The effect of caponization on the mechanical properties of Polbar chicken bones was the subject of investigation. The biomechanical strength of bones

Copper (Cu) is required for all basic biochemical and physiological processes. The objective of this study was to compare the effect of two different chemical forms (sulfates and glycinate chelates also below the recommended dose) of Cu administered to adult rats on the biomechanical and morphometric properties of femur. Male rats at the age of 12 weeks were used in the 12-week experiment. The control diet provided the required Cu level from sulfate (S-Cu), and the other diets were supplemented with Cu-glycine complex. The Cu-Gly-treatment, irrespective of its concentration, did not influence the bone mass and length. The Cu-Gly-treatment in 100 and 75% of daily demand increased mechanical endurance. The Cu-Gly-treatment (regardless of its concentration) increased the real bone volume in epiphysis and decreased the total thickness and zone I of the articular cartilage compared to the control group supplemented with S-Cu. The Cu-Gly-treatment enhanced the content of proteoglycans (except the OG50 group). Dietary Cu given to adult rats in the Cu-Gly complex covering the daily demand in 75% exerted a positive effect on bone metabolism and appeared to be the most effective among the investigated doses of the organic form.

The structural quality of the connective tissue is genetically determined and is influenced by hormonal and nutritional modification. An effect of a 2-Ox-rich diet on bone mineralization and structure and expression of non-collagenous protein in articular and growth cartilages of maternal dexamethasone-treated 9-month-old boars was considered in this study. Sows were treated i.m. with dexamethasone at the dose of 0.03 mg kg⁻¹ body weight every second day during the last 45 days of pregnancy. After the birth, the boars were divided into two groups: administered and not supplemented with 2-Ox for 9 months (0.4 g/kg body weight/day). Dexamethasone given during the prenatal time inhibited the growth and negatively influenced the mechanics, geometry and histomorphometrical parameters of long bones and cartilage irrespective of the diet. Moreover, maternal dexamethasone treatment resulted in expression of osteocalcin in the articular cartilage, and the diet rich in 2-Ox limited the OC expression. This study demonstrated that changes observed in adult boars initiated by dexamethasone treatment in the prenatal period were persistent and long-term use of alimentary 2-Ox supplementation can counteract only some of the destructive changes evoked by prenatal dexamethasone excess.