Yeasts and Yeast-based Products in Poultry Nutrition

Enhancing Laying Hen Productivity and Health: Influence of Dietary Probiotic Bacillus Strains and Prebiotic Saccharomyces cerevisiae Yeast Cell Wall on Production Performance, Egg Quality, and Inflammatory Responses

To evaluate the influences of dietary Bacillus-based probiotics and yeast-based prebiotics over 16 weeks, 500 37-week-old Hisex white layers were indiscriminately assigned to five dietary groups: T1, control; T2, control + Bacillus subtilis (1.1 × 108 CFU/kg); T3, control + Bacillus subtilis and Bacillus licheniformis (1.3 × 109 CFU/kg); T4, control + Bacillus coagulans (1.0 × 109 CFU/kg); and T5, control + Saccharomyces cerevisiae yeast cell wall (0.25 g/kg). Cumulatively (p < 0.001), T1 showed the highest feed consumption, while T4 and T5 had higher egg production than T1 and T3. T3 yielded the heaviest eggs, whereas T2 produced the lightest. Egg mass was higher in T3, T4, and T5, with all supplemented groups showing improved feed conversion ratios compared to the control. Furthermore, T5 showed a higher wet yolk weight (p < 0.001), while T2 and T5 had a higher dry albumin weight (p < 0.05). Additionally, T3, T4, and T5 reduced serum IL-1β (p < 0.05), IL-6 (p < 0.01), and TNF-α (p < 0.01), alongside elevated IL-10 levels (p < 0.01) relative to the control. Overall, the results suggest that dietary supplementation with multi-strain combinations and yeast-derived prebiotics can enhance both productivity and immune health in laying hens.

Cecal microbiome in broiler chicken related to antimicrobial feeding and bird's sex

This study investigated the cecal microbiome of broilers raised under specific antimicrobial feeding programs (AFPs). A total of 2304 day-old Ross-708 male (M, n = 1152) and female (F, n = 1152) chicks were distributed into 48 floor pens which were allocated to one of three AFPs: Conventional, raised without medically important antibiotics (RWMIA), and raised without antibiotics (RWA). At 28 (D28) and 41 (D41) days of age, cecal contents were collected for culture dependent and independent analyses. At both 28 and 41 days, Enterococcus was more abundant in RWA-raised broilers than other groups with the most abundance of this bacterium being found in female birds (P < 0.05). At D41, the most abundant Eimeria tenella counts was observed in RWA-raised broiler ceca (P < 0.05). Sex effects were observed on the abundances of four of the 248 identified antimicrobial resistance genes while abundances of 10 were modulated by AFPs (P < 0.05). Ceca of females birds showed more tssB than males, and ceca of RWMIA-raised birds contained the highest abundance of chuY genes regardless of sex. This study showed that in a specific feeding program, cecal resistome can be affected by chicken's sex contributing to understand the AMR related to the AMU.

Yeast mixture supplementation modulates faecal microbiota and ileum morphology of weaning pigs

Different yeast strains benefit postweaning piglets by promoting intestinal health. The objective of this study was to investigate the effect of a yeast mixture containing Kluyveromyces marxianus fragilis, Pichia guilliermondii, and Saccharomyces cerevisiae (Vetoquinol italia s.r.l., Italy) on gut health parameters and growth performance traits of weaned piglets. Forty-eight postweaning castrated male piglets (27 ± 1.7 days, 7.19 ± 0.54 kg) were randomly allocated to two homogeneous experimental groups and involved in a 28-day trial. Both the groups received a basal diet with (yeast mixture, YM) or without (control, CTR) the inclusion of 0.8% yeast mixture during weeks 1 and 2, and 0.6% during weeks 3 and 4. Individual BW and box feed intake were determined on days 0, 14, and 28, and average daily gain and Gain:Feed ratio were subsequently calculated for each administration period (0-14, 14-28). Individual faecal samples were collected for microbiota analysis on days 4, 14, 21, and 28, and faecal score was evaluated on the same days. At the end of the trial, 12 piglets for each group were sacrificed, and ileal tissue was sampled for morphological analysis and the evaluation of mucins profile, using Alcian-Blue/Periodic Acid-Shiff (PAS) staining. On ileum samples, dividing and differentiated epithelial cells were also identified using proliferating cell nuclear antigen and alkaline phosphatase expression, respectively. Differences in the means between the experimental groups were determined by ANOVA, while the metataxonomics analyses were performed by sequencing for V3 and V4 hypervariable regions of the 16S rRNA gene. Growth performance traits were not different among the two experimental groups when considering the whole trial period, while treated animals showed increased faecal consistency on weeks 1 and 4 (P = 0.036 and 0.021, respectively). Yeast mixture administration increased the abundance of Bifidobacterium (P = 0.006) and Coprococcus 2 (P = 0.015), and decreased Clostridium Sensu Stricto 1 (P = 0.019) at all the considered timepoints. Ileum villous height, villous width, and crypt depth were significantly increased by yeast mixture supplementation (P = 0.019; P = 0.013; P = 0.036, respectively), while no differences were observed for the villous:crypt ratio among the groups. The mucin profile showed no differences among experimental groups for acid and neutral glycoconjugates. However, a higher presence of PAS-positive mucins was highlighted in the villi of YM piglets (P < 0.001) compared to CTR. Overall, the administration of a yeast mixture to postweaning piglets showed positive effects on gut health when compared to piglets not receiving the tested product, improving beneficial genera and intestinal morphology.

