RESUMO
Tick-borne diseases (TBDs) of livestock are endemic across various parts of tropical countries. Theileriosis is one such economically important TBD, caused by the Theileriidae family of organisms, which is transmitted by ticks. Theileria annulata, the causative agent of tropical theileriosis, contributes a significant loss to the dairy sector by causing anorexia, high fever, anemia, inflammatory changes in vital organs and icterus, thus, a loss in milk yield. Though vaccines are available, their protective efficacy is not absolute, and treatment is limited to early diagnosis of the causative agent. Routinely, microscopic identification of piroplasms in the erythrocytes (Giemsa-stained) of infected animals or schizonts in lymph node biopsies are practiced for diagnosis. PCR-based techniques (multiplex, uniplex, nested and real-time) have been reported to perform well in diagnosing active infection. Several attempts have been made using serological assays like Dot blot, ELISA and ICT, but the results were of variable sensitivity and specificity. Recombinant proteins like the Theileria annulata merozoite surface antigen (Tams1) and Theileria annulata surface protein (TaSP) have been explored as antigenic candidates for these assays. In the present study, we predicted an immunogenic peptide, i.e., TaSP-34, from the TaSP using various computational tools. The predicted peptide was custom synthesized. The diagnostic potential of the peptide was assessed by indirect plate ELISA to detect the bovine-IgM against Theileria annulata. Alongside, a recombinant truncated TaSP (rTaSP(tr)) was expressed and purified, which was used to compare the performance of the peptide as a diagnostic candidate. The IgM-based peptide ELISA was 100% sensitive and 92.77% specific as compared to PCR (Tams1 targeting), while 98.04% sensitivity and 97.44% specificity were observed in comparison with rTaSP(tr) ELISA. Almost perfect agreement between peptide ELISA and Tams1 PCR was observed with a Cohen's kappa coefficient (κ-value) of 0.901 and agreement of 95.31%. Further, the κ-value between the peptide ELISA and rTaSP(tr) ELISA was found to be 0.95, and the agreement was 97.65%, which shows a good correlation between the two tests. The findings suggest that the TaSP-34 peptide can be an efficient and new-generation diagnostic candidate for the diagnosis of T. annulata. Furthermore, the peptide can be synthesized commercially at a larger scale and can be a cost-effective alternative for the protein-based diagnostic candidates for T. annulata.
RESUMO
Present study was conducted to investigate the impact of temperature humidity index (THI) on expected breeding value (EBV) for daily milk yield (DMY) and monthly test day fat% (MTDF%) and monthly test day SNF% (MTDSNF%) of Murrah buffaloes at ICAR-National Dairy Research Institute, Karnal. 302,101 records of DMY and 9864 records each on MTDF% and MTDSNF% buffaloes spanned over 20 years (1994 to 2013) from NDRI, Karnal, and meteorological were collected from ICAR-CSSRI, Karnal. The year was classified into three zones: non-heat stress (NHSZ), heat stress (HSZ), and critical heat stress zone (CHSZ) based on THI. The heritability (h2) estimates for DMY, MTDF%, and MTDSNF% in NHSZ were 0.432 ± 0.054, 0.090 ± 0.004, and 0.070 ± 0.002; in HSZ 0.491 ± 0.073, 0.112 ± 0.003, and 0.052 ± 0.001; and in CHSZ 0.524 ± 0.077, 0.116 ± 0.004, and 0.092 ± 0.003, respectively. The repeatability (r) for DMY, MTDF%, and MTDSNF% in NHSZ were 0.528 ± 0.006, 0.166 ± 0.007, and 0.135 ± 0.007; in HSZ 0.572 ± 0.007, 0.198 ± 0.006, and 0.077 ± 0.006; and in CHSZ 0.599 ± 0.008, 0.217 ± 0.004, and 0.156 ± 0.009, respectively. EBV for DMY and MTDF% was maximum in NHSZ (8.85 kg and 7.85%) and in HSZ (7.27 kg and7.78%) and lowest (6.90 kg and 7.77%) at CHSZ. For MTDSNF%, EBV was highest during NHSZ (9.6403), declined to 9.6265 at HSZ, and marginally elevated to 9.6271 at CHSZ. Impact of climatic factors on milk production and constituent traits is vital, and proper management should be followed during the heat stress and critical heat stress periods to improve the production performance of Murrah buffaloes.
