Hydrotreating hydrocarbon feeds in an ebullating bed reactor

In a process for hydrotreating a hydrocarbon feed, in contact with an ebullating bed of catalyst, the improvement wherein the catalyst comprises an essentially alumina-based extruded support, essentially constituted by a plurality of juxtaposed agglomerates, at least one metal selected from the group consisting of metals or compounds of metals from group VIB and metals or compounds of metals from group VIII, in which the sum S of the group VIB and VIII metals, expressed as the oxides, is in the range of 0.1% to 50% by weight, characterized in that each of said agglomerates is partly in the form of packs of flakes and partly in the form of needles, said needles being uniformly dispersed both about the packs of flakes and between the flakes, and in that the catalyst further comprises at least one dopant selected from the group formed by phosphorous, boron, silicon (or a silica which is not of the type which could be contained in the selected support) and halogens.