MORPHOLOGICAL CHANGES AND PRODUCTION OF EGGS FROM COMMERCIAL LAYING HENS SUBJECTED TO ALTERNATIVE METHODS OF FORCED MOLTING

Abstract

In order to evaluate the effects of alternative methods of forced molting on morphological changes and production performance of commercial laying hens were used 488 Isa Brown birds line with 80 weeks of age. At the beginning of the experiment eight birds were slaughtered to determine the weight of the viscera, the remaining birds were distributed in an experimental design in randomized blocks with 6 treatments with 10 replicates of 8 birds per plot. The experimental period comprised the period of forced molting, lasting 28 days, and evaluated the performance, variation in body weight and organ (ovary and oviduct), levels of calcium and phosphorus contained in the ashes of metatarsus. The treatments were: T1: diet with restriction of production of calcium and phosphorus, T2: diet with restriction of production of calcium, phosphorus and sodium, T3: diet with restriction of production of calcium, phosphorus, sodium, methionine and lysine, T4: supply of corn, T5: conventional forced molting with 14 days fasting followed by production diet feeding until 28 days and T6: a control group that received feed production. During the molting period (28 days) all treatments received water ad libitum and were deprived of artificial light. Treatment subject to change conventional promoted greater loss of body weight and greater regression of the reproductive tract of birds, the only treatment being stopped temporarily to posture. The restriction of calcium and phosphorus did not affect the levels of these minerals in the metatarsus. The method of change did not affect the percentage of stance, percentage of broken eggs and mortality over the 28 days of experimental period.