All animal procedures were approved by the “Luiz de Queiroz” College of Agriculture Animal Care and Use Committee (University of São Paulo, Piracicaba, Brazil, number CEUA 2018-28) and adhered to the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching [17].
Animals, Experimental Design, And Housing
Ninety-six immunocastrated and halothane homozygous-negative (NN) male pigs (Large White sires x Large White dams) with an average initial body weight (BW) of 28.44 ± 2.95 kg and an average age of 71 ± 1.8 days were used in a 98-day feeding study. Pigs were randomly allotted to one of four dietary treatments with six replicate pens per treatment. Pigs were housed in an all-in/all-out double-curtain-sided building and reared in groups of four on partially slatted concrete floor pens. Overall pen size was 7.82 m2, which provided a floor space of 1.96 m2 per pig. Each pen was equipped with a three-hole dry self-feeder and a nipple drinker, allowing pigs ad libitum access to feed and water throughout the experimental period. Immunocastration of the intact males was performed by the administration of two 2-mL dose of Vivax® (Pfizer Animal Health, Parkville, Australia) at 127 and 141 days of age, in accordance with the manufacturer’s recommendations. The sires and dams that originated the population used herein were genotyped for the halothane mutation (RYR1 gene) according to Fujii et al. [18].
Experimental Diets
Pigs were fed a six-phase diet that was as follows: day 0 to 21 for grower I, day 21 to 42 for grower II, day 42 to 56 for finisher I, day 56 to 63 for finisher II, day 63 to 70 for finisher III, and day 70 to 98 for finisher IV. Dietary treatments consisted of corn-soybean meal growing-finishing diets supplemented with 1.5% SO (control) or 3% fat from either SO, CO, or FO. The canola-based oil treatment used in this study was high in OA content (64.2%) and low in alpha-linolenic acid (C18:3 n-3) content (7.6%) compared to traditional CO (56.1% OA and 9.3% C18:3 n-3) available on the market as described in NRC [16]. Diets were formulated to meet or exceed the nutrient requirements of growing-finishing pigs set by Rostagno et al. [19]. Standardized ileal digestible (SID) lysine-to-metabolizable energy ratio was maintained at 3.46, 3.16, 2.86, 2.86, 2.72, and 2.71 g/Mcal for the grower-I, grower-II, finisher-I, finisher-II, finisher-III, and finisher-IV diets, respectively (Table 1). Dietary treatments within each phase were formulated to contain equal amounts of SID lysine, methionine plus cysteine, threonine, and tryptophan. Amino acid content in the diets was balanced by supplementation with crystalline amino acids to maintain the ideal pattern suggested by Rostagno et al. [19].
Table 1
Composition of the experimental diets1 (as-fed basis)
| Grower I | | Grower II | | Finisher I | | Finisher II | | Finisher III | | Finisher IV |
| (day 0 to 21) | | (day 21 to 42) | | (day 42 to 56) | | (day 56 to 63) | | (day 63 to 70) | | (day 70 to 98) |
Item | Control | Fat | | Control | Fat | | Control | Fat | | Control | Fat | | Control | Fat | | Control | Fat |
Ingredient, % | | | | | | | | | | | | | | | | | |
