Assessing the Sustainability of Thryonomys swinderianus Hunting in Ogoni Land

Background: Thryonomys swinderianus is a renewable natural resource and is a major mammal that constitute what is termed bushmeat in Ogoni land. Between July 2017 and June 2018, 10320Kg of Thryonomys swinderianus meat or 2580 animals were obtained from the wild by hunting. The number of animals removed compared to its population as at June 2017 prompted this study. Aim: The aim of the study is to ascertain the sustainability of this level of harvest in Ogoni land. Methods: The Robinson and Redford model of 1991 was used to assess the sustainability of this harvest in this study. The maximum possible production of Thryonomys swinderianus from July 2017 to June 2018 was 3.5/Km² and the proportion of this production to be harvested sustainably is 2.1/Km² or 8.4Kg/Km². The actual harvest within this period was 2.58/Km² or 10.32Kg/Km². Results: The actual harvest of 2.58/Km² is greater than the maximum sustainable yield of 2.1/Km² and as such, the harvest of 2.58 Thryonomys swinderianus per square kilometer per year is not sustainable in Ogoni land. Conclusion: The unsustainable harvest of Thryonomys swinderianus should as a matter of urgent concern be monitored and regulated. Continuation of this rate of removal will diminish the renewal rate and lead to the extinction of Thryonomys swinderianus in the near future.

Qualitative characteristics of Thryonomys swinderianus swinderianus and Thryonomys swinderianus gregorianus

Cane rat, a micro livestock currently being domesticated has the potential to increase animal protein sources. This study examined the qualitative characteristics of Thyryonomys swinderianus swinderianus (Tss) and Thryonomys swinderianus gregorianus (Tsg). Three hundred and thirty five cane rats were sampled. Seven qualitative characters were coded. These included: Shape of Head (SH), Eye Placement (EP), Ear Shape (ES), Body Pelage (BP), Tail Shape (TS), Tail Colour (TC), Breed (B). The qualitative characters were scored on the individual animals. This measures were analysed using frequency distribution and chi-square analysis. In the Tss population, 89.23% of the animals had broad heads, 10.77% had narrow heads. The broad heads animals had broad tip ear (89.236) have brown and yellow - belly white body colour (89.23%). Their tail is broad base and thin out to tip (87.69%) although a few (1.54%) had broad base and even out to tip. All the broad heads (89.23%) brown and yellow-belly white animals (100.00%) had black and hairy tail. In the Tsg population, 87.06% of the animals had narrow heads, (12,94%) had broad heads. The narrow heads animal (86.67%) had ear with broad tip and have black and yellow-belly white body colour (86.67%). The tail is broad base and thin out is tip (80.39%). All the narrow heads (87.06), black and yellow-belly white (99.61%) animals had black and hairy tail

Organ weight, serum biochemistry and gut microbial counts of Thryonomys swinderianus fed diet supplemented with Vernonia amygdalina leaf meal

The study investigated the effect of Vernonia amygdalina (VA) leaf supplementation on organ weight and gut microbial count of Thryonomys swinderianus. Thirty-six weaner grasscutters of mixed sexes were allotted randomly to six treatments (A, B, C, D, E, and F) in a completely randomized design for a nutritional trial of 8 weeks. At the end of the experiment, caecum, kidney, liver, lungs, intestine and the heart were excised to determine their weights and the intestinal/caecal contents and scrapings were obtained to determine the fungi and bacteria population. Data collected were analyzed using one-way Analysis of Variance (ANOVA). The VA supplementation had significant effect (p<0.05) on relative organs with a range of 0.47 – 0.60%, 0.40 – 0.62%, 1.20 – 2.83%, 0.52 - 0.58%, 5.53 – 12.91%, 714.00 – 960.00g, 494.00 – 781.00g and 479.00 – 747.00g for lungs, heart, liver, kidney, intestine, live weight, eviscerated and carcass weight of the grasscutter respectively, with a smaller relative weight of the kidney from 3g/kg VA supplementation upwards. The serum biochemical parameters were also significantly affected by VA supplementation. There was a decrease in alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase but were within the normal range required for rodents. Total protein and Albumin were significantly improved by the supplement while total bilirubin was variable with a significant decrease prior to 4gVA supplementation. Microbial populations in the intestine and ceacum were reduced to varying extent by the supplement. It could be concluded that VA supplementation reduced intestinal and caecal microbes and increased the live and carcass weights but decreased relative weights of selected organs in the grasscutter.

Effects of strain, live weight and micro-environment on body weight development of cane rat (Thryonomys swinderianus) in the humid tropics

Interactive effects of strain, live weight and a non-genetic factor namely micro-environment on the live weight development of cane rats reared in captivity were investigated over a seven-month period. A total of seventy-nine (79) cane rats (Thryonomys swinderianus) originating from three different sources (strains) and of four body weight categories were used for the study. The treatment design was 4x3 Factorial of Live-weightXStrain randomlyassigned to 3 Houses (block) using RCBD, while statistical analysis utilized GLM procedure of SAS® (1999). Data were recorded monthly based on Treatment-combinations and House-micro-environment. Results revealed that effects of strain, live weight category and house-micro-environment on strains were significant. Consequently, interactive effect of strainXhouse-micro-environment was found most depressing on awole>FRIN>Bamidele, while strainXlive-weight category interaction exerted most positive influence on Lawole strain which demonstrated the highest ability for body weight development than other two strains. Findings revealed that interactive effect of STRxHME was most significant on weight development. Bamidele strain was identified as most acclimatized and adaptable of the three strains based on least body weight sensitivity and variation between HMEs. Different strains of cane rat in captive rearing systems would exhibit different and specific reaction norms under interaction of strain, Body weight and House-micro-environment. This knowledge is useful for feeding regimes, husbandry and reeding schemes for cane rats in humid tropics.

Estimation of variance components for body weight of grasscutters (Thryonomys swinderianus) using a repeatability model

Genetic parameters for growth and other economically important traits of grasscutters are scant in literature. Therefore, the aim of this study was to estimate variance components,heritability and repeatability of body weight of grasscutters using restricted maxim um likelihood method in a repeatability animal model. Sixteen grasscutter families were used for the study. Each family was made up of one male and four females. Each grasscutter has four repeated records giving a total of 320. The pedigree consisted of 80 animals, progenies of 16 sires and 16 dams. Fixed factors included in the model were family and sex. The WOMBAT program was used for the analysis. The heritability of body weight of grasscutters ranged from 0.23±0.04 to 0.68±0.10, thus implying that mass selection will be appropriate for this population. The repeatability estimates ranged from 0.82±0.08 to 0.93±0.11. It can be concluded that the number of body weight records was a good indicator of the animal's growth potential and that mass selection will be reliable.