Sarcoplasmatic and myofibrillar protein changes caused by acute heat stress in broiler chicken

Abstract

Acute heat stress (AHS) modifies the structure of myofibrils affecting functional properties of meat, mainly the water holding capacity. This experiment aimed to identify changes in proteolysis and migration between the myofibrillar and sarcoplasmatic fractions due to pre-slaughter AHS. Myofibrillar fragmentation index (MFI), SDS-PAGE, western blot of vinculin (WB) and shear force (SF) were determined. Six hundred broilers (Gallus gallus) were slaughtered in three different days (ST). In each ST, groups of ten animals were placed in transport crates and submitted to AHS (35ºC, 75 -85% RH) for 2 hours. Simultaneously, the non-stressed broilers (NS) were kept in thermoneutral environment (22ºC, 83 ± 6.6% RH) within the crates in the same density. After slaughter, the breast muscles were kept refrigerated until the withdrawal of all samples (0, 1, 2, 6 and 24 hours after slaughter). Sampling within AHS and NS birds was collected according to lightness value (normal L* ≤ 49, and high ≥ 51), except for determination of MFI and SF. The lightness was used later to perform SDS-PAGE and WB analyses. MFI kinetics showed that the fragmentation rate was superior in animals NS, indicating that AHS can harm proteolysis and rate of myofibrillar fragmentation. However, the extent of fragmentation did not change, as well as SF values. SDS-PAGE for Troponin fragments indicated a differentiated pattern between AHS and NS. The WB did not show alterations in vinculin fragmentation. Modifications in sarcoplasmatic fraction are observed in meat with high L*values, independent of environmental condition. Key words: broiler, heat stress, lightness, fragmentation index, shear force ALTERAÇÕES NAS PROTEÍNAS SARCOPLASMÁTICAS E MIOFIBRILARES EM FRANGOS DE CORTE CAUSADAS POR ESTRESSE TÉRMICO AGUDORESUMO: O estresse térmico agudo (ET) causa alterações na estrutura das miofibrilas, afetando propriedades funcionais da carne, principalmente a capacidade de retenção de água. Identificaram-se mudanças na proteólise e migração entre as frações miofibrilar e sarcoplasmática, decorrentes do ET pré-abate, através do índice de fragmentação miofibrilar (MFI), SDS-PAGE para troponina (SDS), imunodetecção de vinculina (IV) e força de cisalhamento (FC). Seiscentos frangos (Gallus gallus) foram abatidos em três dias diferentes (DA). Em cada DA os animais foram colocados em caixas de transporte (10 aves/caixa) e submetidos a ET (35ºC, 75 -85% UR)por 2 horas. Simultaneamente, o outro grupo de animais (NET) foi mantido em caixas em condição termoneutra (22ºC, 83 ± 6,6% UR) pelo mesmo período de tempo. Após o abate o músculo do peito foi coletado e mantido refrigerado, até a retirada de todas as amostras (0, 1, 2, 6 e 24 horas pós-abate

Effects of Varying Essential Oil Mixture Concentrations Applied Underconditions of Different Temperature Stress on Cardiac Markers and Other Blood Parameters

“…In another study, a higher value of troponin-T was determined as a result of stress caused by temperature differences (Maxwell, 1994;Maxwell et al, 1995;Maxwell et al, 1997;Aksit et al, 2008). A similar study on broilers showed that heat stress had a negative effect on specific myofibrillar fragments, which affected the level of troponin (Santos et al, 2008), heat stress applied to broiler stress and heart values have been determined to increase (Tekce & Gül, 2017). In our study, levels of cTnI were higherin the EOMtreated groups than in the control group, in groups not exposed to temperature stress (22ºC).…”

Pengaruh Perbedaan Suhu Pemeliharaan terhadap Kualitas Fisik Daging Ayam Broiler Periode Finisher

“…Umumnya, drip loss adalah proses berkelanjutan yang melibatkan transfer air dari miofibril dalam jaringan otot ke ruang ekstraseluler (Yu et al, 2009) Nkukwana et al (2015), bahwa denaturasi protein myofibrilar dan sarcoplasmic dapat mengakibatkan fungsionalitasnya hilang sehingga kemampuan protein untuk mengikat air berkurang, menghasilkan water holding capacity yang buruk dan memfasilitasi hilangnya konstituen sarcoplasmic yang larut dari sel otot ke ruang ekstraseluler, akibatnya meningkatkan drip yang keluar dari daging. Santos et al (2008) menemukan bahwa stres panas menyebabkan nilai WHC yang rendah karena hilangnya integritas membran akibat meningkatnya kreatin kinase dan jumlah hematokrit yang menurun. Sandercock et al (2001) dalam Brossi et al (2018, mengamati bahwa peningkatan aktivitas kreatin kinase menyebabkan nilai drip loss yang lebih tinggi pada dada ayam.…”

Effects of Farm Management Practices and Transport Time on Post-Mortem Changes of Longissimus lumborum Muscle Proteins in Suckling Goat Kids

“…Proteolysis of some myofibrillar components, such as Z line (α-actinin), as well as the degradation of regulatory proteins like troponin T and tropomyosin [ 3 ] are considered crucial for meat textural changes. Thereby, myofibrillar proteins (MFP) have been widely acknowledged as valuable indicators for estimating the extent of such changes throughout muscle ageing [ 4 ].…”