Evaluating gene expression and biomarkers for mastitis resistance in Barki sheep

The aim of this study was monitoring health status of mastitic Barki ewes using candidate gene approach, gene expression and serum profile of inflammatory and antioxidant markers. A total of 70 ewes were allocated into two equal-sized groups: healthy and ewes have a history of mastitis. DNA sequencing of IFN-γ (365-bp), IL-4 (285-bp), TNF-α (273-bp), MYD88 (660-bp), CCL5 (360-bp), TLR4 (256-bp), TLR9 (414-bp), LTF (299-bp), PRLR (891-bp), CAT (300-bp), GPX1 (221-bp), Keap1 (360-bp), OXSR1 (357-bp), ATOX1 (433-bp), GST (480-bp) and Nrf2 (340-bp) revealed single nucleotide polymorphisms (SNPs) between healthy and mastitic ewes. Levels of IFN-γ, IL-4, TNF-α, MYD88, CCL5, TLR4, TLR9, LTF, PRLR, Keap1 and OXSR1 genes expression were significantly up-regulated in ewes affected with mastitis than resistant ones. Meanwhile CAT, GPX1, ATOX1, GST, and Nrf2 genes elicited an opposite trend. There is a significant elevation of activity of AST, LDH, Hp, CP, SAA, IgG, MDA, and NO levels (P < 0.05), along with reduction of total protein, albumin, GSH, GPx, catalase and SOD (P < 0.05) in mastitic ewes. The findings of this study supported the hypothesis that SNPs in immune and antioxidant genes could be important genetic markers for mastitis susceptibility or resistance in Barki ewes. The examined genes' gene expression profiles may also be utilized as surrogate biomarkers to establish an efficient management regimen and forecast the period of time at which a disease is most likely to manifest.