Abstract

Objective: African giant rats (AGRs) host several zoonotic parasites, including Ascaris sp. The biological control of parasites in domestic animals includes the use of light manipulation. This study aimed to show whether light exposure affects growth parameters and susceptibility of male AGRs to Ascaris sp.
Material and Methods: Twenty male AGRs weighing 945 ± 171 gm were randomly assigned to four light schedules (light/dark; 0L:24D; 12L:12D; 18L:6D; 24L:0D). Dewormed, they were housed individually and had permanent access to food and water throughout the experiment (56 days). Weekly growth parameters (feed intake, daily weight gain, and live body weight) were collected, while Ascaris sp. eggs were analyzed biweekly in the fecal matter.
Results: Findings revealed that male AGRs' growth parameters were not significant (p > 0.05) among treatments. However, reduced photoperiod showed an upward trend, with the highest values recorded in animals enlightened 12 h per day. Two weeks after deworming, animals exposed to extended photoperiods had considerably (p < 0.05) more Ascaris sp. eggs than other animals. Meanwhile, Ascaris sp. egg abundance has gradually declined and, at the end of the trial, reached zero in certain treatments (0L:24D; 12L:12D; 18L:6D).
Conclusion: Light exposure does not affect growth performances, but AGRs reared under extended photoperiod are more susceptible to re-infection by Ascaris sp. after efficient deworming. The ideal light schedule for AGR husbandry is the natural photoperiod (12L:12D).

Key words: Cricetomys gambianus; growth parameters; parasite; photoperiod; Ascaris sp.