Currently the only captive population of beira antelope (Dorcatragus megalotis) is held at the Al... more Currently the only captive population of beira antelope (Dorcatragus megalotis) is held at the Al Wabra Wildlife Preservation, Qatar. An outbreak of a severe respiratory disease--fibrinous pleuropneumonia syndrome, most likely caused by Mycoplasma ovipneumoniae--led to a marked population decline. Reactive systemic inflammatory (AA) amyloidosis was noted as a chronic manifestation of the disease. Blood samples had been collected for biochemistry and hematology baseline values prior to the outbreak. Population-level changes were analyzed before and during the course of the outbreak in selected blood parameters (white blood cells [WBC], blood urea nitrogen [BUN], and creatinine). The annual population WBC increased and decreased concurrently with the population size, with a significant correlation between the two measures (R = 0.92; P = 0.001). Both BUN and creatinine values were higher during the outbreak. These values peaked at the same time as mortality, which was 1 yr after the WBC peak. These changes were interpreted as the transition from an acute disease with a primary respiratory manifestation into a chronic condition where renal amyloidosis led to chronic renal failure and death. Also, elevated liver values in diseased animals were attributed to amyloidosis. Parallels to a literature report on a lung disease complex caused by M. ovipneumoniae in bighorn sheep (Ovis canadensis) were found. Trends in population-level blood values of the beira antelopes implicate amyloidosis as a significant, long-term consequence of the putative Mycoplasma infection.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2014
Basal metabolic rates in mammals are mainly determined by body mass, but also by ecological facto... more Basal metabolic rates in mammals are mainly determined by body mass, but also by ecological factors. Some mammalian species inhabiting hot, dry environments were found to have lower metabolic rates compared to temperate species. We studied energy metabolism in Phillip's dikdik (Madoqua saltiana phillipsi), a small antelope inhabiting xeric shrubland habitats in the Eastern 'horn' of Africa, and compared results to literature data. We measured body mass (BM) changes and digestibility in 12 adults kept on different food intake levels to determine, by extrapolation to zero BM change, maintenance energy requirements (MEm) for metabolizable energy (ME). The MEm averaged at 404 ± 20 kJ ME kg BM −0.75 d −1 . In addition we conducted 24 h-chamber respirometry with seven fed (non-fasted) individuals. Their mean metabolic rate as calculated from oxygen consumption was 403 ± 51 kJ kg BM −0.75 d −1 , corroborating the results of the feeding experiments. Selecting the 20 lowest values of the respiration measurement period to estimate resting metabolic rate (RMR) resulted in a mean RMR of 244 ± 39 kJ kg BM −0.75 d −1 , which was not significantly lower than the expected basal metabolic rate of 293 kJ kg BM −0.75 d −1 . Therefore, resting metabolism was similar to the expected average basal metabolism of a mammal of this size, which suggests a comparatively low metabolic rate in dikdiks. Compared to literature data Phillip's dikdiks have a MEm similar to measurements reported for small domestic ruminants, but considerably lower than those reported for other wild ruminant species inhabiting temperate and cold climates.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2012
Ostriches (Struthio camelus) achieve digesta retention times, digesta particle size reduction and... more Ostriches (Struthio camelus) achieve digesta retention times, digesta particle size reduction and digestibilities equal to similar-sized herbivorous mammals, in contrast to some other avian herbivores. The sequence of digestive processes in their gastrointestinal tract, however, is still unexplored. Using two groups of four ostriches (mean body mass 75.1± 17.3 kg) kept on fresh alfalfa, we tested the effect of two intake levels (17 and 42 g dry matter kg − 0.75 d − 1 ) on the mean retention time (MRT) of a solute and three different-sized (2, 10, 20 mm) particle markers, mean faecal particle size (MPS), and digestibility. Intake level did not affect MRT, but MPS (0.74 vs. 1.52 mm) and dry matter digestibility (81 vs. 78%). The solute marker (MRT 22-26 h) was excreted faster than the particle markers; there was no difference in the MRT of 10 and 20 mm particles (MRT 28-32 h), but 2 mm particles were retained longer (MRT 39-40 h). Because the solute marker was not selectively retained, and wet-sieving of gut contents of slaughtered animals did not indicate smaller particles in the caeca, the long MRT of small particles is interpreted as intermittent excretion from the gizzard, potentially due to entrapment in small grit. The marker excretion pattern also showed intermittent peaks for all markers in five of the animals, which indicates non-continuous outflow from the gizzard. When adding our data to literature data on avian herbivores, a dichotomy is evident, with ostrich and hoatzin (Opisthocomus hoazin) displaying long MRTs, high digestibilities, and gut capacities similar to mammalian herbivores, and other avian herbivores such as grouse, geese or emus with shorter MRTs, lower fibre digestibilities and lower gut capacities. In the available data for all avian herbivores where food intake and MRTs were measured, this dichotomy and food intake level, but not body mass, was related to MRT, adding to the evidence that body mass itself may not be sole major determinant of digestive physiology. The most striking difference between mammalian and avian herbivores from the literature is the fundamentally lower methane production measured in the very few studies in birds including ostriches, which appears to be at the level of reptiles, in spite of general food intake levels of a magnitude as in mammals. Further studies in ostriches and other avian herbivores are required to understand the differences in digestive mechanisms between avian and mammalian herbivores.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2015
