Introduction
Pork is the most consumed meat globally, and the global demand for pork continues to increase (Organization for Economic Co-operation and Development: Food and Agriculture Organization of the United Nations, 2025). Increasing the market weights of pigs will be a logical strategy to meet the growing demand for pork. The increasing cost of feed ingredients has driven producers to explore a variety of byproducts, such as beef tallow (TW), in swine diet. Diet plays a major role in body composition, specifically fat composition, of pigs because the composition and level of fat in the diet affect the biochemistry and quantity of fat deposited in pigs. In this perspective, the fatty acid composition is important to pork quality due to its effects on fat firmness and susceptibility to lipid oxidation (Shurson, 2019). The composition of fat in pork carcasses is closely related to the dietary fatty acid profile (Kellner et al., 2014), and a high content of unsaturated fatty acids in swine diet can lead to soft fat in pork carcasses. A decline in pork quality and product value may occur when increasing pig slaughter weight (Metz et al., 2024) due to the longer feeding periods on diets high in polyunsaturated fats.
Vitamin E is an antioxidant supplement used in animal feeds that contributes to decreasing oxidative stress (Ralla et al., 2024) and improving oxidative stability as well as the shelf life of fresh pork (Boler et al., 2009). Wang et al. (2012) documented that supplementation with high levels of vitamin E decreased lipid oxidation in meat from pigs fed diets high in dried distillers’ grains with solubles. Therefore, increasing dietary vitamin E levels could increase lipid stability of pork containing highly unsaturated fatty acids (Guo et al., 2006). α-tocopherol is the commonly used isoform of vitamin E in swine diets (Shastak and Pelletier, 2025), whereas γ-tocopherol (GT) is the predominant isoform in human diet (Jiang et al., 2001). Furthermore, GT is more effective in chelating lipophilic electrophiles than α-tocopherol (Jiang et al., 2001). Although the absorption rates of α-tocopherol and GT are similar, the elimination of GT from plasma is faster (Leonard et al., 2005), which might imply either faster excretion or faster incorporation into tissue. A more rapid incorporation into tissue could be beneficial for improving meat quality, especially in preventing lipid oxidation in meat.
Vitamin E isoforms and fat sources high in saturated fatty acids could be used in swine diets to increase oxidative stability of pork. However, the interactions among vitamin E isoforms, fat sources, and fresh pork quality are rarely reported. Although heavy slaughter weight pigs could be used to meet the increasing demand of pork, there has been very limited research on the impact of heavy slaughter weight on fresh pork quality. In this perspective, the objective of the study was to evaluate the effect of 2 fat sources that differed in fatty acid profile on carcass characteristics and meat quality of pigs grown to heavy slaughter weights and their potential interactions with the isoforms and levels of vitamin E.
Materials and Methods
The experiment was conducted under protocols approved by the Institutional Animal Care and Use Committee of the University of Kentucky. The growth and feeding phase of the experiment was carried out in environmentally controlled rooms at the University of Kentucky’s Swine Research Center. The slaughter and sample collection were performed at the US Department of Agriculture (USDA) inspected Meat Science Laboratory of the University of Kentucky.
Animals, diet, and experimental design
A total of 72 individually fed pigs (n = 72; 36 barrows and 36 gilts; initial body weight ∼24–30 kg) were blocked by sire, body weight, and sex, and then randomly assigned to individual pens. Pens were randomly assigned to 1 of the 12 dietary treatments in a 2 × 6 factorial arrangement. Fat treatments included 5% TW and 5% corn oil (CO). Vitamin E treatments included 4 levels of α-tocopheryl-acetate (ATA; 11, 40, 100 and 200 ppm) and 2 levels of mixed tocopherols, primarily GT (40 and 100 ppm). Of these levels, 11 ppm represented the dietary vitamin E requirement for growing-finishing pigs (National Research Council, 2012), whereas the others were elevated levels to assure biological responses in pigs (Wang et al., 2023). The diets were corn-soybean meal based in mash form and were fed for 5 body weight phases, including 25 kg to 50 kg (phase 1), 50 kg to 75 kg (phase 2), 75 kg to 100 kg (phase 3), 100 kg to 125 kg (phase 4), and 125 kg to 150 kg (phase 5). All experimental diets were formulated to meet or exceed the National Research Council (2012) nutrient requirement estimates for growing-finishing pigs. Formulations for each phase are listed in Table 1. Treatment diets were fed to pigs up until slaughter, and the slaughter weight was close to 150 kg.
Basal composition of diets with different fat sources1 and vitamin E isoforms2 from phase 1 to phase 5 (as-fed basis).
| Ingredient, % | Phase 1 | Phase 2 | Phase 3 | Phase 4 | Phase 5 |
|---|---|---|---|---|---|
| Corn | 62.85 | 69.55 | 73.81 | 77.04 | 80.17 |
| Soybean meal (48% crude protein) | 28.50 | 22.00 | 18.00 | 15.00 | 12.00 |
| Fat source (TW or CO) | 5.00 | 5.00 | 5.00 | 5.00 | 5.00 |
| L-lysine HCl | 0.22 | 0.24 | 0.21 | 0.17 | 0.22 |
| DL-methionine | 0.12 | 0.09 | 0.04 | 0.01 | 0.01 |
| L-threonine | 0.09 | 0.09 | 0.06 | 0.04 | 0.05 |
| Limestone | 1.08 | 0.99 | 0.88 | 0.77 | 0.68 |
| Dicalcium phosphate | 0.92 | 0.82 | 0.78 | 0.75 | 0.65 |
| Salt | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 |
| Vitamin premix3 | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 |
| Mineral premix4 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 |
| Choline5 | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 |
| Santoquin6 | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 |
| AB-207 | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 |
| Total | 100.00 | 100.00 | 100.00 | 100.00 | 100.00 |
| Calculated Nutrient Level, % | Phase 1 | Phase 2 | Phase 3 | Phase 4 | Phase 5 |
| ME, Mcal/kg | 3.47 | 3.49 | 3.50 | 3.50 | 3.51 |
| Crude protein, % | 19.13 | 16.58 | 14.94 | 13.70 | 12.59 |
| SID Lys | 1.04 | 0.90 | 0.78 | 0.67 | 0.64 |
| SID Lys/ME | 2.99 | 2.58 | 2.22 | 1.92 | 1.82 |
| SID Met | 0.38 | 0.32 | 0.26 | 0.21 | 0.20 |
| SID Cys | 0.26 | 0.24 | 0.22 | 0.21 | 0.19 |
| SID M + C | 0.65 | 0.55 | 0.47 | 0.42 | 0.39 |
| SID Arg | 1.13 | 0.94 | 0.82 | 0.73 | 0.65 |
| SID His | 0.45 | 0.39 | 0.35 | 0.33 | 0.30 |
| SID Ile | 0.69 | 0.58 | 0.51 | 0.46 | 0.41 |
| SID Leu | 1.43 | 1.28 | 1.19 | 1.12 | 1.05 |
| SID Phe | 0.81 | 0.70 | 0.62 | 0.57 | 0.52 |
| SID Tyr | 0.53 | 0.45 | 0.40 | 0.37 | 0.33 |
| SID P + T | 1.34 | 1.15 | 1.03 | 0.94 | 0.85 |
| SID Thr | 0.67 | 0.58 | 0.50 | 0.44 | 0.41 |
| SID Trp | 0.20 | 0.17 | 0.14 | 0.13 | 0.11 |
| SID Val | 0.75 | 0.64 | 0.58 | 0.53 | 0.48 |
| SID Ca | 0.7 | 0.62 | 0.56 | 0.51 | 0.44 |
| Total P | 0.54 | 0.49 | 0.46 | 0.45 | 0.41 |
| STTD P | 0.32 | 0.29 | 0.27 | 0.26 | 0.23 |
AB, XXX; DL, XXX; HCl, hydrochloric acid; ME, metabolizable energy; SID, standardized ileal digestibility; STTD P, standardized total tract digestible phosphorus.
