Microbial contamination of artificially incubated Greater Rhea (Rhea americana) eggs

1. This paper is a report of biological agents that contaminate Greater Rhea (Rhea americana) eggs during artificial incubation. 2. The cleanliness of eggs when collected, and the period of storage prior to incubation, were investigated to assess their effects on microbial contamination and hatchability. 3. A total of 14 bacteria and 4 fungi species were isolated within the egg in the laboratory. 4. Microbial contamination was higher (24%) in very dirty eggs than in eggs which were clean or dirty (16%). Hatching success was lower (30%) for very dirty eggs, compared with 42% for clean or dirty eggs. 5. The percentage of microbial contamination of stored eggs (10%) did not differ significantly from that of non-stored ones (5%). 6. The extreme lower and upper limits of infection rate estimated for artificially incubated Greater Rhea eggs were 4% and 40%, respectively, being higher than in poultry species. 7. It is concluded that collecting eggs soon after laying will reduce the risk of microbial contamination.     

Physical characteristics and chemical composition of Greater Rhea (Rhea americana) eggs from wild and captive populations.

1. Eggs from wild and captive populations of Greater Rhea (Rhea americana) were studied to determine their physical and chemical characteristics. 2. Significant differences were found among populations in almost all chemical parameters studied, whereas within physical parameters only shell weight (as a proportion of the entire egg) and density showed differences. 3. Eggs from wild populations had the highest protein and linolenic acid and the lowest total lipid contents, while cholesterol levels of these eggs and of those from the largest captive area were the lowest.     

Ontogenetic Scaling of the Hindlimb Muscles of the Greater Rhea (Rhea americana)

The greater rhea (Rhea americana) is the largest South American bird. It is a cursorial, flightless species with long powerful legs and reduced forelimbs. The goal of this study was to explore how hindlimb muscles scale with body mass during postnatal growth and to analyze whether the specialized locomotion of this species affects the growth of muscle masses. The mass of 19 muscles and body mass were weighed in 21 specimens ranging from 1‐month‐old individuals to adults. Seventeen muscles scaled with positive allometry with respect to body mass, whereas two muscles scaled isometrically . The predominance of positive allometric growth in hindlimb muscles results in a limb with massive and powerful muscles specialized to support a large body mass and to attain relatively high running speeds. Analysis of muscle mass scaling is a simple and useful way to compare possible differences between locomotor styles, and it is valuable in studies that reconstruct the paleobiology of extinct taxa.     

Effect of age and body weight of Greater Rhea (Rhea americana) females on egg number, size and composition

1. A study was conducted to evaluate how body weight and age of each female are related to the number and physical and chemical characteristics of the eggs produced throughout a breeding season in a captive-bred population of Greater Rheas (Rhea americana). 2. Reproductive performance of 15 females of three age classes (5 individuals per class) was monitored; female body weight was recorded before laying-onset. All the eggs laid were collected and identified, and different morphometric variables, percentage of components and fatty acid composition were determined. 3. The earlier the female started egg-laying, the longer the laying period and the greater the overall number of eggs produced. The onset of egg-laying in turn seemed to be related to the attainment of a high body weight. 4. Except for length, the values of the morphometric variables of the egg and unsaturated fatty acids (palmitoleic, oleic and linoleic) increased with female age. 5. High body weight was associated with low palmitic and palmitoleic fatty acids and high linoleic, linolenic and total unsaturated fatty acids. 6. Live weight and age of females can determine several physical and chemical characteristics of eggs.     

Effects of storage conditions on hatchability of chicken eggs in a warm climate

1. A total of 3792 eggs from AF Bosbek layer parents were used to determine the effect of storage time on the hatchability of eggs kept either small end up (SEU) or small end down (SED).

2. These eggs were stored at room temperature (27°C‐31°C) or in an air‐conditioned room (20°C‐23°C), for two, three, six or seven days and incubated in four replicate hatches.

3. Eggs kept SEU improved hatchability even for short‐term storage when temperatures were high.

4. Simple air‐conditioning can reduce the temperature sufficiently for the viability of the embryo to be preserved for up to a week.     