Yeast Proteins: Proteomics, Extraction, Modification, Functional Characterization, and Structure: A Review

Proteins are essential for human tissues and organs, and they require adequate intake for normal physiological functions. With a growing global population, protein demand rises annually. Traditional animal and plant protein sources rely heavily on land and water, making it difficult to meet the increasing demand. The high protein content of yeast and the complete range of amino acids in yeast proteins make it a high-quality source of supplemental protein. Screening of high-protein yeast strains using proteomics is essential to increase the value of yeast protein resources and to promote the yeast protein industry. However, current yeast extraction methods are mainly alkaline solubilization and acid precipitation; therefore, it is necessary to develop more efficient and environmentally friendly techniques. In addition, the functional properties of yeast proteins limit their application in the food industry. To improve these properties, methods must be selected to modify the secondary and tertiary structures of yeast proteins. This paper explores how proteomic analysis can be used to identify nutrient-rich yeast strains, compares the process of preparing yeast proteins, and investigates how modification methods affect the function and structure of yeast proteins. It provides a theoretical basis for solving the problem of inadequate protein intake in China and explores future prospects.

Feeding a Novel Mannan-Rich Yeast Carbohydrate Product Improves Production Performance and Humoral Immunity of Broiler Chickens

The current study examined the benefits of a novel mannan-rich yeast carbohydrate product (YM) on broiler chicken growth performance and immune response against sheep red blood cells (SRBCs). A total of 144 newly hatched male Cornish cross broiler chicks were randomly assigned to four treatments with 12 cages per treatment and three birds per cage. The treatments were (1) control, basal diet; (2) YCW, basal diet + 1 g/kg yeast cell wall; (3) YM1, basal diet + 0.5 g/kg of a novel yeast mannan-rich product (YM); and (4) YM2, basal diet + 1 g/kg YM. Growth performance was measured at 14, 28, and 35 days of age (d). At 26 and 27 d, nine birds per treatment were immunized intravenously with SRBCs, and antibody responses against SRBCs were analyzed through a hemagglutination assay 7 days post-inoculation. Supplementing YM tended to improve broiler chicken weight gain from 29 to 35 d (p = 0.053). An improvement in the feed conversion ratio (FCR) was observed in the birds fed YM diets during 29-35 d and over the entire experimental period (0-35 d; p < 0.05). Furthermore, birds fed YM2 diets had more robust antibody responses against SRBCs than the control birds (p = 0.033). In conclusion, dietary supplementation of YM improved broiler chicken growth performance and antibody response against SRBCs.

Impact of dietary-nucleotides and Saccharomyces cerevisiae-derivatives on growth-performance, antioxidant-capacity, immune-response, small-intestine histomorphometry, caecal-Clostridia, and litter-hygiene of broiler-chickens treated with florfenicol

Stress in poultry production is energy-demanding. Nucleotides and yeast cell-wall products are essential nutrients for broiler performance, gut function, and immune response. Antibiotics, like florfenicol, negatively affect the immune system. A total of 600 one-d-old broiler chickens (Cobb-500) were weighed and randomly allotted into four groups with three replicates each. The control group (G1) received the basal diet, G2 received a diet supplemented with a combination of nucleotides and Saccharomyces cerevisiae derivatives (250 g/Ton), G3 received the basal diet and medicated with florfenicol (25 mg/Kg body weight) in drinking water for 5 days, while G4 received a combination of nucleotides and Saccharomyces cerevisiae-derivatives (250 g/Ton) and medicated with florfenicol in drinking water. Growth performance criteria were recorded weekly. Blood, intestinal contents, small-intestine sections, and litter samples were collected to measure birds' performance, carcass yields, leukocytic counts, antioxidant capacity, antibody titres, phagocytic index, caecal Clostridia, intestinal histomorphometry, and litter hygiene. Nucleotide-supplemented groups (G2 and G4) revealed significant (p ≤ 0.05) improvements in feed conversion, and body weight, but not for carcass yields in comparison to the control. Dietary nucleotides in G2 elevated blood total proteins, leucocytic count, antioxidant capacity, and phagocytic index, while they lowered blood lipids and litter moisture and nitrogen (p ≤ 0.05). Dietary nucleotides in G4 ameliorated the immunosuppressive effect of florfenicol (p ≤ 0.05) indicated in reducing caecal Clostridia, improving duodenal and ileal villi length, and increasing blood albumin and globulin levels, and phagocytosis%. Supplementing diets with nucleotides and yeast products has improved the immune system and provided a healthier gut for broilers.

Salmonella Infection in Poultry: A Review on the Pathogen and Control Strategies

Salmonella is the leading cause of food-borne zoonotic disease worldwide. Non-typhoidal Salmonella serotypes are the primary etiological agents associated with salmonellosis in poultry. Contaminated poultry eggs and meat products are the major sources of human Salmonella infection. Horizontal and vertical transmission are the primary routes of infection in chickens. The principal virulence genes linked to Salmonella pathogenesis in poultry are located in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2). Cell-mediated and humoral immune responses are involved in the defense against Salmonella invasion in poultry. Vaccination of chickens and supplementation of feed additives like prebiotics, probiotics, postbiotics, synbiotics, and bacteriophages are currently being used to mitigate the Salmonella load in poultry. Despite the existence of various control measures, there is still a need for a broad, safe, and well-defined strategy that can confer long-term protection from Salmonella in poultry flocks. This review examines the current knowledge on the etiology, transmission, cell wall structure, nomenclature, pathogenesis, immune response, and efficacy of preventative approaches to Salmonella.