Can omega-3 fatty acids replace antibiotics in starter feeds?

Abstract Text: Omega-3 (n-3) fatty acids (FA) have anti-inflammatory properties, and are transferred to piglets via milk when fed to sows. This experiment was conducted to determine if improving piglet health prior to weaning, by supplementing the sows lactation diet with n-3 FA, would allow for removal of antibiotics (Ab) from nursery diets. Treatments, arranged as a 2 × 2 × 2 factorial, included the main effects of sow diet, weaning age, and nursery diet. Sows weaned at 26 ± 2 d (n = 52) or 19 ± 2 d (n = 51) were fed either a control diet or a diet with 3% flaxseed beginning one week pre-farrowing. At weaning, one half of each litter was fed a starter diet containing Ab (0.1% LS20), the other half the same diet without Ab (1181 piglets total). Litters were weaned into unwashed nurseries. All piglets exited the nursery at 54 ± 2 d of age. Performance and general health (measured by CBC and blood chemistry panels) were determined. There were no effects (P > 0.10) of sow diet (± n-3 FA) on sow lactation ADFI (6.75 ± 0.25 kg/d), live born piglets (14.72 ± 0.62), piglet ADG (0.25 ± 0.01 kg/d) or the number weaned per litter (11.46 ± 0.29). Sows fed the n-3 diet had greater total n-3 in their milk relative to control sows (2.61 vs. 1.55 ± 0.8%; P < 0.01). In the nursery, there was no impact of sow diet on ADG, ADFI or G:F of piglets regardless of weaning age (P > 0.10). Diet (sow or nursery) did not affect the final BW of piglets at nursery exit (19.45 ± 0.20 kg; P > 0.05); however, piglets weaned at 3 wks were 1.5 kg heavier than those weaned at 4 wks (20.20 vs. 18.69 ± 0.20 kg; P < 0.01). Regardless of treatment, piglets weaned at 3 wks had lower creatine kinase, aspartate aminotransferase and white blood cell counts (P< 0.05), indicating reduced muscle catabolism and immune responses. In this experiment, when piglets from a high health heard were raised in an unwashed nursery, neither n-3 FA during lactation, nor Ab in the nursery diets were beneficial, regardless of weaning age.

Keywords: omega-3 fatty acids, nursery, antibiotics