Sake yeast induces the sleep-promoting effects under the stress-induced acute insomnia in mice.

Sleep deprivation induces adverse effects on the health, productivity, and performance. The individuals who could not get enough sleep temporarily experience the symptoms of an induced acute insomnia. This study investigated the efficacy of sake yeast in treatment of acute insomnia in mice. The results of this study showed that sake yeast induced a significant dose-dependent wake reduction, a rapid eye movement (REM) and a non-REM (NREM) sleep enhancement during the first 6 h after the oral administration of sake yeast with locomotor activity and core body temperature decreases under the stressful environment in a new cage. In fact, the wake amounts at 3 h and 6 h were significantly reduced after the oral administration of sake yeast compared with the vehicle. The NREM sleep amounts at 3 h and 6 h significantly increased after the administration of sake yeast compared with the vehicle. The REM amount at 6 h significantly increased after the administration of sake yeast compared with the vehicle, but not at 3 h. The previous study suggested that the sleep-promoting effects of sake yeast could be referred from the activating effect of adenosine A2A receptor (A2AR). In summary, the sake yeast is an A2AR agonist and may induce sleep due to its stress-reducing and anti-anxiety properties. Further verification of the involvement of adenosine in the pathophysiology of insomnia is needed.

Impact of CO2 overpressure on yeast mitochondrial associated proteome during the "prise de mousse" of sparkling wine production.

The "prise de mousse" stage during sparkling wine elaboration by the traditional method (Champenoise) involves a second fermentation in a sealed bottle followed by a prolonged aging period, known to contribute significantly to the unique organoleptic properties of these wines. During this stage, CO2 overpressure, nutrient starvation and high ethanol concentrations are stress factors that affect yeast cells viability and metabolism. Since mitochondria are responsible for energy generation and are required for cell aging and response to numerous stresses, we hypothesized that these organelles may play an essential role during the prise de mousse. The objective of this study is to characterize the mitochondrial response of a Saccharomyces cerevisiae strain traditionally used in sparkling wine production along the "prise de mousse" and study the effect of CO2 overpressure through a proteomic analysis. We observed that pressure negatively affects the content of mitochondrion-related proteome, especially to those proteins involved in tricarboxylic acid cycle. However, proteins required for the branched-amino acid synthesis, implied in wine aromas, and respiratory chain, also previously reported by transcriptomic analyses, were found over-represented in the sealed bottles. Multivariate analysis of proteins required for tricarboxylic cycle, respiratory chain and amino acid metabolism revealed differences in concentrations, allowing the wine samples to group depending on the time and CO2 overpressure parameters. Ethanol content along the second fermentation could be the main reason for this changing behavior observed at proteomic level. Further research including genetic studies, determination of ROS, characterization of mitochondrial activity and targeted metabolomics analyses is required. The list of mitochondrial proteins provided in this work will lead to a better understanding of the yeast behavior under these conditions of special interest in the wine industry.

Growth, survival, and metabolic activities of probiotics Lactobacillus rhamnosus GG and Saccharomyces cerevisiae var. boulardii CNCM-I745 in fermented coffee brews.

Amidst rising demand for non-dairy probiotic foods, and growing interest in coffees with added functionalities, it would be opportune to ferment coffee brews with probiotics. However, challenges exist in maintaining probiotic viability in high-moisture food products. Here, we aimed to enhance the viability of the probiotic bacteria, Lactobacillus rhamnosus GG, in coffee brews by co-culturing with the probiotic yeast, Saccharomyces cerevisiae var. boulardii CNCM-I745. The yeast significantly enhanced the viability of L. rhamnosus GG, as bacterial populations beyond 7 Log CFU/mL were maintained throughout 14 weeks of storage at 4 and 25 °C. In contrast, the single culture of L. rhamnosus GG suffered viability losses below 6 Log CFU/mL within 10 weeks at 4 °C, and 3 weeks at 25 °C. Growth and survival of S. boulardii CNCM-I745 remained unaffected by the presence of L. rhamnosus GG. Volatile profiles of coffee brews were altered by probiotic metabolic activities, but co-culturing led to suppressed generation of diacetyl and ethanol compared to single cultures. Probiotic fermentation did not alter principal coffee bioactive compounds and antioxidant capacities; however, declines in peroxyl radical scavenging capacities were observed after ambient storage. Overall, we illustrate that yeasts are effective in enhancing probiotic bacterial viability in coffee brews, which may be useful in developing shelf stable probiotic food products.

