Organic acids as a substitute for monensin in diets for beef cattle

Alternatives to conventional antibiotics for the prevention and treatment of commonly occurring diseases in feedlot cattle

Antibiotic-resistant bacteria are a problem in human medicine. The development of antibiotic resistance in bacteria in feedlot cattle could have negative effects on their health and welfare and there is a theoretical possibility of transmission of antibiotic-resistant bacteria from food animals to humans. Alternatives to conventional antibiotics in feedlot health management could reduce the selective pressure for the development of antibiotic resistance. This review assesses the evidence supporting potential alternatives to conventional antibiotics in the prevention and treatment of diseases in feedlot cattle, including nitric oxide, plant extracts, supplemental yeast or yeast products, bacterial probiotics, organic acids, bacteriophages and non-specific immunostimulants. Further research is warranted with lactate utilising bacteria, the organic acid malate, bacteriophages and the non-specific immunostimulants β-1,3 glucan and those based on pox viruses. However, none of the alternatives to conventional antibiotics investigated in this review have sufficient supporting evidence to date to justify their use with feedlot cattle. Frequently, statistically weak results and studies without negative controls are cited as support for similar studies. The health and welfare of feedlot cattle are dependent on the use of products that have robust supporting data to ensure efficacy and to avoid adverse outcomes.

Disodium Fumarate Alleviates Endoplasmic Reticulum Stress, Mitochondrial Damage, and Oxidative Stress Induced by the High-Concentrate Diet in the Mammary Gland Tissue of Hu Sheep

The long-term feeding of the high-concentrate diet (HC) reduced rumen pH and induced subacute rumen acidosis (SARA), leading to mammary gland tissue damage among ruminants. Disodium fumarate enhanced rumen bufferation and alleviated a decrease in rumen pH induced by the HC diet. Therefore, the purpose of this study was to investigate whether disodium fumarate could alleviate endoplasmic reticulum (ER) stress, mitochondrial damage, and oxidative stress induced by the high-concentrate diet in the mammary gland tissue of Hu sheep. In this study, 18 Hu sheep in mid-lactation were randomly divided into three groups: one fed with a low-concentrate diet (LC) diet, one fed with a HC diet, and one fed with a HC diet with disodium fumarate (AHC). Each sheep was given an additional 10 g of disodium fumarate/day. The experiment lasted for eight weeks. After the experiment, rumen fluid, blood, and mammary gland tissue were collected. The results show that, compared with the LC diet, the HC diet could reduce rumen pH, and the pH below 5.6 was more than 3 h, and the LPS content of blood and rumen fluid in HC the diet was significantly higher than in the LC diet. This indicates that the HC diet induced SARA in Hu sheep. However, the supplementation of disodium fumarate in the HC diet increased the rumen pH and decreased the content of LPS in blood and rumen fluid. Compared with the LC diet, the HC diet increased Ca²⁺ content in mammary gland tissue. However, the AHC diet decreased Ca²⁺ content. The HC diet induced ER stress in mammary gland tissue by increasing the mRNA and protein expressions of GRP78, CHOP, PERK, ATF6, and IRE1α. The HC diet also activated the IP3R-VDAC1-MCU channel and lead to mitochondrial damage by inhibiting mitochondrial fusion and promoting mitochondrial division, while disodium fumarate could alleviate these changes. In addition, disodium fumarate alleviated oxidative stress induced by the HC diet by activating Nrf2 signaling and reducing ROS production in mammary gland tissue. In conclusion, the supplementation of disodium fumarate at a daily dose of 10 g/sheep enhanced rumen bufferation by maintaining the ruminal pH above 6 and reduced LPS concentration in ruminal fluid and blood. This reaction avoided the negative effect observed by non-supplemented sheep that were fed with a high-concentrate diet involving endoplasmic reticulum stress, oxidative stress, and mitochondrial damage in the mammary gland tissue of Hu sheep.

Synergistic Effects of 3-Nitrooxypropanol with Fumarate in the Regulation of Propionate Formation and Methanogenesis in Dairy Cows In Vitro

3-Nitrooxypropanol (3-NOP) is effective at reducing ruminal methane emissions in ruminants. But it also causes a drastic increase in hydrogen accumulation, resulting in feed energy waste. Fumarate is a key precursor for propionate formation and plays an important role in rumen hydrogen metabolism. Therefore, this study examined the effects of 3-NOP combined with fumarate on volatile fatty acids, methanogenesis, and microbial community structures in dairy cows in vitro. The in vitro culture experiment was performed using a 2-by-2 factorial design, two 3-NOP levels (0 or 2 mg/g dry matter [DM]) and two fumarate levels (0 or 100 mg/g DM), including 3 runs with 4 treatments, 4 replicates, and 4 blanks containing only the inoculum. Rumen fluid was collected from three lactating Holstein cows with permanent ruminal fistulas. The combination of 3-NOP and fumarate reduced methane emissions by 11.48% without affecting dry matter degradability. The propionate concentration increased and the acetate/propionate ratio decreased significantly. In terms of bacteria, the combination of 3-NOP and fumarate reduced the abundances of Ruminococcus and Lachnospiraceae_NK3A20_group and increased the abundances of Prevotella and Succiniclasticum. For archaea, the combination of 3-NOP and fumarate significantly increased the abundances of Methanobrevibacter_sp._AbM4, while the abundance of operational taxonomic unit 581 (OTU581) (belonging to an uncultured_rumen_methanogen_g__Methanobrevibacter strain) was significantly decreased. These results indicated that the combination of 3-NOP and fumarate could alleviate the accumulation of hydrogen and enhance the inhibition of methanogenesis compared with 3-NOP only in dairy cows. IMPORTANCE The global problem of climate change and the greenhouse effect has become increasingly severe, and the abatement of greenhouse gases has received great attention from the international community. Methane produced by ruminants during digestion not only aggravates the greenhouse effect but also causes a waste of feed energy. As a methane inhibitor, 3-nitrooxypropanol can effectively reduce methane emissions from ruminants. However, when it inhibits methane emissions, the emission of hydrogen increases sharply, resulting in the waste of feed resources. Fumarate is a propionic acid precursor that can promote the metabolism of hydrogen to propionic acid in animals. Therefore, we studied the effects of the combined addition of 3-nitrooxypropanol and fumarate on methanogenesis, rumen fermentation, and rumen flora. It is of great significance to inhibit methane emission from ruminants and slow down the greenhouse effect.

