Heat shock protein 70 polymorphism associated with physio-biochemical parameters of Awassi and Arabi Iraqi sheep

Abstract EN

Heat shock proteins (HSPs) are a group of proteins that provide thermotolerance in cell and protect cells against environmental stress.

Polymorphisms of the HSP70 gene associated with thermotolerance in farm animals.

Thus, the current study aimed to evaluate the association of polymorphism in the HSP70 gene on physio-biochemical parameters in Awassi and Arabi sheep.

Two breeds of sexually mature and healthy sheep that aged between 2 to 3 years were involved in this study, including 75 animals of Awassi (22 male: 53 female) and 75 animals of Arrabi (15 male: 60 female).

Genomic DNA was extracted from whole blood then genotyping analysis and sequencing were performed for each genotype.

In the present study, single strand conformation polymorphism (SSCP) analysis reveals two genotypes (TT and TG) in HSP70 (exon 4) of sheep.

One missense SNPs c.33163685T>G was identified in exon 4 HSP70 gene that was responsible on the observed heterogeneity in both breeds.

Hematological analysis indicate that the amount of RBC, Hb, PCV% and MCHC were significantly higher (P<0.05) in awassi than Arabi, in summer than winter and in TT than TG genotype.

Comparison of analysis of leukocyte profile demonstrated that WBC, lymphocyte, lymphocyte % and granulocyte % mean were higher in awassi breed, winter season and TT genotype.

Biochemical analysis refer that the levels of T3 and T4 were found to be extremely highly expressed in the Arabi than awassi, in the winter season and TG genotype.

In conclusion, TT genotype was high tolerance of to heat stress, higher frequency of this genotype in Arabi breed make this breed better thermos-tolerance with heat stress conditions.