Hematological parameters of a Neotropical wild frog population, with a phylogenetic perspective on blood cell composition in Anura

Abstract

Hematological parameters can provide key information to an animal health status. However, this information is usually hard to obtain. Here, we described hematological parameters of Leptodactylus podicipinus in the Brazilian Pantanal. We measured red blood cell morphometrics, erythrogram, and leukogram. We also tested for phylogenetic signal in erythrogram and leukogram of 48 frog species from 15 families, testing if body size explains their variation. Lymphocytes were the most abundant leukocytes (> 60%) in Leptodactylus podicipinus, followed by neutrophils (∼10%). Given that L. podicipinus is an abundant and widely distributed species in central Brazil, knowing its hematological pattern can help stablish a baseline and improve its use as a bioindicator of environmental degradation. Mean corpuscular hemoglobin and value contributed more to the phylomorphospace of erythrogram, in which Leptodactylus spp. and Hypsiboas raniceps had lower values of these variables, while Bufotes viridis and Hyla arborea had high values. The phylogenetic signal was spread throughout the dimensions of leukogram phylomorphospace. The variables that most contributed to it were total leukocytes counts, lymphocytes and neutrophils. We also found a moderate phylogenetic signal for both the erythrogram and leukogram. Accordingly, body size accounted for a low proportion of variation in both the leukogram (4.7%) and erythrogram (0.57%). By combining phylogenetic comparative methods with hematological parameters, our results add a new perspective on the evolution of blood cell physiology in frogs.

Morphology and cytochemical patterns of peripheral blood cells of tiger frog (Rana rugulosa)

“…In this study, five types of leukocytes: neutrophils, eosinophils, basophils, monocytes and lymphocytes were observed respectively in tiger frog peripheral blood, which was in accord with those described in neotropical wild frog ( Leptodactylus podicipinus ) ( Franco-Belussi et al, 2021 ), American bullfrog and African clawed frog ( Bricker, Raskin & Densmore, 2012 ), while most of fish lack basophils ( Fang et al, 2014 ; Zheng et al, 2015 ). The morphology of neutrophils, eosinophils and basophils in tiger frogs were usually round, which was consistent with those of other reported amphibians and mammals ( Salakij et al, 2005 ; Prihirunkit et al, 2007 ; Gutierre et al, 2008 ; Bricker, Raskin & Densmore, 2012 ).…”

Multiple morphophysiological responses of a tropical frog to urbanization conform to the pace-of-life syndrome

“…We only collected males due to the sampling strategy employed, which used acoustic signals to locate individuals. Previous studies found negligible differences between sexes in terms of haematological parameters ( Franco-Belussi et al, 2022 and references cited therein).…”

“…5 ). The model explained a substantial amount of variance (Nagelkerke's R 2 = 0.67), with site individually explaining 62.63% of the variance, while age explained 37.37% (see Franco-Belussi et al, 2023 ). The overall mean (±SD) of abnormalities in the urban (6.09 ± 2.47) was twice larger than in the rural population (3 ± 1.70).…”

“…Then, we took several linear morphometric measurements from erythrocytes. Specifically, cell and nuclear volume, cell and nuclear area and nucleus/cytoplasm ratio in 50 cells per animal (see Franco-Belussi et al, 2022 for more details on methods). To describe the leukocyte profile of the two populations, we counted 100 leukocytes in each blood smear to establish the percentage of each leukocyte found in frogs (differential leukocyte count): lymphocytes, basophils, neutrophils, monocytes, thrombocytes and eosinophils ( Allender and Fry, 2008 ; Davis et al, 2008 ).…”

“…Before calculating trajectory attributes, we first built multivariate linear models (two-way MANOVAs) using all PCs for each data set as response variables, modelled as a function of site (factor with two levels) and age (ordered factor with three levels), including their interaction. Residual diagnostics was conducted by visually inspecting q-q plots and residual versus fitted (see Franco-Belussi et al, 2023 ). No model violated assumptions.…”