Dietary supplementation of beta-glucan-rich molasses yeast powder on antibody response to swine fever virus and hematology of starter-grower pigs.

This research investigated the impact of dietary beta-glucan-rich molasses yeast powder (MYP) supplementation on the antibody response to swine fever virus (Titer) and hematology of starter-grower pig. Sixteen cross pigs (30 kg body weight) were equally split into four groups; each group with four replicates and fed four dietary treatments that consisted of basal diets (control) and the basal diets added with 2.5, 5.0, and 7.5% MYP. Feed and water were consumed ad libitum for 44 days. Feed intake (FI), MYP intake (MYPI), beta-glucan intake (BGI), and Mannan-oligosaccharide intake (MOSI) were recorded daily. Titer was evaluated after 15 (Titer15) and 30 (Titer30) days after vaccination, while hematology was analyzed at the end of the experiment. The results indicated that it was unchangeable for ADFI (P > 0.05). No impacts were observed on hematological variables and Titer15 in MYP fed pigs (P > 0.05). However, supplementation with 7.5% MYP increased platelet count (PC) and Titer30 (P < 0.01), but decreased hematocrit (Hct) (P < 0.05). Titer 30 and titer 15 were linked to MYPI, BGI, and MOSI (P < 0.05). Based on the study, feeding starter-grower pigs diets supplemented with 7.5% MYP might enhance the antibody response to swine fever virus 30 days after vaccination, and it has a potential role in the application in prevention of swine fever virus disease.

ESCRT machinery plays a role in microautophagy in yeast.

BACKGROUND: Microautophagy, which degrades cargos by direct lysosomal/vacuolar engulfment of cytoplasmic cargos, is promoted after nutrient starvation and the inactivation of target of rapamycin complex 1 (TORC1) protein kinase. In budding yeast, microautophagy has been commonly assessed using processing assays with green fluorescent protein (GFP)-tagged vacuolar membrane proteins, such as Vph1 and Pho8. The endosomal sorting complex required for transport (ESCRT) system is proposed to be required for microautophagy, because degradation of vacuolar membrane protein Vph1 was compromised in ESCRT-defective mutants. However, ESCRT is also critical for the vacuolar sorting of most vacuolar proteins, and hence reexamination of the involvement of ESCRT in microautophagic processes is required. RESULTS: Here, we show that the Vph1-GFP processing assay is unsuitable for estimating the involvement of ESCRT in microautophagy, because Vph1-GFP accumulated highly in the prevacuolar class E compartment in ESCRT mutants. In contrast, GFP-Pho8 and Sna4-GFP destined for vacuolar membranes via an alternative adaptor protein-3 (AP-3) pathway, were properly localized on vacuolar membranes in ESCRT-deficient cells. Nevertheless, microautophagic degradation of GFP-Pho8 and Sna4-GFP after TORC1 inactivation was hindered in ESCRT mutants, indicating that ESCRT is indeed required for microautophagy after nutrient starvation and TORC1 inactivation. CONCLUSIONS: These findings provide evidence for the direct role of ESCRT in microautophagy induction.

Effects of dietary yeast cell wall on biochemical indices, serum and skin mucus immune responses, oxidative status and resistance against Aeromonas hydrophila in juvenile Persian sturgeon (Acipenser persicus).

