Social organization of the Asian elephant (Elephas maximus) in southern India inferred from microsatellite DNA

Social organization of the Asian elephant (Elephas maximus) is not well understood in the absence of long-term studies of identified individuals. Adult Asian elephant females and their young offspring of both sexes form matriarchal groups, with pubertal males dispersing from natal groups, but whether these social groups represent families and whether males show locational or social dispersal were unknown. Using nuclear microsatellite loci amplified from dung-extracted DNA of free-ranging elephants in a large southern Indian population, we demonstrate that female-led herds comprise closely related individuals that are indeed families, and that males exhibit non-random locational dispersal.     

Demography of captive Asian elephants (Elephas maximus) in southern India

Historically, the Asian elephant has never bred well in captivity. We have carried out demographic analyses of elephants captured in the wild or born in captivity and kept in forest timber camps in southern India during the past century. The average fecundity during this period was 0.095/adult female/year. During 1969–89, however, the fecundity was higher at 0.155/adult female/year, which compares favorably with wild populations. There was seasonality in births with a peak in January. The sex ratio of 129 male to 109 female calves at birth is not significantly different from equality, although the excess of male calves born mainly to mothers 20–40 years old may have biological significance. Mortality rates were higher in females than in males up to age 10, but much lower in females than in males above age 10 years. The population growth rate, based on the lower secundity over the century, was 0.5% per year, and based on the higher secundity during 1969–89, was 1.8% per year. The analyses thus showed that timber camp elephants in southern India could potentially maintain a stationary or increasing population without resorting to captures from the wild. Breeding efforts for elephants in zoos can thus profitably learn from the experience of traditional management systems in part of Asia. Zoo Biol 16:263–272, 1997. © 1997 Wiley-Liss, Inc.     

Sperm sex-sorting in the Asian elephant (Elephas maximus)

In captive Asian elephants, there is a strong need for production of female offspring to enhance reproduction, counter premature aging processes in female animals and reduce challenging management situations derived from husbandry of several bulls in one institution. Artificial insemination of flow cytometrically sex-sorted spermatozoa offers the possibility to predetermine the sex of offspring with high accuracy. The aims of this study were to determine a suitable semen extender and basic parameters for flow cytometrical sex-sorting of Asian elephant spermatozoa. In total 18 semen samples were collected by manual rectal stimulation from one bull. Sperm quality parameters and sex sortability of spermatozoa were evaluated after dilution in three semen extenders (MES-HEPES-skim milk, MES-HEPES, TRIS-citric acid) and DNA staining. MES-HEPES-skim milk was the only semen extender found suitable to sex Asian elephant spermatozoa. From 18 ejaculates collected, 12 were successfully sorted with a purity of 94.5+/-0.7% at an average sort rate of 1945.5+/-187.5 spermatozoa per second. Sperm integrity, progressive and total motility were 42.6+/-3.9%, 48.1+/-3.3%, 59.4+/-3.8% after DNA labelling, and 64.8+/-3.2%, 58.0+/-5.0%, 70.8+/-4.4% after sorting, respectively. After liquid storage of sorted spermatozoa for 12h at 4 degrees C, sperm integrity, progressive and total motility were 46.4+/-5.2%, 32.2+/-4.2% and 58.2+/-3.9%, respectively. The obtained results provide a promising base to inseminate Asian elephants with sexed semen.     

Estrogen metabolism in the Asian elephant (Elephas maximus)

Estradiol-17β metabolism was studied in two female Asian elephants (Elephas maximus). In an initial study, 500 μCi of tritiated estradiol-17β was injected iv into a single animal, and 0, 30 and 60 min serum samples were collected as well as all excreted urine and feces for 24 hr. In a second study, 1.5 mg unlabeled estradiol-17β was injected iv into a second animal and 0, 5, 15, 30, and 60 min serum samples and a 30 min urine sample were collected postinjection. Analyses of samples from both studies demonstrated a rapid conversion of free estradiol to conjugated forms in the serum. The first (5 min) serum sample following the injection of unlabelled estradiol contained unconjugated estradiol: conjugated estradiol: conjugated estrone at a ratio of 60: 29: 10, respectively, and at 30 min a ratio of 33: 43: 24. The urinary estrogen metabolites were in the conjugated form with an estradiol: estrone ratio of 60: 40. No radiolabeled estrogen was found in the fecal samples during the 24 hr following administration of the radiolabeled estradiol. These data indicate a rapid clearance of circulating free estradiol in the elephant, with a major metabolite in the serum and urine being estradiol conjugate. © 1992 Wiley-Liss, Inc.     

