Molecular characterization of bovine viral diarrhea virus and host genetic immune and biochemical responses in diarrheic buffalo calves.

Buffalo calves are highly susceptible to neonatal calf diarrhea (NCD), a major cause of morbidity, mortality, and economic loss in livestock production. Among the viral agents responsible, bovine viral diarrhea virus (BVDV) is one of the most common causes of NCD. The infection leads to significant financial losses due to calf mortality, treatment costs, reduced growth performance, and increased susceptibility to secondary infections. The study's goals were to examine the connections among SNPs, gene expression, the serum profile of biochemical and APPs marker changes, and the molecular detection and prevalence of BVDV in Egyptian diarrheal calves. Blood samples were obtained from 100 neonatal buffalo calves that were diarrheal and 100 that seemed healthy. The blood samples were then separated into EDTA tubes for whole blood collection used for RNA extraction and plain tubes (without anticoagulant) for serum collection. One hundred fecal samples were collected from diarrheic group for BVD screening using polymerase chain reaction (PCR), and those that tested positive with relatively high viral loads were further examined using PCR to amplify specific gene regions: the 5'UTR gene for BVD. Gene expression profile and nucleotide sequence variation for immune and antioxidant markers were assessed in healthy and diarrhea affected calves. BVDV was detected in 20% of the samples, according to PCR data. When the detected strains were matched to reference strains in Genbank, their identities ranged from 84.1 to 100%. Five identified samples' partial 5'UTR gene nucleotide sequences were uploaded to GenBank and assigned the accession codes PV243153, PV243154, PV243155, PV243156, and PV243157. Diarrheic group gene expression levels of SLC11A1, CD14, PTX3, IRF3, and ST1P1 were considerably (P < 0.05) higher than those of the control group. PRDX2, PRDX6, and GPX, on the other hand, were in the opposite range. Differences in the nucleotide sequences of the genes under investigation were observed between the diarrheic and healthy calves. Serum levels of APPs (Hp, SAA, Cp), ALT, AST, GGT, LDH, BUN, creatinine, triglyceride, cortisol and CRP were significantly (P˂0.05) increased in diarrheal buffalo calves, while serum levels of glucose, total protein, albumin, globulin, calcium, phosphorus, sodium, copper, zinc and iron were decreased. The findings of the study suggest that BVD is widespread in Egypt. The study's conclusions suggest that by using gene expression profiles and nucleotide sequences in genes related to immunity and antioxidants, buffalo calves could be chosen by marker-assisted selection (MAS) to predict and prevent diarrhea. Biochemical and APPs markers, as well as gene expression profiles and nucleotide sequence of genes under investigation, may also be used as proxy biomarkers for buffalo calves' diarrhea in order to make an effective management protocol, create effective vaccines, control strategies, and identify the most vulnerable risk period for disease occurrence.