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Um experimento foi conduzido no Setor de Avicultura do Departamento de Nutrição e Produção Animal da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo para avaliar o efeito de rações contendo diferentes níveis de cálcio e suplementadas com fitase sobre o desempenho, a digestibilidade e a excreção de nutrientes pelas aves, determinar a energia metabolizável aparente corrigida e avaliar a mineralização óssea de frangos de corte nas fases inicial (1 a 21 dias), de crescimento (22 a 35 dias) e final (36 a 42 dias). No ensaio de desempenho foram utilizados 2.160 pintos de corte machos da linhagem AG Ross 308, de 1 a 42 dias de idade, distribuídos em 6 tratamentos, com 6 repetições cada. Foi utilizado um delineamento inteiramente casualizado em esquema fatorial 3 x 2, sendo 3 níveis de fitase (0, 600 e 1200 FTU/kg) e 2 níveis de cálcio (0,94% e 0,66%; 0,84% e 0,59%; e 0,78% e 0,54% para as fases inicial, de crescimento e final, respectivamente). As rações experimentais ainda tinham níveis reduzidos de fósforo disponível (Pd) e níveis mínimos de proteína bruta (PB). Ao final de cada fase avaliou-se o consumo de ração (CR), o ganho de peso (GP), a conversão alimentar (CA) e a mortalidade (Mort). Não houve interação entre os níveis de fitase e de cálcio estudados para CR em nenhuma das três fases avaliadas, entretanto foram observadas para GP (P<0,01 para a fase inicial e P<0,05 para as fases de crescimento e final) e para Mort (P<0,01 para as fases inicial e de crescimento e P<0,05 para a fase final) nas três fases. Foram observados efeitos de fitase para o CR (P<0,01 para ambas as fases) na fase inicial e de crescimento e os níveis de cálcio influenciaram o CR (P<0,05 para ambas as fases) nas fases inicial e final. Nenhum resultado significativo foi observado para CA. Desse modo pode-se concluir que os níveis nutricionais de cálcio podem ser reduzidos em 30% em dietas com níveis reduzidos de fósforo disponível e níveis mínimos de proteína bruta, sem afetar o desempenho, desde que às dietas sejam adicionadas 600 FTU/kg de fitase. Paralelamente foram conduzidos 3 ensaios de metabolismo utilizando-se 108 pintos de corte machos transferidos do galpão de alvenaria para as baterias metálicas aos 15, 29 e 36 dias, respeitando-se os tratamentos e as repetições, onde passaram por um período de 4 dias de adaptação, e 3 dias de coleta de excretas. Neste ensaio avaliou-se a energia metabolizável aparente corrigida (EMAn), o consumo, a excreção e o coeficiente de retenção de nitrogênio (N Ing, N Exc e CR N), fósforo (P Ing, P Exc e CR P) e cálcio (Ca Ing, Ca Exc e CR Ca). Nenhuma resposta significativa foi observada para EMAn na fase inicial. Interações entre os níveis de cálcio e de fitase foram observadas para EMAn nas fases de crescimento (P<0,01) e final (P<0,01), sendo os maiores valores observados para níveis de fitase próximos a 600 FTU/kg, para baixo e alto nível de cálcio, respectivamente. Para o metabolismo de nitrogênio foram observadas interações entre os níveis de cálcio e fitase para N Ing nas fases de crescimento (P<0,01) e final (P<0,01), N Exc na fase de crescimento (P<0,01) e CR N nas fases de crescimento (P<0,01) e final (P<0,05). Os níveis de fitase influenciaram o N Ing (P<0,01) e N Exc (P<0,05) na fase inicial, e os níveis de cálcio influenciaram o N Ing (P<0,05) na fase inicial. Nenhum resultado foi observado para N Exc na fase final e nem para CR N na fase inicial. De uma maneira geral, a redução do nível de cálcio associada a 600 FTU/kg de fitase na fase de crescimento, e alto nível de cálcio associado a 1200 FTU/kg de fitase para a fase final, apresentam os melhores resultados. Para o metabolismo de fósforo foram observadas interações entre os níveis de fitase e cálcio estudados para P Ing (P<0,01 e P<0,05, respectivamente) nas fases inicial e final, e para CR P (P<0,01 e P<0,05, respectivamente) nas fases inicial e de crescimento. Os níveis de fitase influenciaram o P Ing (P<0,01) na fase de crescimento e o CR P (P<0,05) na fase final; e os níveis de cálcio influenciaram o P Ing (P<0,01) na fase de