Blood coagulation profile of the Asian elephant (Elephas maximus)

The coagulation profile of seven Asian elephants was assessed using human reference plasma as a standard. The plasma values for the majority of the coagulation proteins evaluated, including Factors VII, IX, X, and XI, and antithrombin, were similar to that of human plasma. The average Factor VIII:C value was 1.95 units/ml, approximately twice that of the human value. Human recombinant tissue factor was effective as an activator of the tissue factor-factor VII pathway as measured by the prothrombin time assay. The elephant plasma effectively corrected the clotting defect of human Factor XI-deficient plasma but failed to do so with bovine Factor XI-deficient plasma. However, elephant plasma Factor XII was not readily activated by the commercial activated partial thromboplastin time (APTT) reagent formulated with a soluble activator, and consequently the activity of this protein could not be precisely determined. The average (±SD) APTT result of 65.6 ± 9.2 sec was twice as long as that of the human reference plasma. Despite the presence of relatively high levels of fibrinogen, 4.61 ± 0.49 gm/l, no fibrinolytic activity was detected in any of the elephant plasma samples using a standard fibrin plate assay system. © 1996 Wiley-Liss, Inc.     

Identification of bifidobacteria isolated from Asian elephant (Elephas maximus)

Bifidobacteria are considered as one of the key genera in intestinal tracts of animals, and their species composition vary depending on the host. The aim of this study was to identify faecal bifidobacteria from Asian elephants (Elephas maximus), housed in Zoological gardens (Ostrava, Czech Republic). Using culturing, bifidobacteria were found in counts 7.60?±?0.56 log CFU/g. Twenty-six pure strains were isolated from faeces of Asian elephant. The isolates were clustered into two groups according to fingerprinting profiles and fermentation characteristic. Bacteria were identified by a combination of MALDI-TOF MS, PCR methods and sequencing as B. boum (12 isolates) and B. adolescentis (14 isolates). Elephant strains showed different fingerprinting profiles than type and collection strains. Since these two species are frequently isolated from gastrointestinal tract of herbivores, they seem to be typical of animals fed plant diets.     

The effect of some ecological factors on the intestinal parasite loads of the Asian elephant (Elephas maximus) in southern India

Some ecological factors that might potentially influence intestinal parasite loads in the Asian elephant (Elephas maximus Linn.) were investigated in the Nilgiris, southern India. Fresh dung samples from identified animals were analysed, and the number of eggs/g of dung used as an index of parasite load. Comparisons across seasons and habitats revealed that parasite loads were significantly higher during the dry season than the wet season, but were not different between the dry-deciduous and dry-thorn forests in either season. After accounting for the effect of age on body condition, there was no correlation between body condition, assessed visually using morphological criteria, and parasite load in either season. Individuals of different elephant herds were not characterized by distinct parasite communities in either season. When intra-individual variation was examined, samples collected from the same individual within a day differed significantly in egg densities, while the temporal variation over several weeks or months (within a season) was much less. Egg densities within dung piles were uniform, enabling a simpler collection method henceforth.     

