Effects of Rhodotorula mucilaginosa fermentation product on the laying performance, egg quality, jejunal mucosal morphology and intestinal microbiota of hens

Comparative Study of the Productive Parameters of Two Breeds of the Bombyx mori Silkworm Fed Rhodotorula glutinis Yeast

In this study, a comparative approach was used with the aim of filling the knowledge gap regarding the productive and economic parameters of two native B. mori silkworm breeds (Lines C and Z) fed with different diets, namely mulberry leaves alone and mulberry leaves with R. glutinis yeast at two different concentrations (1 × 109 and 1 × 107 CFU/mL). The trifactorial experiment was carried out with 600 silkworms during the fifth instar, with 300 for each breed and 50 larvae per rearing tray. The larvae were randomly assigned into three feeding groups, with two replicates: in the control group (C), the larvae received ordinary mulberry leaves; in the first experimental group (RG-1), the larvae were given mulberry leaves supplemented with R. glutinis yeast at a 1 × 107 concentration; and in the second experimental group (RG-2), the larvae received the same quantity of mulberry leaves as the C and RG-1 groups, but with R. glutinis yeast at a 1 × 109 concentration. Line C larvae in the RG-1 group revealed higher values for most of the productive traits assessed. There was a positive and significant correlation between the weights and lengths of the larvae and the silk gland, the silk gland and the shell, the cocoon and the pupae and the shell, and the shell and the pupa size (p < 0.001). The steady decline in the parameters at a higher concentration suggests that R. glutinis positively influences a number of silkworm growth features at a recommended dosage of 1 × 107; however, further research is required to more precisely identify the mechanisms involved.

Rhodotorula Yeast Culture Improved the Antioxidant Capacity, Lipid Metabolism, and Immunity of Sheep Livers

There is currently no research on the application evaluation of R. mucilaginosa yeast culture (RYC) in animal production. Therefore, this study investigated the effects of RYC on the antioxidant capacity, lipid metabolism, and immunity of sheep livers. Twenty-four 3-month-old Duhan male sheep (36 ± 4 kg) were divided into four groups. The control group received a basal diet, the L group received a basal diet + 10 g/sheep/day RYC, the M group received a basal diet + 20 g/sheep/day RYC, and the H group received a basal diet + 40 g/sheep/day RYC. The trial lasted for 75 days. The results showed that the content of glutathione peroxidase in the livers of sheep in group M was significantly increased by 26.6%, and the content of malondialdehyde was significantly decreased by 38% (p < 0.05). Additionally, the serum levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol significantly decreased; the liver content of C16:0 decreased; and the levels of C18:2n6C and C20:1 increased (p < 0.05). Furthermore, the contents of cytokines TNF-α and IFN-γ in sheep livers from the M group were also significantly decreased by 20% and 24.8%, respectively (p < 0.05). These findings suggest that supplementation with 20 g/sheep/day RYC can enhance antioxidant capacity, improve lipid metabolism, and reduce inflammation in sheep livers, which is advantageous for farming healthy sheep.

The Effects of Unconventional Feed Fermentation on Intestinal Oxidative Stress in Animals

Unconventional feed, which is abundant in China, contains anti-nutritional factors and toxins; however, these can be greatly reduced with microbial fermentation, thus improving the nutrient content of the feed, enhancing animal appetites, and ultimately significantly improving the intestinal health and growth performance of animals. When oxidative stress occurs, fermented feed can effectively reduce the damage caused by stress to the gastrointestinal tract, accelerate the removal of gastrointestinal abnormalities, improve the ability to resist intestinal stress, and ensure the efficient production of animals. This review introduces the application of unconventional fermented feed in animal production, and expounds upon the function of unconventional fermented feed in animals with oxidative stress symptoms, so as to provide a theoretical reference for the development and application of unconventional fermented feed in antioxidative stress reduction.

