Biotechnological Approaches for Enhancing Animal Health and Production

Abstract

global increase in the demand of livestock products, numerous attempts are being made to enhance the animal productivity and health. Among the various approaches, biotechnological approaches which are briefly summed up here offer promise to enhance livestock health and production. Improvement of livestock has traditionally focused on the selective breeding of individuals with superior phenotypes to allow them to perform better as well as survive and thrive in the prevailing environment. This approach has been extremely successful in increasing the quantity of agricultural output, however, recent advances in genetic technologies which not only enabled identification of genetic markers associated with the health and production traits but also led to the information of their entire genome. Marker assisted selection (MAS) which offers several merits over conventional phenotypic selection, has been integrated in the breeding program for genetic improvement of livestock. MAS strategy targets one or few alleles governing the particular traits thereby resulting in the selection of individuals with superior alleles. This strategy results in a small number of individuals having a large influence on the genepool which in turn results in the loss of genetic diversity. Recently, genomic selection which involves selection for numerous genetic markers dispersed across the genome contributing to multiple traits has been seen as an ideal approach to estimate the breeding value as well as maintaining the genetic diversity (2). Ruminants comprise major livestock species among the domesticated animals. Ruminants harbors complex microbial communities in their fore stomach known as rumen which are essential for conversion of coarse feed into digestible compounds such as volatile fatty acids and bacterial proteins, which in-turn determines the animal health and productivity (Pope et al., 2012). The rumen microbial community providing such beneficial functions is dominated by bacteria followed by anaerobic protozoa, fungi and bacteriophages (3). Recently, microbiome dynamics in response to change in the diet suggested significant impact of diet on rumen microbiome (4). These microbial dynamics suggested key role played by specific microbial communities in the degradation of fiber rich diet. Among the all rumen microbial species, less than 11% are cultivable (5). The availability of complete genome sequence of rumen microbial communities would further facilitates devising culture media for supporting the culture of these microbial species. In the near future, we hope that many of these species may hold potential to be used as probiotics to enhance digestibility and thereby production. The ability of rumen microflora to degrade the coarse feed is ascribed to their ligno-cellulolytic enzymes. These enzymes have evolved with their host depending on their feeding habitat. The ruminants are known for efficient conversion of lignocellulosic biomass to metabolic energy and hence expected to harbor enzymes with high potency so as to degrade the coarse plant fibers in few hours. These enzymes are useful for number of applications such as animal feed supplements to enhance the digestibility, for production of biofuel, fermentation industry, pulp and paper industry, textile industry, food and feed industry and production of other value-added commodities (6-8). The mining of cellulolytic enzyme from rumen microbiome has the potential to discover novel biocatalyst with high potency. Assisted reproductive technologies including embryo transfer, somatic cell nuclear transfer and transgenesis have been seen as promising approaches to introduce the novel and superior traits in the livestock such as high production traits, disease resistance, and production of biopharmaceuticals. However, these approaches require skilled manpower and expensive equipments. Further, limited success and ethical issues concerning genetically modified animals have restricted these technologies to the laboratory.