Morphological Characterization of the African Giant Rat (Cricetomys gambianus, Waterhouse) Brain Across Age Groups: Gross Features of Cortices

This experiment was designed to investigate the morphological characterization of the brain cortices of African giant rats, AGR (Cricetomys gambianus, Waterhouse) across age groups as related to function. A total of 15 male AGR were used for this study comprising of 5 neonates, 5 juveniles and 5 adults. Brains were described as having typical rodent features; the falx cerebri, the dura modification of interest, was partly inserted between the lobes of the olfactory bulb and extended towards the corpus callosum. Gross parameters extrapolated include cerebral and cerebellar cortical dimensions using a one-way ANOVA (p≤0.05). Most values showed highest significant value bias for juveniles over adults and neonates. The average brain weight was 5.60±0.06g, 4.64±0.17g and 0.62±0.08g; cortex volume: 2.84±0.04cm3, 3.16±0.10cm3 and 0.23±0.02cm3 and antero-posterior dimensions: 11.93±0.26mm, 14.54±0.22mm and 6.00±0.16mm for adult, juvenile and neonates respectively. There was however adult bias in the cerebellum weight (0.83±0.02g, 0.76±0.02g and 0.04±0.02g); vermis length (13.23±0.32mm, 11.27±0.014mm and 0.24±0.02mm) and the antero-posterior length values (8.79±0.19mm, 6.97±0.03mm and 0.29±0.01mm) for adults, juveniles and neonates AGR respectively. Cortical parameters were related as a function of the brain development and plasticity, while age was described to play functional roles in intelligence determination of the AGR. The result of this study will be useful as baseline information for post mortem studies, medical imaging and useful as diagnostic tool for future research work on the AGR brain.Keywords: African giant rats, Brain, Morphology, Cerebrum, Cerebellum, Olfactory bul

Normal Aerobic Vaginal Bacterial Flora of The African Giant Rats (AGR) Captured from Their Natural Habitat in Abeokuta, Ogun State, Nigeria

The genital tract of female animals, especially the caudal region, is known to habour non specific bacteria that are sometimes called the normal bacterial flora. In this study, we examined 12 apparently healthy female African giant rats (Cricetomys gambianus, Waterhouse) (AGR) to determine their vaginal bacterial flora. Swab collected from the vagina of each rat after previous chloroform anaesthesia was seeded onto blood and MacConkey agar plates and incubated aerobically at 370C for up to 48hours. Isolates were then characterized using various character parameters. The results indicated that 7 bacterial genera inhabit the vagina of the 12 African giant rats that were studied. The distribution of the bacteria species in the AGR were highlighted in the text. It is inferred from the results that under stress condition, these bacteria could cause disease in the African giant rats

Protective Effect of Ethanol Extract of Annona Muricata Leaves on Hematological Profile, Histology and Oxidative Stress in 1,2-Dimethylhydrazine-induced Colorectal Carcinogenesis in Rats

Cancer starts when cells in the body start to grow out of control (malignant growth). Colorectal cancer starts in the colon or the rectum. Annona Muricata is a medicinal plant and is considered as a basis for health preservation and care worldwide. Colorectal cancer has reached epidemic proportions and is considered as a serious health problem, therefore treatment and cure of this disease is of great clinical importance. 1,2 dimethylhydrazine (DMH) is a potent carcinogen for colon cancer in rats. In this study, rats were randomly allocated into six groups: control, extract alone, DMH, extract and DMH together, extract before DMH, DMH before extract. DMH was injected subcutaneously at 25mg/1000g body weight once a week for 16 weeks, while the ethanol extract of Annona muricata leaves (EEAML) were administered to rats orally at 120mg/1000g. After sacrifice, colon and liver sections were dissected out for histological and some biochemical analysis. Blood was also collected in EDTA bottles for hematological assays. The group injected with DMH (subcutaneously) and orally administered leaves extract of A. Muricata simultaneously showed similar results with the rats fed with normal feed, as there was absence of polyps in the rats’ colon when compared with those injected with DMH alone for 16 weeks. Malondialdehyde level of rats injected with DMH were significantly increased (p ˂ 0.05) compared to the control. Hematology indices and caspase 3 activity show the protective effects of EEAML against DMH.

Actinomycosis in a West African Dwarf goat in Nigeria.

