Blood and milk metabolites of Holstein dairy cattle for the development of objective indicators of a subacute ruminal acidosis.

OBJECTIVE: The purpose of this study was to perform a comparative analysis of metabolite levels in serum and milk obtained from cows fed on different concentrate to forage feed ratios. METHODS: Eight lactating Holstein cows were divided into two groups: a high forage ratio diet (HF; 80% Italian ryegrass and 20% concentrate of daily intake of dry matter) group and a high concentrate diet (HC; 20% Italian ryegrass and 80% concentrate) group. Blood was collected from the jugular vein, and milk was sampled using a milking machine. Metabolite levels in serum and milk were estimated using proton nuclear magnetic resonance and subjected to qualitative and quantitative analyses performed using Chenomx 8.4. For statistical analysis, Student's t-test and multivariate analysis were performed using Metaboanalyst 4.0. RESULTS: In the principal component analysis, a clear distinction between the two groups regarding milk metabolites while serum metabolites were shown in similar. In serum, 95 metabolites were identified, and 13 metabolites (include leucine, lactulose, glucose, betaine, etc.) showed significant differences between the two groups. In milk, 122 metabolites were identified, and 20 metabolites (include urea, carnitine, acetate, butyrate, arabinitol, etc.) showed significant differences. CONCLUSION: Our results show that different concentrate to forage feed ratios impact the metabolite levels in the serum and milk of lactating Holstein cows. A higher number of metabolites in milk, including those associated with milk fat synthesis and the presence of Escherichia coli in the rumen, differed between the two groups compared to that in the serum. The results of this study provide a useful insight into the metabolites associated with different concentrate to forge feed ratios in cows and may aid in the search for potential biomarkers for subacute ruminal acidosis.

Comparison of metabolites in rumen fluid, urine, and feces of dairy cow from subacute ruminal acidosis model measured by proton nuclear magnetic resonance spectroscopy.

OBJECTIVE: In this study, metabolites that changed in the rumen fluid, urine and feces of dairy cows fed different feed ratios were investigated. METHODS: Eight Holstein cows were used in this study. Rumen fluid, urine, and feces were collected from the normal concentrate diet (NCD) (Italian ryegrass 80%: concentrate 20% in the total feed) and high concentrate diet (HCD) groups (20%: 80%) of dairy cows. Metabolite analysis was performed using proton nuclear magnetic resonance (NMR) identification, and statistical analysis was performed using Chenomx NMR software 8.4 and Metaboanalyst 4.0. RESULTS: The two groups of rumen fluid and urine samples were separated, and samples from the same group were aggregated together. On the other hand, the feces samples were not separated and showed similar tendencies between the two groups. In total, 160, 177, and 188 metabolites were identified in the rumen fluid, urine, and feces, respectively. The differential metabolites with low and high concentrations were 15 and 49, 14 and 16, and 2 and 2 in the rumen fluid, urine, and feces samples, in the NCD group. CONCLUSION: As HCD is related to rumen microbial changes, research on different metabolites such as glucuronate, acetylsalicylate, histidine, and O-Acetylcarnitine, which are related to bacterial degradation and metabolism, will need to be carried out in future studies along with microbial analysis. In urine, the identified metabolites, such as gallate, syringate, and vanillate can provide insight into microbial, metabolic, and feed parameters that cause changes depending on the feed rate. Additionally, it is thought that they can be used as potential biomarkers for further research on subacute ruminal acidosis.

Metabolic profiling of serum and urine in lactating dairy cows affected by subclinical ketosis using proton nuclear magnetic resonance spectroscopy.

