Improvement Of Production Traits Research Articles

Evaluation of Internal Reference Genes for Quantitative Expression Analysis by Real-Time PCR in Ovine Whole Blood

The use of reference genes is commonly accepted as the most reliable approach to normalize qRT-PCR and to reduce possible errors in the quantification of gene expression. The most suitable reference genes in sheep have been identified for a restricted range of tissues, but no specific data on whole blood are available. The aim of this study was to identify a set of reference genes for normalizing qRT-PCR from ovine whole blood. We designed 11 PCR assays for commonly employed reference genes belonging to various functional classes and then determined their expression stability in whole blood samples from control and disease-stressed sheep. SDHA and YWHAZ were considered the most suitable internal controls as they were stably expressed regardless of disease status according to both geNorm and NormFinder software; furthermore, geNorm indicated SDHA/HPRT, YWHAZ/GAPDH and SDHA/YWHAZ as the best reference gene combinations in control, disease-stressed and combined sheep groups, respectively. Our study provides a validated panel of optimal control genes which may be useful for the identification of genes differentially expressed by qRT-PCR in a readily accessible tissue, with potential for discovering new physiological and disease markers and as a tool to improve production traits (e.g., by identifying expression Quantitative Trait Loci). An additional outcome of the study is a set of intron-spanning primer sequences suitable for gene expression experiments employing SYBR Green chemistry on other ovine tissues and cells.

Improvement in production traits by mass spawning type crossbreeding in bay scallops

Bay scallop culture has become a major sector in marine culture industry in China since its first introduction in early 1980s. However, despite various efforts including several re-introductions, decreases in major production traits such as survival and growth rates are still a major concern to the industry. This study aimed to evaluate the performance of offspring derived from mass spawning type crossbreeding between different populations in bay scallops. The results showed that significant differences in growth and survival existed among the four intra-population crosses at larval stages, but not at the adult stage. Increases in growth and survival rates were observed in most inter-population crosses at larval stages and in all inter-population crosses at the adult stage. The survival rate of the best inter-population crosses was 156.7% higher than the average survival rate of all the intra-population crosses. Through mass spawning type crossbreeding between different populations, we were able to produce offspring with improved production traits and the results may have immediate application in bay scallop culture.

Revealing the history of sheep domestication using retrovirus integrations.

The domestication of livestock represented a crucial step in human history. By using endogenous retroviruses as genetic markers, we found that sheep differentiated on the basis of their "retrotype" and morphological traits dispersed across Eurasia and Africa via separate migratory episodes. Relicts of the first migrations include the Mouflon, as well as breeds previously recognized as "primitive" on the basis of their morphology, such as the Orkney, Soay, and the Nordic short-tailed sheep now confined to the periphery of northwest Europe. A later migratory episode, involving sheep with improved production traits, shaped the great majority of present-day breeds. The ability to differentiate genetically primitive sheep from more modern breeds provides valuable insights into the history of sheep domestication.

Consequences of selection for improving production traits on the frequency of deleterious alleles for fitness1

In this study the effect of artificial selection on BLUP EBV for production traits on the allele frequencies of a pleiotropic QTL affecting both production and disease susceptibility was investigated. Stochastic simulations were used to model artificial selection on a production trait that is controlled, in part, by a biallelic QTL that also controls susceptibility to disease. The QTL allele increasing production also increased susceptibility to disease. Different modes of action and proportions of variation accounted for by the QTL were assessed for the production trait. The main results indicated that alleles that confer susceptibility to the disease could be maintained in the population over a long period, depending on the mode of action of the QTL. In addition, the results of the study indicate that, under various conditions, it is possible to find pleiotropic QTL that control 2 traits despite these traits appearing to be uncorrelated. Therefore, in practice, an estimate of the genetic correlation between 2 traits may be misleading when the presence of such a QTL exists. The results of this study have implications for breeding programs. For example, if a pleiotropic QTL exists that favors heterozygotes for a production trait, it would be very difficult to remove disease susceptibility alleles via traditional selection methods.

Identifying the Future Needs for Long-Term USDA Efforts in Agricultural Animal Genomics