crescimento. Nenhum resultado significativo foi observado para P Exc em nenhuma das três fases estudadas. A adição de 1200 FTU/kg de fitase à dieta melhora significativamente a retenção de P, seja na fase inicial, associada a um baixo nível de cálcio, ou na fase de crescimento. Para o metabolismo de cálcio foram observadas interações entre os níveis de fósforo e cálcio estudados para Ca Ing (P<0,01 para ambas as fases) nas fases de crescimento e final e para CR Ca (P<0,05) na fase de crescimento. Os níveis de fitase influenciaram o Ca Ing (P<0,01) e o CR Ca (P<0,01) na fase inicial; e os níveis de cálcio influenciaram o Ca Ing (P<0,01) e o CR Ca (P<0,01) na fase inicial, o CR Ca (P<0,01) na fase final e o Ca Exc (P<0,01) nas três fases estudadas. De uma maneira geral, os melhores resultados foram encontrados com a redução de 30% dos níveis de cálcio associados à adição de 600 FTU/kg de fitase na dieta. Dessa maneira conclui-se que nas fases inicial e de crescimento, a redução do nível de cálcio da ração em 30% utilizando baixos níveis de fósforo disponível e proteína bruta com adição de 600 FTU/kg de fitase na dieta é adequada para a melhora da EMAn, da retenção de nitrogênio, fósforo e de cálcio. Já, para a fase final, a redução do nível de cálcio não é aconselhada, porém a inclusão de 600 FTU/kg de fitase na dieta melhora a EMAn e a retenção de nitrogênio. Para o ensaio de mineralização óssea, foram utilizados 72 frangos de corte machos, que foram sacrificados e tiveram suas tíbias esquerdas retiradas ao final de cada fase. Foram avaliadas as quantidades (mg) e porcentagens de matéria mineral (MM T e %MM T), fósforo (P T e %P T) e cálcio (Ca T e %Ca T) das tíbias. Houve interação entre os níveis de cálcio e de fitase apenas para a %MM T na fase inicial (P<0,05), provavelmente devido à maior exigência de minerais para a formação óssea nessa fase. Os níveis de fitase influenciaram de maneira linear crescente o MM T (P<0,01) e a %P T (P<0,05) na fase inicial e o P T (P<0,05) e o Ca T (P<0,05) nas fases inicial e de crescimento; e de maneira quadrática o MM T (P<0,01) e a %MM T (P<0,01) nas fases de crescimento e final. Não foi observada nenhuma resposta significativa para %Ca T. Estes resultados permitem concluir que o nível de cálcio pode ser reduzido em 30% em dietas com níveis reduzidos de Pd e níveis mínimos de PB para frangos de corte de 1 a 42 dias, desde que às dietas sejam adicionadas 1200FTU/kg de fitase. / An experiment was carried on Poultry Sector of Animal Nutrition and Production Department of Veterinary Medicine and Animal Science School of São Paulo University to evaluate the effect of diets with different calcium levels and supplemented with phytase on the performance, digestibility and nutrient excretion, determine the corrected apparent metabolizable energy and evaluate bone mineralization of broiler chickens in initial (1 to 21 days of age), growing (22 to 35 days of age) and final (36 to 42 days of age) phases. In performance essay it was used 2,160 male broilers from AG Ross 308 line, from 1 to 42 days of age, distributed in 6 treatments, with 6 replicates each. A completely randomized design in a 3 X 2 factorial schedule was used, being 3 phytase levels (0, 600 or 1200 FTU/kg) and 2 calcium levels (0.94% and 0.66%; 0.84% and 0.59%; and 0.78% and 0.54% to initial, growing and final phases, respectively). The experimental diets had lower available phosphorus (AP) levels and minimum crude protein (CP) levels. At the end of each phase the feed intake (FI), weight gain (WG), feed conversion (FC) and death rate (DR) were evaluated. There was no interaction among phytase and calcium levels to FI on any of the three studied phases, however they were observed to WG (P<0.01 to initial phase and P<0.05 to growing and final phase) and to DR (P<0.01 to initial and growing phase and P<0.05 to final phase) on the three phases. It was observed effects of phytase to FI (P<0.01 to both phases) on initial and growing phases, and calcium levels influenced FI (P<0.05 to both phases) on initial and final phases. No significant results were observed to FC. Thus