Fat sources included corn oil (CO) and tallow (TW).
Vitamin E supplementation included α-tocopheryl-acetate at 4 levels (11, 40, 100, and 200 ppm) and γ-tocopherol at 2 levels (40 and 100 ppm).
Composition per kg of diet: 7,000 IU of vitamin A, 1,500 IU of vitamin D3, 2.0 mg of vitamin K, 0.03 mg of vitamin B12, 7.0 mg of riboflavin, 25.0 mg of pantothenic acid, 20.0 mg of niacin, 1.0 mg of folic acid, 2.5 mg of vitamin B6, 2.0 mg of thiamin, and 0.15 mg of biotin.
Composition per kg of added fat diet: 50 mg of Mn as manganese hydroxychloride, 100 mg of Fe as ferrous sulfate monohydrate, 125 mg of Zn as zinc hydroxychloride, 20 of Cu as tribasic copper chloride, 0.35 mg of I as calcium iodate, and 0.30 mg of Se as sodium selenite.
Provided 150 mg/kg of choline to the final diet.
Santoquin (Monsanto, St. Louis, Missouri, USA) supplied 130 mg/kg ethoxyquin to the final diet.
Clay product from Prince Agri Products, Inc., Quincy Illinois, USA.
The ATA was supplied as DL (all-rac)-ATA (ROVIMIX E 50 ADS, DSM Nutritional Products, Inc., New Jersey, USA) in a dry form. The mixed tocopherols were supplied as mixed tocopherols 95 (DSM Nutritional Products, Inc., New Jersey, USA) in liquid form, which contained 0% to 15% α-tocopherol, less than 5% β-tocopherol, 55% to 75% GT, and 20% to 30% δ-tocopherol.
Slaughter, carcass fabrication, and carcass characteristics
Pigs were humanely slaughtered at approximately 150 kg live weight at the University of Kentucky’s USDA-inspected Meat Laboratory according to standard industry practice. Pigs were weighed (slaughter weight) and were harvested under the supervision of the USDA Food Safety and Inspection Service. At 45 min postmortem, pH of longissimus thoracis muscle at the location between the 10th and 11th rib was recorded with an Accumet 50 pH meter (Fisher Scientific, Fairlawn, New Jersey, USA). Hot carcass weight was recorded and was used to calculate dressing percentage as below:
All carcass measurements were performed according to the methods described by McClelland et al. (2012). Following a 24 h chill (4°C), cold carcass weight, fat depth at the 10th rib, 1st rib, last rib, and last lumbar were measured on the left side of each carcass. Carcass length was measured from the anterior edge of the symphysis pubic to the recess of the first rib. The Boston butt (IMPS # 406), shoulder picnic (IMPS # 405), loin (IMPS # 412), belly (IMPS # 408; squared at each end), and spareribs were removed and weighed individually according to Institutional Meat Purchasing Specifications (North American Meat Processors Association, 2010). Primal cuts were recorded in absolute weight (weight in kg of the primal) and relative weight ([primal cut, kg/hot carcass weight] × 100).
After weighing the loin, it was deboned, and the muscle section (longissimus thoracis) anterior to the 10th rib location was removed for further analysis. Two 2.54-cm thick chops were fabricated from the 10th rib location. The 1st chop was used for color evaluation, whereas the 2nd one was used for drip loss. The remaining section (10 cm) was used to measure purge loss. Belly depth was measured in 6 locations that were evenly divided into rectangles from the shoulder to flank end before being measured for belly flex. Longissimus muscle area and 24-h pH (Accumet 50 pH meter Fisher Scientific, Fairlawn, New Jersey, USA) were also measured from the left side of each carcass according to methods described by the National Pork Producers Council (2000).
Belly flex was measured to determine belly firmness using an objective test developed by Rentfrow et al. (2003). The spareribs, related cartilage, and remaining leaf fat were removed, and the bellies were squared. The fresh bellies with the skin on were then centered, skin side down, on a 7.5-cm diameter polyvinyl chloride (PVC) pipe mounted perpendicular to a board marked with a 2.54-cm grid matrix. Lateral and vertical flexes were determined from the degree of belly flex relative to the grid matrix. A vertical belly flex of 0 meant the belly was parallel to the floor and completely stiff. A lateral belly flex of 10 cm meant that the belly flexed to a point where there were 10 cm between the end of the squared belly and a vertical line directly below the center of the supporting PVC pipe. Thus, a lower lateral flex and a greater vertical flex indicated a softer, more flexible, belly. The belly flex measurements were determined in a room maintained at 7°C.
Meat quality measurements
The loin (longissimus thoracis) was utilized for evaluation of meat quality because this muscle has been widely utilized for studying fresh pork quality traits (Barkley et al., 2023; Beyer et al., 2023).
Drip loss and purge loss
Drip loss was determined by suspending the 2.54-cm thick chop from a hook covered with a plastic bag and stored at 4°C for 48 h. The samples were weighed before and after hanging, and drip loss percentage was determined by the following equation:
For purge loss, a 10-cm section of longissimus thoracis, anterior to the 10th rib, was weighed prior to being vacuum packaged, boxed, and stored under refrigeration (4°C) for 30 d to simulate the period between the packing plant and the retail grocery store. Loin samples were reweighed at days 7, 14, and 30 to determine purge loss at each stage to determine when most of the weight was lost during storage. Before reweighing the samples, they were taken out of the vacuum package, and surface water was removed with a paper towel. The samples were vacuum packaged, reweighed, and stored in the same conditions. All sample handling was conducted at 4°C.
