Live yeast supplementation altered the bacterial community's composition and function in rumen and hindgut and alleviated the detrimental effects of heat stress on dairy cows.

The objective of this study was to investigate the effects of live yeast (LY, Saccharomyces cerevisiae) on the lactation performance, bacterial community, and functions in the rumen and hindgut of dairy cows under heat stress. Thirty-three multiparous (parity 3.9 ± 0.8) Holstein dairy cows (189.1 ± 6.6 d in milk at the beginning of the experiment) were randomly assigned to three groups (11 cows per treatment). Cows in the three groups were fed a diet without yeast (CON), with 10 g yeast/d/head (LY-10), and with 20 g yeast/d/head (LY-20). The yeast product contained 2.0 × 1010 CFU/g. Supplementing LY decreased the rectal temperature and respiratory rate of cows, and increased dry matter intake, milk yield, milk fat yield, milk protein yield, and milk lactose yield (P < 0.001), yet decreased milk urea nitrogen concentration (P = 0.035). Interaction effects of treatment × week were observed for rectal temperature (P < 0.05), respiratory rate (P < 0.05), milk yield (P = 0.015), milk urea nitrogen (P = 0.001), milk protein yield (P = 0.008), and milk lactose yield (P = 0.030). In rumen, LY increased the concentrations of acetate, isobutyrate, isovaterate, valerate, total volatile fatty acids (VFAs), and NH3-N (P < 0.05). Miseq sequencing of the 16S rRNA genes showed that LY increased the relative abundance of Prevotella and Prevotellaceae UCG-003 at the genus level with a series of enriched pathways in the metabolism of carbohydrates and protein. In fecal samples, LY did not affect the profile of VFAs (P > 0.05). Clostridium sensu stricto 1 (P = 0.013) and Actinobacillus (P = 0.011) increased in the relative abundance by LY, whereas Bacteroides (P = 0.016) and Oscillospirales UCG-010 (P = 0.005) decreased with a series of enriched pathways in carbohydrate metabolism, secondary bile acid biosynthesis. In summary, LY supplementation altered the bacterial community's composition and function in rumen and hindgut, and simultaneously alleviated the detrimental effects of heat stress on dairy cows. These findings provide extended insight into the effects of LY in the rumen and hindgut of dairy cows exposed to heat stress.

Dairy cows are exposed to severe heat stress under hot and humid climates in summer in south China, resulting in a decline in feed intake and milk yield. Therefore, we investigated the effect of live yeast (LY, Saccharomyces cerevisiae) supplementation on the milk performance, bacterial community, and functions in the rumen and hindgut of dairy cows under heat stress. Thirty-three dairy cows were randomly assigned to control (CON, without yeast addition), treatment 1 (LY-10, with 10 g yeast/d/head) and treatment 2 (LY-20, with 20 g yeast/d/head). Supplementing LY decreased the rectal temperature and respiratory rate of the dairy cows and increased feed intake and milk performance. Live yeast enhanced fermentation in the rumen but did not affect it in the hindgut. Live yeast altered the microbiota in the rumen and hindgut, with an enrichment of bacteria in the pathways of the metabolism of carbohydrates, protein, and other substances. In all, LY supplementation had beneficial effects on dairy cows under heat stress by affecting the microbiota and fermentation in the rumen and hindgut.

Fermented soybean meal modified the rumen microbiome to enhance the yield of milk components in Holstein cows.

