Dietary Yeast Research Articles

Effects of dietary yeast culture on health status in digestive tract of juvenile Pacific white shrimp Litopenaeus Vannamei

A feeding trial was conducted to investigate the effects of dietary yeast culture (YC) on health status in digestive tract of juvenile Pacific white shrimp Litopenaeus Vannamei. Shrimps (initial weight: 3.33 ± 0.06 g) were fed with graded levels of dietary YC (control, 0.3%, 0.5% and 1.0%). Results of the present study showed that villus height and the ratio between villus height and crypt depth in the digestive tract of juvenile shrimp was significantly increased by dietary 0.5% and 1.0%YC (P < 0.05). Besides, dietary 0.5% and 1.0%YC significantly activities of phenoloxidase (PO), lysozyme (LZ), acid phosphatase (ACP) and alkaline phosphatase (AKP) (P < 0.05), significantly up-regulated mRNA levels of prophenoloxidase (propo), lysozyme (lz), anti-lipopolysaccharide factor (alf), crustin and penaienadin (P < 0.05) and down-regulated mRNA levels of caspase-1, nuclear factor κB p65 (nf-κbp65) myeloid differentiation primary response protein (myd88) and toll like receptor (tlr) in the digestive tract of juvenile shrimp (P < 0.05). Compared with the control, dietary 0.5%YC increased Chao1 index in the digestive tract of juvenile shrimp. In addition, compared with the control, dietary 0.5% and 1.0%YC significantly increased relative abundance of Lactobacillus (P < 0.05). It can be concluded that dietary YC made positive contribution to health status in digestive tract of juvenile shrimp through improving morphology and microbiota, enhancing immune function, and inhibiting inflammation of digestive tract.

An Evaluation of Yeast Culture Supplementation in the Diet of Pseudobagrus ussuriensis: Growth, Antioxidant Activity, Nonspecific Immunity, and Disease Resistance to Aeromonas hydrophila

An 8-week feeding trial was conducted to evaluate the effects of dietary yeast culture (YC) supplementation on growth performance, antioxidant activity, nonspecific immunity, and disease resistance of Pseudobagrus ussuriensis (average initial weight6.01±0.01 g). Four isonitrogenous and isolipidic diets were formulated to contain 0 (Y0), 10 (Y1), 20 (Y2), and 30 (Y3) g/kg YC, respectively. After the feeding experiment, the challenge test of injecting Aeromonas hydrophila was executed. Results showed that appropriate YC supplementation level in the diet could improve growth performance, digestive enzyme activities, nonspecific immunity capacity, antioxidant capacity, and disease resistance of P. ussuriensis. And the highest weight gain, feed intake, specific growth rate, and IGF-1 gene expression level were observed in fish fed the Y2 diet. The activities of protease and amylase in intestine in fish fed the Y2 diet were enhanced compared with that in fish fed the Y0 diet significantly (P&lt;0.05). Simultaneously, fish fed the Y2 diet had significantly higher serum lysozyme activity and significantly lower serum alanine amino transferase activity (P&lt;0.05). Dietary 20 g/kg YC supplementation increased the activity of catalase and total antioxidant capacity in liver and reduced malondialdehyde content in the liver and intestine of P. ussuriensis significantly (P&lt;0.05). Fish fed the Y2 diet had the highest disease resistance under the condition of A. hydrophila challenge (P&lt;0.05). The quadratic regression analysis based on weight gain against dietary YC levels indicated that the appropriate dietary YC supplementation level is 13.4 g/kg diet.

