Hematology, plasma biochemistry, and trace element reference values for free-ranging adult Magellanic Penguins (Spheniscus magellanicus)

Minimum anesthetic concentration of isoflurane and sevoflurane and cardiorespiratory effects of varying inspired oxygen fractions in Magellanic penguins (Spheniscus magellanicus)

The aim of this study was to determine the minimum anesthetic concentration of isoflurane (MACISO) and sevoflurane (MACSEVO) and evaluate the cardiorespiratory changes induced by varying fractions of inspired oxygen (FiO2) in Magellanic penguins (Spheniscus magellanicus). Twenty adult penguins (3.53 ± 0.44 kg) of undetermined sex were used. Both MACISO (n = 9) and MACSEVO (n = 13) were established using an up-and-down design. Next, twelve mechanically ventilated penguins were maintained at 1 MACISO or 1 MACSEVO (n = 6 per group) with the FiO2 initially set at 1.0. Three FiO2 values (0.6, 0.4 and 0.2) were then held constant during anesthesia for 20 minutes each. Arterial blood samples were collected for gas analysis after the 20-minute period for each FiO2. Mean ± SD MACISO was 1.93 ± 0.10% and MACSEVO was 3.53 ± 0.13%. Other than heart rate at 0.6 FiO2 (86 ± 11 beats/minute in MACISO and 132 ± 37 beats/minute in MACSEVO; p = 0.041), no significant cardiorespiratory differences were detected between groups. In both groups, decreasing the FiO2 produced increased pH values and reduced partial pressures of carbon dioxide and bicarbonate. Partial pressures of oxygen (PaO2) gradually lowered from 1.0 FiO2 through 0.2 FiO2, though hypoxemia (PaO2 < 80 mmHg) occurred only with the latter FiO2. The MACISO and the MACSEVO for the Magellanic penguin fell within the upper range of reported avian MAC estimates. To prevent hypoxemia in healthy, mechanically ventilated, either isoflurane- or sevoflurane-anesthetized Magellanic penguins, a minimum FiO2 of 0.4 should be used.

Clinical Chemistry and Haematology Values of a Captive Population of Humboldt Penguins (Spheniscus humboldti)

Reference intervals for clinical chemistry and haematology analytes are essential for the interpretation of blood results, but limited data are available for Humboldt penguins (Spheniscus humboldti) in zoological collections as well as in the wild. The aim of the present study was therefore to establish reference intervals for a series of clinical chemistry and haematology analytes in a single zoological population of Humboldt penguins. Furthermore, possible variations of the analytes influenced by the age and sex of the individuals were investigated. Lithium heparinized plasma and whole blood samples from 39 animals were analysed and statistically evaluated. The following clinical chemistry analytes were significantly higher in females: glutamate dehydrogenase (p = 0.0003), alanine transaminase (p = 0.0005), alkaline phosphatase (p = 0.0245), aspartate aminotransferase (p = 0.0043), creatine kinase (p = 0.0016), lactate dehydrogenase (p < 0.0001), inorganic phosphorus (p = 0.0223), and sodium (p = 0.0415). No significant differences between males and females were found for any haematology analyte. Cholesterol (p = 0.0233; -0.39), white blood cell count (p = 0.0208; -0.40), and absolute heterophiles (p = 0.0148; -0.42) had significant negative correlations with the age of the penguins. The results indicate that the factors of sex and age should be considered when interpreting the results of haematological and clinical biochemistry assays, and further studies are needed to determine whether there are more differences in other age groups or seasons.

Evaluation of the Effects of Administering Ultradiluted Avena sativa and Echinacea angustifolia on the Hematological Parameters of Magellanic penguins (Spheniscus magellanicus) during the Reproductive Period

BACKGROUND AND AIMS

Penguins are seabirds that manifest physiological and immunological alterations during the reproductive season. The objectives of this study were to evaluate the laboratory parameters of male and female Magellanic penguins and to determine the penguins' hematological response to homeopathic medicines during that reproductive period.