Instrumental color evaluation
For color measurements, a 2.54-cm chop was removed from the longissimus thoracis immediately at 24 h postmortem and was placed on foam trays, which were then overwrapped in PVC film. The overwrapped chops were stored under retail display (1,300 lux light intensity) at 2°C for 7 d. Objective color was evaluated on days 1, 3, 5, and 7 using a HunterLab MiniScan XE colorimeter (HunterLab Associates, Reston, Virginia, USA) with a 2.54-cm diameter aperture, illuminant A, and 10° standard observer. Lightness (L*), redness (a*), yellowness (b*), hue, and chroma values were recorded from 3 random locations on the surfaces (King et al., 2023). Prior to color analysis, the colorimeter was standardized with black and white tiles overwrapped with PVC film to adjust for the PVC overwrap on the samples.
Lipid oxidation
Lipid oxidation was determined utilizing the method as described by Yin et al. (1993). Samples (5 g) from the longissimus thoracis were homogenized with 22.5 mL of 11% trichloroacetic acid solution and filtered through Whatman no. 1 paper. Two mL filtrates were mixed with 2 mL of aqueous solution of thiobarbituric acid (20 mM) and incubated at 25°C for 20 h. The absorbance values at 532 nm were measured using a UV-1800 spectrophotometer (Shimadzu Corporation, Kyoto, Japan) and were presented as thiobarbituric acid reactive substances (TBARS).
Statistical analysis
Data analysis was performed in SAS (SAS Institute Inc., Cary, NC) by least-squares mean analysis of variance using the generalized linear model as a randomized complete block design. The individual pig served as the experimental unit. Shelf-life data were analyzed as repeated measures to determine the trends over time. Regression and contrasts were performed when interactions between time and main effect were observed. Statistical differences were established at P ≤ .05, tendencies were established at P ≤ .10. In the tables, all P values greater than .20 were replaced as “-”. With respect to the effects of ATA levels and fat sources, P values for the main effects are provided, and the interactions (P ≤ .05) between ATA levels and fat sources are indicated in the tables. For the evaluation of isoforms, only P values for the effects of isoform and their interactions with main effects (fat sources and levels of isoforms) are provided in the tables.
Results
Carcass traits and primal cuts
The results of carcass traits are presented in Table 2. There were no differences in hot carcass weight, cold carcass weight, shrink loss, carcass length, back fat depth, and loin muscle area among different dietary treatments. Overall, an increase in dietary levels of ATA from 11 to 200 ppm in both TW and CO diets increased the slaughter weight (linear, P = .04). Additionally, 45-min pH (quadratic, P = .02) and 24-hour pH (quadratic, P = .02) were also affected by the increase in ATA levels. Interactions between isoforms of vitamin E and fat sources were observed for ΔpH (P = .03). Increasing the level of GT from 40 ppm to 100 ppm in both TW and CO diets led to an increase in the ΔpH, whereas such an increase in ΔpH was observed in ATA only in TW diet. Carcasses of pigs fed TW had greater dressing percentages (P = .04) and greater belly depth (P = .04) than those from pigs fed CO.
Effect of different fat sources and vitamin E isoforms on carcass traits of heavy slaughter weight (150 kg) pigs.
| Parameters | Fat Source1 | Vitamin E IF2 | P Value | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ATA, ppm | GT, ppm | ATA Level3 | Fat | IF | |||||||||
| 11 | 40 | 100 | 200 | 40 | 100 | L | Q | IF | IF×Level | IF×Fat | |||
| Slaughter wt, kg | TW | 146.24 | 148.23 | 147.49 | 147.87 | 145.23 | 147.51 | .04 | - | - | - | - | - |
| CO | 146.06 | 148.21 | 148.02 | 151.12 | 149.08 | 147.24 | |||||||
| Hot carcass wt, kg | TW | 113.17 | 114.44 | 114.53 | 113.62 | 111.17 | 112.81 | .09 | - | - | - | - | .14 |
| CO | 111.87 | 112.77 | 113.89 | 115.44 | 114.19 | 112.35 | |||||||
| Cold carcass wt, kg | TW | 110.54 | 111.58 | 111.13 | 110.62 | 109.09 | 109.27 | .14 | - | - | .17 | - | - |
| CO | 109.15 | 109.54 | 111.36 | 112.79 | 110.03 | 109.72 | |||||||
| Dressing % | TW | 77.41 | 77.21 | 77.65 | 76.99 | 77.21 | 76.62 | - | - | .04 | - | - | - |
| CO | 76.29 | 76.09 | 76.36 | 76.42 | 76.61 | 76.30 | |||||||
| Shrink loss % | TW | 2.33 | 2.48 | 2.30 | 2.60 | 1.87 | 2.38 | - | - | .07 | - | - | .11 |
| CO | 2.36 | 1.66 | 2.23 | 1.49 | 2.40 | 2.34 | |||||||
| 45-min pH | TW | 5.90 | 6.13 | 6.09 | 5.91 | 6.02 | 5.99 | - | .02 | - | .15 | - | - |
| CO | 5.87 | 6.19 | 6.10 | 6.10 | 6.12 | 6.00 | |||||||
| 24-h pH | TW | 5.59 | 5.71 | 5.66 | 5.53 | 5.64 | 5.65 | - | .02 | - | - | - | - |
| CO | 5.49 | 5.65 | 5.70 | 5.72 | 5.75 | 5.57 | |||||||
| ΔpH | TW | 0.31 | 0.42 | 0.41 | 0.42 | 0.30 | 0.35 | - | - | - | .19 | - | .03 |
| CO | 0.33 | 0.54 | 0.32 | 0.38 | 0.34 | 0.43 | |||||||
| Carcass length, cm | TW | 82.07 | 84.14 | 83.71 | 83.82 | 82.55 | 82.44 | - | - | - | - | - | - |
| CO | 82.42 | 85.25 | 82.80 | 84.24 | 85.09 | 82.02 | |||||||
| Back fat depth, cm | |||||||||||||
| First rib | TW | 4.17 | 4.93 | 5.13 | 4.88 | 4.85 | 4.61 | - | - | - | - | - | - |
| CO | 4.93 | 4.51 | 4.62 | 4.78 | 4.74 | 5.03 | |||||||
| Last rib | TW | 3.35 | 3.71 | 3.43 | 3.24 | 3.60 | 3.77 | - | - | - | - | - | - |
| CO | 3.33 | 3.40 | 3.43 | 3.43 | 3.26 | 3.56 | |||||||
| 10th rib | TW | 2.69 | 2.90 | 3.01 | 2.60 | 3.05 | 3.22 | - | - | - | - | - | - |
| CO | 3.15 | 2.86 | 3.22 | 2.90 | 2.67 | 2.69 | |||||||
| Last lumbar | TW | 2.34 | 2.72 | 2.12 | 1.73 | 2.29 | 2.18 | .11 | - | - | - | - | - |
| CO | 2.29 | 2.48 | 2.46 | 2.41 | 2.58 | 1.98 | |||||||
| Belly depth, cm | TW | 5.15 | 5.23 | 5.13 | 4.94 | 5.21 | 5.05 | - | - | .04 | - | - | - |
| CO | 4.63 | 4.95 | 4.81 | 4.83 | 4.85 | 4.42 | |||||||
| Loin muscle dimensions | |||||||||||||
| Vertical4, cm | TW | 7.37 | 7.01 | 7.75 | 7.21 | 7.62 | 7.28 | - | - | - | - | - | - |
| CO | 7.16 | 7.18 | 6.86 | 7.58 | 7.26 | 7.57 | |||||||
| Horizontal5, cm | TW | 10.82 | 10.57 | 10.58 | 10.41 | 10.29 | 10.80 | - | - | - | - | - | - |
| CO | 10.21 | 10.61 | 10.46 | 11.01 | 10.29 | 10.26 | |||||||
| Area, cm2 | TW | 61.04 | 58.84 | 58.52 | 59.49 | 62.05 | 61.40 | - | - | .17 | - | - | - |
| CO | 56.39 | 57.64 | 56.00 | 58.58 | 54.30 | 57.87 | |||||||
Fat sources included corn oil (CO) and tallow (TW).
