Biotechnology in animal nutrition, physiology and health

Development and application of modern agricultural biotechnology in Botswana: the potentials, opportunities and challenges

In Botswana, approximately 40% of the population live in rural areas and derive most of their livelihood from agriculture by keeping livestock and practising arable farming. Due to the nature of their farming practises livestock and crops are exposed to diseases and environmental stresses. These challenges offer opportunities for application of biotechnology to develop adaptable materials to the country's environment. On the other hand, the perceived risk of genetically modified organisms (GMOs) has dimmed the promise of the technology for its application in agriculture. This calls for a holistic approach to the application of biotechnology to address issues of biosafety of GMOs. We have therefore assessed the potentials, challenges and opportunities to apply biotechnology with specific emphasis on agriculture, taking cognisance of requirement for its research, development and application in research and teaching institutions. In order to achieve this, resource availability, infrastructure, human and laboratory requirements were analyzed. The analysis revealed that the country has the capacity to carry out research in biotechnology in the development and production of genetically modified crops for food and fodder crops. These will include gene discovery, genetic transformation and development of systems to comply with the world regulatory framework on biosafety. In view of the challenges facing the country in agriculture, first generation biotech crops could be released for production. Novel GM products for development may include disease diagnosis kits, animal disease vaccines, and nutrient use efficiency, drought, and pest and disease resistant food and fodder crops.

Position of the American Dietetic Association: Agricultural and Food Biotechnology

It is the position of the American Dietetic Association that agricultural and food biotechnology techniques can enhance the quality, safety, nutritional value, and variety of food available for human consumption and increase the efficiency of food production, food processing, food distribution, and environmental and waste management. The American Dietetic Association encourages the government, food manufacturers, food commodity groups, and qualified food and nutrition professionals to work together to inform consumers about this new technology and encourage the availability of these products in the marketplace.

Cloning, characterization, and expression studies in Escherichia coli of growth hormone cDNAs from Indian zebu cattle, reverine buffalo, and beetal goat

The growth hormone cDNAs from three different economically important animal species of indian origin viz., indian zebu cattle (Bos indicus), indian reverine buffalo (Bubalus bubalis), and beetal goat (Capra hircus) were isolated by the RT-PCR technique. The amplified product was then cloned into phagemid pBluescriptIIKS- and the nucleotide sequence of the entire 573 base coding region for each product was determined. The genetic sequences as well as the translated protein sequence of these ruminant species were compared to that of closely related species like taurine cattle (Bos taurus) and sheep (Ovis aries). A very high degree of nucleotide sequence homology, ranging between 97-98%, was observed. Subsequently, the buffalo and goat cDNAs were used for expression studies in Escherichia coli. Very low levels of expression resulted when the growth hormone cDNAs were directly placed under the strong E. coli (trc) or phage (T7) promoters with the approximate level being less than 0.1% and 1% of the intracellular E. coli proteins, respectively. The nearly 10-fold enhancement of the level of expression as observed was attributable to the nature of the untranslated leader sequence donated by the individual expression element. High level (about 20% of soluble E. coli protein) expression of buffalo/goat growth hormone was achieved as a fusion protein with glutathione-s-transferase (GST) in pGEX-KT. Further, although attempts at converting the GST-GH fusion protein system to a two-cistronic gene expression system were unsuccessful, the utilization of a short synthetic first cistron in the two-cistronic mode of expression resulted in high levels (approximately 30% of soluble protein cell fraction) of GH polypeptide with a native N-terminus in E. coli for all three cDNAs.

Production of recombinant buffalo (Bubalus bubalis) and goat (Capra hircus) growth hormones from genetically modified E. coli strains

The growth hormone cDNAs of Indian reverine buffalo (Bubalus bubalis) and beetal goat (Capra hircus) were cloned in Escherichia coli through RT-PCR technique. Nucleotide sequencing revealed several silent mutations in both cDNAs and only one amino acid change in the case of goat when compared to reported bovine (Bos taurus) sequence. The high level expression of both the polypeptide hormones was achieved in E. coli (> or =30% of soluble intracellular proteins) through the construction of two-cistronic gene expression system. The solubilisation of recombinant growth hormones from inclusion bodies and subsequent oxidation to correctly folded monomeric form was also carried out. A combination of reverse-phase HPLC and non-reducing SDS-PAGE was successfully applied to distinguish between reduced and oxidised forms of growth hormones. A moderate yield ( approximately 40% of starting material, with potential for upscaling), two-step purification process comprising of hydrophobic interaction and ion-exchange chromatographies was developed. The process eliminates the need for costly, laborious and time-consuming steps of ultrafiltration and dialysis, as reported earlier for the purification of many recombinant animal growth hormones. The biophysical, biochemical and functional analyses of purified refolded polypeptides showed that the hormones produced in this study were identical to natural pituitary bovine growth hormone.