Ketosis is associated with high milk yield during lactating or insufficient feed intake in lactating dairy cows. However, few studies have been conducted on the metabolomics of ketosis in Korean lactating dairy cows. The present study aimed to investigate the serum and urine metabolites profiling of lactating dairy cows through proton nuclear magnetic resonance (1H-NMR) spectroscopy and comparing those between healthy (CON) and subclinical ketosis (SCK) groups. Six lactating dairy cows were categorized into CON and SCK groups. All experimental Holstein cows were fed total mixed ration. Serum and urine samples were collected from the jugular vein of the neck and by hand sweeping the perineum, respectively. The metabolites in the serum and urine were determined using 1H-NMR spectroscopy. Identification and quantification of metabolites was performed by Chenomx NMR Suite 8.4 software. Metabolites statistical analysis was performed by Metaboanalyst version 5.0 program. In the serum, the acetoacetate level was significantly (p < 0.05) higher in the SCK group than in the CON group, and whereas acetate, galactose and pyruvate levels tended to be higher. CON group had significantly (p < 0.05) higher levels of 5-aminolevulinate and betaine. Indole-3-acetate, theophylline, p-cresol, 3-hydroxymandelate, gentisate, N-acetylglucosamine, N-nitrosodimethylamine, xanthine and pyridoxine levels were significantly (p < 0.05) higher in the urine of the SCK group than that in the CON group, which had higher levels of homogentisate, ribose, gluconate, ethylene glycol, maltose, 3-methyl-2-oxovalerate and glycocholate. Some significantly (p < 0.05) different metabolites in the serum and urine were associated with ketosis diseases, inflammation, energy balance and body weight. This study will be contributed useful a future ketosis metabolomics studies in Korea.

Metabolic Profiling of Rumen Fluid and Milk in Lactating Dairy Cattle Influenced by Subclinical Ketosis Using Proton Nuclear Magnetic Resonance Spectroscopy.

Ketosis metabolic research on lactating dairy cattle has been conducted worldwide; however, there have been very few Korean studies. Biofluids from lactating dairy cattle are necessary to study ketosis metabolic diseases. Six Holstein cows were divided into two groups (healthy (CON) and subclinical ketosis diagnosed (SCK)). Rumen fluid and milk samples were collected using a stomach tube and a pipeline milking system, respectively. Metabolites were determined using proton nuclear magnetic resonance (NMR) spectroscopy and they were identified and quantified using the Chenomx NMR Suite 8.4 software and Metaboanalyst 5.0. In the rumen fluid of the SCK group, butyrate, sucrose, 3-hydroxybutyrate, maltose, and valerate levels were significantly higher than in the CON group, which showed higher levels of N,N-dimethylformamide, acetate, glucose, and propionate were significantly higher. Milk from the SCK group showed higher levels of maleate, 3-hydroxybutyrate, acetoacetate, galactonate, and 3-hydroxykynurenine than that from the CON group, which showed higher levels of galactitol, 1,3-dihydroxyacetone, γ-glutamylphenylalanine, 5-aminolevulinate, acetate, and methylamine. Some metabolites are associated with ketosis diseases and the quality of rumen fluid and milk. This report will serve as a future reference guide for ketosis metabolomics studies in Korea.

Dynamic changes in blood immune cell composition and function in Holstein and Jersey steers in response to heat stress.

Heat stress has detrimental effects on livestock via diverse immune and physiological changes; heat-stressed animals are rendered susceptible to diverse diseases. However, there is relatively little information available regarding the altered immune responses of domestic animals in heat stress environments, particularly in cattle steers. This study aimed to determine the changes in the immune responses of Holstein and Jersey steers under heat stress. We assessed blood immune cells and their functions in the steers of two breeds under normal and heat stress conditions and found that immune cell proportions and functions were altered in response to different environmental conditions. Heat stress notably reduced the proportions of CD21+MHCII+ B cell populations in both breeds. We also observed breed-specific differences. Under heat stress, in Holstein steers, the expression of myeloperoxidase was reduced in the polymorphonuclear cells, whereas heat stress reduced the WC1+ γδ T cell populations in Jersey steers. Breed-specific changes were also detected based on gene expression. In response to heat stress, the expression of IL-10 and IL-17A increased in Holstein steers alone, whereas that of IL-6 increased in Jersey steers. Moreover, the mRNA expression pattern of heat shock protein genes such as Hsp70 and Hsp90 was significantly increased in only Holstein steers. Collectively, these results indicate that altered blood immunological profiles may provide a potential explanation for the enhanced susceptibility of heat-stressed steers to disease. The findings of this study provide important information that will contribute to developing new strategies to alleviate the detrimental effects of heat stress on steers.