Rhodotorula mucilaginosa ZTHY2 Attenuates Cyclophosphamide-Induced Immunosuppression in Mice

Rhodotorula mucilaginosa (R. mucilaginosa) can enhance the immune and antioxidant function of the body. However, whether R. mucilaginosa has an immunoregulatory effect on cyclophosphamide (CTX)-induced immunosuppressed animals remains to be clarified. In this study, the R. mucilaginosa ZTHY2 that we isolated from the coastal waters of the South China Sea previously was prepared in order to investigate its immunoprotective effect on CTX-induced immunosuppression in mice, and the effects were compared to those of Lactobacillus acidophilus (LA) (a well-known probiotic). Seventy-two male SPF mice were divided into six groups: The C group (control); IM group (immunosuppressive model group) (+CTX); Rl, Rm, and Rh groups (+CTX+low, medium, and high concentration of R. mucilaginosa, respectively); and PC (positive control) group (+CTX+LA). After a 28-day feeding trial, blood samples were taken for biochemical and serum immunological analysis, and the thymus and spleen were collected to analyze the organ index, lymphocyte proliferation and differentiation, and antioxidant capacity. The findings showed that R. mucilaginosa ZTHY2 improved the spleen and thymus indices, effectively attenuated immune organ atrophy caused by CTX, and enhanced the proliferation of T and B lymphocytes induced by ConA and LPS. R. mucilaginosa ZTHY2 promoted the secretion of cytokines and immunoglobulins and significantly increased the contents of IL-2, IL-4, IL-6, TNF-α, IFN-γ, IgA, IgG, IgM, CD4, CD8, CD19, and CD20 in serum. The proportion of CD4+, CD8+, CD19+, and CD20+ lymphocytes in spleen, thymus, and mesenteric lymph nodes were increased. In addition, R. mucilaginosa ZTHY2 reduced the reactive oxygen species (ROS) and malondialdehyde (MDA) levels and increased glutathione (GSH), total superoxide dismutase (SOD), and catalase (CAT) levels. Our results indicated that R. mucilaginosa ZTHY2 can significantly enhance the immune function of immunosuppressed mice, and improving antioxidant capacity thus attenuates CTX-induced immunosuppression and immune organ atrophy.

Mitigation of heat stress effects on laying hens' performances, egg quality, and some blood parameters by adding dietary zinc-enriched yeasts, parsley, and their combination

Objective

Finding natural, handy and efficient nutritional solutions to prevent and mitigate negative effects caused by environmental heat stress and to be applied to large-scale laying hen industry.

Research design

A 3-weeks trial was conducted on 128 laying hens TETRA-SL LL (50 weeks of age) housed in 8 cages/group, 4 laying hens/cage, 32 laying hens/group, under heat stress conditions (34±1°C). The basal diet on corn and soybean meal was formulated to be isocaloric and isonitrogenic. Compared to Control group diet (C), experimental groups E1 included 1% zinc-enriched yeast; E2 included 2% parsley and E3 included 1% zinc-enriched yeast combined with 2% parsley to minimize the heat stress effects.

Methods

The parsley and the zinc-enriched yeast were analysed for their chemical composition, total polyphenols, antioxidant capacity, minerals, vitamin E and incorporated into the ration structure. Production parameters, egg quality, biochemical and haematological profiles of blood samples were analysed during the trial.

Results

A statistically significant (p < 0.05) average egg weight was noticed on E2 and E3 compared to Control group, and also during the 1st week compared to the 2nd and the 3rd experimental weeks. Average daily feed intake values were highly significant (p < 0.001) on E3 group compared to C, E1, E2, and on the 2nd week compared to the 3rd experimental week (p < 0.021). Feed conversion rate was highly significant (p < 0.001) during the 2nd and the 3rd experimental weeks compared to the 1st week. The average daily egg production was highly significant (p < 0.001) within 1st week compared to the 2nd and 3rd weeks. A highly significant (p < 0.001) yolk coloration was noticed on E2 and E3 groups. The malondialdehyde (MDA) concentration decreased significantly (p < 0.05) to all experimental groups compared to Control group during the 14th and 28th days of storage.

Conclusion

These findings suggest that the two ingredients minimized the heat stress effects on production performance parameters with a demonstrated antioxidant capacity role by delaying the lipid peroxidation during different storage time periods.

