| African Ostrich is the existing biggest birds, originated from African grassland and Arabian desert, and is classified within the kingdom Animalia, phylum of Chordata, class of Aves, superorder of Paleognathae, Struthioniformes order of ratites, genus of Struthio, and family of Struthionidae. Adult ostriches are 240-280cm high and 130-200kg weight, have long legs with developed muscle. The ostrich has lost flying ability, but running at speed around 50 km/h, and the top is 90～100 km/h. It is inferred that ostrich shank would have special structure compared with other birds. Some studies have indicated ostrich skeletal characteristics, but seldom further reports.Tibia fracture occurs on the ostrich chicks under 6 months frequently, which reduces the economic benefits of ostrich breeding. The main reason for tibia fracture is nutritious factors, including the diet calcium, phosphorus and vitamin D deficiency, inappropriate diet calcium phosphorus proportion, or nutrition uptake repression. These reasons cause osteoporosis in ostrich chicks, which induces leg diseases (eg. tibia fracture or transformation). Ostrich leg disease occurs frequently, and cause economic losses in ostrich husbandry. There are some researches about ostrich leg diseases resently, but the problem is still not solved.Boron, atomic number is 5, atomic weight is 10.811. More and more evidence shows that boron can promote the growth of bones. Boron may influence cartilage and bone structure, vitamin D metabolism and minerals metabolism, for instance. It can increase the bone mass and the ability of anti-fracture, can improve the ash content in the femur of calcium and magnesium deficiency rats, can improve metabolism of blood calcium and phosphorus, and copper and zinc. But high dosage of boron would also bring adverse effects on animal development and reproduction. There are no reports referred to the effects of boron on ostrich bone development at present.For the above 3 reasons above, this article is about the research of morphology of ostrich tibia, tibia development in ostrich chick, pathological change of leg disease ostrich tibias, and the effects of boron on ostrich tibia development by using anatomy, bone grinding chip(crystalline violet stain), scanning electron microscopy (SEM), bone demineralization paraffin section(HE stain), two-dimensional difference gel electrophoresis(2-D DIGE), apoptosis detection and image analysis technology, bone density determine, radiation immune method, atomic absorption spectrophotometric, flow injection analysis comprehensive method, etc., aiming to provide fundamental research and theoretical foundation for disease control and prevention of ostrich (especially nestlings). The main contents and results of this research include the following 4 aspects:1. Morphology characteristics of African Ostrich tibia1-year-old African ostriches are used in the study to investigate the morphological structure of tibia, by the experiments of anatomy, bone grinding chip (crystalline violet stain), scanning electron microscopy(SEM), bone demineralization paraffin section(HE stain), bone density determination. Result shows that:the bone mineral density of the experimental animals is very high (5.656 g/cm2), and the bone mineral density on different parts of tibia are significantly different. Ostrich tibia is very hard with plenty of mineral deposited. There is a transform area stained specially between outer circumferential lamella and osteon area. In addition, ostrich tibial distal joints cannot left-right rotate as human, these anatomic features may be more advantageous for bearing and improving the running speed.2. Developmental characteristics of ostrich chick tibia1,45,90 days old ostrich chicks are used in this study to investigate the morphological structure of tibia of ostrich chicks, by the experiments of anatomy, scanning electron microscopy(SEM), bone demineralization paraffin section(HE stain), bone density determination. Result shows that:ostrich chicks under 90 days grow very fast, and the length, weight, bone mineral density (BMD) of the tibia all increase significantly and continuously. In the tibia of 1-day-old bird, transitional bone trabeculae constitute the primary cancellous bone, which constitute the early formation of backbone. In the tibia of 45-day-old bird, resorption is very active, transitional bone trabeculae are absorbed by osteoclasts and then rebuilded. In thetibia of 90-day-old bird, rudiment of new born compact bone and osteons already exists, but the mature bones are still not formed. Therefore, in the young ostrich husbandry, nestlings should be kept in a good feeding environment and the feed should be given at a reasonable nutrition proportion to meet the needs of the tibias growth of ostrich chicks.3. Differences between tibias from normal and leg disease ostrich chicks90 days old normal and leg disease ostrich chicks were used in the study to investigate the difference of morphological structure and protein content between disease bird tibia and the normal one, by the experiments of anatomy, scanning electron microscopy(SEM), bone demineralization paraffin section(HE stain), bone density determine and protein two-dimensional electrophoresis technology. Result shows:bone mineral density value of leg disease birds is much lower than the normal one. In the disease tibia, compared with normal tibia, there are less bone trabeculae, which are attenuated and began to disappear. In addition, great number of absorb pits are observed on the surface and micro-fracture appears on bone trabeculae. These results indicate that, the disease tibia has less bone density and trabeculae micro-fracture happens in tibia with different disease. Furthermore, the samples of normal group and leg-disease group are detected by two- dimensional difference gel electrophoresis (2-D DIGE). And the 2-D DIGE results are analyzed to screen out 154 differentially expressed protein spots with more than 1.5 times of significance(P<0.5).4. Effects of boron on the development of ostrich chick tibia90 days old ostrich chicks were used in the study to investigate the effects of boron on ostrich chick tibia development, by the experiments of scanning electron microscopy (SEM), bone demineralization paraffin section(HE stain), apoptosis detection and image analysis technology, bone density determination, radiation immune method, atomic absorption spectrophotometric, flow injection analysis comprehensive method, etc.. Result shows that:with different dosage of additional boron, the ostrich serum calcium and boron level are decreased, but serum calcium phosphate ratio increased, serum leptin levels gradually raised, estradiol level in Group C slightly higher than Group A, Bone density value, length, ash, etc all were improved. Group B has highest body weight, B and C group tibial length numerical highest, Group C tibial weight is highest, Group C, D has more ash content, Group C has highest BMD, Group A and C has less apoptosis cells. In conclusion, it was support that ostrich chick tibias in group C grow best, and the most suitable dosage for the development of tibia is 200 mg/L. However, the real optimum dosage of additional boron still needs further gradient experiments to ascertain to effectively apply in animal production.
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