Modulation of intestinal microbiota, morphology and mucin composition by dietary insect meal inclusion in free-range chickens

Choice of 16S ribosomal RNA primers affects the microbiome analysis in chicken ceca

We evaluated the effect of applying different sets of 16S rRNA primers on bacterial composition, diversity, and predicted function in chicken ceca. Cecal contents from Ross 708 birds at 1, 3, and 5 weeks of age were collected for DNA isolation. Eight different primer pairs targeting different variable regions of the 16S rRNA gene were employed. DNA sequences were analyzed using open-source platform QIIME2 and the Greengenes database. PICRUSt2 was used to determine the predicted function of bacterial communities. Changes in bacterial relative abundance due to 16S primers were determined by GLMs. The average PCR amplicon size ranged from 315 bp (V3) to 769 bp (V4–V6). Alpha- and beta-diversity, taxonomic composition, and predicted functions were significantly affected by the primer choice. Beta diversity analysis based on Unweighted UniFrac distance matrix showed separation of microbiota with four different clusters of bacterial communities. Based on the alpha- and beta-diversity and taxonomic composition, variable regions V1–V3(1) and (2), and V3–V4 and V3–V5 were in most consensus. Our data strongly suggest that selection of particular sets of the 16S rRNA primers can impact microbiota analysis and interpretation of results in chicken as was shown previously for humans and other animal species.

Effect of Graded Substitution of Soybean Meal by Hermetia illucens Larvae Meal on Animal Performance, Apparent Ileal Digestibility, Gut Histology and Microbial Metabolites of Broilers

Simple Summary

Soybean meal (SBM) constitutes the major protein source in European poultry production, meaning a high dependency on imports and a reduced sustainability of produced meat. To cope with this challenge, alternative protein sources are needed, and insects are considered as a novel, alternative protein source in broiler nutrition. The objective of the present study was to evaluate the replacement of 15 or 30% of crude protein (CP) from SBM with Hermetia illucens (HI) defatted larvae meal CP regarding broiler performance, carcass traits, apparent ileal CP and amino acid (AA) digestibility, intestinal morphology, and microbial metabolites. The data showed impaired performance and lower ileal CP and AA digestibility with 30% substitution of CP from SBM with HI larvae meal CP. However, lower substitution, i.e., 15% substitution of SBM CP with HI larvae meal, for broiler feeds seems possible without impairment in animal performance and digestion variables and should be pursued in the future.

Abstract

The usage of insects as an alternative protein source for broiler feeds may help to reduce the dependency on soybean meal (SBM) imports. Therefore, the present study aimed to evaluate the replacement of 15 (SL15) or 30% (SL30) of crude protein (CP) from SBM with Hermetia illucens (HI) defatted larvae meal regarding broiler performance, carcass traits, apparent ileal digestibility, intestinal morphology, and microbial metabolites. Concerning the performance, body weight was similar for the control (CON) and SL15, but lower for SL30 during all feeding phases. In addition, average daily feed intake was higher in SL15 and SL30 compared to CON in the starter phase, but this effect vanished during grower and finisher phase. The apparent ileal digestibility decreased for CP and some amino acids with increasing HI larvae meal in the diet. No or marginal alterations were observed for the intestinal morphometry as well as cecal microbial metabolites. In conclusion, partial replacement of 15% SBM CP with HI larvae meal in broiler diets without impairing animal performance or health seems possible. The growth suppression with 30% CP substitution may be caused by reduced apparent ileal digestibility but could not be clearly associated with adverse effects of hindgut fermentation or altered gut morphology.

Effect of Vitamin A Supplementation on Growth Performance, Serum Biochemical Parameters, Intestinal Immunity Response and Gut Microbiota in American Mink (Neovison vison)

Simple Summary

Vitamin A is critical throughout life, but utilization of vitamin A often results in local and systemic toxicity. This study investigated the effect of vitamin A supplementation on mink growth and health. The results show that vitamin A deficiency decreased the ADG, villus height, villus height/crypt depth ratio and mRNA expression levels of IL-22, Occludin and ZO-1. Vitamin A supplementation increased the diversity of jejunum bacteria, decreased the ratio of Firmicutes to Bacteroidetes and increased the relative abundance of Akkermansia and Lachnospiraceae NK4A136 group.

Abstract

This experiment investigated the effect of vitamin A supplementation on growth, serum biochemical parameters, jejunum morphology and the microbial community in male growing-furring mink. Thirty healthy male mink were randomly assigned to three treatment groups, with 10 mink per group. Each mink was housed in an individual cage. The mink in the three groups were fed diets supplemented with vitamin A acetate at dosages of 0 (CON), 20,000 (LVitA) and 1,280,000 IU/kg (HVitA) of basal diet. A 7-day pretest period preceded a formal test period of 45 days. The results show that 20,000 IU/kg vitamin A increased the ADG, serum T-AOC and GSH-Px activities, villus height and villus height/crypt depth ratio (p < 0.05). The mRNA expression levels of IL-22, Occludin and ZO-1 in the jejunum of mink were significantly higher in the LVitA group than those in the CON and HVitA groups (p < 0.05). Vitamin A supplementation increased the diversity of jejunum bacteria, decreased the ratio of Firmicutes to Bacteroidetes and increased the relative abundance of Akkermansia, uncultured bacterium f Muribaculaceae, Allobaculum, Lachnospiraceae NK4A136 group, Rummeliibacillus and Parasutterella. The comparison of potential functions also showed enrichment of glycan biosynthesis and metabolism, transport and catabolism pathways in the vitamin A supplementation groups compared with the CON group. In conclusion, these results indicate that dietary vitamin A supplementation could mediate host growth by improving intestinal development, immunity and the relative abundance of the intestinal microbiota.

A Comparison Study of the Caecum Microbial Profiles, Productivity and Production Quality of Broiler Chickens Fed Supplements Based on Medium Chain Fatty and Organic Acids

Simple Summary

The ban of growth promoters in poultry farming in the European Union has resulted in the development of alternatives. Among these alternatives, medium chain fatty acids (MCFAs) or organic acids (OAs) are considered to be suitable for in-feed use. However, their effect on microbiota modulation and the meat quality of broiler chickens are still under-investigated. The aim of this study was to estimate the influence of MCFAs and OAs supplements on the caecum microbial profiles, productivity and production quality characteristics of broiler chickens. The 42-days experiment was conducted using 900-day-old broiler chickens, allocated into three groups, consisting of 300 birds per group. The results indicated that the addition of OAs results in a more appropriate environment in the caecum for beneficial microorganisms rather than diets supplemented with MCFAs. These positive changes led to a higher efficiency of poultry productivity (higher body weight and lower mortality); however, for most of the analysed broilers’, technological parameters were not considerably influenced by treatments.

