This study was conducted to determine the effect of mussel (Unio Elangatus Eucirrus Bourguignat) shell supplementation as calcium source on feed intake, egg production, egg weight, feed efficiency and some blood parameters in heat-stressed layer Japanese quails. Three hundreds 9 week-old female Japanese quails (Coturnix coturnix japonica) were used as animal material. Each group consisted of 60 birds, three birds per cage. Calcium sources added in diets constituted the basis of the experimental groups. These groups were as follow: Control group with 100% limestone, A group with 75% limestone+25% mussel shall, B group with 50% limestone+50% mussel shall, C group with 25% limestone+75% mussel shall and D group with 100% mussel shall. Experiment was carried out for 90 days.

While the supplementation of mussel shell to the diets was improved egg production (p<0.05); feed intake, egg weight, feed efficiency ratio and mortality were not differed statistically (p>0.05). Plasma glucose, cholesterol, triglyceride, alanine transaminase, aspartate transaminase, sodium, potassium, and clor levels were similar in all groups. The highest plasma calcium (Ca) level was in C group (28.2 mg/dl) following this A group (25.8 mg/dl), D group (25.4 mg/dl), B group (25.3 mg/dl) and control group (23.5 mg/dl). The plasma magnesium level was increased to be parallel the increasing of mussel shall level.

In conclusion, the results show that, the mussel shell may be use by 75% as calcium source in quail diets in stead of limestone.