DOI: 10.5061/dryad.3r2280gsw
title: Data from: Biosynthesis of long-chain omega-3 fatty acids in a generalist seabird

description: Docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid (n3-LCPUFA),
 is integral to vertebrates’ brains. Mammals require continuous DHA
 replenishment to maintain cerebral function and structural integrity;
 evidence points towards birds having similar requirements. Vertebrates
 maintain their DHA levels by endogenously synthesizing DHA using
 alpha-linolenic acid (ALA; omega-3 precursor) or by consuming preformed
 DHA and other n3-LCPUFAs. Given n3-LCPUFAs’ abundance in marine organisms,
 marine predators are presumed incapable of biosynthesizing n3-LCPUFAs;
 this assumption remains seldom tested. Alarmingly, many marine predators,
 including generalist seabirds, now forage on anthropogenic resources
 deficient in n3-LCPUFAs. Whether they can offset such deficiency by
 bioconverting ALA into DHA remains unknown. Here, we tested whether
 ring-billed gulls (Larus delawarensis), a generalist seabird now thriving
 in cities, can biosynthesize n3-LCPUFAs, including DHA, from ALA. We
 brought into captivity 24 hatchlings from two breeding colonies, including
 12 from an urban colony and 12 from a natural colony. Nine hatchlings from
 each colony received an oral 13C-enriched ALA tracer to follow the
 potential bioconversion of ALA into n3-LCPUFAs, in addition to being fed
 490 μL of unlabelled ALA daily for three days. The control groups (N=3
 urban hatchlings and 3 natural hatchlings) received a caloric equivalent
 (free of omega-3s) in place of the ALA tracer and supplement. All chicks
 received a diet deficient in all omega-3s throughout the 72 hours of
 captivity. We analyzed their brains’ and livers’ fatty acid content and
 established their 13C signatures for each omega-3 using compound-specific
 isotope analysis. We found evidence of incomplete ALA bioconversion where,
 compared to controls, experimental chicks from both colonies accumulated
 more of all ALA derivates in their tissues except for DHA. We demonstrate
 for the first time that a seabird shows some omega-3 bioconversion
 abilities, albeit at levels insufficient to mitigate DHA deficiencies
 associated with urban foraging and shifting marine ecosystems.
description: # Data from: Biosynthesis of long-chain omega-3 fatty acids in a
 generalist seabird Metadata for dataset file: Lamarre&Wilson_2025_RBGU
 ALA convert Accompanying Rcode file using this
 dataset: Lamarre_Wilson_2025_ALA_convert.R Data collected by: Jessika
 Lamarre and David Wilson Author Information A. Corresponding author Name:
 Jessika Lamarre Institution: Memorial University of Newfoundland Email:
 [jlamarre@mun.ca](mailto:jlamarre@mun.ca) B. Co-author Name: David Wilson
 Institution: Memorial University of Newfoundland Email:
 [dwilson@mun.ca](mailto:dwilson@mun.ca) Format: file format is comma
 separated (.csv) Data: | Variable | Description | | :----------- |
 :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | ID | Unique identifier of each hatchling, of type of oil supplement administered (Flaxseed\_oil or Coconut\_oil), or of diet provided in captivity (Feed | | Colony | Hatched at the urban colony (Kellys\_Island) or the rural colony (Salmonier); Not applicable (N/A) for the types of oil supplement administered and the diet provided in captivity | | Tissue | Tissues collected from the chicks (Cerebral\_hemispheres or Liver), type of oil supplement administered (Flaxseed\_oil or Coconut\_oil), or diet provided in captivity (Feed) | | Treatment | Either received the ALA supplementation (ALA-d13C tracer + flaxseed oil; Supplement\_ALA) or they received a caloric equivalent devoid of omega-3s or tracer (coconut oil; Control). The flaxseed oil supplement are labelled as Supplement\_ALA and the coconut oil supplement is labelled as Control | | Wt\_d0 | Mass of hatchling (g) at collection; Not applicable (N/A) for the types of oil supplement administered and the diet provided in captivity | | Wt\_d1 | Mass of hatchling (g) 24hrs after having been brought into captivity; Not applicable (N/A) for the types of oil supplement administered and the diet provided in captivity | | Wt\_d2 | Mass of hatchling (g) 48hrs after having been brought into captivity; Not applicable (N/A) for the types of oil supplement administered and the diet provided in captivity | | Wt\_d3 | Mass of hatchling (g) 72hrs after having been brought into captivity; Not applicable (N/A) for the types of oil supplement administered and the diet provided in captivity | | ALA\_d13C | d13C signature (‰) of FAME alpha-linolenic acid (C18:3w3; ALA) corrected for the addition of carbon by MeOH during transmethylation (d13C signature of -28.21); Not Available (N/A) for individuals with ALA tissue concentration &gt;1.5% of the total fatty acids detected | | SA\_d13C | d13C signature (‰) of FAME stearidonic acid (C18:4w3) corrected for the addition of carbon by MeOH during transmethylation (d13C signature of -28.21); Not Available (N/A) for individuals with SA tissue concentration &gt;1.5% of the total fatty acids detected | | EPA\_d13C | d13C signature (‰) of FAME eicosapentaenoic acid (C20:5w3) corrected for the addition of carbon by MeOH during transmethylation (d13C signature of -28.21); Not Available (N/A) for individuals with EPA tissue concentration &gt;1.5% of the total fatty acids detected | | DPA\_d13C | d13C signature (‰) of FAME docosapentaenoic acid (C22:5w3) corrected for the addition of carbon by MeOH during transmethylation (d13C signature of -28.21); Not Available (N/A) for individuals with DPA tissue concentration &gt;1.5% of the total fatty acids detected | | DHA\_d13C | d13C signature (‰) of FAME docosahexaenoic acid (C22:6w3) corrected for the addition of carbon by MeOH during transmethylation (d13C signature of -28.21); Not Available (N/A) for individuals with DHA tissue concentration &gt;1.5% of the total fatty acids detected | | C14:0 | Relative concentration of the fatty acid C14:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | C14:1 | Relative concentration of the fatty acid C14:1 in the