Comparison of the in vitro efficiency of supplementary bee propolis extracts of different origin in enhancing the ruminal degradability of organic matter and mitigating the formation of methane

Synergistic effect of potential alpha-amylase inhibitors from Egyptian propolis with acarbose using in silico and in vitro combination analysis

BACKGROUND

Type 2 Diabetes mellitus (DM) is an affliction impacting the quality of life of millions of people worldwide. An approach used in the management of Type 2 DM involves the use of the carbohydrate-hydrolyzing enzyme inhibitor, acarbose. Although acarbose has long been the go-to drug in this key approach, it has become apparent that its side effects negatively impact patient adherence and subsequently, therapeutic outcomes. Similar to acarbose in its mechanism of action, bee propolis, a unique natural adhesive biomass consisting of biologically active metabolites, has been found to have antidiabetic potential through its inhibition of α-amylase. To minimize the need for ultimately novel agents while simultaneously aiming to decrease the side effects of acarbose and enhance its efficacy, combination drug therapy has become a promising pharmacotherapeutic strategy and a focal point of this study.

METHODS

Computer-aided molecular docking and molecular dynamics (MD) simulations accompanied by in vitro testing were used to mine novel, pharmacologically active chemical entities from Egyptian propolis to combat Type 2 DM. Glide docking was utilized for a structure-based virtual screening of the largest in-house library of Egyptian propolis metabolites gathered from literature, in addition to GC-MS analysis of the propolis sample under investigation. Thereafter, combination analysis by means of fixed-ratio combinations of acarbose with propolis and the top chosen propolis-derived phytoligand was implemented.

RESULTS

Aucubin, identified for the first time in propolis worldwide and kaempferol were the most promising virtual hits. Subsequent in vitro α-amylase inhibitory assay demonstrated the ability of these hits to significantly inhibit the enzyme in a dose-dependent manner with an IC50 of 2.37 ± 0.02 mM and 4.84 ± 0.14 mM, respectively. The binary combination of acarbose with each of propolis and kaempferol displayed maximal synergy at lower effect levels. Molecular docking and MD simulations revealed a cooperative binding mode between kaempferol and acarbose within the active site.

CONCLUSION

The suggested strategy seems imperative to ensure a steady supply of new therapeutic entities sourced from Egyptian propolis to regress the development of DM. Further pharmacological in vivo investigations are required to confirm the potent antidiabetic potential of the studied combination.

Red propolis extract as a natural ionophore for confined sheep: performance and morphological and histopathological changes

This study aimed to evaluate the effect of increasing levels of red propolis extract (RPE) in the diet of confined sheep on performance and histomorphometric parameters of rumen and intestine and histopathological parameters of liver and kidney. Thirty-five male sheep (17.08 ± 2.36 kg) were used, distributed in a completely randomized design, with five treatments (0, 7, 14, 21, and 28 mL day-1 RPE) and seven replications, submitted to 68 days of experiment. At the end of the experimental period, the animals were euthanized, and samples of rumen, intestine, liver, and kidney were collected to histomorphometry and histopathology analyzes. Higher RPE inclusions (21 and 28 mL day-1) maintained dry matter intake and increased total weight (5.78 x 6.14 and 6.95 kg, respectively) gain up to 20.24%. In the rumen, the inclusion of RPE led to an increase in the thickness of the epithelium and the highest level also increased the thickness of the keratinized portion of this epithelium (21.71 x 32.15 μm). The level of 21 mL day-1 provided larger ruminal papillae (1620.68 x 1641.70 μm) and greater ruminal absorption area (561791.43 x 698288.50 μm2). In intestine 21 and 28 mL-1 of RPE provided greater mucosal thickness (468.54 x 556.20 and 534.64 μm), higher goblet cell index (23.32 x 25.82 and 25.64) and higher hepatic glycogen index (1.47 x 1.64 and 1.62), supporting higher nutrients absortion and glicogenolise and intestinal health, corroborating the weight gain indices. The inclusion of RPE did not cause renal histopathological lesions. Therefore, levels of 21 and 28 mL day-1 of RPE can be used in sheep diets, promoting greater final weight gain, causing positive histomorphological changes in the rumen, intestine and liver, without causing kidney or liver damage.