Effects of dietary supplementation with selenium yeast and jujube powder on mitochondrial oxidative damage and apoptosis of chicken

The main objective of this study was to explore the effects of dietary selenium yeast and jujube powder on mitochondrial oxidative damage and cell apoptosis of broilers during postmortem aging, chicken breasts of broilers fed diets supplemented with different concentrations of selenium yeast and jujube powder were used as research subjects. With the prolongation of postmortem aging time, the levels of reactive oxygen species (ROS), carbonyl content, mitochondrial permeability transition pore (MPTP) openness, and mitochondrial membrane permeability increased significantly (P < 0.05). The contents of the sulfhydryl, mitochondrial membrane potential, shear force, and cytochrome C (Cyt-c) reduction level decreased significantly (P < 0.05). The activity of Caspase-3 and Caspase-9 increased from 0 to 24 h postmortem but fell from 24 to 72 h postmortem. Compared with the control group, dietary selenium yeast and jujube powder significantly reduced mitochondrial oxidative damage. They greatly increased the shear force, mitochondrial membrane potential, and Cyt-c reduction levels (P < 0.05). Among them, the combination group of high-dose selenium yeast and jujube powder had more significant effects on ROS scavenging, reducing cell membrane permeability, protecting cell membrane integrity, and increasing Cyt-c reduction level (P < 0.05). In conclusion, cell apoptosis intensifies during the chicken breast's aging time, and muscle tenderness continues. Still, different doses of dietary selenium yeast and jujube powder can inhibit mitochondrial oxidation to various degrees. The combined group of selenium yeast and jujube powder with 0.6 mg·kg−1 has the best effect. This study is of great significance for applying natural antioxidant ingredients such as selenium yeast and jujube powder in the development and utilization of poultry feed.

Bacterial Metabolism and Transport Genes Are Associated with the Preference of Drosophila melanogaster for Dietary Yeast.

Many animal traits are influenced by their associated microorganisms ("microbiota"). To expand our understanding of the relationship between microbial genotype and host phenotype, we report an analysis of the influence of the microbiota on the dietary preference of the fruit fly Drosophila melanogaster. First, we confirmed through experiments on flies reared bacteria-free ("axenic") or in monoassociation with two different strains of bacteria that the microbiota significantly influences fruit fly dietary preference across a range of ratios of dietary yeast:dietary glucose. Then, focusing on microbiota-dependent changes in fly dietary preference for yeast (DPY), we performed a metagenome-wide association (MGWA) study to define microbial species specificity for this trait and to predict bacterial genes that influence it. In a subsequent mutant analysis, we confirmed that disrupting a subset of the MGWA-predicted genes influences fly DPY, including for genes involved in thiamine biosynthesis and glucose transport. Follow-up tests revealed that the bacterial influence on fly DPY did not depend on bacterial modification of the glucose or protein content of the fly diet, suggesting that the bacteria mediate their effects independent of the fly diet or through more specific dietary changes than broad ratios of protein and glucose. Together, these findings provide additional insight into bacterial determinants of host nutrition and behavior by revealing specific genetic disruptions that influence D. melanogaster DPY. IMPORTANCE Associated microorganisms ("microbiota") impact the physiology and behavior of their hosts, and defining the mechanisms underlying these interactions is a major gap in the field of host-microbe interactions. This study expands our understanding of how the microbiota can influence dietary preference for yeast (DPY) of a model host, Drosophila melanogaster. First, we show that fly preferences for a range of different dietary yeast:dietary glucose ratios vary significantly with the identity of the microbes that colonize the fruit flies. We then performed a metagenome-wide association study to identify candidate bacterial genes that contributed to some of these bacterial influences. We confirmed that disrupting some of the predicted genes, including genes involved in glucose transport and thiamine biosynthesis, resulted in changes to fly DPY and show that the influence of two of these genes is not through changes in dietary ratios of protein to glucose. Together, these efforts expand our understanding of the bacterial genetic influences on a feeding behavior of a model animal host.

Function of yeast extract in greater wax moth farming: does yeast extract always improve the development and reproduction of insects?

