https://www.selleckchem.com/PARP.html Prebiotics may modify the biological processes in the chickens' gastrointestinal tract to improve poultry performance and health. Prebiotics are natural feed additives that offer many economic advantages by decreasing mortality rates, increasing growth rates, and improving birds' feed efficiency. Prebiotic action potentially affects the degradation of indigestible dietary compounds, the synthesis of nitrogen components and vitamins, and simplifies the removal of undesirable elements in the diet. Prebiotics could also induce desirable gut microbiome modifications and affect host metabolism and immune health. It is worth mentioning that gut bacteria metabolize the prebiotic compounds into organic compounds that the host can subsequently use. It is important to limit the concept of prebiotics to compounds that influence the metabolism of resident microorganisms. Any medicinal component or feed ingredient beneficial to the intestinal microecosystem can be considered a prebiotic. In this review, the impacts of prebiotics on the gut microbiome and physiological structure are discussed, emphasizing the poultry's growth performance. The current review will highlight the knowledge gaps in this area and future research directions.Heavy fuel oil (HFO) accounts for approximately 80% of the fuel consumption of ocean-going ships in the world. Multiple toxic species are found in HFO exhaust, however, carbonaceous substances emitted from low-speed marine engine exhaust at different operating loads have not been thoroughly addressed. Therefore, a bench test for a low-speed marine engine with HFO fuel under different operating modes was carried out in this study. Emission factors and characteristics of CO2, CO, organic carbon (OC), elemental carbon (EC), as well as OC and EC fragments, organic matters of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) are given and discussed. Combined with the correlation analysis results among the measured