Role of herbal products in animal production - An updated review

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are used for health and medical functions since ancient times. Plants and their extracts are also well-known phytobiotics or phytogenics that are widely used in animal traditional and alternative medicine. In recent years the use of herbal/plant medicine is increased in livestock production due to the side effects of modern drugs, the high input costs, toxic residues in food, microbial resistance and due to the development of organic livestock production systems. Plants are used as health promoters and also for the treatment of diseases.

AIM OF THE STUDY

This review aims to provide information on various plants used in animal health care, production and reproduction in various forms.

METHODS

We carefully searched the scientific literature for data related to traditional scientific use of herbal products in animal production. This review summarized published literature collected from library, the online databases, and various scientific search engines including PubMed, Elsevier, Google Scholar, Science Direct, Scopus, and Research gate. The Plant List (www.theplantlist.org) databases were used to provide the scientific names, subspecies of plants.

RESULTS

Various herbs play important role in production and reproduction of animal. Herbs acts as feed additives, growth promoters, immune boosters, improves reproduction in animals and also helps in reduction of methane and ammonia emission. Secondary metabolites like Tanins, saponin, flavonoids and essential oils are the most used for rumen manipulation and have great potential in poultry and pig nutrition.

CONCLUSION

The traditional knowledge may play important role, hence documentation and preservation is a must before it is lost forever. Medicinal herbs are a potential source as therapeutics and nutritive aids and have a significant role in health system all over the world for both humans and animals.

The effects of feeding benzoic acid and/or live active yeast (Saccharomyces cerevisiae) on beef cattle performance, feeding behavior, and carcass characteristics

Fifty-nine Angus-cross finishing steers were used to evaluate benzoic acid, active dry yeast (Saccharomyces cerevisiae), or a combination of benzoic acid and active dry yeast when supplemented in a high-grain finishing diet on live animal performance, feeding behavior, and carcass characteristics. Steers were fed a high-grain diet for the final 106 d of finishing. Treatments were as follows: no additional supplementation (CON), 0.5% benzoic acid (ACD), 3 g per head per day active dry S. cerevisiae (YST), or both 0.5% benzoic acid and 3 g/head per day S. cerevisiae (AY). Steers were weighed every 14 d, and ultrasound was performed for rib and rump fat thickness at the beginning (day 1), middle (day 57), and end (day 99) of the experiment. Insert feeding stations were used to collect individual feeding behavior data and DMI daily throughout. Blood samples were collected on days 21 and 22 and days 99-101 to assess plane of nutrition and metabolism. Ruminal fluid samples were collected by oral gavage 4 wk prior to slaughter. Carcass characteristics were examined at a federally inspected slaughter facility. Data were analyzed using PROC GLIMMIX of SAS with initial body weight (BW) as a covariate. Benzoic acid supplementation increased (P = 0.002) overall dry matter intake (DMI) compared to YST and CON steers, which may be due to a faster eating rate (P ≤ 0.008). Animal performance parameters (BW, average daily gain, feed conversion, and ultrasound fat depth) were not different (P ≥ 0.11) among treatment groups. Aspartate aminotransferase concentration was greatest (P ≤ 0.01) for YST steers, which may have been reflected in numerically greater liver abscesses. Carcass traits did not differ (P ≥ 0.33) among treatment groups. Ruminal pH was greater (P = 0.006) for ACD steers than AY steers (pH of 6.16 vs. 5.66, respectively), which indicated that there may be an interactive effect between benzoic acid and active dry yeast. To summarize, steers fed a high-grain finishing diet supplemented with benzoic acid, active dry yeast, or both benzoic acid and active dry yeast had similar growth performance and carcass characteristics compared to those without supplementation. However, the addition of benzoic acid alone increased DMI, variation in DMI, eating rate, and ruminal pH. Future studies are warranted to further investigate the impacts of benzoic acid on the ruminal environment of feedlot cattle.

Metabolic Benefit of Bulls Being Fed Moringa Leaves Twigs and Branches as a Major Concentrate Ingredient

The study was conducted to investigate nutrient metabolism and semen quality of bulls fed with moringa (Moringa oleifera) leaves, twigs, and branches as a major concentrate ingredient. Twenty-one Red Chittagong bulls of about 204 (±50) kg initial live weight (LW) were randomly divided into three equal LW groups. They were fed maize silage as a basal feedstuff for 65 days with the supplementation of concentrate mixtures at 1% of LW, consisting of either 0, 25, or 50% moringa mash on a fresh basis. Moringa mash was a sun-dried ground preparation of leaves, twigs, and branches of moringa. The results indicated that different levels of moringa in concentrate mixtures (0, 25, and 50%) did not change daily DM intake, digestibility, and LW gain of bulls (p > 0.05). However, increasing dietary moringa (up to 203 g/kg DM) significantly decreased production cost of methane (CH4) (methane emission [kg/kg gain] = 1.6422—[0.0059 × moringa intake, g/kg DM], n = 12, R2 = 0.384, P = 0.032) in a similar metabolizable energy intake level (0.21 ± 0.01 MJ/kg LW). Also, higher dietary moringa significantly reduced urinary nitrogen loss (urinary nitrogen [% digested nitrogen] = 43.0 – 0.069 × moringa intake [g/kg DM]; R2 = 0.3712, P = 0.034). Thus, increasing moringa by 1 g/kg DM decreased CH4 emission by 6 g/kg gain and absorbed nitrogen loss by 0.069 %. Also, progressive motility of sperm increased significantly (33.0, 51.0, and 60.1%, respectively; p = 0.03) in bulls fed with concentrate mixtures containing moringa at 0, 25, or 50%. It may be concluded that feeding moringa mash at 203 g/kg DM may decrease energy loss as methane and urinary nitrogen loss without impacting the production of beef cattle. Feeding moringa mash to beef cattle may abate dietary energy and nitrogen loss and consequently decrease the environmental pollution.

