Weaning-associated feed deprivation stress causes microbiota disruptions in a novel mucin-containing in vitro model of the piglet colon(MPigut-IVM)

Background:Risk factors for the etiology of post-weaning diarrhea,a major problem in swine industry associated with enormous economic losses,remain to be fully elucidated.In concordance with the ethical concerns raised by animal experiments,we developed a new in vitro model of the weaning piglet colon(MPigut-IVM)including a mucin bead compartment to reproduce the mucus surface from the gut to which gut microbes can adhere.Results:Our results indicated that the MPigut-IVM is able to establish a representative piglet archaeal and bacterial colon microbiota in terms of taxonomic composition and function.The MPigut-IVM was consequently used to investigate the potential effects of feed deprivation,a common consequence of weaning in piglets,on the microbiota.The lack of nutrients in the MPigut-IVM led to an increased abundance of Prevotellaceae and Escherichia-Shigella and a decrease in Bacteroidiaceae and confirms previous in vivo findings.On top of a strong increase in redox potential,the feed deprivation stress induced modifications of microbial metabolite production such as a decrease in acetate and an increase in proportional valerate,isovalerate and isobutyrate production.Conclusions:The MPigut-IVM is able to simulate luminal and mucosal piglet microbiota and represent an innovative tool for comparative studies to investigate the impact of weaning stressors on piglet microbiota.Besides,weaning-associated feed deprivation in piglets provokes disruptions of MPigut-IVM microbiota composition and functionality and could be implicated in the onset of post-weaning dysbiosis in piglets.

Effects of paraprobiotics on bile acid metabolism and liver health in largemouth bass(Micropterus salmoides)fed a cottonseed protein concentrate-based diet

Cottonseed protein concentrate is a sustainable fishmeal alternative in aquafeed.A 10-week experiment was conducted to investigate the effects of a cottonseed protein concentrate-based diet with and without multi-strain yeast fractions(MsYF)on growth,bile acid metabolism,and health in largemouth bass.Four hundred fish(54.0±0.0 g)were casually distributed into 16 tanks(4 replicates/diet).Fish were fed with 4 iso-nitrogen and iso-energetic diets 3 times daily,including a fishmeal diet(FM),a soy protein concentrate-based diet(SPC;replacing 81%fishmeal protein),a cottonseed protein concentrate-based diet(CPC;replacing 81%fishmeal protein),and a CPC diet supplemented with 800 mg/kg MsYF(CPCY).Results showed that the survival of SPC was the lowest,i.e.,48%,with no apparent diet effect among other treatments;we omitted the SPC in additional analyses.Fish fed cottonseed protein concentrate-based diets showed lower growth than FM(P<0.05).Fish fed CPC showed the highest nuclear dense hepatic phenotypes ratio(50%),followed by CPCY(33%)and FM(17%).Further,dietary CPC increased hepatic total cholesterol and triglyceride levels with concurrently increased cholesterol syn-thesis but decreased triglyceride synthesis-associated transcription levels(P<0.05).Furthermore,di-etary CPC increased bile acid synthesis but decreased bile acid transport-associated transcription levels(P<0.05),and then induced an increment of plasma cholic acid and hepatic chenodeoxycholic acid content and the decrement of genus Romboustia(P<0.05).Regarding the effect of MsYF,fish fed CPCY reduced hepatic lipid accumulation and total plasma bile acid content(P<0.05)compared to CPC,suggesting an improvement in liver health.Also,dietary MsYF could reverse the microbiota community structure showing a similar gut microbial composition to FM.In conclusion,81%of fishmeal protein replaced by cottonseed protein concentrate suppressed growth and liver health,while dietary MsYF might mitigate the negative impact of a high cottonseed protein concentrate level diet on liver functions via gut microbiota regulation.