it can be concluded that nutritional calcium levels can be reduced in 30%, in diets with lower AP and minimum CP levels, without affecting performance, since to the diet is added 600 FTU/kg of phytase. At the same time were carried three metabolism trials using 108 male broilers transferred from experimental house to metal batteries at 15, 29 and 35 days of age, respecting both treatments and replicates, where they passed through a period of 4 days of adaptation and 3 days of excrete collection. In this essay were evaluated the corrected apparent metabolizable energy (AMEn), the consumption, excretion and the retention coefficient of nitrogen (N C, N E and N RC), phosphorus (P C, P E and P RC) and calcium (Ca C, Ca E and Ca RC). No significant response was observed to AMEn on initial phase (P<0.01). Interactions among calcium and phytase levels were observed to AMEn on growing (P<0.01) and final (P<0.01) phases, being the higher values observed to phytase levels near to 600 FTU/kg, to low and high calcium levels, respectively. To nitrogen metabolism, it were observed interactions among calcium and phytase levels to N C on growing (P<0.01) and final (P<0.01) phases, N E on growing (P<0.01) phase and N RC on growing (P<0.01) and final (P<0.05) phases. Phytase levels influenced N C (P<0.01) and N E (P<0.05) on initial phase, and calcium levels influenced N C (P<0.05) on initial phase. No significant results were observed to N E on final phase neither to N RC on initial phase. In a general way, the calcium level reduction associated to 600 FTU/kg of phytase on growing phase, and high clacium level associated to 1200 FTU/kg of phytase on final phase, show the best results. To phosphorus metabolism were observed interactions among calcium and phytase levels to P C (P<0.01 and P<0.05, respectively) on initial and final phases, and to P RC (P<0.01 and P<0.05, respectively) on initial and growing phases. Phytase levels influenced P C (P<0.01) on growing phase and P RC (P<0.05) on final phase; and calcium levels influenced P C (P<0.01) on growing phase. No significant results were observed to P E in any of the studied phases. Adding 1200 FTU/kg of phytase to the diet improves P retention on initial phase, associated to low calcium level, or on growing phase. To calcium metabolism were observed interactions among calcium and phytase levels to Ca C (P<0.01 to both phases) on growing and final phases and to Ca RC (P<0.05) on growing phase. Phytase levels influenced Ca C (P<0.01) and Ca RC on initial phase; and calcium levels influenced Ca C (P<0.01) and Ca RC (P<0.01) on initial phase, Ca RC on final phase and Ca E (P<0.01) on the three studied phases. In a general way, the better results were found reducting calcium levels in 30% associated to 600 FTU/kg of phytase on diet. So, it can be conclude that, on initial and growing phases, calcium levels reduction in 30%, using low AP and CP levels with 600 FTU/kg of phytase on diet is adequate to improve AMEn, N, P and Ca retention. However, to final phase reducting calcium level is not recommended, even so, adding 600 FTU/kg of phytase on diet improves AMEn and N retention. To bone mineralization essay were used 72 male broilers that were slaughtered and their left tibia removed at the end of each phase. It were evaluated tibia quantity (mg) and percentages of mineral matter (MM T and % MM T), phosphorus (P T and %P T) and calcium (Ca T and % Ca T).There was interaction among calcium and phytase levels only for %MM T on initial phase (P<0.05), probably due to higher mineral requirement to bone forming in this phase. Phytase levels influenced on a linear increasing way the MM T (P<0.01) and %P T (P<0.05) on initial phase, and P T (P<0.05) and Ca T (P<0.05) on initial and growing phase; and on a quadratic way the MM T (P<0.01) and %MM T (P<0.01) on growing and final phase. There was no significant response to %Ca T. These results allowed to conclude that calcium level can be reduced in 30% in diets with lower AP and minimum CP levels to broiler chickens from 1 to 42 days of age, since 1200 FTU/kg of phytase are added to the diet.

