Impact of C/N/P dietary nutrient on manure characteristics: Pollutant fractions and microbial community

Abstract

Regulation of labile fraction of excreted manure represents a promising advance for environmental pollution mitigation. However, investigation of the properties of various pollutant fractions within manure and potential influence of dietary nutrient fractions on the release of labile manure remains unclear. Feeding trials involving pigs at three distinct growth stages fed by diets with nine different energy levels were conducted and the characteristics of labile manure generated under various treatments based on nutrient profiles were analyzed. The impact of dietary nutrient fractions on variables such as labile manure pollutants, pig performance, manure weight and dominant microorganisms were evaluated via theoretical modeling and correlation analysis. The results indicated that critical dietary nutrient factors such as dietary C fraction, protein N-materials and dietary P fraction varied respectively with pig growth stages. The labile manure composition and proportion were influenced by dietary C/N/P fractions and indigestible components, through regulation of the structure of the gut microbiota and the relative abundance of gut microbes. This study finds that initiating dietary regulatory measures could effectively control the release of labile manure and reduce its proportion in the overall manure and thus, provides a novel approach to achieve manure source pollution control, ensure environmental-friendly diet formula and mitigate manure-related environmental pollution.