International Science and Technology Journal of Namibia

Effects of dietary inclusion of black soldier fly (Hermetia illucens) larvae meal on growth performance and carcass yield of broilers

D. Heita — 2023-07-31

Black soldier fly larvae meal (BSFLM) has been proven as a potential low-cost protein source that can replace soy bean meal in poultry diets. A study was conducted to determine the feed intake, growth performance and carcass characteristics of broilers fed a diet varying in inclusion levels of BSFLM. Day-old ROSS 308 broiler chicks (n = 60) reared on a starter commercial diet for the first three weeks were randomly allocated to one of the three broiler grower dietary treatments using a completely randomised design. The broiler grower diets were the control diet, which contained no BSFLM (T1), T2 contained 5% BSFLM and T3 contained 10% BSFLM replacing soybean meal. There was a significant difference (p < 0.05) in the feed intake, where the control had the highest intake followed by 5% BSFLM inclusion. There was a significant difference (p < 0.05) in the final live weight where the 5% BSFLM had the highest among the treatments and the control was the lowest. The inclusion of BSFLM had a significant (p < 0.05) effect on the carcass weight and thighs weight with the highest mean for the 5% BSFLM inclusion and the lowest with the control treatment. There was no significant (p > 0.05) difference in the slaughter weight, wings, drumstick and breast muscles among the treatments. The study concludes that the inclusion of BSFLM at 5% had a positive effect on the growth performance, carcass yield and characteristics of broiler chickens.

Effect of arbuscular mycorrhizal (AM) fungi on growth and physiological responses of water stressed Azadirachta indica A. Juss seedlings

Paulina Pomwene Fendina — 2023-07-31

A neem nursery experiment was conducted to investigate the effect of AM on germination, growth, physiological traits and to evaluate the effect of AM fungi in tolerating water stress. The experiment comprised of two treatments; AM-inoculated and non-inoculated three months old neem seedlings, of which the treatments were subjected to water stress condition. A slightly higher germination rate
of 7.77 % was observed in the Glomus mosseae inoculated treatment relative to the non-inoculated treatment. Moreover, water stress exhibited significant reductions in various morphological parameters and relative water content, with more effects pronounced in non-inoculated treatment. The AM–inoculated treatment showed prompt recovery during water resumption period which was reflected in the reduction of relative stress injury. Proline and soluble carbohydrate contents were significantly more in leaves of non-inoculated treatment as compared to AM-inoculated treatment during water stress. Although, water stress caused a reduction in mycorrhizal abundance, growth, and soil moisture content, AM considerably maintained plant growth performance hence retained better soil moisture content.

Towards understanding rainfall variability in Namibia

E.G. Kwembeya — 2023-07-31

Namibia experienced a severe multiyear drought period between 2010 and 2019, which resulted in extremely low reservoir and groundwater levels. This study aimed at investigating the spatial and temporal variations of rainfall during the period under review. A total of 4340 rainfall records, with associated maximum monthly temperature, minimum monthly temperature and average ground temperature data were obtained from 57 weather stations across the entire country. Ordinal logistic regression analysis was used to model the relationship between the total rainfall received and selected explanatory variables namely; season, region, minimum air temperature, maximum air temperature and average ground temperature as predictors. This study revealed an increased probability of receiving higher rainfall as maximum and minimum monthly air temperatures increase. However, an increase in average monthly ground temperatures revealed a significant negative effect on rainfall. Additionally, an annually decreasing rainfall trend between 2010 and 2019 was detected with significantly higher rainfall being obtained in summer months than in winter months. This downward rainfall trend in the last decade suggested an intensification of drought, especially in Erongo, Karas, Hardap and Kunene regions. To this end, this study has revealed that having more weather stations could help in the monitoring of rainfall trends for rainwater management planning. This calls for adaptive responses which include inter alia diversification options, the expansion of irrigated agriculture and smart agriculture to ensure food security in the country.

Microbial quality of peanut butter manufactured by small-scale producers at two popular open-air markets in Lusaka Mary Ngulube and Evans Kaimoyo∗

Mary Ngulube — 2023-07-31

To contribute to the safety and quality of peanut butter manufactured by small-scale producers and consumed in Zambia, six samples from two popular local markets in Lusaka and six others from commercial retail outlets were procured and analyzed for microbial quality. Various fungal genera including Mucor, Alternaria, Cladosporium, Penicillium, Trichothecium and Trichophyton were identified, with Cladosporium being the most predominant. The main bacterial genus isolated and identified was Bacillus, and for both fungi and bacteria, total microbial loads in peanut butter samples produced by small-scale manufacturers were found to be significantly higher than those in samples from commercial retail outlets. The high microbial loads present a public health challenge
necessitating an urgent need for good manufacturing and hygiene practices to help minimize fungal
and bacterial contamination, improve the quality of the products and forestall the potential for
food-borne disease outbreaks.