Changes in Blood Metabolites and Immune Cells in Holstein and Jersey Dairy Cows by Heat Stress.

Owing to increasing global temperatures, heat stress is a major problem affecting dairy cows, and abnormal metabolic responses during heat stress likely influence dairy cow immunity. However, the mechanism of this crosstalk between metabolism and immunity during heat stress remains unclear. We used two representative dairy cow breeds, Holstein and Jersey, with distinct heat-resistance characteristics. To understand metabolic and immune responses to seasonal changes, normal environmental and high-heat environmental conditions, we assessed blood metabolites and immune cell populations. In biochemistry analysis from sera, we found that variety blood metabolites were decreased in both Holstein and Jersey cows by heat stress. We assessed changes in immune cell populations in peripheral blood mononuclear cells (PBMCs) using flow cytometry. There were breed-specific differences in immune-cell population changes. Heat stress only increased the proportion of B cells (CD4-CD21+) and heat stress tended to decrease the proportion of monocytes (CD11b+CD172a+) in Holstein cows. Our findings expand the understanding of the common and specific changes in metabolism and immune response of two dairy cow breeds under heat stress conditions.

Diet Transition from High-Forage to High-Concentrate Alters Rumen Bacterial Community Composition, Epithelial Transcriptomes and Ruminal Fermentation Parameters in Dairy Cows.

Effects of changing diet on rumen fermentation parameters, bacterial community composition, and transcriptome profiles were determined in three rumen-cannulated Holstein Friesian cows using a 3 × 4 cross-over design. Treatments include HF-1 (first high-forage diet), HC-1 (first high-concentrate diet), HC-2 (succeeding high-concentrate diet), and HF-2 (second high-forage diet as a recovery period). Animal diets contained Klein grass and concentrate at ratios of 8:2, 2:8, 2:8, and 8:2 (two weeks each), respectively. Ammonia-nitrogen and individual and total volatile fatty acid concentrations were increased significantly during HC-1 and HC-2. Rumen species richness significantly increased for HF-1 and HF-2. Bacteroidetes were dominant for all treatments, while phylum Firmicutes significantly increased during the HC period. Prevotella, Erysipelothrix, and Galbibacter significantly differed between HF and HC diet periods. Ruminococcus abundance was lower during HF feeding and tended to increase during successive HC feeding periods. Prevotellaruminicola was the predominant species for all diets. The RNA sequence analysis revealed the keratin gene as differentially expressed during the HF diet, while carbonic-anhydrase I and S100 calcium-binding protein were expressed in the HC diet. Most of these genes were highly expressed for HC-1 and HC-2. These results suggested that ruminal bacterial community composition, transcriptome profile, and rumen fermentation characteristics were altered by the diet transitions in dairy cows.

Dynamic Changes in Fecal Microbial Communities of Neonatal Dairy Calves by Aging and Diarrhea.

Microbiota plays a critical role in the overall growth performance and health status of dairy cows, especially during their early life. Several studies have reported that fecal microbiome of neonatal calves is shifted by various factors such as diarrhea, antibiotic treatment, or environmental changes. Despite the importance of gut microbiome, a lack of knowledge regarding the composition and functions of microbiota impedes the development of new strategies for improving growth performance and disease resistance during the neonatal calf period. In this study, we utilized next-generation sequencing to monitor the time-dependent dynamics of the gut microbiota of dairy calves before weaning (1-8 weeks of age) and further investigated the microbiome changes caused by diarrhea. Metagenomic analysis revealed that continuous changes, including increasing gut microbiome diversity, occurred from 1 to 5 weeks of age. However, the composition and diversity of the fecal microbiome did not change after 6 weeks of age. The most prominent changes in the fecal microbiome composition caused by aging at family level were a decreased abundance of Bacteroidaceae and Enterobacteriaceae and an increased abundance of Prevotellaceae. Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis indicated that the abundance of microbial genes associated with various metabolic pathways changed with aging. All calves with diarrhea symptoms showed drastic microbiome changes and about a week later returned to the microbiome of pre-diarrheal stage regardless of age. At phylum level, abundance of Bacteroidetes was decreased (p = 0.09) and that of Proteobacteria increased (p = 0.07) during diarrhea. PICRUSt analysis indicated that microbial metabolism-related genes, such as starch and sucrose metabolism, sphingolipid metabolism, alanine aspartate, and glutamate metabolism were significantly altered in diarrheal calves. Together, these results highlight the important implications of gut microbiota in gut metabolism and health status of neonatal dairy calves.