The present study aims to shed light on the effects of yeast cell wall (ImmunoWall®) supplementation on biochemical indices, oxidative status, serum and mucus immune responses as well as disease resistance of juvenile Persian sturgeon (Acipenser persicus). For this purpose, one hundred fifty three juvenile Persian sturgeons (47.78 ± 0.39 g) were distributed into nine tanks (500 L) and fed with basal diets containing two levels of yeast cell wall (YCW) 0.5% (T1) and 1% (T2) and a diet without YCW as control (0%). As shown by the results obtained at the end of 56-day feeding trial, YCW had no significant effect on glucose, cortisol, SGOT, lysozyme and IgM in serum (P > 0.05) albeit an enhancement of cholesterol, LDH, ALP and SOD and ACH50 was observed in fish fed YCW supplemented diets. However, plasma triglyceride levels were lower in fish fed YCW compared with the control group. Also, total protein content, lysozyme and protease activities in skin mucus were unaffected by the supplemented diets (P > 0.05) and only total immunoglobulin and ALP enzyme activity were significantly increased in T1 and T2 groups (P > 0.05). The cumulative mortality of the fish fed supplemented diets at the end of disease challenge was 100% where cumulative mortality of those fed the control diet was 75% (P < 0.05). The present study shows that increasing immune parameters in serum and mucus of juvenile Persian sturgeon by YCW dietary supplementation did not improve resistance against Aeromonas hydrophila. According to the obtained results, the YCW supplementation at 0.5 and 1% in the juvenile Persian sturgeon diet is not recommended.

Kluyveromyces marxianus: An emerging yeast cell factory for applications in food and biotechnology.

Several yeasts, which are eukaryotic microorganisms, have long been used in different industries due to their potential applications, both for fermentation and for the production of specific metabolites. Kluyveromyces marxianus is one of the most auspicious nonconventional yeasts, generally isolated from wide-ranging natural habitats such as fermented traditional dairy products, kefir grain, sewage from sugar industries, sisal leaves, and plants. This is a food-grade yeast with various beneficial traits, such as rapid growth rate and thermotolerance that make it appealing for different industrial food and biotechnological applications. K. marxianus is a respiro-fermentative yeast likely to produce energy by either respiration or fermentation pathways. It generates a wide-ranging specific metabolites and could contribute to a variety of different food and biotechnological industries. Although Saccharomyces cerevisiae is the most widely used dominant representative in all aspects, many applications of K. marxianus in biotechnology, food and environment have only started to emerge nowadays; some of the most promising applications are reviewed here. The general physiology of K. marxianus is outlined, and then the different applications are discussed: first, the applications of K. marxianus in biotechnology, and then the recent advances and possible applications in food, feed and environmental industries. Finally, this review provides a discussion of the main challenges and some perspectives for targeted applications of K. marxianus in the modern food technology and applied biotechnology in order to exploit the full potential of this yeast which can be used as a cell factory with great efficiency.

Effects of supplementing yeast fermentate in the feed or drinking water on stress susceptibility, plasma chemistry, cytokine levels, antioxidant status, and stress- and immune-related gene expression of broiler chickens.

This study aimed to elucidate the mechanism by which adding Saccharomyces cerevisiae-derived yeast fermentate to the feed (XPC) or drinking water reduces stress in poultry. Day-old male Cobb 500 broiler chicks were assigned to 1 of 3 treatments: stressed control (CS), stressed + XPC (1.25 kg/metric ton feed, day 0-43; XPC), or stressed + AviCare (160 mL/100 L drinking water, day 0-43; AVI). All birds were spray-vaccinated for coccidiosis (day 0), raised on reused litter, spray-vaccinated for Newcastle/Bronchitis (day 18), and exposed to heat stress (32°C-34°C) and feed/water withdrawal for 12 h (day 18). Blood samples were collected to assess plasma corticosterone (CORT) and heterophil/lymphocyte (H/L) ratio (60 birds/treatment; day 40); plasma biochemistry and growth hormone (12 birds/treatment; day 38); and serum serotonin and plasma prolactin, thyroid hormones, antioxidant capacity, and selected cytokines (12 birds/treatment; day 39). Composite asymmetry scores were obtained from 60 birds/treatment on day 41. Organs were collected from 20 birds/treatment on day 43 to measure gene expression of CYP1A2 and melanocortin 2 receptor (MC2R) in the adrenal glands and IL10 and AvBD1 in the spleen. Serotonin was lower in CS than XPC (P = 0.049), whereas AVI was intermediate. Plasma interleukin (IL)-1ß was higher in AVI than CS (P = 0.009) and XPC (P = 0.009). The CS treatment had higher CORT than AVI (P = 0.013) and XPC (P = 0.037) and higher H/L ratios than AVI (P = 0.026) and XPC (P = 0.034). Expression of CYP1A2, MC2R, and IL10 was lower (P < 0.05) in XPC and AVI compared with CS. Furthermore, IL10 expression was lower in XPC than AVI (P < 0.05). Adding yeast fermentate to the feed or drinking water reduced measures of stress and MC2R gene expression in birds exposed to acute and rearing stressors. However, differences in IL10 gene expression and circulating serotonin and IL-1ß suggest that supplementing yeast fermentate in the feed is slightly more effective than supplementation via the drinking water in mitigating the physiological effects associated with the stress response in broilers.

