Free and Microencapsulated Essential Oils Incubated In Vitro: Ruminal Stability and Fermentation Parameters

In vitro fermentation end-products and rumen microbiome as influenced by microencapsulated phytonutrient pellets (LEDRAGON) supplementation

The objective of this study was to investigate the effect of microencapsulated bioactive compounds from lemongrass mixed dragon fruit peel pellet (MiEn-LEDRAGON) supplementation on fermentation characteristics, nutrient degradability, methane production, and the microbial diversity using in vitro gas production technique. The study was carried out using a completely randomized design (CRD) with five levels of MiEn-LEDRAGON supplementation at 0, 1, 2, 3, and 4% of the total dry matter (DM) substrate. Supplementation of MiEn-LEDRAGON in the diet at levels of 3 or 4% DM resulted in increased (p < 0.05) cumulative gas production at 96 hours (h) of incubation time, reaching up to 84.842 ml/ 0.5 g DM. Furthermore, supplementation with 3% MiEn-LEDRAGON resulted in higher in vitro nutrient degradability and ammonia-nitrogen concentration at 24 h of the incubation time when compared to the control group (without supplementation) by 5.401% and 11.268%, respectively (p < 0.05). Additionally, supplementation with MiEn-LEDRAGON in the diet led to an increase in the population of Fibrobacter succinogenes at 24 h and Butyrivibrio fibrisolvens at 12 h, while decreasing the population of Ruminococcus albus, Ruminococcus flavefaciens, and Methanobacteriales (p < 0.05). Moreover, supplementation of MiEn-LEDRAGON in the diet at levels of 2 to 4% DM resulted in a higher total volatile fatty acids (VFA) at 24 h, reaching up to 73.021 mmol/L (p < 0.05). Additionally, there was an increased proportion of propionic acid (C3) and butyric acid (C4) at 12 h (p < 0.05). Simultaneously, there was a decrease in the proportion of acetic acid (C2) and the ratio of acetic acid to propionic acid (C2:C3), along with a reduction of methane (CH4) production by 11.694% when comparing to the 0% and 3% MiEn-LEDRAGON supplementation (p < 0.05). In conclusion, this study suggests that supplementing MiEn-LEDRAGON at 3% of total DM substrate could be used as a feed additive rich in phytonutrients for ruminants.

In vitro evaluation of microencapsulated organic acids and pure botanicals as a supplement in lactating dairy cows diet on in vitro ruminal fermentation

The utilization of microencapsulated organic acids and pure botanicals (mOAPB) is widely used in the monogastric livestock industry as an alternative to antibiotics; in addition, it can have gut immunomodulatory functions. More recently, an interest in applying those compounds in the ruminant industry has increased; thus, we evaluated the effects of mOAPB on ruminal fermentation kinetics and metabolite production in an in vitro dual-flow continuous-culture system. For this study, two ruminal cannulated lactating dairy Holstein cows were used as ruminal content donors, and the inoculum was incubated in eight fermenters arranged in a 4 × 4 Latin square design. The basal diet was formulated to meet the nutritional requirements of a 680-kg Holstein dairy cow producing 45 kg/d of milk and supplemented with increasing levels of mOAPB (0; 0.12; 0.24; or 0.36% of dry matter [DM]), which contained 55.6% hydrogenated and refined palm oil, 25% citric acid, 16.7% sorbic acid, 1.7% thymol, and 1% vanillin. Diet had 16.1 CP, 30.9 neutral detergent fiber (NDF), and 32.0 starch, % of DM basis, and fermenters were fed 106 g/d split into two feedings. After a 7 d adaptation, samples were collected for 3 d in each period. Samples of the ruminal content from the fermenters were collected at 0, 1, 2, 4, 6, and 8 h postmorning feeding for evaluation of the ruminal fermentation kinetics. For the evaluation of the daily production of total metabolites and for the evaluation of nutrient degradability, samples from the effluent containers were collected daily at days 8 to 10. The statistical analysis was conducted using MIXED procedure of SAS and treatment, time, and its interactions were considered as fixed effects and day, Latin square, and fermenter as random effects. To depict the treatment effects, orthogonal contrasts were used (linear and quadratic). The supplementation of mOAPB had no major effects on the ruminal fermentation, metabolite production, and degradability of nutrients. The lack of statistical differences between control and supplemented fermenters indicates effective ruminal protection and minor ruminal effects of the active compounds. This could be attributed to the range of daily variation of pH, which ranged from 5.98 to 6.45. The pH can play a major role in the solubilization of lipid coat. It can be concluded that mOAPB did not affect the ruminal fermentation, metabolite production, and degradability of dietary nutrients using an in vitro rumen simulator.

Bioprospecting essential oils of exotic species as potential mitigations of ruminant enteric methanogenesis

The inclusion of essential oils (EOs) in the diet of ruminants is one of the strategies used to alter ruminal microbial fermentation, improving feed efficiency, while simultaneously reducing enteric methane (CH4) production. This study aimed to evaluate the effects of three new EOs from plants exotic to the Azores, Pittosporum undulatum (PU), Hedychium gardnerianum (HG), and Cryptomeria japonica (CJ), on biogas production kinetics and in vitro CH4 production. Three levels of EOs (40, 80, and 120 μL/g dry matter (DM) were added to the basal diet to evaluate ruminal fermentation using the in vitro gas production technique. Added 800 mL of rumen inoculum with 5 g DM of the basal diet (BD) to all experimental units for 96 h, except for the blanks, to which only the inoculum was added. The total gas and CH4 produced by treatment incubation were recorded every hour after incubation until 96 h. The results showed that the gas production decreased significantly (P < 0.001) at 24 and 96 h after incubation, in the medium and high levels, with the essential oils PU, CJ, and HG treatment, when compared to the control treatment. The same significant differences (P < 0.001) were observed in in vitro CH4 production. The greatest reduction was noted with the addition of PUEO at the highest concentration (120 μL), which allowed a reduction in CH4 production at 24 h of 47% (P < 0.01). There was an interaction effect between EOs and concentration levels for all variables (P < 0.001). A decrease in total volatile fat acid (VFA) concentration (P < 0.05) was recorded compared to control, as well as the insoluble fraction and the potential degradation of the BD when EOs were included in the diet. In conclusion, the addition of EOs to the BD effectively reduced total enteric gas emissions and mitigated CH4 production. The most significant reduction of CH4 (47% in 24 h of incubation) occurs when 120 μL PUEO is added to each gram DM. The inclusion of OEs in the BD also affected the gas production kinetics and fermentation parameters.

