Individual genomic loci, transcript level and biochemical profile of immune and antioxidant markers associated with genetically identified bacterial mastitis in Shami goats in Egypt

Abstract

Background: Mastitis in goats is unquestionably a grave concern, with far-reaching implications for both animal well-being and productivity, while also presenting a potential threat to public health. Aim: The study aimed to compare between culture methods and multiplex PCR (m-PCR) in detection of the most 3 common mastitis causing pathogens (Staphylococcus aureus, E. coli, Streptococcus spp) and investigating the gene expression, single nucleotide polymorphisms (SNPs), serum concentrations of immunological and antioxidant indicators linked to mastitis in Shami goats. Methods: One hundred Shami does (fifty Shami goats with clinical mastitis and fifty normal goats taken as control group). The culture methods and m-PCR analysis were used to find the bacteria in the milk samples.Blood samples were obtained in order to assess some hemato-biochemical parameters, detect SNPs, and determine the expression of certain immunological and antioxidant indicators in the genes. Results: Culture method detected the pathogens causing mastitis in 90% of the milk samples, but m-PCR detected them in 100% of the milk samples. SNPs linked to mastitis resistance/susceptibility in examined does were detected through DNA sequencing of immunological and antioxidant indicators. Magnitude of gene expression varied significantly between the resistant and mastitis affected groups. Significant (P˂0.05) elevations were noticed in WBCs count, mainly neutrophils count, serum levels of BHB, NEFA, triglycerides, LDL-C, AST, ALT, ALP, creatinine, total protein, globulin, Ca, K, GPx, MDA, acute phase proteins and cytokines in mastitis affected does as compared to control. While RBCs count, PCV%, lymphocytes count, serum concentration of glucose, cholesterol, HDL-C, albumin, Na, Cl, P, GSH, SOD, catalase significantly (P˂0.05) diminished in mastitis affected does compared to healthy ones. APPs and pro-inflammatory cytokines scored high sensitivities and NPVs but TNF-α and SAA had the highest percentages of increase. Conclusion: The study confirmed that m-PCR is the most sensitive method for bacteria identification (S. aureus, E. coli and Strept. spp.) while SNPs in antioxidant and immunological genes may be important genetic indicators for mastitis risk or resistance in Shami does. In order to establish an effective management plan and forecast the most sensitive risk time for illness onset, gene expression profiles of the tested genes may also be employed as proxy biomarkers. TNF-α and SAA may be precious indicators for detection of caprine mastitis.