Agricultural animal research has been immensely successful over the past century in developing technology and methodologies that have dramatically enhanced production efficiency of the beef, dairy, swine, poultry, sheep, and aquaculture industries. In the past two decades, molecular biology has changed the face of agricultural animal research, primarily in the arena of genomics and the relatively new offshoot areas of functional genomics, proteomics, transcriptomics, metabolomics and metagenomics. Publication of genetic and physical genome maps in the past 15 years has given rise to the possibility of being able finally to understand the molecular nature of the genetic component of phenotypic variation. While quantitative geneticists have been remarkably successful in improving production traits, genomic technology holds potential for being able to lead to more accurate and rapid animal improvement, especially for phenotypic traits that are difficult to measure.Recently, the agricultural research community has been able to capitalize on the infrastructure built by the human genome project by sequencing two of the major livestock genomes (Gallus domesticus and Bos Taurus). The 2005 calendar year is truly unprecedented in the history of agricultural animal research since draft genome sequences were completed for chickens and cattle. In addition, sequencing the swine and equine genome was initiated in early 2006. We now have in place a powerful toolbox for understanding the genetic variation underlying economically important and complex phenotypes. Over the past few years, new challenges have emerged for animal agriculture. Enhancements in production efficiency have not come without some negative side effects on animal well-being and longevity in production environments, including losses in reproductive efficiency, increased stress susceptibility, increased animal waste issues, and increased susceptibility to animal metabolic and infectious diseases. When considered in concert with societal concerns in the areas of natural resource conservation and protection, animal welfare, and food safety, it is clear that publicly supported agricultural research must be focused on enhancing the functionality and well-being of livestock and poultry in environmentally neutral production systems in the future. Realizing the great potential for animal genomics to address these and other issues, a workshop was convened by the U. S. Department of Agriculture (USDA) in Washington, DC in September of 2004. The workshop was entitled "Charting the Road Map for Long Term USDA Efforts in Agricultural Animal Genomics". This paper summarizes the proceedings of the workshop and the resulting recommendations. The need for a cohesive, comprehensive long-term plan for all of USDA's research efforts in animal genomics was evident at the workshop, requiring further integration of the efforts of the USDA's Cooperative State Research, Education, and Extension Service (CSREES) and the USDA's Agricultural Research Service (ARS) to achieve the greatest return on investment.

Investigation of major fattening traits of male crosses F1 generation of German fleckvieh breed and domestic Simmental breed

Major fattening and growth traits of performance tested bulls from two groups are presented in this paper. Bulls obtained in pure breed Fleckvieh x Fleckvieh were investigated/evaluated in test stations in Germany, and male crosses with Domestic Simmental cows in domestic centers for AI (Krnjaca and Velika Plana). In observing two groups of young bulls statistically significant differences were registered (p< 0,01**) for following traits chest depth, chest girth, and daily gain, whereas for body mass at the end of test and height of withers differences were at level p> 0,05 ns. Group of young bulls F x F tested in Germany achieved in average greater chest depth and chest girth and realized higher daily gains during test period. Group of crosses tested in our conditions in domestic test stations realized higher values for length of carcass and almost identical body mass at the end of test period. In other words, improvement of production traits and correction of exterior characteristics of domestic population of cattle through import of breeding animals and their semen is justified only when positively tested breeding material is imported which is adequate for our purpose and breeding objective.

Cellulase fermentation on a novel substrate (waste cardboard) and subsequent utilization of home-produced cellulase and commercial amylase in a rabbit feeding trial

Cellulase and amylase enzymes are increasingly being used as feed additives in animal nutrition. Those are mainly applied in order to improve the nutritional value of feed by partially degrading its fiber content, which has major importance during the early post-weaning period of young animals possessing inadequate digestive enzyme activities. Due to their commercial availability at low cost, the utilization of amylases as animal feed additive can be highly recommended, while the high price of cellulases actually makes their use as a feed additive unreasonable. A promising way to gain cheap cellulases is to conduct the enzyme fermentation process on novel substrates, which are readily available at no cost. In this study, the utilization of old corrugated cardboard (OCC) as a novel fermentation substrate has been investigated for cellulase enzyme fermentation by Trichoderma reesei Rut C-30. Batch fermentation experiments were carried out in shake-flasks and in a 30 l laboratory fermenter. The OCC feedstock proved to be a suitable fermentation substrate, a filter paper activity (FPA) of as high as 2.27 FPU ml −1 was achieved in the fermenter, which corresponds to a yield of 227 FPU g −1 cellulose. The maximum productivity achieved was 35.7 FPU l −1 h −1. The subsequent utilization of this cellulase enzyme preparation was investigated as additive of commercial rabbit compound feed in order to improve its digestibility during the early post-weaning period. In parallel, commercial amylase preparations were also tested for the same purposes. The results of animal feeding experiments showed, that enzyme supplementation of the complete feed improved production traits, as it increased the digestibility of nutrients and thus reduced the mortality caused by digestive disorders.

Foreign DNA: integration and expression in transgenic plants.

