Baryon density in alternative BBN models

We present recent determinations of the cosmological baryon density $\rho_b$, extracted from different kinds of observational data. The baryon density range is not very wide and is usually interpreted as an indication for consistency. It is interesting to note that all other determinations give higher baryon density than the standard big bang nucleosynthesis (BBN) model. The differences of the $\rho_b$ values from the BBN predicted one (the most precise today) may be due to the statistical and systematic errors in observations. However, they may be an indication of new physics. Hence, it is interesting to study alternative BBN models, and the possibility to resolve the discrepancies. We discuss alternative cosmological scenarios: a BBN model with decaying particles ($m \sim$ MeV, $\tau \sim$ sec) and BBN with electron-sterile neutrino oscillations, which permit to relax BBN constraints on the baryon content of the Universe.