Calcium and phosphorus requirements of Japanese quail layers (Coturnia coturnix japonica)

Three studies were conducted to determine the biological response of Japanese quail layers to diets containing different levels of calcium and phosphorus. In study 1, a total of 540 (12 weeks old) Japanese quail layers were used to determine calcium (Cal) and phosphorus (available, Pav) requirements of the birds for early production period. The birds were randomly assigned to six treatments consisting of three levels of Ca (2.5, 3.0 and 3.5 percent) and two levels of Pav (0.25 and o.35 percent) following factorial completely randomized design. Each dietary treatment had three replication with 30 birds per replication. Quails in the early lay period attained optimal production, feed conversion ration, and egg mass on a diet containing 3.0 percent Ca with 0.25 percent Pav level; comparable production with this group was observed with birds fed on 3.5 percent Ca with 0.25 percent Pav. Quails on 3.5 percent Ca irrespective of Pav levels in the diet elicited higher tibia ash content. Eggshell weight was higher for diet with 3.5 percent Ca and 0.35 percent Pav than the diet containing 3.0 percent Ca and 0.25 percent Pav. In study 2.270 (42 weeks old) Japanese quail hens were used to determine Ca and Pav requirements of the birds for post-peak period. Optimal egg production was attained for quails in the post-peak production with 3.5 percent Ca, irrespective of Pav level: production of birds fed on a diet containing 2.5 Ca with 0.35 percent Pav was comparable with this group. The feed conversion ratio was superior in diet containing 3.5 percent Ca with 0.35 percent Pav which was a result of optimal egg production and low feed intake. Study 3 evaluated the performance of post-peak japanese quail layers fed diets with all oyster shell calcium supplement and monodicalcium phosphate as source of phosphorus. Quails in this post-peak period attained optimal egg production and feed conversion ratio when 2.5 percent Ca and 0.35 percent Pav was included in the diet. Quails on 3.5 percent Ca attained higher tibia ash content irrespective of Pav level in the diet. Overall, the findings in Studies 1, and 2 indicate that the requirement of Japanese quail layers for calcium is higher than the 2.5 percent currently practiced in feed formulation when equal amount of limestone and oyster shell is used in the diet. Such amount of dietary Ca (2.5 percent) is adequate when all oyster shell Ca supplement is used. A dietary Pav level of 0.35 percent in satisfactory for all periods, irrespective of Ca supplement.