Measuring ketones in the field: rapid and reliable measures of β‐hydroxybutyrate in birds

Abstract

Ketone bodies such as β‐hydroxybutyrate are important indicators of metabolic condition in birds and are linked to a suite of ecologically relevant factors including migratory decision‐making, hunger level and ectoparasite load. Portable point‐of‐care (POC) devices designed to measure ketones in humans offer a cheap and easy solution to field physiologists in comparison with previous laboratory methods; however, their accuracy for use in birds has received scant attention. Here, we assessed the accuracy of a POC ketone meter (FreeStyle Precision Neo, Abbott, IL, USA) using samples from intermittently fed Red Junglefowl Gallus gallus. Although the device overestimated ketone levels in comparison with laboratory‐derived values, random error was low and laboratory vs. device values correlated well, indicating that the Precision Neo is of sufficient accuracy for use in the field and is a pragmatic choice for avian physiologists.

Ketone body levels in wintering great tits Parus major in sites differing in artificial food availability

“…The birds were released immediately after sampling. As described by Lindholm et al (2019 ), the device overestimated ketone levels compared to laboratory-derived values; nevertheless, laboratory vs. device values correlated well, indicating that the Optium Xido Neo is accurate enough and to be used in field studies. In nine cases in the parkland area values higher than the device measurement range (0.0–8.0 mM/l), we assumed a value of 8.1 mM/l for calculations.…”

“… Lindholm et al (2019) validated a point-of-care (POC) device for use in birds and found strong agreement of the obtained measurements of the levels of ketone bodies between the device and the widely used standard laboratory methodology. Lindholm et al (2019) studied indoor-raised red junglefowl ( Gallus gallus ), kept under a strict feeding regime.…”

“… Lindholm et al (2019) validated a point-of-care (POC) device for use in birds and found strong agreement of the obtained measurements of the levels of ketone bodies between the device and the widely used standard laboratory methodology. Lindholm et al (2019) studied indoor-raised red junglefowl ( Gallus gallus ), kept under a strict feeding regime. Since their study validated the application of the device in the assessment of ketone bodies in avian species, we decided in our study to measure blood ketone concentrations by using the same type of POC device in wild species, wintering great tit ( Parus major ).…”

“…The devices have already been used in the case of domestic animals such as sheep or dairy cows ( Hornig et al , 2013 ; Geishauser et al , 2001 ; Iwersen et al ., 2013 ; Xu et al , 2017 ) and have also been used successfully in wild bat species ( Boyles et al , 2016 ). However, portable devices have rarely been used to measure ketones in wild birds and we are only aware of three studies so far ( Azeredo et al , 2016 ; Sommers et al , 2017 ; Lindholm et al , 2019 ).…”

Intermittent fasting in chickens : Physiological mechanisms and welfare implications for broiler breeders

“…The time a chicken spends in Phase I largely depends on its hepatic energy reserves (muscle glycogen does not appear to contribute much), with ad libitum-fed broilers depleting their liver glycogen reserves in around 6 h (Warriss et al, 1988), but time courses can vary widely between different chicken strains and feeding strategies. For example, we have seen an approximately 9-fold increase in βHB after 40 h of fasting in 4-week-old Red Junglefowl (Lindholm et al, 2019), while 12-week-old broiler breeders only exhibited a 1.6-fold increase in the same time ( Figure 5).…”