The relevance of biotechnology is certainly not restricted to the human domain, and rightly so, because over the ages man has not only been breeding animals but constantly trying to improve their traits using techniques such as cross breeding and artificial insemination.
Biotechnology when applied to animals focuses on livestock breeding and husbandry, nutrition and health, and the production of transgenic animals. Furthermore, animals play a dual role in furthering biotechnology; they benefit from better health and welfare on the one side, and on the other side help the cause of advancing research in human health.
Innovations in diagnostics have also played a part in better livestock breeding. Using biotechnology assisted diagnostics, animal parenthood can be instilled with certain physiological and biochemical traits that are deemed to be desirable. As preservation of endangered species of animals is an essential component of biodiversity conservation, biotechnology uses latest reproductive and cloning techniques to help preserve endangered species.
Animal reproductive biotechnologies have been around for quite some time although there are some advanced options of recent origin too. Let's take a look at some of the prominent ones, as producing more healthier livestock herds is a possibility using these techniques.
AI or artificial insemination using superior males is probably the first biotechnological method used to propogate farm animals. AI is widely practiced and allows better control and depth in the selection of males and facilitates easy transportation of frozen semen. AI was further refined using semen cryopreservation and synchronization of estrus and ovulation. This has facilitated breeding of cattle, sheep, goat and chicken.
This helps in better selection intensity of females, and in diploid genome conservation. Easy transfer of genetic material is facilitated by freezing of embryos.
Ovum pick-up (OPU) and in vitro maturation and fertilization (IVM/IVF)
Take the case of the water buffalo which is a source of sustenance for farmers especially in Asia in terms of providing milk, meat and hide. But this animal has a low reproductive rate. In water buffaloes the problem is inefficiency in in vivo embryo production on account of low ovulatory response. Biotechnology uses gamete manipulation techniques to address this problem by in vitro maturation and in vitro fertilization (IVM/IVF) in order to produce buffalo embryos.
Another method is aspiration of immature oocytes from live buffaloes. Those apart, high quality embryos can also be obtained in vitro from the oocytes of slaughtered buffaloes by follicular aspiration.
The success of in vitro technology, although limited by the low freezability of the embryos, depends on the donor status and the culturing technique used for getting the embryos pass from the stage of zygote to blastocyst. But one problem noticed is abnormalities in offspring.
Sexing of semen and embryos
Every cell of an embryo and the foetus of the animal contain a set of chromosomes (DNA that encodes 70,000 or so genes on the chromosomes typical for that animal). The male of that particular species of the animal has the Y chromosome which the females don't have, although cells of both males and females of the same animal species will have the same chromosomes and therefore the same genes. Embryo sexing involves finding out DNA sequences unique to the Y chromosome for separating the male, and the absence of it establishes the female. Separation techniques for embryo sexing can be done by using methods such as embryo biopsy, assay for Y chromosomal DNA, and Polymerase Chain Reaction.
Semen sexing involves using only the sperm containing Y chromosome to get males and using sperm with X chromosome to get females. Separation techniques for semen sexing can be done using Fluorescence Activated Cell Sorting and immunoseparation.
Actually cloning is a 1970s technology that is commonplace now.
Transferring a DNA fragment that is of specific interest from one organism to a bacterial plasmid (self-replicating extra-chromosomal circular DNA molecules) or a self-replicating genetic material (cloning vector) is called cloning or recombinant DNA technology. The intended DNA can then be propogated in a host cell
For example, Dolly was created by reproductive cloning technology using "somatic cell nuclear transfer" where genetic material from the nucleus of a donor adult cell was transferred to an egg whose nucleus (genetic material) had been removed. The reconstructed egg with the DNA from the donor cell was then suitably stimulated for cell division and the cloned embryo was then transferred to the uterus of a female for giving birth.
In short, the purpose of cloning in animals is to create an animal with the same DNA as one that had existed or currently exists.
It means creating animals that carry genes from other species or in other words the process of deliberate modification of a species genome--- and has been successfully carried out in cows, sheep, rabbits and other animals.
Transgenic animals are animals which have manipulated DNA, in that, an embryo could have a different gene from another source introduced into it to alter animal characteristics, as for example the creation of cattle for producing milk containing a specific protein, or containing less lactose or cholesterol; or for creating animals with a predisposition to certain diseases, in order to study those diseases and develop medicines; or for creating transgenic pigs to assist in providing organs for transplant purposes.
Transgenic animals can be made by three different methods namely DNA microinjection, retrovirus-mediated gene transfer, and embryonic stem cell-mediated gene transfer
In the poultry sector which exhibits high reproduction as well as increased quantity of short lived individuals, the use of biotechnology in treatment or diagnostics is not considered important. On the contrary transgenic animals are the in thing here although consumer acceptance is sometimes an issue.
Diagnostic tests of biotechnological origin help in finding disease causing agents in animals and to precision monitor disease control programs to the level of sub-species, strain etc as for example automated Enzyme Immuno Assay are available to detect different parasites and microbes
When epidemic diseases strike animal populations it is important to track their origin for effective disease control. This is possible by using techniques of molecular epidemiology such as nucleotide sequencing
There are several medicines for use in animal health that can be attributed to biotechnology. Vaccines against ticks and helminths are possible (parasites) using recombinant DNA technology and conventional vaccines have not been successful here. Using the same technology, recombinant vaccines can be used to treat livestock suffering from viral, mycoplasmal and bacterial diseases. These vaccines have better specificity, stability and better safety parameters.
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