Validation of the use of phenylhydrazine hydrochloride (PHZ) for experimental manipulation of haematocrit and plasma haemoglobin in birds

Williams, Tony; Fronstin, Raime B.; Otomo, Aki; Wagner, Emily

doi:10.1111/j.1474-919x.2011.01195.x

Cited by 16 publications

(29 citation statements)

References 41 publications

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“…Therefore, the pattern of the relationship between haematocrit and Ṁ sum seemed to parallel that observed between pectoral muscle size and Ṁ sum . The parabolic shape in the relationship between Ṁ sum and haematocrit is consistent with the idea that beyond a certain level, the benefit of increasing oxygen carrying capacity is counterbalanced by the disadvantage of elevated blood viscosity (Schuler et al, 2010;Williams et al, 2012). Therefore, it could be that chickadees have an optimal haematocrit level that maximizes their heat production capacity and cold endurance, and given that heart mass fluctuates seasonally in small wintering passerines (e.g.…”

Section: Discussionsupporting

confidence: 59%

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Phenotype manipulations confirm the role of pectoral muscles and haematocrit in avian maximal thermogenic capacity

Petit

Vézina

2013

Journal of Experimental Biology

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In small resident bird species living at northern latitudes, winter cold acclimatization is associated with an increase in pectoral muscle size and haematocrit level, and this is thought to drive the seasonal increase in summit metabolic rate (Ṁ sum , a measure of maximal shivering thermogenic capacity). However, evidence suggesting that pectoral muscle size influences Ṁ sum is correlational and the link between haematrocrit level and Ṁ sum remains to be demonstrated. We experimentally tested the relationship between pectoral muscle size and Ṁ sum by manipulating muscle size using a feather clipping protocol in free-living wintering black-capped chickadees (Poecile atricapillus). This also allowed us to investigate the link between haematocrit and thermogenic capacity. After a first series of measures on all birds, we cut half of the flight feathers of experimental individuals (N=14) and compared their fat and pectoral muscle scores, Ṁ sum and haematocrit level at recapture with their previous measures and with those of control birds (N=17) that were captured and recaptured at comparable times. Results showed that: (1) experimental birds developed larger pectoral muscles than control individuals and (2) mass-independent Ṁ sum was up to 16% higher in birds expressing large pectoral muscles. Ṁ sum was also positively correlated with haematocrit, which was not affected by the experimental manipulation. These findings demonstrate that, for a given body mass, large pectoral muscles are associated with a higher Ṁ sum in black-capped chickadees and that oxygen carrying capacity likely supports thermogenesis in this species.

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Section: Discussionsupporting

confidence: 59%

“…As far as we know, this is the first demonstration of the relationship between maximal thermogenic capacity and haematocrit in birds. However, this link remains correlative, and experimental manipulations of haematocrit levels (Williams et al, 2012) should be conducted to confirm its role in supporting thermogenesis.…”

Section: Discussionmentioning

confidence: 99%

Phenotype manipulations confirm the role of pectoral muscles and haematocrit in avian maximal thermogenic capacity

Petit

Vézina

2013

Journal of Experimental Biology

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“…; Williams et al . ). PHZ was administered to females at one of two time points: (i) upon removal of a first clutch to determine effects of Hct reduction on the ability of females to produce a replacement clutch and (ii) during late incubation of a first unmanipulated clutch, to determine whether reproductive Hct reduction, which can last throughout chick rearing (Williams et al .…”

Section: Introductionmentioning

confidence: 97%

Experimental reduction of haematocrit affects reproductive performance in European starlings

2015

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Summary Given the function of haemoglobin and observed increases in haematocrit during periods of increased energetic demands, haematocrit and haemoglobin are assumed to be related to aerobic capacity. Reductions in haematocrit and haemoglobin during reproduction are similar in magnitude to increases associated with aerobically demanding activities, and therefore, we sought to investigate whether these reductions in haematology have consequences for reproductive performance. We analysed associations between natural variation in haematology in free‐living European starlings (Sturnus vulgaris) and reproductive performance. To test whether transient reductions in haematology during different stages of reproduction (egg production and late incubation/early chick rearing) affected measures of reproductive performance, we also manipulated haematology using phenylhydrazine (PHZ), which lyses red blood cells. To investigate effects of reductions of haematology during egg‐laying, we treated females with PHZ or saline (control) upon completion of their unmanipulated first clutch and removed eggs to induce the production and rearing of a replacement clutch. To investigate effects of reductions of haematology during chick rearing, we treated females during incubation of the unmanipulated first clutch and then monitored the subsequent hatching and rearing of the clutch. Individuals with higher haematocrit and haemoglobin initiated nesting earlier. Furthermore, higher haemoglobin levels during incubation were associated with a greater number of chicks fledged. PHZ treatment prior to egg production resulted in a significant delay in the laying of replacement clutches, but had no effect on provisioning rate or the size or number of chicks fledged. PHZ treatment during incubation and early chick rearing resulted in decreased hatchling mass in all years and a decrease in the size and number of fledglings in one of 2 years. The year that the effect of PHZ was observed appeared to be a particularly difficult year, as hatchling mass, brood size at hatching and at fledging were low among control females compared to other years. Our results suggest that a reduction in haematology during reproduction can be functionally significant, but that these costs are context‐dependent.

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“…Blood samples were analysed for haematocrit and haemoglobin concentration as in the study by Williams et al . (). An aliquot of these samples were sent to Viaguard Accu‐Metrics (Toronto, Ontario) for sexing by PCR.…”

Section: Methodsmentioning

confidence: 97%

Physiological maturity at a critical life‐history transition and flight ability at fledging

2016

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Summary Developmental maturity (e.g. body condition, body mass) at major life‐history transitions is known to affect fitness across a wide range of taxa. Fledging (leaving the nest), a major life‐history transition in birds, is associated with high post‐fledging mortality and is widely assumed to be related to poor initial flight ability of fledglings, which, in turn, might be related to developmental maturity at fledging. We investigated individual variation in developmental maturity of both somatic and physiological traits at this critical life‐history transition in different ecological contexts (year, first or second broods) to determine the importance of physiological traits related to oxygen‐carrying capacity (haematocrit, haemoglobin) for individual variation in initial flight ability at fledging. Haemoglobin concentration and haematocrit at fledging had much higher variance than somatic traits and were more variable across ecological contexts. Furthermore, fledgling haemoglobin concentration was the least developmentally mature of all traits (on average, only 78% of adult concentration). Fledglings from second broods, which are known to have lower post‐fledging survival, were less developmentally mature than fledglings from first broods for all traits (except tarsus), with haematocrit and haemoglobin concentration being the most developmentally immature traits (in first vs. second broods, haematocrit: 47·1% vs. 40·9%; haemoglobin: 13·3 vs. 11·6 g dL−1). Models predicting individual variation in two aspects of initial flight ability (total energy gain, take‐off angle) were significantly improved when physiological traits (in particular haemoglobin) were incorporated into models based on somatic traits. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12777/suppinfo is available for this article.

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Validation of the use of phenylhydrazine hydrochloride (PHZ) for experimental manipulation of haematocrit and plasma haemoglobin in birds

Cited by 16 publications

References 41 publications

Phenotype manipulations confirm the role of pectoral muscles and haematocrit in avian maximal thermogenic capacity

Phenotype manipulations confirm the role of pectoral muscles and haematocrit in avian maximal thermogenic capacity

Experimental reduction of haematocrit affects reproductive performance in European starlings

Physiological maturity at a critical life‐history transition and flight ability at fledging

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