The effect of propolis extract on milk production and composition, serum biochemistry, and physiological parameters of heat-stressed dairy cows

The aim of this study was to evaluate whether feeding propolis extract (PE) influences nutrient intake, milk production and composition, serum biochemistry, and physiological parameters of heat-stressed dairy cows. For this purpose, we used three primiparous Holstein cows with a lactation period of 94 ± 4 days and with 485 ± 13 kg body weight. The treatments were 0 mL/day, 32 mL/day, and 64 mL/day of PE randomly assigned in a 3x3 Latin square design, repeated over time. The experiment lasted a total of 102 days; each Latin square lasted 51 days divided into three 17-day periods (12 days for adaptation and five days for data collection). The PE supply did not influence (P > 0.05) the cows' intake of dry matter (18.96 kg/d), crude protein (2.83 kg/d), and neutral detergent-insoluble fiber (7.36 kg/d), but there was an increase in feeding time with the 64 ml/day PE supply (P < 0.05). Providing 64 ml/day of PE tended (P = 0.06) to increase milk production by 11.64% and improve gross feed efficiency of cows by 12.04%. The PE supply did not influence milk composition and blood parameters of cows (P > 0.05). Offering 32 mL/day of PE decreased (P < 0.05) the rectal temperature and respiratory rate of cows. We recommend a supply of 64 mL/day of PE for heat-stressed dairy cows.

Management of Enteric Methane Emissions in Ruminants Using Feed Additives: A Review

In ruminants' metabolism, a surplus of hydrogen is removed from the reduction reaction of NAD⁺ (nicotinamide adenine dinucleotide) by the formation of methane by methanogenic bacteria and archaea methanogens. The balance of calculations between VFA (volatile fatty acids), CO₂, and CH₄ indicates that acetate and butyrate play a role in methane production, while the formation of propionate maintains hydrogen and therefore reduces methane production. CH₄ formation in ruminant livestock is not desired because it reduces feed efficiency and contributes to global warming. Therefore, numerous strategies have been investigated to mitigate methane production in ruminants. This review focuses on feed additives which have the capability of reducing methane emissions in ruminants. Due to the environmental importance of methane emissions, such studies are needed to make milk and meat production more sustainable. Additionally, the additives which have no adverse effects on rumen microbial population and where the reduction effects are a result of their hydrogen sink property, are the best reduction methods. Methane inhibitors have shown such a property in most cases. More work is needed to bring methane-reducing agents in ruminant diets to full market maturity, so that farmers can reap feed cost savings and simultaneously achieve environmental benefits.

Ruminal Bacterial Community Successions in Response to Monensin Supplementation in Goats

Simple Summary

Monensin has been successfully used in the ruminants’ diets to manipulate ruminal fermentation and improve feed efficiency, but its use is facing decreased levels of social acceptance due to the potential impacts on public health. Understanding the ruminal bacterial community successions in response to monensin supplementation would help the search for alternatives. We found that the ruminal ecosystem was reshaped through a series of succession processes during the adaption to monensin rather than following a clear dichotomy between Gram-positive and Gram-negative cell types, and the carbohydrate-degrading bacteria presented a higher adaptability. Therefore, a potential alternative for monensin as a rumen modifier could be one with similar patterns of ruminal microbial community successions.

Abstract

Previous studies have demonstrated that the effects of monensin on methanogenesis and ruminal fermentation in ruminants were time-dependent. To elucidate the underlying mechanism, we investigated the ruminal bacterial community successions during the adaptation to monensin supplementation and subsequent withdrawal in goats. The experiment included a baseline period of 20 days followed by a treatment period of 55 days with 32 mg monensin/d and a washout period of 15 days. Monensin supplementation reduced the α diversity and changed the structure of ruminal microflora. The α diversity was gradually restored during adaption, but the structure was still reshaped. The temporal dynamics of 261 treatment- and/or time-associated ruminal bacteria displayed six patterns, with two as monensin-sensitive and four as monensin-resistant. The monensin sensitivity and resistance of microbes do not follow a clear dichotomy between Gram-positive and Gram-negative cell types. Moreover, the temporal dynamic patterns of different bacterial species within the same genus or family also displayed variation. Of note, the relative abundance of the total ruminal cellulolytic bacteria gradually increased following monensin treatment, and that of the total amylolytic bacteria were increased by monensin, independent of the duration. In conclusion, under the pressure of monensin, the ruminal ecosystem was reshaped through a series of succession processes, and the carbohydrate-degrading bacteria presented a higher level of adaptability.