Dietary supplementation of marine yeast Yarrowia lipolytica modulates immune response in Litopenaeus vannamei.

The immunostimulatory potential of the marine yeast Yarrowia lipolytica (D1 and N6 strains) administered orally was evaluated in the white shrimp Litopenaeus vannamei. Yeasts and commercial glucans were mixed with a commercial feed to formulate diets with a 1.1% concentration of immunostimulants. The shrimp were fed daily for a period of 21 days. Weekly determinations were performed for immunological parameters in hemolymph, such as total hemocyte count (THC), lysozyme activity (LYZ), prophenoloxidase activity, antioxidant enzymatic activities (superoxide dismutase [SOD], catalase [CAT], and peroxidases), and bactericidal activity against Vibrio parahaemolyticus. Expression profiles of penaeidin (PEN), lysozyme (LYZ), and prophenoloxidase (proPO) immune genes were evaluated in hemocytes. In general, an increase in the immune parameters was observed in shrimp fed yeast diet compared to glucan and the control diets. Yarrowia lipolytica, especially strain N6, provided maximum immunostimulatory effects evidenced by the increase of immune parameters (THC, LYZ, SOD, CAT) and gene expression profile. In conclusion, this study demonstrated that Y. lipolytica had immunostimulatory effects and increased bactericidal activity in L. vannamei hemocytes against V. parahaemolyticus. These findings open the path for the potential application of Y. lipolytica-based immunostimulant for shrimp aquaculture.

Effects of dietary supplementation with vitamin E, selenium yeast or both on egg incubation response, embryonic development, keet quality, and posthatch growth of helmeted guinea fowl breeders.

This study investigated the effects of dietary supplementation with vitamin E (vit. E), selenium yeast (Se yeast), or both on egg incubation response, embryonic development, keet quality, and posthatch growth of helmeted guinea fowls. Two hundred and forty 24-week old helmeted guinea fowl hens (average weight 1.75 + 0.22 kg) and cocks (average weight 2.15 + 0.20 kg) were assigned into 24 pens; each pen housed 10 hens and 2 cocks. There were four dietary treatments consisting of a basal diet (control), basal diet supplemented with vit. E (30 IU/kg), Se yeast (0.3 mg/kg Se), or both. Six pens were assigned to each treatment. Egg incubation response were estimated using 504 settable eggs sampled from each treatment collected during 15 to 17 weeks in lay. A total of 72 fertile eggs sampled from each treatment were used for the estimation of embryonic development. Quality of day-old keets hatched was scored based on physical conditions, while posthatch growth was measured for 21 days. Guinea fowl breeders fed diet supplemented with both vit. E and Se yeast produced the highest (P < 0.05) number of fertile eggs, percentage fertility, number of hatchlings, hatchability of total eggs, and hatchability of fertile eggs. Supplementation with vit. E + Se yeast resulted in the heaviest (P < 0.05) embryo weight, relative embryo weight, least (P < 0.05) yolk sac weight, and relative yolk sac weight on 25 days of incubation. Hatchlings from breeders fed diet supplemented with Se yeast and vit. E + Se yeast showed normal swallowed yolk. Supplementation of maternal diet with vit. E, Se yeast, and vit. E + Se yeast resulted in improved (P < 0.05) feed conversion ratio of subsequent hatchlings during 1 to 7-day posthatch growth. It can be concluded that dietary supplementation of vit. E + Se yeast in guinea fowl breeders resulted in improved egg fertility, hatchability, heavier embryo weights, hatchlings of good quality, and improved posthatch growth during the first 7 days.

The effect of a selected yeast fraction on the prevention of pullorum disease and fowl typhoid in commercial breeder chickens.