Vitamin E supplementation included α-tocopheryl-acetate (ATA) at 4 levels (11, 40, 100, and 200 ppm) and γ-tocopherol (GT) at 2 levels (40 and 100 ppm). IF, isoforms.
Linear (L) and quadratic (Q) responses are based on 4 levels of ATA.
Depth vertical to the 10th rib.
Width horizontal to the 10th rib.
The data of primal cut absolute (kg) and relative (%) weight are provided in Table 3. Belly from pigs fed GT had a lower relative weight (P = .02) than those from pigs fed ATA. Interactions between fat and dietary ATA level were observed for absolute weight (kg) and relative weight (%) for picnic shoulder (P < .05). At lower levels of ATA (11, 40, and 100 ppm), TW diets resulted in greater (P < .05) absolute and relative weight for picnic shoulder than CO diet. On the other hand, at 200 ppm ATA, pigs fed CO diet had greater (P < .05) absolute and relative weight for picnic shoulder than those fed TW diet. There were no other impacts of vitamin E isoforms, levels, and fat source on the absolute weight (kg) and relative weight (%) of primal cuts.
Effect of different fat sources and vitamin E isoforms on primal cuts from heavy slaughter weight (150 kg) pigs.
| Parameters | Fat Source1 | Vitamin E IF2 | P Value | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ATA, ppm | GT, ppm | ATA Level3 | Fat | IF | |||||||||
| 11 | 40 | 100 | 200 | 40 | 100 | L | Q | IF | IF×Level | IF×Fat | |||
| Primal cuts (kg) | |||||||||||||
| Boston butt | TW | 5.15 | 4.68 | 4.88 | 4.93 | 4.91 | 4.96 | - | - | - | - | - | - |
| CO | 5.14 | 4.63 | 5.07 | 4.58 | 5.08 | 4.98 | |||||||
| Picnic shoulder | TW | 5.11 | 5.60 | 5.44 | 4.83 | 5.63 | 4.85 | - | - | * | - | - | .17 |
| CO | 4.93 | 5.17 | 5.08 | 5.57 | 5.22 | 5.08 | |||||||
| Loin | TW | 12.96 | 12.37 | 12.71 | 12.41 | 12.27 | 12.58 | - | - | - | - | - | - |
| CO | 12.07 | 11.83 | 12.51 | 12.51 | 12.69 | 12.59 | |||||||
| Spareribs | TW | 2.20 | 2.04 | 1.99 | 1.91 | 2.10 | 2.07 | .14 | - | - | - | - | - |
| CO | 1.89 | 2.15 | 1.95 | 1.93 | 1.97 | 1.91 | |||||||
| Ham | TW | 12.49 | 12.87 | 12.68 | 12.84 | 12.40 | 12.36 | - | - | - | - | - | - |
| CO | 12.54 | 12.37 | 12.76 | 13.06 | 12.69 | 12.73 | |||||||
| Belly | TW | 9.75 | 9.52 | 9.41 | 9.36 | 8.88 | 9.53 | - | - | - | .11 | .14 | - |
| CO | 10.03 | 9.95 | 9.36 | 9.49 | 9.49 | 9.12 | |||||||
| Primal cuts (% hot carcass wt) | |||||||||||||
| Boston butt | TW | 4.57 | 4.26 | 4.33 | 4.37 | 4.24 | 4.37 | - | - | - | - | - | - |
| CO | 4.51 | 4.07 | 4.69 | 4.02 | 4.50 | 4.38 | |||||||
| Picnic shoulder | TW | 4.51 | 5.06 | 4.83 | 4.28 | 4.86 | 4.29 | - | .06 | * | .07 | - | - |
| CO | 4.32 | 4.55 | 4.72 | 4.88 | 4.60 | 4.46 | |||||||
| Loin | TW | 11.45 | 11.22 | 11.24 | 11.00 | 10.53 | 11.13 | - | - | - | - | - | - |
| CO | 10.57 | 10.40 | 11.60 | 10.99 | 11.20 | 11.08 | |||||||
| Spareribs | TW | 1.87 | 1.85 | 1.77 | 1.69 | 1.82 | 1.84 | - | - | - | - | - | .17 |
| CO | 1.65 | 1.89 | 1.89 | 1.70 | 1.73 | 1.68 | |||||||
| Ham | TW | 11.03 | 11.66 | 10.87 | 11.44 | 10.71 | 10.94 | - | - | - | - | - | - |
| CO | 10.98 | 11.39 | 11.46 | 11.68 | 11.19 | 11.21 | |||||||
| Belly | TW | 8.61 | 8.63 | 8.34 | 7.99 | 7.67 | 8.06 | .11 | - | - | .02 | - | - |
| CO | 8.80 | 8.74 | 8.68 | 8.34 | 8.36 | 8.08 | |||||||
Fat sources included corn oil (CO) and tallow (TW).
