Trypoxylus dichotomus Gut Bacteria Provides an Effective System for Bamboo Lignocellulose Degradation

Effects of fermented bamboo fiber on intestinal health and fecal pollutants in weaned piglets

Introduction

Weaning stress adversely affects piglet growth and development, thereby reducing the economic efficiency of pig farming operations. Furthermore, pig feces are a major source of environmental pollution, underscoring the need for effective strategies to mitigate fecal output at its source.

Methods

This study investigated the effects of dietary supplementation with fermented bamboo fiber (FBF) on growth performance, intestinal barrier integrity, gut microbiota composition, and fecal pollutant levels in weaned piglets. A total of 144 Duroc × Landrace × Yorkshire piglets, weaned at 21 days of age, were randomly assigned to 4 groups, with six replicates per group and 6 piglets per replicate. The control group (CON) received a basal diet, while the three treatment groups were fed the basal diet supplemented with 1, 1.5, and 2% FBF, respectively. The trial lasted 30 days.

Results

The findings revealed that FBF supplementation fortified the intestinal barrier, modulated colonic microbial communities, and decreased fecal pollutant levels. Among the treatment groups, supplementation with 1.5% FBF produced the most significant improvements in piglets' growth performance and intestinal barrier function, as well as the strongest microbial interactions and the greatest reduction in fecal pollutants.

Discussion

These results suggest that FBF supplementation can alleviate weaning stress and mitigate the environmental impact of pig feces, with 1.5% identified as the optimal supplementation level.

Turning trash into treasure: Hermetia illucens microbiome and biodegradation of industrial side streams

Black soldier fly larvae (BSFL) have attracted attention due to their ability to upcycle various biological side streams into valuable biomass, such as proteins, lipids, and chitin. In this study, we investigated the impact of high-fiber diets on larval growth performance and the shift of microbes in the gut. We tested empty fruit bunches (EFB), potato pulp (PP), and cottonseed press cake (CPC), with chicken feed (CF) used as a control diet. We found that larvae reared on the EFB, PP, and CPC were smaller than control larvae at the end of development due to the low nutritional value of the diets. However, survival rates of more than 90% were observed regardless of the diet. We used a cultivation-dependent approach to analyze the microbial community in the gut of BSFL, isolated, and identified a total of 329 bacterial strains. Bacillaceae were most frequently isolated from larvae reared on the high-fiber EFB diet. These isolates were predicted to degrade cellulose in silico and this was subsequently confirmed in vitro using the Congo Red assay. Whereas the members of Enterobacteriaceae and Morganellaceae were mostly found in guts of larvae reared on the high-protein diets CPC and CF. We conclude that the gut microbiome plays a crucial role in the digestion of fiber-rich plant organic material, thereby enabling the BSFL to successfully complete their life cycle also on substrates with low nutritional value. As a result, BSFL convert industrial side streams into valuable biomass, reducing waste and promoting sustainability.

IMPORTANCE

Organic side streams from various industries pose a challenge to the environment. They are often present in huge amounts and are mostly discarded, incinerated, used for biogas production, or as feed for ruminant animals. Many plant-based side streams contain difficult-to-digest fiber as well as anti-nutritional or even insecticidal compounds that could harm the animals. These challenges can be addressed using black soldier fly larvae, which are known to degrade various organic substrates and convert them into valuable biomass. This will help mitigate agro-industrial side streams via efficient waste management and will contribute to the more economical and sustainable farming of insects.

Elucidating the structure, and composition of bacterial symbionts in the gut regions of wood-feeding termite, Coptotermes formosanus and their functional profile towards lignocellulolytic systems

The wood-feeding termite, Coptotermes formosanus, presents an efficient lignocellulolytic system, offering a distinctive model for the exploration of host-microbial symbiosis towards lignocellulose degradation. Despite decades of investigation, understanding the diversity, community structure, and functional profiles of bacterial symbionts within specific gut regions, particularly the foregut and midgut of C. formosanus, remains largely elusive. In light of this knowledge gap, our efforts focused on elucidating the diversity, community composition and functions of symbiotic bacteria inhabiting the foregut, midgut, and hindgut of C. formosanus via metagenomics. The termite harbored a diverse community of bacterial symbionts encompassing 352 genera and 26 known phyla, exhibiting an uneven distribution across gut regions. Notably, the hindgut displayed a higher relative abundance of phyla such as Bacteroidetes (56.9%) and Spirochetes (23.3%). In contrast, the foregut and midgut were predominantly occupied by Proteobacteria (28.9%) and Firmicutes (21.2%) after Bacteroidetes. The foregut harbored unique phyla like Candidate phylum_TM6 and Armatimonadetes. At the family level, Porphyromonadaceae (28.1, 40.6, and 53.5% abundance in foregut, midgut, and hindgut, respectively) and Spirochaetaceae (foregut = 9%, midgut = 16%, hindgut = 21.6%) emerged as dominant families in the termite's gut regions. Enriched operational taxonomic units (OTUs) were most abundant in the foregut (28), followed by the hindgut (14), while the midgut exhibited enrichment of only two OTUs. Furthermore, the functional analyses revealed distinct influences of bacterial symbionts on various metabolic pathways, particularly carbohydrate and energy metabolisms of the host. Overall, these results underscore significant variations in the structure of the bacterial community among different gut regions of C. formosanus, suggesting unique functional roles of specific bacteria, thereby inspiring further investigations to resolve the crosstalk between host and microbiomes in individual gut-regions of the termite.