Corn,7.5% CP2 | 63.47 | 61.88 | | 66.40 | 64.71 | | 69.13 | 67.54 | | 69.63 | 68.04 | | 69.59 | 68.00 | | 70.09 | 68.50 |
Soybean meal, 46% CP | 28.33 | 28.42 | | 26.10 | 26.29 | | 23.37 | 23.46 | | 23.37 | 23.46 | | 22.93 | 23.02 | | 22.93 | 23.02 |
Meat and bone meal, 44% CP | 3.00 | 3.00 | | 3.00 | 3.00 | | 3.00 | 3.00 | | 3.00 | 3.00 | | 3.00 | 3.00 | | 3.00 | 3.00 |
Fat source | 1.50 | 3.00 | | 1.50 | 3.00 | | 1.50 | 3.00 | | 1.50 | 3.00 | | 1.50 | 3.00 | | 1.50 | 3.00 |
Dicalcium phosphate | 0.55 | 0.56 | | 0.56 | 0.57 | | 0.26 | 0.27 | | 0.26 | 0.27 | | 0.27 | 0.27 | | 0.26 | 0.27 |
Limestone | 0.43 | 0.42 | | 0.38 | 0.38 | | 0.84 | 0.84 | | 0.76 | 0.75 | | 0.84 | 0.84 | | 0.69 | 0.69 |
Salt | 0.50 | 0.50 | | 0.50 | 0.50 | | 0.50 | 0.50 | | 0.50 | 0.50 | | 0.50 | 0.50 | | 0.50 | 0.50 |
Vitamin-mineral premix3 | 1.61 | 1.61 | | 1.08 | 1.08 | | 1.01 | 1.01 | | 0.60 | 0.60 | | 1.02 | 1.01 | | 0.66 | 0.65 |
L-Lysine.HCl | 0.35 | 0.35 | | 0.29 | 0.29 | | 0.25 | 0.25 | | 0.25 | 0.25 | | 0.20 | 0.20 | | 0.20 | 0.20 |
DL-Methionine | 0.11 | 0.11 | | 0.07 | 0.08 | | 0.04 | 0.04 | | 0.04 | 0.04 | | 0.02 | 0.02 | | 0.03 | 0.03 |
L-Threonine | 0.14 | 0.15 | | 0.11 | 0.11 | | 0.09 | 0.09 | | 0.09 | 0.09 | | 0.06 | 0.06 | | 0.06 | 0.07 |
L-Tryptophan | 0.01 | 0.01 | | - | - | | - | - | | - | - | | - | - | | - | - |
Ractopamine.HCl, 2% | - | - | | - | - | | - | - | | - | - | | 0.08 | 0.08 | | 0.08 | 0.08 |
Calculated composition | | | | | | | | | | | | | | | | | |
Metabolizable energy, Mcal/kg | 3.28 | 3.36 | | 3.29 | 3.36 | | 3.28 | 3.36 | | 3.29 | 3.36 | | 3.28 | 3.35 | | 3.29 | 3.36 |
Ether extract, % | 4.02 | 5.45 | | 4.05 | 5.48 | | 4.10 | 5.53 | | 4.10 | 5.53 | | 4.11 | 5.54 | | 4.11 | 5.54 |
CP, % | 19.71 | 19.64 | | 18.75 | 18.71 | | 17.66 | 17.58 | | 17.66 | 17.59 | | 17.41 | 17.33 | | 17.42 | 17.35 |
SID4 Lysine, % | 1.15 | 1.15 | | 1.05 | 1.05 | | 0.95 | 0.95 | | 0.95 | 0.95 | | 0.90 | 0.90 | | 0.90 | 0.90 |
SID Methionine + Cysteine, % | 0.62 | 0.62 | | 0.57 | 0.57 | | 0.51 | 0.51 | | 0.51 | 0.51 | | 0.49 | 0.49 | | 0.49 | 0.49 |
SID Threonine, % | 0.75 | 0.75 | | 0.68 | 0.68 | | 0.63 | 0.63 | | 0.63 | 0.63 | | 0.58 | 0.59 | | 0.59 | 0.59 |
SID Tryptophan, % | 0.22 | 0.22 | | 0.20 | 0.20 | | 0.18 | 0.18 | | 0.18 | 0.18 | | 0.18 | 0.18 | | 0.18 | 0.18 |
Calcium, % | 0.84 | 0.84 | | 0.81 | 0.81 | | 0.80 | 0.80 | | 0.77 | 0.77 | | 0.80 | 0.80 | | 0.75 | 0.75 |
Available Phosphorous, % | 0.42 | 0.42 | | 0.42 | 0.42 | | 0.34 | 0.34 | | 0.34 | 0.34 | | 0.34 | 0.34 | | 0.34 | 0.34 |
1The added fat sources consisted of corn-soybean meal grower-finisher diets with 1.5% soybean oil (SO; control) or 3% SO, canola oil (CO), or fish oil (FO). |
2CP = crude protein. |
3Provided per kilogram of diet: 6.500 UI vitamin A; 1.800 UI vitamin D3; 30 UI vitamin E; 2 mg vitamin K3; 1.2 mg vitamin B1; 3.4 mg vitamin B2; 2.0 mg vitamin B6; 125 mg Cu; 80 mg Fe; 40 mg Mn; 0.35 mg Se; 1.25 mg Zn. |
4SID = standardized ileal digestible. |
Growth Performance
Individual pig BW was measured on days 0, 21, 42, 56, 63, 70, and 98 to determine BW changes and average daily gain (ADG). All feed additions and feed remaining in the feeders at the time of pig weighing were recorded to calculate average daily feed intake (ADFI) and gain-to-feed (G:F).
