Context : Quasars trace the most massive structures at high redshifts and their presence may influence the evolution of the massive host galaxies .

Aims : We study the extended Ly \alpha emission line regions ( EELRs ) around seven bright , mostly radio-quiet quasars ( QSOs ) at 2.7 < z < 4.5 , and compare luminosities with EELRs around radio-loud QSOs reported in the literature .

Methods : Using integral field spectroscopy , we analyse the morphology and kinematics of the quiescent Ly \alpha EELRs around the QSOs .

Results : We find evidence for the presence of EELRs around four radio-quiet and one radio-loud QSO .
All EELRs appear asymmetric and the optically brightest QSOs also have the brightest Ly \alpha nebulae .
For the two brightest nebulae we find velocities between \sim 600 km s ^ { -1 } at the QSO position to \sim 200 km s ^ { -1 } at a distance of 3 - 4 ″ from the QSO and surface flux densities up to 2–3 \times 10 ^ { -16 } erg cm ^ { -2 } s ^ { -1 } arcsec ^ { -2 } .
The five EELRs have total Ly \alpha luminosities which correspond to \sim 0.5 % of the luminosities from the QSOs broad Ly \alpha emission lines .
This fraction is an order of magnitude smaller than found for EELRs around radio-loud , steep spectrum QSOs reported in the literature .
While the nebulae luminosities are correlated with the QSO Ly \alpha luminosities , we find that nebulae luminosities are not correlated with the central QSO ionising fluxes .

Conclusions : The presence of gas in the EELRs can be interpreted based on two competing scenarios : either from quasar feedback mechanisms , or from infalling matter .
Apart from these two effects , the Ly \alpha flux around radio-loud objects can be enhanced due to interactions with the radio jets .
The relatively fainter nebulae around radio-quiet QSOs compared to lobe-dominated radio-loud QSOs can be ascribed to this effect , or to significant differences in the environments between the two classes .