A selected yeast fraction (SYF) was tested for the purpose of preventing pullorum disease and fowl typhoid in breeder chickens. In a challenge-protection experiment, commercial Three-Yellow breeder chicks were initially divided into groups A, B (challenged, treated), C (challenged, untreated), and D (unchallenged, untreated). The group A diet was supplemented with SYF and group B was supplemented with Acidipure via drinking water. At 7 D, birds of groups A, B, and C were divided into 2 equal subgroups (A1-A2, B1-B2, and C1-C2). Subgroups A1, B1, and C1 were challenged with Salmonella pullorum (SP), while subgroups A2, B2, and C2 were challenged with Salmonella gallinarum (SG). Clinical signs and mortality were recorded daily. At intervals, antibodies against SP and SG were detected by a plate agglutinate test (PAT). At 42 D, all birds were weighed and necropsied, lesions were recorded and challenge pathogens were isolated. Results showed that SP and SG isolation positive rates of groups A1-A2 were significantly lower (P < 0.05) than those of B1-B2 and C1-C2, respectively. The average body weight (BW) of groups A1-A2 was significantly higher (P < 0.05) than that of B1-B2 and C1-C2, respectively. In the field trial, chicks were randomly divided into 3 groups. Group 1 birds were fed a diet supplemented with SYF, group 2 diet was supplemented with Acidipure via drinking water, and group 3 was fed the same but un-supplemented diet as the control group. Antibodies against SP and SG were detected by PAT at 120 D. The antibodies positive rate of group 1 was significantly lower (P < 0.05) than those of groups 2 and 3, while no significant difference (P > 0.05) was found between groups 2 and 3. The results demonstrated that SYF supplementation could significantly decrease SP and SG infection rates, improve the BW of birds challenged with SP and SG, and was more effective than Acidipure via drinking water.

Effects of dietary yeast culture on shrimp growth, immune response, intestinal health and disease resistance against Vibrio harveyi.

The current study was conducted to evaluate the effects of different levels of yeast culture (YC) supplementation at 0% (YC 0%), 1% (YC 1%), and 2% (YC 2%) on growth, feed conversion ratio, body composition, intestinal morphology, microflora, immune response, and resistance to Vibrio harveyi infection in Litopenaeus vannamei. After 8-weeks feeding trial, the results showed significant improvement (p < .05) in the final weight, weight gain rate, specific growth rate, survival rate and low feed conversion ratio in YC groups than the control. Serum total protein, superoxide dismutase, catalase, alkaline phosphatase, acid phosphatase, lysozyme, and phenol oxidase in shrimps fed diet YC (2%) were significantly higher (p < .05), whereas significantly decreased trend in serum cholesterol, triglyceride, aspartate aminotransferase, and alanine aminotransferase (p < .05) were observed in YC (2%) diet. Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes were the core phylum bacteria found in the shrimp intestines. At the genus level, opportunistic pathogenic bacteria, Vibrio was significantly decreased (p < .05) while beneficial bacteria Pseudoalteromonas was increased in YC (2%) group. Intestinal villus height and width in shrimps fed YC diets were significantly improved than the control diet (p < .05). YC groups challenged test significantly showed (p < .05) improved shrimps immune response against V. harveyi infections with YC (2%) recording the highest percentage survival rate (70%). The present study demonstrated that supplementing YC (2%) can improve growth, intestinal microbiota, intestinal morphology, and immune response against V. harveyi infections in L. vannamei.

Yeast culture promotes the production of aged laying hens by improving intestinal digestive enzyme activities and the intestinal health status.