Vitamin E supplementation included α-tocopheryl-acetate (ATA) at 4 levels (11, 40, 100, and 200 ppm) and γ-tocopherol (GT) at 2 levels (40 and 100 ppm). IF, isoforms.
Linear (L) and quadratic (Q) responses are based on 4 levels of ATA.
Meat quality attributes
The water holding capacity was not affected by dietary treatments when measured by drip loss and purge loss (Table 4), whereas an increase in purge loss (linear and quadratic, P < .01) was observed with increasing retail display. As expected, belly flex was affected by dietary fat sources, but not dietary vitamin E supplementation. Bellies from pigs fed TW diets had a greater lateral distance (P < .05) and a lower vertical distance (P < .05) than those from pigs fed CO diets. Pigs fed TW diets also had a greater belly flex than pigs fed CO diets (P < .01). Bellies from pigs fed TW fat sources tended to have firmer bellies, which was anticipated since TW is higher in saturated fatty acids.
Effect of different fat sources and vitamin E isoforms on quality of fresh pork from heavy slaughter weight (150 kg) pigs.
| Parameters | Fat Source1 | Vitamin E IF2 | P Value | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ATA, ppm | GT, ppm | ATA Level3 | Fat | IF | ||||||||||
| 11 | 40 | 100 | 200 | 40 | 100 | L | Q | IF | IF×Level | IF×Fat | ||||
| Drip loss (%) at 48 h | TW | 5.99 | 4.56 | 7.40 | 5.21 | 5.85 | 7.19 | - | - | - | - | - | - | |
| CO | 7.38 | 5.20 | 5.20 | 5.36 | 6.62 | 8.97 | ||||||||
| Purge loss (%) | ||||||||||||||
| Day 7 | TW | 3.60 | 4.50 | 4.12 | 4.43 | 3.03 | 4.40 | - | - | - | - | - | - | |
| CO | 4.65 | 3.88 | 4.34 | 4.51 | 3.92 | 5.30 | ||||||||
| Day 14 | TW | 8.13 | 9.14 | 8.94 | 8.90 | 8.42 | 9.71 | - | - | - | - | - | - | |
| CO | 9.22 | 9.73 | 9.43 | 9.36 | 9.85 | 7.98 | ||||||||
| Day 30 | TW | 12.02 | 12.89 | 10.98 | 11.71 | 13.43 | 13.60 | - | - | - | .14 | - | - | |
| CO | 11.42 | 13.54 | 12.00 | 13.82 | 12.78 | 13.55 | ||||||||
| Belly flex, cm | ||||||||||||||
| Left side | Lateral | TW | 18.03 | 14.29 | 16.09 | 17.15 | 15.49 | 15.75 | - | - | <.01 | - | - | - |
| CO | 11.68 | 10.48 | 11.01 | 11.26 | 10.16 | 9.14 | ||||||||
| Vertical | TW | 29.53 | 27.94 | 27.73 | 27.94 | 28.36 | 27.18 | - | - | .04 | - | - | - | |
| CO | 31.50 | 31.05 | 29.85 | 29.13 | 32.17 | 31.24 | ||||||||
| Right side | Lateral | TW | 16.51 | 13.97 | 13.34 | 15.24 | 15.49 | 13.46 | - | .17 | <.01 | - | - | - |
| CO | 10.41 | 10.41 | 11.01 | 11.18 | 10.37 | 9.40 | ||||||||
| Vertical | TW | 29.85 | 29.46 | 30.23 | 29.72 | 30.48 | 28.15 | - | .15 | - | - | - | ||
| CO | 32.26 | 30.16 | 31.33 | 31.88 | 30.48 | 31.24 | ||||||||
| Belly angle | TW | 52.75 | 44.31 | 47.18 | 48.28 | 50.69 | 44.45 | - | - | <.01 | - | - | - | |
| CO | 31.65 | 34.26 | 34.94 | 34.08 | 33.48 | 29.52 | ||||||||
Fat sources included corn oil (CO) and tallow (TW).
Vitamin E supplementation included α-tocopheryl-acetate (ATA) at 4 levels (11, 40, 100, and 200 ppm) and γ-tocopherol (GT) at 2 levels (40 and 100 ppm). IF, isoforms.
Linear (L) and quadratic (Q) responses are based on 4 levels of ATA.
Instrumental color
Instrumental color data presented in Table 5 indicated no interactions (P > .05) between levels of dietary ATA supplementation and fat sources on color parameters, suggesting a possible lack of effect of dietary ATA on discoloration during retail display. An increase in L* (linear and quadratic; P < .01), a* (linear and quadratic; P < .01), b* (linear and quadratic; P < .01), and chroma (linear and quadratic, P < .01) were observed with an increase in display duration. Hue angle decreased (linear and quadratic; P < .01) with time.
Effect of different fat sources and vitamin E isoforms on the instrumental color of longissimus thoracis from heavy slaughter weight (150 kg) pigs.