Gene transfer to plants is now a routine procedure, and the number of species amenable to transformation is increasing rapidly. The introduction of foreign DNA into plants allows the creation of engineered plant lines with improved production traits, resistance to pests, pathogens or herbicides, or the ability to synthesize speciality recombinant proteins such as human hormones, enzymes and antibodies. Many of these plants are now reaching commercial status (1). Although the applications of plant genetic engineering are diverse, there are only two basic strategies for stable plant transformation. The first depends on the natural ability of soil bacteria, such as Agrobacterium tumefaciens, to transfer a small segment of DNA from a resident plasmid into the plant cell (2). The second is ‘direct DNA transfer’ and encompasses a range of techniques where DNA is either physically forced into the plant cell, or the cell is persuaded to take up DNA from the surrounding medium. Examples of these techniques include particle bombardment (3), electroporation (4), the transformation of protoplasts mediated by polyethylene glycol (PEG) (5), and transformation using silicon carbide whiskers (6).KeywordsTransgenic PlantParticle BombardmentTrans GeneIllegitimate RecombinationTransgenic LocusThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Taiwan's GM foods labelling legislation — a review

Genetically engineered food products have several advantages over their conventional counterparts; i.e. improvement of production traits is rapid, and genetic information can be transferred across species. However, introduction of a new gene into food crops may lead to emergence of altered composition and nutritional value, allergenicity and toxicity. To meet the requirements to environmental and food safety, sale of GM foods in Taiwan must comply with regulations, guidelines and labelling of various governmental agencies. Among these agencies, the Department of Health is responsible for the safety and labelling of GM foods, and has promulgated regulations stipulating the labelling of food products containing GM ingredients. Our initial step on the mandatory labelling of GM foods would let consumers to decide to purchase GM products.

Reciprocal crosses between Alabio and Mojosari ducks : early egg production

alternative to increasing productivity and production efficiency. Crossbreeding has been used widely for increasing productivity, and in this experiment Alabio and Mojosari ducks were crossed reciprocally in order to evaluate their egg production and egg quality, when compared to their parental breeds. Four genotypes AA, AM, MA and MM were compared and each consisted of 50 layer ducks. Each animal was kept in individual cage, and individual egg production and egg quality were recorded. They were given layer feed containing 20% crude protein and 3000 kcal/kg metabolisable energy. Results showed that the crossbred ducks (AM and MA) laid eggs earlier than their parental breeds (AA and MM), and MA laid earlier than AM. The weight of first eggs of the crossbreeds did not differ significantly, AM was the same as MM and MA the same as AA. For the body weight at first lay, MA and AM weighed in between their parental breeds, AA was the heaviest and then followed by MA, AM and MM. For the 3-month egg production, MA ducks laid significantly more egg than the other 3 genotypes, and this is related to the age of first lay being the earliest. In terms of egg quality such as egg weight, yolk color, weight and thickness of shell, weight of the white and HU value, the crossbred ducks showed quality in between AA and MM. The AM ducks tended to be closer to MM and MA closer to AA, and this shows a strong influence of maternal effects. The average level of heterosis for weight of first egg is 2.41% and for 3-month egg production is 2.1%, but for MA cross the heterosis level is 11.69% for egg production. The overall results showed that crossbreeds between Alabio and Mojosari have the potential in improving production traits in the effort to increase productivity and production efficiency. Key words : Duck, crossbred, production egg

Applications of the random amplified polymorphic DNA (RAPD) assay for genetic analysis of livestock species

Abstract Molecular genetic technologies are revolutionizing genetic analyses of livestock species. DNA‐based polymorphisms are being used for marker assisted selection strategies, parentage testing, species identification, and population genetic studies. These polymorphisms also provide the foundation for genetic linkage maps, which are being used to identify loci for economically‐important variation and expedite the rate of improvement in production traits. Traditionally, DNA‐based markers such as restriction fragment length polymorphisms (RFLPs) and microsatellites have been used for genetic analyses. A relatively new method for detecting polymorphic markers is the random amplified polymorphic DNA (RAPD) assay. This assay, which is based on the polymerase chain reaction (PCR), uses short oligonucleotide primers of arbitrary sequence to amplify discrete regions of the genome. On the basis of numerous successful applications in other species (e.g. plants, microorganisms, and insects) and recently reported...

Divergent selection for incidence of degenerative myopathy of the Musculus supracoracoideus of meat-type chickens.

The response to three generations of selection for incidence of degenerative myopathy of the Musculus supracoracoideus (DMS) in meat-type chickens was studied. From each of two genetic bases named E and F, which were derived from two commercial broiler stocks, a high incidence, low incidence, and a nonselected control strain were initiated. Selection of breeders to produce Generations 1 and 2 was based on the incidence of DMS in their parents after induced wing exercise; mass selection for plasma creatine kinase levels after induced wing exercise was used to produce Generation 3. Little genetic progress in selection occurred in Generations 1 and 2. There was a response in Generation 3, especially in Base E selected for low incidence. Heritability of incidence of DMS was estimated to be .48. Body weights at 8 weeks of age, 18 weeks of age, and breast angle at 18 weeks of age of Generation 3 were greater (P less than .05) for affected than nonaffected birds and positively correlated phenotypically with incidence of DMS. Genetic correlations were extremely variable. The higher incidence of DMS in birds with desirable traits suggests that the breeder must use a multitrait selection program to reduce incidence of DMS as well as improve production traits.