Effects of organic acids in total mixed ration and feeding frequency on productive performance of dairy cows

This study aimed to evaluate the effects of organic acid (OA; Mold-Zap, Alltech, Nicholasville, KY) inclusion in the total mixed ration (TMR) and feeding frequency of TMR for lactating dairy cows on intake, total-tract apparent digestibility, sorting index, feeding behavior, ruminal fermentation, milk yield and composition, nitrogen balance, and serum metabolites. Twenty-four lactating Holstein cows, 4 with rumen cannulas, with (mean ± standard error) 247 ± 22.2 d in milk, 672 ± 14.6 kg of body weight, and 31.1 ± 1.09 kg of milk yield at the beginning of the experiment were used. The cows were distributed in a balanced and contemporary 4 × 4 Latin square experimental design and randomly assigned in a 2 × 2 factorial arrangement to evaluate OA [0 (OA-) or 0.5 (OA+) L of Mold-Zap/tonne of TMR on a natural matter basis] and feeding frequency of TMR offered once a day (1×) or twice a day (2×). Each experimental period lasted 21 d, with 14 d for acclimation and 7 d for data collection. The treatments were tested for TMR, in which its temperature was recorded every 2 h through a 24-h period in each experimental period. Organic acid-treated TMR showed a lower temperature during the 24-h period compared with nontreated TMR. The OA and feeding frequency had no effect on intake and total-tract apparent digestibility of dry matter and nutrients, aside from a tendency to increase neutral detergent fiber digestibility in cows fed 2×. Also, cows fed 1× tended to select more particles between 19 and 8 mm and refused particles smaller than 4 mm, whereas cows fed OA tended to select more particles smaller than 4 mm. Cows fed OA had greater milk yield and milk protein and lactose yields, but tended to have higher 3.5% fat-corrected milk yield. Neither treatment influenced ruminal and serum variables nor milk fat yield and milk production efficiency. Cows fed OA spent less time idling and tended to have lower rumination time, and tended to have higher time spent drinking water and eating, whereas animals fed 1× spent more time drinking water. Under the conditions of this experiment, we conclude that it was possible to reduce the feeding frequency of TMR, without negative effects on dairy cow performance. However, the use of OA resulted in higher milk yield and mitigated TMR temperature rise regardless of feeding frequency. The effect of external factors such as collective stimulation of intake and stage of lactation on feeding frequency effect must be surveyed in further research.

Effects of essential oils and(or) benzoic acid in beef finishing cattle diets on the fatty acid profile and shelf life stability of ribeye steaks and ground beef

The effects of feeding essential oils and(or) benzoic acid to finishing steers on fatty acid profile and oxidative stability (color and lipid oxidation) of beef longissimus thoracis steaks and ground beef was determined in this study. Beef was procured from crossbred beef steers (n = 63) fed one of five dietary treatments: (1) control (no antibiotics fed); (2) monensin/tylosin (monensin supplemented at 33 mg/kg [DM basis]; tylosin supplemented at 11 mg/kg [DM basis]); (3) essential oils (supplemented at 1.0 g/steer/day); (4) benzoic acid (supplemented at 0.5% [DM basis]); and (5) combination (essential oils supplemented at 1.0 g/steer/day and benzoic acid supplemented at 0.5% [DM basis]). Although no improvements in shelf life stability were observed, feeding finishing cattle essential oils and(or) benzoic acid did not have detrimental impacts on beef color stability and lipid oxidation over a simulated retail display period.

Co-abundance analysis reveals hidden players associated with high methane yield phenotype in sheep rumen microbiome

Rumen microbial environment hosts a variety of microorganisms that interact with each other to carry out the feed digestion and generation of several by-products especially methane, which plays an essential role in global warming as a greenhouse gas. However, due to its multi-factorial nature, the exact cause of methane production in the rumen has not yet been fully determined. The current study is an attempt to use system modeling to analyze the relationship between interacting components of rumen microbiome and its role in methane production. Metagenomic data of sheep rumen, with equal numbers of high methane yield (HMY) and low methane yield (LMY) samples, were used. As a well-known approach for the systematic comparative study of complex traits, the co-abundance networks were constructed in both operational taxonomic unit (OTU) and gene levels. A gene-catalog of 1,444 different rumen microbial strains was developed as a reference to measure gene abundances. The results from both types of co-abundance networks showed that methanogens, which are the main ruminal source for methanogenesis, need other microbial species to accomplish the task of methane production through producing the main precursor molecules like H₂ and acetate for methanogenesis pathway as their byproducts. KEGG Orthology(KO) analysis of the current study shows that the metabolism and growth rate of methanogens will be increased due to the higher rate of the metabolism and carbohydrate/fiber digestion pathways in the hidden elements. This finding proposes that any ruminant methane yield alteration strategy should consider complex interactions of rumen microbiome components as one tightly integrated unit rather than several separate parts.