| Parameters | Days of Retail Display | Fat Source1 | Vitamin E IF2 | P Value | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ATA, ppm | GT, ppm | ATA Level3 | Fat | IF | ||||||||||
| 11 | 40 | 100 | 200 | 40 | 100 | L | Q | IF | IF×Level | IF×Fat | ||||
| Lightness (L* value) | 1 | TW | 59.10 | 53.89 | 60.60 | 58.12 | 58.99 | 59.34 | - | - | .13 | .02 | .04 | - |
| CO | 57.01 | 55.10 | 57.31 | 56.01 | 58.96 | 59.58 | ||||||||
| 3 | TW | 60.32 | 54.74 | 61.67 | 61.47 | 57.77 | 58.59 | - | - | - | - | <.01 | - | |
| CO | 60.44 | 55.73 | 58.96 | 58.00 | 60.05 | 57.98 | ||||||||
| 5 | TW | 61.08 | 54.68 | 61.90 | 61.29 | 59.37 | 58.85 | - | - | - | .07 | <.01 | - | |
| CO | 61.10 | 55.74 | 58.64 | 59.89 | 60.67 | 58.24 | ||||||||
| 7 | TW | 60.53 | 55.16 | 62.32 | 61.38 | 59.90 | 59.23 | .06 | - | - | .15 | <.01 | - | |
| CO | 58.41 | 56.89 | 59.45 | 60.18 | 61.23 | 58.18 | ||||||||
| Redness (a* value) | 1 | TW | 8.71 | 9.57 | 8.62 | 8.86 | 9.11 | 9.15 | - | - | - | - | - | - |
| CO | 10.20 | 8.58 | 9.36 | 9.33 | 8.92 | 9.86 | ||||||||
| 3 | TW | 11.67 | 14.68 | 12.53 | 12.15 | 13.03 | 13.52 | - | - | .17 | - | .06 | - | |
| CO | 13.51 | 13.96 | 13.21 | 13.10 | 12.99 | 13.53 | ||||||||
| 5 | TW | 10.97 | 14.63 | 11.65 | 11.60 | 12.56 | 12.67 | - | - | - | .15 | .01 | - | |
| CO | 12.17 | 13.41 | 12.47 | 12.60 | 12.07 | 12.68 | ||||||||
| 7 | TW | 10.63 | 13.82 | 11.57 | 10.70 | 12.05 | 11.81 | - | - | - | .08 | .05 | - | |
| CO | 11.48 | 12.55 | 11.55 | 11.54 | 11.45 | 11.71 | ||||||||
| Yellowness (b* value) | 1 | TW | 16.26 | 14.47 | 15.72 | 15.68 | 16.14 | 16.57 | - | - | - | <.01 | - | - |
| CO | 16.74 | 14.14 | 15.62 | 15.62 | 16.18 | 16.71 | ||||||||
| 3 | TW | 17.92 | 18.46 | 17.86 | 17.66 | 18.19 | 18.30 | - | - | - | - | .04 | - | |
| CO | 18.03 | 18.59 | 17.57 | 18.17 | 17.88 | 18.10 | ||||||||
| 5 | TW | 17.58 | 18.05 | 17.35 | 17.39 | 17.42 | 17.81 | - | - | - | - | - | - | |
| CO | 17.67 | 18.05 | 17.67 | 17.99 | 18.11 | 17.74 | ||||||||
| 7 | TW | 17.08 | 17.79 | 17.18 | 16.80 | 17.12 | 17.29 | - | - | - | - | - | .17 | |
| CO | 17.10 | 17.47 | 17.03 | 17.24 | 17.74 | 17.42 | ||||||||
| Hue angle | 1 | TW | 1.06 | 0.99 | 1.05 | 1.06 | 1.02 | 1.07 | - | - | .15 | .03 | .08 | - |
| CO | 1.02 | 1.03 | 1.04 | 1.04 | 1.07 | 1.04 | ||||||||
| 3 | TW | 0.99 | 0.89 | 0.97 | 0.97 | 0.94 | 0.94 | - | - | - | - | .02 | - | |
| CO | 0.94 | 0.93 | 0.94 | 0.97 | 0.96 | 0.93 | ||||||||
| 5 | TW | 1.01 | 0.90 | 0.98 | 0.98 | 0.95 | 0.95 | - | - | - | - | .02 | - | |
| CO | 0.97 | 0.93 | 0.96 | 0.96 | 0.98 | 0.95 | ||||||||
| 7 | TW | 1.02 | 0.92 | 1.01 | 1.01 | 0.96 | 0.97 | - | - | - | - | .05 | - | |
| CO | 0.98 | 0.95 | 0.98 | 0.98 | 1.00 | 0.98 | ||||||||
| Chroma | 1 | TW | 18.48 | 17.35 | 17.95 | 18.03 | 18.19 | 18.93 | - | - | - | .02 | - | - |
| CO | 19.62 | 16.54 | 18.22 | 17.59 | 18.48 | 19.41 | ||||||||
| 3 | TW | 21.40 | 23.86 | 21.99 | 21.46 | 22.07 | 22.77 | - | - | - | - | <.01 | - | |
| CO | 22.84 | 23.26 | 21.67 | 22.42 | 21.76 | 22.61 | ||||||||
| 5 | TW | 21.02 | 23.00 | 20.63 | 20.93 | 21.49 | 21.88 | - | - | - | - | .03 | - | |
| CO | 20.98 | 22.49 | 21.65 | 21.99 | 21.51 | 21.83 | ||||||||
| 7 | TW | 20.15 | 22.43 | 20.32 | 19.95 | 20.97 | 20.97 | - | - | - | - | .06 | - | |
| CO | 20.12 | 21.51 | 20.60 | 20.77 | 21.13 | 21.10 | ||||||||
Fat sources included corn oil (CO) and tallow (TW).
Vitamin E supplementation included α-tocopheryl-acetate (ATA) at 4 levels (11, 40, 100, and 200 ppm) and γ-tocopherol (GT) at 2 levels (40 and 100 ppm). IF, isoforms.
Linear (L) and quadratic (Q) responses are based on 4 levels of ATA.
Interactions between vitamin E isoforms and their levels were observed on L* (day 1, P = .04; day 3, P < .01; day 5, P < .01; day 7, P < .01), a* (day 3, P = .06; day 3, P = .01; day 7, P = .05), b* (day 3, P = .04), hue angle (day 1, P = .08; day 3, P = .02; day 5, P = .02; day 7, P = .05), and chroma (day 3, P < .01; day 5, P = .03; day 7, P = .06). Additionally, differences between the 2 isoforms were detected on L* (day 1, P = .02; day 3, P = .07), b* (day 1, P < .01), hue angle (day 1, P = .03), and chroma (day 1, P = .02). Interactions between display time and isoforms of vitamin E (P < .01) were observed for b* and chroma. No interactions (P > .05) between isoforms and fat sources were observed on meat color during the retail storage.
Lipid oxidation
The results of lipid oxidation, measured as TBARS, are provided in Table 6. No interactions between fat sources and dietary vitamin E treatments (isoforms or levels) were observed in lipid oxidation. While levels of ATA did not affect lipid oxidation from day 1 to day 5, increasing dietary ATA decreased TBARS at day 7 (linear, P < .01). TBARS content increased with time (linear and quadratic, P < .01), and an interaction between storage time and levels of ATA was observed (P < .05). Further comparison indicated that the TBARS in the loins from pigs fed 11 ppm ATA increased in a greater (P < .05) rate compared to those from pigs fed 40, 100, and 200 ppm ATA. This observation indicated that the lipid stability in pork loins improved (P < .01) when dietary ATA level was at or above 40 ppm. No effect of isoform was observed on lipid oxidation in this study. Dietary fat sources affected (P < .05) lipid oxidation from day 1 to day 7. The increase in lipid oxidation with time was affected by fat sources as indicated by the interaction between storage time and fat sources (P < .01). Furthermore, the TBARS content in loins from pigs fed CO diets increased at a greater (P < .05) rate compared to those from pigs fed TW diets.
