Hormonal Changes, Immune Response and Date of Reentry in Laying Hens Fed by Alfalfa Molt Diet
2017
Shahrami, Ehsan | Rokni, Hasan
BACKROUND: The use of feed withdrawal method for molt induction can be caused physiological stress and negatively affected the immunological response of hens. OBJECTIVES: The aim of the present study was to survey of hormonal changes and immunological response in hens fed by alfalfa molt diet during the molt period. METHODS: In this experiment 108 Hy-line (W36) laying hens aged 74 weeks in a completely randomized design with 3 treatments and 6 replicates were used. The using treatments for 12 days molt period were included: 1- control group fed with layer ration (FF), 2- feed withdrawal group (FW), 3- group fed with 90% alfalfa and 10% layer ration (A90). Performance of birds was monitored for 12 weeks after the end of the molting period. RESULTS: Total circulating leukocyte were generally lower in FW hens group compared with the other groups during the initial stage of molt (P<0.05). On d 3 and 6 of molt, heterophil to lymphocyte ratio were incresed in molted hens and FW hens had higher levels than other groups. On d 3 of molt, plasma corticosterone was generally incresed in molted hens and FW hen higher level than A90 hens (P<0.05). Plasma T3 was significantly decreased in molted hens than nonmolted hens during the molt period (P<0.05). Plasma T4 was significantly increased in molted hens than nonmolted hens during the molt period (P<0.05). On d 6 and 9 of molt, concentrations of T4 were higher in FW hens than in the A90 hens (P<0.05). Date of reentry and days return to 50% and 80% egg production were significantly lower in A90 groups than in the FW groups (P<0.05). CONCLUSIONS: The results showed that, A90 diet can limit physiological stress and improve the performance of immunological response that accompany feed withdrawal method during an induced molt.
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