Effects of dietary n-6:n-3 fatty acid ratio on growth performance, plasma fatty acid profile, intestinal morphology, and immune function of pigs

• Published in: Livestock science 2020-08, Vol.238, p.104042, Article 104042
• Main Authors: Lu, N., Meyer, T.A., Bruckner, G., Monegue, H.J., Lindemann, M.D.
• Format: Article
• Language: English
• Subjects: average daily gain; cell-mediated immunity; corn oil; crossbreds; diet; duodenum; fatty acid composition; feed intake; growth performance; immune response; Immunity; inflammation; Intestinal morphology; jejunum; landraces; menhaden oil; n-6:n-3 fatty acids; omega-3 fatty acids; phosphates; phytohemagglutinin; Pigs; swine; villi
• ISSN: 1871-1413; 1878-0490
• DOI: 10.1016/j.livsci.2020.104042

•The increasing dietary n-6:n-3 fatty acid ratio altered plasma n-6 and n-3 fatty acid concentration as well as n-6:n-3 fatty acid ratio, and might influence the intestinal morphology during the nursery phase.•The increasing dietary n-6:n-3 fatty acid ratio did not generally affect growth performance or the skin inflammation response of pigs in the nursery and/or grower phases.•The extremely low dietary n-6:n-3 fatty acid ratios might have negative effects on the growth performance of pigs during the nursery phase. A total of 185 crossbred pigs (Yorkshire x Landrace; 20.7 ± 2.5 d of age and 6.7 ± 1.1 kg BW) from 3 weaning groups were used to evaluate dietary n-6:n-3 fatty acid (FA) ratios on nursery and growing pigs. Within each weaning group, pigs were blocked by BW and randomly assigned to 1 of 5 dietary treatments in a randomized complete block design with balanced sex and 4 or 5 pigs/pen within each block. The dietary treatments were: 1) low n-6:n-3 FA ratio (LO): 5.0% menhaden oil (MO) and 0.0% corn oil (CO); 2) low-medium n-6:n-3 FA ratio (LO-MED): 3.5% MO and 1.5% CO; 3) medium n-6:n-3 FA ratio (MED): 1.5% MO and 3.5% CO; 4) high-medium n-6:n-3 FA ratio (HI-MED): 0.2% MO and 4.8% CO; and 5) high n-6:n-3 FA ratio (HI): 0.0% MO and 5.0% CO. The diets were fed in 2 phases as d 0 to 28 (nursery phase) and d 29 to 70 (grower phase). In vivo cell-mediated immune response was assessed on d 14 and 28 for Group 1 and 2 by measuring the inflammatory response to an intradermal injection of 100 µL of phosphate buffered saline (PBS) or phytohemagglutinin (PHA, 0.5 mg/mL of PBS). One pig was euthanized from each pen in Group 1 and 2 at the end of the nursery and grower phase to assess intestinal morphology. During the nursery or grower phase, average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio were not affected by increasing dietary n-6:n-3 FA ratios (P > 0.16). However, pigs fed the LO diet had lower (P