Abstract

The aim of this study was to evaluate the influence of medium chain fatty acids (MCFAs) and organic acids (OAs) supplements on the caecum microbial profiles, productivity and production quality characteristics of broiler chickens (BCs). BC (900 chicks) were attributed to three groups: (i) control; (ii) MCFAs group (BCs fed with feed supplemented with MCFAs); (iii) OAs group (BCs fed with feed supplemented with OAs). Broilers were slaughtered at the end of the trial (42 days old), and the caecum microbial profiles, productivity and production quality characteristics were analysed. Supplementation with OAs resulted in a more appropriate environment in the caecum for beneficial microorganisms than with a diet supplemented with MCFAs. This was supported by data on the presence of higher amounts and an increased species variety of probiotic bacteria (Lactobacillus and Bifidobacterium) in the caecum of birds. The above-mentioned changes of the caecum microbiota led to significantly higher villus height (p = 0.003) of the OAs broiler group and significantly lower crypt depth (p = 0.037). Notwithstanding the significant increase of acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids that were established in caecum samples from the MCFAs group, better parameters of broiler production performance (higher body weight and lower mortality) and carcass traits (higher both thigh and shin muscles with skin and bone weight; both shin muscles without skin and bone weight; abdominal fat yield) were found in the OAs-treated group. For chemical, physical and technological characteristics of breast meat samples, increased yellowness and water holding capacity by 14.7% and 2.3%, respectively, were found in MCFAs group samples. A more appropriate environment in the caecum for beneficial microorganisms could be obtained when BCs were fed with OAs supplement, comparing to MCFAs, and these positive changes were associated with higher efficiency of poultry production.

Modulation of Morphology and Glycan Composition of Mucins in Farmed Guinea Fowl (Numida meleagris) Intestine by the Multi-Strain Probiotic Slab51®

Probiotics have become highly recognized as supplements for poultry.Since gut health can be considered synonymous withanimal health, the effects of probiotic Slab51® on the morphology and the glycan composition of guineafowlintestine were examined. The probiotics were added in drinking water (2 × 1011 UFC/L) throughout the grow-out cycle.Birds were individually weighed andslaughtered after four months. Samples from the duodenum, ileum and caecum were collected and processed for morphological, morphometric, conventional and lectin glycohistochemical studies.The results were analyzed for statistical significance by Student's t test. Compared with control samples, probiotic group revealed (1) significant increase in villus height (p < 0.001 in duodenum and ileum; p < 0.05 in caecum), crypt depth (p < 0.001 in duodenum and caecum; p < 0.05 in ileum) and goblet cells (GCs) per villus (p < 0.001) in all investigated tracts; (2) increase in galactoseβl,3N-acetylgalacyosamine(Galβl,3GalNAc)terminating O-glycans and αl,2-fucosylated glycans secretory GCs in the duodenum; (3) increase in α2,6-sialoglycans and high-mannose N-linked glycans secretory GCs but reduction in GCs-secreting sulfoglycans in the ileum; (4) increase in Galβl,3GalNAc and high-mannose N-linked glycans secretory GCs and decrease in GCs-producing sulfomucins in the caecum; (5) increase in the numbers of crypt cells containing sulfate and non-sulfated acidic glycans. Overall, dietary Slab51® induces morphological and region-specific changes in glycoprotein composition of guinea fowl intestine, promoting gut health.

The Effect of Administration of a Phytobiotic Containing Cinnamon Oil and Citric Acid on the Metabolism, Immunity, and Growth Performance of Broiler Chickens

Simple Summary

In poultry farming, additives are sought after to ensure the living needs of birds, improve the health of birds, and improve growth performance. Noticeably, more and more hopes for obtaining such effects are being placed in plant additives, called phytobiotics, which are safe as natural additives, both for the health of birds and for not leaving toxic residues in final products (meat and eggs). A valuable phytobiotic ingredient is cinnamon, used in the form of an oil or a powder, which is obtained from the bark or leaves of the cinnamon tree. Cinnamon oil can stimulate the appetite, increase the secretion of digestive enzymes, stimulate immunity, have anti-allergic and detoxifying properties, and also have a positive effect on reducing sugar levels in the body. It has antimicrobial properties that destroy the cell membranes of pathogens, and, thanks to its antioxidant properties, it accelerates wound healing and stimulates the functioning and regeneration of intestinal epithelial cells. It is also antiparasitic, especially against gastrointestinal parasites. Due to the number of valuable properties of cinnamon oil, it seems advisable to find the most favorable dosage and time of application of this component to the chickens’ water, that may cause intended effects such as improving the health of chickens and increasing the efficiency of their rearing.

Abstract

It was postulated that a phytobiotic preparation containing cinnamon oil and citric acid added to drinking water for chickens in a suitable amount and for a suitable time would beneficially modify the microbiota composition and morphology of the small intestine, thereby improving immunity and growth performance without inducing metabolic disorders. The aim of the study was to establish the dosage and time of administration of such a phytobiotic that would have the most beneficial effect on the intestinal histology and microbiota, production results, and immune and metabolic status of broiler chickens. The experiment was carried out on 980 one-day-old male chickens until the age of 42 days. The chickens were assigned to seven experimental groups of 140 birds each (seven replications of 20 individuals each). The control group (G-C) did not receive the phytobiotic. Groups CT-0.05, CT-0.1, and CT-0.25 received the phytobiotic in their drinking water in the amount of 0.05, 0.1, and 0.2 mL/L, respectively, at days 1–42 of life (continuous application, CT). The birds in groups PT-0.05, PT-0.5, and PT-0.25 received the phytobiotic in the same amounts, but only at days 1–7, 15–21, and 29–35 of life (periodic application, PT). Selected antioxidant and biochemical parameters were determined in the blood of the chickens, as well as parameters of immune status and redox status. The morphology of the intestinal epithelium, composition of the microbiome, and production parameters of chickens receiving the phytobiotic in their drinking water were determined as well. The addition of a phytobiotic containing cinnamon oil and citric acid to the drinking water of broiler chickens at a suitable dosage and for a suitable time can beneficially modify the microbiome composition and morphometry of the small intestine (total number of fungi p < 0.001, total number of aerobic bacteria p < 0.001; and total number of coliform bacteria p < 0.001 was decreased) improving the immunity and growth performance of the chickens (there occurred a villi lengthening p = 0.002 and crypts deepening p = 0.003). Among the three tested dosages (0.05, 0.1, and 0.25 mL/L of water) of the preparation containing cinnamon oil, the dosage of 0.25 mL/L of water administered for 42 days proved to be most beneficial. Chickens receiving the phytobiotic in the amount of 0.25 mL/L had better growth performance, which was linked to the beneficial effect of the preparation on the microbiome of the small intestine, metabolism (the HDL level p = 0.017 was increased; and a decreased level of total cholesterol (TC) p = 0.018 and nonesterified fatty acids (NEFA) p = 0.007, LDL p = 0.041, as well as triacylglycerols (TAG) p = 0.014), and immune (the level of lysozyme p = 0.041 was increased, as well as the percentage of phagocytic cells p = 0.034, phagocytosis index p = 0.038, and Ig-A level p = 0.031) and antioxidant system (the level of LOOH p < 0.001, MDA p = 0.002, and the activity of Catalase (CAT) p < 0.001 were decreased, but the level of ferric reducing ability of plasma (FRAP) p = 0.029, glutathione p = 0.045 and vitamin C p = 0.021 were increased).