Digesta flow plays an important role in ruminant digestive physiology. We measured the mean reten... more Digesta flow plays an important role in ruminant digestive physiology. We measured the mean retention time (MRT) of a solute and a particle marker in the gastrointestinal tract (GIT) and the reticulorumen (RR) of five gazelles and one dikdik species. Species-specific differences were independent from body mass (BM) or food intake. Comparative evaluations (including up to 31 other ruminant species) indicate that MRT GIT relate positively to BM, and are less related to feeding type (the percentage of grass in the natural diet, %grass) than MRT RR. The MRT particle RR is related to BM and (as a trend) %grass, matching a higher RR capacity with increasing BM in grazers compared to browsers. MRT solute RR is neither linked to BM nor to %grass but shows a consistent phylogenetic signal. Selectivity factors (SF; MRT particle /MRT solute , proxies for the degree of digesta washing) are positively related to %grass, with a threshold effect, where species with N 20% grass have higher SF. These findings suggest that in different ruminant taxa, morphophysiological adaptations controlling MRT solute RR evolved to achieve a similar SF RR in relation to a %grass threshold. A high SF could facilitate an increased microbial yield from the forestomach. Reasons for variation in SF above the %grass threshold might represent important drivers of ruminant diversification and await closer investigation.
The Spix&... more The Spix's macaw (Cyanopsitta spixii) is considered the world's most endangered parrot, with the last wild bird disappearing in 2001 and only 74 birds in captivity. To establish hematologic and plasma biochemical reference ranges and to look for differences relative to sex, age, and season, we obtained blood samples from 46 captive Spix's macaws (23 male, 23 female) housed in aviaries at the Al Wabra Wildlife Preservation in the State of Qatar. No significant differences in hematologic or plasma biochemical values were found between females and males. Adult and juvenile birds differed in mean concentrations of glucose, total protein, amylase, cholesterol, and phosphorus; in percentages of heterophils and lymphocytes; and in the absolute lymphocyte count. Total protein, cholesterol, and phosphorus concentrations; hematocrit; and heterophil and lymphocyte counts differed significantly by season. Baseline hematologic and plasma biochemical ranges were established, which may be useful as reference values for clinicians working with this highly endangered species.
Currently the only captive population of beira antelope (Dorcatragus megalotis) is held at the Al... more Currently the only captive population of beira antelope (Dorcatragus megalotis) is held at the Al Wabra Wildlife Preservation, Qatar. An outbreak of a severe respiratory disease--fibrinous pleuropneumonia syndrome, most likely caused by Mycoplasma ovipneumoniae--led to a marked population decline. Reactive systemic inflammatory (AA) amyloidosis was noted as a chronic manifestation of the disease. Blood samples had been collected for biochemistry and hematology baseline values prior to the outbreak. Population-level changes were analyzed before and during the course of the outbreak in selected blood parameters (white blood cells [WBC], blood urea nitrogen [BUN], and creatinine). The annual population WBC increased and decreased concurrently with the population size, with a significant correlation between the two measures (R = 0.92; P = 0.001). Both BUN and creatinine values were higher during the outbreak. These values peaked at the same time as mortality, which was 1 yr after the WBC peak. These changes were interpreted as the transition from an acute disease with a primary respiratory manifestation into a chronic condition where renal amyloidosis led to chronic renal failure and death. Also, elevated liver values in diseased animals were attributed to amyloidosis. Parallels to a literature report on a lung disease complex caused by M. ovipneumoniae in bighorn sheep (Ovis canadensis) were found. Trends in population-level blood values of the beira antelopes implicate amyloidosis as a significant, long-term consequence of the putative Mycoplasma infection.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2014
Basal metabolic rates in mammals are mainly determined by body mass, but also by ecological facto... more Basal metabolic rates in mammals are mainly determined by body mass, but also by ecological factors. Some mammalian species inhabiting hot, dry environments were found to have lower metabolic rates compared to temperate species. We studied energy metabolism in Phillip's dikdik (Madoqua saltiana phillipsi), a small antelope inhabiting xeric shrubland habitats in the Eastern 'horn' of Africa, and compared results to literature data. We measured body mass (BM) changes and digestibility in 12 adults kept on different food intake levels to determine, by extrapolation to zero BM change, maintenance energy requirements (MEm) for metabolizable energy (ME). The MEm averaged at 404 ± 20 kJ ME kg BM −0.75 d −1 . In addition we conducted 24 h-chamber respirometry with seven fed (non-fasted) individuals. Their mean metabolic rate as calculated from oxygen consumption was 403 ± 51 kJ kg BM −0.75 d −1 , corroborating the results of the feeding experiments. Selecting the 20 lowest values of the respiration measurement period to estimate resting metabolic rate (RMR) resulted in a mean RMR of 244 ± 39 kJ kg BM −0.75 d −1 , which was not significantly lower than the expected basal metabolic rate of 293 kJ kg BM −0.75 d −1 . Therefore, resting metabolism was similar to the expected average basal metabolism of a mammal of this size, which suggests a comparatively low metabolic rate in dikdiks. Compared to literature data Phillip's dikdiks have a MEm similar to measurements reported for small domestic ruminants, but considerably lower than those reported for other wild ruminant species inhabiting temperate and cold climates.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2012