Low Ca diet leads to increased Ca retention by changing the gut flora and ileal pH value in laying hens

Osteoporosis is a common degenerative metabolic bone disease in caged laying hens. Intensive egg production mobilizing large amounts of Ca from bone for eggshell formation, consequently leading to Ca deficiency, has been recognized as a critical factor causing osteoporosis in commercial laying hens. The aim of this study was to examine the effect of Ca deficiency on the function of the gut microbiota-bone axis and related egg production traits and bone health in laying hens. Twenty-four 48-week-old laying hens were fed a control diet (Control, 3.72%) or a low Ca diet (LC, 2.04%) for 60 d (n = 12). Compared to the Control hens, the LC hens had higher levels of alkaline phosphatase and tartrate resistant acid phosphatase (P < 0.05) with lower bone strength, eggshell thickness, and eggshell strength (P < 0.05). In addition, the LC hens had higher plasma estradiol concentrations, while having lower concentrations of interleukin-1 (IL-1) and IL-6. The LC hens also had a lower pH value in the ileum with an increased Ca retention. The principal co-ordinates analysis showed significantly separate cecal microbiota populations between the Control and LC hens. The Prevotellaceae_UCG-001, Subdoligranulum, Peptococcus, and Eubacterium_hallii_group (P < 0.05) were higher, while the CHKC1001 and Sutterella (P < 0.05) were lower at the genus level in the LC hens. In addition, Prevotellaceae_UCG-001, Subdoligranulum and Eubacterium_hallii_group had a negative correlation, while Sutterella was positively correlated with ileal pH values. The transcriptome analysis revealed that the low Ca diet caused 20 and 31 genes to be significantly up- and down-regulated, respectively. The gene expressions of cystic fibrosis transmembrane conductance regulator, solute carrier family 26 member 3 of the anion exchangers, and mitogen-activated protein kinase 12 of pro-inflammatory factors were lower in the LC birds, which was correlated with the lower ileal pH values. These results suggest that the hens with low Ca diet-induced osteoporosis have an increased intestinal Ca retention with a decreased ileal pH value, correlated with the changes in Prevotellaceae_UCG-001, Subdoligranulum, and Eubacterium_hallii_group of beneficial genera. The results provide insights for further understanding and preventing osteoporosis in laying hens.

Dietary replacement of soybean meal by fermented feedstuffs for aged laying hens: effects on laying performance, egg quality, nutrient digestibility, intestinal health, follicle development, and biological parameters in a long-term feeding period

This study aimed to investigate the effects of dietary supplementation with fermented soybean meal (FSM) or fermented miscellaneous meal (FMM, cottonseed meal: coconut meal = at a 1:1 ratio) on the intestinal health, laying performance, egg quality, and follicle development of laying hens. A total of 1,008 54-wk-old laying hens were randomly divided into 7 treatment groups and fed a corn-soybean base diet in addition to 2%, 4%, and 8% FSM or FMM. The results showed that fermentation increased the contents of crude protein, amino acids (Ser, Gly, Cys, Leu, Lys, His, and Arg), and organic acids (butyric acid, citric acid, succinic acid) and decreased the contents of neutral and acid detergent fiber in the soybean and miscellaneous meals (P < 0.05). Compared with the results found for the control group, feeding with 4% FSM increased the egg production, egg mass and average daily feed intake (ADFI), and feeding with 4% FMM increased the ADFI of laying hens (P < 0.05). Furthermore, feeding with 8% FMM reduced the productive performance and laying performance, supplementation with 4% FSM increased the eggshell strength and weight, and 2 to 4% FSM increased the egg albumen height and Haugh unit (P < 0.05). Moreover, 2 to 8% FSM or 2 to 4% FMM enhanced the apparent digestibility of dry matter, crude protein, and NDF for laying hens (P < 0.05). The relative weight, villus height, crypt depth, and villus:crypt ratio of the jejunum were higher in the 4% FSM- and FMM-fed groups (P < 0.05). Moreover, diamine oxidase (DAO) activity, transepithelial electrical resistance (TEER), and the expression of tight junction proteins (ZO-1, Occluding, and Claudin1), the intestinal stem cell marker Lgr5, and the proliferation cell marker proliferating cell nuclear antigen (PCNA) was upregulated in the jejunum of laying hens fed 4% FSM and FMM (P < 0.05). The relative weight of the ovaries, and the number of small yellow follicles and large white follicles were elevated after 4% FSM or FMM supplementation. Furthermore, the levels of serum follicle-stimulating hormone and luteinizing hormone were increased in the 4% FSM and FMM groups (P < 0.05). In conclusion, the supplementation of laying hen feed with FSM and FMM improved the laying performance, egg quality, intestinal barrier function, and follicle development of aged laying hens, and 4% FSM supplementation was optimal.