Pig Slaughter And Carcass Data Collection
At the completion of the feeding trial (day 98), three pigs from each pen (n = 72; 18 pigs per treatment) were randomly chosen for slaughter to evaluate carcass and meat quality traits. Pigs were transported for approximately 503 km to a commercial pork packing plant (Frigodeliss, Capivari, SP, Brazil) and slaughtered according to the industry standards after a 16-hour rest period in the lairage pens, without feed but with free access to water. Animals were slaughtered by electrical stunning followed by exsanguination. After exsanguination, carcasses were scalded, dehaired, eviscerated, split vertically down the midline, inspected, and placed immediately into a 4 °C chill cooler. Hot carcass weight, including head and feet, was recorded at the time of slaughter to determine hot dressing percent. Chilled carcass weight was assessed 24 hours postmortem to obtain cold dressing percent. Shrink loss was calculated as the difference between hot and cold carcass weights [20]. The left carcass halves were ribbed between the 10th and 11th ribs, where the 10th-rib backfat depth was measured and the LL muscle area was outlined. The LL area was determined using the grid method. Percentage lean content of the carcasses was calculated using the equation for ribbed carcasses [21].
Meat Quality Assessment
The left side of each carcass was used to measure 45-minute and 24-hour postmortem pH on the exposed LL at the 10th rib using a HI-98163 pH meter with a stainless-steel probe (Hanna Instruments, Woonsocket, RI, USA). The left sides were then divided into primal cuts (ham, loin, belly, and shoulder) and LL sections were taken from the region of the 10th rib. Subsequently, center-cut loins were further processed into 2.5-cm-thick, trimmed of external fat and connective tissue, deboned, and used for pork quality data collection.
Drip and cooking losses were determined using the procedures outlined by Honikel [22] and AMSA [23], respectively, with modifications. Briefly, one chop from each loin section was weighed and suspended by a mesh inside an inflated and closed plastic bag. The set was placed in a chiller at 7 °C for 72 hours before being reweighed, and drip loss was calculated as a percentage of initial weight [22]. A second chop was weighed before cooking in an individual pan in a preheated 180 °C commercial oven to an internal temperature of 71 °C. The internal temperature was monitored with a hand-held digital thermometer (HM-600, Tatuapé, SP, Brazil) placed into the geometric center of each LL chop. Immediately after removal from the oven, chops were blotted dry on paper towels, allowed to cool to room temperature, and reweighed. Therefore, the difference between precooked and cooked weights was used to calculate cooking loss percentage.
The Warner-Bratzler shear force was measured as suggested by Honikel [22]. Briefly, six 1.27-cm-diameter cores from each cooked pork chop were obtained parallel to the muscle fiber orientation after chilling overnight at 4 °C. Cores were sheared once through the center using a Texture Analyzer TA-XT Plus (Stable Micro Systems, Godalming, England) attached to a Warner-Bratzler shear device with a crosshead speed of 3.33 mm/s. Samples were sheared perpendicular to the long axis of the core, and Warner-Bratzler shear force measurement was taken to be the peak force of the curve. The shear-force value for each chop was reported as the average of the shear-force values of the six cores. Finally, a third chop was vacuum-packaged and frozen at -20 °C until it was pulverized, oven-dried for 12 hours at 105 °C, and used for determination of ether extract (intramuscular fat) and fatty acid profile.
