Over Expression of Voltage Dependent Anion Channel 2 (VDAC2) in Muscles of Electrically Stunned Chickens

Abstract

Water bath stunning is a common practice in commercial slaughterhouses. Such treatment is economic and in line with animal welfare practice. However, the conditions applied for the stunning process may vary from a slaughterhouse to another slaughterhouse. Such a loose regulation on the stunning procedure has opened up doors for food adulteration such as over dose stunning. In this study, a simple and reliable approach using proteomics have been developed to study the effect of different currents and voltages in stunning on the protein expression of the chickens. Protein profiles of the chickens were constructed in order to detect any differences in protein expression and modifications. The different voltage studied were 10 V, 40 V and 70 V while the values for current studied were 0.25 A, 0.5 A, and 0.75 A. After the proteomics analyses using 2D Platinum ImageMaster 6.0 and Matrix-assisted laser desorption ionization- time of flight (MALDI TOF) spectrometry identification, Voltage dependent anion channel 2 (VDAC2) was identified to be over expressed in the muscle sample of over stunned chicken. The over expression of VDAC2 was confirmed at the transcriptional level of RNA expression. Real Time PCR showed that all over stunned samples contained higher mRNA expression level for VDAC2 genes. The mRNA level of VDAC2 was up-regulated by 59.87 fold change when normalized with housekeeping gene. In conclusion, VDAC2 could serve as potential biomarkers for identification of electrically stimulated chickens. The existence of these biomarkers will help to monitor the slaughtering and stunning process in the future. It will revolutionize the food authentication field and give a new breathe to the meat industry.

ABSTRAK: Kaedah "waterbath stunning" merupakan amalan biasa di pusat-pusat penyembelihan. Kaedah ini adalah ekonomik dan selari dengan amalan kebajikan haiwan. Walaubagaimanapun, syarat-syarat yang digunakan untuk proses kejutan tersebut mungkin berbeza antara sebuah pusat sembelihan dengan pusat sembelihan yang lain. Sebarang peraturan yang longgar semasa proses kejutan tersebut membuka ruang kepada adulterasi makanan seperti lebihan dos kejutan elektrik. Dalam kajian ini, satu pendekatan yang mudah dan boleh dipercayai menggunakan proteomik telah dibangunkan untuk mengkaji kesan arus dan voltan yang berbeza dalam proses kejutan elektrik terhadap ekspresi protin di dalam ayam. Profil protein ayam telah dibuat untuk mengesan sebarang perbezaan terhadap ekspresi dan modifikasi protin. Nilai voltan berbeza yang dikaji ialah 10 V, 40 V dan 70 V manakala nilai arus yang dikaji 0.25 A, 0.5 A, dan 0.75 A. Selepas analisis proteomik menggunakan Platinum 2D ImageMaster 6.0 dan Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI TOF) Spectrometry Identification, Voltage Dependent Anion Channel 2 (VDAC2) dikenal pasti terlebih ekspres di dalam sampel otot ayam yang terlebih dos kejutan elektrik. Lebihan ekspresi VDAC2 disahkan di peringkat transkripsi ekspresi RNA. Real Time PCR menunjukkan bahawa kesemua sampel yang terlebih dos kejutan mengandungi tahap ekspresi mRNA yang lebih tinggi di dalam gen VDAC2. Tahap mRNA VDAC2 dikawal oleh 59.87 perubahan kali ganda apabila dinormalkan dengan gen housekeeping. Kesimpulannya, VDAC2 boleh bertindak sebagai penanda biologi yang berpotensi untuk mengenal pasti ayam yang dirangsang elektrik. Kewujudan penanda biologi ini akan membantu memantau proses penyembelihan dan kejutan pada masa akan datang. Ia akan merevolusikan bidang pengesahan makanan dan memberi nafas baru kepada industri daging.

Keywords
Stunning, Slaughtering, Proteomics, Voltage dependent anion channel 2, Chicken muscle