The Hinai-dori is a breed of chicken native to the Akita Prefecture in northern Honshu, Japan. A cross between the Hinai-dori and Rhode Island Red breeds has been commercialized as the Hinai-jidori chicken, and is one of the most popular brands in Japan. The meat of the Hinai-jidori chicken is considered much more palatable than that of typical broilers. To identify the candidate substances influencing the palatability of chicken meat, quantitative analyses were performed on the general biochemical components, free amino acids, inosine 5'-monophosphate (IMP), and fatty acids in the thigh meat of Hinai-jidori and broiler chickens. Hinai-jidori chickens and broilers were fed the same diet for 8 and 22 wk and were reared under the same conditions. The levels of free amino acids and glutamic acid in the meat of 8-wk-old broilers were significantly higher than those of 22-wk-old Hinai-jidori chickens. In addition, the IMP levels in 22-wk-old Hinai-jidori chickens were significantly higher than those of 8-wk-old broilers, whereas no significant difference in IMP levels was observed between 22-wk-old Hinai- jidori chickens and broilers. These data suggest that IMP content reflects a difference in the ages (weeks) of the chickens rather than a difference between the strains. However, a significant difference in arachidonic acid content was observed between Hinai-jidori chickens and broilers, suggesting that the high arachidonic acid content is a characteristic feature of Hinai-jidori chicken meat. Further studies are needed to elucidate the relationship between arachidonic acid content and the palatability of Hinai-jidori chicken meat.
