Date Full Report Received05/04/2019
Date Abstract Report Received05/04/2019
InvestigationInstitution: North Carolina State University
Primary Investigator: Dr. Christian Maltecca PhD.
Co-Investigators: Francesco Tiezzi
Funded ByNational Pork Board
The efficiency of producing saleable meat products is primarily determined by costs associated with feed and by the amount of and quality of lean meat produced. Utilizing feed resources more efficiently has become a definite challenge that faces the livestock industry. Recent efforts have been devoted to identifying and exploit the genomic variability of individual pigs in increasing feed efficiency. Despite its success, this approach presents logistical as well as technical limitations related to obtaining accurate individual feed intake records as well as defining and using different feed efficiency measures. Perhaps most importantly, a continued effort concentrating only on the pig variability for efficiency would inevitably lead to diminished marginal gains, incurring in concomitant losses of overall fitness and genetic diversity over time. The amount and type of bacteria present in the gut of individuals represent a key part of all mammalian organisms. The makeup of the microbiome represents a vast pool of genomic diversity that contributes to the individual physiology and health. Particularly, the intestinal microbiome directly affects the degradation of carbohydrates, provides short-chain fatty acids, mitigates and alter the effect
of potentially toxic compounds and produce essential vitamins. The impact of environmental factors, such as nutrition, stressors and challenges associated with weaning in pigs and management, have been characterized in pigs. Nonetheless, the composition and function of a healthy microbial ecosystem have not been qualitatively and quantitatively defined and used as a tool to maximize animal health and performance. Particularly, microbiome composition has yet to be studied at large scales, including large sampling conducted through several stages of the production life. The overall objective of this study was to assess the power of microbiome predictions based on fecal samples, to foresee growth and carcass composition in populations of healthy pigs. Specific objectives of the proposal were: 1- Quantify the impact of microbiome composition on lean growth in swine. 2- Quantify the heritability of relative taxa abundance in swine. 3- Explore the hypothesis that specific regions of the genome are related to the ability of the host to select relative taxa abundance. 4- Evaluate the effectiveness of the inclusion of microbiome taxa relative abundance as direct source of variation in predicting growth and carcass traits in pigs.
To investigate these objectives 3000 pigs progeny of 28 founding Duroc sires were genotyped with a commercial SNP panel and their fecal microbiome was collected at three time-points during their growth trial. Phenotypic observations were collected on several growth and carcass composition traits at the same time. The results of the current research show that:
• Gut microbiome composition directly affects growth and carcass traits in pigs. Different microbial populations separate individuals on the basis of growth and fatness with specific microbial species significantly related to fat and lean deposition.
• Early microbiome measures are less reliable predictors of growth and microbial information on pigs might be best collected at later life stages.
• Microbial composition is at least partially under direct genetic control so that it could be potentially manipulated with the use of selection tools. Heritabilities of microbial diversity as well as individual taxa range from low to moderate and are replicable across scenarios.
• Fecal microbiota diversity could potentially be used as an indicator trait to improve traits that are expensive to measure.
• The inclusion of microbial predictors could potentially be used to promote fast growth of individuals while limiting fat accumulation.