TheGalleria mellonella L. (Lepidoptera: Pyralidae) has great nutritional potential for humans and animals and is currently used as a model organism in many biological studies, despite its damage to the apicultural industry and wild honeybee colonies. Yeast extract that promotes insect development and reproduction by containing many necessary nutrients has always been an important yet expensive ingredient in the majority of artificial diets forG. mellonella. To better understand the influence of yeast extract content onG. mellonella mass-rearing, the life table parameters fromG. mellonella mass-reared on increasing amounts of yeast (0% in control, 2, 4, 6, 7, and 9% of the total diet, respectively) under laboratory conditions were analysed according to age-stage, two-sex life table theory. Harvest rate and recruitment cost to produce 10,000 pupae were also assessed to help identify an economically sustainable rearing system. The intrinsic rate of increase (r) and finite rate of increase (λ) varied among diets. Highest values found in theG. mellonella population reared on a 9% yeast extract diet did not differ significantly from those of diets consisting of 4, 6, and 7% yeast extract, whereas these parameters were lowest in yeast-free artificial diets. The cheapest daily cost of rearing a population was 3,966.57 CNY (Chinese Yuan), and the heaviest pupal weight for both females and males (398.10±9.26 and 316.00±7.92 mg, respectively) were found with an artificial diet of 4% yeast extract. This study demonstrates that excessive dietary yeast extract is not always beneficial toG. mellonella. The most effective yeast extract percentage inG. mellonella mass-rearing diets is about 4% based on life table parameters, computer projection, and harvesting costs.

Effects of Dietary Yeast β-Glucan Supplementation on Meat Quality, Antioxidant Capacity and Gut Microbiota of Finishing Pigs.

Yeast β-glucan is a natural antioxidant and has been reported to improve growth performance of piglets, but its application in improving pork quality is limited. This study investigated the effects of dietary yeast β-glucan supplementation on meat quality, antioxidant capacity and gut microbiota of finishing pigs. In a 40-day experiment, ninety finishing pigs (Duroc × Landrace × Yorkshire, 70.47 ± 0.04 kg) were randomly allocated into five treatments including a basal diet supplemented with 0, 50, 100, 200 and 400 mg/kg yeast β-glucan. Results showed that yeast β-glucan significantly increased pH45 min (linear and quadratic, p < 0.01) and a*45 min (linear, p < 0.05), and reduced cooking loss (linear, p < 0.05) and drip loss (quadratic, p < 0.05) of meat in finishing pigs. Importantly, the 200 mg/kg group exhibited the highest values of pH45 min (p < 0.01) and the lowest values of drip loss (p < 0.05), accompanied by a decreased lactate content (p < 0.05) and glycolytic potential (p < 0.05). Dietary supplementation of 200 mg/kg yeast β-glucan markedly increased catalase (CAT) (p < 0.05), superoxide dismutase (SOD) (p < 0.05) and total antioxidant capacity (T-AOC) (p < 0.01) activities in skeletal muscle. Moreover, WPS-2 abundance was decreased significantly in colonic digesta by 200 mg/kg yeast β-glucan and exhibited a positive association with muscle lactate content and drip loss. Together, dietary 200 mg/kg yeast β-glucan supplementation effectively improved pH value and the water-holding capacity of fresh meat through reducing muscle postmortem glycolysis, increasing antioxidant capacity and altering the gut microbiota composition of finishing pigs.

Comparative evaluation of the impact of feeding live yeast and sodium bicarbonate to high-yielding cows on their productivity and milk quality

High productivity of dairy cows is due to genetics, especially during the first phase of lactation and is manifested by appropriate feeding, namely a significant amount of concentrates in their diet. However, such feeding has a significant disadvantage – lowering the pH in the rumen and the development of acidosis. In order to prevent the development of this pathological process, various buffer supplements are introduced into the diet of cows, including live yeast and baking soda. Therefore, the aim of the study was to experimentally evaluate the effect of sodium bicarbonate and live yeast Levucell SC on the productivity and milk quality of dairy cows during the first phase of lactation. During the scientific and economic experiment, the main period of which lasted 76 days, the animals of the control group received a basic diet without feed additives. Cows of the 2nd experimental group to the basic diet were added live yeast Levucell SC in the amount of 1 g/head/day, and the 3rd experimental group – sodium bicarbonate at a dose of 150 g/head/day. According to the results of the experiment, it was noted that the highest milk productivity was recorded in animals of the 2nd experimental group (41.9 kg/day), while in the control this figure was 37.3 kg/day. Changes in productivity and cows of the 3rd experimental group of 39.8 kg / day were positive. A similar trend occurred in the fat content of milk, somatic cell content and bacterial contamination. According to all these indicators, the best results were recorded in cows of the 2nd experimental group, which consumed live yeast. Economic analysis of the results of the experiment showed that despite the very high cost of feed additive Levucell SC, a small dose of its introduction is more profitable than the use of sodium bicarbonate. The additional income from the introduction of Levucell SC in the diet of live yeast at 2022 prices is 95 kopecks, while in the group of cows that consumed sodium bicarbonate, this figure is only 41 kopecks. Key words: live yeast, Levucell SC, sodium bicarbonate, baking soda, milk yield, acidosis.