Metabolomics comparison of serum and urine in dairy cattle using proton nuclear magnetic resonance spectroscopy.

OBJECTIVE: The aim of the study was to conduct metabolic profiling of dairy cattle serum and urine using proton nuclear magnetic resonance (1H-NMR) spectroscopy and to compare the results obtained with those of other dairy cattle herds worldwide so as to provide a basic dataset to facilitate research on metabolites in serum and urine. METHODS: Six dairy cattle were used in this study; all animals were fed the same diet, which was composed of total mixed ration; the fed amounts were based on voluntary intake. Blood from the jugular neck vein of each steer was collected at the same time using a separate serum tube. Urine samples were collected by hand sweeping the perineum. The metabolites were determined by 1H-NMR spectroscopy, and the obtained data were statistically analyzed by performing principal component analysis, partial least squares-discriminant analysis, variable importance in projection scores, and metabolic pathway data using Metaboanalyst 4.0. RESULTS: The total number of metabolites in the serum and urine was measured to be 115 and 193, respectively, of which 47 and 81, respectively were quantified. Lactate (classified as an organic acid) and urea (classified as an aliphatic acylic compound) exhibited the highest concentrations in serum and urine, respectively. Some metabolites that have been associated with diseases such as ketosis, bovine respiratory disease, and metritis, and metabolites associated with heat stress were also found in the serum and urine samples. CONCLUSION: The metabolites measured in the serum and urine could potentially be used to detect diseases and heat stress in dairy cattle. The results could also be useful for metabolomic research on the serum and urine of ruminants in Korea.

Effects of Essential Fatty Acid Supplementation on in vitro Fermentation Indices, Greenhouse Gas, Microbes, and Fatty Acid Profiles in the Rumen.

This study estimated the effect of essential fatty acid (FA) supplementation on fermentation indices, greenhouse gases, microbes, and FA profiles in the rumen. The treatments used pure FAs consisting of C18:2n-6 FA (LA), C18:3n-3 FA (LNA), or a mixture of these FAs at 1:1 ratio (Combo). In vitro rumen incubation was performed in 50 mL glass serum bottles containing 2 mg of pure FAs, 15 mL of rumen buffer (rumen fluid+anaerobe culture medium = 1:2), and 150 mg of synthetic diet (411 g cellulose, 411 g starch, and 178 g casein/kg dry matter) at 39°C for 8 h with five replications and three blanks. In rumen fermentation indices, LA exhibited highest (P < 0.05) ammonia-N and total gas volume after 8 h of incubation. Furthermore, LA presented lower (P < 0.05) pH with higher (P < 0.05) total volatile fatty acid (P = 0.034) than Combo, while LNA was not different compared with those in the other treatments. Additionally, Combo produced highest (P < 0.05) CO2 with lowest (P < 0.05) CH4. In the early hours of incubation, LA improved (P < 0.005) Fibrobacter succinogenes and Ruminococcus flavefaciens, while LNA improved (P < 0.005) Ruminococcus albus. After 8 h of incubation, LNA had lower (P < 0.05) methanogenic archaea than LA and Combo but had higher (P < 0.05) rumen ciliates than LA. R. albus was higher (P < 0.05) in LA than in LNA and Combo. It was observed that the rate of biohydrogenation of n-6 and n-3 FAs was comparatively lowest (P < 0.05) in Combo, characterized by higher C18:2n-6 and/or C18:3n-3 FA and polyunsaturated FA (PUFA) concentrations with lower (P < 0.05) concentrations of C18:0 and saturated FA and the ratio of saturated FAs to PUFAs. Therefore, this study concluded that dietary C18:2n-6 could improve populations of fibrolytic bacteria and rumen fermentation indices, but dietary mixture of pure C18:2n-6 and C18:3n-3 is recommended because it is effective in reducing enteric methane emissions and resisting biohydrogenation in the rumen with less effect on rumen microbes.

