The Damped Ly- \alpha ( DLA ) absorber at redshift z _ { abs } = 4.383 observed toward QSO BRI 1202-0725 is studied by means of high resolution ( FWHM \approx 7 km s ^ { -1 } ) VLT-UVES spectra .
We refine a previously determined Si abundance and derive with confidence abundances for C , N and O which are poorly known in DLAs .
The [ O/Fe ] ratio is \sim 0.6 , but we can not establish if iron is partially locked into dust grains .
The [ C/Fe ] = 0.08 \pm 0.13 and [ Si/C ] = 0.31 \pm 0.07 .
[ N/O ] and [ N/Si ] are about -1 , which is consistent with the majority of DLAs .
This value is much larger than the one observed for the DLA toward QSO J 0307-4945 at z _ { abs } = 4.466 .
The current interpretation of the bimodal distribution of N abundances in DLAs implies that large [ N/ \alpha ] values correspond to relatively old systems .
Adopting a scale time of 500 Myrs for full N production by intermediate mass stars , the onset of star formation in our DLA took place already at redshift > 6 .