Effects of β-mannanase supplementation on productive performance, inflammation, energy metabolism, and cecum microbiota composition of laying hens fed with reduced-energy diets

The objective of this study is to investigate the beneficial effects and underlying mechanism of dietary β-mannanase supplementation on the productive performance of laying hens fed with metabolic energy (ME)-reduced diets. A total of 448 Hy-Line gray laying hens were randomly assigned to seven groups. Each group had 8 replicates with 8 hens. The groups included a control diet (CON) with a ME of 2750 kcal/Kg, diets reduced by 100 kcal/Kg or 200 kcal/Kg ME (ME_100 or ME_200), and diets with 0.15 g/Kg or 0.2 g/Kg β-mannanase (ME_100+β-M_0.15, ME_100+β-M_0.2, ME_200+β-M_0.15, and ME_200+β-M_0.2). The productive performance, egg quality, intestinal morphology, inflammatory response, mRNA expression related to the Nuclear factor kappa B (NF-κB) and AMPK pathway, and cecum microbiome were evaluated in this study. ME-reduced diets negatively impacted the productive performance of laying hens. However, supplementation with β-mannanase improved FCR, decreased ADFI, and restored average egg weight to the level of the CON group. ME-reduced diets increased the levels of interleukin-1β (IL-1β) and IL-6 while decreasing the levels of IL-4 and IL-10 in the jejunum of laying hens. However, dietary β-mannanase supplementation improved jejunum morphology, reduced pro-inflammatory cytokine concentrations, and increased levels of anti-inflammatory factors in laying hens fed with ME-reduced diets. The mRNA levels of IL-6, IFN-γ, TLR4, MyD88, and NF-κB in the jejunum of ME-reduced diets were significantly higher than that in CON, dietary β-mannanase supplementation decreased these genes expression in laying hens fed with ME-reduced diets. Moreover, dietary β-mannanase supplementation also decreased the mRNA levels of AMPKα and AMPKγ, and increased the abundance of mTOR in the jejunum of laying hens fed with ME-reduced diets. Cecum microbiota analysis revealed that dietary β-mannanase increased the abundance of various beneficial bacteria (e.g., g_Pseudoflavonifractor, g_Butyricicoccus, and f_Lactobacillaceae) in laying hens fed with ME-reduced diets. In conclusion, dietary β-mannanase supplementation could improve the productive performance of laying hens fed with a ME-reduced diet by improving intestinal morphology, alleviating intestinal inflammation, changing energy metabolism-related signaling pathways, and increasing cecum-beneficial microbiota.

Modulation of Performance, Plasma Constituents, Small Intestinal Morphology, and Cecum Microbiota in Growing Geese by Dietary Citric Acid Supplementation

To investigate the efficiency and optimum inclusion level of CA in growing geese diets on performance, plasma constituents, and intestinal health, 240 healthy female geese at the age of 28d were randomly allotted six treatment diets incorporated with 0, 0.8, 1.6, 2.4, 3.2, and 4% CA. Each treatment group consisted of five replicates and eight birds per replicate. The findings demonstrated that 3.2% CA supplementation resulted in improved growth performance (ADG, ADFI, and FBW) (p = 0.001), and geese who received CA also showed lower body fat contents (p < 0.05) than the control group. Moreover, geese from the 2.4% and 3.2% CA group had the highest plasma glutathione peroxidase and insulin-like growth factor 1 levels compared to the other groups (p < 0.05). A microbial diversity analysis of the cecum conducted by 16S rDNA sequencing revealed that 3.2% CA supplementation showed a significantly higher abundance of beneficial bacteria (Muribaculaceae, CHKCI001, Erysipelotricha-ceae_UCG_003, and UCG_009) (p < 0.05) and a lower abundance of harmful bacteria (Atopobiaceae, Streptococcus, Acinetobacter, Pseudomonas, and Alistipes) (p < 0.10). Collectively, our results revealed that dietary supplementation with 3.2% CA had several benefits on the performance and physiological health of growing geese by promoting nutrients metabolism, improving antioxidant capacity, and modulating cecum microbiota.

