Effect of moisture content on larval gut microbiome and the conversion of pig manure by black soldier fly

Lili Wang; Shengwen Wang; Rencan Yang; Bin Zhang; Le Xu; Qingquan Hu; Zhiyong Zhao; Zhenhui Cao

doi:10.1016/j.scitotenv.2023.169579

Effect of moisture content on larval gut microbiome and the conversion of pig manure by black soldier fly

Sci Total Environ. 2024 Feb 20:912:169579. doi: 10.1016/j.scitotenv.2023.169579. Epub 2023 Dec 23.

Authors

Lili Wang¹, Shengwen Wang², Rencan Yang³, Bin Zhang³, Le Xu², Qingquan Hu³, Zhiyong Zhao⁴, Zhenhui Cao⁵

Affiliations

¹ MOE Key Laboratory of Bio-Intelligent Manufacturing, School of Bioengineering, Dalian University of Technology, Dalian 116024, China.
² Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China.
³ Yunnan Animal Science and Veterinary Institute, Kunming 650224, China.
⁴ Yunnan Animal Science and Veterinary Institute, Kunming 650224, China. Electronic address: zhaozhiyong988@163.com.
⁵ Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China. Electronic address: caozhenhui@ynau.edu.cn.

PMID: 38145667
DOI: 10.1016/j.scitotenv.2023.169579

Abstract

The study investigated the influence of varied moisture levels in pig manure on the gut microbiome of black soldier fly larvae (BSFL) and their waste conversion efficiency. This encompassed alterations in nutrient components of both BSFL and pig manure, diversity and characterization of the BSFL gut microbiota, and the reciprocal effects between the BSFL gut microbiota and their growth performance and nutrient composition. Additionally, the investigation delved into the changes in the bacterial community and the presence of potential pathogenic bacteria in pig manure. An initial mixture of fresh pig manure and wheat bran was prepared with a 60 % moisture content (Group A). Distilled water was subsequently added to adjust the moisture levels, resulting in mixtures with 65 % (Group B), 70 % (Group C), and 75 % (Group D) moisture content. Each group underwent BSFL digestion over ten days. Groups C (3.87 ± 0.05 mg/worm) and D (3.97 ± 0.08 mg/worm) showed significantly higher bioconversion efficiencies and enhanced BSFL growth compared to Groups A (2.66 ± 0.21 mg/worm) and B (3.09 ± 0.09 mg/worm) (P < 0.05). A 75 % moisture level was identified as ideal, positively influencing fecal conversion efficiency (FCE) (9.57 ± 0.14 %), crude fat intake (8.92 ± 0.56 %), protein (46.60 ± 0.54 %), and total phosphorus (1.37 ± 0.08 %) from pig manure, and subsequent nutrient accumulation in BSFLs. A decline in larval crude ash content indicated higher organic matter and an increased pig manure conversion rate with elevated moisture. High-throughput sequencing and diversity analyses confirmed different moisture contents influenced the BSFL gut microbiota. Bacteroidetes (32.7-62.0 %), Proteobacteria (6.8-29.3 %), Firmicutes (5.8-23.4 %), and Actinobacteria (1.9-29.0 %) were predominant phyla. A 75 % moisture content significantly impacted the BSFL biomass conversion and growth performance. Additionally, Larval feces met non-hazardous fertilizer standards, according to NY-525 (2012).

Keywords: Black soldier fly; Growth performance; Intestinal microorganism; Moisture content; Nutrient component; Pig manure.

MeSH terms

Animals
Bacteria
Diptera*
Feces
Gastrointestinal Microbiome*
Larva
Manure
Swine

Substances

Manure