Sexual Maturation in the Female Göttingen Minipig

Abstract

In the literature, experimental data on sexual maturation of female Gö ttingen minipigs are lacking. This may impede a reliable evaluation of reproductive functioning, particularly in the young (immature) sow used in toxicity studies. To find suitable method(s) to detect ovulation during in-life, a pilot study was performed with 3 adult sows (approximately 10-11 months), followed by a study with 14 immature females (approximately 3-4 months). From the tested parameters, progesterone analysis was the most reliable predictor. First progesterone peaks were observed in 13 sows at 3.7-4.2 or 5.5-6.5 months with a cycle length of 17-22 days. One sow did not show progesterone release until necropsy at 7 months of age. Histopathology of the reproductive organs confirmed sexual maturity for all sows, except the one without progesterone peak. In conclusion, the age range of sexual maturity of female Gö ttingen minipigs (3.7-6.5 months) is much wider than previously thought, and in-life progesterone analysis is a useful tool to determine sexual maturity of individual animals.

Miniature pig magnetic resonance spectroscopy model of normal adolescent brain development

“…We replicated several neurochemical and diffusion trends reported in humans including an age-related rise in FA, KA and PDI parameters, age-related decline in concentrations of MI, and significant relationship between diffusion and MRS measurements [38, 107–114, 126–129]. We also observed a significant decline in MM09, a compound, which has yet to be fully studied in terms of human development.…”

“…The miniature pigs’ brain volumes is similar to these of the medium-size non-human primates used in laboratory research (100cm 3 for rhesus monkeys and 140 cm 3 for baboons)[123, 124]. The large brain volume of miniature pigs allowed for MRS and DWI data to be collected using a human protocol [100, 125] and revealed brain development patterns analogous to humans [38, 107–114, 126–129]. The use of a standard MRI scanner allowed for greater translational potential compared with small laboratory rodents [115–122].…”

Miniature pig model of human adolescent brain white matter development

“…A longitudinal imaging protocol was used to assess changes in WM integrity during normal adolescent maturation in miniature pigs. The trends of WM DWI measurements were similar to these observed during the period of adolescence and young adulthood in humans (Kochunov et al, 2012; Grinberg et al, 2017; Howroyd et al, 2016; Peter et al, 2016). In addition to the rise in DTI-FA values, we observed significant changes in two DWI parameters that describe the non-Gaussian diffusion properties KA and PDI.…”

Normal Developmental and Estrous Cycle–dependent Histological Features of the Female Reproductive Organs in Microminipigs

“…In the present study, 1 of the 5 animals (20%) at 5 months of age and 2 of the 5 animals (40%) at 6 months of age showed the histological features of puberty, whereas the rest (70%) at 5 and 6 months of age were immature. Similar observations have been made in Göttingen minipigs: the onset of puberty was observed at 3.7 to 4.2 or 6.1 to 6.5 months of age when female minipigs were housed with a boar, and only 50% of the females showed evidence of puberty by 6.5 months of age when they were not housed with a boar (Tortereau, Howroyd, and Lorentsen 2013;Peter et al 2016). All the females in the present study were bred, raised, housed, fed, and introduced to boars (a few minutes every day) under the same conditions, so that the differential developmental responses to sexual maturation in these microminipigs are caused only by simple individual variation.…”