An experiment was conducted to evaluate egg quality and ultrastuctural measurements of eggshell using a Scanning Electron Microscope (SEM) in 2 lines (selected and control) of Japanese quail. A selection program was applied over 22 consecutive generations for higher egg production and lower broken egg percentage. The results revealed that the females of the selected line produced significantly (P < 0.01) higher egg mass compared to that of the control line. Also, the selection procedure significantly improved feed conversion ratio. The eggshells of the selected line had a higher breaking strength compared to those of the control line, although there was no difference between them in shell thickness. Significantly higher wet (P < 0.01) and dry (P < 0.05) eggshell percentages were found in the selected line. In general, the eggshells of the selected line had a lower total score (good) of ultrastructural evaluation compared to the control line. According to scanning electron microscope data, the incidence of certain structural variants was more common in eggshells of the control line suggesting poor shell strength. The incidence of alignment was more prevalent in control eggshells compared to selected ones, suggesting lower resistance to breakage. Late fusion and large interstitial spaces of the palisade layer indicating decreased resistance to fracture were observed in control eggshells. It could be concluded that the improvement eggshell quality may be caused by the long-term selection for lower cracked and broken egg rates from generation to generation.

Scanning electron microscopy was used to assess the effect of selection on eggshell ultra structure in Alexandria chicken. The observed changes were studied to understand the role of selection in eggshell strength. There was a significant difference for egg and eggshell weights between lines. Concerning shell breaking strength, selection improved the shell breaking strength (29.30 vs. 31.71 N). Indeed, toughness (380.9 vs. 411.9), stiffness (133.9 vs. 138.8) and elasticity (15592.3 vs. 15609.5) were improved in line selected compared control line. Scanning electron microscopy (SEM) analysis indicated that there was a significant increase in total, palisade and caps thickness in eggshell from the selected line compared to the control line. Confluence was significantly increased in the selected line than the control references, with better attachment between cone and shell membranes in the selection line. It can be concluded that the ultra structure of eggshell measurements and/or the associated genetic markers may therefore prove to be useful in selection programs to improve eggshell quality.

The objective of the following study was to determine the incidence of tibial dyschondroplasia (TD) among 4 crosses (crosses A, B, C, and D) of male meat-type commercial broilers and its relationship to gait score at 6 wk of age. At 38 and 39 d of age, 360 birds were evaluated individually for gait score. Three male chickens/pen with good walking ability (gait score of 0 or 1) and 3 male chickens/pen with poorer walking ability (gait score of 3) were killed and individual BW determined at 6 wk of age. Both drumsticks were retrieved and the distal and proximal tibia were scored for TD lesion (0 = no lesion; 1 = mild lesion; 2 = moderate lesion; and 3 = severe lesion). Data were analyzed via ANOVA using the mixed model procedure of SAS. Very few birds showed TD lesions. The TD scores were similar among crosses even though gait scores differed among genotypes with cross C having better gait scores than crosses A and B but did not differ from cross D. The TD lesion scores did not differ between male broilers with a gait score of 0 or 1 (mean TD lesion score of 0.03 ± 0.03) as compared with those with a poorer walking ability and a gait score of 3 (mean TD lesion score of 0.08 ± 0.03). The proximal end of the right and left tibia had similar TD lesion scores. The TD lesions scores were higher for the right proximal tibia when compared with the distal ends of the right and left tibia. These results suggest the poorer walking ability of male broilers in this study was not due to TD lesions.