Browsing by Author "Munga, Leonard"

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    Dietary Mycotoxins: An Overview on Toxicokinetics, Toxicodynamics, Toxicity, Epidemiology, Detection, and Their Mitigation with Special Emphasis on Aflatoxicosis in Humans and Animals
    (MDPI, 2024-11) Kibugu, James; Munga, Leonard; Mburu, David; Maloba, Fredrick; Auma, Joanna E.; Delia, Grace; Lindahl, Johanna F.
    Mycotoxins are secondary metabolites of filamentous fungi and ubiquitous dietary contaminants. Aflatoxins, a group of mycotoxins with high prevalence and toxicity, have raised a high level of public health concern, the most prevalent and toxic being aflatoxin B1 (AFB1). Many aspects appertaining to AFB1 poisoning are not well understood. Yet this information is necessary to devise appropriate surveillance and mitigation strategies against human and animal aflatoxicosis. This review provides an in-depth update of work carried out on mycotoxin poisoning, particularly aflatoxicosis in humans and animals, to identify gaps in knowledge. Hypotheses explaining the functional significance of mycotoxins in fungal biology and their dietary epidemiological data are presented and briefly discussed. The toxicology of aflatoxins and the challenges of their mitigation are discussed in depth. It was concluded that the identification of potential mycotoxin-hazard-prone food items and quantification of the associated risk of cancer ailments in humans is a prime priority. There is a dearth of reliable sampling methodologies for estimating AFB1 in animal feed. Data update on AFB1 in animal feed and its implication in animal production, mitigation strategies, and elucidation of risk factors to this hazard is required. To reduce the burden of aflatoxins, surveillance employing predictive technology, and biocontrol strategies seem promising approaches.
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    Expression of trypanotolerance in N’Dama x Boran crosses under field challenge in relation to N’Dama genome content
    (BMC, 2011) Orenge, Caleb; Munga, Leonard; Kimwele, Charles; Kemp, Steve; Korol, Abraham; Gibson, John; Hanotte, Olivier; Soller, Morris
    Background: Animal trypanosomosis in sub-Saharan Africa is a major obstacle to livestock based agriculture. Control relies on drugs with increasing incidence of multiple-drug resistance. A previous mapping experiment in an F2 population derived from the indigenous trypanotolerant N ’ Dama cattle crossed to susceptible (Kenya)-Boran cattle under controlled challenge, uncovered a number of trypanotolerance QTL (T-QTL). The present study was to determine expression of N ’ Dama trypanotolerance in a backcross to the Boran under conditions of field challenge, and whether chromosomal regions associated with trypanotolerance in the F2 experiment showed similar effects in the BC population. Methods: 192 backcross animals to the Boran were produced in six batches from June 2001 to December 2006. At one year of age animals were moved to the field and exposed to natural challenge over about one year in Southwest Kenya (Narok). The animals were individually recorded weekly for body weight, packed cell volume, parasitaemia score, and drug treatments, and were genotyped using 35 microsatellite markers spanning 5 chromosomes found in the F2 study to harbour T-QTL. Results: The F1 were most trypanotolerant, Boran least, and BC intermediate. Females showed distinctly higher trypanotolerance than males. There was a positive correlation in the BC population between trypanotolerance and number of N ’ Dama origin marker alleles. QTL mapping revealed T-QTL distributed among all five targeted chromosomes, corresponding in part to the results obtained in the F 2 experiment. Conclusions: N ’ Dama origin trypanotolerance is expressed in a BC population under field conditions in proportion to N ’ Dama origin marker alleles. Consequently, marker assisted selection in such populations may be a means of increasing trypanotolerance, while retaining the desirable productive qualities of the recurrent parent.
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    The Orma Boran—ten years of field observations
    (Towards Increased Use of Trypanotolerance: Current Research and Future Directions, 1994) Munga, Leonard
    In 1913 Balfour reported Bos indicus cattle in the Koalib area of Sudan which he claimed were immune to trypanosomiasis (Balfour, 1913). Since that date trypanotolerance has been reported in other Bos indicus breeds in Sudan, Zaire, Uganda and Kenya (see Dolan, 1987 for references). Yet, despite these reports in the literature, little effort has been made to investigate the nature or extent of differential susceptibility to trypanosomiasis amongst