Dietary supplementation of solubles from shredded, steam-exploded pine particles modifies gut length and cecum microbiota in cyclic heat-stressed broilers

This study was conducted to investigate the effect of supplementing solubles from steam-exploded pine particles (SSPP) on mitigating the adverse effects of cyclic heat stress (CHS) in broilers which were distributed into 3 dietary treatment groups and 2 temperature conditions. Heat stress (HS) exposure for 6 h daily for 7 d adversely affected performance parameters and rectal temperature of chickens. The absolute and relative weights of the liver and bursa of Fabricius decreased in the CHS group while the relative lengths of the jejunum and ileum increased, which was rescued by dietary supplementation with SSPP. The expression of mucin2 (MUC2) and occludin (OCLN) genes was decreased in CHS birds. The expression of heat shock protein -70 and -90 increased in 0% HS compared to that in 0% NT. Birds supplemented with 0.4% SSPP had higher NADPH oxidase -1 expression than birds in the 0% and 0.1% SSPP treatments. Beta diversity of gut microbiota evaluated through unweighted UniFrac distances was significantly different among treatments. Bacteroidetes was among the 2 most abundant phyla in the cecum, which decreased with 0.1% NT and increased with 0.1% HS in comparison to 0% NT. A total of 13 genera were modified by HS, 5 were altered by dose, and nine showed an interaction effect. In conclusion, CHS adversely affects performance and gut health which can be mitigated with dietary SSPP supplementation that modifies the cecal microbiota in broilers.

Feeding Bacillus subtilis ATCC19659 to Broiler Chickens Enhances Growth Performance and Immune Function by Modulating Intestinal Morphology and Cecum Microbiota

This study investigated dietary supplementation with Bacillus subtilis (BS) ATCC19659 on growth performance, biochemical indices, intestinal morphology, and cecum microflora in broiler chicks. A total of 600 Arbor 1-day Acres broilers of either sex were allotted to 5 treatments: chicks were fed a corn- and soybean-based diet (CON); chicks were fed basal diet containing 500 mg ZnB/kg (ZnB); chicks were fed basal diet containing 1 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-1); chicks were fed basal diet containing 3 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-3); and chicks were fed basal diet containing 5 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-5). Each treatment comprised 6 replicates with 20 birds for each replicate pen. Chicks in the BS-5 and BS-3 groups had higher body weight at the 21^st and 42^nd days and average daily gain from 1 to 21 days than that in the CON group (p < 0.05). Chicks in the BS-5 and ZnB groups had higher serum antioxidant activities and immunity response than those in the CON group (p < 0.05). Compared with the CON group, the liver mRNA abundance of GHR, TGF-β, IGF-1, IFN-γ, SOD, CAT, and GPX of chicks in three BS groups and the ileum villus length (μm) of chicks in BS-3 and ZnB groups was increased (p < 0.05). Compared with the CON group, the villus height-to-crypt depth ratio of the ileum of chicks in the BS-5 and BS-3 groups and the crypt depth and villus height-to-crypt depth ratio of the jejunum in the BS-5 and ZnB groups were increased (p < 0.05). The abundance of the Cyanobacteria phyla in the cecum decreased in response to treatment with both BS-ATCC19659 and ZnB groups (p < 0.05). Compared with the CON group, the cecum abundance of genera GCA-900066575 (Lachnospiraceae), Anaerofustis, and Papillibacter (Firmicutes phylum) in three BS groups were increased (p < 0.05); The abundance of genus Escherichia–Shigella reduced in the BS-3 group (p < 0.05). Compared with the CON group, the cecum abundance of genus Clostridia_unclassified in ZnB and BS-5 groups was decreased (p < 0.05) of broilers. Generally, Bacillus subtilis ATCC19659 as feed additive positively affected growth performance, immunity response, and cecal microflora of broilers.

Dietary Inulin Supplementation Modulates Short-Chain Fatty Acid Levels and Cecum Microbiota Composition and Function in Chickens Infected With Salmonella