Potential factors affecting semen quality in the Asian elephant (Elephas maximus)

Background  

One of the major obstacles in using artificial insemination to manage genetics of elephant population in captivity is the large variations in semen quality among ejaculates within the same and among individuals. The objectives of this study were to determine the influences of (1) age (2) seasonality (3) and circulating testosterone (SrTest), triiodothyronine (SrT3) and tetraiodothyronine (SrT4), as well as seminal (4) testosterone (SpTest), zinc (SpZn) and protein (SpTP) on semen quality in the Asian elephant     

The temporomandibular joint disc of Asian elephant (Elephas maximus) and African elephant (Loxodonta africana)

The temporomandibular joint (TMJ) is a synovial articulation between the mandibular head of the condylar process of the mandible and the mandibular fossa of the squamous temporal bone. Extensions of the fibrous capsule into the joint space form a biconcave disc that functions as an articulating surface and divides the joint into dorsal and ventral compartments. The TMJ disc plays a crucial role in normal functioning of the joint, and differences in cranial morphology, mastication patterns, and diet are reflected in the material and biochemical properties of the disc. The purpose of the present case study was to compare the regional histologic differences between two elephant genera and quantify the biochemical and biomechanical properties of the African elephant disc. This study provides a unique insight into the elephant TMJ disc and also provides a comparison between the African and the Asian elephant genera. The results demonstrate several remarkable findings. First, structure–function relationships exist within the elephant TMJ disc. Second, regional variations exist in the elephant TMJ disc, and these are likely to correlate with its functional requirement. Additionally, it is apparent that some properties of the disc vary with the specific anatomy, diet requirement, and jaw motion. Finally, in comparison with the TMJ disc of other species, it is clear that, although the elephant disc is unique, it has properties that transcend and are preserved among the species.     

Social life of captive Asian elephants (Elephas maximus) in Southern India: implications for elephant welfare

Asian elephants in the wild live in complex social societies; in captivity, however, management often occurs in solitary conditions, especially at the temples and private places of India. To investigate the effect of social isolation, this study assessed the social group sizes and the presence of stereotypies among 140 captive Asian elephants managed in 3 captive systems (private, temple, and forest department) in Tamil Nadu, India, between 2003 and 2005. The majority of the facilities in the private (82%) and temple (95%) systems held a single elephant without opportunity for social interaction. The forest department managed the elephants in significantly larger groups than the private and temple systems. Among the 3 systems, the proportion of elephants with stereotypies was the highest in temple (49%) followed by private system (26%) and the forest department facility (6%); this correlates with the social isolation trend observed in the 3 systems and suggests a possible link between social isolation and abnormal elephant behavior separate from other environmental factors. The results of this study indicate it would be of greater benefit to elephant well being to keep the patchily distributed solitary temple and private elephants who are socially compatible and free from contagious diseases in small social groups at "common elephant houses" for socialization.     

Isolation and characterization of dinucleotide microsatellite loci in the Asian elephant (Elephas maximus)

The endangered Asian elephant is found today primarily in protected areas. We characterized 18 dinucleotide microsatellite loci in this species. Allelic diversity ranged from three to eight per locus, and observed heterozygosity ranged from 0.200 to 0.842 in a wild population. All loci were in Hardy-Weinberg equilibrium, but linkage disequilibrium was detected between two loci in the wild, but not in the zoo elephants. These loci will be useful for the population-level studies of this species.     

Liquid storage of Asian elephant (Elephas maximus) sperm at 4 degrees C

The Asian elephant (Elephas maximus) population in the wild has been in decline for several decades and breeding in captivity has not been self-sustaining. The use of artificial insemination (AI) can help overcome many of the difficulties associated with breeding elephants in captivity; however, the ability to store semen for extended periods of time is critical to the successful application of AI to elephants. The objective of the present study was to assess the effects of four different semen extenders and the presence of egg yolk on the viability and motility of Asian elephant semen stored at 4 °C. High quality ejaculates (n=4) were collected from two Asian elephant bulls by rectal massage. Aliquots of each ejaculate were extended in four different diluents (Beltsville thawing solution (BTS); Tris–citric acid (TCA)/fructose-based; Beltsville F5 (BF5); dextrose-supplemented phosphate-buffered saline (PBS)) with or without egg yolk then cooled and stored at 4 °C. The percentages of viable (viability) and motile (motility) sperm were evaluated at 8, 24 and 48 h following collection. The addition of egg yolk significantly reduced the percentage loss in viability from initial collection to 48 h compared to extenders without egg yolk (17.0±8.2 versus 32.6±8.9 decline in percent viable sperm in the population, respectively; P<0.05). Extender and egg yolk affected (P<0.005) total motility and percent progressively motile sperm at all evaluation times during incubation. TCA + egg yolk maintained higher (P<0.05) levels of progressive motility compared to other extenders supplemented with egg yolk. These results indicate that Asian elephant semen extended in TCA diluent supplemented with egg yolk can maintain at least 50% viability and motility when stored at 4 °C for 48 h.     

