Breeding seasons in animals are influenced by temperature, potentially leading to shifts in timing along latitudinal gradients. To accurately determine the breeding season, it is essential to collect data on reproduction across various regions. In early May 2024, we observed mating-related behaviours of the Japanese giant flying squirrel (Petaurista leucogenys) on Kyushu Island, the southernmost habitat of this species. The mating dates at this study site (32°49′N) were estimated to be from May 5 to 7, which is approximately one week earlier than results of 14-years observation in two populations (34°41′N -35°35′N) on Honshu. In order to investigate the relationship between the mating days of the flying squirrels and temperature in more detail, it is necessary to gather more information on mating in Kyushu, as well as those in habitats further north, such as the Tohoku region.

View full abstract

　We investigated the changes in alkaline phosphatase (ALP) isoenzyme patterns and activity in serum samples stored at ultra-low (−80℃) and standard (−20℃) freezing conditions over 18 months in six zoo-managed Asian elephants (Elephas maximus) in Japan. Serum total ALP activity decreased after 6 months at −20℃, but remained stable for up to 18 months at −80℃, except at 1 and 12 months. The relative proportion and activity of two ALP isoenzymes (ALP2 and ALP3) remained unchanged over the 18-month period at both temperatures. These findings suggest that frozen serum can be effectively used in future agarose gel electrophoresis analysis to evaluate ALP isoenzyme activity, provided that total ALP is measured immediately after blood collection.

View full abstract

　This study evaluated the effects of a gonadotropin-releasing hormone (GnRH) vaccine on the suppression of sexual aggressiveness in domestic quails (Coturnix japonica domestica), particularly male-to-male mounting behaviour. Six group-housed male quails were immunized with Improvac® by administering 0.1 mL/dose/individual given twice. The effects of the vaccine on mounting behaviour suppression were assessed by measuring feather loss at seven body spots using a three-level scoring system before and after administration. The total score profile of each individual remained consistent regardless of GnRH vaccine administration, indicating that the effect of immunocastration in domestic quails could not be confirmed. Further investigation is needed to optimize dosage, number and frequency in administration protocols.

View full abstract