Exploration of metabolite profiles in the biofluids of dairy cows by proton nuclear magnetic resonance analysis.

Studies that screen for metabolites produced in ruminants are actively underway. We aimed to evaluate the metabolic profiles of five biofluids (ruminal fluid, serum, milk, urine, and feces) in dairy cow by using proton nuclear magnetic resonance (1H-NMR) and provide a list of metabolites in each biofluid for the benefit of future research. We analyzed the metabolites in five biofluids from lactating cows using proton nuclear magnetic resonance imaging; 96, 73, 88, 118, and 128 metabolites were identified in the five biofluids, respectively. In addition, 8, 6, 9, and 17 metabolites were unique to ruminal fluid, serum, milk, and urine, respectively. The metabolites present at high concentrations were: acetate, propionate, and butyrate in ruminal fluid; lactate, glucose, and acetate in serum; and lactose, guanidoacetate, and glucitol in milk. In addition, the following metabolites were present at high concentrations: hippurate, urea, and trimethylamine N-oxide in urine and acetate, propionate, and butyrate in feces. The score plots of the principal component analysis did not show clear distinctions among the five biofluid samples. The purpose of this study was to verify the ability of our metabolomics approaches to identify metabolites in the biofluids of dairy cows.

Metabolomics comparison of rumen fluid and milk in dairy cattle using proton nuclear magnetic resonance spectroscopy.

OBJECTIVE: The metabolites that constitute the rumen fluid and milk in dairy cattle were analyzed using proton nuclear magnetic resonance (1H-NMR) spectroscopy and compared with the results obtain for other dairy cattle herds worldwide. The aim was to provide basic dataset for facilitating research on metabolites in rumen fluid and milk. METHODS: Six dairy cattle were used in this study. Rumen fluid was collected using a stomach tube, and milk was collected using a pipeline milking system. The metabolites were determined by 1H-NMR spectroscopy, and the obtained data were statistically analyzed by principal component analysis, partial least squares discriminant analysis, variable importance in projection scores, and metabolic pathway data using Metaboanalyst 4.0. RESULTS: The total numbers of metabolites in rumen fluid and milk were measured to be 186 and 184, and quantified as 72 and 109, respectively. Organic acid and carbohydrate metabolites exhibited the highest concentrations in rumen fluid and milk, respectively. Some metabolites that have been associated with metabolic diseases (acidosis and ketosis) in cows were identified in rumen fluid, and metabolites associated with ketosis, somatic cell production, and coagulation properties were identified in milk. CONCLUSION: The metabolites measured in rumen fluid and milk could potentially be used to detect metabolic diseases and evaluate milk quality. The results could also be useful for metabolomic research on the biofluids of ruminants in Korea, while facilitating their metabolic research.

Common and Differential Dynamics of the Function of Peripheral Blood Mononuclear Cells between Holstein and Jersey Cows in Heat-Stress Environment.

