Supplementing antioxidants to pigs fed diets high in oxidants: II. Effects on carcass characteristics, meat quality, and fatty acid profile1

Abstract

The study was conducted to determine effects of dietary supplementation with a blend of antioxidants (ethoxyquin and propyl gallate) on carcass characteristics, meat quality, and fatty acid profile in finishing pigs fed a diet high in oxidants. A total of 100 crossbred barrows (10.9±1.4 kg BW, 36±2 d of age) were randomly allotted to 5 diet treatments (5 replicate pens per treatment, 4 pigs per pen). Treatments included: 1) HO: high oxidant diet containing 5% oxidized soy oil and 10% PUFA source which contributed 5.56% crude fat and 2.05% docosahexanoic acid (DHA) to the diet; 2) VE: the HO diet with 11 IU/kg of added vitamin E; 3) AOX: the HO diet with antioxidant blend (135 mg/kg); 4) VE+AOX: the HO diet with both vitamin E and antioxidant blend; and 5) SC: a standard corn-soy control diet with nonoxidized oil and no PUFA source. The trial lasted for 118 d; on d 83, the HO diet pigs were switched to the SC diet due to very poor health. From that point, the VE pigs displayed the poorest performance. On d 118, 2 pigs from each pen were harvested for sampling. Compared to pigs fed SC diet, the HO and VE pigs (P<0.05) showed lighter carcass weight, less back fat, less lean body mass, and smaller loin eye area. In addition, the VE pigs had decreased dressing percentage than the AOX and VE+AOX pigs (65.7 vs. 75.3 and 74.2%). Compared to the SC pigs, greater moisture percentage (74.7 vs. 77.4%) and less extractable lipid content (2.43 vs. 0.95%) were found in VE fed pigs (P<0.05). Drip loss of loin muscle in VE pigs was less than SC pigs (0.46 vs. 3.98%, P=0.02), which was associated with a trend for a greater 24-h muscle pH (5.74 vs. 5.54, P=0.07). The antioxidant blend addition in the high oxidant diet attenuated all of these effects to levels similar to SC (P>0.05), except a* value (redness) and belly firmness. Visible yellow coloration of backfat and lipofuscin in HO and VE pigs was observed at harvest at d 118. The high oxidant diet resulted in greater concentration of DHA in backfat (P<0.001); switching the diet on d 83 resulted in HO pigs having a similar fatty acid profile to SC at d 118 pigs. Vitamin E concentration in plasma and muscle was greater in HO and SC than VE, AOX, and VE+AOX on d 118. Feeding the high oxidant diet caused a series of changes in carcass characteristics and meat quality. Addition of antioxidant blend attenuated many of these, whereas the protective effects of supplemental vitamin E at 11 IU/kg were minimal during the finisher phase of the study.

Dietary supplementation of pyrroloquinoline quinone disodium protects against oxidative stress and liver damage in laying hens fed an oxidized sunflower oil-added diet

“…In agreement with some previous studies in pigs (Lu et al, 2014b), an increment of liver weight and liver to BW ratio induced by oxidized oil was apparent in the present study. This increase resulted from the elevated absolute weight of the livers because dietary oxidized sunflower oil did not produce a significant effect on BW.…”

“…A number of studies have shown that domestic animal production performance was depressed by dietary addition of oxidized lipids (Yue et al, 2011;Fontagné-Dicharry et al, 2014;Lu et al, 2014a and2014b;Rosero et al, 2015). The depression partly resulted from a reduced palatability of the rancid feed, leading to a lower feed intake .…”

Effect of dietary selenium source (organic vs. mineral) and muscle pH on meat quality characteristics of pigs

“…) and also a trend toward higher muscle pH at 24 h postmortem (5.7 vs. 5.5) (Lu et al. ); however, there is no further information on the possible interaction effects with the selenium source.…”

“…Moreover, in our study, muscle pH did not affect vitamin E concentration (Table 4). A direct association between muscle vitamin E and lower drip loss has been described (Ashgar et al 1991) and also a trend toward higher muscle pH at 24 h postmortem (5.7 vs. 5.5) (Lu et al 2014); however, there is no further information on the possible interaction effects with the selenium source.…”

Supplementing antioxidants to pigs fed diets high in oxidants: I. Effects on growth performance, liver function, and oxidative status1

“…The SC diet was formulated to approximate a corn-soybeanbased diet typical of North American production conditions. Analyzed fatty acid profiles of the experimental diets and commercial PUFA source are presented in a companion paper (Lu et al, 2014). All experimental diets were fed on an ad libitum basis throughout the experiment.…”