Spray drying encapsulation of essential oils; process efficiency, formulation strategies, and applications

Essential oils (EOs) have many beneficial qualities, including antimicrobial, antioxidant, antiviral, and antifungal activities, along with good aroma, which have played a significant role in pharmaceutical, textile, and food industries. However, their high volatility and sensibility to external factors, as well as susceptibility to deterioration caused by environmental and storage conditions, or even common processing, and consequently limited water solubility, makes it difficult to incorporate them into aqueous food matrices and limits their industrial application. Spray-drying encapsulation has been proposed as a solution and a challenging research field to retard oil oxidation, extend EO's shelf life, improve their physicochemical stability, achieve controlled release, suggest novel uses, and therefore boost their added value. The objective of this review is to discuss various used wall materials, infeed emulsion properties, the main formulation and process variables affecting the physicochemical properties and release characteristics of the EOs-loaded particles obtained by spray-drying, the stability of EOs during storage, and the applications of encapsulated EOs powders in foods and nutrition, pharmaceuticals, and textile industries. The current review also summarizes recent advances in spray drying approaches for improving encapsulation efficiency, flavor retention, controlled release, and applicability of encapsulated EOs, thereby expanding their use and functionalities.

Effects of Essential Oil Blends on In Vitro Apparent and Truly Degradable Dry Matter, Efficiency of Microbial Production, Total Short-Chain Fatty Acids and Greenhouse Gas Emissions of Two Dairy Cow Diets

The current study evaluated nine essential oil blends (EOBs) for their effects on ruminal in vitro dry matter digestibility (IVDMD), efficiency of microbial production, total short-chain fatty acid concentration (SCFA), total gas, and greenhouse gas (GHG) emissions using two dietary substrates (high forage and high concentrate). The study was arranged as a 2 × 2 × 9 + 1 factorial design to evaluate the effects of the nine EOBs on the two dietary substrates at two time points (6 and 24 h). The inclusion levels of the EOBs were 0 µL (control) and 100 µL with three laboratory replicates. Substrate × EOBs × time interactions were not significant (p > 0.05) for total gas and greenhouse gas emissions. The inclusion of EOBs in the diets resulted in a reduction (p < 0.001) in GHG emissions, except for EOB1 and EOB8 in the high concentrate diet at 6 h and for EOB8 in the high forage diet at 24 h of incubation. Diet type had no effect on apparent IVDMD (IVADMD) whereas the inclusion of EOBs reduced (p < 0.05) IVADMD with higher values noted for the control treatment. The efficiency of microbial production was greater (p < 0.001) for EOB treatments except for EOB1 inclusion in the high forage diet. The inclusion of EOBs affected (p < 0.001) the total and molar proportion of volatile fatty acid concentrations. Overall, the inclusion of the EOBs modified the rumen function resulting in improved efficiency of microbial production. Both the apparent and truly degraded DM was reduced in the EOB treatments. The inclusion of EOBs also resulted in reduced GHG emissions in both diets, except for EOB8 in the high forage diet which was slightly higher than the control treatment.

Effects of essential oil mixtures on nitrogen metabolism and odor emission via in vitro simulated digestion and in vivo growing pig experiments

BACKGROUND

Essential oils (EOs) are extensively used in swine production because of their bioactive action in gut health. In addition, some EOs have the potential to reduce waste emission. The present study aimed to find an optimal combination of carvacrol, thymol and cinnamaldehyde to promote nitrogen utilization and reduce waste emission by a model in vitro and an animal study.

RESULTS

In the study in vitro, various dosages of essential oils (EOs) were used to evaluate the effect on nitrogen metabolism through a three-step model. Compared with other EO combinations, 2EO (10 ppm cinnamaldehyde and 20 ppm thymol), and 3EO (10 ppm cinnamaldehyde, 20 ppm thymol and 200 ppm carvacrol) displayed greater nitrogen digestibility, lesser ammonia production and lower activity of microbial enzymes. In the animal study, growing male Landrace × Yorkshire pigs (initial body weight: 31.8 ± 3.3 kg, n = 18) were randomly divided into three groups and fed the control, 2EO or 3EO diet for 4 weeks. Pigs fed 3EO exhibited the greatest nitrogen digestibility (85.4%, P < 0.05). EO supplementation decreased the emission of ammonia (130-140 vs. 223 mg g^-1 ) and total fecal nitrogen (8.0-9.9 vs. 12.4 g d^-1 ) (P < 0.05). Microbial protease and urease activities were inhibited by EO treatments (P < 0.01). Both 2EO and 3EO reduced the content of indole and 3-methylindole (P < 0.01), whereas only 2EO caused a decrease in p-cresol (P < 0.1).

CONCLUSION

2EO was suitable for reducing waste emission and odorous compounds in growing pigs, whereas 3EO was optimal for increasing nitrogen utilization and partially reducing waste odorous compounds. © 2021 Society of Chemical Industry.