Effect of different fat sources and vitamin E isoforms on lipid oxidation measured in pork longissimus thoracis from heavy slaughter weight (150 kg) pigs.
| Parameter | Days of Retail Display | Fat Source1 | Vitamin E IF2 | P Value | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ATA, ppm | GT, ppm | ATA Level3 | Fat | IF | ||||||||||
| 11 | 40 | 100 | 200 | 40 | 100 | L | Q | IF | IF×Level | IF×Fat | ||||
| TBARS4 | 1 | TW | 0.28 | 0.23 | 0.22 | 0.22 | 0.26 | 0.25 | - | - | .02 | - | - | .18 |
| CO | 0.26 | 0.29 | 0.29 | 0.29 | 0.27 | 0.28 | ||||||||
| 3 | TW | 0.32 | 0.31 | 0.29 | 0.30 | 0.32 | 0.30 | - | - | <.01 | .18 | .17 | - | |
| CO | 0.37 | 0.33 | 0.36 | 0.34 | 0.39 | 0.35 | ||||||||
| 5 | TW | 0.41 | 0.35 | 0.33 | 0.39 | 0.34 | 0.33 | .15 | .12 | .09 | - | - | - | |
| CO | 0.44 | 0.39 | 0.43 | 0.37 | 0.41 | 0.46 | ||||||||
| 7 | TW | 0.74 | 0.59 | 0.53 | 0.56 | 0.63 | 0.64 | <.01 | .15 | <.01 | - | - | .07 | |
| CO | 0.87 | 0.75 | 0.78 | 0.65 | 0.61 | 0.73 | ||||||||
Fat sources included corn oil (CO) and tallow (TW).
Vitamin E supplementation included α-tocopheryl-acetate (ATA) at 4 levels (11, 40, 100, and 200 ppm) and γ-tocopherol (GT) at 2 levels (40 and 100 ppm). IF, isoforms.
Linear (L) and quadratic (Q) responses are based on 4 levels of ATA.
TBARS, thiobarbituric acid reactive substances.
Discussion
Carcass traits and primal cuts
The observed increase in pig slaughter weight is consistent with the positive effects of vitamin E levels on daily gain reported previously (Asghar et al., 1991). Similarly, Boler et al. (2009) documented an increase in live weight in pigs fed 70 mg/kg natural vitamin E compared to 40 mg/kg natural vitamin E and 200 mg/kg synthetic vitamin E. Wang et al. (2022) evaluated the effects of dietary vitamin E (11 ppm and 200 ppm) and fat supplementation (corn starch, TW, distiller’s CO, and coconut oil) in growing-finishing swine fed to a heavy slaughter weight of 150 kg and observed that increasing dietary vitamin E from 11 ppm to 200 ppm did not influence hot carcass weight, cold carcass weight, shrink loss, carcass length, back fat depth, and loin muscle dimensions. This observation agreed with the findings of the present study. However, these authors reported similar slaughter weight with the increase of vitamin E, contrasting with the present results. On the contrary, Corino et al. (1999) demonstrated that dietary supplementation of vitamin E at 200 mg/kg increased the hot carcass weight of pigs compared to diets containing 25 mg/kg of vitamin E.
Wang et al. (2012) investigated the carcass and meat quality of pigs supplemented with different corn-dried distillers’ grains with solubles and vitamin E (10 IU/kg or 210 IU/kg) supplemented diets and reported similar slaughter weight, carcass weight, dressing percentage, back fat thickness, and loineye area. Additionally, Jin et al. (2018) investigated the effects of pioglitazone hydrochloride and vitamin E on the meat quality of finishing pigs and reported that vitamin E supplementation had no effect on live weight, carcass weight, dressing percentage, or backfat thickness. Furthermore, Boler et al. (2009) reported that the supplementation of diets with different concentrations of vitamin E did not influence the carcass characteristics of growing-finishing pigs. Huang et al. (2019) evaluated the effect of vitamin E supplementation on growth performance, serum metabolites, carcass characteristics of finisher pigs, and physical characteristics of pork, and the study reported that the supplementation of 220 IU/kg vitamin E resulted in greater pork marbling score compared to 11 IU/kg but exerted no effects on hot carcass weight, dressing percentage, loin muscle area, and muscling score.
With respect to fat source, Davis et al. (2015) evaluated the effect of adding supplemental TW to diets containing 30% distillers dried grains with solubles on growth performance, carcass characteristics, and pork fat quality in growing-finishing pigs and reported that pigs fed 5% TW had greater backfat depth than pigs fed no TW, which disagreed with the present results.
Muscle pH
Wang et al. (2022) also documented an increase of 45-min pH and ΔpH with the increase of dietary vitamin E from 11 ppm to 200 ppm, although there was no change in the ultimate carcass pH at 24 h. A low muscle pH in the initial stages of postmortem is known to induce pale, soft, and exudative (PSE) conditions in pigs (Kim et al., 2016). In this perspective, increasing the levels of vitamin E may be beneficial to minimize the occurrence of PSE in pork.
On the contrary, Huang et al. (2019) reported that dietary treatments had no clear effect on ultimate loin pH in their investigations on the effects of flaxseed oil, animal fat, and vitamin E on the characteristics of finisher pigs. Guo et al. (2006) evaluated the effects of dietary vitamin E (40 IU/kg and 200 IU/kg) and fat supplementation (normal corn, high oil corn, high oil corn plus added beef TW) on pork quality and reported that adding fat or vitamin E did not affect the ultimate pH of longissimus muscle. Wang et al. (2012) documented similar 45-min pH and 24-h pH in pork longissimus muscle from pigs fed corn-dried distillers’ grains with solubles and 10 IU/kg or 210 IU/kg of vitamin E supplemented diets.
Dressing percentage and belly depth
Wang et al. (2022) investigated the effect of dietary vitamin E (11 ppm and 200 ppm) and fat supplementation (corn starch, TW, distiller’s CO, and coconut oil) on carcass quality of heavy pigs and documented that the pigs fed coconut oil exhibited greater belly depth compared with their counterparts fed corn starch, TW, and distiller’s CO. These authors (Wang et al., 2022) reported that increasing dietary vitamin E levels from 11 ppm to 200 ppm tended to increase the relative yield of picnic shoulder, whereas fat sources (corn starch, TW, distiller’s CO, and coconut oil) did not influence the picnic shoulder’s yield or absolute weight. Huang et al. (2019) reported that increasing dietary lipids (0% or 1% flaxseed oil + 1%, 3%, or 5% poultry fat) increased pork belly width and thickness. Pigs fed diets with no lipid supplementation tended to have greater belly length and less width than those fed diets supplemented with 1% flaxseed oil plus 1%, 3%, or 5% poultry fat. Dietary treatments had no effects on belly firmness.
