Abstract

Objective: To evaluate the role of interferon gamma (IFN-γ) gene in Haemonchus contortus (H. contortus) resistant in Garole/Sahabadi breed of sheep. Methods: Five Garole sheep (Group I) consistently showing low egg per gram in faeces (≤ 150) and another five Garole sheep(Group II) which had high egg per gram (≥ 500) were challenged with third-stage (L3) H. contortus larvae with 500 larvae/kg body weight. Five Sahabadi sheep (Group III) which were known to be susceptible to H. contortus were also fed with the same dose. Blood was collected from each group at different date of infection, viz. 0 day, 7 days and 14 days of post infection. The ovine IFN-γ was partially isolated and sequenced including intron and exon regions from six Garole sheep and three Sahabadi sheep prior to infection. The level of messenger ribonucleic acid of IFN-γ was evaluated by means of real-time PCR at different days of post infection. Results: In addition to one single nucleotide polymorphism at exon 3 of IFN-γ gene in three resistant Garole sheep, the level of mRNA in two susceptible groups was found significantly higher (P ≤ 0.05) as compared to the resistant group in the present study. Conclusions: We could clearly identify a single cytokine gene which is differentially expressed between the resistant and the susceptible animals that could be a potential target for identifying the genetic marker of Haemonchus resistance. Finding of one single nucleotide polymorphism at exon 3 in three resistance Garole sheep might have novelty.

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