Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) says that on the day of Khaybar the Messenger of Allah (peace and blessings be upon him) forbade "temporary marriage (mut'ah) with women and the meat of domestic donkeys."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19450