Effect of a Shell Gland Irritant on the Secretion Rate, Calcium and Inorganic Phosphorus Levels of the Shell Gland Fluid in the Laying Hen

Abstract

Changes in the secretion rate, calcium and inorganic phosphorus concentrations of the shell gland fluid during shell formation were determined in the hen which had a loop of thread in the shell gland and which continued to lay the soft-shelled eggs only (called treated hens). Determinations were also done in the normal laying hen as a control. The secretion rate of the shell gland fluid was lower in the treated hens than in the control. The calcium content in the shell gland fluid of the control was lowest at the first 5 hour stage of shell formation and increased during the active calcification stage. In the treated hens, calcium contents in the fluid were markedly different from those of the control at some stages of shell formation, the pattern of change, however, being similar to controls. Inorganic phosphorus level of the shell gland fluid in normal laying hens fluctuated significantly (P<0.05) during shell formation. The value was observed to be highest at the end of calcification and was lowest when active calcification was in progress. A remarkable phosphorus change in the fluid was also observed in the treated hens in relation to premature oviposition: the level of the fluid became higher just after the premature oviposition than that in the period during which the egg was staying in the shell gland. From these results, it is assumed that the presence of a loop of thread in the shell gland causes the low secretory activity of the shell gland and causes the abnormal composition of the shell gland fluid. The rapid increase of inorganic phosphorus content in the shell gland fluid in the hen with a shell gland irritant may be partly related to the inhibition of shell deposition, and to premature expulsion of the soft-shelled egg.It was demonstrated by several workers1, 2, 3, 4, 5, 6) that a loop of surgical thread placed through the wall of the shell gland resulted in the expulsion of soft-shelled eggs. The mechanisms for this, however, have not been explained up to date except the nervous system may be involved7).In our previous study on the hens with a thread in the shell gland, it was found that, shell weight almost never increased, even when the soft-shelled egg present in the shell gland was made to stay artificially for about 24 hours in it by tying loosely the upper part of the vagina, and that the presence of a loop of a thread in the shell gland wall seemed to bring about the abnormal crystallization of calcite on the shell membrane (unpublished). These results suggest the possibility that the production of the soft-shelled eggs in such treated hens may be partly induced by the inhibition of shell deposition mechanisms: low secretory activity of the shell gland and abnormality of the fluid composition in the shell gland.In normal hens, the secretion rate of the shell gland fluid was influenced by the physiological state of the gland with regard to egg formation8, 9), and calcium content of the fluid was also changed during shell calcification in chicken9, 10, 11) and turkey12) hens. On the ...

The Effect of Indomethacin on the Superficial Pigmentation of Japanese Quail Eggshell.

“…Similar results were reported in chicken (ITOH and HATANO, 1964;NYS et al, 1991) and the inorganic phosphorus concentration of the shell gland fluid increased close to oviposition (OGASAWARA et al, 1974;MURAKAMI and KOGA, 1991…”

Effects of phosphate, prostaglandins, arachidonic acid and arginine vasotocin on oviposition and pigment secretion from the shell gland in Japanese quail

“…In laying hens, too, there are large amounts of phosphorus in the outermost layer of egg shell (Itoh and Hatano, 1964;Nys et al, 1991); in addition, the inorganic phosphorus concentration of the shell gland fluid was either at its peak at the completion of calcification (Ogasawara et al, 1974) or it increased close to oviposition . An intrauterine injection with phosphate solution disturbed shell deposition (Ogasawara and Koga, 1977), induced an increase in the concentration of prostaglandin in the shell gland tissue, a release of arginine vasotocin from posterior pituitary, and premature oviposition (Klingensmith and Hester, 1983;Ogasawara et al, 1975;Ogasawara and Koga, 1978;.…”

Effects of an Induced Molt and Shell Quality on the Physical Dimensions and Mineral Composition of Eggs and Intrauterine pH ,

“…Uterine fluid inorganic phosphorus levels remain significantly lower than plasma inorganic phosphorus concentrations throughout the period of shell formation but increase sharply to equal the level in the plasma at oviposition (Ogasawara et al, 1974). The dramatic decline in serum phosphorus 2 to 3 hr prior to oviposition (Miller et al, 1977a,b) also may coincide with phosphorus transport from the blood to the shell in the uterus, again explaining the occurrence of higher phosphorus concentrations on the outermost vs. the innermost layer of the shell (Itoh and Hatano, 1964).…”