Effects of rancidity and free fatty acids in choice white grease on growth performance and nutrient digestibility in weanling pigs1

Feeding thermally processed spray-dried egg whites, singly or in combination with 15-acetyldeoxynivalenol or peroxidized soybean oil on growth performance, digestibility, intestinal morphology, and oxidative status in nursery pigs

Two experiments (EXP) determined the susceptibility of spray-dried egg white (SDEW) to oxidation (heating at 100 °C for 72 h; thermally processed, TP) and whether feeding TP-SDEW, 15-acetyldeoxynivalenol (15-ADON), or peroxidized soybean oil (PSO), singularly or in combination, would affect pig performance, intestinal morphology, digestibility, and markers of oxidative stress in nursery pigs. In EXP 1, 32 pigs (7.14 kg body weight, BW) were placed individually into pens and fed diets containing either 12% SDEW, 6% TP-SDEW plus 6% SDEW, or 12% TP-SDEW. Performance was measured at the end of the 24-d feeding period with biological samples harvested following euthanasia. In EXP 2, 64 pigs (10.6 kg BW) were placed individually into pens and fed diets containing 7.5% soybean oil or PSO, 10% SDEW or TP-SDEW, and diets without or with 3 mg 15-ADON/kg diet in a 2 × 2 × 2 factorial arrangement. Performance was measured at the end of the 28-d feeding period with biological samples harvested following euthanasia. In EXP 1, dietary treatment did not affect pig performance, apparent ileal digestibility of amino acids (AAs), apparent total tract digestibility (ATTD) of gross energy (GE) or nitrogen (N), ileal crypt depth, or villi height:crypt depth ratio (P > 0.05). The effects of feeding TP-SDEW on protein damage in the plasma and liver (P < 0.05) were variable. In EXP 2, there were no three-way interactions and only one two-way interactions among dietary treatments on parameters evaluated. There was no effect of feeding TP-SDEW on ATTD of GE or N, intestinal morphology, or on oxidative markers in the plasma, liver, or ileum (P > 0.05). There was no effect of feeding diets containing added 15-ADON on ATTD of GE, ileal AA digestibility, intestinal morphology, oxidative markers in the plasma, liver, or ileum, or pig performance (P > 0.05). Feeding pigs diets containing PSO resulted in reduced ATTD of GE and N, plasma vitamin E concentration, and pig performance (P < 0.01) but did not affect intestinal morphology or oxidative markers in the liver or ileum (P > 0.05). In conclusion, it was difficult to induce protein oxidation in SDEW and when achieved there were limited effects on performance, digestibility, intestinal morphology, and oxidative status. Furthermore, singly adding 15-A-DON to a diet had no effect on the animal. At last, adding PSO reduces animal performance, but has limited effect on digestibility, intestinal morphology, and oxidative status in nursery pigs.

Invited review: strategic adoption of antibiotic-free pork production: the importance of a holistic approach

The discovery of the use of antibiotics to enhance growth in the 1950s proved to be one of the most dramatic and influential in the history of animal agriculture. Antibiotics have served animal agriculture, as well as human and animal medicine, well for more than seven decades, but emerging from this tremendous success has been the phenomenon of antimicrobial resistance. Consequently, human medicine and animal agriculture are being called upon, through legislation and/or marketplace demands, to reduce or eliminate antibiotics as growth promotants and even as therapeutics. As explained in this review, adoption of antibiotic-free (ABF) pork production would represent a sea change. By identifying key areas requiring attention, the clear message of this review is that success with ABF production, also referred to as "no antibiotics ever," demands a multifaceted and multidisciplinary approach. Too frequently, the topic has been approached in a piecemeal fashion by considering only one aspect of production, such as the use of certain feed additives or the adjustment in health management. Based on the literature and on practical experience, a more holistic approach is essential. It will require the modification of diet formulations to not only provide essential nutrients and energy, but to also maximize the effectiveness of normal immunological and physiological capabilities that support good health. It must also include the selection of effective non-antibiotic feed additives along with functional ingredients that have been shown to improve the utility and architecture of the gastrointestinal tract, to improve the microbiome, and to support the immune system. This holistic approach will require refining animal management strategies, including selection for more robust genetics, greater focus on care during the particularly sensitive perinatal and post-weaning periods, and practices that minimize social and environmental stressors. A clear strategy is needed to reduce pathogen load in the barn, such as greater emphasis on hygiene and biosecurity, adoption of a strategic vaccine program and the universal adoption of all-in-all-out housing. Of course, overall health management of the herd, as well as the details of animal flows, cannot be ignored. These management areas will support the basic biology of the pig in avoiding or, where necessary, overcoming pathogen challenges without the need for antibiotics, or at least with reduced usage.

Evidence-Based Challenges to the Continued Recommendation and Use of Peroxidatively-Susceptible Polyunsaturated Fatty Acid-Rich Culinary Oils for High-Temperature Frying Practises: Experimental Revelations Focused on Toxic Aldehydic Lipid Oxidation Products

In this manuscript, a series of research reports focused on dietary lipid oxidation products (LOPs), their toxicities and adverse health effects are critically reviewed in order to present a challenge to the mindset supporting, or strongly supporting, the notion that polyunsaturated fatty acid-laden frying oils are "safe" to use for high-temperature frying practises. The generation, physiological fates, and toxicities of less commonly known or documented LOPs, such as epoxy-fatty acids, are also considered. Primarily, an introduction to the sequential autocatalytic peroxidative degradation of unsaturated fatty acids (UFAs) occurring during frying episodes is described, as are the potential adverse health effects posed by the dietary consumption of aldehydic and other LOP toxins formed. In continuance, statistics on the dietary consumption of fried foods by humans are reviewed, with a special consideration of French fries. Subsequently, estimates of human dietary aldehyde intake are critically explored, which unfortunately are limited to acrolein and other lower homologues such as acetaldehyde and formaldehyde. However, a full update on estimates of quantities derived from fried food sources is provided here. Further items reviewed include the biochemical reactivities, metabolism and volatilities of aldehydic LOPs (the latter of which is of critical importance regarding the adverse health effects mediated by the inhalation of cooking/frying oil fumes); their toxicological actions, including sections focussed on governmental health authority tolerable daily intakes, delivery methods and routes employed for assessing such effects in animal model systems, along with problems encountered with the Cramer classification of such toxins. The mutagenicities, genotoxicities, and carcinogenic potential of aldehydes are then reviewed in some detail, and following this the physiological concentrations of aldehydes and their likely dietary sources are considered. Finally, conclusions from this study are drawn, with special reference to requirements for (1) the establishment of tolerable daily intake (TDI) values for a much wider range of aldehydic LOPs, and (2) the performance of future nutritional and epidemiological trials to explore associations between their dietary intake and the incidence and severity of non-communicable chronic diseases (NCDs).

Effects of Thermally Oxidized Vegetable Oil on Growth Performance and Carcass Characteristics, Gut Morphology, Nutrients Utilization, Serum Cholesterol and Meat Fatty Acid Profile in Broilers

The impacts of dietary levels of oxidized vegetable (sunflower) oil on growth performance, gut morphology, nutrients utilization, serum cholesterol and meat fatty acid profile were evaluated in Ross 308 straight-run (n = 192) day-old broilers. The broilers were arbitrarily distributed among four dietary treatments including; FVO: fresh vegetable oil (1 mEq kg−1), LOO: low oxidized (20 mEq kg−1), MOO: moderately oxidized (40 mEq kg−1), and HOO: highly oxidized vegetable oil (60 mEq kg−1) with 5% inclusion containing six replicates. Results revealed that the broilers consuming MOO and HOO based diets showed reduced (p = 0.05) feed intake, body weight gain and carcass weight accompanied by a poorer feed conversion ratio than those consuming FVO. Villus height, villus height to crypt depth ratio, ileal digestibility of crude protein (p = 0.041), crude fat (p = 0.032) and poly unsaturated fatty acids (p = 0.001) in thigh muscles were decreased, whereas crypt depth (p = 0.001), serum cholesterol levels (p = 0.023) and short chain fatty acids (p = 0.001) were increased (p < 0.001) by increasing dietary oxidation level. In conclusion, MOO and HOO exerted deleterious effects on growth, carcass weight, gut development and nutrients utilization. Low oxidized vegetable oil (20 mEq kg−1), however, with minimum negative effects can be used as a cost effective energy source in poultry diets.

Crude and acid oils from olive pomace as alternative fat sources in growing-finishing pigs

The inclusion of crude and acid oils from olive pomace can lead to more unsaturated meat products and, especially in the case of olive pomace acid oil, achieve a more economically and environmentally sustainable swine production. The objective of this trial was to study the effect of dietary supplementation with crude and acid oils from olive pomace, which are rich in monounsaturated fatty acids (FAs) and have differing free FA content, on growth performance, digestibility, carcass parameters and FA profile of Longissimus muscle (LM) and backfat in growing-finishing pigs compared to the conventional crude palm oil. A total of 224 male and female pigs [(Landrace × Large White) × Duroc] were randomly distributed into 48 pens according to initial BW (58.7 ± 9.71 kg, mean ± SD) and sex. Four experimental treatments were randomly assigned (n = 12 pens/treatment; 4-5 pigs/pen) for the growing (0-42 days) and finishing (40-62 days) phases. Treatments consisted of a basal diet supplemented with 5% (as-fed basis) palm oil (PO), olive pomace oil (O), olive pomace acid oil (OA) or a mixture (M) of PO and OA at 50/50. No differences were found in the growth performance results between PO, O or M, but animals fed OA showed a lower gain to feed ratio than M (P = 0.008). No differences were found in apparent ileal digestibility among treatments, however, animals fed O and OA showed the highest values of total FA apparent total tract digestibility, while those fed PO had the lowest values, and M had intermediate values (P < 0.001). No differences were observed in carcass composition among treatments. In relation to backfat and the LM FA profile, O and OA treatments led to a higher unsaturated FA to saturated FA ratio and a lower content in saturated FA than PO. Moreover, O showed a higher intramuscular fat (IMF) content in LM than PO (P = 0.037). It is concluded that olive pomace oil is an interesting alternative fat source that can be included at 5% in growing-finishing pig diets, leading to meat products with more IMF, rich in monounsaturated FA, reaching high FA digestibility values and good pig performance parameters. Alternatively, olive pomace acid oil blended with conventional palm oil did not negatively impact fat utilisation nor performance. Including these fat by-products reduced feeding costs and led to a more efficient and environmentally sustainable production.

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.

Maternal Exposure to Oxidized Soybean Oil Impairs Placental Development by Modulating Nutrient Transporters in a Rat Model

INTRODUCTION

As an exogenous food contaminant, dietary oxidized lipid impairs growth and development, and triggers chronic diseases in humans or animals. This study explores the effects of soybean oil with different oxidative degree on the placental injury of gestational rats.

