Indigenous Okinawa Agu pigs were once widely raised in Okinawa, Japan. Numbers of this breed reached 104,321 in 1899 (Touma, Arakawa, & Oikawa, 2020), but with the introduction of European pig breeds in the early 1900s, Agu pigs were gradually replaced by foreign breeds, and even faced imminent extinction in the 1980s. Due to a conservation program that was started in 1981, populations of Agu pigs have recovered and the pork from this breed (Agu pork) is known for its good taste. In our assessments of meat quality, Agu pigs had high intramuscular fat contents (IMF), high juiciness, and high monounsaturated fatty acid (MUFA) and low polyunsaturated fatty acid (PUFA) levels (Touma, Onaga, Toubaru, & Oikawa, 2017). Recently, demand for Agu pork has increased with the growing desire among consumers and pork producers for specialty and value-added pork. As shown for other indigenous breeds, Agu pigs growth performances and lean meat productivity are low (Touma et al., 2017). Moreover, Agu pigs have poor fertility, with small litter sizes (total number born, 4.8) (Touma & Oikawa, 2017) and low conception rates (Yamauchi et al., 2009), likely reflecting inbreeding (Touma et al., 2020). Thus, it is difficult to secure a stable supply of Agu pork. Generally, indigenous breeds have low growth and meat production, but have good meat qualities (