A fruit diet rather than invertebrate diet maintains a robust innate immunity in an omnivorous tropical songbird

Autor: Maurine W. Dietz, Chima Josiah Nwaogu, Annabet Galema, B. Irene Tieleman, Will Cresswell
Přispěvatelé: University of St Andrews. School of Biology, University of St Andrews. Centre for Biological Diversity, University of St Andrews. Scottish Oceans Institute, University of St Andrews. Institute of Behavioural and Neural Sciences, University of St Andrews. St Andrews Sustainability Institute, Tieleman lab, Dietz group
Rok vydání: 2020
Předmět:
0106 biological sciences
LIFE-HISTORY
QH301 Biology
Path analyses
PROTEIN
POSTNUPTIAL MOLT
Environmental change
immunomodulation
01 natural sciences
Songbirds
Nutrient
MEDIATES TRADE-OFFS
ECOLOGICAL IMMUNOLOGY
Physiological Ecology
R2C
2. Zero hunger
biology
life-history trade-offs
NATURAL ANTIBODIES
environmental change
Haemolysis
Omnivore
BDC
Moulting
Research Article
Vegetarians
path analyses
Zoology
WHITE-CROWNED SPARROWS
010603 evolutionary biology
Immunomodulation
QH301
Life-history trade-offs
Immune system
Immunity
Animals
Ecology
Evolution
Behavior and Systematics
nutrient limitation
Innate immune system
BIRDS
010604 marine biology & hydrobiology
vegetarians
DAS
biology.organism_classification
Invertebrates
life‐history trade‐offs
Immunity
Innate
Diet
Songbird
Fruit
Nutrient limitation
OXIDATIVE DAMAGE
Animal Science and Zoology
REPRODUCTIVE EFFORT
Zdroj: The Journal of Animal Ecology
Journal of Animal Ecology, 89(3), 867-883. Wiley
ISSN: 1365-2656
0021-8790
Popis: Diet alteration may lead to nutrient limitations even in the absence of food limitation, and this may affect physiological functions, including immunity. Nutrient limitations may also affect the maintenance of body mass and key life‐history events that may affect immune function. Yet, variation in immune function is largely attributed to energetic trade‐offs rather than specific nutrient constraints.To test the effect of diet on life‐history traits, we tested how diet composition affects innate immune function, body mass and moult separately and in combination with each other, and then used path analyses to generate hypotheses about the mechanistic connections between immunity and body mass under different diet compositions.We performed a balanced parallel and crossover design experiment with omnivorous common bulbuls Pycnonotus barbatus in out‐door aviaries in Nigeria. We fed 40 wild‐caught bulbuls ad libitum on fruits or invertebrates for 24 weeks, switching half of each group between treatments after 12 weeks. We assessed innate immune indices (haptoglobin, nitric oxide and ovotransferrin concentrations, and haemagglutination and haemolysis titres), body mass and primary moult, fortnightly. We simplified immune indices into three principal components (PCs), but we explored mechanistic connections between diet, body mass and each immune index separately.Fruit‐fed bulbuls had higher body mass, earlier moult and showed higher values for two of the three immune PCs compared to invertebrate‐fed bulbuls. These effects were reversed when we switched bulbuls between treatments after 12 weeks. Exploring the correlations between immune function, body mass and moult, showed that an increase in immune function was associated with a decrease in body mass and delayed moult in invertebrate‐fed bulbuls, while fruit‐fed bulbuls maintained body mass despite variation in immune function. Path analyses indicated that diet composition was most likely to affect body mass and immune indices directly and independently from each other. Only haptoglobin concentration was indirectly linked to diet composition via body mass.We demonstrated a causal effect of diet composition on innate immune function, body mass and moult: bulbuls were in a better condition when fed on fruits than invertebrates, confirming that innate immunity is nutrient specific. Our results are unique because they show a reversible effect of diet composition on wild adult birds whose immune systems are presumably fully developed and adapted to wild conditions—demonstrating a short‐term consequence of diet alteration on life‐history traits.
The authors results confirm that innate immunity is nutrient specific, but they are unique because the authors show an experimentally reversible effect of diet composition on wild adult birds whose immune systems are presumably fully developed and adapted to wild conditions—demonstrating a short‐term consequence of diet alteration in natural systems.
Databáze: OpenAIRE
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