Heat stress has been reported to affect the immunity of dairy cows. However, the mechanisms through which this occurs are not fully understood. Two breeds of dairy cow, Holstein and Jersey, have distinct characteristics, including productivity, heat resistance, and disease in high-temperature environments. The objective of this study is to understand the dynamics of the immune response of two breeds of dairy cow to environmental change. Ribonucleic acid sequencing (RNA-seq) results were analyzed to characterize the gene expression change of peripheral blood mononuclear cells (PBMCs) in Holstein and Jersey cows between moderate temperature-humidity index (THI) and high THI environmental conditions. Many of the differentially expressed genes (DEGs) identified are associated with critical immunological functions, particularly phagocytosis, chemokines, and cytokine response. Among the DEGs, CXCL3 and IL1A were the top down-regulated genes in both breeds of dairy cow, and many DEGs were related to antimicrobial immunity. Functional analysis revealed that cytokine and chemokine response-associated pathways in both Holstein and Jersey PBMCs were the most important pathways affected by the THI environmental condition. However, there were also breed-specific genes and pathways that altered according to THI environmental condition. Collectively, there were both common and breed-specific altered genes and pathways in Holstein and Jersey cows. The findings of this study expand our understanding of the dynamics of immunity in different breeds of dairy cow between moderate THI and high THI environmental conditions.

New challenges for efficient usage of Sargassum fusiforme for ruminant production.

Sargassum fusiforme, which is a type of brown algae, can provide fiber and minerals to ruminant diets. In this study, dried S. fusiforme was tested in vitro at four different doses 1, 3, 5, and 10% of the total ration for its effect on ruminal fermentation characteristics, and gas profiles when incubated for 72 h. At a level of 1 and 10%, S. fusiforme supplementation augmented total volatile fatty acid (VFA) concentrations compared to that with 0% supplementation. In addition, total gas, methane, and carbon dioxide emissions significantly decreased at 3 and 24 h of incubation at this dose. An in situ trial was performed for 72 h with S. fusiforme to evaluate it as a potential feed ingredient by comparing its degradation parameters with timothy hay (Phleum pretense). 1H nuclear magnetic resonance spectroscopy profiling was used to identify and quantify metabolites of S. fusiforme. Mannitol, guanidoacetate and ethylene glycol were largely accumulated in S. fusiforme. Moreover, nutritious minerals for feed ingredients were present in S. fusiforme. Whereas a high concentration of arsenic was found in S. fusiforme, it was within the allowable limit for ruminants. Our results suggest that S. fusiforme could represent an alternative, renewable feed ingredient for ruminant diets, with nutritional, as well as environmental, benefits.

Hydrolyzed Yeast Supplementation in Calf Starter Promotes Innate Immune Responses in Holstein Calves under Weaning Stress Condition.

Weaned calves are susceptible to infectious diseases because of the stress and malnutrition that occurs during weaning. Therefore, the dairy industry requires effective feed additives to ameliorate stress responses and promote immunity. This study aimed to investigate the effects of hydrolyzed yeast (HY) supplementation on the growth performance, immune and stress parameters, and health status of calves after weaning. Eighteen Holstein calves were randomly assigned to two groups, either receiving a control calf starter or 0.2% HY calf starter from one week of age. All calves were weaned at six weeks of age as a stress challenge. The HY-fed calves had a significantly-higher body weight gain during the post-weaning period (kg/week) compared to the control. Cortisol levels at three days post-weaning (DPW) were significantly lower in the HY group than the control group. Calves fed HY had significantly-higher serum levels of tumor necrosis factor-α and interleukin-1ß at one DPW. The HY-fed calves also had higher concentrations of the acute-phase proteins, haptoglobin, serum amyloid A, and transferrin at one DPW. In addition, the diarrhea severity in HY-fed calves was milder after weaning compared to the control group. Our results indicate that HY supplementation reduces stress responses and may promote innate immunity in newly-weaned calves.

Differential Dynamics of the Ruminal Microbiome of Jersey Cows in a Heat Stress Environment.

