Peripartal feeding strategy with different n-6: n-3 ratios in sows: effects on sows' performance, inflammatory and periparturient metabolic parameters.

The present study aimed to investigate the effects of two lactation sow feeds, differing in n-6:n-3 ratio, given to sows before parturition on body condition and feed intake, periparturient metabolism (leptin, insulin, triiodothyronine (T3) and thyroxine (T4)), inflammatory parameters (TNFalpha, IL-6, serum amyloid A (SAA)) and on piglet performance (birth weight, survivability). The feed contained either a low (supplemented with fish oil; f groups) or high (supplemented with sunflower-seed oil; s groups) n-6:n-3 ratio and was administered from 8 d (f8, s8) or 3 d (f3, s3) before parturition until weaning. The level of inclusion of the oil sources was 2 %. Seventy-two sows were randomly allocated 8 d before expected farrowing into four groups: f3, f8, s3, s8. Type of feed had a significant influence on the sows' feed intake during the first 2 d of lactation (s < f), leptin on days 4, 3 and 2 before parturition (f < s), insulin on day 1 after parturition (f < s), T4 on the day before parturition (s < f) and rectal temperature on the day after parturition (f < s). Onset of administration of the feed (3 v. 8 d) had significant effects on leptin on day 2 before parturition (8 < 3), insulin on day 4 before parturition (3 < 8), T3 on day 4 before parturition and on the day after parturition (3 < 8), SAA on day 3 after parturition (8 < 3) and piglet weight during the first days postpartum (3 < 8). In conclusion, under the present conditions, a lactation feed low in n-6:n-3 ratio administered from 8 d before farrowing ensures improved feed intake during the first days postpartum and was associated with a better metabolic change and inflammatory profile in sows in the periparturient period.