We studied the effect of experimental hypodynamy on the structure of the two long bones (femur and tibiotarsus) of adult Japanese quail (Coturnix coturnix japonica) with special regard to osteoclasts. The quails were 70-day-old at the beginning of the experiment, they were euthanized after 28, 56, and 84 days of hypodynamy. Small pieces of bones were fixed, decalcified in EDTA, and routinely processed further for light and transmission electron microscopy. Structural changes in spongy bone and in the osteoclasts were found in all the experimental animals, compact bone was not affected. It seems that osteoclasts respond biphasically. First, after 28 days of hypodynamy, the number of osteoclasts diminished; they became vacuolated and had ruffled borders poor in microvilli. After 56 days of hypodynamy the osteoclasts recovered and became more numerous than in control animals; these osteoclasts possessed fully developed ruffled borders with many microvilli. After 84 days of hypodynamy the osteoclasts covered nearly the whole surface of the bone spicules and showed structural signs indicating their full activity.Japanese quail, experimental hypodynamy, osteoclasts, spongy bone, light microscopy, transmission electron microscopy

Bocfa K., V. Sabo, M. Jurani, T. S. Guryeva, J. Kocisova, E. Kostal, A. Laukova, O. A. Dadasheva: Embryonic Development and Behaviour of Japanese Quail Expored to Microgravi~v. Acta vet. Bmo, 61, 1992: 99-107. .The effect of microgravity on the embryonic development of Japanese quail including hatching, the behaviour of newly hatched chickens and physiological functions of adult birds were studied. The feasibility of the entire embryonic development as well as hatching of quail in weightlessness was demonstrated. Priority data on sensory, motor and feeding behaviour of 1-to 4-day-old quail hatchlings as well as the behaviour of adult birds in microgravity were obtained. Under special conditions the quail were able to take food, but were generally Unable to adapt their motor activity to microgravity at any time during the experiment. Their movements were uncoordinated and chaotic, particularly so in chicks. After a 7-day exposure to microgravity hormone levels (estradiol, triiodthyronine, corticosterone) and Ca in mature quail were determined. Changes in reproductive functions were manifested by the arrest of egg production, dystrophy of ovaries and testes and a decreased testosterone level. The first data on the effects of microgravity on the enteric microflora were also obtained. Japanese quail, microgravity, embryogenesis, behaviour, hormones, enteric microbiologyThe establishment of biological systems utilizing animals to suppOfi the life of cosmonauts during long-term missions in orbital and planetary stations has become an object of the general study of cosmic biology (Shepelev 1975).The animals selected should have a higher heterotrophic link in the self-sustaining ecosystem and will be required to live and produce under conditions of microgravity. The first experimental goal to meet these criteria is to study the potencial for the avian mod~1. Due to its relatively low body mass and high performance converting feed to meat, the Japanese quail has been used (Boda 1979).Since 1973 a series of experiments was conducted in which biological as well as technological problems, aimed at the realization of flight experiments, were undertaken. These experiments included adaptation mechanisms of quail to changed gravity (Jurani et al. 1980) problems connected with overcoming stress caused by the transport to orbit (Peter et al. 1978), the effect of long-term hypodynamy on the performance and breeding of a line of quail resistant to hypodynamy (Jurani et al. 1988).Technological preconditions to study the entire reproductive cycle of the birds under the microgravity of Earth-orbital flight were provided by the construction and production of the devices incubator 1 (Sutek et al. 1984; Soucek et al. 1984), Incubator 1M and NEST (Maiek andZongor 1991).Results obtained in these experiments have become the starting point to study avian microgravity under real space flight conditions.Experiments were designed to determine the effect of microgravity on the embryonic development of Japanese quail including hatching, ...

The effect of microgravity on functional development of the small intestine of Japanese quails incubated for 2-3 d and hatched on the orbital station MIR was examined. After 5 d of space flight duodenal and jejunal alkaline phosphatase (AP) activity of the experimental group was compared with the AP activity in quails of the same age hatched on the Earth (laboratory controls). Shortterm microgravity leading to decreased food intake resulted in significant increase of AP activity in both duodenal and jejunal enterocytes (P < 0.001) of the experimental quails. The results suggest that increased AP activity probably reflects the delayed functional development of the small intestine as a consequence of inapropriate food intake during non-physiological conditions of space flight. Microgravity, posthatch quail, alkaline phosphatase, food intake, fasting

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