Effect of Palm Kernel Meal and Malic Acid on Rumen Characteristics of Growing Naemi Lambs Fed Total Mixed Ration

This study was conducted to investigate the effect of malic acid and 20% palm kernel meal (PKM) on ruminal characteristics. A total of 32 growing lambs were randomly distributed into control (barley and alfalfa ha), total mixed ration (T1), TMR + 20% PKM (T2), TMR + PKC 20% + 4 mL/day malic acids (T3). Lambs were fed these diets ad libitum for 84 days. The results showed that propionic acid in the rumen fluid increased significantly (p < 0.05) in T1 and T3. Lactic acid concentration of rumen fluid increased significantly (p < 0.05) in T2 while the pH increased significantly. The coloration of rumen and reticulum was improved in T3. In addition, most of the histomorphological features were higher in T3 and T2. We concluded that the addition of malic acid supplementation to lambs fed PKC caused a significant improvement in the rumen pH and decreased lactic acid concentration in growing Naemi lambs.

Advanced estimation and mitigation strategies: a cumulative approach to enteric methane abatement from ruminants

Methane, one of the important greenhouse gas, has a higher global warming potential than that of carbon dioxide. Agriculture, especially livestock, is considered as the biggest sector in producing anthropogenic methane. Among livestock, ruminants are the highest emitters of enteric methane. Methanogenesis, a continuous process in the rumen, carried out by archaea either with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to methane or with methylotrophic pathway, which the substrate for methanogenesis is methyl groups. For accurate estimation of methane from ruminants, three methods have been successfully used in various experiments under different environmental conditions such as respiration chamber, sulfur hexafluoride tracer technique, and the automated head-chamber or GreenFeed system. Methane production and emission from ruminants are increasing day by day with an increase of ruminants which help to meet up the nutrient demands of the increasing human population throughout the world. Several mitigation strategies have been taken separately for methane abatement from ruminant productions such as animal intervention, diet selection, dietary feed additives, probiotics, defaunation, supplementation of fats, oils, organic acids, plant secondary metabolites, etc. However, sustainable mitigation strategies are not established yet. A cumulative approach of accurate enteric methane measurement and existing mitigation strategies with more focusing on the biological reduction of methane emission by direct-fed microbials could be the sustainable methane mitigation approaches.

Effects of microbial feed additives on feed utilization and growth performance in growing Barki lambs fed diet based on peanut hay

The effects of supplementing diet of growing lambs with microbial feed additive mixture (direct-fed microbial; DFM) based on Saccharomyces cerevisiae, lactic acid bacteria and exogenous enzymes on feed intake, nutrient digestibility, nitrogen (N) utilization, ruminal fermentation, blood chemistry and growth performance were studied. The study was a completely randomized design with 12 growing Barki lambs divided into two groups of six lambs per treatment. Lambs were offered a control diet of peanut hay and concentrates (1:1 dry matter (DM) basis) or the control diet supplemented with DFM at 0.5 g/day (Bactozyme treatment) for 16 weeks. There was no effect on feed efficiency but Bactozyme lambs had increased (p = 0.009) feed intake, average daily gain (p = 0.042) and final body weight (p = 0.047). Bactozyme treatment had greater neutral detergent fiber (p = 0.020) and acid detergent fiber (p = 0.034) digestibility compared with the control treatment. Metabolism experiment showed that the feed additive mixture increased (p<0.05) N intake and N retention. Bactozyme treatment had greater blood total protein (p = 0.027), and globulin (p = 0.025) concentrations compared with the control treatment. It is concluded that supplementing growing Barki lambs with DFM at 0.5 g daily enhanced final body weight gain and fiber digestion without affecting feed efficiency.

Organic additives used in beef cattle feedlot: Effects on metabolic parameters and animal performance

Organic additives are recently being used in animal diets owing to their ability to control metabolic issues and result in better animal performance. Specifically, the organic additive Fator P^® presents an additional advantage that is to cause a lesser greenhouse gas emission. This study evaluated whether Fator P^® intake changes ruminal parameters or animal performance of beef cattle. Evaluations were carried out in a feedlot experiment divided into growing (46 days; two diets [control mix-CM and standard mix-SM] and finishing (lasted 83 days; four diets: CM, SM, Fator P^® + virginiamycin, and Fator P^® alone [FP]) trials. Animal performance study involved 48 animals allocated to 12 collective pens in completely randomized experimental design. Ruminal parameters were evaluated in separate metabolism study developed carried out using individual pen with four steers. During growing trial, FP diet resulted in higher (p < 0.05) dry matter intake (DMI) and ruminating time. In the finishing trial, diets containing Fator P^® resulted in higher DMI than obtained with CM. Most of the ruminal parameters did not differ (p > 0.05) among dietary treatments. Therefore, Fator P^® represents a viable and safe strategy for supplementation to beef cattle finished using high-concentrate diet in feedlot systems.

Dietary manipulation: a sustainable way to mitigate methane emissions from ruminants

Methane emission from the enteric fermentation of ruminant livestock is a main source of greenhouse gas (GHG) emission and a major concern for global warming. Methane emission is also associated with dietary energy lose; hence, reduce feed efficiency. Due to the negative environmental impacts, methane mitigation has come forward in last few decades. To date numerous efforts were made in order to reduce methane emission from ruminants. No table mitigation approaches are rumen manipulation, alteration of rumen fermentation, modification of rumen microbial biodiversity by different means and rarely by animal manipulations. However, a comprehensive exploration for a sustainable methane mitigation approach is still lacking. Dietary modification is directly linked to changes in the rumen fermentation pattern and types of end products. Studies showed that changing fermentation pattern is one of the most effective ways of methane abatement. Desirable dietary changes provide two fold benefits i.e. improve production and reduce GHG emissions. Therefore, the aim of this review is to discuss biology of methane emission from ruminants and its mitigation through dietary manipulation.