Fatty Acid Composition Analyses
Ether extract (intramuscular fat) was obtained from 5 g of LL muscle using the Soxhlet method according to AOAC [24]. For fatty acid profile determination, total lipid was isolated from 100 g of LL muscle following the cold extraction method proposed by Bligh and Dyer [25] and methylated according to the procedure outlined by AOCS [26]. Fatty acid methyl esters were quantified using a gas chromatograph (Shimadzu GC-2010 plus AF, Canby, OR, USA) equipped with a flame-ionization detector and a capillary column (Rtx-Wax, 30 m length x 0.32 mm i.d., 0.25 µm film thickness; Restek Corporation, Bellefonte, PA, USA). The temperature of the injector and of the flame-ionization detector was held constant at 250 °C and 280 °C, respectively, and the split ratio was 1:3. The flow rates were 1.2 mL.min− 1 for the carrier gas (H2), 30 mL.min− 1 for the auxiliary gas (N2), 30 and 300 mL.min− 1 for the flame gases H2 and synthetic air, respectively. The column temperature was programmed to initiate at 60 °C for 4 minutes, then the temperature was raised to 210 °C at a rate of 30 °C.min− 1, held there for 7 minutes, and finally increased to 250 °C at a rate of 30 °C.min− 1 and held constant for 18 minutes. Identification of the peaks was accomplished by using a purified standard (fatty acid methyl ester mixtures, from C8 to C22) obtained from Supelco Analytical (Bellefonte, PA, USA). The results were expressed as the percentage of the normalized area of the fatty acid peak.
The total proportion of SFA was the sum of the weight percentages of myristic (C14:0), palmitic (C16:0), and stearic (C18:0) acids. The total proportion of MUFA was calculated by summing the weight percentages of palmitoleic acid (C16:1), OA, and eicosenoic acid (C20:1 n-9). Additionally, the total percentage of PUFA included C18:2 n-6, C18:3 n-3, EPA, and DHA. The sum of all n-6 PUFA, comprised only by C18:2 n-6 in our study, was divided by the sum of all n-3 PUFA (C18:3 n-3, EPA, and DHA) to calculate the n-6:n-3 PUFA ratio, whereas the PUFA:SFA ratio was calculated by dividing the total proportion of PUFA by the total proportion of SFA. From the fatty acid analysis, iodine value was calculated using the following equation: (0.95 × [C16:1]) + (0.86 × [C18:1]) + (1.732 × [C18:2]) + (2.616 × [C18:3]) + (0.785 × [C20:1]), where brackets indicate the concentration (percentage) of the fatty acid [27]. Finally, the atherogenic index was calculated by using the formula of Ulbricht and Southgate [28]: (4 × [C14:0]) + (C16:0)/(total MUFA + total PUFA), where brackets also indicate the concentration (percentage) of the fatty acid.
Representative growing-finishing diet samples were obtained from each batch and then pooled by treatment in a composite sample for fatty acid composition analysis, which was performed by the same conditions described for LL muscle (Table 2, 3, and 4).
Table 2
Fatty acid composition (%) of grower diets1 (as-fed basis)
| Grower I (day 0 to 21) | | Grower II (day 21 to 42) |
Item | Control | SO | CO | FO | | Control | SO | CO | FO |
Saturated fatty acid (SFA) | | | | | | | | | |
Myristic acid (C14:0) | ND2 | 1.85 | ND | 0.24 | | 0.24 | 0.31 | 0.16 | 1.53 |