chicks tissues, expressed as percentage of total identified fatty acids | | C15:0 | Relative concentration of the fatty acid C15:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | C15:1 | Relative concentration of the fatty acid C15:1 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:0 | Relative concentration of the fatty acid C16:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:1w11 | Relative concentration of the fatty acid C16:1w11 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:1w9 | Relative concentration of the fatty acid C16:1w9 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:1w7 | Relative concentration of the fatty acid C16:1w7 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:1w5 | Relative concentration of the fatty acid C16:1w5 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:2w6 | Relative concentration of the fatty acid C16:2w6 in the chicks tissues, expressed as percentage of total identified fatty acids | | C17:0 | Relative concentration of the fatty acid C17:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:3w4 | Relative concentration of the fatty acid C16:3w4 in the chicks tissues, expressed as percentage of total identified fatty acids | | C17:1 | Relative concentration of the fatty acid C17:1 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:4w3 | Relative concentration of the fatty acid C16:4w3 in the chicks tissues, expressed as percentage of total identified fatty acids | | C16:4w1 | Relative concentration of the fatty acid C16:4w1 in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:0 | Relative concentration of the fatty acid C18:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:1w11 | Relative concentration of the fatty acid C18:1w11 in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:1w9 | Relative concentration of the fatty acid C18:1w9 in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:1w7 | Relative concentration of the fatty acid C18:1w7 in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:1w6 | Relative concentration of the fatty acid C18:1w6 in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:1w5 | Relative concentration of the fatty acid C18:1w5 in the chicks tissues, expressed as percentage of total identified fatty acids | | LA | Relative concentration of the fatty acid C18:2w6 (linoleic acid; LA) in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:2w4 | Relative concentration of the fatty acid C18:2w4 in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:3w4 | Relative concentration of the fatty acid C18:3w4 in the chicks tissues, expressed as percentage of total identified fatty acids | | ALA | Relative concentration of the fatty acid C18:3w3 (alpha-linolenic acid; ALA) in the chicks tissues, expressed as percentage of total identified fatty acids | | SA | Relative concentration of the fatty acid C18:4w3 (stearidonic acid; SA) in the chicks tissues, expressed as percentage of total identified fatty acids | | C18:4w1 | Relative concentration of the fatty acid C18:4w1 in the chicks tissues, expressed as percentage of total identified fatty acids | | C20:0 | Relative concentration of the fatty acid C20:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | C20:1w11 | Relative concentration of the fatty acid C20:1w11 in the chicks tissues, expressed as percentage of total identified fatty acids | | C20:1w9 | Relative concentration of the fatty acid C20:1w9 in the chicks tissues, expressed as percentage of total identified fatty acids | | C20:1w7 | Relative concentration of the fatty acid C20:1w7 in the chicks tissues, expressed as percentage of total identified fatty acids | | C20:2w6 | Relative concentration of the fatty acid C20:2w6 in the chicks tissues, expressed as percentage of total identified fatty acids | | ARA | Relative concentration of the fatty acid C20:4w6 (arachidonic acid; ARA) in the chicks tissues, expressed as percentage of total identified fatty acids | | ETE | Relative concentration of the fatty acid C20:3w3 (eicosatrienoic acid; ETE) in the chicks tissues, expressed as percentage of total identified fatty acids | | ETA | Relative concentration of the fatty acid C20:4w3 (eicosatetraenoic acid; ETA) in the chicks tissues, expressed as percentage of total identified fatty acids | | EPA | Relative concentration of the fatty acid C20:5w3 (eicosapentaenoic acid; EPA) in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:0 | Relative concentration of the fatty acid C22:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:1w11(13) | Relative concentration of the fatty acid C22:1w11(13) in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:1w9 | Relative concentration of the fatty acid C22:1w9 in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:1w7 | Relative concentration of the fatty acid C22:1w7 in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:2w6 | Relative concentration of the fatty acid C22:2w6 in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:4w6 | Relative concentration of the fatty acid C22:4w6 in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:3w3 | Relative concentration of the fatty acid C22:3w3 in the chicks tissues, expressed as percentage of total identified fatty acids | | DPA\_n6 | Relative concentration of the fatty acid C22:5w6 (n-6 docosapentaenoic acid; DPA\_n6) in the chicks tissues, expressed as percentage of total identified fatty acids | | C22:4w3 | Relative concentration of the fatty acid C22:4w3 in the chicks tissues, expressed as percentage of total identified fatty acids | | DPA | Relative concentration of the fatty acid C22:5w3 (docosapentaenoic acid; DPA) in the chicks tissues, expressed as percentage of total identified fatty acids | | C24:0 | Relative concentration of the fatty acid C24:0 in the chicks tissues, expressed as percentage of total identified fatty acids | | DHA | Relative concentration of the fatty acid C22:6w3 (docosahexaenoic acid; DHA) in the chicks tissues, expressed as percentage of total identified fatty acids | | C24:1 | Relative concentration of the fatty acid C24:1 in the chicks tissues, expressed as percentage of total identified fatty acids |