Background Running is a popular form of exercise that more than 55 million Americans actively participate. Endurance running like marathon and half- marathon is getting increasingly popular among active runners. Although the effect of running is considered beneficial to bone health, the direct relationship between strains and strain gradients occurred during long distance running and bone changes is still not clear. Especially, given a high rate of injury associated with the first-time marathon, understanding the direct effect of strain stimuli on bone health is an important issue. Based on the previous studies, we hypothesized that the higher values of strain will induce bone adaptation more effectively and will lead to higher bone osteogenic changes. Since osteocytes sense shear stress caused by the interstitial fluid flow, which is created by the deformations, and regulate activities of osteoblasts and osteoclast that govern bone adaptation, we also hypothesized that the local strain gradient will create pressure differences within the interstitial fluid network and will increase fluid flow. Furthermore, due to that increased fluid flow, the regions with the higher strain gradient will experience a higher amount of bone adaptation. Thus, in this study, our purpose was to define the effect of the strains and strain gradients on bone changes within distal tibia, which is the most prone anatomical site to low risk stress fracture, during training for first-time marathon. Methods High-resolution and low-resolution computed tomographic (CT) images of the distal tibia were obtained before and after a self-selected training from runners who were actively training to participate in their first-time marathon in the next calendar year. The low resolution scan covered a 69.864 mm length of the distal end of the tibia while the high resolution CT scan covered a 9.02 mm region of the distal tibia. Using low resolution CT image based subject specific finite element (FE) models, the strains and strain gradients of the distal tibia at the instance of the peak ground reaction force (GRF) were calculated. The baseline and follow-up high resolution CT scans were used in high resolution peripheral quantitative CT (HRpQCT) analysis and the estimation of bone changes over the training period. Finally, the effect of strains and strain gradients on the distal tibia bone changes was estimated based on the FE model driven strain values and HRpQCT analysis driven bone changes. We used a linear mixed model to define the relationship between strain values and bone changes in the distal tibia. Results The strain values that occurred during marathon training had significant effects on bone changes in the distal tibia. Particularly, the strain gradients showed a higher effect than the strains. In the cortical compartment, the strain gradients, which were calculated as a strain difference of a node from the surrounding nodes (Strain Gradient-1), affected the bone mineral density (BMD) negatively, and per 1000 µε increase resulted in 2.123% decrease in the cortical BMD. The strain gradients, which were calculated as a strain difference of a node from the surrounding nodes normalized to distance to surrounding nodes (Strain Gradient-2), presented a positive effect on the cortical bone volume with a slope of 4.335% / 1000 µε. In the trabecular compartment, the strain gradient-1 showed negative effects on the percent change in BMD and bone mineral density (BMC), whereas the strain gradient-2 showed positive effects on the percent change in BMD and BMC. Conclusion The linear mixed model analysis revealed a statistically significant (p < 0.05) relationship between strain gradients that occurred during running and distal tibia bone changes. The strains, biometrics, and initial parameters of bone did not show any significant effect on the bone changes. The connection between local strain environment and bone changes in the distal tibia investigated in this study is an important step to understand the mechanism of mechanically induced bone adaptation.

No description available.