Pulmonary aspergillosis in a great rhea (Rhea americana)

A 5-mo-old great rhea (Rhea americana) gradually became emaciated over a 1-wk period and died. Necropsy revealed several small yellow nodules in the lungs. Microscopically, the nodules consisted of granulomas containing numerous thin, 4-microm-diameter, septate, branching fungal hyphae. Aspergillus fumigatus grew readily on Sabouraud dextrose agar. This report appears to be the first of mycotic pneumonia in great rheas.     

Hindlimb bone maturation during postnatal life in the Greater Rhea (Rhea americana,Aves, Palaeognathae): Implications for palaeobiological and zooarchaeological interpretations

The objective of this study was to study the morphological pattern of bone maturation of the hindlimb bones of Rhea americana and find out how it can affect bone morphology after a taphonomic process. Juvenile specimens (n = 10) ranging from one month old to eight months old were studied. For comparison, bones from adults and juveniles from museum specimens (n = 4 and n = 6, respectively) were studied. In fresh bones, ossification centres were identified in the proximal and distal epiphyses of the tibiotarsi and in the proximal epiphysis of the tarsometatarsi, whereas the distal region of the femora and tarsometatarsi showed abundance of cartilage. The development and extension of the ossification centres of the tibiotarsi were different. In the proximal epiphysis, the centre presented less development with respect to the distal epiphysis. In the dry tibiotarsi, the proximal centre was absent and the distal one was well preserved. Both the fresh and dry juvenile tarsometatarsi presented unfused metatarsals and bulkier and wider aspect than the adult ones. The dry femora presented a noticeable excavation between condyles, whereas the dry tarsometatarsi showed the absence of the proximal epiphysis. The femora, tibiotarsi and tarsometatarsi possessed different traits of immaturity, which differentially affect the morphology of the preserved bones during a taphonomic process.     

Morphometry of the heart of greater rhea (Rhea americana americana,Linnaeus, 1758)

Heart diseases in birds are frequent and generate significant production disorders. Morphometry is a valuable tool to provide fundamental information about heart conditions. Few studies have addressed morphological aspects of the heart of ratite birds, such as the Greater rhea. The present study aimed to analyse rhea heart morphometry, comparing young and adult subjects, in order to provide relevant information for the diagnosis of heart disease in this species. Hearts of young (n = 10) and adult (n = 10) female rheas were used in this research. Heart length and width and sternum length were measured using a caliper. Heart length and width and sternum length in adults were approximately three times greater than in young individuals. The left ventricular wall (LVW) was thicker than the right ventricular wall (RVW) at all ages, and the RVW was thicker in adults when compared to young subjects. The basal and middle RVW regions thicken with advancing age, and the thickness of the interventricular septum (ISW) occupies an intermediate position between the LVW and RVW. In general, an increase in rhea heart thickness and size relative to age is observed. The morphometric variations between young and adult rhea hearts observed in the present study may serve as a comparative subsidy for the diagnosis of cardiac abnormalities observed in this species.     

Coefficients for the estimation of fresh weight and volume of Greater Rhea eggs

1. Specific values of constants needed to estimate fresh weight (Kw) and volume (Kv) of Greater Rhea eggs were obtained. 2. The average value for the weight coefficient (Kw) was 0.57, whereas that for volume (Kv) was 0.51. Accuracy of results obtained with these values was +/-2.1% and +/-3.5%, respectively. 3. The fresh weight and volume of Greater Rhea eggs can be easily estimated by means of these specific coefficients when those measurements cannot be taken directly.     

