| Abstrakt: |
Investigations were undertaken to study the possible role of oviducal carbonic anhydrase during egg shell formation in 108 layers of Babcock-300 strain of three age groups of 21-24, 32-36 and 68-72 week old during spring and summer. Eighteen layers of each age group were subgrouped in three cyclic positions just after oviposition, 4 and 18 hours after oviposition. The distribution of carbonic anhydrase was significantly (P less than 0.01) higher in shell gland and low in isthmus in all the three age groups during both seasons. Carbonic anhydrase decreased (P less than 0.01) in summer in all three age groups. It was significantly (P less than 0.01) higher in magnum at the 14th h after oviposition in all the three age groups in both seasons, which established a new pattern of activity. Decreased concentration of the enzyme during the thermal stress period might be one of the factors responsible for the thinness of egg shell and for the increase in the number of soft shelled eggs. |
