I have installed some anti-viruses on my device, and since then I am feeling that the performance of the device is quite slow, and when I uninstall them the device works fine, and the device starts heating so quickely. So is this because of Apps from the Market or this issue is with my device.
Running Antivirus on Windows Phone is currently unnecessary and is unlikely to provide much protection should a virus appear in the future.
I am not aware of any Antivirus applications for Windows Phone that actually do anything. Should such an application exist, then by definition it will consume system resources and impact performance to some degree as it needs to monitor the device for viruses. Since you haven't listed the applications that you have installed it is impossible to gauge the performance impact.