Water holding capacity
In agreement with our results, Wang et al. (2022) documented that water holding capacity (measured by drip loss and purge loss) was not affected by vitamin E supplementation (11 ppm or 200 ppm) and that purge loss increased with the increase in storage time. Boler et al. (2009) reported no effect of vitamin E concentrations on drip loss of pork carcasses. On the contrary, other studies reported a decrease in drip loss with an increase in dietary vitamin E levels. Guo et al. (2006) reported that longissimus muscle from pigs fed 400 IU/kg of vitamin E exhibited lower drip loss than those from pigs fed 40 IU/kg. Wang et al. (2012) reported a decrease in drip loss in pork longissimus muscle with an increase in vitamin E concentration (from 10–210 IU/kg).
Belly firmness attributes
Belly firmness is positively correlated with saturated fatty acid levels in swine diets (Rentfrow et al., 2003; Kellner et al., 2014). Feeding pigs with diets high in unsaturated fatty acids could increase the deposition of unsaturated fatty acids in adipose tissues (Whitney et al., 2006; Wang et al., 2012; Kellner et al., 2014), reducing belly firmness. In agreement with the results of the present study, Wang et al. (2022) documented that the pigs fed distiller’s CO exhibited lower lateral distance and belly angle but a greater vertical distance than the pigs fed TW. Additionally, Kellner et al., (2014) documented that the pigs fed TW produced firmer bellies (lower belly firmness score) than their counterparts fed CO. In support of our findings, Huang et al. (2019) and Wang et al. (2022) reported no influence of vitamin E (11 IU/kg or 200 IU/kg) on overall fresh pork belly firmness attributes.
Instrumental color
In agreement with our findings, previous investigations observed no effect of vitamin E on color stability of ground pork (Houben et al., 1998; Phillips et al., 2001) as well as longissimus (Cannon et al., 1996; Jensen et al., 1997; Jin et al., 2018; Huang et al. 2019; Wang et al., 2022) and psoas major (Jensen et al., 1997) muscles from pigs fed with dietary vitamin E. On the contrary, Monahan et al. (1994) reported greater redness in longissimus muscle from pigs fed ATA (200 mg/kg feed) than those from pigs fed the basal level (10 mg/kg feed). Lanari et al. (1995) reported greater redness in longissimus lumborum muscles from pigs fed higher levels (187–207 mg/kg feed) of vitamin E than those from pigs fed lower levels (13 mg/kg feed and nonsupplemented).
The lack of response of pork color to dietary vitamin E supplementation could be attributed to the low susceptibility of pork myoglobin to oxidation induced by lipid oxidation. Lipid oxidation generates a variety of secondary oxidation products, such as 4-hydroxynonenal, which is capable of adducting histidine residues in myoglobin and subsequently accelerate oxidation of the heme protein. Pork myoglobin is less susceptible to adduction by 4-hydroxynonenal than beef myoglobin (Suman et al., 2007). Therefore, color stability of fresh pork is affected minimally by the presence of prooxidants (e.g., lipid oxidation products) and antioxidants (e.g., vitamin E) during retail storage (Suman et al., 2006).
Lipid oxidation
In concurrence with the results of the present study, previous investigations documented the effectiveness of vitamin E to delay lipid oxidation in pork longissimus (Lanari et al., 1995; Cannon et al., 1996; Jensen et al., 1997; Zhu et al., 2022; Bottegal et al., 2025) and psoas major (Jensen et al., 1997) muscles. Additionally, dietary supplementation of vitamin E decreased lipid oxidation in ground pork patties (Houben et al., 1998; Phillips et al., 2001). Guo et al. (2006) evaluated the effects of dietary vitamin E (40 IU/kg and 200 IU/kg) and fat supplementation (normal corn, high oil corn, high oil corn plus added beef TW) on pork quality and reported that the increase of vitamin E levels decreased lipid oxidation in ground pork patties from the fat-supplemented animals. Wang et al. (2012) investigated meat quality of pigs fed different concentrations of corn-dried distillers’ grains with soluble and vitamin E (10 IU/kg or 210 IU/kg) and reported a decrease in lipid oxidation with the increase of vitamin E concentration during storage.
The observed decrease in lipid oxidation with an increase in vitamin E levels could be attributed to vitamin E’s antioxidant effect in skeletal muscle matrix (Faustman et al., 2010). The free radical scavenging ability of vitamin E protects polyunsaturated fatty acids and inhibits the propagation of lipid peroxidation (Choe and Min, 2006; Ralla et al., 2024). The increased lipid oxidation in chops from pigs fed CO diet could be attributed to the greater content of polyunsaturated fatty acids in CO compared to the TW (Wang et al., 2022). Increased levels of highly oxidizable polyunsaturated fatty acids in the diet lead to an increase of polyunsaturated fatty acids in skeletal muscles, consequently decreasing the lipid stability in postmortem muscles.
Conclusions
The results of the study demonstrated the interaction of dietary fat sources and vitamin E supplementation on carcass characteristics, primal cuts, meat quality, and oxidative stability of pigs grown to 150 kg. Increasing dietary levels of ATA had beneficial impacts on carcass traits. Compared to dietary CO, pigs fed dietary TW had a greater belly depth and belly angle that could increase bacon slicing yield. Feeding GT at 40 ppm, compared to 40 ppm ATA, decreased redness and increased lightness of loin chops. In contrast, feeding GT at 100 ppm increased darkness and redness during retail display than 100 ppm ATA. Loin chops from pigs fed TW displayed greater lightness and yellowness during retail display compared to those from pigs fed CO. Supplementing GT at 100 ppm could be explored as an approach to improve color of loins from heavy slaughter weight pigs. Additionally, fats with increased levels of saturated fatty acids, such as TW, can be used as dietary strategy for firmer and more desirable pork bellies from heavy slaughter weight pigs.
Conflict of Interest
The authors declare no conflicts of interest.
Acknowledgments
This work was supported by the National Pork Board, Fats and Proteins Research Foundation, and DSM Nutritional Products.
Author Contributions
Marlee Kelley: data curation, formal analysis, and writing—original draft; Ding Wang: data curation; Gregg Rentfrow: conceptualization, funding acquisition, investigation, methodology, resources, supervision, and writing—original draft; Merlin Lindemann: conceptualization, funding acquisition, investigation, methodology, resources, supervision, and writing—review and editing; Ana Paula Salim: writing—original draft, and writing—review and editing; and Surendranath P. Suman: investigation, methodology, supervision, writing—original draft, and writing—review and editing.
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