Feeding high oleic soybean oil to growing-finishing pigs: effects on growth performance, carcass characteristics, loin quality, and bacon attributes

The objective of this project was to evaluate the effects of feeding high oleic soybean oil (HOSO) to growing-finishing pigs on growth performance, carcass characteristics and yield, loin quality and shelf life, and fat and belly quality. A total of 288 pigs raised in two equal blocks were assigned to 1 of 4 diets containing either 25% dried distillers’ grains with solubles (DDGS), 2% high oleic soybean oil (HOSO2), 4% high oleic soybean oil (HOSO4), and 6% high oleic soybean oil (HOSO6). Pigs were housed 4 per pen and were fed for 98 d using a 3-phase feeding system. Pigs were individually weighed and feed intake was recorded throughout the trial to calculate average daily feed intake (ADFI) and gain to feed ratio (G:F). A total of 144 pigs were transported to the University of Illinois Meat Science Laboratory and fabricated into primal and subprimal cuts to calculate carcass cutting yields. Fabricated loins were evaluated for fresh loin quality 1 d post-mortem including instrumental color, visual color, marbling, and firmness, pH, and drip loss. Following evaluation, loins were cut into loin chops for further analysis including Warner-Bratzler shear force, proximate analysis, trained taste panels, simulated retail display, and thiobarbituric acid reactive substance (TBARS). Fabricated bellies were collected for evaluation of fresh belly characteristics including length, width, thickness, and flop distance. Additionally, adipose tissue samples were collected for fatty acid analysis. Bellies were processed into bacon at the University of Illinois Meat Science Laboratory and bacon characteristics were collected. There were overall differences in growth performance, as pigs fed the DDGS treatment had a greater (P ≤ 0.01) overall ADFI compared to pigs fed in any HOSO group. Pigs fed the HOSO6 diet had greater (P ≤ 0.03) overall G:F than pigs fed DDGS or HOSO2 diets, but did not differ (P > 0.05) from pigs fed HOSO4. Furthermore, there were differences in carcass traits, as hot carcass weight (HCW) was increased (P ≤ 0.03) in pigs fed the HOSO6 diet compared to pigs fed the DDGS or HOSO2 diets while pigs fed HOSO4 did not differ (P > 0.05) from either extreme. Additionally, pigs fed HOSO4 or HOSO6 produced fatter (P ≤ 0.01) carcasses with a reduced (P ≤ 0.01) standardized fat-free lean compared to pigs fed DDGS or HOSO2. There were minimal differences (P ≤ 0.05) in primal weights expressed as a percentage of chilled side including bone-in Boston butt, trimmed loin, and trimmed ham with weights decreasing with the increasing inclusion of HOSO in the swine diets. There were no differences (P > 0.05) in loin pH, visual color, subjective firmness, lightness (L*), yellowness (b*), drip loss, WBSF, or cook loss between dietary treatments. However, visual marbling was increased (P ≤ 0.01) in loin chops from pigs fed HOSO4 or HOSO6 treatments compared with chops from pigs fed the DDGS dietary treatment. Loin chops were more red (a*) (P ≤ 0.01) from pigs fed HOSO diets when compared with pigs fed DDGS. Additionally, extractable lipid was decreased (P ≤ 0.01) in fresh loin chops from pigs fed DDGS and HOSO2 diets compared with pigs fed HOSO6. Furthermore, there were no differences (P ≥ 0.75) in tenderness, juiciness, or flavor measured by trained panelist for loin chops from different dietary treatments. For the simulated retail display, loin chops increased (P ≤ 0.01) in lightness and discoloration scores with storage time while there was a decrease (P ≤ 0.01) in redness, yellowness, and ratio of 630nm/580nm. There was a difference (P ≤ 0.01) between diets for lightness, redness, yellowness, and ratio of 630nm/580nm overall, but within each day of retail display, dietary treatments were not different (P ≥ 0.05). Initial and final TBARS did not differ between dietary treatments (P ≥ 0.92). Pork fatty acid composition was altered by dietary HOSO inclusion, as the percentage of oleic acid, or C18:1n-9, was least (P ≤ 0.01) in pigs fed DDGS (41.31%) and increased with increasing levels of HOSO inclusion (HOSO2 47.6%, HOSO4 50.7%, HOSO 6 54.4%). Inversely, pigs fed DDGS (33.47%) had (P ≤ 0.01) the greatest concentration of palmitic acid, C16:0, and was decreased with increasing levels of HOSO inclusion (HOSO2 31.7%, HOSO4 29.4%, HOSO 6 26.0%). Furthermore, pigs fed the DDGS diet had a greater (P ≤ 0.01) concentration of linoleic acid, or C18:2n-6, compared to pigs fed any of the HOSO diets. Pigs fed DDGS produced wider (P ≤ 0.03) bellies with reduced (P ≤ 0.04) belly thickness and flop distance compared to pigs fed the any of the HOSO diets. Pigs fed the DDGS diet also had an increase (P ≤ 0.01) in pump uptake compared to pigs fed the HOSO diets; however, there were no differences (P = 0.11) in cook yield. Overall, feeding HOSO as a dietary feed ingredient to pigs improved growth performance parameters including ADFI and G:F, and resulted in fatter, heavier carcasses. Furthermore, there were no negative implications on pork quality for pigs fed HOSO and increases in marbling and redness may suggest potential improvements in loin appearance. Finally, feeding HOSO to pigs resulted in a successful manipulation of pork fatty acid composition with bellies having increased oleic acid percentage and decreased palmitic acid and linoleic acid percentages as graded levels of HOSO were added to the diet. As a result, pigs fed the HOSO diets produced thicker bellies with greater flop distances compared to pigs fed DDGS. Ultimately, feeding HOSO as a dietary feed ingredient for pigs has the potential to improve specific growth performance, loin quality, and fresh belly characteristics.U of I OnlyAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD syste