Outbreak of Philophthalmus gralli in four greater rheas (Rhea americana)

Using slit‐lamp biomicroscopy, conjunctival biopsy, and morphological identification, a flock of four Greater rheas (Rhea americana) in Arizona were diagnosed with conjunctivitis secondary to Philophthalmus gralli (P. gralli) infection. Aquatic snails from the exhibit’s water source were identified as Melanoides tuberculatus, a known vector for P. gralli. Comparison of partial sequences of DNA regions from P. gralli adults removed from the rheas and metacercariae from the aquatic snails demonstrated a 100% match, confirming the source of infection. The flock was divided into two treatment groups: the most severely affected rheas received both manual removal of trematodes and praziquantel 1% ointment OU q12 h and the least severely affected rheas were only given praziquantel 1% ointment OU q12 h. The rheas were permanently relocated away from the infected water source and aquatic snails. Initial resolution was seen at 17 weeks in the most severely affected rhea, which had 675 adult P. gralli removed and topical praziquantel. The two rheas that only received topical praziquantel showed resolution within 3 and 15 weeks. Current recommendations for treating P. gralli include: manual removal of trematodes, topical praziquantel 1% ointment, and relocation away from infected water sources and aquatic snails.     

The length of storage of emu eggs and resultant effects on hatchability

Emu (Dromaius novaehollandiae) are a large flightless bird and are members of the Ratite family. Emu originated from Australia and have long been raised for their meat and oil. The cost associated with raising emu is high, which makes emu meat and products expensive. Emu have very low hatchability rates when compared with other commercial poultry. To date, little research has been published on egg storage conditions of emu eggs, which may contribute to the decreased hatchability of the eggs. In this study, eggs were stored for times ranging from 1 to 8 wk and subsequent effects on moisture loss and hatchability was recorded. We found significant differences (P < 0.0104) in hatchability of emu eggs due to storage time. Significant differences (P < 0.0001) were also found in moisture loss due to egg storage. Based on these data, 2 wk of egg storage appears to be the optimal storage time. After 3 wk of storage, hatchability begins to decrease.     

Chronic fascioliasis in farmed and wild greater rheas (Rhea americana)

From 50 farmed Rhea americana slaughtered for human consumption, adult forms and eggs of Fasciola hepatica were found in 4. The other three livers were free of flukes but did show lesions caused by larval fluke migration. Histological lesions were similar to those caused by flukes in cattle and sheep. The rheas were from an endemic area of ruminant fascioliasis in Southern Brazil. F. hepatica eggs were also found in faecal samples of wild rheas from another endemic area in Southern Brazil. It is likely that the rheas play a role in the transmission of the disease to ruminants and could be jeopardizing the control of this parasitosis in endemic areas. From the best of our knowledge this is the first report of fascioliasis in R. americana.     

Observations on helminth infections of free-living and captive rheas (Rhea americana) in Brazil

The present work describes helminth infection of eight free-living and 12 captive rheas (Rhea americana) from, respectively, Pantanal of Mato Grosso do Sul State, and Jaboticabal, Sao Paulo State, Brazil. Captive birds were young and had a high mortality rate, while free-living birds were adult and apparently healthy. Infections were evaluated by post-mortem examination of internal organs and recovery of helminths using standard parasitological procedures. Seven species of nematodes (Sicarius uncinipenis, Torquatoides crotophaga, Deletrocephalus dimidiatus, D. cesarpintoi, Paradeletrocephalus minor, Capillaria venteli and Dicheilonema rheae) and two species of cestodes (Houttuynia struthionis and Chapmania tauricolis) were identified. P. minor, which inhabits the large intestine, was the most common helminth in free-living birds (63.9%). In captive rheas, a mean parasitic load of 173 helminths per host was found. The gizzard of these birds was the most parasitized organ and S. uncinipenis was most common (92.5%). Parasitism of free-living and captive birds and associated pathology are discussed.     