The study was conducted to evaluate the rumen microbiota as well as the milk composition and milk component yields of Holstein cows supplemented with fermented soybean meal (FSBM). Eighteen Holstein cows in their 2nd parity with 54.38 ± 11.12 SD days in milking (DIM) were divided into two dietary groups (CON and TRT) of nine cows per group. The cows in the TRT group received 300 g of FSBM per cow per day in addition to the conventional diet, while each cow in the CON group was supplemented with 350 g of soybean meal (SBM) in their diet daily throughout the 28-day feeding trial. Rumen bacterial composition was detected via 16S rRNA sequencing, and the functional profiles of bacterial communities were predicted. Milk composition, milk yield, as well as rumen fermentation parameters, and serum biochemistry were also recorded. The inclusion of FSBM into the diets of Holstein cows increased the milk urea nitrogen (MUN), milk protein yield, fat corrected milk (FCM), and milk fat yield while the milk somatic cell count (SCC) was decreased. In the rumen, the relative abundances of Fibrobacterota, and Spirochaetota phyla were increased in the TRT group, while the percentage of Proteobacteria was lower. In addition, the supplementation of FSBM to Holstein cows increased the acetate percentage, rumen pH, and acetate to propionate ratio, while the proportion of propionate and propionate % was observed to decrease in the TRT group. The KEGG pathway and functional prediction revealed an upregulation in the functional genes associated with the biosynthesis of amino acids in the TRT group. This enrichment in functional genes resulted in an improved synthesis of several essential amino acids including lysine, methionine, and branch chain amino acids (BCAA) which might be responsible for the increased milk protein yield. Future studies should employ shotgun metagenomics, transcriptomics, and metabolomics technology to investigate the effects of FSBM on other rumen microbiomes and milk protein synthesis in the mammary gland in Holstein cows. KEY POINTS: • The supplementation of fermented soybean meal (FSBM) to Holstein cows modified the proportion of rumen bacteria. • Predicted metabolic pathways and functional genes of rumen bacteria revealed an enrichment in pathway and genes associated with biosynthesis of amino acids in the group fed FSBM. • The cows supplemented with FSBM record an improved rumen fermentation. • Cows supplemented with FSBM recorded an increased yield of milk protein and milk fat.

Response of Milk Performance, Rumen and Hindgut Microbiome to Dietary Supplementation with Aspergillus oryzae Fermentation Extracts in Dairy Cows.

Fungal additives had beneficial effects on milk performance in dairy cows. Previous studies investigating the effects of fungal additives mainly focused on the rumen, such influences on the hindgut remain limited. This study aimed to investigate the effects of Aspergillus oryzae fermentation extracts (AOE) on the milk performance and microbiome in the rumen and hindgut using 16S rRNA gene sequencing. Twenty lactating multiparous Holstein cows were randomly assigned to control and treatment (5 g AOE per cow per day). The results showed that AOE increased the milk yield, milk protein and lactose concentration, but did not affect the milk fat concentration. Feeding AOE did not affect the ruminal VFA pattern, pH, NH3-N, and microbial cell protein production, but decreased lipopolysaccharide concentration and tended to decrease lactate concentration. The addition of AOE increased the fecal pH and the proportions of propionate, isovalerate and valerate, and decreased the acetate to propionate ratio. PCoA analysis showed that AOE did not affect the overall ruminal bacterial population composition. Only three genera changed slightly in relative abundance. In the feces, PCoA analysis showed that AOE changed the bacterial population composition. Feeding AOE increased the relative abundances of Ruminococcaceae UCG-010 and unclassified Clostridiales vadinBB60 group, and decreased Christensenellaceae R-7 group, unclassified Muribaculaceae, Prevotellaceae UCG-001 and Romboutsia. Spearman correlation showed unclassified Clostridiales vadinBB60 group was positively correlated with propionate proportion. Overall, we present that AOE not only functioned in rumen, but also in hindgut. The hindgut microbiome changes might play an important role in the milk performance improvement of dairy cows.

Non-aqueous capillary electrophoresis for simultaneous separation and determination of three major active components in traditional medicinal preparations.

A simple and sensitive non-aqueous capillary electrophoresis method has been developed for simultaneous assay of three bioactive components (puerarin, daidzein and wogonin) in three traditional medicinal preparations for the first time. Optimum separation of the analytes was obtained on a 47 cm x 75 microm i.d. capillary using a non-aqueous buffer system of 20% acetonitrile, 25 mm ammonium acetate and apparent pH 9.00, with applied voltage and capillary temperature of 20 kV and 16 degrees C, respectively. The relative standard deviations (RSDs) of the migration times and the peak areas of the three analytes were in the ranges 2.5--4.0% and 3.2--3.9%, respectively. Detection limits of puerarin, daidzein and wogonin were 0.090, 0.145 and 0.090 microg mL(-1), respectively. In the tested concentration range, good linear relationships (correlation coef fi cients: 0.9998 for puerarin, 0.9998 for daidzein and 0.9978 for wogonin) between peak areas and concentrations of the analytes were observed. This method has been successfully applied to simultaneous determination of the three bioactive components with recoveries from 91.0 to 114.0%.

Micellar electrokinetic chromatography with laser-induced fluorescence detection for sensitive determination of ephedrine and pseudoephedrine.

