Marcin Wilk, 26, claimed that Polish and Bulgarian employees at the zoo on Öland island received lower wages and were ill-treated during his stint there in 2011.
He claimed that the zoo was run like an "old-fashioned feudal system," with a strict top-down structure.
In a recording of his dismissal, played up in court in December 2012, a manager is heard screaming at Wilk:
"You think you're better than others. Take your things and go to hell. You're behaving like a damn monkey."
Wilk claimed that he and other Poles worked 10-hour days without a weekend or time off while the zoo's Swedish staff worked a regular 40-hour week.
While Swedes were paid 14,000 kronor ($2,160) per month, the Polish workers got 6,800 kronor plus room and board, he said.
"I was discriminated on the basis of my nationality. But everyone who works with discrimination issues knows that it is hard to prove. Discrimination is hidden," Wilk told the Barometern newspaper.
Wilk was asking for 1 million kronor in damages, but now that the district court has ruled that the alleged crimes had passed the statute of limitation, he will be obliged to pay the zoo's legal bills.