Saccharomyces Boulardii Ameliorates Non-alcoholic Steatohepatitis in Mice Induced by a Methionine-Choline-Deficient Diet Through Gut-Liver Axis.

Non-alcoholic steatohepatitis (NASH) is affecting people worldwide. Changes in the intestinal microbiome are crucial to NASH. A previous study showed that eradicating intestinal fungi ameliorates NASH; however, the role of intestinal fungi in the development of NASH remains unclear. Saccharomyces boulardii (SB), a dietary supplement yeast, has been reported to restore the integrity of the intestine. Here, we tested the effect of SB in the treatment of NASH. For this study, we fed eight-week-old C57/BL6 male mice either a methionine-choline deficient (MCD) diet or a normal chow diet (NCD) for eight weeks. Half of the MCD diet-fed mice were gavaged with SB (5 mg/day) once daily. The remainder of the NCD–fed mice were gavaged with normal saline as a control. The MCD diet-fed mice on SB supplement showed better liver function, less hepatic steatosis, and decreased inflammation. Both hepatic inflammatory gene expression and fibrogenic gene expression were suppressed in mice with SB gavage. Intestinal damage caused by the MCD diet was tampered with, intestine inflammation decreased, and gut permeability improved in mice that had been given the SB supplement. Deep sequencing of the fecal microbiome showed a potentially increased beneficial gut microbiota and increased microbiota diversity in the SB-supplemented mice. The SB supplement maintains gut integrity, increases microbial diversity, and increases the number of potentially beneficial gut microbiota. Thus, the SB supplement attenuates gut leakage and exerts a protective effect against NASH. Our results provide new insight into the prevention of NASH.

Effect of dietary yeast culture supplementation on the cecal microbiota modulation of geese

One of the most extensively applied animal feed additives is yeast culture ( YC ), which can increase production efficiency by altering gastrointestinal tract ( GIT ) microbiota. Geese are the ideal model to study the interaction between diet and GIT, due to their adaptation to consume different roughage sources. Here, we fed geese with 0 (control), 0.5% (treat1), 1.0% (treat2), 2.0% (treat3), and 4.0% (treat4) of YC for 10 wk. The GIT microbiota was analyzed by 16S rRNA gene V3–V4 region via high-throughput sequencing. The results showed that YC supplementation did not significantly affect α-diversity ( P >0.05). However, dietary YC at 2.0% had the highest species richness (quadratic, P < 0.05). Principal coordinates analysis showed an obvious separation between control and 4.0% group. The dominant phyla were Firmicutes and Bacteroidetes whereas the predominant genera were Alistipes and Desulfovibrionaceae . The relative abundance of phyla Firmicutes significantly increased in 0.5, 1.0, and 2.0% group and decreased in 4.0% group ( P < 0.05). YC supplementation increased the relative abundance of Bacteroidetes (linear, P = 0.04) and genus Bacteroides (linear, P = 0.02; quadratic, P = 0.05). 1.0% group contained the highest proportion of the beneficial bacteria, such as Parabacteroides, Enterococcus, Streptococcus , and Pseudomonas . 0.5% group obviously improved the capacity of amino acid and carbohydrate metabolism. Collectively, these findings demonstrate the beneficial effects of YC feeding on gut microbiota for geese, which suggested that dietary strategy based on feed additives is an effective method to maintain the health of geese.