METHODS AND RESULTS

Thirty-two female adult rats are randomly assigned to four groups. The control group is fed the purified diet with fresh soybean oil (FSO), and the treatment groups are fed purified diets with lipid content replaced by oxidized soybean oil (OSO) at 200, 400, and 800 mEqO2 kg-1 from conception until delivery. On day 20 of gestation, OSO decreased placental and embryonic weights as the oxidative degree increased linearly and quadratically. The expression of Bax showed a linear increase, and Bcl-2 decreased as the oxidative degree increased. The expression of Fosl1 and Esx1 is linearly and quadratically decreased in OSO-treated groups than FSO group. OSO decreased the level of IL-10 but increased expression of IL-1β in placenta and plasma. OSO remarkably upregulates levels of Fatp1 and Glut1 and decreases expression of Snat2 and Glut3.

CONCLUSION

OSO aggravates placental injury by modulating nutrient transporters and apoptosis-related genes, impedes placental growth and development, and ultimately leads to the decrease of fetal weight.

Feeding oxidized chicken byproduct meal impacts digestibility more than performance and oxidative status in nursery pigs

Rendered products from the meat industry provide quality proteins in diets for companion animals. These proteins are exposed to extreme temperatures during processing leading to the potential for decreased diet digestibility and subsequent growth performance. While this would impact production efficiency in livestock species, oxidized ingredients in companion animal diets may impact health and longevity. The objective of this study was to determine the extent to which a feedstuff containing oxidized protein and lipid affect diet digestibility, growth performance, and oxidative stress in nursery pigs. A total of 56 male pigs (21 d of age, initial body weight 5.51 ± 0.65 kg) were randomly assigned to one of the four dietary treatments in a 2 × 2 factorial arrangement with two levels of heat and two levels of antioxidant (AOX). Diets were fed for 35 d and growth performance was measured, while total tract digestibility and nitrogen (N) balance was determined during the trial on day 18–20. Blood plasma was collected on day 34 and jejunum, colon, and liver tissues were collected on day 35 to analyze for markers of oxidative stress. Average daily feed intake (ADFI) was reduced in pigs fed diets without AOXs (P = 0.02). Additionally, pigs consuming diets containing heated chicken byproduct (CBP) meal had decreased gain:feed (GF; P = 0.02). There was an interaction between heat and AOX (P = 0.02) where heating CBP reduced N digestibility in the presence of an AOX but did not have an impact when AOX was not present. The removal of AOX resulted in reduced GE digestibility (P < 0.01). Dry matter (P < 0.01), ash (P < 0.01), and protein (P < 0.01) digestibility were reduced (P < 0.01) as a result of heating. Furthermore, heating (P =0.01) as well as absence of AOX (P =0.01) resulted in reduced digestible energy. No difference was detected in N retention suggesting that oxidation reduces digestibility but has no impact on N utilization. This is supported by the fact that systemic oxidative stress was not consistently affected by heating or AOX inclusion. These results suggest that feeding pigs CBP containing oxidized proteins and lipids did not induce oxidative stress. However, feeding young pigs CBP containing oxidized proteins and lipids did result in reduced energy and nutrient digestibility as well as negatively affected feed efficiency. Because CBP is commonly used in companion animal diets, it is reasonable to revisit their impacts on those species.

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

Three experiments were conducted to evaluate oil source and peroxidation status (experiment 1) or peroxidized soybean oil (SO; experiments 2 and 3) on growth performance, oxidative stress, and digestibility of dietary ether extract (EE). In experiment 1, palm oil (PO), poultry fat (PF), canola oil (CO), and SO were evaluated, while in experiments 2 and 3, only SO was evaluated. Lipids were either an unheated control (CNT) or thermally processed at 90 °C for 72 hr, being added at 10%, 7.5%, or 3% of the diet in experiments 1, 2, and 3, respectively. In experiment 1, 288 pigs (body weight, BW, 6.1 kg) were fed 1 of 8 factorially arranged treatments with the first factor being lipid source (PO, PF, CO, and SO) and the second factor being peroxidation status (CNT or peroxidized). In experiment 2, 216 pigs (BW 5.8 kg) were fed 1 of 6 treatments consisting of 100%, 90%, 80%, 60%, 20%, and 0% CNT SO blended with 0%, 10%, 20%, 40%, 80%, and 100% peroxidized SO, respectively. In experiment 3, 72 pigs (BW 5.8 kg) were fed either CNT or peroxidized SO. Pigs were fed 21 d with feces collected on day 12 or 14 and pigs bled on day 12 blood collection. In experiment 1, an interaction between oil source and peroxidation status was observed for averaged daily gain (ADG) and average daily feed intake (ADFI; P = 0.10) which was due to no impact of feeding pigs peroxidized PO, PF, or SO on ADG or ADFI compared with feeding pigs CNT PO, PF, or SO, respectively; while pigs fed peroxidized CO resulted in reduced ADG and ADFI compared with pigs fed CNT CO. There was no interaction between oil source and peroxidation status, and no lipid source effect on gain to feed ratio (GF; P ≥ 0.84), but pigs fed the peroxidized lipids had a lower GF compared with pigs fed the CNT lipids (P = 0.09). In experiment 2, feeding pigs diets containing increasing levels of peroxidized SO resulted in reduced ADG (quadratic, P = 0.03), ADFI (linear, P = 0.01), and GF (quadratic, P = 0.01). In experiment 3, feeding peroxidized SO at 3% of the diet reduced ADG (P = 0.11) and ADFI (P = 0.13), with no observed change in GF (P = 0.62). Differences in plasma protein carbonyls, glutathione peroxidase, and vitamin E due to feeding peroxidized lipids were inconsistent across the 3 experiments. Digestibility of dietary EE was reduced in pigs fed peroxidized PO or SO (P = 0.01, experiment 1) and peroxidized SO in experiments 2 and 3 (P ≤ 0.02). In conclusion, the peroxidation status of dietary lipids consistently affects growth performance and EE digestibility but has a variable effect on measures of oxidative stress.

Effects of Commercial Antioxidants in Feed on Growth Performance and Oxidative Stress Status of Weaned Piglets

This work aimed to evaluate the effect of adding two different commercial antioxidants (AOX) products to pre-starter and starter diets using low vitamin E (Vit E as DL-α-tocopheryl acetate) levels on the growth performance and oxidative stress of piglets for the first six weeks post-weaning (PW). They were sorted by initial body weight (BW: 6.175 ± 0.931 kg) and randomly allotted to four dietary treatments (with six replicates per treatment): a positive control (PC) and a negative control (NC) diet, with normal and low dose of vitamin E (80 and 15 mg kg^-1, respectively), both without AOX; the other two experimental diets with a low dose of vitamin E (LVE) plus LOXIDAN VD100 (LVE + AOX1) or LOXIDAN E Ros (LVE + AOX2). Growth data were recorded, and blood samples were taken, at the beginning (day 0) and at the end of each feeding period: pre-starter and starter (at days 14 and 42, respectively). No differences among dietary treatments were found with respect to growth performance in the pre-starter period (p ≥ 0.05). However, at the end of the starter period, a lower BW was found in piglets fed the NC diet compared to the other dietary treatments. Differences in daily gain and feed conversion ratio were also found either for the starter period or when the whole period was considered (p < 0.05), whereby piglets fed PC or LVE diets supplemented with AOX showed better growth performance compared to piglets fed the NC diet. Regarding Vit E (α-tocopherol) serum levels, there were no differences among treatments at day 0; but the serum values of this vitamin decreased in LVE diets at 14 and 42 days, but not in the PC. On day 42, the highest levels of α-tocopherol in liver were also found in piglets fed PC (p < 0.05). Nevertheless, in general, from a metabolic point of view and after checking the serum biochemical profile of piglets, there were no differences in other oxidative stress markers (p ≥ 0.05). The results showed that the AOX products used were able to compensate for the lower Vit E supply with respect to growth performance in the starter phase. The use of AOXs or usual levels of Vit E in feed constitutes a key factor in achieving optimal growth performance of piglets in the PW period.

Composition and Nutritional Value of Acid Oils and Fatty Acid Distillates Used in Animal Feeding

Acid oils (AO) and fatty acid distillates (FAD) are oil refining by-products rich in free fatty acids. The objective of this study is their characterization and the identification of their sources of variability so that they can be standardized to improve their use as feed ingredients. Samples (n=92) were collected from the Spanish market and the MIU value (sum of moisture, insoluble impurities, and unsaponifiable matter), lipid classes, fatty acid composition, and tocol content were analyzed. Their composition was highly variable even between batches from the same producer. As FAD originated from a distillation step, they showed higher free fatty acid amounts (82.5 vs 57.0 g/100 g, median values), whereas AO maintained higher proportions of moisture, polymers, tri-, di-, and monoacylglycerols. Overall, the MIU value was higher in AO (2.60-18.50 g/100 g in AO vs 0.63-10.44 g/100 g in FAD), with most of the contents of insoluble impurities being higher than those in the guidelines. Tocol and fatty acid composition were influenced by the crude oil's botanical origin. The calculated dietary energy values were, in general, higher for AO and decreased when a MIU correction factor was applied. The analytical control and standardization of these by-products is of the outmost importance to revalorize them as feed ingredients.

Impact of storage conditions on protein oxidation of rendered by-product meals

Rendered products used in animal feed and pet food undergo extreme temperatures during manufacturing and may be stored up to 2 yr. No information is available on protein oxidation in these products. The objective of this study was to determine the extent to which typical antioxidant inclusion at different storage conditions may limit protein oxidation in typical rendered protein meals. Two experiments were conducted on 14 rendered products stored at either 45 °C for 7 or 14 d, or at 20 °C for 3 or 6 mo to determine the extent to which time, temperature, and antioxidants affect protein oxidation. Results from this study show that fish meal and chicken blood meal are susceptible to protein oxidation during storage at 45 °C (P = 0.05; 0.03) as well as during storage at 20 °C (P = 0.01; 0.04). Natural antioxidants were effective at limiting carbonyl formation in fish meal during short-term storage at 45 °C, whereas ethoxyquin was effective at limiting the extent of protein oxidation in fish meal stored long term at 20 °C.