Prosopis juliflora piperidine alkaloid extract levels in diet for sheep change energy and nitrogen metabolism and affect enteric methane yield

BACKGROUND

Ionophore antibiotics improve the efficiency of energy metabolism, which has driven their use as a feed additive in ruminants for decades. Currently, they have not been approved in many countries, generating a challenge for the immediate search for plant extracts with a similar mode of action on rumen metabolism. This study evaluated the effects of enriched Prosopis juliflora (mesquite) piperidine alkaloid extract (MPA) levels as an alternative phytoadditive to sodium monensin (MON) in sheep.

RESULTS

The MPA diet did not differ from MON with regard to nutrient intake. A quadratic effect (P < 0.05) was observed for organic matter and neutral detergent fibre digestibility, with respective maximum point at 25.40 and minimum point at 0.95 mg kg^-1 MPA. The MPA levels linearly decreased (P < 0.05) faecal nitrogen loss. MPA did not differ from MON with regard to nutrient digestibility, and MPA levels increased (P < 0.05) the proportion of digestible energy and metabolizability from dietary gross energy. The MPA levels linearly decreased (P < 0.05) enteric CH₄ production, the yield showing lower (P < 0.05) energy loss as CH₄ than MON.

CONCLUSION

The results show that MPA levels of 17.3 and 27.8 mg kg^-1 are enteric CH₄ inhibitors and enhance energy and protein utilization, indicating a promising alternative to MON for ruminants. © 2022 Society of Chemical Industry.

Ruminal Microbiome Manipulation to Improve Fermentation Efficiency in Ruminants

The rumen is an integrated dynamic microbial ecosystem composed of enormous populations of bacteria, protozoa, fungi, archaea, and bacteriophages. These microbes ferment feed organic matter consumed by ruminants to produce beneficial products such as microbial biomass and short-chain fatty acids, which form the major metabolic fuels for ruminants. The fermentation process also involves inefficient end product formation for both host animals and the environment, such as ammonia, methane, and carbon dioxide production. In typical conditions of ruminal fermentation, microbiota does not produce an optimal mixture of enzymes to maximize plant cell wall degradation or synthesize maximum microbial protein. Well-functioning rumen can be achieved through microbial manipulation by alteration of rumen microbiome composition to enhance specific beneficial fermentation pathways while minimizing or altering inefficient fermentation pathways. Therefore, manipulating ruminal fermentation is useful to improve feed conversion efficiency, animal productivity, and product quality. Understanding rumen microbial diversity and dynamics is crucial to maximize animal production efficiency and mitigate the emission of greenhouse gases from ruminants. This chapter discusses genetic and nongenetic rumen manipulation methods to achieve better rumen microbial fermentation including improvement of fibrolytic activity, inhibition of methanogenesis, prevention of acidosis, and balancing rumen ammonia concentration for optimal microbial protein synthesis.

Modified Nano-Montmorillonite and Monensin Modulate In Vitro Ruminal Fermentation, Nutrient Degradability, and Methanogenesis Differently

Two types of modified nano-montmorillonite (MNM) were developed by ion-exchange reactions using two different surfactants; sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CETAB), to prepare MNM_SDS and MNM_CETAB, respectively. Both MNM types were on the nano-scale and had higher cation-exchange capacity values than NM clay. The MNM_CETAB had the highest zeta potential (-27 mV) compared with the other clays. Effects of MNM types on in vitro ruminal batch culture fermentation, nutrient degradability, and methane (CH₄) emission compared with monensin were evaluated in vitro using a semi-automatic gas production system. The experimental treatments were the control (0 supplementations), monensin (40 mg/kg DM), and NM (5 g NM/kg DM), and two levels of MNM_SDS and MNM_CETAB were supplemented at 0.05 (low) and 0.5 (high) g/kg DM to the control basal feed substrate. Among the experimental treatments, the high dose of both MNM types reduced (p < 0.01) CH₄ production and ammonia concentrations compared with the control, while only MNM_CETAB treatment tended to increase (p = 0.08) the truly degraded organic matter compared with monensin. All MNM treatments increased (p < 0.01) acetate molar proportions compared with monensin. The high MNM_CETAB increased (p < 0.01) the in vitro ruminal batch culture pH compared with the control and monensin. The MNM_CETAB supplemented at 0.5 g/kg DM is the most efficient additive to reduce CH₄ emission with the advantage of enhancing the in vitro nutrient degradability of the experimental feed substrate. These results indicated that MNM could modulate the in vitro ruminal fermentation pattern in a dose- and type-dependent manner.