P214. Enzymatically treated yeast in diets of weanling pigs

P214. Enzymatically treated yeast in diets of weanling pigs

Effects of Yeast Culture Supplementation on Growth Performance, Nutrient Digestibility, Blood Metabolites, and Immune Response in Geese.

Simple SummaryAntibiotics benefit animal growth performance and health. However, an overuse of antibiotics can lead to antibiotic residue and the development of drug-resistant bacteria. Considering the possible serious consequences of antibiotic overuse, non-antibiotic alternatives, such as yeast and yeast products, are widely used in animal diets to improve growth and productive performance. Geese are important poultry, and their meat provides high-quality protein to humans, but studies showing how yeast culture affect geese are limited. On this basis, the effects of dietary yeast culture supplementation on growth performance, nutrient digestibility, blood metabolites, and immune functions of geese were studies. The results showed that the dietary addition of yeast culture could improve growth performance and nutrient digestibility and can modulate the immune response of geese. This dietary strategy based on feed additives is an effective method for improving the growth efficiency of the geese.The present study was conducted to investigate the effects of dietary yeast culture (YC) supplementation on growth performance, nutrient digestibility, blood metabolites, and immune functions in geese. One-day-old Sichuan white geese (n = 300) were randomly divided into five groups containing 0 (control), 0.5%, 1.0%, 2.0%, and 4.0% of YC in the diet for 70 days. In general, the dietary supplementation of YC significantly increased the average daily gain and feed conversion ratio (p < 0.05) in which the 1.0% or 2.0% levels were better and significantly reduced the average daily feed intake at the 2.0% level (p < 0.05). YC supplementation increased digestibility of P (quadratic, p = 0.01) and gross energy (quadratic, p = 0.04) from days 23 to 27 and crude protein from days 23 to 27 and days 64 to 68 (quadratic, p ≤ 0.05), with the 2.0% level being the most effective. Serum metabolites were significantly affected by dietary YC (p < 0.05). Supplemental YC increased IL-2 on day 28 (linear, p = 0.01; quadratic, p = 0.04) and lysozyme on day 70 (quadratic, p = 0.04) and decreased complement C4 on day 70 (linear, p = 0.05). Interferon-γ, interleukin-2, and tumor necrosis factor-α genes were mostly up-regulated after YC supplementation, and interferon-γ and interleukin-2 gene expression levels were significantly increased at the 2.0% level (p < 0.05). Taken together, dietary YC supplementation improved growth performance and affected nutrient digestibility, serum metabolites, and immune function in geese, which was optimized at the 2% YC level in the present study.

A combination of red structural and pigmentary coloration in the eyespot of a copepod.

While the specific mechanisms of colour production in biological systems are diverse, the mechanics of colour production are straightforward and universal. Colour is produced through the selective absorption of light by pigments, the scattering of light by nanostructures or a combination of both. When Tigriopus californicus copepods were fed a carotenoid-limited diet of yeast, their orange-red body coloration became faint, but their eyespots remained unexpectedly bright red. Raman spectroscopy indicated a clear signature of the red carotenoid pigment astaxanthin in eyespots; however, refractive index matching experiments showed that eyespot colour disappeared when placed in ethyl cinnamate, suggesting a structural origin for the red coloration. We used transmission electron microscopy to identify consecutive nanolayers of spherical air pockets that, when modelled as a single thin film layer, possess the correct periodicity to coherently scatter red light. We then performed microspectrophotometry to quantify eyespot coloration and confirmed a distinct colour difference between the eyespot and the body. The observed spectral reflectance from the eyespot matched the reflectance predicted from our models when considering the additional absorption by astaxanthin. Together, this evidence suggests the persistence of red eyespots in copepods is the result of a combination of structural and pigmentary coloration.