The Probiotic Lactobacillus fermentum Biocenol CCM 7514 Moderates Campylobacter jejuni-Induced Body Weight Impairment by Improving Gut Morphometry and Regulating Cecal Cytokine Abundance in Broiler Chickens

Simple Summary

High consumption of chicken meat and derived products has been associated with Campylobacter jejuni infections in humans. Probiotics have been exploited successfully with the aim of preventing colonization by unwanted microorganisms in birds. In this research, we investigated the effects of Lactobacillus fermentum Biocenol CCM 7514 supplementation on body weight, morphometry of the intestine and the cecal cytokine response. Probiotic-treated chickens showed higher body weight values than those exposed to C. jejuni or reared under control conditions. These differences in body weight were correlated to the overall characteristics of the small intestine, with larger villi and deeper crypts, observed in chickens administered with L. fermentum; such conditions are known to favor nutrient absorption. Likewise, body weight proved to be correlated to transcript abundance of IL-1β and IL-13. In probiotic-treated birds, such factors were upregulated in comparison to what was detected in C. jejuni-infected chickens; these interleukins are considered crucial in the response to invading pathogens. Clearly, these results show that administration of this probiotic strain lessens the negative effects elicited by C. jejuni and ultimately improves chicken body weight.

Abstract

This research was conducted to investigate if the administration of the probiotic Lactobacillus fermentum could influence body weight, intestinal morphometry and the cecal cytokine response in Campylobacter jejuni-infected chickens. Seventy-two 1-day old COBB 500 male chicks were allocated randomly into four experimental groups. (I) Control group (C), in which chicks were left untreated. (II) LB group, treated with L. fermentum. (III) Cj group, infected with C. jejuni and (IV) coexposure group in which both bacteria were administered. Body weight was registered and then all birds were slaughtered; samples from the small intestine and caecum were collected at 4- and 7-days post infection. The experiment lasted eleven days. Villi height and crypt depth ratios of the duodenum, jejunum and ileum were evaluated using appropriate software, while reverse transcription quantitative PCR (RT-qPCR) was utilized for assessing transcript levels of key cecal inflammatory cytokines (IL-1β, IL-18, IL-17, IL-15, IL13 and IL-4). Campylobacter-infected birds showed lower body weight values than those supplemented with the probiotic; these birds, in turn, proved to be heavier than those reared under control conditions. L. fermentum administration improved morphometrical parameters of the duodenum, jejunum and ileum; in general, villi were larger and crypts deeper than those identified in control conditions. Moreover, the negative effects elicited by C. jejuni were not observed in chickens exposed to the probiotic. Significant differences were also determined with regards to transcript abundance of all evaluated cytokines in the caecum. C. jejuni induced a downregulation of the studied interleukins; however, such a response was heightened by administration of L. fermentum, with an increase rate of transcription that promoted a more effective response to a C. jejuni infection. The effects of experimental treatments proved to vary between sampling points. Conclusively, these results demonstrate that L. fermentum lessens the negative effects elicited by C. jejuni on body weight by alleviating the impact on intestinal morphometry and cecal cytokine response, which ultimately improve chicken growth performance.

Bacterial meta-analysis of chicken cecal microbiota

Poultry production is an industry that generates 90,000 metric tons of chicken meat worldwide. Thus, optimizing chicken growth and sustainable production is of great importance. A central factor determining not only production parameters, but also stability of the immune system and chicken health, is the diversity and variability of the microbiota present throughout the gastrointestinal tract. To date, several studies have investigated the relationship between bacterial communities and the gut microbiome, with limited data to compare. This study aims to create a bacterial meta-analysis based on studies using amplicon sequencing with Illumina sequencing technologies in order to build a baseline for comparison in future analyses of the cecal bacterial composition in chicken. A systematic literature review was performed (SYRF ID: e84f0468-e418-4eec-9da4-b517f1b4809d. Full project URL: https://app.syrf.org.uk/projects/e84f0468-e418-4eec-9da4-b517f1b4809d/detail). From all the available and analyzed manuscripts only nine contained full raw-sequence data available and the corresponding metadata. A total of 324 samples, comprising three different regions within the 16S rRNA gene, were analyzed. Due to the heterogeneity of the data, each region was analyzed independently and an effort for a joint analysis was performed as well. Taxonomic profiling revealed 11 phyla, with Firmicutes as the most prevalent phylum, followed by Bacteroidetes and Proteobacteria. At genus level, 109 genera were found. Shannon metric for alpha diversity showed that factors like type of chickens (Commercial or experimental) and 16S rRNA gene subregion have negligible effect on diversity. Despite the large number of parameters that were taken into account, the identification of common bacteria showed five genera to be common for all sets in at least 50% of the samples. These genera are highly associated to cellulose degradation and short chain fatty acids synthesis. In general, it was possible to identify some commonalities in the bacterial cecal microbial community despite the extensive variability and factors differing from one study to another.

Yellow Mealworm Inclusion in Diets for Heavy-Size Broiler Chickens: Implications for Intestinal Microbiota and Mucin Dynamics

Simple Summary

Nowadays, the maximization of chicken productivity cannot be achieved without considering their gut health, which is a complex, multifactorial concept that takes into account several intestinal features (such as the microbiota and the mucin dynamics). The gut health of broilers may be influenced by both intrinsic (i.e., age, sex, breed) and extrinsic (i.e., diet, environment) factors, thus, in turn, influencing the growth performance of the birds. Dietary insect meal inclusion has already been reported to exert positive effects on cecal microbiota and small intestinal mucin composition in female and male light-size broiler chickens (35–40 days of age), in particular when used at low inclusion levels (i.e., 5%). However, since male heavy-size broilers (50–60 days of age) represents a relevant market class in Italy, we herein evaluated the effects of yellow mealworm (Tenebrio molitor, TM) utilization on their gut health. The findings herein obtained interestingly suggested that the administration of insect meal for a longer period could potentially lead to a negative modulation of the cecal microbiota of the birds, thus suggesting a preferable utilization of yellow mealworm in the light-size production cycles.

