Specific Appetite for Carotenoids in a Colorful Bird

Juan Carlos Senar,Anders Pape Møller,Juan José Negro,Juli Broggi,Esa Hohtola,Iker Ruiz,Tom Pizzari

doi:10.1371/journal.pone.0010716

Abstract

BackgroundSince carotenoids have physiological functions necessary for maintaining health, individuals should be selected to actively seek and develop a specific appetite for these compounds.Methodology/Principal FindingsGreat tits Parus major in a diet choice experiment, both in captivity and the field, preferred carotenoid-enriched diets to control diets. The food items did not differ in any other aspects measured besides carotenoid content.Conclusions/SignificanceSpecific appetite for carotenoids is here demonstrated for the first time, placing these compounds on a par with essential nutrients as sodium or calcium.

Highlights

Mineral and nutrient appetite is defined as the motivation to seek or choose specific mineral/nutrient-containing items [1]
In captivity choice tests great tits preferentially chose those mealworms that had been experimentally enriched with carotenoids over control mealworms (Wilcoxon signed rank test, T = 66.5, p,0.05) (Figure 1a), despite them not differing in appearance or any other nutritional aspect than carotenoid content (Table 1)
While there was no significant difference from the null expectation for the first mealworm chosen (56% choosing the high carotenoid treatment; log-likelihood ratio test, G = 0.48, d.f. = 1, P = 0.85), this preference subsequently increased to 88% for mealworms with high carotenoid levels (G = 22.50, d.f. = 1, P,0.001)

Summary

Introduction

Mineral and nutrient appetite is defined as the motivation to seek or choose specific mineral/nutrient-containing items [1]. An specific appetite has been shown, in many different animal species, for sodium [2], calcium [1] and even amino acids [3]. Such ‘‘nutritional wisdom’’ allows animals to regulate their diet choice to satisfy their physiological needs [1]. Since carotenoids cannot be synthesised by animals and must be acquired from food, specific appetite for carotenoids should be selectively favored. This should be even more strongly selected in colorful carotenoid-based bird species, in which additional allocation of these compounds for feather pigmentation demands an even larger consumption of carotenoids. Since carotenoids have physiological functions necessary for maintaining health, individuals should be selected to actively seek and develop a specific appetite for these compounds

Methods

Results

Conclusion