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.

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.

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) and d-xylose (linear, P=0·089), measured in serum 2 h post gavage with a solution containing 0·2 g/ml of d-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.