Study on the fermentation effect of Rhodotorula glutinis utilizing tofu whey wastewater and the influence of Rhodotorula glutinis on laying hens

Background

Tofu whey wastewater (TWW) is the wastewater of tofu processing, which is rich in a variety of nutrients. Rhodotorula glutinis can make full use of TWW to ferment and reproduce yeast cells, produce carotenoids and other nutrients, improve the utilization value of TWW, and reduce environmental pollution and resource waste.

Methods

In this study, the nutrient composition changes of TWW treated by Rhodotorula glutinis were analyzed to reformulate TWW medium, and the optimal composition and proportion of TWW medium that can improve the biomass and carotenoids production of Rhodotorula glutinis were explored. Meanwhile, the Rhodotorula glutinis liquid obtained under these conditions was used to prepare biological feed for laying hens, and the effect of Rhodotorula glutinis growing on TWW as substrate on laying performance and egg quality of laying hens were verified.

Results

The results showed that the zinc content of TWW after Rhodotorula glutinis fermentation increased by 62.30%, the phosphorus content decreased by 42.31%, and the contents of vitamin B1, B2 and B6 increased to varying degrees. The optimal fermentation conditions of Rhodotorula glutinis in the TWW medium were as follow: the initial pH was 6.40, the amount of soybean oil, glucose and zinc ions was 0.80 ml/L, 16.32 g/L, and 20.52 mg/L, respectively. Under this condition, the biomass of Rhodotorula glutinis reached 2.23 g/L, the carotenoids production was 832.86 μg/g, and the number of effective viable yeast count was 7.08 × 10⁷ cfu/ml. In addition, the laying performance and egg quality of laying hens fed Rhodotorula glutinis biological feed were improved.

Discussion

In this study, we analyzed the composition changes of TWW, optimized the fermentation conditions of Rhodotorula glutinis in TWW medium, explored the influence of Rhodotorula glutinis utilizing TWW on laying layers, and provided a new idea for the efficient utilization of TWW.

Rhodotorula benthica culture as an alternative to antibiotics improves growth performance by improving nutrients digestibility and intestinal morphology, and modulating gut microbiota of weaned piglets

The effects of Rhodotorula benthica culture (RBC) and antibiotics (AB) on the growth performance, nutrients digestibility, morphological indicators, and colonic microbiota of weaning piglets were explored. Ninety-six (Duroc × Landrace × Large) weaned piglets (21-day-old) weighing 7.7 ± 0.83 kg, were randomly allocated to 4 dietary treatments. They were fed with basal diet (CON), basal diet + 25 mg/kg bacitracin zinc + 5 mg/kg colistin sulfate (AB), 5 g/kg reduction in soybean meal of basal diet + 5 g/kg RBC (RBC1), or 10 g/kg reduction in soybean meal of basal diet + 10 g/kg RBC (RBC2). The results showed that dietary RBC1 improved the body gain/feed intake (G/F) of weaned piglets than the CON diet, and the RBC2 diet improved the average daily gain and G/F than CON and AB diets from days 15 to 28 (P < 0.05). Supplementation of RBC2 improved the apparent total tract digestibility of dry matter, nitrogen, and gross energy in weaned piglets compared to controls from days 15 to 28 (P < 0.05). Dietary AB, RBC1, and RBC2 enhanced the ileal villus height (VH) and VH/crypt depth (CD), and these two indicators were greater in the RBC2-treated piglets than in the AB- and RBC1-treated piglets (P < 0.05). The activity of serum superoxide dismutase (SOD) was enhanced by dietary AB, RBC1, and RBC2 (P < 0.05). Serum glutathione (GSH) concentration was elevated by dietary RBC1 and RBC2 (P < 0.05). According to 16S rRNA sequence analysis, AB- and RBC2-treated piglets had a higher relative abundance of Firmicutes and Lachnospiraceae in the colon digesta, and more abundant Lactobacillus was found in RBC1-treated piglets, as compared to the CON group. Additionally, RBC2 supplementation increased the α diversity [Chao1, PD-whole-tree, and observed operational taxonomic units (OTUs)] compared to the CON group. Taken together, the dietary RBC improved the growth performance of weaned piglets. In addition, 10 g/kg of RBC2 in the diet achieved better effects on higher ADG, ileal villi morphology, and stronger antioxidant capacity than dietary AB and RBC1 in weaning piglets.

