# Nutritional Evaluation of Housefly Larvae Meal in Broilers: Growth Performance, Gut Health, Metabolic Energy, and Microbiota Composition

## TL;DR

This study shows that housefly larvae meal can replace fish meal in broiler diets without harming growth and may even improve gut health and digestion.

## Contribution

The study demonstrates that housefly larvae meal is a viable and sustainable alternative to fish meal in broiler diets.

## Key findings

- Housefly larvae meal maintained growth performance and improved intestinal morphology in broilers.
- HL reduced inflammation and enhanced protein utilization in broiler chickens.
- HL altered gut microbiota composition and metabolic pathways in a beneficial way.

## Abstract

Fish meal (FM) is the most expensive ingredient in livestock feed owing to its relative scarcity and nutritional value. Recent research has shown that insects possess potential as sustainable and cost-efficient alternatives to FM in livestock nutrition. However, extensive research is necessary to identify suitable insect species; their optimal inclusion levels; and their effects on the growth performance, feed digestibility, and overall health of poultry species. In this study, we examined the effects of replacing FM with housefly larvae (HL) at levels of up to 5% on the growth performance, gut health, and overall health of broiler chickens. HL addition effectively maintained growth, improved intestinal morphology, reduced inflammation, enhanced protein utilization, and induced considerable changes in the gut microbiota community. Overall, this study highlights the potential of HL as a suitable replacement for FM in broiler diet.

Poultry production faces considerable challenges in terms of feed costs and sustainability, particularly regarding conventional protein sources such as fish meal (FM). Insect-based proteins, such as housefly larvae (HL) meal, offer sustainable alternatives. Therefore, this study aimed to investigate the effects of HL on growth, gut health, metabolizable energy, and gut microbiota of broilers to clarify the availability of HL meal for broiler diet. Experiment 1 was performed to investigate the effects of replacing FM with HL on growth performance, intestinal morphology, cecal short-chain fatty acids, and gut microbiota composition and diversity in male broilers. Experiment 2 was performed to assess the digestibility of broiler diets containing HL. HL addition effectively maintained growth and improved intestinal morphology. Blood analysis revealed that HL addition reduced TNF-α levels and improved protein utilization. Additionally, HL substitution induced significant changes in the gut microbiota community and metabolic pathways. In conclusion, HL are a viable alternative to FM with adequate energy content and beneficial effects on gut health, supporting their use as a sustainable protein source.