Ethnomycological study of Termitomyces mushrooms at Judea-Lyabboroma and Katima rural in the Zambezi Region, Namibia

A Mukwata — 2023-07-31

In this study, face-to-face interviews were conducted to collect data on the indigenous uses and traditional knowledge of Termitomyces mushrooms in Judea-Lyabboroma and Katima rural, Zambezi Region, Namibia. The results showed that Termitomyces were used in the form of powder or paste to heal diseases such as cancer and kidney problems, sexually transmitted infections (STIs), heart disease, severe diarrhea, cancer-related diseases, kidney problems and in the prevention of miscarriages. In both constituencies, the pseudorhiza for the Termitomyces mushroom was reported to be an important part that is used in healing various diseases. The results not only motivate the research team to continue finding more possible potential benefits that Termitomyces can provide but to encourage validation and pharmaceutical studies to be carried out for drug discovery on these mushrooms in order to provide conclusive results on the potential use of the Termitomyces in Namibia and beyond.

Phylogenetic Diversity of Endophytic Bacteria Communities from marama bean Tylosema esculentum (Burchell.) A. Schreiber

Jean D. Uzabakiriho — 2023-07-31

Tylosema esculentum is a nutritious drought-avoiding and climate change contender plant for future agriculture. It is endemic to the Kalahari Desert. This study assessed the density, diversity and distribution of endophytic microbial community structures associated with leaves, stems and tuberous roots of T. esculentum in Eastern Namibia using culture-dependent methods. Analysis of
Variance with pairwise comparison revealed differences in bacterial density between below and above ground. Endophytic bacterial isolates were identified and grouped into 24 genera and three phyla. Proteobacteria were the most represented (67.4%) followed by Firmicutes (23.7%) and Actinobacteria (4.3%). Shannon diversity index revealed a significant difference between the tuberous roots and
leaves (p = 0.005) and stems (p = 0.006) microbial communities. The PCA confirmed these findings. Our results suggested that the microbial community composition was mainly governed by the plant parts rather than the location or sampling time. The 16S rDNA based phylogenetic analysis showed that all these microbial communities fell into two clades distinct from known cultivated bacteria from NCBI. Our sequences have shown similarities with the ones occurring in water-stressed environments with plant growth promoting traits. In conclusion, T. esculentum bean lives in community with a large diversity of potentially plant growth-promoting bacteria

The Belief that male circumcision reduces HIV transmission is a key predictor in circumcision status

Isak SK Amadhila — 2023-07-31

The aim of this research was to establish the circumcision prevalence and the factors associated with the uptake of voluntary medical male circumcision (VMMC) among health science students. A crosssectional study was carried out between July - August 2019. An anonymized questionnaire with 22 items was self-administered to health science students. Analysis of Variance (ANOVA) was performed on the demographic and beliefs information obtained. Logistic regression models were used to explain the associations, with the significance level set at α = 0.05. Eighty-six (65.6%) males were circumcised out of the 131 participants. The majority of students were enrolled for Medicine (61%). The following factors were associated with circumcision: Kavango ethnic group, OR 2.70 [CI 0.84- 6.60]; Holding the belief that circumcision reduces HIV transmission risk OR 3.96 [CI 0.42 - 2.39]; VMMC campaigns involving local celebrities OR 5.83 [CI 0.20 - 3.43]. This study highlights the need for upscaling VMMC among Health Science students via social mobilization and advocacy.

3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5E,7Eoctatriene is an important Namibian cytotoxic lead compound

Michael Knott — 2023-07-31

The selectivity of this compound, together with that of the famed Halomon, was tested for different solid tumor
cell lines with respect to the CCRF-CEM leukemia cell lines according to the disk diffusion assay. The selectivity
of the two compounds were similar in many respects, however Halomon had an IC50 (µ/mL) of 0.37 versus 1.3
for 3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5E,7E-octatriene (Vogel et al., 2014). In addition,
3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5E,7E-octatriene was also evaluated for cytotoxic effects
on an esophageal cancer cell line (WHCO1) and had an IC50 (µM) of 8.5, which is greater cytotoxicity in this
assay compared to the known anticancer drug cisplatin, which had an IC50 (µM) of 13 (Antunes et al., 2011).
Using nuclear magnetic resonance and mass spectrometry, I was also excited to find that this compound is also
the major metabolite found in Namibian Plocamium cornutum species. It is relatively easy to isolate in reasonably
good quantities using only liquid-liquid partition separation techniques. In addition, the surprising yields enable
numerous additional in vitro or in vivo testing to be carried out on this compound here in Namibia.