Abstract

In the present trial, 160 heavy-size male broiler chickens were allocated to 4 dietary treatments (control feed [C] and 5, 10 and 15% TM meal inclusion, respectively, with 5 replicate pens/treatment and 8 birds/pen) to evaluate the influence of TM meal on intestinal microbiota and mucin composition. The broiler chickens fed TM-based diets showed higher beta diversity of their cecal microbiota in comparison with the C birds (p < 0.001). A significant decrease of the relative abundance of Firmicutes phylum and lower Firmicutes:Bacteroidetes ratios (False Discovery Rate [FDR] < 0.05) were also identified in TM15 broiler chickens when compared to the C group. Furthermore, the TM birds showed decreased relative abundance of Clostridium, Coprococcus, L-Ruminococcus and Ruminococcus genera (FDR < 0.05). In relation to the gut mucin composition, higher mucin staining intensity was detected in the intestinal crypts of TM5 birds in comparison with the other TM groups (p < 0.05). In conclusion, dietary TM meal inclusion negatively influenced the cecal microbiota of heavy-size broiler chickens in terms of partial alteration of the physiological microbial population and reduction of the potential beneficial bacteria (with slightly more pronounced effects when testing the 10–15% inclusion levels).

Poultry feeds carry diverse microbial communities that influence chicken intestinal microbiota colonisation and maturation

Microbial colonisation of the gastrointestinal tract of newly hatched chicks starts at hatch, seeded from the immediate hatching environment, and quickly results in dense colonisation. The role of ecological factors in gut colonisation has been extensively investigated, as well as the role of micro- and macronutrients in supporting and selecting for bacterial species highly adapted for utilising those nutrients. However, the microbial community contained in poultry feed and its influence on colonisation and maturation of gut microbiota has not been directly addressed. In this study, we compared the microbiota found in poultry feed, with the microbiota of ileum, cecum and excreta, to identify substantial overlap in core microbiotas of the compared groups. We then investigated the microbiota present in raw feedstuffs: meat and bone meal, wheat, corn, canola, barley, soybean, millrun, sorghum, poultry oil, oats, limestone and bloodmeal from four geographically distinct feedstuff suppliers. Each of the feedstuffs had diverse microbial communities. The meat and bone meal and bloodmeal samples had the most complex and distinct microbial populations. There was substantial overlap in the phylogenetic composition found in the grain and seed samples: barley, canola, corn, millrun, oats, sorghum, soybean meal and wheat. Issues related to methodology, viability of microbial communities in the gut and feed, and the implications for biosecurity are discussed.

Antimicrobial Effects of Black Soldier Fly and Yellow Mealworm Fats and Their Impact on Gut Microbiota of Growing Rabbits

This study aimed to evaluate the in vitro antimicrobial activities of two types of insect fats extracted from black soldier fly larvae (HI, Hermetia illucens L.) and yellow mealworm larvae (TM, Tenebrio molitor L.) and their effects as dietary replacement of soybean oil (S) on cecal fermentation pattern, and fecal and cecal microbiota in rabbits. A total of 120 weaned rabbits were randomly allotted to three dietary treatments (40 rabbits/group) -a control diet (C diet) containing 1.5% of S and two experimental diets (HI diet (HID) and TM diet (TMD)), where S was totally substituted by HI or TM fats during the whole trial that lasted 41 days. Regarding the in vitro antimicrobial activities, HI and TM fats did not show any effects on Salmonella growth. Yersinia enterocolitica showed significantly lower growth when challenged with HI fats than the controls. The insect fat supplementation in rabbit diets increased the contents of the cecal volatile fatty acids when compared to the control group. A metataxonomic approach was adopted to investigate the shift in the microbial composition as a function of the dietary insect fat supplementation. The microbiota did not show a clear separation as a function of the inclusion, even if a specific microbial signature was observed. Indeed, HI and TM fat supplementation enriched the presence of Akkermansia that was found to be correlated with NH3-N concentration. An increase in Ruminococcus, which can improve the immune response of the host, was also observed. This study confirms the potential of HI and TM fats as antibacterial feed ingredients with a positive influence on the rabbit cecal microbiota, thus supporting the possibility of including HI and TM fats in rabbit diets.

Effects of Vitamin B2 Supplementation in Broilers Microbiota and Metabolome

The study of the microbiome in broiler chickens holds great promise for the development of strategies for health maintenance and performance improvement. Nutritional strategies aimed at modulating the microbiota-host relationship can improve chickens' immunological status and metabolic fitness. Here, we present the results of a pilot trial aimed at analyzing the effects of a nutritional strategy involving vitamin B2 supplementation on the ileum, caeca and litter microbiota of Ross 308 broilers, as well as on the metabolic profile of the caecal content. Three groups of chickens were administered control diets and diets supplemented with two different dosages of vitamin B2. Ileum, caeca, and litter samples were obtained from subgroups of birds at three time points along the productive cycle. Sequencing of the 16S rRNA V3-V4 region and NMR metabolomics were used to explore microbiota composition and the concentration of metabolites of interest, including short-chain fatty acids. Vitamin B2 supplementation significantly modulated caeca microbiota, with the highest dosage being more effective in increasing the abundance of health-promoting bacterial groups, including Bifidobacterium, resulting in boosted production of butyrate, a well-known health-promoting metabolite, in the caeca environment.

Tenebrio molitor Larvae Meal Affects the Cecal Microbiota of Growing Pigs

The hypothesis tested was that dietary inclusion of insect meal (IM) causes an alteration in the cecal microbiota composition and its fermentation activity of growing pigs. Five-week-old male crossbred pigs were randomly assigned to three groups of 10 pigs each, and fed isonitrogenous diets either without (CON) or with 5% IM (IM5) or 10% IM (IM10) from Tenebrio molitor larvae for four weeks. The relative abundance of the phylum Bacteroidetes was lower in group IM10 than in group CON (p < 0.05), whereas the relative abundance of Firmicutes and the Firmicutes:Bacteroidetes-ratio tended to be higher in groups IM10 and IM5 than in group CON (p < 0.1). The relative abundance of the Proteobacteria tended to be higher in group IM10 than in groups CON and IM5 (p < 0.1). The concentrations of the total short-chain fatty acids in the cecal digesta did not differ between the three groups, but the concentrations of the branched-chain fatty acids in the cecal digesta were higher in group IM5 and IM10 than in group CON (p < 0.05). The present study shows for the first time that the replacement of soybean meal by Tenebrio molitor larvae meal causes a shift of the cecal microbial community and its fermentation activity in growing pigs.

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% or 10% HI meal inclusion [HI5 and HI10], with 4 replicate boxes/treatment and 4 animals/box) and slaughtered after 61 days of trial (3 animals/box, 12 piglets/diet). The cecal microbiota assessment by 16S rRNA 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.

