RESUMO
Coccidiosis is one of the main challenges for the worldwide poultry industry, and several anticoccidial treatments have been used to fight these protozoa. Resistance of Eimeria parasites against anticoccidials-and the public opinion about these treatments-demands for alternatives. In this trial, we tested Yucca schidigera (500 g/T) as a natural alternative in broilers challenged with Eimeria. This treatment was compared to three other treatments: An unchallenged control, a challenged control, and a challenged anticoccidial (625 g/T) treatment with focus on performance, oocyst per gram counts (OPG), and lesion scores. Both the anticoccidial and the Yucca schidigera group showed significant improvement in body weight (2.150 and 2.058 vs. 1.998 and 1.971 kg). growth (60.2 and 57.6 vs. 55.8 and 55.1 g/d). and feed-conversion ratio (1.456 and 1.510 vs. 1.527 and 1.575), compared to both control groups. No significant differences were found between the treatments on OPG collection days 18 and 25. On day 35, lowest OPG counts were found in the unchallenged group (93), followed by the Yucca schidigera group (114), the anticoccidial group (243), and the challenged group (650). Adding Yucca schidigera abolished the effect of the challenge resulting in comparable (FCR) or better (ADG) performance results compared to the unchallenged birds. Yucca schidigera consistently showed lower numbers for OPG counts compared to the anticoccidial and challenged group. Therefore, Yucca schidigera can be considered as an effective alternative for anticoccidial treatment in broilers.
RESUMO
Bone is a dynamic tissue adapting to loading according to "Wolff's law of bone adaptation." During very early life, however, such a mechanism may not be adequate enough to adapt to the dramatic change in environmental challenges in precocial species. Their neonates are required to stand and walk within hours after birth, in contrast to altricial animals that have much more time to adapt from the intrauterine environment to the outside world. In this study, trabecular bone parameters of the talus and sagittal ridge of the tibia from stillborn but full-term precocials (calves and foals) were analyzed by micro-CT imaging in order to identify possible anticipatory mechanisms to loading. Calculated average bone volume fraction in the Shetland pony (49-74%) was significantly higher compared to Warmblood foals (28-51%). Bovine trabecular bone was characterized by a low average bone volume fraction (22-28%), however, more directional anisotropy was found. It is concluded that anticipatory strategies in skeletal development exist in precocial species, which differ per species and are most likely related to anatomical differences in joint geometry and related loading patterns. The underlying regulatory mechanisms are still unknown, but they may be based on a genetic blueprint for the development of bone. More knowledge, both about a possible blueprint and its regulation, will be helpful in understanding developmental bone and joint diseases. J. Morphol. 277:948-956, 2016. © 2016 Wiley Periodicals, Inc.
