Free-living Capybaras (Hydrochoerus hydrochaeris) in an Urban Area in Brazil - Biochemical and Hematological Parameters

Abstract

Background: Capybaras have found favorable conditions for survival and reproduction in green urban environments. In recent years, the population of these large rodents has been increasingly abundant in several brazilian cities such as Uberlândia, a municipality of the southeastern region with a Cerrado biome. Capybaras are important in the Brazilian Spotted Fever epidemiological chain, by amplifying infection rates of the vector population. However, knowledge of this host´s physiology is scarce. Thus, the aim of this work was to describe hematological and biochemical parameters of free-living capybaras groups in urbanized areas in the city of Uberlândia, Minas Gerais State, Brazil.Materials, Methods & Results: Capybaras were captured in 4 different locations of Uberlândia city, Minas Gerais state, including 1 Condominium (P1), 1 Private Market Garden (P2), 1 Private Club (P3) and 1 Municipal Park (P4). The animals were baited into an octagonal iron corral and chemically contained with anesthetic darts. After sedated, blood was collected from the femoral vein in tubes with and without EDTA. Biochemical evaluation, hematological analysis with differential leukocyte counts and search for Dirofilaria sp. were done. The blood count and biochemistry values obtained from animals of different ages, sex and sectors (P1, P2, P3 and P4) were submitted to the Shapiro-Wilk normality test, considering 95% significance. Values that had a normal distribution were subjected to ANOVA tests followed by Student's t-test. Values that did not follow normality were submitted to the Kruskal-Wallis test, to obtain a P-value, with a significance level of 95%. A total of 19 capybaras were captured: 4 in P1, 6 in P2, 4 in P3 and 5 in P4. From the 19 animals, 13 were females (68.42%) and 6 were males (31.57%), 12 adults (63.15%) and 7 juveniles (36.84%). Apart from occasional skin scars and moderate to intense Ambyomma spp. tick infestations, all captured animals were healthy on a broad examination. From 5 animals captured in P4, despite the use of anticoagulant, blood from 4 animals clotted fast. No microfilariae were found in the thick drop test in any of the 19 animals sampled, and in 2 adult female capybaras captured in P1, Kurloff cells were observed. Hematological and biochemical values presented no major differences when comparing sex and age. Nevertheless, differences in liver and kidney profile were observed between the capybara groups, including ALT, alkaline phosphorus, BUN and creatinine.Discussion: Blood from 4 animals clotted fast, despite the use of EDTA tubes. Blood clotting of samples with anticoagulant in this work could be associated with some physiological features inherent to capybaras. Many attempts were required to obtain enough blood from each individual due to the rapid hemostasis, what come in accordance with reports in literature. Kurloff cells were observed in 2 adult female capybaras captured in P1, which can be found in peripheral blood of female rodents during follicular phase of estrous cycle. Hematological and biochemical values differences in liver enzymes such as ALT and alkaline phosphorus, and kidney profile enzymes including BUN and creatinine could be associated to capture stress or dietetic variation between groups. Despite statistical relevant, the values were still in accordance with other works, although comparisons should be done with caution since various environments exert a diverse array of stimulus upon the animals such as parasitic, infective, stress, nutritional, social and undoubtedly blood parameters mirror them. In conclusion, this work contributes to the standardization of free-living capybaras' physiological parameters in urban areas.Keywords: capybaras, physiological parameters, enzymatic parameters, green urban environment, capture stress, fauna, biomes.

Skull of Capybara (Hydrochoerus hydrochaeris) - Morphometric Parameters

“…The capybara (Hydrochoerus hydrochaeris) is the largest rodent in the world and belongs to the order Rodentia, family Caviidae, and subfamily Hydrochoerinae [15,27]. They are herbivorous animals with semi-aquatic, gregarious and territorial habits [14,17,20,21,26]. The capybara body is large and heavy with body mass averages 48.9 kg and ranges from 35 to 65.5 kg [15].…”

“…The scientific interest in capybaras has increased in recent years because they are being found in anthropogenic areas, such as urban and peri-urban parks close to water sources. These rodents are considered the main host for all parasitic stages of tick of the spotted-fever by Rickettsia rickettsii infection [11,25,26], and this has great Public Heath importance in Brazil due to its high fatality rates in humans [12,19].…”

Mandibular morphometry applied to local anaesthetic blockage in the capybara (Hydrochoerus hydrochaeris)

“…The capybara ( Hydrochoerus hydrochaeris ) is the largest Neotropical rodent and belongs to the order Rodentia, family Caviidae and subfamily Hydrochoerinae (Mones & Ojasti, 1986; Woods & Kilpatrick, 2005). This rodent is widely found throughout the Brazilian territory, with the exception of some regions of the north‐eastern semi‐arid region, due to the scarcity of water (Jardim et al, 2003), since it has a semiaquatic habit and needs water to perform vital functions such as copulation (Lange & Schmidt, 2014; Pachaly & Gioso, 2001; Vieira et al, 2021). The capybara diet is strictly herbivorous and has shown population growth due to greater availability of food and decline of large predators (Kihara et al, 2019).…”