Tetsuya Matsuoka

Changes in blood parameters in New Zealand White rabbits during pregnancy.

Changes in clinical pathology parameters, particularly those related to blood coagulation, were examined throughout the gestation period in New Zealand White rabbits. As compared with the non-pregnant group, the following major changes were observed in the pregnant group. For blood coagulation-related parameters, platelets increased progressively and fibrinogen increased slightly from organogenesis, prothrombin time was significantly prolonged during organogenesis and shortened in the late fetal growth stage, activated partial thromboplastin time was significantly prolonged during the fetal growth stage, and antithrombin III increased during and after late organogenesis. Such changes in blood coagulation-related parameters during the later stages of gestation seem to be physiological responses in preparation for protecting against excessive haemorrhage or haemostasis at parturition. For the other haematological and blood chemical parameters as well as progesterone, red blood cell counts, haemoglobin and haematocrit began to decrease during organogenesis and continued to decrease thereafter. Reticulocyte counts significantly increased during organogenesis and decreased thereafter. White blood cell parameters, except for neutrophils, showed significant decreases during the fetal growth stage. Serum progesterone concentration reached its highest level early in organogenesis and decreased thereafter. Total protein, albumin, glucose, cholesterol, calcium, blood urea nitrogen and creatinine decreased significantly during the middle and/or late periods of gestation. In conclusion, the data obtained from the present study can be used as background data for effective evaluation of reproductive toxicology in rabbits, and pregnant rabbits may serve as models of pregnant women in research pertaining to clinical pathology and gestation.

Gastric hairballs in rabbits: significance in developmental toxicity study.

We surveyed 1053 pregnant rabbits of the Kbl:NZW strain collected from 27 developmental toxicity studies to reveal the prevalence and significance of gastric hairballs. The incidence of hairballs was 2/525 (0.4%) in the control group and 17/528 (3.2%) in the high dose group. In the high dose group, 16 dams resulted in abortion or death. In addition, decreases in body weight and food consumption were more severe in dams with hairballs than in their group‐mates without hairballs.

Characteristics of Kbl:Dutch rabbits in prenatal development in comparison with Kbl:New Zealand white rabbits

ABSTRACT  Prenatal development of Kbl:Dutch rabbits was studied in comparison with Kbl:New Zealand white rabbits. Significantly accelerated ossification of the 5th and 6th sternebrae and a low incidence of fetuses with a 13th rib were characteristic features in the prenatal development of Kbl:Dutch rabbits in comparison with Kbl:New Zealand white rabbits. These characteristics were largely consistent with earlier studies of Dutch rabbits from different suppliers and are notable when Kbl:Dutch rabbits are used for the evaluation of skeletal ossification.