Impact of dietary oxidized protein on oxidative status and performance in growing pigs

Rendered products from the meat industry can provide economical quality sources of proteins to the animal and feed industry. Similar to lipids, rendered proteins are susceptible to oxidation, yet the stability of these proteins is unclear. In addition, interest in understanding how oxidative stress can impact efficiency in production animals is increasing. Recent studies show that consumption of oxidized lipids can lead to a change in the oxidative status of the animal as well as decreases in production efficiency. To date, little is known about how consumption of oxidized proteins impacts oxidative status and growth performance. The objectives of this study were to determine if feeding diets high in oxidized protein to growing pigs would: 1) impact growth performance and 2) induce oxidative stress. Thirty pigs (42 d old; initial body weight [BW] 12.49 ± 1.45 kg) were randomly assigned to one of three dietary treatments with increasing levels of oxidized protein. Spray-dried bovine plasma was used as the protein source and was either unheated upon arrival, heated at 45 °C for 4 d, or heated at 100 °C for 3 d. Diets were fed for 19 d and growth performance was measured. Blood plasma (days 0 and 18), jejunum, colon, and liver tissues (day 19) were collected to analyze for markers of oxidative stress (e.g., protein oxidation, lipid oxidation, DNA damage, and glutathione peroxidase activity). Average daily gain (ADG;P < 0.01) and average daily feed intake (ADFI;P < 0.01) had a positive linear relationship to increased protein oxidation, but there was no effect on gain to feed ratio. Furthermore, protein (P = 0.03) and fat (P < 0.01) digestibility were reduced with increased protein oxidation in the diet. Crypt depth showed a positive linear relationship with dietary protein oxidation levels (P = 0.02). A trend was observed in liver samples where pigs fed the plasma heated to 45 °C had increased lipid oxidation compared with pigs fed the plasma either unheated or heated to 100 °C (P = 0.09). DNA damage in the jejunum tended to have a linear relationship with the dietary protein oxidation level (P = 0.07). Even though results suggest dietary oxidized protein did not induce oxidative stress during short-term feeding, differences in performance, gut morphology, and digestibility are likely a result of reduced protein availability.

Influence of feeding thermally peroxidized soybean oil on growth performance, digestibility, gut integrity, and oxidative stress in nursery pigs

The objectives of the current experiments were to evaluate the effect of feeding soybean oil (SO) with different levels of peroxidation on lipid, N, and GE digestibility, gut integrity, oxidative stress, and growth performance in nursery pigs. Treatments consisted diets containing 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each with an air infusion of 15 L/min, with postprocessing peroxide values of 7.6, 11.5, 19.1, and 13.4 mEq/kg and p-anisidine values of 1.92, 6.29, 149, and 159, for the 22.5 °C, 45 °C, 90 °C and 180 °C processed SO, respectively. In experiment 1, 64 barrows (7.1 ± 0.9 kg initial BW) were randomly allotted into 2 rooms of 32 pens and individually fed their experimental diets for 21 d, with a fresh fecal sample collected on day 20 for determination of GE and lipid digestibility. In experiment 2, 56 barrows (BW 9.16 ± 1.56 kg) were placed into individual metabolism crates for assessment of GE, lipid, and N digestibility and N retention. Urinary lactulose to mannitol ratio was assessed to evaluate in vivo small intestinal integrity, and urine and plasma were collected to analyze for markers of oxidative stress. Pigs were subsequently euthanized to obtain liver weights and analyze the liver for markers of oxidative stress. In experiment 1, pigs fed the SO thermally processed at 90 °C had reduced ADG (P = 0.01) and ADFI (P = 0.04) compared to pigs fed the other SO treatment groups, with no differences noted among pigs fed the 22.5 °C, 45 °C, and 180 °C SO treatments. No effects of feeding thermally processing SO on dietary GE or lipid digestibility (P > 0.10) were noted in either experiment. In experiment 2, there was no dietary effect of feeding peroxidized SO on the DE:ME ratio, N digestibility, or N retained as a percent of N digested, on the urinary ratio of lactulose to mannitol, on serum, urinary, or liver thiobarbituric acid reactive substances, on plasma protein carbonyls, or on urinary or liver 8-OH-2dG (P > 0.10). In experiment 2, pigs fed the SO thermally processed at 90 °C had the greatest isoprostane concentrations in the serum (P ≤ 0.01) and urine (P ≤ 0.05) compared to pigs fed the unprocessed SO. These results indicate that the change in fatty acid composition and/or the presence of lipid peroxidation products in peroxidized SO may reduce ADG and ADFI in nursery pigs, but appears to have no impact on GE, lipid, or N digestibility, or gut permeability. These data suggest that the presence of lipid peroxidation products may affect certain markers of oxidative stress.

Changes in markers of lipid oxidation and thermal treatment in feed-grade fats and oils

BACKGROUND

Oxidized feed lipids have been shown to have detrimental effects on food animal growth and metabolism. The present study aimed to measure classes of lipid oxidation products (LOP) in feed-grade oils at temperatures representing production and storage conditions.

RESULTS

There were significant oil type × time interactions in the accumulation of primary and secondary LOP. At 22.5 °C, peroxide value (PV), a marker for the primary phase of lipid oxidation, increased most in fish oil (FO), followed by tallow (TL), soybean oil (SO), linseed oil (LO) and modified algae oil (MAO), whereas palm oil (PO) showed no appreciable increase in PV. Secondary LOP, such as p-anisidine value, hexanal, 2,4,-decadienal, polymerized triacylglycerols and total polar compounds, increased only in FO. At 45 °C, FO and SO produced both primary and secondary LOP, whereas MAO, PO and TL had slower rates of PV increase and no secondary LOP. At 90 °C and 180 °C, all oils except for FO accumulated both primary and secondary LOP.

CONCLUSIONS

Higher polyunsaturated fatty acid:saturated fatty acid oils and higher temperatures produced greater quantities of primary and secondary LOP. However, unrefined TL was more prone to oxidation at 22.5 °C than predicted, whereas LO was more stable than predicted, indicating that pro-oxidant and antioxidant compounds can markedly influence the rate of oxidation. Measuring both primary and secondary LOP will provide better information about the oxidative status of feed oils and provide better information about which classes of LOP are responsible for detrimental health effects in animals. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

Identification of C9-C11 unsaturated aldehydes as prediction markers of growth and feed intake for non-ruminant animals fed oxidized soybean oil

Background

The benefits of using the oxidized oils from rendering and recycling as an economic source of lipids and energy in animal feed always coexist with the concerns that diverse degradation products in these oxidized oils can negatively affect animal health and performance. Therefore, the quality markers that predict growth performance could be useful when feeding oxidized oils to non-ruminants. However, the correlations between growth performance and chemical profiles of oxidized oils have not been well examined. In this study, six thermally oxidized soybean oils (OSOs) with a wide range of quality measures were prepared under different processing temperatures and processing durations, including 45 °C-336 h; 67.5 °C-168 h; 90 °C-84 h; 135 °C-42 h; 180 °C-21 h; and 225 °C-10.5 h. Broilers and nursery pigs were randomly assigned to diets containing either unheated control soybean oil or one of six OSOs. Animal performance was determined by measuring body weight gain, feed intake, and gain to feed ratio. The chemical profiles of OSOs were first evaluated by common indicative tests, including peroxide value, thiobarbituric acid reactive substances, p-anisidine value, free fatty acids, oxidized fatty acids, unsaponifiable matter, insoluble impurities, and moisture, and then analyzed by the liquid chromatography-mass spectrometry-based chemometric analysis.

Results

Among common quality indicators, p-anisidine value (AnV), which reflects the level of carbonyl compounds, had the greatest inverse correlation with the growth performance of both broilers and pigs, followed by free fatty acids and oxidized fatty acids. Among the 17 aldehydes identified in OSOs, C9-C11 alkenals, especially 2-decenal and 2-undecenal, had stronger inverse correlations (r < − 0.8) with animal performance compared to C5-C8 saturated alkanals, suggesting that chain length and unsaturation level affect the toxicity of aldehydes.

Conclusions

As the major lipid oxidation products contributing to the AnV, individual C9-C11 unsaturated aldehydes in heavily-oxidized oils could function as effective prediction markers of growth and feed intake in feeding non-ruminants.

Growth performance, oxidative stress and immune status of newly weaned pigs fed peroxidized lipids with or without supplemental vitamin E or polyphenols

Background

This study evaluated the use of dietary vitamin E and polyphenols on growth, immune and oxidative status of weaned pigs fed peroxidized lipids. A total of 192 piglets (21 days of age and body weight of 6.62 ± 1.04 kg) were assigned within sex and weight blocks to a 2 × 3 factorial arrangement using 48 pens with 4 pigs per pen. Dietary treatments consisted of lipid peroxidation (6% edible soybean oil or 6% peroxidized soybean oil), and antioxidant supplementation (control diet containing 33 IU/kg DL-α-tocopheryl-acetate; control with 200 IU/kg additional dl-α-tocopheryl-acetate; or control with 400 mg/kg polyphenols). Pigs were fed in 2 phases for 14 and 21 days, respectively.

Results

Peroxidation of oil for 12 days at 80 °C with exposure to 50 L/min of air substantially increased peroxide values, anisidine value, hexanal, and 2,4-decadienal concentrations. Feeding peroxidized lipids decreased (P < 0.001) body weight (23.16 vs. 18.74 kg), daily gain (473 vs. 346 g/d), daily feed intake (658 vs. 535 g/d) and gain:feed ratio (719 vs. 647 g/kg). Lipid peroxidation decreased serum vitamin E (P < 0.001) and this decrease was larger on day 35 (1.82 vs. 0.81 mg/kg) than day 14 (1.95 vs. 1.38 mg/kg). Supplemental vitamin E, but not polyphenols, increased (P ≤ 0.002) serum vitamin E by 84% and 22% for control and peroxidized diets, respectively (interaction, P = 0.001). Serum malondialdehyde decreased (P < 0.001) with peroxidation on day 14, but not day 35 and protein carbonyl increased (P < 0.001) with peroxidation on day 35, but not day 14. Serum 8-hydroxydeoxyguanosine was not affected (P > 0.05). Total antioxidant capacity decreased with peroxidation (P < 0.001) and increased with vitamin E (P = 0.065) and polyphenols (P = 0.046) for the control oil diet only. Serum cytokine concentrations increased with feeding peroxidized lipids on day 35, but were not affected by antioxidant supplementation (P > 0.05).

Conclusion

Feeding peroxidized lipids negatively impacted growth performance and antioxidant capacity of nursery pigs. Supplementation of vitamin E and polyphenols improved total antioxidant capacity, especially in pigs fed control diets, but did not restore growth performance.