Effects of dietary chromium yeast levels on growth performance, anti-oxidative capacity, immune response and flesh quality of abalone Haliotis discus hannai

A 110-day feeding trial was conducted to investigate the effects of dietary chromium (Cr) on the growth performance, immune response, anti-oxidative capacity, stress resistance, flesh quality of abalone Haliotis discus hannai. Seven isonitrogenous and isolipidic experimental diets were formulated with graded levels of Cr (0.04, 0.67, 1.21, 1.58, 2.21, 2.72 and 3.33 mg/kg) from Cr yeast. The results showed that weight gain rate (WGR) was highest in the group with 1.21 mg/kg of dietary Cr. Based on the broken-line regression analysis for WGR, the dietary Cr requirement of abalone was estimated to be 1.32 mg/kg. With the increase of dietary Cr level from 0.04 to 1.21 mg/kg, the total anti-oxidative capacity and lysozyme activity in the cell-free hemolymph were increased and then decreased when the dietary Cr level exceeded 1.21 mg/kg. After the challenge of Vibrio parahaemolyticus, the cumulative mortality of abalone was significantly decreased in the group with 1.21 mg/kg of dietary Cr compared with that in the control group. Meanwhile, after the heat stress test, the cumulative mortality of abalone was significantly reduced in the groups with 1.58, 2.21 and 2.72 mg/kg of dietary Cr compared with that in the control group. The liquid and water loss of foot muscle were significantly increased in the groups with 2.72 and 3.33 mg/kg of dietary Cr. With the increase of dietary Cr levels, the hardness of foot muscle was significantly elevated. The chewiness of foot muscle was significantly increased with the increase of dietary Cr level from 0.04 to 1.21 mg/kg, and thereafter showed no significant difference when dietary Cr exceeded 1.21 mg/kg. In conclusion, based on the WGR, dietary Cr requirement of abalone (initial weight: 22.31 ± 0.31 g) was estimated to be 1.32 mg/kg. Appropriate dietary Cr levels (1.21–1.58 mg/kg) had positive effects on growth performance, immune response, anti-oxidation, anti-stress and flesh quality of abalone. Overhigh dietary Cr level (2.72–3.33 mg/kg) decreased the flesh quality. Excessive dietary Cr level (3.33 mg/kg) had a negative effect on the health of abalone.

Effects of yeast culture supplementation from late gestation to weaning on performance of lactating sows and growth of nursing piglets

Dietary yeast culture supplementation can contribute to the performance and health of sows and piglets, but few studies have focused on the relationships between the effects of yeast culture and gut microbiota. This study investigated the effect of yeast culture (Saccharomyces cerevisiae) supplementation from late gestation to weaning on the reproductive performance of lactating sows and their faecal microbiota. One hundred and six purebred Landrace sows, of parities two to six were selected and randomly assigned to a control (CON) and yeast culture supplementation (YC) groups based on parity and back fat thickness. The YC sows were individually fed with yeast culture at a dose of 24 g/d from day 90 of gestation to parturition and 40 g/d during lactational period. Blood samples were collected from sows on d 110 of gestation and at weaning at day 21 of lactation for plasma hormone and immunoglobulin analysis. Colostrum and milk on day 20 of lactation were collected for composition analysis. Faecal samples from sows on day 110 of gestation and day 20 of lactation were collected for short-chain fatty acid and faecal microbial analysis. Results showed that the farrowing performance of YC sows did not differ significantly from the CON group (P > 0.05). The average daily feed intake by the YC group during the lactation period was significantly increased by 9.98% (P = 0.004), the weaning-to-oestrus interval was shortened by 0.96 d (P = 0.046) and average daily weight gain of piglets increased by 7.14% (P = 0.036) compared with the CON group. Yeast culture supplementation also significantly improved the average daily milk yield in the first week of lactation (P = 0.035), lactose content in colostrum (P = 0.046), protein (P = 0.033) and DM (P < 0.001) content of milk. In the YC group, concentrations of plasma ghrelin (P = 0.02) and IgG (P = 0.015) were increased compared with the CON group, while that of glucagon-like peptide-1 was decreased (P = 0.006) on d 110 of gestation. The 16S rRNA gene sequencing showed that faecal microbiota changed at taxonomic levels with yeast culture addition (P < 0.05). Dietary yeast culture supplementation from late gestation to lactation improved feed intake, immunity status, milk yield, milk quality and faecal microbiota of sows, resulting in the improved growth performance of piglets.

