Background: The effect of vitamin E and Selenium supplementation in diet of broiler chicken on growth performance and Heat shock protein70 (HSP70) level under summer heat stress was studied. Methods: The current study was conducted on 240 day-old commercial broiler chicks, which were divided randomly into four treatment groups of 60 numbers, with three replicates of 20 in each group. The control (T0) group was allotted with basal diet, group T1 (basal diet + Vitamin E @ 100 mg/kg and Selenium @ 0.2 mg/kg), T2 (basal diet + Vitamin E @ 125 mg/kg and Selenium @ 0.25 mg/kg) and T3 (basal diet + Vitamin E @ 150 mg/kg and Selenium @ 0.3 mg/kg). Result: In the present study, it has been found that, vitamin E and selenium supplementation in the diet of heat stressed broilers influenced the body weight (P=0.002), Body weight gain (P=0.001), Feed Intake (P=0.311) and BPEI (P=0.013) but not the Feed conversion ratio. Dietary vitamin E and Selenium supplementation increased the dressing percentage (P less than 0.001), Breast meat yield percentage (P=0.004), Thigh yield percentage (P=0.018), Drum stick yield percentage (P=0.013) and decreased abdominal fat percentage (P=0.004) under heat stress. The Heat shock protein level was improved (P less than 0.001) by dietary supplementation of vitamin E and Selenium under heat stress. The study indicated that growth performance, carcass characteristics and HSP70 level could be improved by dietary vitamin E and Selenium supplementation under heat stress.

Newcastle disease (ND) is a highly contagious viral disease of poultry causing significant economic losses worldwide. Vaccination is considered the most reliable approach to curb the economic menace that is ND, but the thermolabile nature of Newcastle disease virus (NDV) vaccination poses a significant threat to its protective efficacy. This study aimed to profile the thermostability of NDV isolates from duck (As/Km/19/44) and parrot (As/WB/19/91) and evaluate their immunogenic potential in chicks. Fusion protein cleavage site (FPCS) and phylogenetic analysis demonstrated the lentogenic nature of both the isolates/strains and classified them as class II genotype II NDV. The characterized NDV isolates were adapted in specific-pathogen-free (SPF) chicks by serially passaging. Biological pathogenicity assessment of chicken-adapted As/Km/19/44 (PSD44C) and As/WB/19/91 (PSP91C) revealed both the isolates to be avirulent with a mean death time (MDT) of more than 90 h and an intracerebral pathogenicity index (ICPI) ranging from 0.2 to 0.4. Both of the NDV isolates displayed varied thermostability profiles. PSD44C was the most thermostable strain as compared to PSP91C and the commercially available LaSota vaccine strain. The immunogenicity of PSD44C and LaSota was significantly higher than PSP91C. Based on these results, it is concluded that NDV isolate PSD44C is more thermostable and immunogenic when administered intraocularly without any adverse effects. Therefore, PSD44C is suitable for further research and vaccine development.