There are few data about early thermal conditioning (TC) and its effect on later life in rabbits. Therefore, the present study aimed to investigate the impact of exposing two rabbit breeds to early age short-term heat stress (EA-STHS) on physiological parameters and hepatic expression levels of some genes. Rabbits from New Zealand White (NZW) and Baladi Black (BB) rabbit breeds were reared in a controlled environmental chamber (28 ± 2
C and 40 ± 2% RH). At 42 days of age, rabbits from both breeds were equally divided into two groups; control (untreated) and heat exposed groups (kept at 36 ± 1
C and 62% RH for 6 h). At 13 weeks of age, rabbits of all groups were re-exposed to acute heat stress (36 ± 1
C and 62% RH for 6 h). At 13 weeks of age, plasma CORT, plasma MDA, and hepatic MDA had significantly lower levels in the rabbits from the two breeds subjected to EA-STHS than untreated control groups. plasma TAC and the relative hepatic expression of all the studied genes like Hsp70, HspA9, Hsp90a and UCP2 had significantly higher levels in EA-STHS treated NZW and BB rabbits compared with the control groups. In conclusion, the results suggest that EA-STHS has a long-lasting effect on the later life response to acute heat stress in NZW and BB breeds, as indicated by the hepatic expression profile of several genes, corticosterone, and antioxidant parameters. Additionally, each breed had characteristic patterns for the tested parameters at each time point and treatment.