The effect of different methods of force molting on immune response, some biochemical parameters and reproductive traits of layers

    This experiment was conducted to evaluate the effects of differernt methods of forced molting on immune, changes of blood parameters and reproductive traits of laying hens. In this experiment, one hundred eighty 52-week- old Hy- Line layers with 6 treatments, 5 replicates and 6 birds per each were used in completely randomized design. Treatments were 1- feed withdrawal, 2- diet containing 50 percent alfalfa meal and 50 percent layer ration, 3- diet containing 75 percent of alfalfa meal and 25 percent layer ration, 4- diet containing 100 percent of alfalfa meal, 5- whole grain barley  and 6- deit containing high level of zinc (zinc at 20g/kg of diet). The results showed that triglyceride and HDL concentrations of birds that fed whole grain barley were higher compared to other treatments in 10 d (P<0.05). Also concentration of cholesterol and LDL in the treatment of barley whole grain, 75 and 100% alfalfa meal were lower than the other treatments. At day 10, 75% alfalfa: 25% layer ration group had highest and at day 28, zinc group had lowest antibody titers against SRBC (P<0.05). Different methods of force molting increased white follicles in birds fed 75% alfalfa meal significantly and decreased it in feed withdrawal group and birds fed 100%  alfalfa meal (P<0.05). The results of this experiment showed that use of 75% alfalfa meal and whole grain barley had beneficial effect on blood lipid parameters and antibody titers against SRBC during force molting of laying hens.