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The purpose of the study was to determine the effect β₂-adrenergic receptor agonist-clenbuterol on tibiae mineralization of female rats with established osteopenia. The experiments were conducted on 30 female 3-months-of-age Wistar rats with an initial body weight of about 250 g. The sham-operation - SHO (n=10) and bilateral ovariectomy - OVX (n=20) were performed. After 60 days of osteopenia induction the ovariectomized rats were divided into a group fed a standard diet (n=10) and a group that received a diet supplied with clenbuterol at a dose of 5 mg/kg. After 14 days of the experiment the tibiae was isolated and tested using a DEXA densitometer, peripheral quantitative computer tomography (pQCT) and three-point bending test. The obtained results proved that a 14 day period of clenbuterol treatment significantly increased mechanical properties content and mineral density, both planar (BMD) and volumetric (vTotBMD) of the tibiae of ovariectomized rats.
The aim of the present study was to determine the effect of the manner of housing on the growth and mechanical strength of the femur and tibia in heavy (Big 6) and medium-heavy type (BUT 9) turkey-toms. The birds were raised from 7 to 22-weeks-of-age indoors - in a brooder house (traditional system) or under a shelter with access to open-air runs (alternative system). The housing system significantly affected the results of a strength test of femur and tibia. The femurs of turkeys that stayed under a shelter with access to outdoor runs were characterized by higher values of strain, capacity to absorb strength and work to the limit of elasticity and to the limit of maximum resistance. This housing system also had a positive effect regarding the weight of the femur and tibia (increased by 5.9%). Bone strain, capacity to absorb work to the limit of maximum resistance as well as the capacity to absorb strength to the limit of elasticity and to the limit of maximum resistance were affected by the type of turkeys. The weight of the tested bones was higher (by 6.7%) in Big 6 toms. The manner of housing (shelter with access to open-air runs) significantly influenced tibia strain and the capacity to absorb work to the limit of maximum resistance. The change in the housing system was reflected in the values of Young’s modulus and bone weight. Significant differences were also found among the types of turkeys in the capacity to absorb strength to the limit of elasticity and to the limit of maximum resistance as well as in bone weight. The results of femur and tibia strength testing indicate that it is recommended to raise slaughter turkey-toms under a shelter with access to outdoor runs starting from 7-weeks-of-age.
The objective of the study was to determine the effect of a feed mixture of decreased nutritive value in the broiler chickens’ diets on bone resistance parameters and bone mineral composition for Ca, P and Mg. The experiment was conducted on 144 broiler chickens of the cobb line. The chickens were allocated to two feeding groups: control and experimental. Starter mixture, administered till 21-days-of-life was similar for each group. Growth mixture was supplied from the 22nd day. The nutritional value of 1 kg of growth mixtures was 19.5% crude protein and 13.38 MJ EM in the control group, and 19% crude protein and 12.12 MJ EM in the experimental (ecological) group. In the prepared bones, the physical, mechanical and geometrical parameters were estimated, as well as the mineral composition. The lowest bone weight and length was reported for the experimental group as compared to the chickens from the control group. The ecological mixture influenced the bone resistance parameters, which were higher by 12.3% for Wf, 11.9% for Wy, 24.7% for dy and 8.7% for Wf/A in comparison to the control group. The geometrical parameters and cortical bone proved to be higher at the experimental mixture application. The Ca and Mg content in the bones was slightly higher, whereas P content was lower in the bones, yet not confirmed statistically. The introduction of a reduced nutritive value mixture had a positive influence on the studied physical properties, most resistance and geometrical parameters and the mineral composition of broiler chicken tibia bones. It is vital not only for the chicken performance but animal welfare as well. Reduction of the nutritional value in the diets had a beneficial effect on the studied physical and geometrical parameters, as well as on resistance parameters and mineral composition of broiler chicken tibia bones. This fact is of primary importance not only for the production performance but also for the birds’ welfare.
The effect of a decreased level of fodder phosphate in the hens diet contained distillers dried grains with solubles (maize - mDDGS or rye - rDDGS) on laying performance, egg shell quality and mechanical parameters of tibia and humerus was studied in the experiment. It was conducted on 60 Lohman Brown hens from 26 to 68-weeks-of-age. Layers were divided into 5 experimental groups, with each of the 12 hens kept in individual cages. In the control group (I) layers were fed a standard cereal-soybean diet, in the experimental groups diets contained 20% mDDGS (groups II and IV) or rDDGS (groups III and V). The content of total phosphorus in mDDGS was 5.43 g • kg⁻¹ and w rDDGS - 4.95 g • kg⁻¹. Assuming that phosphorus availability in DDGS is high (90%), in groups IV and V the level of fodder phosphate in the diets was decreased by about 40% (from 14 g • kg⁻¹ to 9,5 or 10 g • kg⁻¹). Administering diets containing 20% mDDGS had no effect on laying performance or egg shell and bone quality. In the case of diets with 20% rDDGS a worsening of the laying rate and feed conversion were noted. A decrease of fodder phosphate levels in diets containing DDGS had no negative influence on performance, thickness, density and strength of egg shells and strength, elasticity and stiffness of the tibia and humerus. The obtained results indicated a possibility for decrease of fodder phosphate level in diets containing 20% mDDGS.
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