Actinomycosis, also called Lumpy jaw is a chronic, progressive, indurated, granulomatous, suppurative abscess that most frequently involves the mandible, the maxillae or other bony tissues in the head. It is a sporadic but common disease in cattle, occasional in pigs and horses and rarely in goats (Radostits et al., 2007). Members of the genus Actinomyces are Gram positive, non-acid fast, non-spore forming rods (Songer and Post, 2005) that form a mycelium of branching filaments that fragment into irregular-sized rods (Blood et al., 2007). The species that commonly cause disease in domestic animals include A. bovis, A. hordeovulneris, A. hyovaginalis, A. israelii, A. naeslundii, A. suis, A. viscosus and Arcanobacterium pyogenes (Songer and Post, 2005). Actinomyces bovis is a common inhabitant of the bovine mouth and infection is presumed to occur through wounds to the buccal mucosa caused by sharp pieces of feed or foreign material. Infection may also occur through dental alveoli, and may account for the more common occurrence of the disease in young cattle when the teeth are erupting (Radostits et al., 2007). Actinomyces viscosus causes periodontal disease and subgingival plaques in hamsters fed a high carbohydrate diet, and also abscessation in dogs (Timoney et al., 1988) in which it is an opportunistic infection (Blood et al., 2007). The present report describes a case of actinomycosis due to A. viscosus involving a doe in a herd of 42 West African Dwarf (WAD) goats kept intensively at the Teaching and Research Farm, University of Agriculture, Abeokuta, Nigeria

A Review of the Published Anatomical Research on the African Giant Rat (Cricetomys gambianus Waterhouse)

Retrospective study of published anatomical research available online was carried out on the African giant rat (AGR) to determine the pattern, frequency and field of study that have received attention or a lack of it. The AGR (Cricetomys gambianus Waterhouse) has been recommended as a micro-livestock of Africa to supplement dietary animal protein with progressive use as landmine and tuberculosis detectors and pet animals. The applied usefulness of the pouched rats can be expanded with a thorough knowledge of their anatomy and morphophysiology however, the scientific bases for these functions are largely unknown. Various authors have provided insight into the anatomy of parts of the body system which reveal information and data upon which relevant inferences can be drawn for further research and determining the potentials and adaptive features of this animal. Scientific publications found on Google and Pubmed were used to access online International journals. Records of all anatomically inclined publications were collated and analyzed excluding abstracts, conference proceedings and unpublished research dissertations and thesis. All data were dated till December 2012. A total of 62 publications were found with reproductive anatomy ranking highest (33.9%) with 21 publications followed by, blood studies and angiology, osteology and renal studies (12.9%) 8 publications apiece then, neuroanatomy (11.3%) with 7 publications. Myology, arthrology and endocrine studies had no research finding. The authors propose a need for research focus on Africa’s 2nd largest micro-livestock and rare rodents (AGR) with policies and funding from government and the private sector in order to evolve an African model of rodent for scientific research.Keywords: African giant rat, anatomical research, review, African model, research focu

Spinal Cord Studies in the African Giant Rat (Cricetomys gambianus, Waterhouse)

Summary: The African giant rat, AGR, is known for advantageous behavioural patterns among which are cognition and dexterous locomotion. This study investigated the morphological, morphometric and possible functional aspects of the AGR spinal cord (SC) anatomy. Ten adult (5 males and 5 females) AGR were used to determine the gross and histological features of the SC which were typically of rodent features. The mean SC weight and length given as 2.50±0.24g and 15.87±0.24cm respectively for the male and 2.32±0.16g and 15.40±0.61cm for the female showed no sexual dimorphism (p<.05). A positive linear relationship between the tail length and SC weight were found in both sexes (r =0.81 males; r =0.95 females) suggesting significant contribution of the filum terminale to SC weight. Forty-three internal structures including nuclear aggregations and tracts were traced. Eight nuclear aggregations of neurons involved in nociception and limb coordination were observed to be prominent and larger than in laboratory rats. Same was noted for the dorsal, ventral and lateral funicular tracts which control the limbic system. This study provides morphometric baseline research information and delineates the functional aspects of the AGR SC anatomy. The information provided further strengthens the drive proposing the AGR as an indigenous research model for regional anaesthesia and locomotor disease.Keywords: African giant rat; spinal cord; spinal tract; nuclei; spinal segment; morphometry