ABSTRACT
1. The effects of feeding diets containing various amounts of magnesium on plasma concentration of calcium and magnesium in the domestic hen were investigated. 2. Plasma concentrations of calcium and magnesium decreased during shell formation in all birds. 3. Plasma magnesium content and egg shell thickness were severely reduced in birds given diets containing either 207 or 132 mg Mg++/kg. 4. Using electron microscopy, a precise correlation was observed between the normal distributions of magnesium and organic material across the egg shell of the domestic hen.
Subject(s)
Chickens/physiology , Egg Shell/metabolism , Magnesium/physiology , Oviposition/physiology , Animals , Calcium/blood , Egg Shell/ultrastructure , Female , Magnesium/administration & dosage , Magnesium/blood , Magnesium Deficiency/physiopathology , Magnesium Deficiency/veterinary , Poultry Diseases/physiopathologySubject(s)
Meningitis/microbiology , Streptococcus/isolation & purification , Cerebrospinal Fluid/microbiology , Child , Deafness/etiology , Humans , Male , Meningitis/cerebrospinal fluid , Penicillin G/therapeutic use , Streptococcal Infections/cerebrospinal fluid , Streptococcal Infections/drug therapyABSTRACT
The eggshell of the domestic fowl has been studied by transmission electron microscopy and diffraction. Thin sections of shell were prepared by chemical and ion-beam thinning techniques. Each calcite column of the palisade layer consisted of crystallites of diameter 20 to 30 micrometer with some tendency for crystallite alignment within a single column. Evidence indicates that there was no significant preferred orientation in the palisade layer as a whole. Only in the surface layer was any preferred orientation detected, and here (1014) planes tended to lie parallel to the surface. The results are compared with previously published data, and calcite nucleation and growth are discussed.