Dietary methylsulfonylmethane supplementation and oxidative stress in broiler chickens

Methylsulfonylmethane (MSM) is an organic, sulfur-containing compound widely used as a dietary supplement to improve joint health and treat arthritic pain. An experiment was conducted to study the effects of feeding 0.05% MSM to broilers exposed to diet-induced oxidative stress on tissue MSM distribution, growth performance, oxidative stress biomarkers, and immune responsivity. A total of 528 birds were allocated to 4 dietary treatments (fresh oil-no MSM, fresh oil-MSM, oxidized oil-no MSM, oxidized oil-MSM) as provided ad libitum to 11 replicate cages of 12 birds per treatment. Blood and tissue samples were collected to analyze MSM concentrations, and oxidative stress biomarkers including concentrations of thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), total glutathione, and glutathione peroxidase (GPx) and reductase (GR) activities. Additionally, blood samples collected at day 25 were used to quantify T-cell (TC) populations using flow cytometry. Overall, MSM was quantified in all tissues and plasma samples of MSM-treated groups at all time points. Oxidized oil reduced (P = 0.006) feed intake over the 21-d feeding period, but MSM did not affect growth equally across time points. No effects (P > 0.2) of MSM or oil type were observed on TC populations. In the presence of oxidized oil, MSM reduced (P = 0.013) plasma TBARS and increased (P = 0.02) liver GPx at day 21, and increased (P = 0.06) liver GR at day 7. Irrespective of dietary oil type, groups supplemented with MSM showed higher plasma TAC at day 7 (P = 0.023), liver GPx activity at day 21 (P = 0.003), and liver GR activity at day 7 (P = 0.004) compared with groups not receiving MSM. In conclusion, 0.05% dietary MSM supplementation partially protected birds from oxidative stress but did not affect immune cell profiles.

Effects of chlorogenic acid-enriched extract from Eucommia ulmoides Oliver leaf on growth performance and quality and oxidative status of meat in finishing pigs fed diets containing fresh or oxidized corn oil

To investigate the effects of chlorogenic acid-enriched extract (CGAE) from Eucommia ulmoides Oliver leaf on growth performance and quality and oxidative status of meat in pigs fed diets containing fresh or oxidized corn oil, a total of 180 barrows (initial body weight: 81.6 ± 2.08 kg) were randomly allocated into 6 diet treatments (5 replicate pens per treatment and 6 barrows per pen) in a 2 × 3 factorial design with corn oil (fresh or oxidized corn oil at 5% inclusion of diet) and CGAE (0, 500 or 1,000 mg/kg of diet containing fresh or oxidized corn oil) as main factors. The experiment lasted for 6 weeks. Dietary oxidized oil reduced average daily gain (ADG, p < .05) and average daily feed intake (ADFI, p < .01) of pigs and pH₂₄ (p < .05), total antioxidant capacity (T-AOC, p < .01), glutathione peroxidase (GPx, p < .05) and sarcoplasmic reticulum Ca²⁺ -ATPase (SERCA, p < .05) activities in meat and increased drip loss (p < .01), cooking loss (p < .05), malondialdehyde (p < .01) and carbonyl (p < .01) contents and mRNA expression of superoxide dismutase 1 (SOD1, p < .05) in meat. Dietary CGAE supplementation at 1,000 mg/kg increased (p < .05) ADG and ADFI of pigs and pH₂₄ , T-AOC, T-SOD, GPx and SERCA activities and mRNA expression of SOD1 in meat and reduced (p < .05) drip loss, cooking loss, carbonyl and malondialdehyde contents in meat. No interaction effects between oxidized corn oil and CGAE were found in pigs. Overall, dietary CGAE supplementation at 1,000 mg/kg improved growth performance and quality and oxidative status of meat in pigs subjected or not to oxidative stress induced by dietary oxidized oil.

Lipid peroxidation impairs growth and viability of nursery pigs reared under commercial conditions1

The objective of this study was to investigate the impact of lipid peroxidation in a dose-dependent manner on growth, health, and oxidative stress status of nursery pigs. A total of 2,200 weaned pigs (5.95 ± 0.20 kg BW) were housed in 100 pens (22 pigs per pen) in a randomized complete block design based on initial BW and sex. Pigs were randomly assigned within blocks to 5 dietary treatments, consisting of a corn-soybean meal-based diet supplemented with 5% of either control corn oil (iodine value = 118, FFA = 0.06%, anisidine value = 3, peroxide value = 3 mEq/kg oil) or peroxidized corn oil (iodine value = 120, FFA = 0.35%, anisidine value = 30, peroxide value = 163 mEq/kg oil). These 2 diets were blended to obtain 5 levels of peroxidation with final treatments designated as 0 (diet with 5% control oil), 25%, 50%, 75%, and 100% (diet with peroxidized corn oil) peroxidation. Diets were fed ad libitum for 43 d. Blood samples were collected on d 33 from 20 pigs per treatment to determine serum oxidative stress markers and vitamin E concentrations and again on d 43 (14 d after vaccination) to determine immune response to porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (Mhyo). Gain:feed ratio decreased linearly (P = 0.023) with increasing peroxidation, but pen ADG and ADFI were not affected. Number of pigs removed for medical treatment, total number medically treated, pigs culled for low end weight, and mortality increased, and full-value pigs linearly decreased (P < 0.04) with increasing peroxidation. Consequently, total pen gain (weight of viable pigs that remained in test pens at the end of the study minus weight of pigs placed) decreased linearly (P < 0.01) with increasing peroxidation. Antibody titers to Mhyo and PCV2 increased postvaccination (P < 0.001), but did not differ due to dietary treatment. Serum concentrations of malondialdehyde, 8-hydroxy-2'-deoxyguanosine, and protein carbonyl were not affected by peroxidation. Total antioxidant capacity and serum vitamin E concentrations decreased (P = 0.01) linearly with increasing peroxidation. Data show a dose-dependent negative impact of lipid peroxidation on pig productivity when determined under field population conditions, being primarily manifested by increased mortality, number of pigs medically treated, and number of culled pigs (≤13.6 kg BW). Results underscore the importance of proper assessment of lipid peroxidation as part of quality control to prevent oxidative stress and performance losses in weaned pigs.

Addition of tert-butylhydroquinone (TBHQ) to maize oil reduces lipid oxidation but does not prevent reductions in serum vitamin E in nursery pigs

Background

Maize oil is abundantly used in foods and feeds and is highly susceptible to oxidation. Consequently, commercially available antioxidants should be evaluated for effectiveness against lipid oxidation in swine diets. Our study was conducted to evaluate growth performance of nursery pigs fed oxidized maize oil and to determine effects of using antioxidants on oxidative status in a 2 × 2 factorial design. Two hundred eight weaned pigs were blocked by initial BW into 13 blocks, resulting in 4 pigs per pen and 13 pens per treatment. Dietary treatments included 6% unoxidized or oxidized maize oil, and 0 or 60 mg/kg of tert-butylhydroquinone (TBHQ), which was added after lipid oxidation. Data for growth performance were collected from 5 time periods of a two-phase feeding program (Phase 1 = d 0 to 12 and Phase 2 = d 13 to 34). Serum and liver samples were collected from one pig per pen, which had initial BW closest to average BW to determine oxidative status on d 34.

Results

Oxidized maize oil was heated for 12 h at 185 °C with 12 L/min of air, yielding a peroxide value (PV) of 5.98 mEq O₂/kg and TBARS of 0.11 mg MDA eq/g. Addition of TBHQ to diets containing oxidized maize oil decreased PV by 37% and increased the oil stability index by 69%. Final BW, ADG, ADFI, and G:F of pigs were not different among the four dietary treatments. However, pigs fed oxidized maize oil tended (P <  0.08) to increase hepatosomatic index by 5% compared with those fed unoxidized oil, and this was not affected by adding TBHQ. The serum vitamin E concentration of pigs fed oxidized maize oil was less (P < 0.03) than pigs fed unoxidized oil, but this reduction was not reversed by adding TBHQ. Finally, the serum and liver selenium concentration were not different among the treatments.

Conclusions

The addition of TBHQ did not affect growth performance and vitamin E status in pigs fed moderately oxidized maize oil, but TBHQ reduced lipid oxidation, enhanced the oil stability, and appeared to reduce oxidative stress.

Effects of thermally oxidized canola oil and tannic acid supplementation on nutrient digestibility and microbial metabolites in finishing pigs1

The present study investigated the effects of oxidized canola oil and tannic acid (TA) supplementation on nutrient digestibility and microbial metabolites in finishing pigs. Four experimental diets were formulated to include 5% of either fresh canola oil (0 mEq/kg of peroxide value) or oxidized canola oil (180 mEq/kg of peroxide value). An equal portion of each diet was supplemented with 0.1% TA. Eight pigs (initial body weight of 82.89 ± 2.26 kg) were surgically fitted with a T-cannula at the distal ileum. At the beginning of the experiments, all pigs were fed a nitrogen-free diet for 7 d. Then, they were assigned to 4 dietary treatments according to an incomplete replicated 4 × 3 Latin square design with 3 periods to give 6 replicates per treatment. Each experimental period lasted for 9 d, starting with a 5-d adaptation period followed by 2 consecutive 2-d periods for fecal (day 6 and day 7) and ileal digesta (day 8 and day 9) collection. The inclusion of oxidized oil reduced (P < 0.05) the standardized ileal digestibility (SID) of Pro and the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of NDF. Also, pigs fed the oxidized oil tended to have lower (P ≤ 0.10) lactate and ammonia-nitrogen concentrations in the ileum and lower (P ≤ 0.10) acetate and propionate concentrations in the feces than those fed the fresh oil. The supplementation of 0.1% TA reduced (P < 0.05) the AID of NDF and the ATTD of gross energy, crude protein, and NDF. Additionally, the TA-supplemented diet tended to have a lower (P ≤ 0.10) digestible energy content than the nonsupplemented diet. Pigs fed the TA-supplemented diet showed reduced (P < 0.05) AID and SID of His, Cys, and Pro compared with those fed the nonsupplemented diet. There were interactive effects (P < 0.05) of oxidized oil and TA supplementation on acetate, isovalerate, total short chain fatty acids, and pH level in the ileum. In conclusion, the results indicated that the effects of oxidized oil are greater on microbial activities rather than nutrient digestibility. Although negative effects of dietary TA supplementation were observed in relation to nutrient digestibility, TA supplementation was found to ameliorate these negative effects of oxidized oil on microbial metabolites. Therefore, further studies are required to investigate the interaction between dietary oxidized oil and TA in relation with the gut microbiota in pigs.