Sanguinarine modulate gut microbiome and intestinal morphology to enhance growth performance in broilers

Sanguinarine is a bioactive compound as a quaternary benzophenanthridine alkaloid from plant of the Macleaya cordata, Papaveraceae family. The present study was conducted to investigate the effects of dietary sanguinarine supplementation on growth performance, serum biochemistry parameters, intestinal mucosal morphology and gut microbiome in yellow feathered broilers. Two hundred and seventy 1-d-old female broilers were randomly assigned to 3 treatments ① Basal diet (NG); ② Basal diet containing bacitracin methylene disalicylate (50mg/Kg diet) (ANT); ③ Basal diet containing sanguinarine (0.7 mg/ kg of feed) (SAG). The statistical results showed that dietary sanguinarine supplementation enhanced growth performance and decreased glucose, uric acid as well as urea nitrogen levels of broilers at 28d of age (P<0.05). The 16S rRNA gene sequence analysis revealed that sanguinarine significantly decreased the species from the phyla Bacteroidetes, and increased the species from phyla Firmicutes. Moreover, dietary sanguinarine supplementation improved mucosal morphology to achieve higher ratio of intestinal villus height to crypt depth (P < 0.05), and decreased the concentrations of TNF-α and IL-4 in jejunum mucosal. This study demonstrated that sanguinarine supplementation in the diet of yellow feathered broilers improved intestinal morphology and microbiota community structure to promote growth performance on 1-28d.

Effect of chronic cyclic heat stress on the intestinal morphology, oxidative status and cecal bacterial communities in broilers

The objective of this study was to examine the effects of chronic cyclic heat stress (HS) on the intestinal morphology, oxidative stress and cecal bacterial communities of broilers. One-day-old Arbor Acres (AA) male broilers (n = 100) were acclimated for 3 weeks and then randomly allocated into two groups, normal control (NC) group (22 ± 1 °C, 24 h/day) and HS group (32 ± 1 °C, 10 h/day lasted for 2 weeks). At 35 d of age, intestinal segments (duodenum, jejunum and ileum) and cecal digesta were collected for detection. HS affected intestinal morphology, inducing epithelial cell abscission, inflammatory cell infiltration, and lamina propria edema. Compared with the NC group, HS significantly decreased (P < 0.01) villus height (VH) and the VH-to-crypt depth (CD) ratio (VCR), increased (P < 0.05) CD in the duodenum and ileum, but had no effect on the VH in the jejunum. Moreover, HS induced oxidative stress with antioxidant enzymes activity decreasing (P < 0.05) while malondialdehyde (MDA) content increasing (P < 0.05) in small intestine. Pearson's correlation analysis indicated that MDA content was negatively correlated with VH (P < 0.05). The result of 16S rRNA sequencing showed that HS exposure impacted cecal microbiota alpha diversity (phylogenetic diversity whole-tree index) and beta diversity. Based on principal coordinate analysis (PCoA) plots for weighted UniFrac metrics and unweighted pair group method with arithmetic mean (UPGMA), there were 8 discriminative features at the genus level (linear discriminant analysis score > 2). Parabacteroides, Saccharimonas, Romboutsia and Weissella were reduced, while Anaerofustis, Pseudonocardia, Rikenella and Tyzzerella were enriched in heat-stressed broilers. Collectively, these results indicated that chronic cyclic HS induced oxidative stress that caused damage to intestinal villus-crypt structures, and then altered the cecal microflora profile.

Cloacal Swabs Are Unreliable Sources for Estimating Lower Gastro-Intestinal Tract Microbiota Membership and Structure in Broiler Chickens

The gastrointestinal microbiota of chickens plays a central role in health and performance. Cloacal swabs, due to their proximity to the ceca (a vital site of functional activity), are an alternative, non-invasive method used for assaying microbial communities and might be a viable option for longitudinal studies. In this study, the microbiota of twenty paired cecal content and cloacal swab samples representing two dietary treatments was assessed using 16S rRNA V4 hypervariable region sequencing and was analyzed using the MOTHUR pipeline, Phyloseq, and Vegan packages. Paired t-test and Wilcoxon signed-rank tests showed significant differences in the Chao1 index (p-value <0.0001 and p-value <0.0001, respectively) but not in the Inverse Simpson species diversity estimator (p-value = 0.06763 and p-value = 0.06021, respectively) between the cecal content and cloacal swabs. β-diversity between the cloacal swabs and cecal microbiota also showed significant differences using PERMANOVA, HOMOVA, and weighted UniFrac testing (p-values < 0.001). Based on a paired sample analysis, this study provided evidence of the high inter-individual variation and randomness of cloacal microbiota, in contrast to cecal microbiota. Our findings indicated that cloacal swabs do not approximate the α or β diversity of cecal samples and are not suitable for longitudinal studies of gut microbiota.

Evaluation of in ovo Bacillus spp. based probiotic administration on horizontal transmission of virulent Escherichia coli in neonatal broiler chickens

This study evaluated the effect of in ovo Bacillus spp. base probiotic (BBP) administration on hatchability, Gram-negative bacteria (GNB) recovery, performance, and microbiota composition in 2 independent trials using a virulent E. coli seeder challenge model. In each trial, one hundred and eighty 18-day-old embryos were allocated into 1 of 2 groups: Control and treated group (inoculated with 107 BBP). On day 19 of embryogenesis, seeder embryos (n = 18) were inoculated with 4.5 × 104E. coli/mL+272 μg/mL tetracycline and segregated into mesh hatching bags. Twelve chicks per group were euthanized at hatch and at day 7 to evaluate the gastrointestinal composition of total GNB or total aerobic pasteurized bacteria. Also, in trial 2, ceca content from five chickens at day 7 were collected to evaluate microbiota composition. Embryos inoculated with BBP showed a significant (P < 0.05) reduction in the total number of GNB at day-of-hatch (DOH) and day 7. Probiotic treatment increased BW at DOH and day 7, and BW gain (days 0 to 7) when compared with Control chickens. Proteobacteria phylum was significantly reduced, while the Firmicutes was significantly increased by the BBP as compared to the Control (P < 0.05). At family level, Enterobacteriaceae was significantly decreased, while the Lachnospiraceae was significantly elevated in the BBP as compared to the Control group (P < 0.05). The genus Oscillospira was significantly enriched in the BBP group, whereas the unidentified genus of family Enterobacteriaceae in the Control group (P < 0.05). The BBP group increased the bacterial species richness, although there was no significant difference between treatments (P > 0.05). Interestingly, beta diversity showed a significant difference in bacterial community structure between Control and BBP groups (P < 0.05). The results of the present study suggest that in ovo administration of a BBP can reduce the severity of virulent E. coli horizontal transmission and infection of broiler chickens during hatch. The reduction in the severity of the transmission and infection by the BPP might be achieved through alterations of microbiota composition and its community structure.