Meta-analysis to evaluate the effect of yeast as a feed additive on beef cattle performance and carcass traits

Yeast (Saccharomyces cerevisiae) is a group of feed additives widely used in ruminant diets to improve rumen health and consequently animal performance. The present study evaluated the effect of yeast inclusion on beef cattle's performance and carcass traits by meta-analysis. We hypothesized that the variables experimental period, supply period, and statistical design affect beef cattle's performance and carcass traits supplemented with yeast. Thirty-one peer-reviewed publications with 106 treatment means were included in the data set. Yeast effect as an additive in beef cattle diets was evaluated by examining the weighted mean differences (WMD) between yeast treatment (diets with yeast inclusion as an additive) and control treatment (diet with no additive). Heterogeneity was explored by meta-regression and subgroup analysis using genetic group, experimental design, experimental period, yeast in diet (g/day), yeast type, feeding system, and concentrate in diet (g/kg of dry matter). The experimental period was the variable that most influenced the variability of responses with yeast in the diet. Yeast addition in the diets increased average daily gain (ADG; WMD= 0.03 kg/d; P = 0.001) and carcass weight (WMD=3.12 kg; P = 0.046). The experimental period and yeast supply for up to 90 days increased the animals’ final body weight. The effect of yeast inclusion in the diet on the variable final body weight was only affected by the inclusion period or yeast supply. For the other ADG, carcass weight, and dressing, the response's variation was dependent only on the level of yeast inclusion in the diet. The diet's inclusion levels between 10 and 15 g yeast/day increase average daily gain and carcass weight.

Local non-food yeast protein in pig production–environmental impacts and land use efficiency

The aim of this study was to analyse the sustainability of pig production based on a diet containing yeast as a protein source. The yeast is produced from sugar, and the sugar can be produced from hydrolysed wood through a biorefinery process. This study included yeast from two different biorefinery processes: 1) a domestic demo plant in connection with a complex biorefinery, and 2) a small-scale wood refinery process largely based on wood residues. In the yeast diets, the yeast replaced soybean meal as a protein source and the two yeast diets were compared with a standard diet. The environmental impacts from the pig production systems were assessed by using life cycle assessment (LCA), and the functional unit was 1 kg carcass weight of pork at the farm gate.The results from the study show that yeast replacing imported feed protein sources used in pig production gives a lower impact for biodiversity loss and climate change including land use change . The lower impact was created by the replacement of soybean meal with yeast from wood sugar in the feed recipe. Also, the scenarios with yeast diets gave a land use ratio below 1, indicating an improved land use efficiency regarding producing human digestible protein. Even though the forest land used for deriving wood sugar constitutes a greater area than the corresponding area for soybean meal production, the forest land does not occupy areas suitable for food production. The reference case, representing current pig production and feeding system, had a land use ratio of 1.15, meaning that the feed production was directly competing for the area suitable for food production.The overall conclusion was that the utilisation of yeast from wood sugar appears to avoid feed-food competition and at the same time to be an environmentally sustainable solution for future feed protein employed in pig production.

Drosophila Sirtuin 6 mediates developmental diet-dependent programming of adult physiology and survival.

Organisms in the wild experience unpredictable and diverse food availability throughout their lifespan. Over‐/under‐nutrition during development and in adulthood is known to dictate organismal survival and fitness. Studies using model systems have also established long‐term effects of developmental dietary alterations on life‐history traits. However, the underlining genetic/molecular factors, which differentially couple nutrient inputs during development with fitness later in life are far less understood. Using Drosophila and loss/gain of function perturbations, our serendipitous findings demonstrate an essential role of Sirtuin 6 in regulating larval developmental kinetics, in a nutrient‐dependent manner. The absence of Sirt6 affected ecdysone and insulin signalling and led to accelerated larval development. Moreover, varying dietary glucose and yeast during larval stages resulted in enhanced susceptibility to metabolic and oxidative stress in adults. We also demonstrate an evolutionarily conserved role for Sirt6 in regulating physiological homeostasis, physical activity and organismal lifespan, known only in mammals until now. Our results highlight gene‐diet interactions that dictate thresholding of nutrient inputs and physiological plasticity, operative across development and adulthood. In summary, besides showing its role in invertebrate ageing, our study also identifies Sirt6 as a key factor that programs macronutrient‐dependent life‐history traits.

