Omega-3 fatty acids accelerate fledging in an avian marine predator: a potential role of cognition.

Jessika Lamarre,Sukhinder Kaur Cheema,Gregory J Robertson,David R Wilson

doi:10.1242/jeb.235929

Abstract

ABSTRACTConsuming omega-3 fatty acids (n-3 LCPUFAs) during development improves cognition in mammals, but the effect remains untested in other taxa. In aquatic ecosystems, n-3 LCPUFAs are produced by phytoplankton and bioaccumulate in the food web. Alarmingly, the warming and acidification of aquatic systems caused by climate change impair n-3 LCPUFA production, with an anticipated decrease of 80% by the year 2100. We tested whether n-3 LCPUFA consumption affects the physiology, morphology, behaviour and cognition of the chicks of a top marine predator, the ring-billed gull. Using a colony with little access to n-3 LCPUFAs, we supplemented siblings from 22 fenced nests with contrasting treatments from hatching until fledging; one sibling received n-3 LCPUFA-rich fish oil and the other, a control sucrose solution without n-3 LCPUFAs. Halfway through the nestling period, half the chicks receiving fish oil were switched to the sucrose solution to test whether n-3 LCPUFA intake remains crucial past the main growth phase (chronic versus transient treatments). Upon fledging, n-3 LCPUFAs were elevated in the blood and brains of chicks receiving the chronic treatment, but were comparable to control levels among those receiving the transient treatment. Across the entire sample, chicks with elevated n-3 LCPUFAs in their tissues fledged earlier despite their morphology and activity levels being unrelated to fledging age. Fledging required chicks to escape fences encircling their nest. We therefore interpret fledging age as a possible indicator of cognition, with chicks with improved cognition fledging earlier. These results provide insight into whether declining dietary n-3 LCPUFAs will compromise top predators' problem-solving skills, and thus their ability to survive in a rapidly changing world.

Highlights

IntroductionN-3 LCPUFAs provide precursors for myelin sheath production (Feltham et al, 2019), ensuring the synaptic health and plasticity of the brain (review by Yang et al, 2018)
Incorporation of n-3 LCPUFAs into red blood cells (RBCs) and brain tissue Chicks supplemented with fish oil each day between hatching and fledging had significantly higher levels of docosahexaenoic acid (DHA) in their RBCs than chicks that were supplemented with a sucrose solution control during the same period, as revealed by the analysis of blood samples taken at 15 and 36 dph (Table 1, Fig. 2)
We investigated the positive effect of n-3 LCPUFA supplementation on the cognition of ring-billed gull nestlings in a population feeding primarily on terrestrial food sources with access to little to no n-3 LCPUFAs

Summary

Introduction

N-3 LCPUFAs provide precursors for myelin sheath production (Feltham et al, 2019), ensuring the synaptic health and plasticity of the brain (review by Yang et al, 2018). Through their anti-inflammatory actions, they maintain high blood flow to the brain (Bazinet and Layé, 2014; Calder, 2015). For example, n-3 LCPUFAs accumulate rapidly in the brains of nestlings (Price et al, 2018; Speake and Wood, 2005; Twining et al, 2018a), yet it remains unknown whether dietary restriction of n-3 LCPUFAs impairs avian cognition

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