Palmitic acid (C16:0) | 13.97 | 12.76 | 10.82 | 20.36 | | 13.49 | 14.37 | 10.54 | 18.34 |
Margaric acid (C17:0) | ND | ND | ND | ND | | 0.15 | ND | ND | ND |
Stearic acid (C18:0) | 4.21 | 2.44 | 3.83 | 5.01 | | 4.01 | 4.50 | 3.13 | 4.52 |
Arachidic acid (C20:0) | 0.46 | ND | 0.57 | 0.35 | | 0.48 | 0.45 | 0.61 | 0.44 |
Behenic acid (C22:0) | 0.33 | ND | 0.26 | 0.16 | | 0.22 | 0.24 | 0.23 | ND |
Monounsaturated fatty acid (MUFA) | | | | | | | | | |
Palmitoleic acid (C16:1) | 0.30 | ND | ND | 3.45 | | 0.19 | 0.26 | 0.19 | 2.90 |
Oleic acid (C18:1 n-9) | 28.97 | 23.27 | 47.52 | 33.16 | | 33.21 | 31.92 | 49.72 | 37.65 |
Eicosenoic acid (C20:1 n-9) | 0.27 | ND | 0.64 | 0.88 | | 0.28 | 0.21 | 0.69 | 0.85 |
Polyunsaturated fatty acid (PUFA) | | | | | | | | | |
Linoleic acid (C18:2 n-6) | 47.62 | 55.65 | 32.02 | 29.94 | | 45.33 | 44.80 | 33.00 | 30.15 |
Alpha-linolenic acid (C18:3 n-3) | 3.57 | 5.85 | 4.31 | 1.62 | | 2.41 | 2.95 | 1.74 | 1.47 |
Eicosapentaenoic acid (C20:5 n-3, EPA) | ND | ND | ND | 1.06 | | ND | ND | ND | 0.83 |
Docosahexaenoic acid (C22:6 n-3, DHA) | ND | ND | ND | 1.78 | | ND | ND | ND | 1.33 |
Total SFA | 18.97 | 17.05 | 15.48 | 26.12 | | 18.59 | 19.87 | 14.67 | 24.83 |
Total MUFA | 29.54 | 23.27 | 48.16 | 37.49 | | 33.68 | 32.39 | 50.6 | 41.4 |
Total PUFA | 51.19 | 61.5 | 36.33 | 34.4 | | 47.74 | 47.75 | 34.74 | 33.78 |
PUFA:SFA ratio3 | 2.70 | 3.61 | 2.35 | 1.32 | | 2.57 | 2.40 | 2.37 | 1.36 |
Iodine value4 | 117.23 | 131.70 | 108.10 | 88.58 | | 113.78 | 113.17 | 105.19 | 91.87 |
1Pigs (n = 96) were fed either a corn-soybean meal grower-finisher diets containing 1.5% soybean oil (SO; control) or diets containing 3% SO, canola oil (CO), or fish oil (FO). |
2ND = not detectable. |
3PUFA:SFA ratio = total PUFA/total SFA. |
4Iodine value = (0.95 × [C16:1]) + (0.86 × [C18:1]) + (1.732 × [C18:2]) + (2.616 × [C18:3]) + (0.785 × [C20:1]), where brackets indicate concentrations [27]. |
Table 3
Fatty acid composition (%) of finisher diets1 (as-fed basis)
| Finisher I (day 42 to 56) | | Finisher II (day 56 to 63) |
Item | Control | SO | CO | FO | | Control | SO | CO | FO |
Saturated fatty acid (SFA) | | | | | | | | | |
Myristic acid (C14:0) | 0.29 | 1.87 | ND2 | ND | | ND | ND | 0.16 | 1.75 |
Palmitic acid (C16:0) | 13.62 | 19.75 | 10.64 | 13.72 | | 11.88 | 12.59 | 10.06 | 19.30 |
Margaric acid (C17:0) | ND | 0.34 | ND | ND | | ND | ND | 0.07 | 0.24 |
Stearic acid (C18:0) | 4.29 | 4.96 | 3.35 | 4.42 | | 3.13 | 2.83 | 2.40 | 4.12 |
Arachidic acid (C20:0) | 0.43 | 0.43 | 0.57 | 0.35 | | 0.42 | 0.41 | 0.58 | 0.36 |
Behenic acid (C22:0) | ND | ND | ND | 0.13 | | 0.32 | 0.21 | 0.25 | ND |
Monounsaturated fatty acid (MUFA) | | | | | | | | | |
Palmitoleic acid (C16:1) | 0.21 | 3.49 | 0.27 | 0.19 | | 0.11 | 0.11 | 0.28 | 3.50 |
Oleic acid (C18:1 n-9) | 35.64 | 36.44 | 52.98 | 35.96 | | 30.79 | 34.84 | 52.58 | 36.62 |
Eicosenoic acid (C20:1 n-9) | ND | ND | 0.71 | 0.78 | | 0.20 | 0.23 | 0.73 | 0.92 |
Polyunsaturated fatty acid (PUFA) | | | | | | | | | |
Linoleic acid (C18:2 n-6) | 42.82 | 27.52 | 30.34 | 43.04 | | 48.90 | 46.03 | 31.64 | 28.79 |
Alpha-linolenic acid (C18:3 n-3) | 2.70 | 1.65 | 1.13 | 2.67 | | 4.26 | 2.76 | 1.09 | 1.57 |