Understanding metabolic phenomena accompanying high levels of yeast in broiler chicken diets and resulting carcass weight and meat quality changes

The use of yeast as a protein source was investigated in broiler chicken diets on carcass quality, storage stability, and metabolite changes in leg meat. Male Ross 308 chickens (n = 100) were fed with one of 5 diets: control, control added 0.6% formic acid, or 3 diets where soybean meal was substituted with 10, 20, and 30% crude protein from inactivated yeast Cyberlindnera jadinii (CJ10, CJ20, CJ30, respectively). The yeast-containing diets reduced carcass weight, linoleic acid, and warm-over flavor in chicken leg meat. Protein degradation-related metabolite biomarkers were upregulated in the leg of chickens that were fed yeast-containing diets, indicating an adaptive response to the loss of appetite. Chill-stored leg meat of birds fed yeast diets showed increased browning and metallic taste compared with those fed the control diet. The use of formic acid in the diet reduced cooking loss and had a positive effect on vitamin B content.

Effect of different feeds on reproduction performance, nutritional components and fatty acid composition of cladocer water flea ( Daphnia magna )

This research evaluated the growth, survival, proximate and fatty acid composition of water flea (Daphnia magna) fed baker's yeast (BY) and three types of microalgae diets. In this study, two freshwater microalgae; Botrycoccus braunii (BB) and Chlorella vulgaris (CV), one marine spray-dried microalgae, Nannochloropsis oculata (SDN), and baker's yeast were evaluated for herbivorous zooplankton Daphnia magna. Survival, reproduction and population density of Daphnia magna have been studied. Daphnia reproduction was enhanced by utilization of baker's yeast diet with increasing egg number, juvenile and adult female numbers among treatments during the experimental period. Daphnia fed SDN diet increased egg number only 7th day of experiment. Population density and survival was positively affected by utilization of baker's yeast at the end of the experiment. Protein levels enhanced by SDN diets while Daphnia fed Botrycoccus braunii diet showed the highest lipid and EPA content in Daphnia. Overall, each diet improved different part of nutrients in Daphnia biomass.

Dietary live yeast supplementation alleviates transport-stress-impaired meat quality of broilers through maintaining muscle energy metabolism and antioxidant status.

BACKGROUNDThis experiment was to investigate the effect of dietary live yeast (LY, 1 × 1010 CFU g−1) supplementation on serum metabolic parameters, meat quality as well as antioxidant enzyme activity of transported broilers. A total of 192 one‐day‐old broilers were randomly assigned to four treatments with six replicates and eight chicks per replicate: a basal diet without transportation (CON), a basal diet containing 0 (T), 500 (T + LY500) and 1000 mg kg−1 (T + LY1000) LY with 3 h of transportation after feeding for 42 days, respectively. The serum and muscle samples of broilers were collected immediately after 3 h of transportation.RESULTSA higher (P < 0.05) final body weight and average daily weight gain were observed in T + LY1000 group compared with CON and T groups. The T + LY1000 group reduced (P < 0.05) the serum lactate contents and improved (P < 0.05) the pH24h and decreased (P < 0.05) the drip loss in muscles of transported‐broilers. Also, the T + LY1000 group enhanced (P < 0.05) the total‐antioxidant capacity and reduced (P < 0.05) the malondialdehyde in serum and muscles. Besides, the messenger RNA (mRNA) expression of avian uncoupling protein (avUCP) in muscles was down‐regulated (P < 0.05) of T + LY1000 group compared with T group.CONCLUSIONDietary LY supplementation alleviates transport‐stress‐impaired meat quality of broilers through maintaining muscle energy metabolism and antioxidant status. Therefore, LY may serve as a potential protector for broilers under transport stress in the future. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.