Black soldier fly and gut health in broiler chickens:insights into the relationship between cecal microbiota and intestinal mucin composition

Background:The relationship between diet and intestinal microbiota and mucin composition appears to be fundamental for poultry gut health.The effects of insect meal(whose role as alternative feed ingredient is now well recognized)on gut microbiota and mucin composition have recently been reported in Tenebrio molitor-fed free-range and broiler chickens,but no data are currently available for Hermetia illucens(HI)-fed broilers.The present study evaluated the effects of dietary HI meal inclusion on cecal microbiota and intestinal mucin composition of broiler chickens.Results:A total of 256 male broiler chickens were allotted to 4 dietary treatments(control diet[C]and 5%,10%and 15%HI meal inclusion,with 8 replicate pens/treatment and 8 birds/pen)and slaughtered at 35 d of age(2 animals/pen,16 birds/diet).The cecal microbiota assessment by 16S rRNA amplicon based sequencing showed lower alpha diversity in HI15 chickens(Shannon,P<0.05)and higher beta diversity(Adonis and ANOSIM,P<0.001)in birds fed HI diets than C.Furthermore,HI15 birds displayed significant increase of the relative abundance of Proteobacteria phylum(False Discovery Rate[FDR]<0.05)when compared to HI10.L-Ruminococcus(Ruminococcus from Lachnospiraceae family),Faecalibacterium,Blautia and Clostridium genera were found to be characteristic of HI5 cecal microbiota(FDR<0.05),while broiler chickens fed HI10 and HI15 diets were characterized(FDR<0.05)by Lactobacillus and Ruminococcus(HI10)and Bacteroides,Roseburia and Helicobacter genera(HI15).Periodic-acid Schiff,Alcian Blue pH 2.5 and high iron diamine staining on small and large intestine also demonstrated lower mucin staining intensity in the intestinal villi of HI10 and HI15 birds than C(P<0.05).Conclusions:Dietary HI meal utilization at low inclusion levels(i.e.,5%)positively influenced either the cecal microbiota or the gut mucin dynamics in terms of selection of potentially beneficial bacteria and increase in villi mucins.However,high inclusion levels(in particular the 15%)may have a negative influence in terms of partial reduction of microbial complexity,reduction of potentially beneficial bacteria,selection of bacteria with mucolytic activity and decrease in villi mucins.

Effects of dietary Hermetia illucens meal inclusion on cecal microbiota and small intestinal mucin dynamics and infiltration with immune cells of weaned piglets

Background: The constant interaction between diet and intestinal barrier has a crucial role in determining gut health in pigs. Hermetia illucens(HI) meal(that represents a promising, alternative feed ingredient for production animals) has recently been demonstrated to influence colonic microbiota, bacterial metabolite profile and mucosal immune status of pigs, but no data about modulation of gut mucin dynamics are currently available. The present study evaluated the effects of dietary HI meal inclusion on the small intestinal mucin composition of piglets, as well as providing insights into the cecal microbiota and the mucosal infiltration with immune cells.Results: A total of 48 weaned piglets were randomly allotted to 3 dietary treatments(control diet [C] and 5% or10% HI meal inclusion [HI5 and HI10], with 4 replicate boxes/treatment and 4 animals/box) and slaughtered after61 days of trial(3 animals/box, 12 piglets/diet). The cecal microbiota assessment by 16 S r RNA amplicon based sequencing showed higher beta diversity in the piglets fed the HI-based diets than the C(P < 0.001). Furthermore,the HI-fed animals showed increased abundance of Blautia, Chlamydia, Coprococcus, Eubacterium, Prevotella,Roseburia, unclassified members of Ruminococcaceae, Ruminococcus and Staphylococcus when compared to the C group(FDR < 0.05). The gut of the piglets fed the HI-based diets showed greater neutral mucin percentage than the C(P < 0.05), with the intestinal neutral mucins of the HI-fed animals being also higher than the sialomucins and the sulfomucins found in the gut of the C group(P < 0.05). Furthermore, the piglets fed the HI-based diets displayed lower histological scores in the jejunum than the other gut segments(ileum [HI5] or ileum and duodenum [HI10], P < 0.05).Conclusions: Dietary HI meal utilization positively influenced the cecal microbiota and the small intestinal mucin dynamics of the piglets in terms of selection of potentially beneficial bacteria and preservation of mature mucin secretory architecture, without determining the development of gut inflammation. These findings further confirm the suitability of including insect meal in swine diets.

