Bioactive potential of yak's milk and its products; pathophysiological and molecular role as an immune booster in antibiotic resistance

Highlights

• Antibiotic resistance is a big threat due to decrease of antibiotics effectiveness.

• Yak's milk triggers the changes in gene expression of resistant bacterial strains.

• 7-h hydrolysate casein helps to scavenge DPPH that strengthens the immune system.

• GlyCAM1 has an immense diversity in antibacterial and immune-protective responses.

• Proteose peptone 3, β-carboline, MFGE8 are affective against different resistant strains.

Abstract

Antibiotic resistance is one of the most serious health threats in the world. The emergence of resistant bacteria has seriously limited our ability to treat bacterial illness. So, the world is moving toward other ways of treatment. Scientists emphasis on nutrition to maintain human health to overcome such problems. Yak's milk is rich in bioactive constituents with an antagonistic activity that triggers the changes in gene expression of bacteria. Therefore, it is imperative to present a comprehensive review of the bioactive potential of yak's milk against antibiotic resistance on pathophysiological and molecular grounds. The development of resistance occurs due to a variety of mechanisms and the number of resistant mechanisms inside the microbes. Over time, this new molecular-based resistance has been progressively disclosed. Yak's milk has many bioactive compounds, e.g. 7-h hydrolysate casein, MUC-1, butyrophilin, and Glycosylation-dependent cell adhesion molecule 1. The availability of these compounds makes it the right choice regarding immense diversity in antibacterial and immune-protective responses. By keeping in view the pathophysiological and molecular aspects of yak's milk, multifactorial and coordinated measures may be taken to counter the challenge of rapidly increasing antibiotic resistance. The present review article provides information on the recent findings regarding the biochemical and physiological actions of yak's milk against different bacterial strains and in the strengthening of the immune system. However, limited information on the genomic structure and industrialisation are some fundamental challenges to be tackled for effective drug formulations by pharmaceutical companies through yak's bio-actives.

Introduction

Bacterial infections are responsible for the loss of several thousand lives and the economy across the globe. Most common infections, such as urinary tract infections, bloodstream infections, and pneumonia, have obtained a position where standard treatment is readily available in most parts of the world (Organization, 2014). Modern medical procedures are also facing such challenges due to the evolution in genes of microbes. Enormous pathogenic bacteria have been classified as creating severe and concerning threats by the Centers for Disease Control and Prevention (CDC) in the form of a substantial clinical burden on the health care system, patients, and their families (Ventola, 2015). Researchers throughout the world investigated such a growing burden of antibiotic resistance by moving toward alternatives of antibiotics (Ventola, 2015). Therefore, a new class of useful antibiotic alternatives is always expected to be developed.

Yak is a unique bovine subfamily that is mainly inhabitant at low temperatures (−40 °C), low oxygen content, and high pressure (550 hPa) in the Qinghai Sino-Tibetan region of China (Li et al., 2019; Nikkhah, 2011) and Hindu Kush Himalayan region of neighbouring countries such as Pakistan, India, Nepal, Bhutan, and Afghanistan. According to estimation, the total yak population in the world is approximately 14.2 million. In which 13 million of the total population is an inhabitant in China (Nikkhah, 2011). Tibetan nomads have been using yak's milk for many years. According to some reports, Tibetan nomads do not eat fruits and vegetables for almost eight months or a year due to the availability concern. However, there is no deficiency of vitamins and minerals or any sign of chronic illness (Guo et al., 2014). This raises the question that, how Tibetans can stay healthy in such extreme stressful conditions with such a simple diet. A vital role is likely being played by yak dairy products in their lives. So, there is an increasing focus on a diet as a tool to maintain human health in different diseases (Bennett et al., 2015). Yak's milk is rich in functional and bioactive compounds. These compounds play an essential role in maintaining health status against different diseases (Guo et al., 2014). This uniqueness of milk is due to its detailed profiling of amino acids, fatty acids, antioxidants, vitamins, enzymes, and higher content of polyunsaturated fatty acid (PUFA) and conjugated linoleic acid (CLA) (Nikkhah, 2011). The biological role of specific PUFA has recently attracted more attention to improving the fatty acid profiling of food at the industrial level. Many studies have also focused on CLA and its isomers, because of their potential benefits such as antidiabetic, anticarcinogenic, and innate immunity enhancer against pathogens (Liu et al., 2011; Pariza et al., 2001). Also, scientific research has confirmed that there are numerous probiotic strains in yak's milk and its products, that have antibacterial activity (Zhang et al., 2016). Lactobacillus strains are the largest and dominant among all these strains. These bacterial strains have mostly protective function against microbial pathogens by producing bacteriocins, as well as creating competition for nutrients and attachment to the microbiota, that enhances the immune system of the body (Yousefi et al., 2019). Increased attention has been paid to the Yak's milk bioactive constituents and their immunoregulatory essays with future prospective. The current review summarises yak's milk potential against pathogens and its direct and indirect influence to overcome antibiotic-resistant bacteria.