Impact of a dietary challenge with peroxidized oil on the glutathione redox status and integrity of the small intestine in weaned piglets

Glutathione (GSH) is considered to play an important role in maintaining the integrity of the small intestine. In piglets, altered mucosal GSH levels might therefore be involved in weaning-induced changes of the small intestinal morphology and barrier function. To test this hypothesis, we aimed to challenge the mucosal GSH redox status during the first 28 days after weaning, by feeding diets containing 5% fresh linseed oil (CON), or 2.5% (OF1) or 5% (OF2) peroxidized linseed oil (peroxide value 225 mEq O2/kg oil) and exploring the effects on gut integrity. Piglets were pair-fed and had a total daily feed allowance of 32 g/kg BW. A fourth treatment included animals that were fed the control diet ad libitum (ACON). Animals were sampled at days 5 and 28 post-weaning. The malondialdehyde (MDA) concentration and GSH redox status (GSH/GSSG Eh) were determined in blood, liver and small intestinal mucosa. Histomorphology of the duodenal and jejunal mucosa was determined, and Ussing chambers were used to assess fluorescein isothiocyanate dextran (FD4) and horseradish peroxidase (HRP) fluxes across the mucosa. Results show that peroxidized linseed oil imposed an oxidative challenge at day 28, but not at day 5 post-weaning. At day 28, increasing levels of dietary peroxides to pair-fed pigs linearly increased MDA levels in duodenal and jejunal mucosa. Moreover, FD4 fluxes were significantly increased in OF1 (+75%) and OF2 (+64%) in the duodenum, and HRP fluxes tended (P=0.099) to show similar differences, as compared to CON. This co-occurred with a significant 11 mV increase of the hepatic GSH/GSSG Eh, potentiated by a significantly increased GSH peroxidase activity for treatments OF1 (+47%) and OF2 (+63%) in liver as compared to CON. Furthermore; duodenal HRP flux significantly correlated with the hepatic glutathione disulphide (GSSG) level (r=0.650), as also observed in the jejunum for hepatic GSSG (r=0.627) and GSH/GSSG Eh (r=0.547). The jejunal permeability was not affected, but FD4 and HRP fluxes significantly correlated with the local GSH (r=0.619; r=0.733) and GSSG (r=0.635; r=0586) levels. Small intestinal histomorphology was not affected by dietary lipid peroxides, nor were there any correlations found with the GSH redox system. To conclude, under oxidative stress conditions, jejunal barrier function is related to the local and hepatic GSH redox system. It is suggested that the hepatic GSH system participates in the elimination of luminal peroxides, and thereby impacts on duodenal barrier function.

Estimated energy and nutrient composition of different sources of food waste and their potential for use in sustainable swine feeding programs

About 40% of the total food produced in the United States is wasted throughout the supply chain. The objective of this study was to determine the energy and nutrient content and variability of food waste sources generated at different stages within the food supply chain in the Minneapolis–St. Paul, MN, metropolitan area, and their potential for use in swine diets. A total of four waste sources were selected: supermarket (SM; retail to consumer), university residential dining hall (RH; consumer to postconsumer), a city waste transfer station (TS; postconsumer to municipal waste disposal), and household source-separated organic recycling program (SSO; postconsumer to municipal waste). Samples were collected (SM: n = 22; RH: n = 60; TS: n = 27; SSO: n =12) and analyzed for GE, proximate analyses, minerals, amino acids, and fatty acid concentrations along with lipid peroxidation indicators including peroxide value (PV) and thiobarbituric reactive substances (TBARS). Data were analyzed using a general linear model that included food waste source as the main factor, and least squared means with adjustment were used for multiple comparisons. Samples of SM food waste contained the greatest (P < 0.05) concentration of GE (5,909 kcal/kg) compared with RH, TS, and SSO sources. Calculated NE of SM (3,740 kcal/kg) was also the greatest compared with the three other food waste sources. Food waste from SM, RH, and SSO, but not TS, had greater (P < 0.05) calculated NE than published values for corn and soybean meal. Concentrations of Lys (1.82%), Met (0.53%), Thr (1.07%), and Trp (0.27) content were greater in SM than in RH, TS, and SSO, but these concentrations were less than published values for soybean meal. There were no differences (P > 0.05) in the phosphorus content of samples among food waste sources (0.30% to 0.64%). PV and TBARS were greatest (P < 0.05) in the SSO samples (PV = 82.4 meq/kg oil; TBARS = 2.44 mg malondialdehyde (MDA) eq/g oil) compared with the other three food waste sources. Although the concentrations of nutrients and calculated energy values of the food waste sources were moderately high compared with corn and soybean meal, their composition was more variable (i.e., greater SD of means). Food waste generated upstream (SM) in the food supply chain appears to have greater nutritional value than postconsumer food waste (RH, TS, and SSO), but all sources appear suitable for use in commercial swine diets provided that ME, NE, and nutrient digestibility values are well characterized.

Influence of feeding thermally peroxidized soybean oil to finishing pigs on carcass characteristics, loin quality, and shelf life of loin chops

The objective of this study was to evaluate the effect of feeding soybean oil (SO) with varying levels of peroxidation on carcass traits and shelf life of loins. Fifty-six barrows were randomly assigned to 1 of 4 diets containing 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each infused with air at a rate of 15 liter/min. Individually housed pigs were provided ad libitum access to feed for 81 d. At 82 d, pigs were slaughtered and hot carcass weight and liver weights were recorded. Carcass characteristics and fresh loin quality were evaluated 1 d postmortem. Loin chops from each carcass were overwrap-packaged and subjected to a 10-d simulated retail display. Daily measurements of L*, a*, b*, reflectance, and visual discoloration were conducted, evaluation of cooking loss and Warner-Bratzler shear force (WBSF) was conducted on chops stored 0, 5, and 10 d, and thiobarbituric acid reactive substances (TBARS) were evaluated on chops stored 0 and 10 d. Shelf life-related data were analyzed as a completely randomized design with repeated measures in time, with storage location (shelf) as a random effect. Carcasses of 90 °C pigs weighed 6.0, 8.6, and 6.9 kg less (P < 0.03) than 22.5 °C, 45 °C, and 180 °C carcasses, respectively. Livers of 90 °C and 180 °C pigs were 14.3% and 11.7%, respectively, heavier (P ≤ 0.02) than those from pigs fed 22.5 °C SO, with livers of 45 °C being intermediate. Livers of 90 °C pigs represented 0.12 percentage units less (P = 0.02) of ending live weight than livers of 180 °C pigs, and 180 °C livers were 0.12 percentage units less (P < 0.01) of ending live weight than those from pigs fed 22.5 °C SO, with 45 °C being intermediate. There was no difference (P ≥ 0.19) in back fat depth, loin muscle area, or estimated carcass lean percentage among SO treatments, nor was there an effect (P ≥ 0.13) of SO on any early post-mortem loin quality traits or loin composition. There was no effect (P > 0.14) of SO on cooking loss, WBSF, L*, a*, b*, hue angle, reflectance, discoloration, or TBARS; however, there was a tendency (P = 0.09) for chops of 45 °C pigs to have greater (P < 0.04) chroma than either 22.5 °C or 180 °C, with 90 °C being intermediate. Overall, feeding SO cooked at 90 °C for 72 h resulted in reduced carcass weight and dressing percentage; however, there was no evidence that feeding peroxidized SO was detrimental to shelf life of loin chops.

Influence of feeding thermally peroxidized soybean oil on growth performance, digestibility, and gut integrity in finishing pigs

Consumption of peroxidized lipids has been shown to reduce pig performance and energy and lipid digestibility. Objectives of the current study were to evaluate the effect of feeding soybean oil (SO) with different levels of peroxidation on growth performance, lipid, N, and GE digestibility, plasma Trp, and gut integrity in finishing pigs. Fifty-six barrows (46.7 ± 5.1 kg initial BW) were randomly assigned to one of four diets in each of two dietary phases, containing either 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each infused with of 15 L/min of air. Peroxide values were 2.0, 17.4, 123.6, and 19.4 mEq/kg; 2,4-decadienal values were 2.07, 1.90, 912.15, and 915.49 mg/kg; and 4-hydroxynonenal concentrations were 0.66, 1.49, 170.48, and 82.80 mg/kg, for the 22.5, 45, 90, and 180 °C processed SO, respectively. Pigs were individually housed and fed ad libitum for 81 d to measure growth performance, including a metabolism period to collect urine and feces for determination of GE, lipid, N digestibility, and N retention. Following the last day of fecal and urine collection when pigs were in the metabolism crates, lactulose and mannitol were fed and subsequently measured in the urine to evaluate gut permeability, while markers of oxidative stress were evaluated in plasma, urine, and liver. There were no differences observed in ADFI (P = 0.91), but average daily gain (ADG) and gain:feed G:F were decreased in pigs fed 90 °C SO diet (P ≤ 0.07) compared to pigs fed the other SO diets. Pigs fed the 90 and 180 °C SO had the lowest (P = 0.05) DE as a % of GE compared to pigs fed the 22.5 °C SO, with pigs fed the 45 °C SO being intermediate. Lipid digestibility was similarly affected (P = 0.01) as energy digestibility, but ME as a % of DE was not affected by dietary treatment (P = 0.16). There were no effects of lipid peroxidation on N digested, N retained, or the urinary lactulose:mannitol ratio (P ≥ 0.25). Pigs fed the SO processed at 90 and 180 °1C had lower concentrations (P < 0.01) of plasma Trp compared to pigs fed the 22.5 and 45 °C SO treatments. Pigs fed 90 °C SO had the greatest (P < 0.01) concentrations of F2-isoprostane in plasma and urine thiobarbituric acid reactive substances compared to the other SO treatments. These results indicate that the change in FA composition and/or the presence of lipid peroxidation products in peroxidized SO may reduce ADG, G:F, and digestibility of GE and ether extract, but has little impact on N digestibility and balance or on gut permeability.

Identification of activation of tryptophan-NAD+ pathway as a prominent metabolic response to thermally oxidized oil through metabolomics-guided biochemical analysis

Consumption of thermally oxidized oil is associated with metabolic disorders, but oxidized oil-elicited changes in the metabolome are not well defined. In this study, C57BL/6 mice were fed the diets containing either control soybean oil or heated soybean oil (HSO) for 4 weeks. HSO-responsive metabolic events were examined through untargeted metabolomics-guided biochemical analysis. HSO directly contributed to the presence of new HSO-derived metabolites in urine and the decrease of polyunsaturated fatty acid-containing phospholipids in serum and the liver. HSO disrupted redox balance by decreasing hepatic glutathione and ascorbic acid. HSO also activated peroxisome proliferator-activated receptors, leading to the decrease of serum triacylglycerols and the changes of cofactors and products in fatty acid oxidation pathways. Most importantly, multiple metabolic changes, including the decrease of tryptophan in serum; the increase of NAD⁺ in the liver; the increases of kynurenic acid, nicotinamide and nicotinamide N-oxide in urine; and the decreases of the metabolites from pyridine nucleotide degradation in the liver indicated that HSO activated tryptophan-NAD⁺ metabolic pathway, which was further confirmed by the upregulation of gene expression in this pathway. Because NAD⁺ and its metabolites are essential cofactors in many HSO-induced metabolic events, the activation of tryptophan-NAD⁺ pathway should be considered as a central metabolic response to the exposure of HSO.