Eicosapentaenoic acid (C20:5 n-3, EPA) | ND | ND | ND | 1.02 | | ND | ND | ND | 1.04 |
Docosahexaenoic acid (C22:6 n-3, DHA) | ND | ND | ND | 1.73 | | ND | ND | ND | 1.79 |
Total SFA | 18.63 | 27.35 | 14.56 | 18.62 | | 15.75 | 16.04 | 13.52 | 25.77 |
Total MUFA | 35.85 | 39.93 | 53.96 | 36.93 | | 31.1 | 35.18 | 53.59 | 41.04 |
Total PUFA | 45.52 | 29.17 | 31.47 | 48.46 | | 53.16 | 48.79 | 32.73 | 33.19 |
PUFA:SFA ratio3 | 2.44 | 1.07 | 2.16 | 2.60 | | 3.38 | 3.04 | 2.42 | 1.29 |
Iodine value4 | 112.08 | 86.63 | 101.88 | 113.25 | | 122.58 | 117.19 | 103.71 | 89.51 |
1Pigs (n = 96) were fed either a corn-soybean meal grower-finisher diets containing 1.5% soybean oil (SO; control) or diets containing 3% SO, canola oil (CO), or fish oil (FO). |
2ND = not detectable. |
3PUFA:SFA ratio = total PUFA/total SFA. |
4Iodine value = (0.95 × [C16:1]) + (0.86 × [C18:1]) + (1.732 × [C18:2]) + (2.616 × [C18:3]) + (0.785 × [C20:1]), where brackets indicate concentrations [27]. |
Table 4
Fatty acid composition (%) of finisher diets1 (as-fed basis)
| Finisher III (day 63 to 70) | | Finisher IV (day 70 to 98) |
Item | Control | SO | CO | FO | | Control | SO | CO | FO |
Saturated fatty acid (SFA) | | | | | | | | | |
Myristic acid (C14:0) | 0.43 | 0.28 | 0.25 | 1.88 | | ND2 | ND | ND | 1.90 |
Palmitic acid (C16:0) | 13.61 | 13.82 | 10.71 | 20.02 | | 12.90 | 14.45 | 10.60 | 20.11 |
Margaric acid (C17:0) | ND | 0.16 | 0.13 | ND | | ND | ND | ND | ND |
Stearic acid (C18:0) | 4.98 | 4.28 | 3.61 | 5.06 | | 3.81 | 4.53 | 3.39 | 4.73 |
Arachidic acid (C20:0) | 0.40 | 0.43 | 0.54 | ND | | ND | 0.43 | 0.58 | ND |
Behenic acid (C22:0) | ND | 0.19 | 0.26 | ND | | ND | ND | ND | ND |
Monounsaturated fatty acid (MUFA) | | | | | | | | | |
Palmitoleic acid (C16:1) | 0.54 | 0.32 | 0.24 | 3.52 | | ND | 0.22 | 0.39 | 3.61 |
Oleic acid (C18:1 n-9) | 33.32 | 34.95 | 48.67 | 36.77 | | 30.18 | 35.58 | 52.26 | 35.44 |
Eicosenoic acid (C20:1 n-9) | 0.32 | 0.26 | 0.62 | ND | | 0.42 | ND | 0.71 | 0.90 |
Polyunsaturated fatty acid (PUFA) | | | | | | | | | |
Linoleic acid (C18:2 n-6) | 42.63 | 42.85 | 33.47 | 28.41 | | 48.53 | 42.56 | 30.99 | 28.92 |
Alpha-linolenic acid (C18:3 n-3) | 3.78 | 2.45 | 1.51 | 1.52 | | 4.16 | 2.24 | 1.07 | 1.55 |
Eicosapentaenoic acid (C20:5 n-3, EPA) | ND | ND | ND | 1.05 | | ND | ND | ND | 1.07 |
Docosahexaenoic acid (C22:6 n-3, DHA) | ND | ND | ND | 1.78 | | ND | ND | ND | 1.77 |
Total SFA | 19.42 | 19.16 | 15.5 | 26.96 | | 16.71 | 19.41 | 14.57 | 26.74 |
Total MUFA | 34.18 | 35.53 | 49.53 | 40.29 | | 30.6 | 35.8 | 53.36 | 39.95 |
Total PUFA | 46.41 | 45.3 | 34.98 | 32.76 | | 52.69 | 44.8 | 32.06 | 33.31 |
PUFA:SFA ratio3 | 2.39 | 2.36 | 2.26 | 1.22 | | 3.15 | 2.31 | 2.20 | 1.25 |
Iodine value4 | 113.14 | 111.19 | 104.49 | 88.15 | | 121.22 | 110.38 | 102.35 | 88.76 |
1Pigs (n = 96) were fed either a corn-soybean meal grower-finisher diets containing 1.5% soybean oil (SO; control) or diets containing 3% SO, canola oil (CO), or fish oil (FO). |
2ND = not detectable. |
3PUFA:SFA ratio = total PUFA/total SFA. |
4Iodine value = (0.95 × [C16:1]) + (0.86 × [C18:1]) + (1.732 × [C18:2]) + (2.616 × [C18:3]) + (0.785 × [C20:1]), where brackets indicate concentrations [27]. |
