INTERNATIONAL JOURNAL OF AGRICULTURAL TECHNOLOGY

Volume 14, No. 07, Month DECEMBER, Year 2018, Pages 1525 - 1534

Degradation of troponin-t associated with calpain/ calpastatin genes expression in native thai beef cattle fed different levels of energy

Non-see, M., Lukkananukool, A., Polyorach, S., Sommart, K., Sazili, A. Q. and Chaosap, C.

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The influence of dietary energy level on the degradation of troponin-T protein and expression of calpain and calpastatin genes in native Thai cattle was determined. Eighteen steers (at 200 days old and average body weight of 100 ± 20 kg) were randomly assigned to 3 dietary treatment groups of different metabolizable energy: Treatment 1 [(8.9 MJ/ kg DM; n=6), Treatment 2 (9.7 MJ/kg DM; n=6) and Treatment 3 (10.5 MJ/kg DM; n=6)]. The diets were in the form of fermented total mixed ration (FTMR). At the end of 520 days of feeding, the steers attained 300 ± 10 kg BW at slaughter. The Longissimus dorsi m. samples collected within 2 d postmortem were further aged for 14 d for the troponin-T degradation immunoblot analysis while, the CAPN1, CAPN2, and CAST genes expression analyses only used samples at 2 d postmortem. The relative bands intensities of intact (37 kDa) and degraded troponin-T (30 kDa) were unaffected by the dietary treatments (p>0.05). Higher 37 kDa (p<0.01) and 30 kDa (p<0.001) troponin-T proteins expression were noted at 2 d and 14 d post-mortem, respectively. The CAPN1, CAPN2, and CAST genes expression remained unaffected (p>0.05) by the dietary treatment. Nonetheless, significant associations were observed between CAPN2 and CAST genes expression (r=0.93; p<0.0001), and between CAPN1 gene expression and 30 kDa troponin- T proteins expression at 14 d postmortem (r=0.58; p<0.05). This study concluded that neither troponin-T proteins nor calpain/ calpastatin genes expression were influenced by dietary energy levels in fattened native Thai cattle. The associations between CAPN2 and CAST genes expression, and between CAPN1 gene expression and 30 kDa troponin-T proteins expression at 14 d postmortem suggest the involvement of CAPN1 in myofibrillar proteolysis during the 14 d postmortem ageing of Longissimus dorsi m. in native Thai cattle.

Keywords

Dietary energy, troponin-T, calpain, calpastatin, native Thai cattle

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