Feeding corn grain steeped in citric acid modulates rumen fermentation and inflammatory responses in dairy goats

Cereal grains treated with organic acids were proved to increase ruminal resistant starch and can relieve the risk of ruminal acidosis. However, previous study mainly focussed on acid-treated barley, the effects of organic acid-treated corn is still unknown. The objectives of this study were to evaluate whether feeding ground corn steeped in citric acid (CA) would affect ruminal pH and fermentation patterns, milk production and innate immunity responses in dairy goats. Eight ruminally cannulated Saanen dairy goats were used in a crossover designed experiment. Each experimental period was 21 day long including 14 days for adaption to new diet and 7 days for sampling and data collection. The goats were fed high-grain diet contained 30% hay and 70% corn-based concentrate. The corn was steeped either in water (control) or in 0.5% (wt/vol) CA solution for 48 h. Goats fed CA diet showed improved ruminal pH status with greater mean and minimum ruminal pH, and shorter (P&lt;0.05) duration of ruminal pH&lt;5.6 and less area of ruminal pH&lt;5.6, 5.8 and 6.0. Concentration of total volatile fatty acid and molar proportion of propionate were less but the molar proportion of acetate was greater (P&lt;0.05) in goats fed the CA diet than the control diet. Concentration of ruminal lipopolysaccharide (LPS) was lower (P&lt;0.05) and that of lactic acid also tended (P&lt;0.10) to be lower in goats fed CA than the control. Although dry matter intake, actual milk yield, yield and content of milk protein and lactose were not affected, the milk fat content and 4% fat-corrected milk tended (P&lt;0.10) to be greater in goats fed CA diet. For the inflammatory responses, peripheral LPS did not differ, whereas the concentration of LPS binding protein and serum amyloid A tended (P&lt;0.10) to be less in goats fed CA diet. Similarly, goats fed CA diet had less (P&lt;0.05) concentration of haptoglobin and tumour necrosis factor. These results indicated that feeding ground corn treated with CA effectively improved ruminal pH status, thus alleviated the risk of ruminal acidosis, reduced inflammatory response, and tend to improve milk yield and milk fat test.

Effects of addition of malic or citric acids on fermentation quality and chemical characteristics of alfalfa silage

We studied the effects on alfalfa preservation and chemical composition of the addition of different levels of malic acid and citric acid at ensiling as well as the utilization efficiency of these 2 organic acids after fermentation. Alfalfa was harvested at early bloom stage. After wilting to a dry matter content of approximately 40%, the alfalfa was chopped into 1- to 2-cm pieces for ensiling. Four levels (0, 0.1, 0.5, and 1% of fresh weight) of malic acid or citric acid were applied to chopped alfalfa at ensiling with 4 replicates for each treatment, and the treated alfalfa forages were ensiled for 60 d in vacuum-sealed polyethylene bags (dimensions: 200 mm × 300 mm) packed with 200 to 230 g of fresh alfalfa per mini silo and an initial density of 0.534 g/cm³. The application of malic or citric acids at ensiling for 60 d led to lower silage pH than was observed in the control silage (0% of malic or citric acids). Application of the 2 organic acids led to higher lactic acid concentration in alfalfa silage than in the control silage except with the application rate of 1% of fresh weight. Silages treated with both organic acids had lower nonprotein nitrogen concentrations than the control silages, and the nonprotein nitrogen concentrations in ensiled forages decreased with the increase in malic or citric acid application rates. The application of the 2 organic acid additives led to lower saturated fatty acid proportions and higher polyunsaturated fatty acid proportions in ensiled alfalfa than in the control silage. The amount of malic and citric acids degraded during ensiling of alfalfa was 1.45 and 0.63 g, respectively. At the application rate of 0.5% of fresh weight, residues of malic acid and citric acid in alfalfa silage were 11.1 and 13.6 g/kg of dry matter. These results indicate that including malic or citric acids at the ensiling of alfalfa effectively improved silage fermentation quality, limited proteolysis, improved fatty acid composition of the ensiled forage, and could provide animals with additional feed additives proven to promote animal performance. However, when the application rate of both organic acids reached 1%, the concentration of lactic acid in silages decreased notably. Additionally, 0.5 and 1% application rates also increased the yeast count in ensiled alfalfa.

Effects of Disodium Fumarate on In Vitro Rumen Fermentation, The Production of Lipopolysaccharide and Biogenic Amines, and The Rumen Bacterial Community

The effect of disodium fumarate (DF) on the ruminal fermentation profiles, the accumulation of lipopolysaccharide (LPS) and bioamines, and the composition of the ruminal bacterial community was investigated by in vitro rumen fermentation. The addition of DF increased the total gas production; the concentrations of propionate, valerate, total volatile fatty acids, and ammonia-nitrogen; and the rumen pH after a 24 h fermentation. By contrast, DF addition decreased the ratio of acetate to propionate and the concentrations of lactate, lipopolysaccharide, methylamine, tryptamine, putrescine, histamine, and tyramine (P < 0.05). Principal coordinates analysis and molecular variance analysis showed that DF altered the ruminal bacterial community (P < 0.05). At the phylum level, DF decreased the proportion of Proteobacteria, and increased the proportions of Spirochaetae and Elusimicrobia (P < 0.05). At the genus level, DF decreased the percentage of Ruminobacter, while increasing the percentage of Succinivibrio and Treponema (P < 0.05). Overall, the results indicate that DF modified rumen fermentation and mitigated the production of several toxic compounds. Thus, DF has great potential for preventing subacute rumen acidosis in dairy cows and for improving the health of ruminants.