Past literature has supported the supplementation of 25-OHD3 into poultry diets to reduce leg issues and improve muscle accretion. In addition, exogenous feed enzymes are included into poultry diets to increase nutrient utilization. The first objective of this thesis was to determine the effects of different sources and levels 25-OHD3 supplementation on D0-53 Ross x Ross 708 male broiler performance, processing yield, tibia ash, serum Ca and 25-OHD3 status. Data demonstrated that 25-OHD3 supplementation into diets with Low VitD3 (165 IU/kg) can improve broiler performance compared to High VitD3 (2756 IU/kg). The second objective was to investigate the effects of varying phytase inclusion with different xylanase levels on D0-56 Ross x Ross 708 male broiler performance, processing yield and tibia ash. Data exhibited some performance benefit (D46 and D56) when utilizing phytase (1000 and 1500 FTU/kg) with 1500 EPU/kg xylanase and phytase (250 and 1500 FTU/kg) with 3000 EPU/kg xylanase.

The effects of varying dosages of 25-hydroxycholecalciferol [25(OH)D3] in commercial diluent injected into the amnion of developing broiler embryos were investigated in a preliminary trial and 2 consecutive main trials. Evaluation of the results of the preliminary trial showed that the in ovo injection of 0.60 micrograms of 25(OH)D3 is capable of increasing its subsequent levels by approximately 3 fold in the circulation of broiler embryos on 19.5 days of incubation. Similarly, results of the 2 main trials showed that the in ovo injection of 0.60 micrograms of 25(OH)D3 significantly improved hatchability on day 21 of incubation and the subsequent performance and bone characteristics of broilers through 28 days of post-hatch age. In conclusion, it is suggested that the in ovo injection of 25(OH)D3 at a 0.60 micrograms dose may be used to effectively improve hatchability, and the performance and bone characteristics of Ross ~ Ross 708 broilers.

Introduction: Below knee amputation is the safest treatment for aggressive benign and malignant bone tumours of the distal tibia yielding good oncological and functional results. However, in selected patients where limb salvage is feasible and amputation unacceptable to the patient, limb salvage using a distal tibial replacement (DTR) can be considered. This study aims to present the oncological and functional results of the use of this treatment method in our unit. Patients &amp; Methods: A retrospective folder review was performed for all 10 patients who received a modular distal tibial replacement between 01/01/2005 and 31/01/2019 for a primary bone tumour either benign aggressive or malignant. Six were female and the mean age was 31 (1275) years. There were five patients with giant cell tumour of bone, four with osteosarcoma and one with a low-grade chondrosarcoma. The patients with osteosarcoma had neo-adjuvant chemotherapy before surgery. Function was assessed by the Musculoskeletal Tumor Society (MSTS) score. Results: There were six females and four males, with a mean age of 31 (12-75) years. Two patients had local recurrence treated with a BKA and one other patient died of metastases three years postoperatively. At a mean follow-up of three years, the remaining eight patients had a mean MSTS score of 83% (67–93%). There were no radiological signs of loosening, and no revision surgeries. Conclusion: Endoprosthetic replacement of the distal tibia for primary bone tumours can be a safe treatment option in very selected cases.

The purpose of this study was to investigate the influence of tibial stem geometry on stress shielding of the tibia for patients with a total knee replacement. Finite element analysis was used to study different tibial stem geometry types, as well as a vast array of different geometric sizes. Both a peg and stem type geometry were analyzed and compared in order to determine what type geometry causes the least amount of stress shielding. A static loading condition with a dynamic loading factor of three was used for the system and the stress responses were analyzed at regions of interest at various depths. Regions of interest include the posterior and medial regions, at depths ranging from the resurfaced tibial surface to 100 mm below the surface. It was found that the smallest stem/peg sizes produced the least amount of stress shielding, indicating that the less amount of foreign material within the tibia, the more natural the bending and stress response of the tibia. It was also concluded that for the loading conditions used in this study, peg type geometry yields a decreased amount of stress shielding when compared to stem type geometry. This is due to the fact that the peg type geometry allowed for more natural bending and a distributed loading transfer between two pegs rather than one long central stem. Further studies should be completed on other geometry types in order to understand how to best replicate the natural bending of the tibia.

No description available.