a production of N$^{14}$, which originates primarily in the pregalactic stars, and subsequently in the galactic ones [@Bahena2006], as it will be shown in details in a forthcoming paper.

[@Meynet2002] and [@MaederMeynet2003] have shown that the stellar rotation and mass loss can affect the predictions of the stellar yields especially for He, C, N and O. At low $Z$, the rotation may be a dominant effect in massive star evolution. They estimate that low $Z$ stars may loose mass due to fast rotation as a consequence of their initial slow winds, and initial rotation velocities may be faster [@Maeder1999]. Their models of massive stars at low $Z$ do not reach in general the red stage. However, rotation permits the envelope to largely expand and the star moves to the red supergiant stage, modifying all the models outputs. Then, the rotation affects the evolution of very metal-poor massive stars [@Meynet2005] and can induce mass loss in many ways [@Meynet2006a]. The compactness of low metallicity stars is a key property which has many effects in relation with stellar rotation.

$$

[@cccccccccccc@]{}\
$M_{\rm i}$ & $N$ & $\tau_{\rm H}$ & $\Delta M_{\rm H}$ & $q_{\rm
cc, H}$ & $M_{\rm f, H}$ & $M_{\rm 