Influence of fumaric acid on ruminal parameters and organ weights of growing bulls fed with grass or maize silage

The influence of the potential methane reducer, fumaric acid (FA), on ruminal parameters, the rumen wall and organ weights was investigated in a long-term study with growing bulls. In all, 20 bulls were fed with maize or grass silage as roughage, and with concentrate with or without 300 g FA per animal and day during the whole fattening period. After slaughtering, the organs were weighed and blood serum was analysed for glucose, β-hydroxybutyric acid (BHB) and non-esterified fatty acid concentration. The ruminal fluid was analysed for short-chain fatty acids, ammonia-N and the microbial community via single strand conformation polymorphism analysis. The rumen wall was examined histopathologically and results were graded as 'no visible lesions', 'few inflammatory infiltrates', 'some inflammatory infiltrates' or 'several inflammatory infiltrates'. In addition, the dimensions of the rumen villi were measured. The FA supplementation decreased the serum BHB concentration and the butyric acid concentration in the ruminal fluid. The microbial community in the ruminal fluid was not influenced by FA. An interaction between FA and silage type was observed for the inflammation centres counted in the villous area of rumen papillae. This interaction was also observed in the length and surface of the rumen villi. Rumen villi results show that the influence of FA depends on the roughage used in the diet.

Feeding a High Concentration Diet Induces Unhealthy Alterations in the Composition and Metabolism of Ruminal Microbiota and Host Response in a Goat Model

There is limited knowledge about the impact of long-term feeding a high-concentrate (HC) diet on rumen microbiota, metabolome, and host cell functions. In this study, a combination of mass spectrometry-based metabolomics techniques, 454 pyrosequencing of 16S rDNA genes, and RT-PCR was applied to evaluate the changes of ruminal microbiota composition, ruminal metabolites, and related genes expression in rumen epithelial cells of lactating goats received either a 35% concentrate diet or a 65% concentrate diet for 4 or 19 weeks, respectively. Results show that feeding a HC diet reduced the microbiota diversity and led to the disorders of metabolism in the rumen. The concentrations of lactate, phosphorus, NH3-N and endotoxin Lipopolysaccharide in ruminal fluids, and plasma histamine, lactate and urine N (UN) were increased significantly in goats fed with a HC diet. A significant increase of genes expression related to volatile fatty acids transport, cell apoptosis, and inflammatory responses were also observed in goats fed with a HC diet. Correlation analysis revealed some potential relationships between bacteria abundance and metabolites concentrations. Our findings indicate that a HC diet can induce ruminal microbiota dysbiosis and metabolic disorders, thus increasing risks to host health and potential harm to the environment.

Effect of disodium/calcium malate or supplementation on growth performance, carcass quality, ruminal fermentation products, and blood metabolites of heifers

The aim of this study was to assess the effects of malate salts and culture on growth performance, carcass quality, ruminal fermentation products, and blood metabolites in heifers raised under southern Europe practical farm conditions. A total of 108 Charolaise cross heifers (214 ± 27.3 kg BW and 6.4 ± 1.1 mo of age) were housed in 18 pens of 6 animals each and used in a 114-d feedlot study. There was a totally randomized experimental design, and 6 pens were assigned to each of the following experimental diets: a control (no supplementation), the control plus 4 g of disodium/calcium malate mixture per kilogram of concentrate (2.12 g malate/kg), and the control plus 0.15 g of CBS 493.94 per kilogram of concentrate (1.5 × 10 cfu/kg). The control diet consisted of wheat-barley-based pelleted concentrate (32% starch, DM basis) and full-length barley straw. Concentrate and straw were fed separately ad libitum (5% orts) in an 88:12 ratio. On Days 0, 56, and 114, ruminal fluid and blood samples were obtained from each heifer between 2 and 2.5 h after the morning feeding by ruminocentesis and tail venipuncture, respectively. Body weight, concentrate ADFI, and G:F were recorded at 28, 56, 84, and 114 d. At slaughter, hot carcass weight and yield and carcass classification were determined in 2 representative heifers per pen (12 animals per dietary treatment). Supplementation with malate salts or did not affect concentrate ADFI ( = 0.98), ADG ( = 0.74), or G:F ( = 0.50) at any time during the experiment. At slaughter, there were no differences in carcass weight ( = 0.86), classification ( = 0.18), or carcass yield ( = 0.84) among experimental groups. Also, there were no differences treatments on ruminal pH ( = 0.24), ruminal fermentation products ( = 0.69, = 0.88, and = 0.93 for total VFA, NH-N, and lactate, respectively), and blood metabolites ( = 0.96, = 0.82, and = 0.15 for glucose, urea N, and lactate, respectively). In conclusion, under the feeding and management conditions of this study, diet supplementation with malate salts or did not have any significant effects on growth performance, carcass quality, ruminal fermentation products, and blood metabolites.

Dietary linseed oil with or without malate increases conjugated linoleic acid and oleic acid in milk fat and and gene expression in mammary gland and milk somatic cells of lactating goats

Supplementary dietary plant oils have the potential to alter milk fatty acid composition in ruminants as a result of changes in the amount and kind of fatty acid precursors. We hypothesized that linseed oil in combination with malate (a key propionate precursor in the rumen) would increase ∆9 unsaturated fatty acids and specific gene expression in somatic cells and mammary glands of lactating goats. Twelve lactating goats were used in a 3 × 3 Latin square design. Treatments included the basal diet (CON), the CON plus 4% linseed oil (LO), and the CON plus 4% linseed oil and 2% -malate (LOM). Relative to CON, the LO and LOM supplements increased the daily intake of palmitic (16:0), stearic (18:0), oleic (18:1-9), linoleic (18:2-6), α-linolenic (18:3-3), and γ-linolenic acids (18:2-6); α-linolenic acid intake was increased over 9-fold, from 6.77 to over 51 g/d ( < 0.02). The LO and LOM supplements increased daily milk yield, milk fat yield, and milk fat percentage ( < 0.05). The LOM supplement also increased milk lactose percentage and daily yield ( = 0.03). Both the LO and LOM supplements increased plasma glucose and total cholesterol and decreased plasma β-hydroxbutyrate concentrations ( = 0.03). The LO and LOM supplements increased concentrations of stearic acid; -vaccenic acid (TVA; 18:1-11); -9, -11 CLA; -10 -12 CLA; and α-linolenic acid in rumen fluid and increased the concentrations of oleic acid; TVA; -9, -11 CLA; -10, -12 CLA; and α-linolenic acid in plasma lipids and milk fat ( < 0.05). Conversely, the LO and LOM supplements decreased short- and medium-chain SFA, including lauric (12:0), myristic (14:0), and palmitic acids, in plasma and milk fat ( < 0.05). Relative mRNA levels for and () gene expression were increased in somatic cells and mammary gland tissue by LO and LOM ( < 0.05). We conclude that the higher intake and ruminal production of stearic acid promoted SCD gene expression in somatic cells and mammary tissue. Furthermore, milk somatic cells are a suitable substitute for documenting treatment effects of dietary oils on gene expression in goat mammary tissue.

