Effects of choice white grease and soybean oil on growth performance, carcass characteristics, and carcass fat quality of growing-finishing pigs

Abstract

A total of 144 barrows and gilts (initial BW = 44 kg) were used in an 82-d experiment to evaluate the effects of dietary fat source and duration of feeding fat on growth performance, carcass characteristics, and carcass fat quality. Dietary treatments were a corn-soybean meal control diet with no added fat and a 2 × 4 factorial arrangement of treatments with 5% choice white grease (CWG) or soybean oil (SBO) fed from d 0 to 26, 54, 68, or 82. At the conclusion of the study (d 82), pigs were slaughtered, carcass characteristics were measured, and backfat and jowl fat samples were collected. Fatty acid analysis was performed, and iodine value (IV) was calculated for all backfat and jowl fat samples. Pigs fed SBO tended to have increased (P = 0.07) ADG compared with pigs fed CWG. For pigs fed SBO, increasing feeding duration increased (quadratic, P < 0.01) ADG and G:F. For pigs fed CWG, increasing feeding duration improved (quadratic, P < 0.01) G:F. For pigs fed SBO or CWG, increasing feeding duration increased carcass yield (quadratic, P < 0.04) and HCW (quadratic, P < 0.02). Dietary fat source and feeding duration did not affect backfat depth, loin depth, or lean percentage. As expected, barrows had greater ADG and ADFI (P < 0.01) and poorer G:F (P = 0.03) than gilts. Barrows also had greater last-rib (P = 0.04) and 10th-rib backfat (P < 0.01) and reduced loin depth and lean percentage (P < 0.01) compared with gilts. Increasing feeding duration of CWG or SBO increased (P < 0.10) C18:2n-6, PUFA, PUFA:SFA ratio, and IV in jowl fat and backfat. Pigs fed SBO had greater (P < 0.01) C18:2n-6, PUFA, PUFA:SFA ratio, and IV but decreased (P < 0.01) C18:1 cis-9, C16:0, SFA, and MUFA concentrations compared with pigs fed CWG in jowl fat and backfat. Barrows had decreased (P = 0.03) IV in jowl fat and backfat compared with gilts. In summary, adding SBO or CWG increased the amount of unsaturated fat deposited. Increasing feeding duration of dietary fat increases the amount of unsaturated fatty acids, which leads to softer carcass fat.

Influence of dietary fat source and feeding duration on finishing pig growth performance, carcass composition, and fat quality1,2

“…Numerous studies have shown that adding fat to swine diets in some or all of the finishing phase im proves feed efficiency when compared with pigs fed a diet without fat (Weber et al, 2006;Benz et al, 2011a;Kellner et al, 2014). The increase in ADG from d 0 to 42 for pigs fed added fat in the current study agrees with (Continued) results from Campbell and Taverner (1988) and De la Llata et al (2001), indicating pigs were in an energy dependent state for this period of growth as described by Pettigrew and Esnaola (2001).…”

“…However, a 40 and 19d withdrawal still maintained a difference of 5.5 and 6.4 percentage units for C18:2 as well as 5.5 and 8.7 g/100 g, respectively, for jowl fat when compared with pigs not fed a diet with added fat. Benz et al (2011a) also reported that with an extended withdrawal period, a greater reduction in C18:2, PUFA, and IV can be observed in backfat and jowl fat when feeding 5% soybean oil. We observed similar responses in backfat as a 42d withdrawal from pigs previously fed a 4% soybean oil diet resulted in 6.94 and 8.13 per centage units decrease in C18:2 and PUFA, respective ly, and also lowered IV by 11.55 g/100 g for backfat.…”

“…It has been suggested that removing unsatu rated fat sources in late finishing diets could alleviate some of the negative effects of these fat sources on carcass and fat quality (Benz et al, 2011a). Limiting the duration of feeding unsaturated fats and substi tuting a saturated fat, such as beef tallow, in late fin ishing has shown promise for positively affecting IV (Browne et al, 2013a;Kellner et al, 2014).…”

Effects of supplementary vegetable and animal fats on the slaughter values of fatteners, meat quality, and fatty acid profile in pigs

“…In the backfat of both groups the PUFA n-6/n-3 ratio amounted to 1.7, whereas in the control group it was 5.56 (Grześkowiak 1 diets: A = 2.5% rapeseed oil and 1% linseed oil, B = 1% rapeseed oil, 2% fish oil + 0.5% lard, C = 2.5% linseed oil and 1% fish oil, D = 2.3% linseed oil, 1% rapeseed oil + 0.2% lard 2 all saturated fatty acids 3 all monounsaturated fatty acids 4 all polyunsaturated fatty acids 5 dietary fatty acids having undesirable hypercholesterolemic effect in humans (C14:0 + C16:0) 6 ΣPUFA + MUFA 7 dietary fatty acids having desirable neutral of hypocholesterolemic effect in humans (UFA + C18:0) X-Z different letters within a row indicate significant differences P ≤ 0.01 (*P < 0.05) x-z different letters within a row indicate significant differences P ≤ 0.05 (**P < 0.01) ns = nonsignificant difference Benz et al (2011) used in the diet a 5% supplement of soybean oil in a period of 25 to 82 days of the pigs' life. In the backfat of animals, the total content of PUFA acids increased from 17.2% (on day 26 of feeding) to 29.6% (on day 82).…”

“…Worse results in the modification of the fatty acids profile were stated in the case when olive oil (Nuernberg et al, 2005) or soybean oil (Benz et al, 2011) was used. According to Mitsumoto et al (1991) and Leksanich et al (1997), too high amount of polyunsaturated fatty acids in the intramuscular and depot fat affects the fat consistency (soft, sticky), worsens the taste, and also durability.…”