OmicsintheFieldofPhysiology

Omics is a science branch that aims to characterise and quantify many biological molecules that decode into an organism’s structure, function, and dynamics. Before understanding the purpose of Omics and different Omics technologies and their functional capability in physiology, let us look at the mega human genome project, the starting point for Omics.

The Human Genome Project was a massive undertaking involving scientists worldwide working together to decipher the deoxyribonucleic acid (DNA) sequences that make up the human genome. The project began in 1990 and was finished in 2003, 2 years ahead of schedule. Researchers decrypted the mystery of DNA. According to them, the genome of every person on earth is 99.9% the same. It is that tiny 0.01% that makes up genes that give us our unique differences. An essential aspect of the human genome project is to identify any mutation in a gene order that could lead to disease. Scientists can use this information to extrapolate the genetic causes of diseases and develop treatments for the variants of genes or alleles associated with various inherited disorders. Genetic tests can be performed on individuals to determine whether they are carriers or sufferers of an inherited disorder. It took 13 years and billions of dollars to sequence the whole genome during the human genome project, but now researchers can do it in a few hours and for a relatively low charge.

Animal researchers have the same goals of identifying gene variants that add to good health and further increase the food production capacity and quantity of animal products. Much of the match for functional gene annotation for animal sequences comes from human orthologues. Even though advances are made in physiology and allied sciences; however, full potential has been not achieved in Omics work, for instance, Sire-based evolution using genomics for future productive offspring production.

Through a wide range of Omics techniques, it is possible to get insight into an animal’s sensory system and surroundings. For instance, pufferfish, when exposed to cold stress, more than 5000 differentially expressed genes (DEG) popped up. Further, only a few differences were in proteins and metabolites. This study reflects the importance of different Omics approaches. If only transcriptomic data were be considered, it might not have reflected proteins and metabolites at a single stretch. However, when proteomics and metabolomics were combined, it gave the network analysis. It revealed that different molecular interactions were associated with immunity, metabolism of fatty acids, transport of bile salts, and lipolysis, suggesting that these processes were essential for pufferfish to withstand cold stress. This study can be the best example to weigh the multi-Omics approaches in the field of physiology.

We search for robust breeds in different species to fulfil the global food demand in this present climate change. Heat stress and nutrition stress are the major abiotic stressors for dairy cattle. Although Omics science has advanced, heat stress’s direct and indirect impacts remain key obstacles in understanding the interaction between genetic polymorphism, genes, transcripts, proteins, and metabolic pathways connected to productive qualities like milk and meat output. To give a better perspective, let us imagine cattle is subjected to multiple stressors (thermal, nutritional, and walking stress). In response to the stress, the homeostatic mechanism triggers to counteract those stressors in cattle. It can be quantified using genomics, which identifies the genes, SNPs associated with stress resilience via genome-wide association studies (GWAS).

Further, epigenome studies propel us to the identification of DNA modifications that change accessibility for transcription. A transcriptomic study allows the quantification of the mRNA (gene transcripts) in different tissues in response to stress response (Fig.

1.8). It can be cross verified through proteome, examining the entire set of proteins after translation from mRNA and post-transcriptional modifications. Additionally, metabolomics gives us an idea about lipids, water-soluble and volatile molecules formed after protein

Fig. 1.8 Pig is exposed to an increase in temperature and each level transcriptomic response is recorded. Transcriptomic changes are made to improve the individual’s response to heat stress. As the temperature increases, transcriptomic adjustments are made such that animal gets acclimatised to the changing environment through changes in their physiological modifications by animals. (Courtesy: BioRender)

and enzyme activity occur or formed because of these reactions.

Another area of interest for many researchers is the complex relationship between ruminants and rumen-dwelling microbiota. Based on sequencing target regions of the 16S rRNA gene, the characterisation of rumen microbiota can be done. It enables us to characterise the microorganisms and their functional contributions to the host’s energy production. Nevertheless, this process will not fetch information about their functionality. However, multi-Omics science such as metagenomics, transcriptomics, metaproteomics, and metabolomics provides deeper comprehension of the ecology of rumen microbiomes, the symbiotic host-microbe relationship, and the impact of different nutritional factors manipulations on the productivity of animals. Metagenomics enables the assessment of the microbiome’s diversity and potential functional capacity, whereas metatranscriptomics can shed light on the microbiome’s actual function via gene expression. Metaproteomics and metabolomics, when used together with metatranscriptomics, can aid in identifying the members of an active microbial community. Additionally, they give information on differentially expressed metabolic pathways by utilising NMR or MS-based approaches to access the proteins expressed and metabolites generated.

While next-generation sequencing and functional metagenomics are being used to study the rumen microbiome in tropical animals, integrating the results with other meta- Omics remains a challenge.

Learning Outcomes

• With the basic understanding of a complex yet unique bunch of living units—cells combined with recent developments, one can anticipate the future with agricultural and biomedical applications such as the production of genetically engineered animals.

• A better comprehension of the integration system includes the nervous and endocrine systems, which are primarily responsible for maintaining the animal’s metabolic homeostasis. Signals from neurons are precisely targeted, but signals produced from the endocrine gland are broad-spectrum signals distributed throughout the animal’s body. Coordination of both chemical and electrical systems is critical for maintaining balance within the animal.

• Exchange and transport systems, i.e. respiratory system and circulatory system, work together to supply cells and tissues with the necessary oxygen and metabolites so that they can operate optimally.

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Q8. Major excretory product in birds is

• Kidneys act as a regulator of plasma with various functions like regulating pH, osmoregulation, and filtration of nitrogenous waste and metabolic waste products as a means of achieving homeostasis either naturally or through technological advancements.

• Deeper insights into various reproductive structures present in different types of animals, the role of hormones in gametogenesis, ovulation, and implantation and most importantly, various assisted reproductive technologies to meet global food demand.

• To appreciate the physiological mechanisms controlling the growth and development of the mammary gland—factors influencing milk secretion. To acknowledge recent developments in the field of the genetically engineered mammary gland.

• Influence of environment on various metabolic activities in animals.

Causes of climate change and its impact on animal adaptation and effect of multiple stressors on animal productivity. General mechanism of thermoregulation in adapted animals.

• Basics and history of the human genome project. The advantage of multi-Omics research to increase animal productivity in this present climate change situation.

Exercises

Objective Questions

Q1. The average size of cells is____________________.

Q2. The animal nervous system is capable of a wide range of functions. The basic unit of the nervous system is

Q3. How do neurons communicate with one another?

Q4. Which is the primary glucocorticoid produced in the ruminants?

Q5. Thyroxin is responsible for____________________.

Q6. Cells absorbs oxygen through___________________.

Q7. Pigment responsible for blue blood colour in octopus is

Q9. Give some examples of assisted reproductive technology.

Q10. Mammary gland is derived from the layer during embryonic stage.

Q11. Profuse sweating animal other than human is

Q12. Human genome project started in the year

Answer to Objective Questions

A1. 0.01-0.1 mm

A2. Neurons

A3. Electrically and chemically

A4. Cortisol

A5. Promoting the growth of tissues in the body

A6. Diffusion

A7. Haemocyanin

A8. Uric acid

A9. Sperm sexing, embryo transfer, and artificial

insemination

A10. Ectoderm

A11. Horse

A12. 1990

Acknowledgement The figures in this chapter are created with BioRender.com and therefore the authors express their sincere gratitude for BioRender organisation for helping to create figures using their resources. The authors also thankful to the Director, National institute of Animal Nutrition and Physiology for providing necessary permission to contribute this chapter.

OmicsintheFieldofPhysiology

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