Overall Liking
The chops were thawed at 4 °C overnight before cooking on an electric grill to an internal temperature of 71 °C, which was monitored by individual thermometers inserted into the center of each chop. Subsequently, cooked chops were cut into 10 g cubes and wrapped with aluminum foil to avoid temperature loss during serving. The consumer tests were carried out in individual booths under artificial white light. The samples were placed in 50 mL disposable plastic cups, coded with three-digit random numbers, and served in a sequential monadic order according to a Williams Latin square design. Filtered water and crackers were served as palate cleansers in-between samples. The panel consisted of 101 regular pork consumers (60% females and 40% males, age ranged from 18 to 65 years old), which were recruited from students and staffs of the “Luiz de Queiroz” College of Agriculture, University of São Paulo. In a single session, each panelist evaluated the four treatments (one sample per treatment) for overall liking using a nine-point hedonic scale (1 = extremely dislike; 5 = neither like nor dislike; 9 = extremely like) [29]. Data were collected by Compusense Cloud (Compusense Inc., Guelph, ON, Canada) using tablets (Samsung Galaxy Table E, T560, screen 9.6′′). All consumer panelists filled out a consent form, which was previously approved by the Ethics Committee of the “Luiz de Queiroz” College of Agriculture (University of São Paulo, Piracicaba, Brazil, number CAAE 04352718.6.0000.5395).
Statistical Analyses
Excepted for overall liking, all other data were analyzed as a randomized complete block design using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) for repeated measures, and pen was considered the experimental unit. Outliers were removed from the data sets and residuals were tested for a normal distribution using the Shapiro-Wilk test (UNIVARIATE procedure). Non-normally distributed data were log-transformed for analysis and back-transformed for presentation. Growth performance data were analyzed as repeated measures over time, and the model included dietary treatment, time, and the two-way interaction as the fixed effects, block and pen as the random effects, and pen (nested within treatment) as the subject of the REPEATED statement. For each analyzed variable, data were subjected to five covariance structures: variance components, compound symmetry, first-order autoregressive, heterogeneous first-order autoregressive, and unstructured. The covariance structure that yielded the smallest Bayesian information criterion (BIC) was used for the results presented. For carcass characteristics, meat quality, and fatty acid composition data, dietary treatment and block were included as the fixed and random effects, respectively, in the model. The LSMEANS option was used to generate treatment means, which were separated using the PDIFF option based on Student’s t test. Significance was declared at P ≤ 0.05, and trends were discussed at 0.05 < P ≤ 0.10. Data from overall liking were analyzed by the non-parametric Friedman test at 5% probability.