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Assessing productivity and diversity of South African chicken genetic resourcesMtileni, B. J. 12 1900 (has links)
Thesis (PhD (Animal Sciences))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The current study was undertaken to determine the effectiveness of the current South African
chicken conservation programmes in conserving the genetic diversity of village chicken
populations. Village chicken farmer’s production constraints such as feed availability, chicken
mortality, prevalence of diseases and chicken sales were influenced by gender, age, wealth status,
production system, chicken flock size, type of chicken breed owned, accessibility of veterinary
services, availability of supplements, vaccines and shelter. Considerable phenotypic heterogeneity
in qualitative traits of indigenous chicken populations and their distributions in different regions of
South Africa revealed the absence of selection on a preferred phenotype, showing that the
population is not standardized. Genetic diversity studies using both microsatellites and mtDNA
markers demonstrated that the conservation flocks of South African chickens displayed
considerable genetic variability that is different from that of the assumed founder populations (field
chicken populations). The indigenous chicken mtDNA further revealed multiple maternal lineages
in South African chickens, where conservation flocks and field chicken populations shared these
major haplotypes A, D and E which are presumed to be of Chinese, South East Asia and Indian
subcontinent origin, respectively. The overall findings of the study increased awareness of the
importance of genetic management and utilization of indigenous chicken genetic resources of South
Africa. As a result, the study provides a base-line dataset to complement the decision-making
process on designing proper conservation strategies for South African indigenous chicken genetic
resources. / AFRIKAANSE OPSOMMING: Die huidige studie is onderneem om die doeltreffendheid van die Suid-Afrikaanse
hoenderbewarings programme in die bewaring van genetiese diversiteit in dorphoender bevolkings.
Dorp hoenderboere se produksie beperkinge soos voerbeskikbaarheid, hoender mortaliteit, die
voorkoms van siektes en hoenderverkope word beïnvloed deur geslag, ouderdom, rykdom status,
produksie sisteem, hoender kudde grootte, tipe hoenderras, toegang tot veeartsenydienste,
beskikbaarheid van supplemente, inentstowwe en skuiling. Merkbare fenotipiese variasie in
kwalitatiewe eienskappe van die inheemse hoenderbevolking en hul verspreiding in verskillende
areas van Suid-Afrika, is aanduidend dat daar nie seleksie plaasvind vir ‘n voorkeur fenotipe nie,
wat dus toon dat die bevolking nie gestandardiseer is nie. Genetiese diversiteit studies met behulp
van beide mikrosatelliete en mtDNA merkers het getoon dat die bewaringskuddes van Suid-
Afrikaanse hoenders vertoon merkbare genetiese variasie wat verskil van die veronderstelde stigter
bevolkings (veldhoender populasies). Die inheemse hoenders mtDNA het verder onthul dat verskeie
moederlike afstammelinge in die Suid Afrikaanse hoenders, major haplotipes A, D, E wat afkomstig
is vanaf die Chinese, Suid-Oos Asië en die Indiese subkontitent onderskeidelik; gedeel word saam
met die bewaringskuddes en die veldhoender populasie. Die algemene bevindige van die studie
verhoog die bewustheid van die belangrikheid van genetiese bestuur en benutting van inheemse
hoender genetiese hulpbronne van Suid-Afrika. As gevolg hiervan, verskaf die studie ‘n basis-lyn
datastel vir die besluitnemingproses oor die ontwerp van ‘n ordentlike bewaring strategieë vir die
Suid-Afrikaanse inheemse hoender genetiese hulpbronne.
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