Influence of feeding thermally peroxidized soybean oil on growth performance, digestibility, and gut integrity in growing pigs

Consumption of highly peroxidized oils has been shown to affect pig performance and oxidative status through the development of compounds which differ according to how oils are thermally processed. The objective of this study was to evaluate the effect of feeding varying degrees of peroxidized soybean oil (SO) on parameters of growth performance; lipid, N, and GE digestibility, gut integrity in growing pigs, and plasma Trp. Fifty-six barrows (25.3 ± 3.3 kg initial BW) were randomly assigned to one of four diets containing either 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each with an air infusion of 15 L/min. Peroxide values for the 22.5, 45, 90, and 180 °C processed SO were 2.0, 96, 145, and 4.0 mEq/kg, respectively; 2,4-decadienal values for 22.5, 45, 90, and 180 °C processed SO were 2.11,5.05, 547.62, and 323.57 mg/kg, respectively; and 4-hydroxynonenal concentrations of 0.05, 1.05, 39.46, and 25.71 mg/kg with increasing SO processing temperature. Pigs were individually housed and fed ad libitum for a 49 d period to determine the effects of SO peroxidation status on growth performance, including a metabolism period for assessing GE and N digestibility, and N retention. In vivo urinary lactulose to mannitol ratio was also assessed to evaluate potential changes in small intestinal integrity. Although there were no differences observed in ADFI (P = 0.19), ADG was decreased in pigs fed 90 °C SO diet (P = 0.01), while G:F was increased (P = 0.02) in pigs fed 45 °C SO diet compared to the other SO diets. Pigs fed the 90 °C processed SO had the lowest (P = 0.01) DE as a percentage of GE, whereas ME as a percentage of DE was lowest (P = 0.05) in pigs fed the 180 °C SO and 90 °C SO followed by 45 °C SO and fresh SO. Ether extract (EE) digestibility was lowest (P = 0.01) in pigs fed 90 °C SO followed by pigs fed 180 °C SO, 45 °C SO, and fresh SO. The percent of N retained was greatest (P = 0.01) in pigs fed fresh SO followed by pigs fed 45 °C SO, 180 °C SO, and 90 °C, respectively. There were no differences observed among SO treatments for urinary lactulose to mannitol ratio (P = 0.60). Pigs fed SO processed at 90 °C and 180 °C had lower concentrations (P < 0.01) of serum Trp compared to pigs fed the 22.5 °C and 45 °C SO treatments. The presence of lipid peroxidation products, namely several aldehydes, contained in the 90 °C SO diet reduced ADG, GE and EE digestibility, and N balance, but had no impact on gut permeability.

Effects of oil quality and antioxidant supplementation on sow performance, milk composition and oxidative status in serum and placenta

BACKGROUND

The aim of this study was to determine the effects of oil quality and antioxidant (AOX) supplementation on sow performance, milk composition and oxidative status.

METHODS

A total of 80 PIC (PIC breeding, 3 ~ 5 parities) sows with similar body condition were allocated to four groups (n = 20), receiving diets including fresh corn oil, oxidized corn oil, fresh corn oil plus AOX and oxidized corn oil plus AOX, respectively, from d 85 of gestation to d 21 of lactation. AOX was provided at 200 mg/kg diet and mixed with corn oil prior to dietary formulation.

RESULTS

The results showed that sows fed oxidized corn oil had significantly lower feed intake (P < 0.05) during lactation period. Feeding oxidized corn oil markedly decreased (P < 0.05) the contents of protein and fat in colostrums and milk, but the addition of AOX in oxidized corn oil prevented the decrease on protein content of colostrums. Moreover, sows fed oxidized corn oil had significantly lower serum activities of total SOD and Mn-SOD across lactation (P < 0.05). In contrast, addition of AOX to oxidized corn oil tended to inhibit the production of MDA (P = 0.08) in sows across lactation relative to fresh oil. Intriguingly, the placental oxidative status was affected by oil quality and AOX supplementation, as indicated by the markedly increased placental gene expression of GPX and SOD (P < 0.05) in sows fed oxidized corn oil but normalized by supplementation of AOX.

CONCLUSION

In conclusion, feeding oxidized corn oil did not markedly affect reproductive performance in addition to decreasing feed intake during lactation. Milk composition and systemic oxidative status were deteriorated in sows fed oxidized corn oil and partially improved by AOX supplementation. Moreover, placental antioxidant system of sows may have an adaptive response to oxidative stress, but normalized by AOX.

Effects of tallow, choice white grease, palm oil, corn oil, or soybean oil on apparent total tract digestibility of minerals in diets fed to growing pigs

An experiment was conducted to determine the effect of supplementing diets fed to growing pigs with fat sources differing in their composition of fatty acids on the apparent total tract digestibility (ATTD) of minerals. A diet based on corn, potato protein isolate, and 7% sucrose was formulated. Five additional diets that were similar to the previous diet with the exception that sucrose was replaced by 7% tallow, choice white grease, palm oil, corn oil, or soybean oil were also formulated. Diets were formulated to contain 0.70% Ca and 0.33% standardized total tract digestible P. Growing barrows ( = 60; 15.99 ± 1.48 kg initial BW) were allotted to a randomized complete block design with 2 blocks of 30 pigs, 6 dietary treatments, and 10 replicate pigs per treatment. Experimental diets were provided for 12 d with the initial 5 d being the adaptation period. Total feces were collected for a 5-d collection period using the marker-to-marker approach, and the ATTD of minerals, ether extract, and acid hydrolyzed ether extract was calculated for all diets. Digestibility of DM was greater ( < 0.05) in the diet containing soybean oil compared with the diet containing choice white grease or the basal diet, with all other diets being intermediate. The ATTD of Ca, S, and P was greater ( < 0.05) for pigs fed diets containing soybean oil, corn oil, palm oil, or tallow than for pigs fed the basal diet or the diet containing choice white grease. The ATTD of Mg, Zn, Mn, Na, and K were not different among dietary treatments. The ATTD of ether extract was greater ( < 0.05) in diets containing palm oil, corn oil, or soybean oil compared with the diet containing choice white grease, and the ATTD of acid hydrolyzed ether extract in the diet containing soybean oil was also greater ( < 0.05) than in the diet containing choice white grease. In conclusion, supplementation of a basal diet with tallow, palm oil, corn oil, or soybean oil may increase the ATTD of some macrominerals, but that appears not to be the case if choice white grease is used. There was no evidence of negative effects of the fat sources used in this experiment on the ATTD of any minerals.

Essential fatty acid supplementation during lactation is required to maximize the subsequent reproductive performance of the modern sow

This study was conducted to investigate the effects of supplemental essential fatty acids (EFA) on sow reproductive efficiency and to estimate the concentrations of EFA required by the lactating sow for maximum subsequent reproduction. Data were collected on 480 sows (PIC Camborough) balanced by parity, with 241 and 239 sows representing Parity 1, and 3-5 (P3+), respectively. Sows were assigned randomly, within parity, to a 3 × 3 factorial arrangement plus a control diet without added lipids. Factors included linoleic (2.1%, 2.7%, and 3.3%) and α-linolenic acid (0.15%, 0.30%, and 0.45%), obtained by adding 4% of different mixtures of canola, corn and flaxseed oils to diets. Diets were corn-soybean meal based with 12% wheat middlings. The benefits of supplemental EFA were more evident for the subsequent reproduction of mature P3+ sows. For these sows, supplemental α-linolenic acid improved the proportion of sows that farrowed relative to sows weaned (linear P=0.080; 82.8, 80.5, and 92.8% for sows fed 0.15%, 0.30%, and 0.45% α-linolenic acid, respectively). In addition, supplemental linoleic acid, fed to Parity 1 and P3+ sows, tended to increase subsequent litter size (linear P=0.074; 13.2, 13.8 and 14.0 total pigs born for 2.1%, 2.7% and 3.3% linoleic acid, respectively). These results demonstrate that a minimum dietary intake of both α-linolenic and linoleic acid is required for the modern lactating sow to achieve a maximum reproductive outcome through multiple mechanisms that include rapid return to estrus, increased maintenance of pregnancy and improved subsequent litter size.

Impact of synthetic antioxidants on lipid peroxidation of distiller's dried grains with solubles and distiller's corn oil stored under high temperature and humidity conditions

This experiment evaluated the effect of antioxidants, oil content in distiller's dried grains with solubles (DDGS), quality of distiller's corn oil, and storage time on lipid peroxidation. A source of low-oil DDGS (LO-DDGS; 5.0% ether extract [EE], as-fed basis), high-oil DDGS (HO-DDGS; 13.0% EE, as-fed basis), and 2 sources of distiller's corn oil (DCO; 1.20, 0.08, and 0.48% moisture, insoluble impurities, and unsaponifiables [MIU], respectively [DCO-1], and 1.20, 0.01, and 0.10% MIU, respectively [DCO-2]) were obtained. Each of the 4 ingredients was divided into 18 representative subsamples (approximately 908 g for DDGS or 2 kg of DCO). Six subsamples of each ingredient were mixed with either no supplemental antioxidants (CON), Rendox-CQ (REN; 1,000 mg/kg EE; Kemin, Industries, Des Moines, IA), or Santoquin-Q4T (SAN; 1,500 mg/kg EE; Novus International, St. Louis, MO). Each mixture ( = 72) was split into thirds, and 1 portion was immediately frozen at -20°C (d 0). Two portions were stored under hot (38.6 ± 0.1°C) and humid conditions (94.0 ± 0.3% relative humidity) for 14 or 28 d. The MIXED procedure of SAS was used to evaluate the effects of ingredient, antioxidant, storage time, and interactions, with d-0 values used as a covariate. From d 14 to 28, peroxide value (PV), -anisidine value (AnV), and thiobarbituric acid reactive substances (TBARS) of DCO and DDGS increased by 3- to 4-fold ( < 0.05). Over the entire storage period, PV of DCO-1 and HO-DDGS (12.3 ± 0.3 and 12.6 ± 0.3 mEq O/kg oil, respectively) exceeded ( < 0.05) that of DCO-2 and LO-DDGS (9.6 ± 0.3 and 9.3 ± 0.3 mEq O/kg oil, respectively). Adding REN or SAN ( < 0.05) reduced TBARS and AnV relative to CON (TBARS = 11.0 ± 0.2 mg malondialdehyde Eq/kg oil and AnV = 6.5 ± 0.2) over the entire period (mean of d 14 and 28), but TBARS and AnV did not differ ( > 0.05) between antioxidants (TBARS = 6.1 ± 0.2 and 5.9 ± 0.2 mg malondialdehyde Eq/kg oil, respectively, and AnV = 1.9 ± 0.2 and 1.8 ± 0.2 for REN and SAN, respectively). The PV on d 14 and 28 and overall was less ( < 0.05) when either antioxidant was added relative to CON (16.0 mEq O/kg) and was greater for ingredients treated with SAN ( < 0.05) compared with REN (8.8 ± 0.2 and 8.0 ± 0.2 mEq O/kg oil for SAN and REN, respectively). In summary, antioxidants reduced peroxidation of DDGS and DCO by approximately 50% during 28 d of storage at 38.6°C and 94.0% relative humidity, but neither antioxidant completely stabilized the ingredients.