METHODS

Penguins (N = 18), kept under human care in a zoological park setting, were evaluated during the reproductive period and were divided randomly into two groups: a group subjected to treatment with Echinacea angustifolia 6cH and Avena sativa 6cH (N = 8; four breeding couples), and a placebo control group (N = 10; five breeding couples). The investigators were blinded to treatment allocation. Two-way ANOVA was performed to determine whether the experimental group (control or verum) and the sex of the animal had any significant effect on the variation of each hematological parameter between the samples. One-way ANOVA was performed on hematological parameters for which the sex did not present a significant effect. The significance level was p ≤0.05.

RESULTS

Significant effects were seen regarding the following: mean corpuscular volume (MCV), in which the verum group showed an increase (29.78 ± 52.95 fL) while the control group showed stability/reduction (-3.08 ± 46.36 fL) (p = 0.049); proportion of heterophils, in which the verum group showed a less marked increase (8.38 ± 12.53%) than that of the control group (18.00 ± 9.37%) (p = 0.010); lymphocyte concentration, in which the verum group showed less marked reduction (-4.39 ± 2.21 × 109 cells/L) than that of the control group (-1.56 ± 2.76 × 109 cells/L) (p = 0.001); and proportion of lymphocytes, in which the verum group showed a less marked reduction (-6.75 ± 10.35%) than that of the control group (-17.3 ± 8.73%) (p = 0.002).

CONCLUSION

Comparison of samples collected before and during the reproductive period showed that, regardless of group allocation, there were differences in the effects on MCV, heterophils and lymphocytes. Treatment with Echinacea angustifolia and Avena sativa resulted in maintenance of lymphocyte levels in Magellanic penguins during the breeding period, thus aiding these birds' immunity.

First assessment of debris pollution in the gastrointestinal content of juvenile Magellanic penguins (Spheniscus magellanicus) stranded on the west south Atlantic coasts

This paper provides the first evidence of debris pollution, including plastic, in juvenile Magellanic penguins (Spheniscus magellanicus) found stranded on the Atlantic coast of southern Buenos Aires Province, Argentina. Macro-, meso- and microparticles of anthropogenic origin were observed in 100 % of the studied birds, with debris abundance ranging between 33 and 200 items/bird. Microparticles represented 91 % of the total debris and 97 % of them were fibers. Black particles were the most abundant (30 %), followed by transparent (26 %), blue (14 %), yellow (10.3 %), and red (10 %). Infrared and Raman spectroscopy identified 62.7 % of the total particles as plastics, with polypropylene (27.8 %) and polyester (21.6 %) being the most abundant polymers. Semi-synthetic cellulosic fibers, metallic particles, and pigments were also found. The presence of metallic microparticles was suggested for the first time in penguins. Stranded juvenile Magellanic penguins are proposed as promising bioindicators of plastic pollution in the South Atlantic.

Importance of health assessments for conservation in noncaptive wildlife

Wildlife health assessments help identify populations at risk of starvation, disease, and decline from anthropogenic impacts on natural habitats. We conducted an overview of available health assessment studies in noncaptive vertebrates and devised a framework to strategically integrate health assessments in population monitoring. Using a systematic approach, we performed a thorough assessment of studies examining multiple health parameters of noncaptive vertebrate species from 1982 to 2020 (n = 261 studies). We quantified trends in study design and diagnostic methods across taxa with generalized linear models, bibliometric analyses, and visual representations of study location versus biodiversity hotspots. Only 35% of studies involved international or cross-border collaboration. Countries with both high and threatened biodiversity were greatly underrepresented. Species that were not listed as threatened on the International Union for Conservation of Nature Red List represented 49% of assessed species, a trend likely associated with the regional focus of most studies. We strongly suggest following wildlife health assessment protocols when planning a study and using statistically adequate sample sizes for studies establishing reference ranges. Across all taxa blood analysis (89%), body composition assessments (81%), physical examination (72%), and fecal analyses (24% of studies) were the most common methods. A conceptual framework to improve design and standardize wildlife health assessments includes guidelines on the experimental design, data acquisition and analysis, and species conservation planning and management implications. Integrating a physiological and ecological understanding of species resilience toward threatening processes will enable informed decision making regarding the conservation of threatened species.

