Published in Scientific Papers. Series D. Animal Science, Vol. LXVII, Issue 2
Written by Karima BELGUESMI, Asma AWADI, Imed BEN SLIMEN, Hichem BEN SLIMEN
Blood parasites, particularly those of the Anaplasma marginale, Babesia and Theileria spp., present a challenge to successful livestock farming. In the present work, PCR analysis was carried out to detect possible infection by the above-mentioned parasites in three cattle populations from northern Tunisia. We also sequenced exon 2 of the BoLA-DQA1 gene in 17 Holstein cattle. Our results showed a low level of infection by the screened parasites, with prevalences of 8.8%, 5.9% and 0.0% for Theileria spp., Anaplasma mariginale and Babesia ssp., respectively. On the other hand, a total of 11 alleles were observed in the BoLA-DQA1 gene in the analysed samples. Six alleles were detected for the first time. BoLA-DQA1*10011 and *0101 alleles were the most frequent. These two alleles were also the most frequent in all Holstein cattle populations so far studied. Finally, four and eight amino acid positions were under positive selection by DATAMONKEY and PAML, respectively. Such selection, associated with high polymorphism observed in the BoLA-DQA1 gene, might suggest an important qualitative and quantitative parasite pressure that would favour distinct allele types.
[Read full article] [Citation]