Peroxidised dietary lipids impair intestinal function and morphology of the small intestine villi of nursery pigs in a dose-dependent manner

The objective of this study was to investigate the effect of increasing degrees of lipid peroxidation on structure and function of the small intestine of nursery pigs. A total of 216 pigs (mean body weight was 6·5 kg) were randomly allotted within weight blocks and sex and fed one of five experimental diets for 35 d (eleven pens per treatment with three to four pigs per pen). Treatments included a control diet without added lipid, and diets supplemented with 6 % soyabean oil that was exposed to heat (80°C) and constant oxygen flow (1 litre/min) for 0, 6, 9 and 12 d. Increasing lipid peroxidation linearly reduced feed intake (P<0·001) and weight gain (P=0·024). Apparent faecal digestibility of gross energy (P=0·001) and fat (P<0·001) decreased linearly as the degree of peroxidation increased. Absorption of mannitol (linear,P=0·097) andd-xylose (linear,P=0·089), measured in serum 2 h post gavage with a solution containing 0·2 g/ml ofd-xylose and 0·3 g/ml of mannitol, tended to decrease progressively as the peroxidation level increased. Increasing peroxidation also resulted in increased villi height (linear,P<0·001) and crypt depth (quadratic,P=0·005) in the jejunum. Increasing peroxidation increased malondialdehyde concentrations (quadratic,P=0·035) and reduced the total antioxidant capacity (linear,P=0·044) in the jejunal mucosa. In conclusion, lipid peroxidation progressively diminished animal performance and modified the function and morphology of the small intestine of nursery pigs. Detrimental effects were related with the disruption of redox environment of the intestinal mucosa.

Use of re-esterified palm oils, differing in their acylglycerol structure, in fattening pig diets

Re-esterified oils are new fat sources obtained from the chemical esterification of acid oils with glycerol (both economically interesting by-products from oil refining and biodiesel industries, respectively). The different fatty acid (FA) positional distribution and acylglycerol composition of re-esterified oils may enhance the apparent absorption of saturated fatty acids (SFA) and, therefore, their overall nutritive value, which might lead to an increased deposition of SFA. The aim of the present study was to investigate the potential use of re-esterified palm oils, in comparison with their corresponding acid and native oils in fattening pig diets, studying their effects on fatty acid apparent absorption, acylglycerol and free fatty acid (FFA) composition of feces, growth performance, carcass-fat depots and fatty acid composition of backfat. Seventy-two crossbred boars and gilts (average weight of 24.7 ± 2.55 kg) were blocked by initial BW (nine blocks of BW for each gender), housed in adjacent individual boxes, and fed one of the four dietary treatments, which were the result of a basal diet supplemented with 4% (as-fed basis) of native palm oil (PN), acid palm oil (PA), re-esterified palm oil low in mono- and diacylglycerols (PEL), or re-esterified palm oil high in mono- and diacylglycerols (PEH). Regarding results from the digestibility balance, PA and PN showed similar apparent absorption coefficients (P>0.05), despite the high, FFA content of the former. However, re-esterified palm oils (both PEL and PEH) showed a higher apparent absorption of total FA than did their corresponding native and acid oils (P0.05). We conclude that re-esterified oils are interesting fat sources to be considered in fattening pigs.

Characteristics of lipids and their feeding value in swine diets

In livestock diets, energy is one of the most expensive nutritional components of feed formulation. Because lipids are a concentrated energy source, inclusion of lipids are known to affect growth rate and feed efficiency, but are also known to affect diet palatability, feed dustiness, and pellet quality. In reviewing the literature, the majority of research studies conducted on the subject of lipids have focused mainly on the effects of feeding presumably high quality lipids on growth performance, digestion, and metabolism in young animals. There is, however, the wide array of composition and quality differences among lipid sources available to the animal industry making it essential to understand differences in lipid composition and quality factors affecting their digestion and metabolism more fully. In addition there is often confusion in lipid nomenclature, measuring lipid content and composition, and evaluating quality factors necessary to understand the true feeding value to animals. Lastly, advances in understanding lipid digestion, post-absorption metabolism, and physiological processes (e.g., cell division and differentiation, immune function and inflammation); and in metabolic oxidative stress in the animal and lipid peroxidation, necessitates a more compressive assessment of factors affecting the value of lipid supplementation to livestock diets. The following review provides insight into lipid classification, digestion and absorption, lipid peroxidation indices, lipid quality and nutritional value, and antioxidants in growing pigs.

Impact of dietary lipids on sow milk composition and balance of essential fatty acids during lactation in prolific sows

Two studies were designed to determine the effects of supplementing diets with lipid sources of EFA (linoleic and α-linolenic acid) on sow milk composition to estimate the balance of EFA for sows nursing large litters. In Exp. 1, 30 sows, equally balanced by parity (1 and 3 to 5) and nursing 12 pigs, were fed diets supplemented with 6% animal-vegetable blend (A-V), 6% choice white grease (CWG), or a control diet without added lipid. Diets were corn-soybean meal based with 8% corn distiller dried grains with solubles and 6% wheat middlings and contained 3.25 g standardized ileal digestible Lys/Mcal ME. Sows fed lipid-supplemented diets secreted greater amounts of fat (P = 0.082; 499 and 559 g/d for control and lipid-added diets, respectively) than sows fed the control diet. The balance of EFA was computed as apparent ileal digestible intake of EFA minus the outflow of EFA in milk. For sows fed the control diet, the amount of linoleic acid secreted in milk was greater than the amount consumed, throughout lactation. This resulted in a pronounced negative balance of linoleic acid (-22.4, -38.0, and -14.1 g/d for d 3, 10, and 17 of lactation, respectively). In Exp. 2, 50 sows, equally balanced by parity and nursing 12 pigs, were randomly assigned to a 2 × 2 factorial arrangement of diets plus a control diet without added lipids. Factors included linoleic acid (2.1% and 3.3%) and α-linolenic acid (0.15% and 0.45%). The different concentrations of EFA were obtained by adding 4% of different mixtures of canola, corn, and flaxseed oils to diets. The n-6 to n-3 fatty acid ratios in the diets ranged from 5 to 22. Increasing supplemental EFA increased (P < 0.001) milk concentrations of linoleic (16.7% and 20.8%, for 2.1% and 3.3% linoleic acid, respectively) and α-linolenic acid (P < 0.001; 1.1 and 1.9% for 0.15 and 0.45% α-linolenic acid, respectively). Increasing supplemental EFA increased the estimated balance of α-linolenic acid (P < 0.001; -0.2 and 5.3 g/d for 0.15% and 0.45% α-linolenic acid, respectively), but not linoleic acid (P = 0.14; -3.4 and 10.0 g/d for 2.1% and 3.3% linoleic acid, respectively). In conclusion, lipid supplementation to sow lactation diets improved milk fat secretion. The fatty acid composition of milk fat reflected the dietary supplementation of EFA. The net effect of supplemental EFA was to create a positive balance during lactation, which may prove to be beneficial for the development of nursing piglets and the subsequent reproduction of sows.

Use of re-esterified palm oils, differing in their acylglycerol structure, in weaning-piglet diets

Re-esterified oils are new fat sources obtained from chemical esterification of acid oils with glycerol (both economically interesting by-products from oil refining and biodiesel industries, respectively). The different fatty acid (FA) positional distribution and acylglycerol composition of re-esterified oils may enhance the apparent absorption of saturated fatty acids (SFA) and, thus, their overall nutritive value. The aim of the present study was to investigate the potential use of re-esterified palm oils, in comparison with their corresponding acid and native oils, and also with an unsaturated fat source in weaning-piglet diets. The parameters assessed were: FA apparent absorption, acylglycerol and free fatty acid (FFA) composition of feces, and growth performance. One-hundred and twenty weaning piglets (average weight of 8.50±1.778 kg) were blocked by initial BW (six blocks) and randomly assigned to five dietary treatments, resulting in four piglets per pen and six replicates per treatment. Dietary treatments were a basal diet supplemented with 10% (as-fed basis) of native soybean oil (SN), native palm oil (PN), acid palm oil (PA), re-esterified palm oil low in mono- (MAG) and diacylglycerols (DAG) (PEL), or re-esterified palm oil high in MAG and DAG (PEH). Results from the digestibility balance showed that SN reached the greatest total FA apparent absorption, and statistically different from PN, PA and PEL (P0.05), but PEH achieved the greatest total FA apparent absorption. Animals fed PEL, despite the fact that PEL oil contained more sn-2 SFA, did not show an improved absorption of SFA (P>0.05). Animals fed PA and PN showed similar apparent absorption coefficients (P>0.05), despite the high FFA content of PA oil. The acylglycerol and FFA composition of feces was mainly composed of FFA. There were no significant differences in growth performance (P>0.05). Results of the present study suggest that, despite the different acylglycerol structure of re-esterified oils, there were no significant differences in digestibility or performance with respect to their corresponding PN and PA oils in weaning-piglet diets.

Evaluating the quality of feed fats and oils and their effects on pig growth performance

Feed fats and oils provide significant amounts of energy to swine diets, but there is large variation in composition, quality, feeding value, and price among sources. Common measures of lipid quality include moisture, insolubles, and unsaponifiables (MIU), titer, and free fatty acid content, but provide limited information regarding their feeding value. Lipid peroxidation is an important quality factor related to animal growth performance and health, but maximum tolerable limits in various lipids have not been established. Several indicative assays can be used to detect the presence of various peroxidation compounds, but due to the complexity and numerous compounds produced and degraded during peroxidation process, no single method can adequately determine the extent of peroxidation. Until further information is available, using a combination of peroxide value, thiobarbituric acid reactive substances (TBARS), and anisidine value appear to provide a reasonable assessment of the extent of peroxidation in a lipid at a reasonable cost. However, fatty acid composition of the lipid being evaluated should be considered when selecting specific assays. Predictive tests can also be used to estimate the stability or susceptibility of lipids to peroxidation and include active oxygen method, oil stability index, and oxygen bomb method. A review of 16 published studies with pigs has shown an average decrease of 11.4% in growth rate, 8.8% feed intake fed isocaloric diets containing peroxidized lipids compared to diets containing unperoxidized lipids of the same source. Furthermore, serum vitamin E content was generally reduced and serum TBARS content was increased when peroxidized lipids were fed in these studies, suggesting that feeding peroxidized lipids negatively affects metabolic oxidative status of pigs. However, it is unclear if antioxidants are useful additions to lipids to maintain optimal nutritional value, or if their addition to swine diets is beneficial in overcoming a metabolic oxidative challenge.

