A pet dog without ticks is a promise that biotechnology can deliver. However, going beyond such ‘designer animals’, the technology can achieve lots in the field of livestock. Not much is being done, given the ethical questions and need for regulations. The life and death of Dolly was a blow to the hype.

But, biotechnology goes beyond cloning. It can be used to ‘farm’ animals for human therepeutics, genetically modify forage crops, create transgenics that allow the required traits to be ‘planted’ in the species, etc.

A recent symposium in Bangalore saw experts discuss the emerging technologies in the field of animal biotechnology. It was organised by Association of Biotech Led Enterprises and National Institute of Animal Nutrition.

“You can use livestock for human therepeutics, without harming the animal,” said S Krishnaswamy, an entrepreneur who has his biotech company that is working in this area. By introducing a gene into the hen, it is possible to produce antibodies against bacterial infections that affect the human system. His company Animal Biotech is working on this, he said.

This is much cheaper and beneficial than using antibiotics. The economics of production is in favour of chicken models rather than other animals, he feels. Chickens are excellent producers on antibodies and the intensity of their immune response is comparable to mammals, besides being fast. The IgY or the serum immunoglobin can be obtained from chicken in large quantities too. Every day the hen can lay an egg with 50-100 mg of IgY. Twelve eggs contain one gram of IgY antibodies which is what is the amount present in 100 ml of serum. One hen can substitute up to 12 rabbits in antibody production!

These would cause no allergic problems in mammals too, he said.

Insulin was originally obtained from pigs but now with the human gene inserted into a yeast, the same can be obtained from a egg. Antithrombin 3 used as an anticoagulant in coronary surgery can be obtained from goat’s milk using genetic modification. So also many drugs like antitryspin (for cystic fibrosis), lacto ferrin (from cow, and used to treat mastitis), etc.

By introducing a human gene into the cow, it can be made to produce human growth factor when fed with zinc. This, as Krishnaswamy notes, is cheaper than maintaining fermentors.

However, as Prof G Padmanabhan observed, many of these have been showed to work at the lab level but none commercialised. How are people going to accept hormones grown in animals? It is because of this that biotechnology has shifted to plants. But even then, there is a demand to purify the protein outside once it is expressed in the plant, and not used straight from the plants.

But with demand threatening to outstrip supply, whether it be for milk, eggs or meat, there is a clear need to get more from limited sources. Improving the nutrients in animal feed, optimising the feed conversion ratio, modulating the animal immune system to increase disease resistance are some areas of research.

Improving fodder

In India, the Indian Veterinary Research Institutes, NIANP, and several other institutions (a total of 19, besides the universities) are working on various issues. For instance, at NIANP research is on about increasing the digestability of fodder.

Agricultural crop residues like wheat straw, etc are rich in lignocellulose and constitute livestock feed. Almost 60-70 percent of these residues are made up of cellulose or hemicellulose which are good sources of energy. But lignin acts as a barrier between cellulose and the microbes that break it down in the animal’s digestive system. Also, the presence of anti-nutritional factors like silica do not allow the animal to extract this in full.
How to remove the lignin and factors like silica is part of the study.

At IVRI, Izzatnagar, study has narrowed onto a group of microorganism called the white rot fungi that has a affinity for lignocellulosic feeds and help degrade lignin.

Bacteria populations

The NIANP team is also looking at ways to increase the population of microorganisms through genetic modification method. The genes that encode for the enzymes that help in the breaking down process is introduced into the bacteria within the animal. In their study they isolated a cellulosic gene from Orpinomyces spp and cloned it into Escherichia coli. The next step is the transfer of the gene encoding for exocelluloses into the rumen bacteria.

Bacteria and their genes are also being employed to degrade toxins in the environment which could otherwise find their way into the animals. Detoxifying pesticide remnants and reducing their absorption by the animals in a field NIANP is looking at.

Mineral deficiency in the feed is often not easily identified. Using biochemical markers (enzymes) whose estimation gives an idea of the presence of minerals is a topic of study. NIANP is in the process of developing such a kit, said the director K T Sampath.

Development of novel vaccines could be the most productive field where biotechnology can contribute and India can lead. DNA vaccines have shown hope but as experts say they are “notoriously poor in field conditions”. Whether it be live attentuated or killed mode, the present vaccines have shortcomings. The live could revert to virulence while the killed vaccines may not impart long term immunity.

Virus like particle (VLP) technology is being studied where the VLPs are similar to the virus but lack the viral genome and are safe. Plant vaccines are also being looked at.

With sectors like aquaculture poised to reap $40 billion through exports by 2015, there is need to address the problems faced in tackling diseases, feed, etc. Biotechnology can help, say the experts.