Mulberry leaf supplementation inhibits skatole deposition by regulating gut microbiota and upregulating liver cytochrome P4501A1 expression in finishing pigs

Skatole,a strong fecal odor substance,is generated through microbial degradation of tryptophan in the animal hindgut.It easily accumulates in adipose tissue and affects meat quality.In this study,the effect of mulberry leaf supplementation on skatole in finishing pigs was studied.In a 35-day trial,20 finishing pigs(barrows and gilts)were fed with a basal diet or basal diet with 6%mulberry leaves.Growth performance of the pigs(n=10)was automatically recorded by a performance-testing feeder system and 8 pigs in each treatment were slaughtered and sampled for the remaining tests.Skatole and short-chain fatty acids were detected using HPLC and gas chromatography,respectively.Fecal microbiota were analyzed using 16S r RNA gene sequencing.The metabolomics analysis of feces and serum was performed with UHPLC-MS/MS.The major cytochrome P450(CYP)enzymes that catalyze skatole degradation in the liver were tested by using RT-PCR and Western blot.Effects of major bioactive compounds in mulberry leaves on the CYP genes were verified in the hepatic cell line Hep G2 in an in vitro test(n=3).In finishing pigs,mulberry leaf supplementation had no significant effect on the average daily gain,average daily feed intake,and feed conversion ratio(P>0.05),but reduced skatole levels in feces,serum,and backfat(P<0.05),and increased acetic acid levels in feces(P=0.027).Mulberry leaf supplementation decreased the relative abundance of the skatole-producing bacteria Megasphaera and Olsenella(P<0.05).Indole-3acetic acid,the intermediate that is essential for skatole production,was significantly reduced in feces by mulberry leaf supplementation(P<0.05)and was positively correlated with skatole content in feces(P=0.004).In pigs treated with mulberry leaves,liver CYP1A1 expression was increased(P<0.05)and was negatively correlated with skatole content in backfat(P=0.045).The in vitro test demonstrated that mulberry leaf polyphenols and polysaccharides could directly stimulate CYP1A1 expression in hepatic cells.These findings suggest that mulberry leaf supplementation reduces skatole production and deposition in finishing pigs by regulating the gut microbiota and promoting skatole degradation in liver.

Cyclic-acyclic monomers metathesis polymerization to access photodegradable polydicyclopentadiene and polyethylene-like materials

The development of degradable and recyclable polymers is an attractive strategy to tackle the post-consumption pollution issue of commercial plastics.Cyclic-acyclic monomers metathesis polymerization(CAMMP)has been recently reported to produce degradable thermoset,thermoplastic and elastomeric polymers,and their degradability is enabled with addition of various chemicals.In this contribution,we demonstrate that the utilization of diene comonomers containing photodegradable moiety can give access to thermoset and thermoplastic materials bearing photo-degradation capabilities.The copolymerization of a series easily accessible diene comonomers bearing photodegradable ortho-nitrobenzyl moieties with dicyclopentadiene(DCPD)or cyclooctene(COE)leads to the formation of photodegradable p DCPD thermosets and p COE thermoplastic polymers with mechanical properties comparable to their non-degradable counterparts.Most importantly,their photo-degradation properties can be efficiently tuned with the addition of ultraviolet absorber during in-situ polymerization.