Effects of Dietary Fucoidan Supplementation on Serum Biochemical Parameters, Small Intestinal Barrier Function, and Cecal Microbiota of Weaned Goat Kids

The purpose of this study was to evaluate the effects of fucoidan supplementation on serum biochemical parameters, small intestinal barrier function, and cecal microbiota of weaned goat kids. A total of 60 2-month-old weaned castrated male goat kids (Chuanzhong black goat) were used in this 30-day experiment. The goat kids were randomly divided into four groups: a control group (CON) fed the basal diet, and three other groups supplemented with 0.1%, 0.3%, and 0.5% fucoidan in the basal diet (denoted as F1, F2, and F3 groups, respectively). The results indicated that dietary fucoidan supplementation decreased (p < 0.05) the activity of lactate dehydrogenase (LDH) and the content of glucose (GLU) as measured on day 15. As measured on day 30, dietary fucoidan increased (p < 0.05) the content of total protein (TP) and decreased the activity of aspartate aminotransferase (AST), and supplementation with 0.3% and 0.5% fucoidan decreased (p < 0.05) the activity of LDH. Dietary fucoidan decreased (p < 0.05) the content of D-lactic acid (D-LA) and the activity of diamine oxidase (DAO). Dietary fucoidan increased (p < 0.05) the activity of catalase (CAT) in the duodenum. Dietary 0.3% and 0.5% fucoidan enhanced (p < 0.05) the activity of glutathione peroxidase (GSH-Px) in the ileum, the activity of total superoxide dismutase (T-SOD) in the jejunum and ileum, and the activity of CAT in the ileum. Dietary 0.3% and 0.5% fucoidan reduced the contents of malondialdehyde (MDA) in the duodenum, jejunum, and ileum and the content of hydrogen peroxide (H2O2) in the duodenum. Dietary fucoidan increased (p < 0.05) the content of secretory immunoglobulin A (sIgA) in the duodenum. Supplementation of 0.3% and 0.5% fucoidan upregulated (p < 0.05) the gene expression of ZO-1 and claudin-1 in the duodenum, jejunum, and ileum, and dietary supplementation of 0.3% and 0.5% fucoidan upregulated (p < 0.05) the gene expression of occludin in the jejunum and ileum. The 16S rRNA high-throughput sequencing results showed that at the phylum level, dietary fucoidan increased (p < 0.05) the abundance of Bacteroidetes while decreasing (p < 0.05) the abundance of Firmicutes. At the genus level, dietary 0.3% and 0.5% fucoidan increased (p < 0.05) the abundances of Unspecified_Ruminococcaceae, Unspecified_Bacteroidale, Unspecified_Clostridiales, and Akkermansia. In conclusion, dietary fucoidan supplementation had positive effects on intestinal permeability, antioxidant capacity, immunity function, tight junctions, and the cecal microflora balance in weaned goat kids.