A selective and sensitive micellar electrokinetic chromatography method with laser-induced fluorescence detection was developed for the quantification of ephedrine (E) and pseudoephedrine (PE) derivatized with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole. After conducting a series of optimizations, a running buffer of 10 mM sodium borate + 16 mM SDS was used for separation of the derivatives. A linear relationship for E and PE was obtained in the range of 0.044-6.6 microg mL(-1) (correlation coefficient: 0.9943 for E, 0.9946 for PE), and the detection limits for E and PE were 0.70 and 0.30 ng mL(-1), respectively. The sensitivity of E and PE was improved by several multiples of ten over those of CZE-LIF method. The method was applied to the analysis of the two alkaloids in ephedra herbal medicine and preparations with recoveries in the range of 98.3-107.1%.

Simultaneous determination of some active ingredients in anti-viral preparations of traditional Chinese medicine by micellar electrokinetic chromatography.

A simple and rapid micellar electrokinetic chromatography method was developed for the simultaneous determination of quercetin, gentiopicrin, forsythin, chlorogenic acid and caffeic acid in anti-viral preparations of traditional Chinese medicine (apTCM). In this method, the effects of buffer pH, concentration of the borax and SDS, organic modifiers, applied voltage and temperature on the separation were tested and discussed. The results showed that the fi ve analytes could be well separated within 11 min under conditions of 40 mM borax (pH 9.65) containing 20 mM SDS, 20 kV, at 25 degrees C. In the tested concentration range, regression equations revealed good linear relationships (correlation coefficients 0.9920-0.9991) between the peak areas and corresponding concentrations. In addition, a multiple linear regression QSPR model was constructed to predict the migration times of the analytes and the results were satisfactory. The method was validated by analysis of the five compounds in three representative apTCM samples with recoveries ranging from 89.2 to 106.6%.

Microemulsion electrokinetic chromatography with laser-induced fluorescence detection for sensitive determination of ephedrine and pseudoephedrine.

A selective and sensitive microemulsion electrokinetic chromatography with laser-induced fluorescence detection method was developed for the quantification of ephedrine (E) and pseudoephedrine (PE) derivatized with 4-chloro-7-nitrobenzo-2-oxa-1, 3-diazol. By a series of optimization, a running buffer composed of 20 mM borate + microemulsion (23.3 mM Sodium dodecyl sulfate/180.85 mM 1-butanol/16.4 mM n-heptane) +8% acetonitrile was applied for the separation of the derivatives. A linear relationship for E and PE was obtained in the range of 0.058-11.58 microg.mL(-1) (correlation coefficient: 0.9993 for E, 0.9995 for PE), and the detection limits for E and PE were 5.3 and 3.9 ng.mL(-1). The method was applied to the analysis of the two alkaloids in Chinese traditional herbal preparations with recoveries in the range of 96.9-105.4%.

Sensitive determination of ephedrine and pseudoephedrine by capillary electrophoresis with laser-induced fluorescence detection.

A CE-LIF method was developed for the separation and sensitive detection of ephedrine and pseudoephedrine after derivatization by 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol (NBD-C1). The derivatization and separation conditions were investigated in detail and the optimum conditions were obtained. Under the optimum experiment conditions, good linearity relationships (correlation coefficients: 0.9942 for ephedrine and 0.9970 for pseudoephedrine) between the peak heights and concentrations of the analytes were obtained (0.7-140 microM). The detection limits were 0.16 microM for ephedrine and 0.17 microM for pseudoephedrine, which indicated that the sensitivities were at least ten times improved over those reported in the literature obtained by UV detection. The method was applied to the analysis of ephedrine and pseudoephedrine in ephedra herb plants and preparations with good results.

Capillary electrophoresis with field-enhanced stacking for rapid and sensitive determination of strychnine and brucine.

A new capillary electrophoresis procedure with field-enhanced stacking concentration for the analysis of strychnine and brucine is established. After optimization of the separation and concentration conditions, the two alkaloids can be separated within 5 min and quantified with high sensitivity (The detection limits were 1.0 ng mL(-1) for strychnine and 1.4 ng mL(-1) for brucine). The method was useful for qualitative and quantitative analysis of strychnine and brucine in Strychnos nux-vomica L with recovery of 105.1% for strychnine and 98.4% for brucine.