UTILITY OF TRANSGENIC ANIMAL IN FOOD INDUSTRY

UTILITY OF TRANSGENIC ANIMAL IN FOOD INDUSTRY

Anusmita Baishya¹, Inzamul Alam², Hitesh K Bagri³ and Nadeem Shah⁴

¹PhD Scholar (Livestock Production and Management)

²MVSc Scholar (Livestock Production and Management)

³MVSc Scholar (Animal Reproduction, Gynaecology and Obstetrics)

⁴PhD Scholar (Animal Reproduction, Gynaecology and Obstetrics)

ICAR-National Dairy Research Institute (NDRI), Karnal-132011 (Haryana) India

*anusmitabaishya@gmail.com

Abstract:

Animals with an altered genome are known as transgenic animals and it is used to improve the target animal’s genetic features. For improvement of food industry and by products of livestock industry and to compete with the increasing population there is need to promote utility of transgenic animals. Transgenic animals can also be helpful in laboratory as models in biomedical research. They can be important tools for researching human disease, being used to understand gene function in the context of disease susceptibility, progression and to determine responses to a therapeutic intervention. The different types of transgenic animals and the methods used to make transgenic milk and meat are outlined in this article, as well as the benefits and downsides of using them.

Introduction:

The United States Food and Drug Administration (FDA, 2018) published an article stating that “meat and milk from clones of cattle, pigs, goats, and the offspring of clones from any species traditionally consumed as food, are as safe to eat as food from conventionally bred animals”.

Transgenic animals:

1. Superfish: To increased growth size. Growth hormone gene inserted into fertilized egg. Transgenic salmon grows about 10-11 times faster than normal fish.
2. Glo fish: GM freshwater zebra fish (Danio rerio). It is produced by integrating a fluorescent protein gene from jelly fish into embryo of fish.
3. Alzheimer’s mouse: In the brain of alzheimer’s patients, dead nerve cells are entangled in a protein called amyloid. Mouse made by introducing amyloid precursor gene into fertilized egg of mice.
4. Oncomouse: Mouse model to study cancer, made by inserting activated oncogenes.
5. Smart mouse: Biological model engineered to overexpress NR2B receptor in the synaptic pathway. This makes the mice learn faster like juveniles throughout their lives.
6. Enviro pig: Pigs have trouble fully digesting a compound known as phytate found in many cereal grains used to feed them. Transgenic pigs are created by introducing phytase gene of E. coli. Phytase enzyme is thus produced in the salivary gland of pig. It degrades indigestible phytate with the release of phosphate that is readily digested by pigs.
7. Transgenic cattle: Transgenic cows are made to produce proteins lactoferrin and interferon in their milk. Prion free cow’s resistant to mad cow disease
8. Transgenic sheep: For good quality of wool production.
9. Transgenic goat: Goats that could express tissue plasminogen activator, anti-thrombin III, and spider silk etc in milk.
10. Transgenic rabbit: Alba, the EGFP (Enhanced Green Fluorescent protein) bunny. Created in 2000 as a transgenic artwork.
11. Transgenic monkey: ANDi was the first transgenic monkey, born in 2000. ANDi stands for inserted DNA spelled backwards. An engineered virus was used to insert the harmless gene for green fluorescence protein (GFP) into ANDi’s rhesus genome. ANDi proves that transgenic primates can be created, and can express a foreign gene delivered into their genome.

Transgenic cattle:

Transgenic cattle produce lactoferrin and interferons. Myostatin gene is used for double muscling in cattle. Transgenic cattle containing two extra copies of kappa casein increase the 13% more proteins. Lactose-free milk (transgene lactase) has been produced.

Production of transgenic milk:

Transgenic milk can be prepared by two ways. One way is by inserting an extra gene into cow embryos, modifying their genetic make-up. Another method is to mate ‘normal’ cows with genetically modified bulls so that the next generation of calves will produce the desired protein. A gene from a bacterium will not often work correctly if it is introduced unmodified into a eukaryotic animal cell. The genetic engineer first of all constructs a transgene containing the gene of interest plus some extra DNA that correctly controls the function of the gene in the new animal. This transgene has then to be inserted into a new animal. Many genes are only expressed in particular tissues and are controlled by special segment of DNA next to the gene called promoter sequence. When constructing a transgene, scientists generally substitute the donor’s promoter sequence with one that is specially designed to ensure that the gene will function in the correct tissues of the recipient animal. This is crucial when, for example the gene need to be expressed in milk of animal.

