IOSR Journal of Agriculture and Veterinary Science (IOSR-JAVS) e-ISSN: 2319-2380, p-ISSN: 2319-2372. Volume 13, Issue 9 Ser. III (September 2020), PP 62-66 www.iosrjournals.org DOI: 10.9790/2380-1309036266 www.iosrjournals.org 62 | Page Effects of photoperiod on male African giant rat (Cricetomysgambianus) reproductive parameters in captivity Kenfack Augustave 1 , FonouTadiesse Lavoisier 1 , MweugangNgouopo Nathalie 2 , Atsamo Albert Donatien 3 ; TakamMbogne Boris 1 , FodaFopa Constant 1 , Sevérin Fonkem 1 , Tsambou Martine Astride 1 1 : Department of Animal Science, Faculty of Agronomy and Agricultural Science, University of Dschang PO Box 188 Dschang- Cameroon. 2 : Faculty of Sciences, University of Ngaoundéré, Ngaoundéré-Cameroon 3 : Department of Animal Biology and physiology, Faculty of Sciences, University of Yaoundé I, Yaoundé- Cameroon Abstract: Background: In captivity, African giant rat (AGR) is usually reared under a different photoperiod than in its natural habitat. Therefore, the aim of this study was to assess the effects of photoperiod on male AGR reproduction. Materials and Methods: For this purpose, twenty rats weighing 945 ± 171g were divided into four lots. Each lot was randomly allocated one of the following lighting times: 0h; 12h; 18h or 24h per day. The essay lasted 8 weeks. Results: The main results showed that the weight of testes and vas deferens were significantly (p<0.05) higher in male AGR subjected to less than 18 hours of light per day. Regarding the caudal epididymal sperm count, a similar trend, i.e. a gradual increase was observed with decreasing photoperiod, although without any significant difference (P>0.05). On the other hand, the reduction in the duration of exposure to light did not significantly affect (p>0.05) the serum testosterone concentration and the reaction time of the male to the presence of a female. Conclusion: A 12-hour photoperiod is not detrimental to male AGR fertility. Key Word: African giant rat, male, fertility, Photoperiod, captivity. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 20-09-2020 Date of Acceptance: 05-10-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Populations of sub-Sahelian countries have a fairly diverse wildlife animal that can be used as meat. 1,2 However, in view of population growth and the pressure exerted on wildlife, several species of rodents could disappear, if nothing is done urgently. 3, 4 This is the case of the African giant rat (AGR) 5 , also called cricetoma (Cricetomysgambianus). In fact, the quantities taken by hunting decrease year after year, reflecting its rarity in the wild.The breeding of AGR appears to be a solution for its preservation in the wild and therefore for a sustainable supply of its meat. Cricetoma farms have existed for several years and do not give satisfactory results when their performances are compared to those in the wild. The success of AGR production in captivity requires a better definition of its breeding techniques, taking inspiration from its way of life in the wild (feeding, reproduction and housing). Particular attention should be paid to the duration of exposure to light. Indeed, AGR lives in burrows and other dark dwellings during the day and only comes out at night. It is a nocturnal animal. 6, 7 In captivity, it is reared in lighted buildings for up to twelve hours a day. Couldn’t this be the cause of their poor performances in captivity? Photoperiod plays an important role in endocrine function and then in reproduction of animals, both wild and domestic. 8 In short-day species, the low photoperiod increases the synthesis and secretion of reproductive hormones including GnRH (gonadotropin-releasing hormone), FSH (follicle-stimulating hormone) and LH (luteinizing hormone). 9, 10 In Sprague-Dawley rat, Olayaki et al. 11 observed that lowering the photoperiod reduces testicular weight, sperm mobility, viability and count in the semen. On the other hand, Ali et al. 10 recorded a decrease in testicular weight and serum testosterone concentration in AGR continuously exposed to light. What would be the fertility of the male AGR if its environment in captivity was close to that in the wild? Else, could their poor performances in captivity be due to the too long photoperiod (12h/24) in livestock buildings? The aim of the present study was toanswer these questions, and the answers could be an important contribution to the success of cricetoma breeding in captivity.