Ostriches (Struthio camelus) achieve digesta retention times, digesta particle size reduction and... more Ostriches (Struthio camelus) achieve digesta retention times, digesta particle size reduction and digestibilities equal to similar-sized herbivorous mammals, in contrast to some other avian herbivores. The sequence of digestive processes in their gastrointestinal tract, however, is still unexplored. Using two groups of four ostriches (mean body mass 75.1± 17.3 kg) kept on fresh alfalfa, we tested the effect of two intake levels (17 and 42 g dry matter kg − 0.75 d − 1 ) on the mean retention time (MRT) of a solute and three different-sized (2, 10, 20 mm) particle markers, mean faecal particle size (MPS), and digestibility. Intake level did not affect MRT, but MPS (0.74 vs. 1.52 mm) and dry matter digestibility (81 vs. 78%). The solute marker (MRT 22-26 h) was excreted faster than the particle markers; there was no difference in the MRT of 10 and 20 mm particles (MRT 28-32 h), but 2 mm particles were retained longer (MRT 39-40 h). Because the solute marker was not selectively retained, and wet-sieving of gut contents of slaughtered animals did not indicate smaller particles in the caeca, the long MRT of small particles is interpreted as intermittent excretion from the gizzard, potentially due to entrapment in small grit. The marker excretion pattern also showed intermittent peaks for all markers in five of the animals, which indicates non-continuous outflow from the gizzard. When adding our data to literature data on avian herbivores, a dichotomy is evident, with ostrich and hoatzin (Opisthocomus hoazin) displaying long MRTs, high digestibilities, and gut capacities similar to mammalian herbivores, and other avian herbivores such as grouse, geese or emus with shorter MRTs, lower fibre digestibilities and lower gut capacities. In the available data for all avian herbivores where food intake and MRTs were measured, this dichotomy and food intake level, but not body mass, was related to MRT, adding to the evidence that body mass itself may not be sole major determinant of digestive physiology. The most striking difference between mammalian and avian herbivores from the literature is the fundamentally lower methane production measured in the very few studies in birds including ostriches, which appears to be at the level of reptiles, in spite of general food intake levels of a magnitude as in mammals. Further studies in ostriches and other avian herbivores are required to understand the differences in digestive mechanisms between avian and mammalian herbivores.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2015
Digesta flow plays an important role in ruminant digestive physiology. We measured the mean reten... more Digesta flow plays an important role in ruminant digestive physiology. We measured the mean retention time (MRT) of a solute and a particle marker in the gastrointestinal tract (GIT) and the reticulorumen (RR) of five gazelles and one dikdik species. Species-specific differences were independent from body mass (BM) or food intake. Comparative evaluations (including up to 31 other ruminant species) indicate that MRT GIT relate positively to BM, and are less related to feeding type (the percentage of grass in the natural diet, %grass) than MRT RR. The MRT particle RR is related to BM and (as a trend) %grass, matching a higher RR capacity with increasing BM in grazers compared to browsers. MRT solute RR is neither linked to BM nor to %grass but shows a consistent phylogenetic signal. Selectivity factors (SF; MRT particle /MRT solute , proxies for the degree of digesta washing) are positively related to %grass, with a threshold effect, where species with N 20% grass have higher SF. These findings suggest that in different ruminant taxa, morphophysiological adaptations controlling MRT solute RR evolved to achieve a similar SF RR in relation to a %grass threshold. A high SF could facilitate an increased microbial yield from the forestomach. Reasons for variation in SF above the %grass threshold might represent important drivers of ruminant diversification and await closer investigation.
The Spix&... more The Spix's macaw (Cyanopsitta spixii) is considered the world's most endangered parrot, with the last wild bird disappearing in 2001 and only 74 birds in captivity. To establish hematologic and plasma biochemical reference ranges and to look for differences relative to sex, age, and season, we obtained blood samples from 46 captive Spix's macaws (23 male, 23 female) housed in aviaries at the Al Wabra Wildlife Preservation in the State of Qatar. No significant differences in hematologic or plasma biochemical values were found between females and males. Adult and juvenile birds differed in mean concentrations of glucose, total protein, amylase, cholesterol, and phosphorus; in percentages of heterophils and lymphocytes; and in the absolute lymphocyte count. Total protein, cholesterol, and phosphorus concentrations; hematocrit; and heterophil and lymphocyte counts differed significantly by season. Baseline hematologic and plasma biochemical ranges were established, which may be useful as reference values for clinicians working with this highly endangered species.
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