A comparison of phenotypic traits related to trypanotolerance in five west african cattle breeds highlights the value of shorthorn taurine breeds.

David Berthier,Guiguigbaza-Kossigan Dayo,Moana Peylhard,Laurence Flori,Seydou Bolly,Hassane Sakande,Sophie Thevenon,Isabelle Chantal,Souleymane Sylla

doi:10.1371/journal.pone.0126498

Abstract

BackgroundAnimal African Trypanosomosis particularly affects cattle and dramatically impairs livestock development in sub-Saharan Africa. African Zebu (AFZ) or European taurine breeds usually die of the disease in the absence of treatment, whereas West African taurine breeds (AFT), considered trypanotolerant, are able to control the pathogenic effects of trypanosomosis. Up to now, only one AFT breed, the longhorn N’Dama (NDA), has been largely studied and is considered as the reference trypanotolerant breed. Shorthorn taurine trypanotolerance has never been properly assessed and compared to NDA and AFZ breeds.Methodology/Principal FindingsThis study compared the trypanotolerant/susceptible phenotype of five West African local breeds that differ in their demographic history. Thirty-six individuals belonging to the longhorn taurine NDA breed, two shorthorn taurine Lagune (LAG) and Baoulé (BAO) breeds, the Zebu Fulani (ZFU) and the Borgou (BOR), an admixed breed between AFT and AFZ, were infected by Trypanosoma congolense IL1180. All the cattle were genetically characterized using dense SNP markers, and parameters linked to parasitaemia, anaemia and leukocytes were analysed using synthetic variables and mixed models. We showed that LAG, followed by NDA and BAO, displayed the best control of anaemia. ZFU showed the greatest anaemia and the BOR breed had an intermediate value, as expected from its admixed origin. Large differences in leukocyte counts were also observed, with higher leukocytosis for AFT. Nevertheless, no differences in parasitaemia were found, except a tendency to take longer to display detectable parasites in ZFU.ConclusionsWe demonstrated that LAG and BAO are as trypanotolerant as NDA. This study highlights the value of shorthorn taurine breeds, which display strong local adaptation to trypanosomosis. Thanks to further analyses based on comparisons of the genome or transcriptome of the breeds, these results open up the way for better knowledge of host-pathogen interactions and, furthermore, for identifying key biological pathways.

Highlights

Animal African Trypanosomosis (AAT), a neglected tropical disease, affects cattle and dramatically impairs the development of livestock production systems in sub-Saharan Africa [1], [2], [3]
African Zebu (AFZ) or European taurine breeds usually die of the disease in the absence of treatment, whereas West African taurine breeds (AFT), considered trypanotolerant, are able to control the pathogenic effects of trypanosomosis
We demonstrated that LAG and BAO are as trypanotolerant as NDA

Summary

Introduction

Animal African Trypanosomosis (AAT), a neglected tropical disease, affects cattle and dramatically impairs the development of livestock production systems in sub-Saharan Africa [1], [2], [3]. African Zebu breeds (AFZ), as well as European taurine breeds (EUT), are highly susceptible to the disease caused by three tsetsetransmitted trypanosome species, Trypanosoma congolense, T. vivax and T. brucei brucei [11]. A single study based on an experimental infection compared LAG and Borgou (BOR) breeds [28], the latter being a stabilized admixed breed between AFT and AFZ representative of the West African bovine hybrid zone [29], [30], but the study lacked a proper susceptible control breed and used a trypanosome species, T. brucei brucei, which is usually less pathogenic than T. vivax and T. congolense [11]. Shorthorn taurine trypanotolerance has never been properly assessed and compared to NDA and AFZ breeds.

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