Champions Cup holders Saracens will face Clermont Auvergne, Ospreys and Northampton Saints in next season's pool stages.
Treviso booked their place in next season’s Champions Cup as they defeated Zebre 19-3 on Saturday.
Gareth Anscombe scored 20 points as Cardiff Blues recorded an unconvincing
30-24 victory over Zebre at the Arms Park.
Glasgow's second string maintained the club's 100 per cent record against Zebre with a comfortable 45-10 win.
Zebre climbed off the bottom of the Guinness PRO12 table by beating Newport Gwent Dragons 29-14 in Parma.
Zebre claimed their first Guinness PRO12 home win of the season with a 25-22 victory over reigning champions Connacht.
Ronan O'Mahony touched down twice as Munster strengthened their grip on a top-four spot with a 50-14 victory over Zebre.
Ulster racked up their fifth successive win by thrashing Zebre 68-21 to move up to fourth in the Guinness PRO12.
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