Usefulness and application of transgenic milk:

• Milk-producing transgenic animals are especially useful for production of medicines, nutritional supplements and pharmaceuticals.
• Products such as insulin, growth hormone, and blood anti-clotting factors have already been obtained from the milk of transgenic cows, sheep, or goats.
• Research is also underway to manufacture milk through transgenesis for treatment of debilitating diseases such as phenylketonuria (PKU), hereditary emphysema, and cystic fibrosis.
• This transgenic milk is a more nutritionally balanced product than natural bovine milk and could be given to babies or the elderly with special nutritional or digestive needs.
• Argentinean scientists have developed a cow which can secrete human insulin in its milk. This insulin will be purified from cow milk and used for treatment of Diabetes Mellitus.
• Clinical applications of antibodies often require large amounts of highly purified molecules, sometimes for multiple treatments. The development of very efficient expression systems is essential to the full exploitation of the antibody technology. Production of recombinant protein in the milk of transgenic dairy animals is currently being tested as an alternative to plasma fractionation for the manufacture of a number of blood factors (human antithrombin, human alpha-1-antitrypsin, human serum albumin, factor IX). The ability to routinely yield mg/ml levels of antibodies and the scale-up flexibility make transgenic production an attractive alternative to mammalian cell culture as a source of large quantities of biotherapeutics.

Disadvantages of transgenic milk:

• The transgenic milk produce by rBGH contains elevated levels of IGF. These include: reduction in short-chain fatty acid and increase in long-chain fatty acid levels, posing cardiovascular risks; increase in levels of a thyroid hormone enzyme; frequency of pus cells in milk due to mastitis; and contamination of milk with unapproved drugs fortreating mastitis. IGF-1 is a protein fraction known as a peptide. As such, it survives digestion and is readily absorbed into the blood. Most importantly, increased IGF-1 levels have been reported to increase risks of breast cancer by seven times in 19 scientific publications, colon cancer by five times in 19 publications, and prostate cancer by up to 5 percent in six publications.
• Cultured meat production:

Meat produced from cell cultures is a prominent alternative for traditional meat derived from live animals. This approach gained increasing attention in public opinion, popular media, animal welfare organizations, the scientific community, and among investors, particularly after the production of the first clean meat prototype.The biotechnological approach, which broadly includes cell and tissue culture, they are also popularly known in the jargon of biotechnology as ‘Scaffold based’ and ‘Self-organizing techniques’.

1. Self-organizing technique: The first method involves using an explant from a donor animal’s muscle, which is then multiplied in a nutrient medium. The origins of the term can be traced back to the early 21st century when tissueengineering methods were used to grow meat. They placed skeletal muscle explants from goldfish (Carassiusauratus) in diverse culture media and observed a varied pattern of growth, concerning an increase in surface area over 7 days. The results based on the medium were as – fetal bovine serum: 13.8%, fish meal extract: 7.1%, shiitake extract: 4.8%, maitake extract: 15.6%. Explants were also put in a culture of dissociated Carassius skeletal muscle cells, which resulted in a 79 percent increase in the explant surface region. The self-organizing technique helps to create structured meat i.e. meat produced will have a well-defined 3-D structure, just as the natural conformation of meat. The same can be achieved using the principles of tissue engineering for de novo synthesis of muscle tissue.

2. Scaffold-based technique: The second method of culturing meat involves suitable stem cells which can be obtained from a variety of tissues. The scaffold-based technique involves proliferating embryonic myoblasts or adult skeletal muscle satellite cells, adding them to a scaffold or carrier, and then perfusing them with a culture medium in a bioreactor. The scaffold-based technique operates on the concept of appropriate muscle cells proliferating on a scaffold in the presence of a culture medium in a bioreactor. Myofibers are produced as a result of this culturing, which can then be harvested, processed, and consumed as meat or meat products.

• Fate of transgenic animal:
• Improving food quality or making novel food products
  Improving the quantity or quality of the milk or meat from cows may be of value. For example, milk with extra casein requires less processing to make into cheese and will have increased calcium levels.
• Transgenic technologies could be used to improve animal health by increasing resistanceto diseases. For example, transgenic dairy cows expressing lysostaphin (an antimicrobial) in their milk show greater resistance to mastitis-causing bacteria  aureus. Mastitis is a common bacterial infection that can lead to severe health problems in cows.
• Farming has a big impact on our environment. Transgenic animals may offer one way of reducing the environmental impact by improving farming efficiencies and reducing pollution. An example is the Enviropig™. These transgenic pigs have an additional gene that helps them digest plant material. This lessens their need for dietary supplements and reduces environmental pollution.

Conclusion: 

Other than breeding, transgenesis is a revolutionary tool which form a totally different strain. It holds a great potential in many different fields like agriculture, medicine and food industry. Boosting of transgenic products will certainly help in coping with increased population.

References:

https://www.pashudhanpraharee.com/importance-of-transgenic-animals/

Pollock, D. P., Kutzko, J. P., Birck-Wilson, E., Williams, J. L., Echelard, Y. and Meade, H. M. (1999). Transgenic milk as a method for the production of recombinant antibodies. Journal of immunological methods, 231(1-2), 147-157.

Shah, N., Sethi, M., Yadav, D. K., Kumar, P., Soe, A., Nath, S. Bhakat, M. and Mohanty, T. K. (2021). Biotechnological potential of stem cells in food-producing animals: A review. Indian Journal of Animal Health, 60(1), 01-09.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3612824/

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