Influence of feeding thermally peroxidized lipids on growth performance, lipid digestibility, and oxidative status in nursery pigs

Influence of feeding thermally peroxidized lipids on the performance of growing pigs

Feeding pigs lipids containing high levels of lipid oxidation products (LOP) has been shown to reduce growth performance, but data is lacking on quantitative relationships between LOP and pig growth, feed intake, and feed efficiency. Four experiments (EXP) were conducted using soybean oil (SO) in EXP 1, 2, and 3, as well as SO, choice white grease and palm oil (PO) in EXP 4, to evaluate the impact of feeding diets containing different amounts of LOP on pig performance. Lipid peroxidation was carried out using variable heating temperatures and durations to generate lipids with a broad range of peroxide (PV, mEq) and anisidine value (AnV, unitless). Lipids were added to the diets at 10%, 10%, 8%, and 7.5% for EXP 1, 2, 3, and 4, respectively, with dietary PV and AnV calculated using lipid peroxidation concentrations of PV and AnV times the dietary lipid inclusion rate. Within each experiment, pig performance (6.2 to 13.4 kg, EXP 1; 13.5 to 23.7 kg, EXP 2; 20.3 to 36.9 kg, EXP 3; 29.6 to 44.1 kg, EXP 4) was affected differently depending on dietary PV and AnV concentrations. Using the control-fed pigs within each experiment as a baseline of 100%, correlations of pooled relative pig performance data (dependent variables of ADG, ADFI, and GF) from EXP 1, 2, 3, and 4 with their respective dietary LOP values (independent variables of dietary PV and AnV due their ability to be measured commercially) resulted in significant (P ≤ 0.01) regression equations for relative ADG [ADG, % = 101.2 - [(0.321 × PV) + (1.019 × AnV)], R2 = 0.81], ADFI [ADFI, % = 100.8 - [(0.320 × PV) + (0.629 × AnV)], R2 = 0.68], and GF [GF, % = 101.3 - [(0.016 × PV) + (0.525 × AnV)], R2 = 0.70], albeit PV was not a significant regression coefficient in the GF model (P = 0.90). This data shows that the values of primary and secondary LOP (i.e., PV and AnV, respectively) could be effectively used in predicting the effect of feeding oxidized lipids on growth, feed intake, and feed efficiency in growing pigs.

Feeding nursery pigs diets containing peroxidized soybean oil has minimal effects on oxidative status but dramatically reduces serum vitamin E concentrations

A subgroup of pigs from two experiments (EXP) was selected to evaluate the impact of pigs fed diets containing peroxidized soybean oil (SO) on plasma-based measures of oxidative stress and vitamin E. Pigs were fed diets containing SO that was either unprocessed (23 °C; peroxide value (PV) of 3 meq/kg and an anisidine value of 4) or thermally processed at 135 °C for 42 h (PV of 30 meq/kg and an anisidine value of 501). The corn-soybean meal-based diets contained either 10% SO (EXP 1) or 8% SO (EXP 2). Pigs were fed the experimental diets for 22 d (EXP 1, 13.5 to 24.0 kg, 2 pigs/pen) or 27 d (EXP 2, 21.3 to 37.5 kg, 1 pig/pen), each with 10 replications per dietary treatment. Pigs fed diets containing the peroxidized SO had reduced ADG, ADFI, and GF compared to pigs fed diets containing the unheated SO (P ≤ 0.01). Pigs fed diets containing peroxidized SO had increased plasma concentrations of F2-isoprostanes and reactive oxygen metabolites compared to pigs fed diets containing unheated SO (P ≤ 0.01). In contrast, plasma thiobarbituric acid reactive substances concentrations tended to decrease in pigs fed diets containing peroxidized SO compared to pigs fed diets containing unheated SO (P = 0.10). There was no apparent effect of pigs consuming diets containing peroxidized SO on plasma antioxidant adsorbent capacity or an oxidative stress index (P ≥ 0.19). Pigs fed diets containing peroxidized SO resulted in a reduction in plasma vitamin E compared to pigs fed diets containing unheated SO (P ≤ 0.01). Results indicate that adding SO that has been thermally processed thereby containing high concentrations of aldehydes resulted in inconsistent changes of markers of oxidative stress, but dramatically reduced plasma vitamin E concentrations.

Growth performance, visceral organ weights, and gut health of weaned pigs fed diets with different dietary fiber solubility and lipid sources

The objective of this study was to determine the interactive effects of dietary fiber solubility and lipid source on growth performance, visceral organ weights, gut histology, and gut microbiota composition of weaned pigs. A total of 280 nursery pigs [initial body weight (BW) = 6.84 kg] weaned at 21 d were housed in 40 pens (7 pigs/pen). The pigs were fed four diets (10 pens/diet) in a randomized complete block design in two phases: Phase 1 from 0 to 2 wk and Phase 2 from 2 to 5 wk. The diets were corn-soybean meal-based with either sugar beet pulp (SBP) or soybean hulls (SBH) as a fiber source and either soybean oil (SBO) or choice white grease (CWG) as a lipid source in a 2 × 2 factorial arrangement. The BW and feed intake were determined by phase, whereas visceral organ weights, intestinal histology, and gut microbial composition were determined at the end of the trial. Dietary fiber solubility and lipid source did not interact (P > 0.05) on average daily feed intake and average daily gain across all phases. However, the gain to feed ratio (G:F) for CWG-containing diets was lower (P < 0.05) than that for SBO-containing diets for Phase 1. Also, G:F for SBP-containing diets was lower (P < 0.05) than that for SBH-containing diets for Phase 1 and for the entire study period. Pigs fed SBP-containing diets had greater (P < 0.05) stomach weight, and tended to have greater (P < 0.10) small and large intestine weights relative to BW than those fed SBH-containing diets. Duodenal villous height to crypt depth ratio for CWG-based diets tended to be greater (P = 0.09) than that for SBO-based diets. Fiber solubility and lipid source interacted (P < 0.05) on relative abundance of Bacteroides in the colon such that the relative abundance of the Bacteroides for CWG was greater (P < 0.05) than that for the SBO in SBP-based diet, but not in SBH-based diet. Relative abundance of Butyricicoccus in the colon for SBH-based diet was greater (P < 0.05) than that for SBP-based diet. In conclusion, inclusion of SBH instead of SBP in corn-soybean meal-based diets for weaned pigs can result in increased feed efficiency and relative abundance of Butyricicoccus in the colon, which is associated with improved gut health. Also, inclusion of SBO instead of CWG in the diets for weaned pigs can result in improved feed efficiency during Phase 1 feeding; however, the pigs may recover from the low feed efficiency induced by dietary inclusion of CWG instead of SBO after Phase 1 feeding.