A feed system for feeding lubricating oil to members of a turbine engine including a reduction gearbox, the feed system including a nonpositive-displacement pump device for connecting upstream to an oil tank and driven in rotation at a speed that is not correlated with an operating speed of the turbine engine; a separator node connected to the outlet of the nonpositive-displacement pump device; a first delivery branch for lubricating the RGB connected to the nonpositive-displacement pump device via the separator node; a second delivery branch for lubricating other members connected to the nonpositive-displacement pump device via the separator node, the second delivery branch including a positive-displacement pump; and at least one fluid metering device having a metering slot fed by the nonpositive-displacement pump device via the separator node for the purpose of feeding the RGB.