Effects of Rhodotorula mucilaginosa on the Immune Function and Gut Microbiota of Mice

As a dominant species among marine yeasts, Rhodotorula benthica accounts for ~50% of all marine yeasts. Rhodotorula is rich in a variety of bioactive substances and commonly used in the production of carotenoids by microbial fermentation and is worth developing. Therefore, the present study used a strain of Rhodotorula mucilaginosa isolated from the coastal waters of the South China Sea as the target yeast to investigate its impact on the immune function and gut microbiota of mice. A total of 200 mice were randomly divided into gavage groups and control group and garaged for 30 consecutive days at different concentration. Samples were collected on day 15 and day 30 of gavage administration. The results showed that R. mucilaginosa ZTHY2 could increase the thymus and spleen indices of mice, and its effect on the thymus index was more significant after long-term gavage administration. Short-term (15 days) gavage administration of R. mucilaginosa suspension enhanced delayed hypersensitivity in mice, increased serum IgG, IgA, and IL-2. Long-term (30 days) gavage administration of R. mucilaginosa suspension significantly enhanced the phagocytosis of macrophages in mice and significantly increased serum TNF-α and INF-γ. R. mucilaginosa ZTHY2 altered the structure of the gut microbiota of mice at the phylum and genus levels, leading to an increased relative abundance of Firmicutes and Lactobacillus and a decreased relative abundance of Bacteroidetes. This strain increased the beneficial intestinal bacteria and reduced the harmful intestinal bacteria in mice. This study provides experimental evidence and lays the foundation for the future development and application of this strain as a microecological source of carotenoids.

Active Yeast but Not Henhouse Environment Affects Dropping Moisture Levels in Egg-Laying Hens

Simple Summary

The high dropping moisture content of chicken feces can impose a serious burden on poultry production costs and the environment. In the first part of this study, we investigated the correlations among chicken dropping moisture content, environmental factors, and production performance. In the second part, we explored whether the addition of three types of additives added individually could reduce the dropping moisture content. The results showed that the dropping moisture level was not associated with production performance or any environmental factors at different locations at the same henhouse height. The probiotic additive (active yeast) significantly reduced the dropping moisture rate. These findings can improve strategies for dealing with high dropping moisture levels and contribute to the enhancement of chicken production.

Abstract

Dropping moisture (DM) refers to the water content in feces. High DM negatively affects poultry production, environment, production costs, and animal health. Heredity, nutrition, environment, and disease may affect DM level. DM has medium inheritability and is related to cage height in henhouses. We examined the relationship among DM level, production performance, and environmental factors at different locations at the same henhouse height and effects of three types of additives. We measured the correlation between environmental factors including temperature, humidity, CO₂ concentration, absolute pressure, and DM levels and laying performance of 934 Rhode Island Red hens. DM level was not significantly associated with environmental factors or production performance. We divided 64 persistently high DM hens into control and treatment groups supplied with different additives (probiotics, anisodamine, and antibiotics). DM levels, laying performance, egg quality, and serum biochemical indices were determined. Compared with the control and antibiotics, probiotics significantly reduced DM levels and eggshell strength while improving yolk color but did not significantly affect production performance. The additives reduced the b value of eggshell color; compared with probiotics, anisodamine decreased serum globulin levels. Exogenous active yeast supplementation can significantly reduce DM levels.

Antarctic Strain of Rhodotorula mucilaginosa UFMGCB 18,377 Attenuates Mucositis Induced by 5-Fluorouracil in Mice

Mucositis is one of the most strenuous side effects caused by chemotherapy drugs, such as 5-fluorouracil (5-FU), during the treatment of several types of cancers. The disease is so prevalent and aggressive that many patients cannot resist such symptoms. However, despite its frequency and clinical significance, there is no effective treatment to prevent or treat mucositis. Thus, the use of probiotics as an adjuvant for the treatment has gained prominence. In the present study, we evaluated the effectiveness of oral administration of the Antarctic strain of Rhodotorula mucilaginosa UFMGCB 18,377 as an alternative to minimize side effects of 5-FU-induced mucositis in mice. Body weight, food consumption, stool consistency, and presence of blood in the feces were assessed daily in mice orally treated or not with the yeast and submitted or not to experimental mucositis. Blood, bones, and intestinal tissues and fluid were used to determine intestinal permeability and immunological, microbiological, and histopathological parameters. Treatment with R. mucilaginosa UFMGCB 18,377 was able to decrease clinical signs of the disease, such as reduction of food intake and body weight loss, and also decreased the number of intestinal enterobacteria and intestinal length shortening. Additionally, treatment was able to decrease the levels of MPO and EPO activities and inflammatory infiltrates, as well as the histopathological lesions characteristic of mucositis in the jejunum and ileum. Results of the present study showed that the oral administration of R. mucilaginosa UFMGCB 18,377 protected mice against mucositis induced by 5-FU.