Yeast culture (YC) positively affects the performance of laying hens. The purpose of the present study was to explore the underlying mechanism for the YC-mediated performance improvement. Sixty 67-week-old Hy-Line Brown laying hens were randomly allocated into 2 experimental groups with 5 replicates of 6 birds each. One group was fed a control diet, whereas the other received the control diet supplemented with YC at 3.0 g/kg; treatment lasted for 8 wk. The results showed that dietary YC supplementation increased (P < 0.05) the total egg weight (11.2-13.6%) and egg-laying rate (13.0-13.5%) but decreased (P < 0.05) the feed/egg ratio by 9.3 to 11.0% during weeks 5 to 6 and 7 to 8 compared with the control. However, egg quality, including eggshell strength, eggshell thickness, egg weight, albumen height, egg yolk color, and Haugh unit, was not affected (P > 0.05) by YC supplementation. Furthermore, dietary YC supplementation increased (P < 0.05) chymotrypsin and ɑ-amylase activities by 54.8 to 62.5% in the duodenal chyme and reduced (P < 0.05) plasma endotoxin by 44.1%. YC dietary supplementation also upregulated (P < 0.05) the mRNA levels of intestinal barrier-related genes (occludin and claudin 1) and antimicrobial peptides genes (ß-defensin 1 and 7 and cathelicidin 1 and 3) in the duodenum or jejunum compared with the control. In conclusion, dietary YC supplementation improved the performance of aged laying hens, potentially through the upregulation of intestinal digestive enzyme activities and intestinal health-related gene expression.

The effects of dietary yeast hydrolysate on growth, hematology, antioxidant enzyme activities and non-specific immunity of juvenile Nile tilapia, Oreochromis niloticus.

The present study was aimed to compare and evaluate the impacts of supplemented diets with different yeast hydrolysate (YH) levels on growth performance, body composition, hematological characteristics, antioxidant enzyme activities, and non-specific immunity (intestinal cytokines) of juvenile Nile tilapia (Oreochromis niloticus). Three isonitrogenous (protein, 33%) and isolipidic (lipid, 6%) experimental diets supplemented graded levels of YH (0% for control; 1% and 3% as tested diets) were fed to juvenile Nile tilapia. A total of 240 fish with initial body weight averaging 3.5 ± 0.02 g were randomly divided into three groups with four replicates per group and 20 fish for each replicate. For apparent satiation, the fish were fed twice daily during eight weeks. The results showed no significant difference in survival among all treatments. The fish fed the diet containing 1% yeast hydrolysate had significantly elevated weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) compared to the control group and lower feed conversion ratio (FCR). The fish fed 1% and 3% YH showed higher glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) activity and a significantly lower malondialdehyde (MDA) level in the liver than the control group, indicating enhancement of the anti-oxidant status. Serum lysozyme activity was significantly increased in the diet having 1% and 3% yeast hydrolysate supplementation groups, suggesting an improvement influence on the non-specific immune response. The expression of IL-1ß, IL-10, TNF-α, TGF-ß2, ALP and TLR2 was significantly elevated in fish fed the diet containing 1% YH. In conclusion, dietary supplementation with 1% yeast hydrolysate improves growth performance, and feed utilization enhances the antioxidant status and exerts an adequate stimulus on the non-specific immunity (intestinal cytokines) of Nile tilapia.

Volatile metabolites produced by different flor yeast strains during wine biological ageing.

Sherry white wine called Fino is produced by dynamic biological ageing under the action of flor yeasts using traditional practices aimed at ensuring uniform quality and characteristics over time. These kinds of yeasts provide typical sensory properties to Fino wines. Although there are studies of the volatile composition of these wines submitted to biological ageing in wood barrels, there is a lack of knowledge on the particular volatile profile produced by different flor yeast strains from Sherry zone wineries. For this reason, the aim of this study was to analyse the volatile profiles produced by 15 pure culture flor velum yeasts, with the goal of observing their suitability for obtaining high quality Fino sherry wines. Volatile composition was determined by dual sequential stir bar sorptive extraction, followed by GC-MS analysis. All yeast strains studied produced the increase of most acetals, highlighting acetaldehyde diethylacetal which was the compound that most increased. Among terpenes, nerolidol and farnesol underwent remarkable increases. However, results showed that in a month of biological ageing, significant differences were observed among the volatile metabolites produced by flor yeast strains studied. Only some of them stood out for their high production of volatile compounds characteristic of Sherry Fino wines, which are good candidates for producing starter cultures.

Organic acids produced during fermentation and sensory perception in specialty coffee using yeast starter culture.

