Determining the amount of some microRNAs that are effective on human health in different animal milks and investigating the effects of different heat treatments on these microRNAs

Aim: In this thesis, the presence of miRNA 15a, miRNA 29b, miRNA 34a and miRNA 223 in cow, buffalo, sheep, goat and donkey milk, their expression levels and their relationship with milk composition were investigated. In addition, the change levels of these miRNAs were examined by applying different temperatures to the milk. Materials and Methods: In the study, physicochemical analyzes of cow, buffalo, sheep, goat and donkey milk were performed. RNAs were obtained by isolating the exosomes of milk. The expression levels of miRNA 15a, miRNA 29b, miRNA 34a and miRNA 223 were obtained in the RT-qPCR device, and correlation analysis was performed between the physicochemical data of milk and the data of miRNAs. By applying different temperatures to the milk in the oil bath, the changes in the amount of four miRNAs in the milk were determined. Results: In the analysis, it was determined that miRNA 15a, miRNA 29b, miRNA 34a and miRNA 223 were expressed in all milks. A positive and significant relationship was found between miRNA 34a and fat in cow's milk. A positive and significant relationship was found between miRNA 34a and pH dry matter in sheep milk. A negative and significant relationship was found between miRNA 29b and dry matter and fat in sheep milk. A positive and significant relationship was found between miRNA 223 and dry matter in goat milk. A positive and significant relationship was found between miRNA 29b and fat in donkey milk. In addition, it was determined that miRNAs were affected by heat with different heat-related changes in miRNAs. 4 Conclusion: In the milk of all examined animal species, the expressions of the investigated miRNAs and their significant relationship with the composition of the milk were determined. It was observed that miRNAs gave different responses when heat treatment was applied to milk. It is thought that miRNAs are important study areas in terms of milk health, hygiene, composition and technology, and more specific and detailed studies should be planned on these issues. Key Words: MicroRNA, Milk, Donkey milk, Extracellular vesicles, Exosome