Improvement of Cecal Commensal Microbiome Following the Insect Additive into Chicken Diet

Gastrointestinal microbiota play an important role in regulating the metabolic processes of animals and humans. A properly balanced cecal microbiota modulates growth parameters and the risk of infections. The study examined the effect of the addition of 0.2% and 0.3% of Tenebrio molitor and Zophobas morio on cecal microbiome of broilers. The material was the cecum digesta. The obtained DNA was analyzed using 16S rRNA next generation sequencing. The results of the study show that the addition of a relatively small amount of Z. morio and T. molitor modulates the broiler cecum microbiome composition. The most positive effect on cecal microbiota was recorded in the 0.2% Z. morio diet. A significant increase in the relative amount of genus Lactobacillus, represented by the species Lactobacillus agilis and the amount of bacteria in the Clostridia class, was observed. Moreover, the addition of 0.2% ZM resulted in a significant increase of relative abundance of the family Bifidobacteriaceae with the highest relative abundance of genus Bifidobacterium pseudolongum. The obtained results indicate that the addition of a relatively small amount of insect meal in broiler diet stimulates colonization by probiotic and commensal bacteria, which may act as barriers against infection by pathogenic bacteria.

Fluoride-induced rectal barrier damage and microflora disorder in mice

Intestinal microflora plays a key role in maintaining the homeostasis between immune and host health. Here, we reported the fluoride-induced changes of rectal structure and microflora in mice. The morphology of rectal tissue was observed by hematoxylin and eosin staining. The rectal development parameters (the thickness of mucosa, intestinal gland and muscle layer) were evaluated. The proliferation of rectal epithelial cells was evaluated via BrdU labeling. The distribution of goblet, glycoprotein and mast cell were evaluated by specific staining. Rectal microflora was detected using 16S rRNA high-throughput sequencing. The results showed that the rectal structure was seriously damaged and the proliferation of rectal epithelial cells was significantly inhibited by fluoride. The distribution of goblet cells, glycoprotein and mast cells decreased significantly after fluoride exposure. The relative richness of microfloras was changed after fluoride treatment, such as increased Bacteroidetes and decreased Firmicutes. In summary, this study indicated that excessive fluoride damages the intestinal structure, disturbs the intestinal micro-ecology and causes intestinal microflora disorder in mice. Findings mentioned in the present study enrich a new scope for elucidating fluoride toxicity from intestinal homeostasis.

Effects of Lactobacillus plantarum on intestinal integrity and immune responses of egg-laying chickens infected with Clostridium perfringens under the free-range or the specific pathogen free environment

Background

Necrotic enteritis, which is caused by Clostridium perfringens, has resulted in more than $2 billion losses in the poultry industry every year. Due to the ban of antibiotics in feed industry, alternatives like environment improvement and probiotics have been found to be effective as well. In our study, we aim to explore the protective effect of Lactobacillus plantarum supplementation on CP infected chickens in two environments.

Results

The results showed that the Clostridium perfringens administration led to visible and histomorphological gut lesions. In the specific pathogen free or free-range system environment, dietary supplementation with LP obvious increased the ratio of intestinal villus height to crypt depth and the expression of MUC2 mRNA in ileum mucosa, then reduced the mRNA expression level of TNF-α gene in the ileum mucosa. LP treatment significantly reduced the contents of total protein, total superoxide dismutase and glutamic oxaloacetic transaminase in serum of the chickens.

Conclusions

The specific pathogen free environment contributed to the recovery of pre-inflammation of the chickens, and free-range system environment contributed to the repair of damage in the later stages of chicken inflammation. Supplementation of LP in FRS environment was more conducive to the recovery of CP infected in chickens.

Degeneration of the intestinal microbial community in PI3Kγ-knockout mice

BACKGROUND AND AIM

PI3Kγ is closely related to inflammation and cardiovascular diseases and thus, PI3Kγ inhibitors are candidate drugs for the treatment of these disorders. Considering the potential effect of the intestinal microbiome on inflammation and cardiovascular diseases, this study aimed to identify characteristics of the intestinal microbial community under PI3Kγ deficiency, to help reveal the potential influence of PI3Kγ inhibitors mediated by the microbial community.

METHODS

Exon 2 of the PI3Kγ gene was knocked out in a Balb/c mouse by using single-guide RNAs. Homozygous PI3Kγ-knockout (PI3Kγ-/-) mice were obtained by embryo transfer and hybridization. PI3Kγ-/- and wild-type (WT) mice were raised in the same specific pathogen-free conditions until 8 weeks of age. Then, colonic tissues and feces from the middle segment of the colon were collected and analyzed by Illumina MiSeq sequencing. Differences in intestinal microbial community between the PI3Kγ-/- and WT mice were detected by bioinformatics analysis.

RESULTS

The richness and alpha diversity of the colonic microbial community were decreased in PI3Kγ-/- mice. The alpha diversity of the microbial community in feces did not differ between PI3Kγ-/- and WT mice. The beta diversity of the microbial community in feces of PI3Kγ-/- mice was obviously different from that in WT mice, whereas the within-group variation in Bray-Curtis distances of the mucosal microbial community was significantly decreased in PI3Kγ-/- mice. The topological structure of the species-related network of the colonic microbial community in PI3Kγ-/- mice was more polarized. Finally, we predicted that PI3Kγ deficiency might affect the synthesis of some antibiotics, bile acid, and thiamine through effects on the microbial community.

CONCLUSIONS

PI3Kγ dysfunction led to degeneration of the intestinal microbial community and might alter the synthesis of some antibiotics, bile acids, and thiamine. The usage of PI3Kγ inhibitors for inflammation and cardiovascular diseases might lead to knock-on effect on our organism through intestinal microbiota.

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.

Replacement of soybean oil by Hermetia illucens fat in turkey nutrition: effect on performance, digestibility, microbial community, immune and physiological status and final product quality

1. The aim of the present study was to investigate the effect of partial (50%) or total replacement of soybean oil (SO) by black soldier fly larvae (BSFL) fat on the growth performance, coefficients of apparent nutrient digestibility, selected internal organ weights and length, pancreatic enzyme activity and gastrointestinal tract (GIT) microecology modulation, as well as microbiota activity, physiological and immunological responses in young turkey poults. 2. A total of 216, seven day old female turkeys (B.U.T 6) were randomly distributed to three dietary treatments using six replicate pens per group with 12 birds per pen. The following design of the trial was applied: SO 100% soybean oil; BSFL50 a 50/50 combination of SO and BSFL fat; or 100% BSFL fat (total replacement of SO). 3. The use of BSFL fat did not affect the growth performance, nutrient digestibility, GIT morphology, or quality of the breast and thigh muscles. However, reduced trypsin activity was noticed in the BSFL100 group, but this had no effect on digestibility. Total replacement of SO reduced proliferation of potentially pathogenic bacteria, i.e., Enterobacteriaceae spp., as well as decreasing levels of IL-6, while partial substitution lowered the TNF-α concentration. 4. The replacement of commonly used SO by BSFL fat can be successfully applied in young turkey poult nutrition. BSFL fat may be considered an antimicrobial agent and support immune responses.