Volatile and non-volatile compounds in coffee directly affect the beverage's quality. This study aimed to demonstrate how the organic acids and volatile profiles were impacted by coffee fermentation using four starter cultures (Meyerozyma caribbica (CCMA 0198), Saccharomyces cerevisiae (CCMA 0543), Candida parapsilosis (CCMA0544), and Torulaspora delbrueckii (CCMA 0684)) inoculated in two varieties of coffee (Bourbon Amarelo and Canário Amarelo) using natural and pulped natural processing methods and sensory perception. Real-time PCR (qPCR) was used to verify the dynamic behavior of yeast populations. Organic acids were detected using high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) was used to detected volatile compounds. Sensory analysis was performed on the roasted coffee. Citric, malic, succinic, lactic, oxalic, isobutyric, and propionic acids and 105 volatile compounds were detected. At the beginning of fermentation, treatments with natural processing presented higher number of volatiles compounds. After fermentation, the main compounds groups were acids, alcohols, and aldehydes. The perception of sensory attribute (fruity, nutty, cocoa) varied with the coffee variety, type of processing, and type of inoculum. The use of yeasts is an alternative for sensorial differentiation of coffee variety Canário Amarelo and Bourbon Amarelo. The stainless-steel containers showed good results for coffee fermentation.

Performance, carcass characteristics and meat quality of Nellore cattle supplemented with supranutritional doses of sodium selenite or selenium-enriched yeast.

The enrichment of meat with selenium is important to improve the intake of selenium by humans. The effects of supranutritional doses of sodium selenite or selenium-enriched yeast on performance, carcass characteristics and meat quality were evaluated using 63 Nellore cattle in a completely randomized design with two sources (sodium selenite and selenium-enriched yeast), three levels (0.3, 0.9 and 2.7 mg Se/kg DM) and control treatment (without addition of selenium). Final body weight (BW), average daily gain, dry matter intake and gain to feed ratio (G : F) at the end of 84 days of supplementation were not influenced by treatments (P>0.05). Values of pH, ribeye area, back fat thickness and marbling score were also not influenced by treatments ( P>0.05). Dressing percentage was greater (P=0.02) in Nellore cattle supplemented with organic Se (58.70%) compared to animals supplemented with inorganic Se (57.94%). Hot carcass weight increased ( P=0.05) with the increasing of Se levels in the diet. Colour, shear force (SF), cooking and drip loss remained unchanged ( P>0.05); however thiobarbituric acid reactive substances was 15.51% higher with inorganic Se compared with organic Se. The selenium concentration in the meat of animals receiving organic selenium was higher ( P<0.001) than that of animals receiving sodium selenite, at all levels (0.3; 0.9 and 2.7 mg/kg DM). The meat of animals receiving 2.7 mg of organic Se/kg of DM presented concentration of 372.7 µg Se/kg in the L.dorsi muscle, and the intake of 150 g of this meat by humans provides approximately 100% of the recommended Se intake (55 µg Se/day for adults). Therefore, the use of supranutritional doses of 2.7 mg Se/kg of DM, regardless of source, is a way of naturally producing selenium-enriched meat without compromising performance, carcass characteristics and quality of Nellore bovine meat.

Effects of Yeast Autolysate in the Practical Diet on the Growth Performance, Immune Response, and Disease Resistance of Pacific White Shrimp.

The present study was conducted to investigate the effects of supplementing the practical diet with yeast autolysate (YA) on the growth performance, immunity, and disease resistance of Pacific white shrimp Litopenaeus vannamei. Four isonitrogenous and isolipidic practical diets were formulated. The relatively high-fish-meal control diet contained 25% fish meal without YA supplementation (E1). The other control diet contained 20% fish meal without YA (E2). With the E2 diet as the basis, two additional experimental diets were created by further supplementation with 1% YA (E3) and 2% YA (E4). The shrimp (initial weight: 0.30 ± 0.02 g) were fed with the four experimental diets for 8 weeks and then challenged with Vibrio parahaemolyticus. The results indicated that there were no significant differences in survival rate (SR) or feed intake (FI) among these groups. The weight gain rate (WGR) of group E1 was not significantly different from that of groups E3 and E4. The feed conversion ratio (FCR) in group E4 was lower than that of group E2, and group E4 had the highest protein efficiency ratio (PER). The total hemocyte counts (THC) and lysozyme activities in group E3 and group E4 were significantly higher than those of the other groups. Group E3 had the highest respiratory burst (RB). After V. parahaemolyticus administration, group E3 and group E4 had significantly lower cumulative mortalities than group E1 did. In conclusion, the 20% fish meal diet without YA supplementation (E2) yielded a significantly lower growth rate than the 25% fish meal diet without YA supplementation (E1) did. Furthermore, the Pacific white shrimp that received dietary supplementation with 1% YA demonstrated improved growth rate, immune response, and resistance to the V. parahaemolyticus challenge compared with those that were fed the 20% fish meal diet without YA supplementation (E2).

