Frequency of congenital abnormalities and of anatomical variations among JAX rabbits

Abstract

The frequency of congenital abnormalities and anatomical variations as observed among JAX rabbits is reported. Data were drawn from 32,082 inbred and partially inbred rabbits and 3,208 hybrids from the colony of the Jackson Laboratory over an eight-year period. Data reported here include stillbirths, rabbits dying from natural causes, and those killed for specific experimental regimens. Frequency data are based on the number of abnormalities observed in each category as a function of the total number of animals necropsied. This is approximately 95% of the animals born during the eight-year period and gives the frequency of abnormalities within each category rather than the number of individuals with one or more abnormalities. Anatomical variations have been found in almost all organ systems of JAX rabbits. Their presence adds to our knowledge of the characteristics of these strains, a knowledge that is critical to the understanding of the results of experimental manipulation or for determination of the presence of new mutations. There is considerable between-strain variation. Where frequencies are relatively high, the conditions are either known or suspected to be of genetic origin. Most of the anomalies are not deleterious, or their frequency is so low as to cause no problems within the colony. Hybrid populations have substantially fewer anomalies than do the parental strains. Where frequency is relatively high, it tends to be intermediate between the parental strains.

Morphological Abnormalities in Experimental Teratology: Need for a Standardization of the Current Terminology

“…In the absence of malformations, different biological meanings are attributed to the less severe alterations (the so-called minor anomalies, or minor changes, deviations, variations): these alterations do not evidence teratogenicity (Khera, 1974;Hudak and Ungvary, 1978); they are indicators of teratogenicity (Kim-me1 and Wilson, 1975;Imahori, 1975;Crary and Fox, 1980); they indicate some embryotoxicity or some secondary effect of maternal toxicity or stress (Yasuda and Maeda, 1972;Khera, 1984Khera, , 1987Beyer and Chernoff, 1986). The so-called retardations or developmental delays too are a subject of disagreement among teratologists.…”

Spontaneous Malformations in JW-NIBS Rabbits

“…4) and vertebral artery, and abnormal origin of the left common carotid artery. The frequency of spontaneous abnormal origin of the right subclavian artery is reported to be about 12-14% in JW-NIBS [10] and 13-15% in strains AX/J and AXBU/J [1]. Thus, this anomaly showed a lower frequency than reported in other breeds in our laboratories.…”

Anomalous branching of the aortic arch in a dog

“…In humans, the most common anomalies encountered in the vessels originating from the aortic arch involve the branching of the right subclavian and common carotid arteries (Natsis et al., 2009). In veterinary medicine, there are several descriptions of such anomalies in the dog (Bezuidenhout, 1989; Nam et al., 2003; Vitums, 1962), goat (Yilmaz and Arican, 2009), rabbit (Crary and Fox, 1980; Crary & Fox, 1980; Di Girolamo et al., 2018; Nakata et al., 2018) and pig (Hsu & Du, 1982).…”