Insect-based diet, a promising nutritional source, modulates gut microbiota composition and SCFAs production in laying hens

Luca Borrelli,Francesca Lembo,Alessandro Fioretti,Antonio Nizza,Fulvia Bovera,Lorenzo Chiariotti,Ludovico Dipineto,Francesca Menna,Lorena Coretti

doi:10.1038/s41598-017-16560-6

Abstract

Insects could be potential nutritional sources both for humans and animals. Among these, Hermetia illucens, with good amount of chitin and proteins, represents a suitable diet replacement for laying hens. Little is known about insect diet effects on the microbial ecology of the gastrointestinal tract and bacterial metabolites production. In this study we investigated the effect of H. illucens larvae meal administration on cecal microbiota and short chain fatty acids (SCFAs) production in laying hens. 16S rDNA sequencing showed strong differences between cecal microbiota of soybean (SD) and insect diet (ID) groups both in type and relative abundance (unweighted and weighted beta diversity) of microbial species. In particular, Bacteroides plebeius, Elusimicrobium minutum, Alkaliphilus transvaalensis, Christensenella minuta, Vallitalea guaymasensis and Flavonifractor plautii represented the principal contributors of changes in gut microbiota composition of ID group (FDR p-values < 0.05). Of these, F. plautii, C. minuta and A. transvaalensis have the potential to degrade the chitin’s insect meal and correlated with the observed high levels of gut SCFAs produced in ID group. These microorganisms may thus connect the chitin degradation with high SCFAs production. Our results suggest H. illucens as a potential prebiotic by well feeding gut microbiota.

Highlights

Linneus in the 1735 work Systema Naturae wrote: “Larvae assate in deliciis habentur” [roasted larvae are delicious] describing the larvae of Rynchophorous spp
We deep sequenced the gut bacterial community and evaluated the short chain fatty acids (SCFAs) concentrations to assess the effect of H. illucens larvae meal administration in laying hens
After 21 weeks of soybean and insect meal administration (SD and insect diet (ID) groups, respectively), all birds were clinically healthy, neither mortality or diarrhea or sickness signs were observed in the 2 groups throughout the entire experiment, indicating that H. illucens had no negative effects on laying hen health status as reported in the same experimental design previously published[18] (Table 1)

Summary

Introduction

Linneus in the 1735 work Systema Naturae wrote: “Larvae assate in deliciis habentur” [roasted larvae are delicious] describing the larvae of Rynchophorous spp. As a component of a complete diet, H. illucens prepupae have been found to support good growth in chickens and other animals[3,5,6,7,8] These larvae have natural antibiotics property modifying the microflora of manure, potentially reducing harmful bacteria, such as Escherichia coli 0157:H7 and Salmonella enterica in hen manure[9,10]. Marono et al (2017) observed that H. illucens larvae administration has good effects on laying hen health status, reducing serum and eggs cholesterol and triglycerides levels[18] These beneficial effects may be due to the chitin amount provided by diet. We hypothesized in this study that insect-based diet might modulates the gut microbiota and its principal metabolites, improving the health status in laying hens To this aim, we deep sequenced the gut bacterial community and evaluated the SCFAs concentrations to assess the effect of H. illucens larvae meal administration in laying hens

Methods

Results

Discussion

Conclusion