Effects of dietary Pediococcus acidilactici GY2 single or combined with Saccharomyces cerevisiae or/and ß-glucan on the growth, innate immunity response and disease resistance of Macrobrachium rosenbergii.

One Pediococcus acidilactici strain, named PA-GY2 was isolated from the gut of cultured Macrobrachium rosenbergii. In order to better examine the potential scope and applicability of this strain in M. rosenbergii culture, based on the control diet, four experimental diets containing single or combined immunostimulants were produced by supplementing with yeast (Saccharomyces cerevisiae, SC) or/and ß-glucan (G), then fed to the prawns (6.70 g ± 0.74) in five groups, which were named as group C (control group), P (PA-GY2), PS (PA-GY2 + SC, 1:1), PG (PA-GY2 + G) and PGS (PA-GY2 + SC + G), respectively. After a 60-day feeding trial, growth performance, feed utilization, immune response and disease resistance of prawns were evaluated in the present study. Results indicated that (1) The growth performance of the prawns in group PS and PGS were significantly improved. The prawns in group PGS presented the lowest feed coefficiency (FC), while prawns in group C presented the highest FC. (2) The protease activity was significantly improved by dietary immunostimulants supplementation, meanwhile, prawns in the group PS presented the highest lipase activity. (3) The highest total hemocyte count and respiratory burst activity were found in the group P and PG, respectively. The phagocytic index of the prawns in the group C was significantly lower than those in group P and PGS. (4) Dietary PA-GY2 single or combined with SC or/and ß-glucan increased the immune related genes expression, including some antibacterial and antioxidant enzymes, while decreased the tumor necrosis factor-α gene expression, which led to the decreased cumulative mortality rate of prawns during the Aeromonas hydrophila challenge test. Based on the results of growth performance, digestive enzymes activity and immune response of M. rosenbergii, PA-GY2 supplementation, single or combined with SC or/and ß-glucan could be suggested as promising immunostimulants in prawns farming.

Subchronic effects of dietary selenium yeast and selenite on growth performance and the immune and antioxidant systems in Nile tilapia Oreochromis niloticus.

Selenium is an essential element but toxic at high levels in animals. The effects of Se on growth performance and the immune system in Nile tilapia remain inconclusive. In this study, Nile tilapia Oreochromis niloticus was fed on selenium yeast (Se(Y))- and selenite (Se(IV))-enriched feed at 0, 3, 6, and 12 µg/g (dry wt) for 45 and 90 d. The growth, bioaccumulation, biochemical markers related to antioxidant, immunological, nervous and digestive systems were evaluated in various fish tissues (liver, intestine, kidney, muscle, brain, spleen, gills). The results showed that the accumulation of Se(Y) was 1.3-2 folds of Se(IV) in most tissues. The growth of tilapia was enhanced by both Se(Y) and Se(IV) at 3 µg/g after 90 d, with Se(Y) better than Se(IV) in tilapia feed. After 45 d, the levels of lipid peroxidation, the activity of the antioxidant enzymes, and the transcriptional levels of the immune related genes (IL-1ß, IFN-γ and TNF-α) and stress proteins (HSP70 and MT) were enhanced in all treatments, except that of MT in the 12 µg/g Se(Y) group. In addition, both Se species inhibited the activity of acetylcholinesterase (AChE) in the brain and one digestive enzyme α-glucosidase (α-Glu) in the intestine at 12 µg/g. However, after 90 d, the effects on most biochemical markers were less pronounced, implying a possible acclimation after prolonged duration. The results demonstrate Se is beneficial to O. niloticus at low levels and toxic at elevated levels. The immunostimulation by Se might be greatly weakened after long term feeding Se-enriched feed. This study helps to better understand the effects of Se on the antioxidant and immune systems and to establish the optimal Se levels in the feed and duration for O. niloticus.