Use of axial X-ray microcomputed tomography to assess three-dimensional trabecular microarchitecture and bone mineral density in single comb white leghorn hens

Use of computed tomography to determine body composition of heavy strain turkey hens (Meleagris gallopavo) from rearing to early laying

Genetic selection has improved the growth performance of poultry, but also influenced other metabolic parameters and physiological functions such as reproduction. To counter the negative effects of this enhanced development, modifications of the environment or diet are frequently used. As all animals are not equally sensitive and do not respond in the same way, the evolution of the body composition has got to be better characterized with non-invasive tools to reach a higher flock homogeneity and improve production yield. Thus, we have analyzed turkey breeder hens' body composition using computed tomography scan and measurements of biochemical markers from 16 to 34 wk old. During rearing, body weight was strongly correlated to muscle, fat, and bone volumes (r > 0.75), and increased with hen age until sexual maturity (31 wk). These correlations did not maintain after photostimulation was initiated (29 wk). Muscle volume linear regression with hen age resulted in a R² value of 0.626 over the whole trial study. Bone volume was better fitted by a quadratic regression (R² = 0.7) and was proportional to calcium plasma level evolution, both increasing after 28 wk of age. Conversely, fat volume quadratic regression (R² = 0.5) was symmetrical to triglyceride levels, the first decreasing notably at sexual maturity, the other increasing massively after 28 wk. Egg, yolk, and albumen weights increased with hen age, as did yolk triglyceride levels. In conclusion, computed tomography allows to investigate turkey breeders' body composition and bring new data in the genetic selection strategy. In addition, the evolution of the fat deposition and bone changes have been monitored over time and could help to optimize breeders' diet strategy.

Computer-generated radiological imagery of the structure of the spongious substance in the postnatal development of the tibiotarsal bones of the Peking domestic duck (Anas platyrhynchos var. domestica)

The evaluation of the structure of the spongious substance of the tibiotarsal (TT) bones of the domestic duck aged 4 to 8 wk was performed using radiological analysis. The Trabecula program (Czerwiński, 1994) used in the study identified a map of radiological trabeculae and calculated the number, average volume, density, and width of trabeculae. It was stated that the number of trabeculae differed significantly (P ≤ 0.05) variant on age, sex, and a unique fragment of the studied bone. Six-week-old hens whose TT bones were most often exposed to deformities and fractures possessed attenuated bone mass. The number of trabeculae per 1 mm(2) during breeding was the lowest (10.34 and 9.54 mm(2) in the proximal and distal epiphyses, respectively). The tibial bones of the 6-wk-old hens also possessed the lowest volume of trabeculae (44.62 and 39.84% for the proximal and distal epiphyses, respectively). Dependant variances between the BW, the number of recognized radiological trabeculae, and the volume, density, and width of trabeculae were calculated using a selected correlation and regression coefficient (r = 0.41; P ≤ 0.05). Results expounded a unique linear relationship between BW and the volume of trabeculae. Indeed, the larger the BW, the more numerous the trabeculae observed. No significant correlation was determined between the BW and the number of recognized trabeculae nor their density and width. A small number of trabeculae and the lowered density may be the cause of fractures and deformities of the TT bones of the domestic duck.