Tenebrio molitor and Zophobas morio Full-Fat Meals in Broiler Chicken Diets: Effects on Nutrients Digestibility, Digestive Enzyme Activities, and Cecal Microbiome

This study was conducted to investigate the effect of insect full-fat meals added in relatively small amounts to a complete diet on the coefficients of apparent ileal digestibility, short-chain fatty acid (SCFA) concentrations, bacterial enzymes, and the microbiota community in the cecal digesta of broiler chickens. In total, 600 one-day-old female Ross 308 broiler chicks were randomly assigned to six dietary treatments with 10 replicate pens/treatment and 10 birds/pen. The groups consisted of a negative control (NC) with no additives; a positive control (PC; salinomycin 60 ppm), and supplementation with 0.2% or 0.3% Tenebrio molitor or Zophobas morio full-fat meals. Z. morio (0.2%) addition increased the activities of α- and β-glucosidase and α-galactosidase. Dietary insects significantly decreased the cecal counts of the Bacteroides-Prevotella cluster in comparison to those in the NC and PC. Whereas, Clostridium perfringens counts were increased in the broiler chickens subjected to the 0.3% Z. morio treatment. In conclusion, small amounts of full-fat insect meals added to broiler diets were capable of reducing the abundance of potentially pathogenic bacteria, such as the Bacteroides-Prevotella cluster and Clostridium perfringens. In addition, this supplementation was able to stimulate the GIT microbiome to produce enzymes, especially glycolytic enzymes.

Intestinal barrier damage involved in intestinal microflora changes in fluoride-induced mice

Intestinal microflora play an important role in maintaining the homeostasis of the intestinal microenvironment, but fluoride-induced changes in intestinal mechanical barrier and intestinal microflora have not been well studied. Given this paucity of information, this study aims to determine the effects of high fluoride level on intestinal mechanical barrier and intestinal microflora in the cecum of mice. Seventy-two female 21-day-old Kunming mice were randomly assigned to three groups and raised for 70 days. Changes in intestinal pathomorphology and intestinal epithelial cell proliferation were observed by haematoxylin and eosin-staining and Brdu measurement, respectively. The distribution of goblet cells, glycoproteins and mast cells was analysed through Alcian blue and periodic acid-Schiff (AB-PAS) staining, Periodic Acid-Schiff (PAS) staining, and toluidine blue staining. Results showed that excessive fluoride damaged the structure of the cecal tissues, inhibited epithelial cell proliferation and decreased the relative distribution of goblet cells, glycoproteins and mast cells that are involved in defense responses. Intestinal microflora sequencing analysis revealed that the composition of the diversity and composition of intestinal microflora was altered by excessive fluoride based on 16S rRNA amplicon sequencing. The relative abundance of Firmicutes (P = 0.03174), Bacteroidetes (P = 0.04462), Actinobacteria (P = 0.01085) and Spirochacteria (P = 0.04084) was significantly changed in the fluoride group as compared with the control group. In conclusion, excessive fluoride intake induced intestinal barrier damage, leading to changes in cecal composition, epithelium secretion and intestinal microflora.

Effects of insect diets on the gastrointestinal tract health and growth performance of Siberian sturgeon (Acipenser baerii Brandt, 1869)

Background

Insects in the fish diet are a natural source of protein, fat, and other nutrients. These meals are considered an ecological replacement for fishmeal to improve growth parameters. The application of insect meals to fish diets has been studied, especially in continental fish. Data regarding the effects of insect meals on the gut health of Siberian sturgeon are not available. This study investigated the effects of full-fat Hermetia illucens (HI) and Tenebrio molitor (TM) meals on the gut health of juvenile Siberian sturgeon. Growth performance, gastrointestinal tract (GIT) histomorphology and the microbiome composition of juvenile Siberian sturgeon were analyzed.

Results

The inclusion of insect meals did not affect the growth performance or the survival rate. In the gastrointestinal tract histomorphology, a reduction in the mucosa thickness with the HI treatment was observed. In contrast, fish fed the TM diet had an increase in the thickness of the muscular layer. There were no observed significant differences in villus height among treatments. The analysis of the selected microbiota populations in the Siberian sturgeon gastrointestinal tract showed that insect addition affected the composition of the microbiome. The greatest effect on bacterial populations (Clostridium leptum subgroup, Enterobacteriaceae, Clostridium coccoides – Eubacterium rectale cluster, Aeromonas spp., Bacillus spp., Carnobacterium spp., Enterococcus spp. and Lactobacillus group) was observed with the HI diet (P < 0.05). The TM-based diet increased counts in the following bacterial groups: Clostridium coccoides – Eubacterium rectale cluster, Bacillus spp., Carnobacterium spp., and Enterococcus spp. In contrast, the TM diet decreased the total number of bacteria. The TM diet did not significantly affect the Clostridium leptum subgroup, Enterobacteriaceae, Aeromonas spp. or the Lactobacillus group.

Conclusions

Fish meal replacement by the inclusion of 15% of full-fat Hermetia illucens and Tenebrio molitor (15%) meals did not affect the growth performance, survival rate or villus height of juvenile Siberian sturgeon. The present study suggests that an H. illucens-based diet positively affects the gut microbiota composition and intestinal morphology of juvenile Siberian sturgeon without negative changes in the villus height.

A Glimpse into the Microbiota of Marketed Ready-to-Eat Crickets (Acheta domesticus)

The present study was aimed to get an insight into the bacterial biota of ready-to-eat small crickets (Acheta domesticus) already marketed in the European Union. 16S rRNA gene of the DNAs extracted from thirty-two samples of ready-to-eat crickets commercialized by 4 European Union producers located in Austria, Belgium, France and the Netherlands (2 batches per producer) was analyzed by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). The species belonging to the genera Hespellia, Ruminococcus and Clostridium were detected in samples from Austria, while those from genera Lysobacter, Staphylococcus and Clostridium were detected in samples from Belgium. Moreover, samples from France were characterized by Staphylococcus, Pseudomonas, and Hydrogenophilus genera. Finally, the genera Staphylococcus, Hydrogenophilus, Clostridium and Ruminococcus were identified in the samples produced in the Netherlands. When insects are intended for commercialization, rearing, processing and handling could affect the presence of the occurring microbial species. Hence, to assure a safe product, the need for a full standardization of production technologies, including feed supply as well as rearing and processing practices, is recommended.

