Effects of Various Fat Sources Added into the Diets of Laying Hens on Calcium and Phosphorus Metabolism

This research was conducted to determine the effects of different vegetable oils and animal fat added into laying hens' rations at different levels during the late laying period on serum calcium and phosphorus levels. A total of 54 sixty-seven weeks old Isa Brown hens were weighed and randomly distributed into nine dietary treatment groups as C (control fed with only basal diet), T2 (basal diet + 2% tallow), M2 basal diet + 2% tallow and linseed oil mixture (50/50), S2 (basal diet + 2% sunflower oil), L2 (basal diet + 2% linseed oil), T4 (basal diet + 4% tallow), M4 basal diet + 4% tallow and linseed oil mixture (50/50), S4 (basal diet + 4% sunflower oil) and L4 (basal diet + 4% linseed oil), respectively. Each treatment group consisted of 6 subgroups, comprising of 1 bird each. At the end of the study, serum calcium and phosphorus levels (mg/dl) of C T2, M2, S2, L2, T4, M4, S4, L4 groups were 18.63 and 5.85, 18.03 and 4.52, 18.60 and 5.00, 16.62 and 4.42, 17.55 and 4.33, 16.25 and 5.63, 17.48 and 3.95, 17.47 and 3.28, and 21.43 and 5.12, respectively. The highest calcium level was observed in L4 group (21.43 mg/dl), while the highest phosphorus level (5.85 mg/dl) was detected in the control (C) group. As a result of the research, no significant effect (p>0.05) was found in terms of different fat sources and levels among the groups during the late laying period on the serum calcium and phosphorus levels of laying hens.