The current study investigated the effects of inulin on the gut microbiota, microbiome functions, and short-chain fatty acids (SCFAs) levels in specific pathogen-free (SPF) chickens infected with Salmonella enteritidis (SE). SPF Arbor Acres chickens (n = 240, 1-day-old) were divided into four groups: a control group (CON) fed a basal diet without inulin supplementation or SE infection, and three groups fed a basal diet supplemented with inulin 0, 0.5, and 1% (SE, 0.5%InSE, 1%InSE, respectively) up to 28-days-old, followed by SE challenge at 28 days of age. Cecal SCFA contents and microbiome composition and function were analyzed at 1-day post-infection. The results showed that SE infection significantly decreased cecal butyrate concentrations compared with the CON group (p < 0.05), while inulin supplementation reversed these changes compared with the SE group (p < 0.05). Inulin supplementation at 1% significantly increased the abundances of Lactobacillus and Streptococcus, and significantly decreased the abundances of Subdoligranulum and Sellimonas compared with the SE group (p < 0.05). The functional profiles of microbial communities based on metagenomic sequencing analysis showed that SE infection significantly increased the abundances of pathways related to carbohydrate metabolism, amino acid metabolism, energy metabolism, metabolism of cofactors and vitamins, and glycan biosynthesis and metabolism (p < 0.05), and significantly decreased the abundances of pathways related to nucleotide metabolism, translation, and replication and repair compared with the CON group (p < 0.05), and these effects were reversed by inulin supplementation (0.5 and 1%) (p < 0.05). In conclusion, inulin modulated the dysbiosis induced by SE infection via affecting SCFA metabolism and microbial functional profiles.

Mild heat stress changes the microbiota diversity in the respiratory tract and the cecum of layer-type pullets

The present study aimed to research the effects of cyclic heat environment on the microbial diversity and structure of respiratory tract and cecum of chicken. A total of 360 layer-type pullets at 11 wk of age were subjected to different temperature treatments for 10 wk: constant 22°C; cyclic temperature 22°C to 24°C, 22°C to 26°C, 22°C to 28°C, 22°C to 30°C; the ambient temperature increased from 10:00, reached the set point within 1 h, and maintained until 18:00, thereafter the temperature was restored to 22°C; and the relative humidity was maintained at 60%. The result showed that feed intake of the chickens on ambient temperature 30°C group was significantly lower than that of the chickens on ambient temperature 24°C. The white blood cell, red blood cell, lymphocyte, hemoglobin, and pecked-cell volume content were highest at 24°C on 14, 16, and 18 wk. The ratio of CD3⁺CD4⁺/CD3⁺CD8⁺ T cells was lowest at 30°C. Meanwhile, the abundance of cecum bacteria in chickens at 30°C was lower than that at 24°C. Cyclic heat environment temperature treatment did not significantly affect the concentration of secretory immunoglobulin A in chicken bronchoalveolar lavage fluid (BALF) levels during 10 wk of trial. The diversity index analysis showed that the effect of 24°C on the cecum flora of chickens was optimal. Abundance of Firmicutes bacteria in the lung flora and cecum flora was lower at 30°C than at 24°C group. Similarly, the microorganism, Brevibacillus in the BALF was also significantly lower at 24°C. In conclusion, cyclic 24°C treatment was beneficial for the feed intake, blood routine indexes, microflora structure of the cecum, and respiratory tract in laying pullets.

Comparison of Bacterial Populations in the Ceca of Swine at Two Different Stages and their Functional Annotations

The microbial composition in the cecum of pig influences host health, immunity, nutrient digestion, and feeding requirements significantly. Advancements in metagenome sequencing technologies such as 16S rRNAs have made it possible to explore cecum microbial population. In this study, we performed a comparative analysis of cecum microbiota of crossbred Korean native pigs at two different growth stages (stage L = 10 weeks, and stage LD = 26 weeks) using 16S rRNA sequencing technology. Our results revealed remarkable differences in microbial composition, α and β diversity, and differential abundance between the two stages. Phylum composition analysis with respect to SILVA132 database showed Firmicutes to be present at 51.87% and 48.76% in stages L and LD, respectively. Similarly, Bacteroidetes were present at 37.28% and 45.98% in L and LD, respectively. The genera Prevotella, Anaerovibrio, Succinivibrio, Megasphaera were differentially enriched in stage L, whereas Clostridium, Terrisporobacter, Rikenellaceae were enriched in stage LD. Functional annotation of microbiome by level-three KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis revealed that glycine, serine, threonine, valine, leucine, isoleucine arginine, proline, and tryptophan metabolism were differentially enriched in stage L, whereas alanine, aspartate, glutamate, cysteine, methionine, phenylalanine, tyrosine, and tryptophan biosynthesis metabolism were differentially enriched in stage LD. Through machine-learning approaches such as LEfSe (linear discriminant analysis effect size), random forest, and Pearson's correlation, we found pathways such as amino acid metabolism, transport systems, and genetic regulation of metabolism are commonly enriched in both stages. Our findings suggest that the bacterial compositions in cecum content of pigs are heavily involved in their nutrient digestion process. This study may help to meet the demand of human food and can play significant roles in medicinal application.