Impacts of food-based enrichment on behaviour and physiology of male greater rheas (Rhea Americana, Rheidae, Aves)

Cristiano Schetini De Azevedo,Priscila Viau,Márcia Fontes Figueiredo Lima,Robert John Young

doi:10.11606/1807-0205/2019.59.11

Abstract

Distress can be defined as a biological response of an individual to long-term threats to its homeostasis and it should be avoided from an animal welfare perspective. High levels of stress hormones and the expression of abnormal behaviours are responses normally observed in distressed animals. Captive environments can provoke distress, especially when inappropriate stimuli are provided to the animals. The concomitant use of behavioural and non-invasive hormonal measures is a means to evaluate captive animal welfare. Environmental enrichment is a tool that can reduce distress and minimize the expression of abnormal behaviour in captive animals. The aim of this study was to evaluate greater rheas’ responses (behavioral and hormonal) to food-based enrichment. Three birds from the Belo Horizonte Zoo, Brazil were studied. The study was divided into three phases (baseline, enrichment and post-enrichment): fruits scattered around the birds’ enclosure were used as enrichment. Behaviour and faecal sampling were undertaken in all phases of the study. Abnormal behaviours and faecal glucocorticoid metabolites (GCM) levels showed significant reduction during the environmental enrichment phase, and a significative positive correlation between GCM production and abnormal pacing was observed. From the results of this study, we conclude that the use of food as environmental enrichment should be encouraged because of its positive effects on animal welfare. Besides, studies with larger groups of greater rheas, with individuals of both sexes, should also be encouraged to evaluate if the results found in this pilot study are consistent and can be generalized to the species.

Highlights

A restricted or unstimulating environment increases the probability that an animal will develop abnormal behaviour (Kelling & Jensen, 2009)
Environmental enrichment is a set of techniques designed to improve the quality of life of animals kept in captivity, seeking to identify and provide the necessary environmental stimuli for their physical and psychological welfare (Shepherdson et al, 1998; Young, 2003)
Abnormal behaviours eating faeces and pacing showed the same responses for the environmental enrichment phase: both decreased significantly from the baseline to the enrichment phase; eating faeces showed a slight increase in post-enrichment phase and pacing continued to decrease during post-enrichment phase (Fig. 2)

Summary

Introduction

A restricted or unstimulating environment increases the probability that an animal will develop abnormal behaviour (Kelling & Jensen, 2009). Animals that exhibit abnormal behaviour normally have a lower level of welfare and frequently higher levels of stress (Young, 2003; Broom & Molento, 2004). Foodbased enrichment has been proven to be effective in stimulating animals and reducing distress, because the acquisition of food is a highly-motivated behaviour and is self-rewarding (Young, 2003; Vasconcellos et al, 2009; Clark & Melfi, 2012; Azevedo et al, 2013a)

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Discussion

Conclusion