title: Mobilisation of blubber fatty acids of northern elephant seal pups (Mirounga angustirostris) during the post-weaning fast.
abstract: Northern elephant seal pups were longitudinally sampled at Año Nuevo State Reserve during the post-weaning fast, in order to evaluate the changes of fatty acid (FA) profiles in serum as well as in the inner and outer layers of blubber. The major FAs of inner and outer blubber layers were broadly similar to those found in NES maternal milk previously measured, suggesting a direct deposit of dietary FAs in the blubber during the suckling period. The outer blubber layer contained more medium-chain monounsaturated FAs that contribute in keeping the fluidity of this tissue at cold temperatures. It was compensated by higher proportions of saturated FAs in the inner blubber layer. The FA signature of inner blubber, the layer that is mainly mobilised during energy deprivation, slightly differed from the signature of serum. There were greater proportions of medium-chain saturated FAs and ω-6 polyunsaturated FAs, and lower proportions of long-chain saturated FAs, medium-chain monounsaturated FAs and long-chain monounsaturated FAs in serum as compared to inner blubber. We also demonstrated that lipophilicity is the main factor governing the mobilisation of FAs from blubber. The least lipophilic FAs were preferentially hydrolysed from blubber, leading to an enrichment of the more lipophilic FAs in this tissue with the progression of the fast. The expression levels of HSL and ATGL, which are two enzymes involved in the lipolytic process, remained stable during the post-weaning fast. This suggests that the pups have developed the enzymatic mechanisms for an efficient lipolysis as soon as the first week of fast.
authors.affiliation: Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Louis
authors.affiliation: Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Laurent
authors.initials: L
authors.lastname: Perdaens
authors.affiliation: Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Suciu
authors.affiliation: Bakersfield College, 1801 Panorama Dr, Bakersfield, CA 93305, USA; Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928, USA.
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Tavoni
authors.affiliation: Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928, USA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Crocker
authors.affiliation: Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium. Electronic address: cathy.debier@uclouvain.be.
authors.forename: Cathy
authors.initials: C
authors.lastname: Debier
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001835:Body Weight; D005215:Fasting / Q000502:physiology; D005227:Fatty Acids / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D005786:Gene Expression Regulation; D006868:Hydrolysis; D008049:Lipase / Q000235:genetics; D046048:Seals, Earless / Q000502:physiology; D002787:Sterol Esterase / Q000235:genetics; D014886:Weaning
chemical_list: D005227:Fatty Acids; D002787:Sterol Esterase; D008049:Lipase
keywords: Blubber; Fast; Fatty acids; Mobilisation; Northern elephant seal; Serum