Effects of the Dietary Inclusion of Partially Defatted Black Soldier Fly (Hermetia illucens) Meal on the Blood Chemistry and Tissue (Spleen, Liver, Thymus, and Bursa of Fabricius) Histology of Muscovy Ducks (Cairina moschata domestica)

Simple Summary

Insects represent a promising feed ingredient for poultry diets, as an alternative to conventional feedstuffs. Black soldier fly (BSF; Hermetia illucens) larvae are processed to obtain two main products: the protein and fat fractions. The possible utilization of BSF defatted meal in Muscovy duck (Cairina moschata domestica) diets has been poorly investigated. However, its effect on in vivo and post-mortem traits, which are extremely important for animal welfare, has not yet been investigated. Therefore, the present study has evaluated the effect of 0%, 3%, 6%, and 9% dietary BSF meal replacement on the in vivo haematological parameters and on the post-mortem organ traits. Overall, the obtained results are encouraging as increasing dietary BSF meal did not impair the growth performance or the haematological traits. Furthermore, both the liver and renal function were unaffected or even improved. The antioxidant picture appeared improved and the histological traits were not influenced by the dietary inclusion of BSF meal. From a productive and biological point of view, the dietary replacement up to 9% of BSF meal in Muscovy duck diet is feasible and BSF meal could represent a promising feed ingredient.

Abstract

The present study has evaluated the effects of dietary partially-defatted black soldier fly (BSF; Hermetia illucens L.) larva meal on the blood parameters, antioxidant status, and histological features of the organs of broiler ducks. A total of 192 female 3-days of age Muscovy ducklings (Cairina moschata domestica) were divided into four dietary treatments (0%, 3%, 6%, and 9% BSF meal inclusion; 6 pens/treatment, 8 birds/pen). A total of 12 ducks/treatment (2 birds/pen) were slaughtered at 51 days of age and blood samples were collected to evaluate the haematological traits, serum protein, lipid and minerals, liver and renal function serum enzymes, plasma oxidative enzymes, and metabolites. Liver, spleen, thymus, and bursa of Fabricius samples were submitted to histopathological investigations. Between the serum and plasma traits, triglycerides, cholesterol, creatinine, alkaline phosphatase, magnesium, malondialdehyde, and nitrotyrosine showed a linear decrease for increasing amounts of dietary BSF meal (p <0.01); in contrast, the serum iron concentration showed a linear increase (p <0.01). Moreover, the histopathological findings were not significantly affected by the dietary BSF larva meal inclusion. The results showed that the inclusion of up to 9% BSF larva meal represents a promising feed ingredient for Muscovy duck nutrition, and improved blood traits were observed.

Nutritional effects of the dietary inclusion of partially defatted Hermetia illucens larva meal in Muscovy duck

Background

The present work is aimed at evaluating the effect of different inclusion levels of a partially defatted black soldier fly (Hermetia illucens, L.; HI) larva meal for ducks. A total of 192 female 3-day-old Muscovy ducklings (Cairina moschata domestica, Canedins R71 L White, Grimaud Freres Selection, France) were divided into 4 groups, assigned 4 different dietary treatments (6 replicates/treatment and 8 birds/replicate) and reared from 3 to 50 days of age. HI larva meal was included at increasing levels (0, 3%, 6% and 9%, HI0, HI3, HI6 and HI9, respectively) in isonitrogenous and isoenergetic diets formulated for 3 feeding phases: starter (3–17 days of age), grower (18–38 days of age) and finisher (39–50 days of age). The growth performance and apparent total tract digestibility were evaluated during the trial using titanium dioxide as an inert marker (0.3% of inclusion). At 51 days of age, two birds per pen were slaughtered and histomorphological investigations were performed.

Results

The live weight and average daily gain showed a quadratic response to increasing HI meal in the grower period (minimum corresponding to the HI6 group). No effects of dietary inclusion levels were observed for the daily feed intake or feed conversion ratio. The apparent dry matter and organic matter digestibility were not affected by the dietary treatment. A linear decrease was observed for the crude protein apparent digestibility in the starter period (minimum for the HI9 groups). The ether extract apparent digestibility increased linearly during the grower and finisher periods (minimum for the HI0 group). The morphometric indices were not influenced by the dietary treatments.

Conclusions

The inclusion of up to 9% of HI partially defatted larva meal in the diet of ducks did not cause any effect on growth performance, as well as the apparent digestibility. Moreover, dietary HI inclusion preserved the physiological intestinal development.

Gut Microbiota and Mucin Composition in Female Broiler Chickens Fed Diets including Yellow Mealworm (Tenebrio molitor, L.)

A total of 160 female broiler chickens were divided into four dietary treatments (control feed [C] and 5, 10 and 15% TM meal inclusion, respectively, with five replicate pens/treatment and eight birds/pen) to investigate the effects of Tenebrio molitor (TM) meal utilization on poultry gut microbiota and mucin composition. The cecal microbiota assessment displayed a shift in the beta diversity in chickens fed TM-based diets. The TM10 and TM15 birds showed a significant decrease in the relative abundance of Firmicutes phylum and lower Firmicutes:Bacteroidetes ratios (False Discovery Rate [FDR] < 0.05), respectively, than the TM5 group. The relative abundance of Clostridium, Alistipes and Sutterella genera significantly increased in TM chickens (FDR < 0.05), while birds fed TM-based diets displayed a significant decrease in the relative abundance of Ruminococcus genus in comparison with the C group (FDR < 0.05). Gut mucin composition evaluation revealed higher mucin staining intensity in the intestinal villi of TM5 birds than the other TM groups, as well as mucin reduction in the intestinal villi of TM10 birds when compared to the C group (p < 0.05). In conclusion, dietary TM meal utilization (especially the 10-15% inclusion levels) may negatively influence either the cecal microbiota or the intestinal mucin dynamics of broiler chickens.

A Meta-Analysis of the Effects of Insects in Feed on Poultry Growth Performances

Simple Summary

Today, insects are receiving great attention as a potential source of poultry feed and the number of experiences is exploding. However, it is difficult to obtain an evidence-based view from this large volume of and large diversity of information. A meta-analysis is the best method to summarize the findings of all these studies. Thus, we searched all recent studies that explore the effects of insects in feed on the growth performances of poultry species. Results showed that insects in feed do not modify performances if they substitute less than 10% of conventional protein sources and are not grasshoppers.

Abstract

We investigated and summarized results from studies evaluating the effects of feeding poultry with insects on their growth performances. After a systematic review of studies published since 2000, two independent reviewers assessed the eligibility of each one based on predefined inclusion criteria. We extracted information on the study design, insects, avian species, and growth performances, i.e., average daily gain, feed intake, and feed conversion ratio. Next, we estimated pooled differences between performances of poultry fed a diet with vs. without insects through random-effects meta-analysis models. Additionally, these models evaluated the effects of potential sources of heterogeneity across studies. Of the 75 studies reviewed, 41 met the inclusion criteria and included 174 trials. With respect to diets without insects, pooled differences in growth performances were statistically not different from the null, but heterogeneity was marked across studies. Average daily gain decreased with increasing inclusion rates of insects, going below the null for rates of 10% and more. Grasshoppers were negatively associated with the average daily gain and positively associated with feed intake. The country of publication was another source of heterogeneity across publications. Overall, our results show insects should substitute only partially conventional protein sources and not be grasshoppers to guarantee the appropriate growth of birds.