Fermented Bamboo Fiber Improves Productive Performance by Regulating Gut Microbiota and Inhibiting Chronic Inflammation of Sows and Piglets during Late Gestation and Lactation

Sows exhibit metabolic syndrome and significant changes in intestinal microbiota during late gestation and lactation, affecting sow performance and piglet health. Dietary fiber (DF) is widely applied to improve sow performance by modulating gut microbiota and their by-products. Here, 60 sows were randomly allocated to groups, including CON (8% wheat bran), FBF-1 (1% fermented bamboo fiber), FBF-2 (2.5% fermented bamboo fiber), and FBF-3 (4% fermented bamboo fiber) from day 80 of gestation (G80d) to the end of lactation (L21d). Compared with CON, the FBF-3 diet decreased lactation backfat loss, increased average daily feed intake (ADFI) during lactation, and the weight gain of piglets, while supplementation of FBF increased fecal water content and reduced the rate of constipation in sows. Further, the yield and quality of milk of sows in FBF groups were improved. The FBF-3 diet significantly reduced markers of intestinal permeability (diamine oxidase and endotoxin) and systemic inflammation (interleukin-6 [IL-6] and tumor necrosis factor alpha) in sow serum during lactation, while it increased the anti-inflammatory marker (IL-10). Similarly, the piglets in the FBF-2 and FBF-3 groups had lower levels of IL-6 and higher levels of IgG, IgM, and insulin-like growth factor in serum. In addition, sows fed the 4% FBF diet had higher levels of acetate, propionate, butyrate, and total short-chain fatty acids (SCFAs) in feces than CON, and total SCFAs were promoted in piglets from the FBF-3 group. Spearman correlation analysis showed that immunity, inflammation, and intestinal microbiota are closely related to sow performance, which can affect piglet growth. The potential mechanism could be that FBF promoted the enrichment of beneficial genera such as Lachnospira, Lachnospiracea_XPB1014_Group, and Roseburia and the production of SCFAs in the sow's intestine, and reduced the relative abundance of harmful bacteria such as Fusobacterium, Sutterellaceae, and Sutterella. Meanwhile, the intake of FBF by sows affected the gut microbial composition of their offspring piglets, significantly increasing the relative abundance of beneficial bacteria Alistipes and Lachnoclostridium and decreasing the relative abundance of pathogenic bacteria Trueperella among colonic microorganisms. IMPORTANCE Dietary fiber is widely applied in the nutrition of sows due to its potential value in improving performance and intestinal health. Fermented bamboo fiber, rich in dietary fiber, has not been fully evaluated to be used in sow diets. Sows mobilize body reserves during gestation and lactation due to nutrients being prioritized for lactation purposes while feeding piglets, which generally leads to metabolism and immunity undergoing drastic changes. The main manifestations are increased inflammation and intestinal permeability and disturbed intestinal flora, which ultimately reduces the ADFI and milk quality, thus affecting the growth of piglets. The study described here is the first attempt to provide FBF for sows in late gestation and lactation can reverse this process. The 4% FBF was initially explored to have the most significantly beneficial effect. It provides a potentially effective method for dietary modification to control the gut microbiota and its metabolites to improve sow and piglet health. Moreover, the sow-piglet model offers a reference for investigating the impact of dietary fiber on the intestinal health of human mothers and infants.

CAZyme from gut microbiome for efficient lignocellulose degradation and biofuel production

Over-exploitation and energy security concerns of the diminishing fossil fuels is a challenge to the present global economy. Further, the negative impact of greenhouse gases released using conventional fuels has led to the need for searching for alternative biofuel sources with biomass in the form of lignocellulose coming up as among the potent candidates. The entrapped carbon source of the lignocellulose has multiple applications other than biofuel generation under the biorefinery approach. However, the major bottleneck in using lignocellulose for biofuel production is its recalcitrant nature. Carbohydrate Active Enzymes (CAZymes) are enzymes that are employed for the disintegration and consumption of lignocellulose biomass as the carbon source for the production of biofuels and bio-derivatives. However, the cost of enzyme production and their stability and catalytic efficiency under stressed conditions is a concern that hinders large-scale biofuel production and utilization. Search for novel CAZymes with superior activity and stability under industrial condition has become a major research focus in this area considering the fact that the most conventional CAZymes has low commercial viability. The gut of plant-eating herbivores and other organisms is a potential source of CAZyme with high efficiency. The review explores the potential of the gut microbiome of various organisms in the production of an efficient CAZyme system and the challenges in using the biofuels produced through this approach as an alternative to conventional biofuels.