基于线粒体DNA的中国亚洲象种群遗传多样性及种群遗传结构

亚洲象是我国国家一级保护动物.本文利用非损伤性取样法,以亚洲象粪便中脱落的肠道上皮细胞为DNA来源,选用线粒体DNA作为分子标记,对分布于我国境内的亚洲象种群的遗传结构和种群遗传多样性进行研究.本研究得到mtDNA序列片段长度为556 bp,经对178个个体进行扩增结果分析,共得到24个单倍型.在5个地理种群中,除南滚河种群外,其他4个种群中的114个个体共享同一单倍型,南滚河种群与其他种群间未观察到共享单倍型.系统发生分析,观察到中国境内现有亚洲象种群在进化上分为两大分支,α和β.其中分支α中包含除南滚河种群外的4个地理种群,分支β仅含有南滚河种群,表明南滚河种群与其他4个地理种群间存在明显分化.遗传多样性分析结果表明,中国境内的亚洲象种群的遗传多样性水平较低,分析原因认为是栖息地破碎化阻断了种群间有效的基因交流.     

Genetic differentiation among local populations of Asian elephant

Electrohoretically detectable enetic variation for 29 kinds of blood protein encoded by 33 loci was analyzed for 78 Asian eletants (Elephas maximus) which were collected from its four local populations: Sri Lanka, Souti India, Thailand and Nepal. Elehants in Sri Lanka are classified into the subspecies E.m. maximus, and those from the other tlree localities into the subspecies E. m. indicus. Six variable loci were detected, and one of them, the tetrazolium oxidase locus, was observed to show a complete allele substitution between the subspecies. Average heterozgosity within local populations were in a range of 0.0152 ? 0.0303. Whereas the Nei's genetic distance among three local populations of the subspecies indicus were 0.0013 ? 0.0031, the distance between the subspecies indicus and maximus were 0.0328 ? 0.0370, indicating that the two subspecies were well differentiated genetically.     

Structural determination of the oligosaccharides in the milk of an Asian elephant (Elephas maximus)

Milk of an Asian elephant (Elephas maximus), collected at 11 days post partum, contained 91 g/L of hexose and 3 g/L of sialic acid. The dominant saccharide in this milk sample was lactose, but it also contained isoglobotriose (Glc(alpha1-3)Gal(beta1-4)Glc) as well as a variety of sialyl oligosaccharides. The sialyl oligosaccharides were separated from neutral saccharides by anion exchange chromatography on DEAE-Sephadex A-50 and successive gel chromatography on Bio Gel P-2. They were purified by high performance liquid chromatography (HPLC) using an Amide-80 column and characterized by 1H-NMR spectroscopy. Their structures were determined to be those of 3'-sialyllactose, 6'-sialyllactose, monofucosyl monosialyl lactose (Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]Glc), sialyl lacto-N-neotetraose c (LST c), galactosyl monosialyl lacto-N-neohexaose, galactosyl monofucosyl monosialyl lacto-N-neohexaose and three novel oligosaccharides as follows: Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-3)Gal(beta1-4)Glc, Neu5Ac(alpha2-6)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)Glc, and Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-3)Gal(beta1-4)Glc. The higher oligosaccharides contained only the type II chain (Gal(beta1-4)GlcNAc); this finding differed from previously published data on Asian elephant milk oligosaccharides.