Effect of feeding peroxidized dried distillers grains with solubles to sows and progeny on growth performance and metabolic oxidative status of nursery pigs

This experiment evaluated the effects of including peroxidized corn dried distillers grains with solubles (DDGS) in diets for sows and nursery pigs on growth performance, vitamin E (VE), and Se status, and the incidence of mulberry heart disease (MHD) of nursery pigs. Sows (n = 12) were fed corn-soybean meal diets (C-SBM) or C-SBM diets with DDGS (40% and 20% in gestation and lactation, respectively) for 3 parities. In the third parity, 108 weaned pigs (BW = 6.6 ± 0.36 kg) were blocked by BW within litter, assigned to pens (2 pigs/pen; 5 and 4 pens per litter for groups 1 and 2, respectively), and pens were assigned 1 of 3 nursery diets: 1) corn-soybean meal (CON), 2) 30% peroxidized DDGS (Ox-D), and 3) 30% Ox-D with 5 × NRC (1998) level of VE (Ox-D+5VE) for 7 wk, in a 2 × 3 factorial arrangement of sow and nursery diets (n = 9 pens/treatment). The peroxidized DDGS source in nursery diets contained concentrations of thiobarbituric acid reactive substances (TBARS) and peroxide values that were 25 and 27 times greater than a reference corn sample. Sow colostrum, milk, and serum, as well as pig serum and liver samples, were analyzed for α-tocopherol and Se concentrations. Pig serum was analyzed for glutathione peroxidase activity (GPx), TBARS, and sulfur-containing AA (SAA). Pig hearts were evaluated for gross and histopathological lesions indicative of MHD, but none were detected. Pigs from sows fed DDGS tended to have reduced (P = 0.07) VE in serum during lactation and reduced VE at weaning (P < 0.01; 5.6 vs. 6.7 ± 0.1 µg/mL) compared with pigs from sows fed C-SBM. Inclusion of DDGS in sow diets reduced the VE status of pigs during lactation, but not in the nursery when MHD can be a concern. Pigs fed Ox-D+5VE (P = 0.08) tended to have, and those fed Ox-D (P = 0.04) had greater ADFI than pigs fed CON, but ADG was not affected (P > 0.1) by nursery diet. Feeding Ox-D or Ox-D+5VE increased (P < 0.05) serum α-tocopherol compared with CON (2.5, 2.8, and 3.4 ± 0.09 µg/mL, respectively), but TBARS and GPx were not affected by nursery diet. Serum concentration of SAA was 40% to 50% greater (P < 0.01) for pigs fed Ox-D or Ox-D+5VE compared with those fed C-SBM, which was likely due to greater (P < 0.01) SAA intake for pigs fed Ox-D. The antioxidant properties of SAA may have spared VE and Se and masked any effect of Ox-D on metabolic oxidation status. Therefore, increasing the dietary VE concentration was unnecessary in nursery diets containing Ox-D.

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

The objective of the study was to determine the effects of a dietary antioxidant blend (ethoxyquin and propyl gallate) and vitamin E on growth performance, liver function, and oxidative status in pigs fed diets high in oxidants. Crossbred barrows (n=100, 10.91±0.65 kg BW, 36±2 d of age, Landrace×Duroc) were allotted to 5 treatments on the basis of BW (5 replicate pens per treatment, 4 pigs per pen). Treatments included 1) HO, high-oxidant diet containing 5% oxidized soybean oil and 10% PUFA source (providing 2.05% docosahexaenoic acid in 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. The trial lasted for 118 d; on d 83, the HO diet pigs were switched to the SC diet because the animals were displaying very poor health. Compared with SC pigs, HO pigs had decreased ADG (0.92 vs. 0.51 kg for d 26 to 55, 1.29 vs. 0.34 kg for d 56 to 82; P<0.05) and ADFI (1.84 vs. 0.96 kg for d 26 to 55, 3.41 vs. 1.14 kg for d 56 to 82; P<0.05). However, switching the HO pigs to the SC diet resulted in HO pigs having a greater ADG than VE-fed pigs from d 83 to 118 (0.90 vs. 0.60 kg; P<0.05). The antioxidant blend restored pig performance to a level similar that of pigs fed the SC diet (P>0.05) with greater G:F for the entire period (0.44 vs. 0.38; P<0.05). A greater liver to BW ratio was found in HO compared with other treatments on d 55 and in VE on d 118. Total bilirubin concentration in plasma of HO pigs on d 55 was greater than that in VE+AOX pigs (P<0.05), whereas on d 118, bilirubin concentration in VE was higher than those in VE+AOX and SC (P<0.05). A similar trend was observed in aspartate transaminase. Plasma concentrations of thiobarbituric acid reactive substances (TBARS) and carbonyl were elevated (P<0.05) in the HO pigs compared with the SC pigs on d 55 but not on d 118. Liver TBARS and carbonyl concentrations showed a similar trend, except that HO pigs had the greatest carbonyl concentration on d 118. Pigs fed AOX diets had plasma and liver TBARS and carbonyl concentrations similar to those fed SC diets. In the oxidative stress model used in this study, dietary addition of antioxidant blend or antioxidant blend+vitaimin E was effective in improving growth, liver function, and plasma markers of oxidative stress, but VE alone was not.

Influence of thermally oxidized vegetable oils and animal fats on energy and nutrient digestibility in young pigs

A total of 108 barrows (6.67 ± 0.03 kg BW) were assigned to 12 dietary treatments in a 4 × 3 factorial design plus a corn-soybean meal control diet to evaluate the effect of lipid source and peroxidation level on DE, ME, and apparent total tract digestibility (ATTD) of DM, GE, ether extract (EE), N, and C in young pigs. Main effects were lipid source (corn oil [CN], canola oil [CA], poultry fat [PF], and tallow [TL]) and peroxidation level (original lipids [OL], slow oxidation [SO] of lipids heated for 72 h at 95°C, or rapid oxidation [RO] of lipids heated for 7 h at 185°C). Pigs were provided ad libitum access to diets for 28 d followed by an 8-d period of controlled feed intake equivalent to 4% BW daily. Diets were formulated based on the ME content of CA with the standardized ileal digestible Lys, Met, Thr, Trp, total Ca, and available P:ME balanced relative to NRC (1998) recommendations. Lipid peroxidation analysis indicated that compared with the OL, SO and RO had a markedly increased concentrations of lipid peroxidation products, and the increase of peroxidation products in CN and CA were greater than those in PF and TL. Addition of lipids to diets increased (P < 0.05) ATTD of EE and tended to improve (P = 0.06) ATTD of GE compared with pigs fed the control diet. Feeding CN or CA increased (P < 0.05) ATTD of DM, GE, EE, N, and C compared with feeding TL, while feeding PF improved (P < 0.05) ATTD of GE and EE and tended to increase (P = 0.06) ATTD of C compared with TL. Pigs fed CN had increased (P = 0.05) percentage N retention than pigs fed TL. No peroxidation level effect or interaction between lipid source and peroxidation level on DE and ME was observed. Lipid source tended (P = 0.08) to affect DE but not ME values of experimental lipids (P > 0.12). Digestible energy values for CA (8,846, 8,682, and 8,668 kcal/kg) and CN (8,867, 8,648, and 8,725 kcal/kg) were about 450 kcal/kg greater than that of TL (8,316, 8,168, and 8,296 kcal/kg), with PF being intermediate (8,519, 8,274, and 8,511 kcal/kg), for OL, SO, and RO lipids, respectively, respectively. In conclusion, lipid source affected ATTD of dietary DM, GE, EE, N, and C, and N retention and tended to influence the DE value of the lipid but did not significantly affect their ME value. Rapid and slow heating of lipids used in this study increased lipid peroxidation products but had no detectable effects on nutrient and energy digestibility as well as DE and ME values of the various lipids.

Methods to create thermally oxidized lipids and comparison of analytical procedures to characterize peroxidation

The objective of this experiment was to evaluate peroxidation in 4 lipids, each with 3 levels of peroxidation. Lipid sources were corn oil (CN), canola oil (CA), poultry fat, and tallow. Peroxidation levels were original lipids (OL), slow-oxidized lipids (SO), and rapid-oxidized lipids (RO). To produce peroxidized lipids, OL were either heated at 95°C for 72 h to produce SO or heated at 185°C for 7 h to produce RO. Five indicative measurements (peroxide value [PV], p-anisidine value [AnV], thiobarbituric acid reactive substances [TBARS] concentration, hexanal concentration, 4-hydroxynonenal [HNE] concentration, and 2,4-decadienal [DDE]) and 2 predictive tests (active oxygen method [AOM] stability and oxidative stability index [OSI]) were performed to quantify the level of oxidation of the subsequent 12 lipids with varying levels of peroxidation. Analysis showed that a high PV accurately indicated the high level of lipid peroxidation, but a moderate or low PV may be misleading due to the unstable characteristics of hydroperoxides as indicated by the unchanged PV of rapidly oxidized CN and CA compared to their original state (OL). However, additional tests, which measure secondary peroxidation products such as AnV, TBARS, hexanal, HNE, and DDE, may provide a better indication of lipid peroxidation than PV for lipids subjected to a high level of peroxidation. Similar to PV analysis, these tests may also not provide irrefutable information regarding the extent of peroxidation because of the volatile characteristics of secondary peroxidation products and the changing stage of lipid peroxidation. For the predictive tests, AOM accurately reflected the increased lipid peroxidation caused by SO and RO as indicated by the increased AOM value in CN and CA but not in poultry fat and tallow, which indicated a potential disadvantage of the AOM test. Oxidative stability index successfully showed the increased lipid peroxidation caused by SO and RO in all lipids, but it too may have disadvantages similar to AnV, TBARS, hexanal, DDE, and HNE because OSI directly depends on quantification of the volatile secondary peroxidation products. To accurately analyze the peroxidation damage in lipids, measurements should be determined at appropriate time intervals by more than 1 test and include different levels of peroxidation products simultaneously.