The microbial community within the rumen can be changed and shaped by heat stress. Accumulating data have suggested that different breeds of dairy cows have differential heat stress resistance; however, the underlying mechanism by which nonanimal factors contribute to heat stress are yet to be understood. This study is designed to determine changes in the rumen microbiome of Holstein and Jersey cows to normal and heat stress conditions. Under heat stress conditions, Holstein cows had a significantly higher respiration rate than Jersey cows. Heat stress increased the rectal temperature of Holstein but not Jersey cows. In the Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, Jersey cows had a significantly higher proportion of genes associated with energy metabolism in the normal condition than that with other treatments. Linear discriminant analysis effect size (LEfSe) results identified six taxa as distinguishing taxa between normal and heat stress conditions in Holstein cows; in Jersey cows, 29 such taxa were identified. Changes in the rumen bacterial taxa were more sensitive to heat stress in Jersey cows than in Holstein cows, suggesting that the rumen mechanism is different in both breeds in adapting to heat stress. Collectively, distinct changes in rumen bacterial taxa and functional gene abundance in Jersey cows may be associated with better adaptation ability to heat stress.

Enhancing Butyrate Production, Ruminal Fermentation and Microbial Population through Supplementation with Clostridium saccharobutylicum.

Butyrate is known to play a significant role in energy metabolism and regulating genomic activities that influence rumen nutrition utilization and function. Thus, this study investigated the effects of an isolated butyrate-producing bacteria, Clostridium saccharobutylicum, in rumen butyrate production, fermentation parameters and microbial population in Holstein-Friesian cow. An isolated butyrate-producing bacterium from the ruminal fluid of a Holstein-Friesian cow was identified and characterized as Clostridium saccharobutylicum RNAL841125 using 16S rRNA gene sequencing and phylogenetic analyses. The bacterium was evaluated on its effects as supplement on in vitro rumen fermentation and microbial population. Supplementation with 106 CFU/ml Clostridium saccharobutylicum increased (p < 0.05) microbial crude protein, butyrate and total volatile fatty acids concentration but had no significant effect on NH3-N at 24 h incubation. Butyrate and total VFA concentrations were higher (p < 0.05) in supplementation with 106 CFU/ml Clostridium saccharobutylicum compared with control, with no differences observed for total gas production, NH3-N and propionate concentration. However, as the inclusion rate (CFU/ml) of C. saccharobutylicum was increased, reduction of rumen fermentation values was observed. Furthermore, butyrate-producing bacteria and Fibrobacter succinogenes population in the rumen increased in response with supplementation of C. saccharobutylicum, while no differences in the population in total bacteria, protozoa and fungi were observed among treatments. Overall, our study suggests that supplementation with 106 CFU/ml C. saccharobutylicum has the potential to improve ruminal fermentation through increased concentrations of butyrate and total volatile fatty acid, and enhanced population of butyrate-producing bacteria and cellulolytic bacteria F. succinogenes.

Effect of sodium stearoyl-2-lactylate supplementation on lactation performance, blood-biochemical profile, and economic efficacy of mid-lactation Holstein cows.

OBJECTIVE: This study was done to evaluate the effect of sodium stearoyl-2-lactylate (SSL) supplementation in a total mixed ration (TMR) on the lactation performance, blood parameters, and economic efficacy of mid-lactation Holstein cows. METHODS: Twenty-four cows (body weight 647±11.7 kg) were randomly divided into 4 treatment groups, with six cows per group. The dietary treatments were as follows: basal diet (CON); CON+17.5 g of top dressed SSL (treatment [TRT] 0.05); CON+35 g of SSL (TRT 0.1); and CON+70 g of SSL (TRT 0.2) per 35 kg TMR. RESULTS: The highest level of SSL supplementation (TRT 0.2) significantly improved milk yield during the second period compared to the TRT 0.05 group (5 to 8 wks; 33.28 vs 31.09 kg/d), during the third period compared to both the CON and TRT 0.05 groups (p<0.05) (9 to 13 wks; 32.59 vs 30.64 and 30.01 kg/d) and during the overall experimental period compared to both the CON and TRT 0.05 groups (p<0.05) (1 to 13 wks; 33.43 vs 32.06 and 31.40 kg/d), respectively. No negative effects on hematological or biochemical parameters were observed due to SSL supplementation. Considering both the milk fat and protein content, the total milk price was set at 1,073.60 (TRT 0.05), 1,085.60 (TRT 0.1), 1,086.10 (TRT 0.2), and 1,064.20 (CON) won/L, with consequent total milk profits of -1.7%, 5.4%, and 3.5% for the TRT 0.05, TRT 0.1, and TRT 0.2 diet, respectively, compared to those in the CON diet. CONCLUSION: The milk sales revenue related to SSL supplementation of the TRT 0.1 diet was increased by up to 5.4% compared to the milk sales revenue of the CON diet. Therefore, 0.1% SSL supplementation might be effective and profitable during the mid-lactation period of cows, without producing adverse effects.