Can roughage: concentrate ratio affect the action of red propolis extract on sheep metabolism?

The aim of the present study was to evaluate whether the addition of red propolis extract (RPE), in different roughage: concentrate (R:C) ratios, influences the intake, digestibility, ruminal parameters, and serum biochemistry of sheep. We used eight Santa Inês sheep with an average body weight of 29.45 ± 1.58 kg, housed in metabolism cages for 60 days, and distributed in two simultaneous Latin square designs in a 2 × 2 factorial scheme. The factors consisted of two R:C ratios (70:30 and 30:70) with or without the addition of 15 mL/day of RPE. No interactions were found (P > 0.05) between R:C ratios and with or without RPE. Sheep fed 30:70 ratio showed higher (P < 0.05) intake and dry matter (DM) digestibility and non-fibrous carbohydrates and lower (P < 0.05) intake and neutral detergent fiber (NDF) digestibility. The addition of RPE did not influence (P > 0.05) the intake or nutrients digestibility, but the sheep that received RPE had a higher (P < 0.05) ruminal pH and longer (P < 0.05) time of rumination (min/kg DM) compared to the group without propolis. The ruminal ammonia concentration was higher for sheep fed 70:30 ratio, but the concentrations of total protein and albumin did not differ between R:C ratios. The addition of 15 mL of RPE does not influence the intake, digestibility, ingestive behavior, and rumen ammonical nitrogen of sheep. There is no association between the R:C ratio and the addition of 15 mL/day of RPE for sheep.

Inclusion of a blend of copaiba, cashew nut shell and castor oil in the protein-energy supplement for grazing beef cattle improves rumen fermentation, nutrient intake and fibre digestibility

Context Essential oils are secondary plant compounds extracted from plants, with potential for the modulation of rumen fermentation. Aims Two experiments, namely one in vivo and another in vitro, were conducted to analyse the effects of a commercial blend of essential oils (EO; copaiba (Copaifera langsdorffii), cashew nut shell (Anacardium occidentale) and castor oil (Ricinus communis) and monensin as dietary feed additives in protein–energy supplements (PES) provided to grazing beef cattle, on ruminal fermentation, intake, total nutrient digestibility and protein dietary efficiency. Methods In the in vivo experiment, four entire Nellore bulls cannulated in the rumen (374 ± 15.66 kg; mean ± s.d.) were used in a 4 × 4 Latin-square design to evaluate the effects of EO concentration and monensin on voluntary intake, digestibility, and rumen and metabolic characteristics of grazing beef cattle provided with supplementation during the rainy season. Treatments were as follows: control (CON; PES without additives); monensin (MON; PES with inclusion of monensin at 20 mg/kg DM consumed); EO150 (PES with inclusion of EO at 150 mg/kg DM consumed); EO300 (PES with inclusion of EO at 300 mg/kg DM consumed). In the in vitro experiment, the effects EO150, EO300 and EO450, MON and CON on DM and neutral detergent-fibre (NDF) digestibility, and total gas production, were evaluated in four consecutive runs using a gas-production (GP) system. Key results In the in vivo experiment, DM intake, forage DM intake, crude protein intake and NDF intake were similar (P &gt; 0.05) between EO150 and MON, but both were greater than those in EO300 and CON (P &lt; 0.05). A lower EO concentration (EO150) increased (P &lt; 0.05) NDF digestibility and improved nitrogen utilisation efficiency. In the in vitro experiment, the addition of MON and EO150 did not modify (P &gt; 0.05) GP, DM and NDF digestibility compared with the control, but EO300 and EO450 decreased GP at 12 and 24 h and decreased DM and NDF digestibility at 48 h compared with the control, MON and EO150. Conclusions In vivo and in vitro results suggested that EO (copaiba oil, cashew nut shell and castor) at low doses (150 mg/kg DM) has the potential to improve ruminal fermentation in grazing beef cattle receiving supplements, but medium and high doses of EO can have adverse effects. Implications EO blends could be an alternative to MON for grazing beef cattle with access to supplements.