HEMATOLOGIC METRICS FROM OLROG'S GULL (LARUS ATLANTICUS) DURING THE NONBREEDING SEASON IN ARGENTINA

Ecophysiology and conservation studies often require the prior establishment of baseline physiologic metrics. For instance, expected reference intervals for health metrics are valuable tools for veterinarians and conservationists who monitor the health status of endangered populations and species. This study establishes reference intervals for hematologic metrics in free-ranging Olrog's gull (Larus atlanticus) during the nonbreeding season. Fifty-six gulls (immature and adults) were captured and studied in Mar del Plata and neighboring coastal areas (Buenos Aires, Argentina) during the winter of 2018 (n = 22) and 2019 (n = 34). Hematocrit, red blood cells (erythrocytes), hemoglobin, mean cell volume, mean cell hemoglobin (MCH), MCH concentration, white blood cells (WBC; leukocytes), heterophils, lymphocytes, eosinophils, monocytes, and basophils were analyzed. Additionally, the variability of hematologic metrics according to body weight, sex, age, and calendar year was examined. Hematologic metrics were in line with those reported in other seabird species. Males had greater body weight and MCH than females. The heterophil to lymphocyte ratio and lymphocyte levels were higher in adults than in immatures. Hematocrit, WBC, heterophils, and basophils also varied significantly between calendar years. The results highlight the importance of appropriate metrics and reference intervals for monitoring the health status of this threatened species, and it is recommended to implement such comparative assessments among populations.

Seasonal variation in sex-specific immunity in wild birds

Whilst the immune system often varies seasonally and exhibits differences between males and females, the general patterns in seasonality and sex differences across taxa have remained controversial. Birds are excellent model organisms to assess these patterns, because the immune system of many species is well characterised. We conducted a meta-analysis using 41 wild bird species from 24 avian families to investigate sex differences and seasonal (breeding/non-breeding) variations in immune status, including white blood cell counts, phytohaemagglutinin (PHA) test, bacteria-killing ability (BKA), haemolysis and haemagglutination assays. We found male-biased macrophage concentration, BKA and haemolysis titers, but only during the breeding season. Sex-specific heterophil concentrations, heterophil/lymphocyte ratios and PHA responses differed between breeding and non-breeding, suggesting larger changes in males than in females. Importantly, sex differences in immune status are stronger during the breeding period than during the non-breeding period. Taken together, our study suggests that both seasonal variation and sex differences in immune system are common in birds, although their associations are more complex than previously thought.

Epidemiology, hematology, and unusual morphological characteristics of Plasmodium during an avian malaria outbreak in penguins in Brazil

Avian malaria is a mosquito-borne disease caused by Plasmodium spp. protozoa, and penguins are considered particularly susceptible to this disease, developing rapid outbreaks with potentially high mortality. We report on an outbreak of avian malaria in Magellanic penguins (Spheniscus magellanicus) at a rehabilitation center in Espírito Santo, southeast Brazil. In August and September 2015, a total of 89 Magellanic penguins (87 juveniles and 2 adults) received care at Institute of Research and Rehabilitation of Marine Animals. Over a period of 2 weeks, Plasmodium infections were identified in eight individuals (9.0%), four of which died (mortality = 4.5%, lethality = 50%). Blood smears and sequencing of the mitochondrial cytochrome b gene revealed the presence of Plasmodium lutzi SPMAG06, Plasmodium elongatum GRW06, Plasmodium sp. PHPAT01, Plasmodium sp. SPMAG10, and Plasmodium cathemerium (sequencing not successful). Two unusual morphological features were observed in individuals infected with lineage SPMAG06: (a) lack of clumping of pigment granules and (b) presence of circulating exoerythrocytic meronts. Hematological results (packed cell volume, plasma total solids, complete blood cell counts) of positive individuals showed differences from those of negative individuals depending on the lineages, but there was no overarching pattern consistently observed for all Plasmodium spp. The epidemiology of the outbreak and the phylogeography of the parasite lineages detected in this study support the notion that malarial infections in penguins undergoing rehabilitation in Brazil are the result of the spillover inoculation by plasmodia that circulate in the local avifauna, especially Passeriformes.