Effects of feeding a spray-dried multivalent polyclonal antibody preparation on feedlot performance, feeding behavior, carcass characteristics, rumenitis, and blood gas profile of Brangus and Nellore yearling bulls

The objective of this study was to evaluate the effects of replacing monensin (MON) with a spray-dried multivalent polyclonal antibody preparation (PAP) against several ruminal microorganisms on feedlot performance, carcass characteristics, feeding behavior, blood gas profile, and the rumenitis incidence of Brangus and Nellore yearling bulls. The study was designed as a completely randomized design with a 2 × 2 factorial arrangement, replicated 6 times (4 bulls per pen and a total of 24 pens), in which bulls ( = 48) of each biotype were fed diets containing either MON fed at 300 mg/d or PAP fed at 3 g/d. No significant feed additive main effects were observed for ADG ( = 0.27), G:F ( = 0.28), HCW ( = 0.99), or dressing percentage ( = 0.80). However, bulls receiving PAP had greater DMI ( = 0.02) and larger ( = 0.02) final LM area as well as greater ( < 0.01) blood concentrations of bicarbonate and base excess in the extracellular fluid than bulls receiving MON. Brangus bulls had greater ( < 0.01) ADG and DMI expressed in kilograms, final BW, heavier HCW, and larger initial and final LM area than Nellore bulls. However, Nellore bulls had greater daily DMI fluctuation ( < 0.01), expressed as a percentage, and greater incidence of rumenitis ( = 0.05) than Brangus bulls. In addition, Brangus bulls had greater ( < 0.01) DMI per meal and also presented lower ( < 0.01) DM and NDF rumination rates when compared with Nellore bulls. Significant interactions ( < 0.05) between biotype and feed additive were observed for SFA, unsaturated fatty acids (UFA), MUFA, and PUFA concentrations in adipose tissues. When Nellore bulls were fed PAP, fat had greater ( < 0.05) SFA and PUFA contents but less ( < 0.01) UFA and MUFA than Nellore bulls receiving MON. For Brangus bulls, MON led to greater ( < 0.05) SFA and PUFA and less ( < 0.05) UFA and MUFA than Brangus bulls fed PAP. Feeding a spray-dried PAP led to similar feedlot performance compared with that when feeding MON. Spray-dried PAP might provide a new technology alternative to ionophores.

Effect of supplementation of rice bran and fumarate alone or in combination on in vitro rumen fermentation, methanogenesis and methanogens

This study investigated the effect of fumarate (FUM) and rice bran (RB), alone and together, on in vitro rumen fermentation, methanogenesis and methanogens. In vitro incubation was performed with six media that were either unsupplemented (control) or supplemented with 10% RB, 5 mmol/L FUM, 10% RB + 5 mmol/L FUM, 10 mmol/L FUM, or 10% RB + 10 mmol/L FUM. Methane (CH4 ) production, dry matter digestibility, CH4 per digested dry matter, total short-chain fatty acid (SCFA) production, proportion of SCFA, acetate : proprionate ratio, production of NH3 -N, and population density of rumen microbes were determined. Supplementation with 10% RB + 10 mmol/L FUM yielded a 36% decrease in CH4 production compared to the control. Supplementation of FUM, in the presence or absence of RB, provided increases in total SCFA production and propionate proportion up to 61% and 31%, respectively. Total bacteria, methanogens and protozoa populations were significantly (P < 0.05) decreased with the 10% RB + 10 mmol/L FUM supplementation. The effect of anti-methanogenesis of FUM was enhanced by the addition of RB. Notably, the CH4 production attenuation was achieved by 10% RB + 10 mmol/L FUM without reduction of digestibility or of ruminal fermentation.

Effects of dietary linseed oil and propionate precursors on ruminal microbial community, composition, and diversity in Yanbian yellow cattle

The rumen microbial ecosystem is a complex system where rumen fermentation processes involve interactions among microorganisms. There are important relationships between diet and the ruminal bacterial composition. Thus, we investigated the ruminal fermentation characteristics and compared ruminal bacterial communities using tag amplicon pyrosequencing analysis in Yanbian yellow steers, which were fed linseed oil (LO) and propionate precursors. We used eight ruminally cannulated Yanbian yellow steers (510 ± 5.8 kg) in a replicated 4 × 4 Latin square design with four dietary treatments. Steers were fed a basal diet that comprised 80% concentrate and 20% rice straw (DM basis, CON). The CON diet was supplemented with LO at 4%. The LO diet was also supplemented with 2% dl-malate or 2% fumarate as ruminal precursors of propionate. Dietary supplementation with LO and propionate precursors increased ruminal pH, total volatile fatty acid concentrations, and the molar proportion of propionate. The most abundant bacterial operational taxonomic units in the rumen were related to dietary treatments. Bacteroidetes dominated the ruminal bacterial community and the genus Prevotella was highly represented when steers were fed LO plus propionate precursors. However, with the CON and LO diet plus malate or fumarate, Firmicutes was the most abundant phylum and the genus Ruminococcus was predominant. In summary, supplementing the diets of ruminants with a moderate level of LO plus propionate precursors modified the ruminal fermentation pattern. The most positive responses to LO and propionate precursors supplementation were in the phyla Bacteriodetes and Firmicutes, and in the genus Ruminococcus and Prevotella. Thus, diets containing LO plus malate or fumarate have significant effects on the composition of the rumen microbial community.