Effect of optimal sodium stearoyl-2-lactylate supplementation on growth performance and blood and carcass characteristics in Hanwoo steers during the early fattening period.

OBJECTIVE: This study was conducted to evaluate the effect of different levels of total digestible nutrients (TDN) and sodium stearoyl-2-lactylate (SSL) supplementation on growth performance and blood and carcass characteristics in Hanwoo steers during the early fattening period. METHODS: Sixty Hanwoo steers (average body weight, 333±36.4 kg) were randomly allotted to 3 treatments, with twenty steers per treatment, and ten steers per pen with a size of 80 m2. Dietary treatments were as follows: CON, basal diet; treatment (TRT) 0.5, 0.5% down-spec of TDN with 0.1% SSL; TRT 1.0, 1.0% down-spec of TDN with 0.1% SSL. RESULTS: The results demonstrated that average daily gain and feed efficiency increased with TRT 0.5 (0.85 kg and 11.68) vs CON (0.82 kg and 11.27) or TRT 1.0 (0.78 kg and 10.74), indicating that 0.1% SSL supplementation in the feed of early fattening steers may result in a saving of 0.5% TDN. No significant differences were observed amongst all treatments (p> 0.05) for blood metabolite concentration and blood corpuscle values, which were all within the normally accepted range for healthy steers. CONCLUSION: Our study suggests that a TDN 0.5% down spec with 0.1% SSL supplemented feed may be effective and profitable for the early fattening period of Hanwoo steers without causing adverse effects.

Effect of Rhodophyta extracts on in vitro ruminal fermentation characteristics, methanogenesis and microbial populations.

OBJECTIVE: Due to the threat of global warming, the livestock industry is increasingly interested in exploring how feed additives may reduce anthropogenic greenhouse gas emissions, especially from ruminants. This study investigated the effect of Rhodophyta supplemented bovine diets on in vitro rumen fermentation and rumen microbial diversity. METHODS: Cannulated Holstein cows were used as rumen fluid donors. Rumen fluid:buffer (1:2; 15 mL) solution was incubated for up to 72 h in six treatments: a control (timothy hay only), along with substrates containing 5% extracts from five Rhodophyta species (Grateloupia lanceolata [Okamura] Kawaguchi, Hypnea japonica Tanaka, Pterocladia capillacea [Gmelin] Bornet, Chondria crassicaulis Harvey, or Gelidium amansii [Lam.] Lamouroux). RESULTS: Compared with control, Rhodophyta extracts increased cumulative gas production after 24 and 72 h (p = 0.0297 and p = 0.0047). The extracts reduced methane emission at 12 and 24 h (p<0.05). In particular, real-time polymerase chain reaction analysis indicated that at 24 h, ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens decreased at 24 h (p = 0.0002, p<0.0001, and p<0.0001), while Fibrobacter succinogenes (F. succinogenes) increased (p = 0.0004). Additionally, Rhodophyta extracts improved acetate concentration at 12 and 24 h (p = 0.0766 and p = 0.0132), as well as acetate/propionate (A/P) ratio at 6 and 12 h (p = 0.0106 and p = 0.0278). CONCLUSION: Rhodophyta extracts are a viable additive that can improve ruminant growth performance (higher total gas production, lower A/P ratio) and methane abatement (less ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens and more F. succinogenes.