In Vitro and In Vivo Evaluation of the Probiotic Potential of Antarctic Yeasts

Antarctica is one of the most pristine and inhospitable regions of the planet, mostly inhabited by microorganisms that survive due to unusual metabolic pathways to adapt to its extreme conditions, which could be interesting for the selection of new probiotics. The aim of the present study was to screen in vitro and in vivo putative probiotics among 254 yeasts isolated from different habitats of Antarctica. In vitro selection evaluated functional (growth at 37 °C, resistance to simulated gastric environment, and to bile salts), safety (degradation of mucin, production of β-haemolysis and resistance to antifungal drugs), and beneficial (production of antagonistic substances and adhesion to pathogens) properties. Twelve yeasts were able to grow at 37 °C, one of which was eliminated to present β-haemolytic ability. The remained yeasts resisted to gastric simulation and bile salts, but none presented antagonism against the pathogens tested. Because of the high co-aggregation with Salmonella enterica Typhimurium and growth yield, Rhodotorula mucilaginosa UFMGCB 18377 and Saccharomyces cerevisiae UFMGCB 11120 were selected for in vivo steps using mice challenged with S. Typhimurium. Both yeasts reached high faecal population levels when daily administered, but only R. mucilaginosa UFMGCB 18377 protected mice against Salmonella infection presenting a higher survival and reduced weight loss, bacterial translocation to the liver, sIgA intestinal levels, and intestinal and hepatic MPO and EPO activities. Our in vitro and in vivo results suggest that R. mucilaginosa UFMGCB 18377 presents probiotic potential and deserve further studies as candidate of probiotic by-products. In addition, this is the first screening study of yeasts isolated from Antarctic environments and of Rhodotorula genus for probiotic use.

Screening of Microbes Associated With Swine Growth and Fat Deposition Traits Across the Intestinal Tract

Pigs, as one of the most common livestock species worldwide, are expected to have a fast growth rate and lower subcutaneous fatness but higher intramuscular fat ("marbling meat"). Nowadays, it is believed that not only host genetics but also its gut microbiomes can modulate farm animal phenotypes, however, many of the mechanisms remain elusive. We measured the body weight (BW), average daily gain (ADG), backfat thickness (BFT), and intramuscular fatness (IMF) of 91 Enshi pigs at 260 days of age, then genotyped each one individually using a 50K single nucleotide polymorphism array and performed 16S ribosomal RNA gene sequencing on 455 microbial samples from the jejunum, ileum, cecum, colon, and rectum. The microbial diversity showed notable spatial variation across the entire intestinal tract, with the cecum and colon having the highest α-diversity. The cecal and colonic microbiotas made greater contributions to BW and ADG and accounted for 22-37% of the phenotypic variance. The jejunal and cecal microbiotas contributed more (13-31%) to the BFT and IMF than the other segments. Finally, from cecum, colon, and jejunum, we identified eight microbial taxa that were significantly correlated with the target traits. The genera Alloprevotella and Ruminococcaceae UCG-005 were highly positively correlated with BW and ADG. The genera Prevotellaceae UCG-001 and Alistipes in the cecum and Clostridium sensu stricto 1 in the jejunum were highly positively correlated with BFT and IMF. The genera Stenotrophomonas, Sphaerochaeta, and Desulfovibrio were negatively associated with the mentioned traits. These findings could aid in developing strategies for manipulating the gut microbiota to alter production performance in pigs.