Techniques for hand‐rearing tree‐shrews (Tupaia belangeri) from birth

Abstract

In captivity, Tupaiu belungeri (Thailand tree-shrew) frequently show aberrant patterns of maternal care which result in the death of offspring. In order to maximize the potential of the tree-shrew as an animal resource for experimental studies we have developed a program for hand-rearing tupaiidae from birth. Newborn tree-shrews were removed from mothers with a history of poor parental care to a nursery maintained under conditions of controlled relative humidity (70 5 10%) and temperature (25 1 O C) on a 12 h dark: 12 h light cycle. The young tree-shrews were fed on a liquid formula until the eyes opened (Day 18-23) and for the subsequent 10 days on a transitional diet until they could feed themselves on solid food. Our hand-rearing protocol appears to conform to the natural weaning pattern of tupaiids. Food consumption during the liquid diet phase was linearly related to age and the increase in body weight in both sexes. The initial growth rate of male and female hand-reared tree-shrews was slower than that of maternally reared animals during the liquid diet phase. The growth rate accelerated subsequently and the body weight of hand-reared tree-shrews eventually reached that of maternally reared animals of the same sex. Various developmental changes occurred during the same period in artificially and naturally reared animals. In both hand-reared and maternally reared groups, the growth rate of male treeshrews exceeded that of females from about Day 40 onward. The accelerated growth rate of male tree-shrews was in apparent association with an increase in androgen secretion at the onset of puberty. The high fecundity of tree-shrews in captivity reinforced with a program for hand-rearing the young make T belungeri a potential alternative to more conventional laboratory species in specific areas of biomedical research.

Endocrine correlates of reproductive development in the male tree-shrew (Tupaia belangeri) and the effects of infantile exposure to exogenous androgens

“…Viewed in these terms, puberty in the tree-shrew is initiated at about Day 30 and is heralded by the reappearance of differentiated Leydig cells in the testis and the earliest indications of elevated testosterone levels in the blood and urine (Collins et al, 1989). At this time the young are weaned and emerge from the nest (Tsang and Collins, 1985). The current study establishes that levels of reproductive hormones remain low during this period (Fig.…”

“…Throughout this infantile phase, the young occupy a separate nest from their parents and are dependent on milk provided on brief suckling visits by the mother (Tsang and Collins, 1985). Infant tree-shrews show a lack of differentiation of the accessory sex organs, secondary sexual characteristics and the testicular sex cords .…”

“…Male tree-shrews bred from stock originating in Thailand were housed and hand-reared in accordance with the NIH Guidelines for the Care and Use of Laboratory Animals, as previously described (Tsang and Collins, 1985). The experimental procedures were approved by the Institutional Animal Care and Use Committee at UCSB.…”

“…As such, they are an important, albeit outlying, group in the study of primate phylogenetics (Sargis, 2004). An examination of the reproductive biology of the male South-east Asian tree-shrew, Tupaia belangeri, has revealed that the structure of the reproductive tract (Collins et al, 1982) and the developmental life-history (Tsang and Collins, 1985; in this species conforms with the general primate pattern. As in primates, the infantile phase of development in tree-shrews is extended compared with mammals of similar size, such as rat, so that puberty occurs towards the end of somatic differentiation in association with a phase of maximum body growth.…”

‘Schultz's Rule’ and the evolution of tooth emergence and replacement patterns in primates and ungulates

“…In one case (Tupaia), an unknown age of emergence of M 1 was estimated with some confidence. It is known that the entire permanent dentition erupts between about 1 and 3 months of age in Tupaia (Shigehara, 1980;Tsang and Collins, 1985;Herten stein et aI., 1987). Further, it is likely that M 1 appears after completion of the deciduous dentition (day 27) and before males begin puberty (day 40-50).…”