Selected chemical properties and ultrastructure of the egg shell in relation to resistance to shell failure of Philippine Mallard duck (Anas platyrynchus Linn.) eggs
1998
Manipol, N.E.P. | Roxas, N.P. (Philippines Univ. Los Banos, College, Laguna (Philippines). Inst. of Animal Science)
Egg shell thickness, percentages of calcium, phosphorus and total protein content of the shell membrane of intact and cracked Philippine Mallard duck eggs at different incubation periods (day 1, 9 and 18) were determined. The treatment design used was 3 x 2 factorial in complete randomized design with 3 replications. Mean comparison were done using the least significant difference (LSD) test. The ultrastructure of the egg shell was examined using a scanning electron microscope. The shell thickness varied significantly at different incubation periods considered (P less than 0.05). LSD test showed that shell thickness of the intact eggs at different incubation periods were significantly higher (P less than 0.05) than that obtained in cracked eggs. Shell thickness of intact eggs at 1st day of incubation period also differed significantly from the values obtained during the 9th and 18th day of incubation. Calcium contents of the shell were highly significant (P less than 0.01) at different incubation periods. Mean values significantly decreased as incubation period progressed. The phosphorus contents of intact and cracked eggs at different incubation periods considered were however, not significantly different. Ultrastructural examination illustrated denser fibers and mammillary knobs, smoother mammillary knob surface, more uniform width of palisade layer, thicker surface crystal layer and cuticle completely covering the shell in intact eggs compared to those of the cracked eggs
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