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

Abstract

BackgroundGut health in poultry depends on the balance between the host, intestinal microbiota, intestinal microscopic features and diet. The effects of insect meal (a promising alternative protein source for poultry feed) on chicken gut morphology have recently been reported, but no data about intestinal microbiota and mucin composition modulation are available. The present study evaluated the effects of dietary Tenebrio molitor (TM) meal inclusion on gut health of free-range chickens by intestinal microbiota, morphology and mucin composition characterization.ResultsOne hundred forty female medium-growing hybrids were divided into 2 dietary treatments (control feed [C] and 7.5% TM inclusion, with 5 replicate pens/treatment and 14 birds/pen) and slaughtered at 97 days of age (2 birds/pen for a total of 10 chickens/diet). The gut microbiota assessment on cecal content samples by 16S rRNA amplicon based sequencing showed higher alpha (Shannon, P < 0.05) and beta (Adonis and ANOSIM, P < 0.001) diversity in birds fed TM diet than C. In comparison with C group, TM birds displayed significant increase and decrease, respectively, of the relative abundances of Firmicutes and Bacteroidetes phyla, with higher Firmicutes:Bacteroidetes ratios (False Discovery Rate [FDR] < 0.05). The relative abundance of Clostridium, Oscillospira, Ruminococcus, Coprococcus and Sutterella genera was higher in TM chickens than C (FDR < 0.05). On the contrary, TM birds displayed significant decrease of the relative abundance of Bacteroides genus compared to the C group (FDR < 0.05). Gut morphology evaluation by morphometric analysis on small intestine revealed similar villus height, crypt depth and villus height to crypt depth ratio between C and TM birds. Characterization of gut mucin composition by periodic-acid Schiff, Alcian Blue pH 2.5 and high iron diamine staining on small and large intestine showed unaffected mucin staining intensity in TM chickens when compared to C group.ConclusionsDietary TM meal inclusion may positively modulate the gut microbiota of the free-range chickens without influencing the intestinal morphology and mucin composition. Since the rapid growth of chickens directly depends on morphological and functional integrity of the digestive tract, the gut health assessment by a post mortem multidisciplinary approach appears to be fundamental.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1690-y) contains supplementary material, which is available to authorized users.

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

“…The replacement of soybean meal with insect meal as a source of protein has been reported to modulate the GIT microbiota population in broiler chickens and laying hens [15][16][17][18][19][20]. Our findings using insects as feed additives did not show any effects on the total number of bacteria.…”

“…These results are in agreement with a study conducted by Józefiak et al [20], in which the Bacteroides-Prevotella cluster level was lowered with the inclusion of 0.2% T. molitor full-fat meal. Furthermore, Biasato et al [15] found that Bacteroides abundance was lowered in the ceca of broilers fed diets in which soybean meal was replaced by T. molitor meal. The reduction in Bacteroides abundance in the cecal content of the broiler chickens fed insect full-fat meal in the current study may be considered a potential positive effect.…”

“…Recently, insects have been proposed as an alternative source of protein and fat for broilers, turkeys and laying hens [10][11][12][13][14]. In addition, insects were found to be one of the nutrient factors that can modulate the GIT microbiota populations during full or partial replacement of protein sources [15][16][17][18][19] and as feed additives in the diet of broiler chickens [20]. This microbiota modulation can be achieved through bioactive compounds that are present in insects, i.e., chitin, and antimicrobial peptides (AMPs) [16,20].…”

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

“…Gut microbiota can affect intestinal morphology through modifications of villus height and crypt depth [4]. CP can directly damage intestinal mucosa, alter intestinal microflora, or damage the immune system [41].…”

Histopathological Alterations of Ceca in Broiler Chickens (Gallus gallus) Exposed to Chronic Heat Stress.

“…Likewise, it is known that poultry are very likely to develop acclimatization when kept under tropical and subtropical climates with over two months of high temperature (He et al, 2018). Therefore, it can be deduced that the chickens in this study did not need deep crypts in their ceca to preserve their villi from potential casualties because they had created such an effective mechanism enabling them to withstand the lengthy HS (Biasato et al, 2018).…”