Health evaluation, parasite diversity and reproductive profiling in the critically endangered painted terrapin (Batagur borneoensis, Schlegel and Muller, 1844)
Painted terrapin (Batagur borneoensis) are critically endangered, hard-shelled freshwater chelonians that inhabit rivers and estuaries of Malaysia, Brunei Darussalam, Thailand and Indonesia. The natural range of this terrapin species has reduced dramatically over the years due to pressures fro...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/85536/1/FPV%202019%207%20UPM%20ir.pdf |
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| Summary: | Painted terrapin (Batagur borneoensis) are critically endangered, hard-shelled
freshwater chelonians that inhabit rivers and estuaries of Malaysia, Brunei Darussalam,
Thailand and Indonesia. The natural range of this terrapin species has reduced
dramatically over the years due to pressures from environmental disturbances, habitat
loss, and poaching. One of the ways to increase this species population is through captive
breeding. However, there have been no successful ex situ captive breeding programmes
of this species in South East Asia and this could be due to several factors like physical
health, hormones, environment and nutrition. The causative factors could not be
determined without conducting comparative health evaluation and reproductive
profiling between captive and wild painted terrapins. Therefore the present study was
conducted to evaluate the health and reproductive profile of wild B. borneoensis from
Sungai Linggi, Melaka, and a captive population from a zoological facility in Melaka,
Peninsular Malaysia. Blood was collected from 142 wild (50 adult male, 66 adult female,
7 sub-adult male, 11 sub-adult female, and 8 juveniles) and 12 adult (3 male and 9
female) captive painted terrapins for haematology and clinical biochemistry analyses,
and monthly reproductive hormone (progesterone, oestrogen and testosterone) profiling
through enzyme immunoassays (ELISA). All wild and captive painted terrapins were
also subjected to morphometry, physical examination and health screening which
included parasite detection and radiography. Changes in breeding colouration was
monitored and scored for the males. Normal ranges for haematology and plasma
biochemistry was established for the first time for wild B. borneoensis. Results indicated
that the captive terrapins are in poorer health condition based on physical abnormalities,
haematology, clinical biochemistry, and parasite burden compared to their wild
conspecifics. This could be due to several factors such as stress of captivity, improper
enclosure and poor nutrition. The most common lesions for the wild terrapins occurred
on the carapace region (65.5%), while that of the captive individuals were found on the
limbs (100.0%). The parasites that were encountered in this species include Falcaustra
(9.4%), Orientodiscus (1.9%), Ozobranchus (30.7%), and haemogregarines (45.3%),
which constitutes the first report for B. borneoensis. Helminth ova burden was more prevalent in the captive (66.7%) compared to the wild (50%) terrapins. Six wild females
were found to be gravid, while only one male and one female captive terrapin showed
indications of a normal breeding cycle. In the wild population, hormone profiles indicate
that mating and spermiation occurs in October-November before ovulation in December-
January. The breeding coloration of the wild male terrapins corresponded well with the
temporal cycle of reproductive hormones. In the captive population, mating and
ovulation occurs in October-November before spermiation in December-January, which
explains why the eggs produced by the captive females are not fertilised. The wild
population provided a baseline on the natural reproductive cycle of this species and
through this study, there was asynchrony of timing between spermiation in the captive
males and ovulation in the females. The reason for this hormonal imbalance could be
related to suboptimal health and husbandry in captivity. It is envisaged that the data
obtained will assist in the protection and conservation of this terrapin species in the wild
and also assist in the management of captive individuals meant for conservation breeding
in zoological facilities. |
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