Dietary Fish Oil Inhibits Pro-Inflammatory and ER Stress Signalling Pathways in the Liver of Sows during Lactation.
Lactating sows have been shown to develop typical signs of an inflammatory condition in the liver during the transition from pregnancy to lactation. Hepatic inflammation is considered critical due to the induction of an acute phase response and the activation of stress signaling pathways like the endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR), both of which impair animal's health and performance. Whether ER stress-induced UPR is also activated in the liver of lactating sows and whether dietary fish oil as a source of anti-inflammatory effects n-3 PUFA is able to attenuate hepatic inflammation and ER stress-induced UPR in the liver of sows is currently unknown. Based on this, two experiments with lactating sows were performed. The first experiment revealed that ER stress-induced UPR occurs also in the liver of sows during lactation. This was evident from the up-regulation of a set of genes regulated by the UPR and numerically increased phosphorylation of the ER stress-transducer PERK and PERK-mediated phosphorylation of eIF2α and IκB. The second experiment showed that fish oil inhibits ER stress-induced UPR in the liver of lactating sows. This was demonstrated by decreased mRNA levels of a number of UPR-regulated genes and reduced phosphorylation of PERK and PERK-mediated phosphorylation of eIF2α and IκB in the liver of the fish oil group. The mRNA levels of various nuclear factor-κB-regulated genes encoding inflammatory mediators and acute phase proteins in the liver of lactating sows were also reduced in the fish oil group. In line with this, the plasma levels of acute phase proteins were reduced in the fish oil group, although differences to the control group were not significant. In conclusion, ER stress-induced UPR is present in the liver of lactating sows and fish oil is able to inhibit inflammatory signaling pathways and ER stress-induced UPR in the liver.
Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Denise K
DK
Gessner
Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Birthe
B
Gröne
Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Aline
A
Couturier
Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Susann
S
Rosenbaum
Department of Veterinary Clinical Sciences, Swine Diseases, Justus-Liebig-Universität Giessen, Frankfurter Strasse 112, 35392, Giessen, Germany.
Sonja
S
Hillen
Department of Veterinary Clinical Sciences, Swine Diseases, Justus-Liebig-Universität Giessen, Frankfurter Strasse 112, 35392, Giessen, Germany.
Sabrina
S
Becker
Institute for Animal Breeding and Genetics, Justus-Liebig-Universität Giessen, Ludwigstrasse 21b, 35390, Giessen, Germany.
Georg
G
Erhardt
Department of Veterinary Clinical Sciences, Swine Diseases, Justus-Liebig-Universität Giessen, Frankfurter Strasse 112, 35392, Giessen, Germany.
Gerald
G
Reiner
Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Robert
R
Ringseis
Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Klaus
K
Eder
D000818:Animals; D002097:C-Reactive Protein / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D005260:Female; D005395:Fish Oils / Q000378:metabolism* / Q000494:pharmacology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D020672:I-kappa B Proteins / Q000378:metabolism; D058847:Inflammasomes / Q000235:genetics / Q000378:metabolism; D007774:Lactation; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D013552:Swine; D056811:Unfolded Protein Response / Q000235:genetics; D019892:eIF-2 Kinase / Q000378:metabolism
D015852:Eukaryotic Initiation Factor-2; D005395:Fish Oils; D020672:I-kappa B Proteins; D058847:Inflammasomes; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; D012333:RNA, Messenger; D002097:C-Reactive Protein; D019892:eIF-2 Kinase