose tissue as influenced by source of dietary fat. Journal of Animal Science, 35, 41–47. AOAC (1990). Official methods of analysis (15th ed.). Washington, DC: Association of Official Analytical Chemists. AOAC (2000). Official methods of analysis (16th ed.). Washington, DC: Association of Official Analytical Chemists. Apple, J. K., Maxwell, C. V., Galloway, D. L., Hamilton, C. R., & Yancey, J. W. S. (2009). Interactive effects of dietary fat source and slaughter weight in growingfinishing swine: III. Carcass and fatty acid compositions. Journal of Animal Science, 87, 1441–1454. Apple, J. K., Maxwell, C. V., Sawyer, J. T., Kutz, B. R., Rakes, L. K., Davis, M. E., et al. (2007). Interactive effect of ractopamine and dietary fat source on quality characteristics of fresh pork bellies. Journal of Animal Science, 85, 2682–2690. Bee, G., Gebert, S., & Messikommer, R. (2002). Effect of dietary energy supply and fat source on the fatty acid pattern of adipose and lean tissues and lipogenesis in the pig. Journal of Animal Science, 80, 1564–1574. Brooks, C. C. (1971). Fatty acid composition of pork lipids as affected by basal diet, fat source and fat level. Journal of Animal Science, 33, 1224–1231. Bryhni, E. A., Kjos, N. P., Ofstad, R., & Hunt, M. (2002). Polyunsaturated fat and fish oil in diets for growing-finishing pigs: Effects on fatty acid composition and meat, fat, and sausage quality. Meat Science, 62, 1–8. Crespo, N., & Esteve-Garcia, E. (2001). Dietary fatty acid profile modifies abdominal fat deposition in broiler chickens. Poultry Science, 80, 71–78. Crespo, N., & Esteve-Garcia, E. (2002a). Dietary polyunsaturated fatty acids decrease fat deposition in separable fat depots but not in the remainder carcass. Poultry Science, 81, 512–518.
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