Ruminal acidosis in feedlot: from aetiology to prevention

Acute ruminal acidosis is a metabolic status defined by decreased blood pH and bicarbonate, caused by overproduction of ruminal D-lactate. It will appear when animals ingest excessive amount of nonstructural carbohydrates with low neutral detergent fiber. Animals will show ruminal hypotony/atony with hydrorumen and a typical parakeratosis-rumenitis liver abscess complex, associated with a plethora of systemic manifestations such as diarrhea and dehydration, liver abscesses, infections of the lung, the heart, and/or the kidney, and laminitis, as well as neurologic symptoms due to both cerebrocortical necrosis and the direct effect of D-lactate on neurons. In feedlots, warning signs include decrease in chewing activity, weight, and dry matter intake and increase in laminitis and diarrhea prevalence. The prognosis is quite variable. Treatment will be based on the control of systemic acidosis and dehydration. Prevention is the most important tool and will require normalization of ruminal pH and microbiota. Appropriate feeding strategies are essential and involve changing the dietary composition to increase neutral detergent fiber content and greater particle size and length. Appropriate grain processing can control the fermentation rate while additives such as prebiotics or probiotics can help to stabilize the ruminal environment. Immunization against producers of D-lactate is being explored.

Effects of Defaunation on Fermentation Characteristics and Methane Production by Rumen Microbes In vitro When Incubated with Starchy Feed Sources

An in vitro experiment was conducted to examine the effects of defaunation (removal of protozoa) on ruminal fermentation characteristics, CH₄ production and degradation by rumen microbes when incubated with cereal grains (corn, wheat and rye). Sodium lauryl sulfate as a defaunation reagent was added into the culture solution at a concentration of 0.000375 g/ml, and incubated anaerobically for up to 12 h at 39°C. Following defaunation, live protozoa in the culture solution were rarely observed by microscopic examination. A difference in pH was found among grains regardless of defaunation at all incubation times (p<0.01 to 0.001). Defaunation significantly decreased pH at 12 h (p<0.05) when rumen fluid was incubated with grains. Ammonia-N concentration was increased by defaunation for all grains at 6 h (p<0.05) and 12 h (p<0.05) incubation times. Total VFA concentration was increased by defaunation at 6 h (p<0.05) and 12 h (p<0.01) for all grains. Meanwhile, defaunation decreased acetate and butyrate proportions at 6 h (p<0.05, p<0.01) and 12 h (p<0.01, p<0.001), but increased the propionate proportion at 3 h, 6 h and 12 h incubation (p<0.01 to 0.001) for all grains. Defaunation increased in vitro effective degradability of DM (p<0.05). Production of total gas and CO₂ was decreased by defaunation for all grains at 1 h (p<0.05, p<0.05) and then increased at 6 h (p<0.05, p<0.05) and 12 h (p<0.05, p<0.05). CH₄ production was higher from faunation than from defaunation at all incubation times (p<0.05).

Peculiarities of enhancing resistant starch in ruminants using chemical methods: opportunities and challenges

High-producing ruminants are fed high amounts of cereal grains, at the expense of dietary fiber, to meet their high energy demands. Grains consist mainly of starch, which is easily degraded in the rumen by microbial glycosidases, providing energy for rapid growth of rumen microbes and short-chain fatty acids (SCFA) as the main energy source for the host. Yet, low dietary fiber contents and the rapid accumulation of SCFA lead to rumen disorders in cattle. The chemical processing of grains has become increasingly important to confer their starch resistances against rumen microbial glycosidases, hence generating ruminally resistant starch (RRS). In ruminants, unlike monogastric species, the strategy of enhancing resistant starch is useful, not only in lowering the amount of carbohydrate substrates available for digestion in the upper gut sections, but also in enhancing the net hepatic glucose supply, which can be utilized by the host more efficiently than the hepatic gluconeogenesis of SCFA. The use of chemical methods to enhance the RRS of grains and the feeding of RRS face challenges in the practice; therefore, the present article attempts to summarize the most important achievements in the chemical processing methods used to generate RRS, and review advantages and challenges of feeding RRS to ruminants.

Rumen microbial response in production of CLA and methane to safflower oil in association with fish oil or/and fumarate

Supplementation effect of fish oil and/or fumarate on production of conjugated linoleic acid (CLA) and methane by rumen microbes was examined when incubated with safflower oil. One hundred and twenty milligrams of safflower oil (SO), safflower oil with 24 mg fish oil (SOFO), safflower oil with 24 mmol/L fumarate (SOFA), or safflower oil with 24 mg fish oil and 24 mmol/L fumarate (SOFOFA) were added to the 90 mL culture solution. The culture solution was also made without any supplements (control). The SOFA and SOFOFA increased pH and propionate (C3) compared to other treatments from 3 h incubation time. An accumulated amount of total methane (CH(4) ) for 12 h incubation was decreased by all the supplements compared to control. The concentrations of c9,t11CLA for all the incubation times were increased in the treatments of SOFO, SOFA and SOFOFA compared to SO. The highest concentration of c9,t11CLA was observed from SOFOFA among all the treatments at all incubation times. Overall data indicate that supplementation of combined fumarate and/or fish oil when incubated with safflower oil could depress CH(4) generation and increase production of C(3) and CLA under the condition of current in vitro study.