[Dick1038 (OP)]

There have been speculations as to what happened to the antimatter created during the BB.  It was suggested that there was a slight abundance of matter over antimatter and that the antimatter was annihilated when it collided with matter.  The slight overabundance of matter is the current universe. 

Well, the annihilation process produces gamma ray photons.  These photons should still be wandering around the universe but stretched out by expansion.  So, besides the MBR, there should be remnant gamma ray radiation.  Has anyone proposed searching for this radiation?

[Soul Surfer]

It has been stretched out so much that it is now no longer gamma rays but part of the cosmic microwave background radiation which is in fact quite bright.  It has been suggested that if we could see it in comparason to other sources it's about as bright as bright moonlight.

[graham.d]

This is a current theory, Dick. I think the cancellation happened very early in the expansion. The hot fireball of plasma that causes the MBR was not thought to be transparent until about 379,000 years after the BB which is the source of the Black body radiation which is the source of the MBR. There would have been huge amounts of scattering, absorption and radiation of all em radiation prior to this meaning that most individual spectral lines, including gamma rays, would have ended up being part of the smooth BB radiation curve.