Effect of Season on the Reproductive Organs of the Female African Giant Rat (Cricetomys gambianus) in Zaria, Nigeria

Abstract

SUMMARY:The study was carried out to determine the effect of season on the female reproductive organs of the African Giant rat using the standard methods, with the aim of obtaining the base-line values. The weights of the oviduct/uterus, vagina and the entire tubular organ were consistently higher during the harmattan season (0.789 ± 0.07 g, 2.708 ± 0.19 g and 3.455 ± 0.25 g, respectively) than the hot -dry (0.591 ± 0.02 g, 2.239 ± 0.13 g and 2.831 ± 0.14 g, respectively) and the rainy season (0.723 ± 0.04 g, 2.412 ± 0.01 g and 3.148 ± 0.12 g, respectively). The mean weight and length of the ovary were not significantly different throughout the season, suggesting that the AGR may breed throughout the year. The slight increase in the weight of the tubular organ during the harmattan (NovemberFebruary) and the rainy (June -October) season suggests that the seasons may be favourable for breeding, probably because of the abundance of food available to the rodents in the wild during the seasons. The decrease in weights of the organs during the hot-dry season (March -May) was, apparently, due to the unfavourable climatic conditions and food scarcity during the season. In conclusion, the results of the present study provide base -line morphometric data on the female reproductive organs of the AGR across the seasons.

Dimensional sex differences in the cerebellum of the African giant pouched rat (Cricetomys gambianus – waterhouse, 1840)

“…The aspects of biology which have received attention by researchers in AGR in recent times among others include the skeletal (Olude et al, 2010;Salami et al, 2011), digestive (Ali et al, 2008;Byanet et al, 2010) and reproductive (Ali et al, 2011) systems. Furthermore, sexual dimorphism has been reported in the body conformation and encephalization quotient (EQ) of AGRs; where females were observed to be larger (Byanet et al, 2009) and having higher EQ (Byanet and Dzenda, 2014) than males.…”

Comparación de la morfología geométrica de la mandíbula de dos roedores africanos, Thryonomys swinderianus y Cricetomys gambianus (Rodentia: Thryonomyidae y Nesomyidae)

“…In comparing diet in these rodents, other authors (Ajayi, 1977;Ali et al, 2011) reported that the African Giant rat survives more on domestic waste and less fiber diet, this is perhaps corroborated by its curved and longer mandibular architecture (longer buccinators muscle attachment), for food stowaway in cheeks, while T. swinderianus utilizes high roughage and fiber content plant food such as Austrophia species (spear grass), Pennisetum purpureum (elephant grass) and Saccharum species (sugar cane). This fact is postulated to contribute to the characteristics of some mandible anatomic parameters and becomes important in formulation of captive animal diet.…”

“…Fatalities resulting from brief occasional interactions between and within both species favour cane rats often by means of such differences. Numerical increases in the presence of such adults are precursors of new colonies and relocation of C. gambianus species (Matina et al, 2010;Ali et al, 2011).…”

Effect of Age at Breeding on Female African Giant Rat (Cricetomys gambianus) Fertility in Captivity

“…The age at puberty in FAGR was previously reported as 7.5 months (Tchoumboue et al 2002). Others research workers recently reported the age at puberty as varying from 4 to 5 months (Ali et al 2011). The higher PCCT and number of sexual cycles during cohabitation observed in 6-month-old rat could be due to their young age and perhaps, the puberty is not yet achieved, although in FAGR puberty onset is around 4 to 5.…”