Antibacterial Effect of Peruvian Propolis Collected During Different Seasons on the Growth of Streptococcus Mutans

Introduction:

Propolis is a gummy, resinous substance made by bees from the buds and exudates of plants. The antibacterial activity of propolis has been widely studied and is known to vary according to its geographical origin, the type of surrounding flora, the collecting bee species, the mode of its collection and even the season in which it is collected. Unfortunately, these observations have not been corroborated experimentally.

Aim:

To compare the antibacterial activities of ethanolic extracts of propolis collected in the summer and autumn on the growth of Streptococcus mutans ATCC 25175.

Materials and Methods:

Propolis samples were collected in the summer and autumn and labeled “A” or “B” by an individual who was not directly involved in the study. Then, 5% ethanolic extracts of propolis were prepared for each sample. S. mutans was plated onto brain heart infusion agar plates into which wells were formed, and the plates were divided into four groups to test the antibacterial effectiveness of both the extracts and the positive (0.12% chlorhexidine digluconate) and negative (96% ethanol) controls.

Results:

Inhibition halos of 26.4±2.6 and 18.2±1.8 mm were observed for the autumn and summer propolis extracts, respectively, while those of the negative and positive controls were 0 and 13 mm, respectively. These differences were statistically analyzed using Student’s t-test.

Conclusion:

The significantly higher growth of S. mutans in the extracts made from propolis collected in autumn than that grown on extracts collected in summer indicates that the season in which propolis is collected does indeed influence its antibacterial activity.

Gas production and in vitro degradability of sheep diets containing propolis ethanolic extract

SUMMARY This study evaluated the influence of the propolis ethanolic extract (PEE) on gas production and in vitro degradability of sheep diets. Five experimental diets (treatments) were evaluated: without addition of PEE; 6 mL PEE; 12 mL PEE; 24 mL PEE and 36 mL PEE/kg concentrate. The experimental diet consisted of 50% elephant grass (Pennisetum purpureum) and 50% concentrate. There was a quadratic effect (P <0.05) for the volumes of total gas production (Vt), gases produced by the rapid degradation fractions (Vf1), and for in vitro degradability at 120 hours (Deg120), where the lowest values of Vt, Vf1 and Deg120, were found for the inclusion of 9.4 mL PEE/kg concentrate. Gas production by fermentation of the slow degradation fraction (Vf2) presented a mean of 25 mL/g DM (P <0.05). The colonization time of food particles (λ) significantly reduced (P<0.05) with increasing inclusion of PEE. Thus, it can be concluded that the PEE up to the inclusion of 9.4 mL/kg concentrate was efficient in inhibiting in vitro total gas production and from the fractions of rapid degradation by 9.9 and 15.3%, respectively, in addition to promoting a reduction of 5.3% in degradability after 120 h incubation in diets with a concentrate: forage ratio of 50:50. Thus, the inhibition in gas production was proportionally greater than the reduction of degradability.

Brazilian propolis extract used as an additive to decrease methane emissions from the rumen microbial population in vitro

Propolis is a product that is rich in phenolic compounds and can be utilized in animal nutrition as a dietary additive. In this study, the effects of a Brazilian green propolis extract on rumen fermentation and gas production were determined. The fate of propolis phenolic compounds in the rumen medium was also investigated. Fermentation was done in 24-h batches over three periods. Inoculates were obtained from cows fed on grassland hay and concentrate. Propolis extract in a hydroalcoholic solution was applied at increasing doses to the substrate (1 to 56 g/kg). The fermentation substrate consisted on a mixture of alfalfa hay, soybean meal, and wheat grain mixture in dry matter. After 24 h of fermentation, seven new compounds were observed in the medium in amounts that correlated to the propolis dose. The dose of propolis extract linearly decreased the pH of the medium and linearly increased propionate production, which reduced the acetate-to-propionate ratio and influenced the total production of short-chain fatty acids. Propolis also linearly reduced methane production and increased the carbon dioxide-to-methane ratio. Ammonia nitrogen levels and in vitro digestibility of organic matter were similar among the treatments. The combination of increased propionate production and decreased methane production suggests better energy utilization from the feed.