Dried fruit pomace inclusion in poultry diet:growth performance, intestinal morphology and physiology

Background: Fruit pomaces are by-products rich in polyphenol compounds and dietary fiber. They seem to play an important role in regulating the gut microbiota, morphology and physiology. The aim of this study was to assess whether apple(A), blackurrant(B) or strawberry(S) pomaces could be suitable ingredients in broiler diets and their effect on gut health. A total of 480 male broilers were randomly allotted to 8 dietary treatments with lower(3%-L) or higher(6%-H) dietary fiber content: two control groups(CL/CH), two A diets(AL/AH), two B diets(BL/BH), two S diets(SL/SH). Diet and fruit pomaces were chemically analyzed to assess polyphenol concentration and fibre fraction content. After the evaluation of growth performance, 6 birds/group were slaughtered at 35 days of age. Morphometric and histopathological investigations were performed on duodenum, jejunum and ileum.Excreta were collected to perform microbiota evaluation by 16 S DNA sequencing. Weight, viscosity, enzymatic activity, short chain fatty acid(SCFAs) and ammonia concentration were determined in ileum and/or ceca content.Results: A pomace and A diets showed the lowest polyphenol content and the highest content of soluble fibre fraction. No significant differences were observed for growth performance, gut morphometry and histopathology(P > 0.05). Dietary fruit pomace inclusion increased the weight of ileum and ceca and the ileum digesta viscosity(P < 0.05). In the ileum, A and S groups showed lower bacterial α-glucosidase activity than C groups. Moreover,small intestine SCFAs concentration was higher in fruit pomaces diets(P < 0.05). In ceca, B and S groups showed lower ammonia concentration and higher SCFAs than C. Dietary treatments also influenced the activity of α-glucosidase, α-galactosidase, β-galactosidase β-glucuronidase and xylase. Regarding microbiota, at phylum level,Firmicutes were differentially abundant across treatment(maximum for C and minimum in S, FDR > 0.05). At genus level, an increase of Weissella in AH and Erwinia in S/B diets, as well as a decrease of Lactobacillus in all fruit pomace groups were recorded(P < 0.05).Conclusions: Fruit pomaces could be suitable ingredients in poultry nutrition even if further studies are needed to better understand which doses is more recommended to avoid negative effects on gut microbiota.

Soil bacterial communities under slash and burn in Mozambique as revealed by a metataxonomic approach

The slash-and-burn system is a subsistence agronomical practice widespread in tropical areas worldwide.This system has been extensively studied,especially for its impacts on agronomical aspects and soil physicochemical properties;however,knowledge of soil microbial diversity under slash and bum is scarce.In this study,for the first time,soil bacterial diversity of three locations from Central Mozambique,where slash and burn has been practiced for different durations of the forest fallow period(ca.25,35,and 50 years),was elucidated through a metataxonomic approach.Bacterial communities were evaluated in the genetic horizons of soils under charcoal kilns,crop fields,and forests.The aim of this study was to examine the influence of spatial(location and land use),temporal(forest fallow period),and vertical(horizon)variations on bacterial community structure in relation to soil physicochemical properties.Metataxonomic analysis detected 25 different phyla whose distribution varied horizontally and vertically in relation to soil properties(i.e.,p H,easily oxidizable organic carbon,total nitrogen,and available phosphorus),as well as particle size distribution and mineralogical composition.Such properties were strongly affected and altered by land-use management;in particular,charcoal kilns exhibited better soil properties and greater differences in bacterial community than crop fields and forests,which were quite similar.This might suggest the inability of a forest fallow period shorter than 50 years to improve soil fertility and induce changes in bacterial community.The uncommon application of the pedological approach for microbial evaluation facilitated the detection of a clear separation in bacterial composition along the soil profile,with eutrophic bacteria mainly located in the A horizon whereas oligotrophic bacteria were found in the Bo horizon.These horizontal and vertical heterogeneities in the same study represent a novelty for bacterial metataxonomic analysis.