Résumé:
This work has allowed us to demonstrate that the geometric MG morphometry can be
practiced to answer our questions, it is a powerful tool allowing to identify and visualize
the changes of the conformations of the beaks.
Modern techniques of morphometry are based on the configuration of landmarks or
landmarks that we have employed in a 2D frame; via the procruste overlay on scanned
images of the upper side nozzles, which allowed us to synthesize, at the desired
precisionpy scale, the geometry of an object. geometric morphometry has an exact and
rigorous mathematical foundation that guarantees robust statistics.
The objective is therefore to study and quantify the variability in beak shapes
(conformations + centroid sizes) of the 2 genotypes of normal local chicken and local bare
neck chicken, a total of 61 local normal chickens and 20 local bare neck chickens.
Principal component analysis (PCA) allowed us to extract 4 significant principal
components explaining about 85% of the total variation in the shape of the beak, hence the
permutation test, the Mahalanobis distance and that of procruste demonstrated a very
significant difference (P 0,0001) between the two strains ˂ naked neck and normally
feathered by the shape of the beak.
Therefore the landmarks method applied here via procrustean analysis has been shown to
be extremely efficient and accurate in identifying and visualizing beak conformations in
chickens.
Finally, we can say that our results reveal the great interest of MG in the study, on the one
hand, we have confirmed the hypothesis of the variability between the beaks of the two
strains, and on the other hand, it has us encouraged to continue studying to find a radical
solution to the problem at hand.