Parasites from farmed ostriches (Struthio camelus) and rheas (Rhea americana) in Europe

During a 4-year-period, more than 500 ostriches and several rheas, all born in European countries and raised in Spain and Portugal, have been analyzed for the presence of ectoparasites and endoparasites. A total of 29 parasite species have been found, most of them of the gastrointestinal tract. Some of the helminth species found may represent spureous parasitosis, as only the eggs (of an ascarid and a trematode) were found in some samples. From the organisms identified, the ectoparasites (lice-Struthiolipeurus rheae, S. nandu; mites-Dermoglyphus pachycnemis, Gabucinia bicaudata), helminths (cestoda-Houttuynia struthionis- and nematoda-Libyostrongylus sp., Codiostomum struthionis-) and the ciliate Balantidium struthionis are known as ratite specific parasites. Capillaria eggs and larvae were also found; there are no previous records of this parasite from ostriches, and the data available do not allow to do a temptative specific diagnosis. Among protozoa, most of the species now found are described for the first time in ratites. They include organisms also found in other birds (Trichomonas gallinae, Tetratrichomonas gallinarum, Chilomastix gallinarum, Spironucleus meleagridis and Pleuromonas jaculans), and organisms whose specific status cannot be established until further analysis are performed (Cryptosporidium sp., Eimeria sp. and/or Isospora sp., Entamoeba sp. of the one-nucleate and of the eight-nucleate mature cyst groups, Endolimax sp., Iodamoeba sp., Monocercomonas sp., Retortamonas sp., Giardia sp., Blastocystis sp. and euglenids).     

Efficiency of the cloacal sexing technique in greater rhea chicks (Rhea americana)

1. The feasibility and accuracy of the cloacal sexing technique in greater rhea chicks was assessed using chicks of two captive populations of greater rhea in Córdoba, Argentina.

2. A total of 46 greater rhea chicks of 2 to 3 months of age were randomly arranged into three groups and the members of each group were sexed by a different operator.

3. A feather of each chick was plucked for sexing through a molecular method and results were used as controls.

4. Sex was correctly assigned by cloacal inspection in 98% of the cases. Chick manipulation was easily performed and no infections or traumatic lesions were observed a posteriori.

5. Cloacal sexing of rhea chicks up to 3 months of age does not affect animal welfare and should be considered an efficient alternative to molecular methods.     

Evaluation of the health of free-ranging greater rheas (Rhea americana) in Argentina

The health of 22 free-ranging adult rheas (Rhea americana) examined and sampled during a translocation/reintroduction project and six juvenile rheas kept in semicaptivity was investigated, and details of their haematology and plasma biochemistry are presented. Serological testing for antibodies to infectious agents was negative for infectious laryngotracheitis, avian adenovirus, avian influenza, avian reovirus, infectious bursal disease, infectious bronchitis virus, paramyxovirus types 1, 2, and 3, fowlpox and Salmonella Pullorum. Antibodies to Chlamydophila species were found in 25 of 27 of the birds, and 22 of 25 had antibodies to Aspergillus species. Ova of gastrointestinal nematodes of the genus Capillaria were identified, and the anoplocephalid cestode Monoecocestus cf rheiphilus was identified in R americana for the first time.     

Effects of some egg characteristics on the mass loss and hatchability of ostrich (Struthio camelus) eggs

1. This study was conducted to examine some egg characteristics and determine the effects of eggshell thickness and eggshell porosity on water loss and hatchability of eggs in ostriches. 2. Shell thickness did not correlate significantly with hatchability. However, eggs of low shell thickness lost more mass (13.03%) than those with intermediate (11.22%) and high (10.36%) shell thickness. Mass loss during incubation was higher in hatched (11.98%) than unhatched eggs (11.09%). Shell thickness was negatively correlated to egg mass loss (r = -0.65). 3. The pore density was correlated with hatchability. Hatchability was 50% lower in eggs with low pore densities (40.93%) than with high densities (80.94%). Pore density was positively correlated with egg mass loss (r = 0.63). Incubation mass losses of hatched and unhatched eggs were not significantly different. 4. Mean eggshell water vapour conductance (G) value and shell conductance constant (k) were 87.77 +/- 4.21 mg H2O/d/Torr and 2.44 respectively (n = 15). 5. Because of eggshell functional properties and resulting low egg mass loss hatchability is low when ostrich eggs are artificially incubated. The mass of eggs used in the experiment was relatively high and their eggshell water vapour conductance was low. As a result, egg incubation mass loss was lower than it should be. It is concluded that incubator humidity should be low (25%) to allow enough mass loss during incubation from the eggs.