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Leverage of Essential Oils on Faeces-Based Methane and Biogas Production in Dairy Cows
Currently, there is an ongoing intensive search for solutions that would effectively reduce greenhouse gas emissions (mainly methane) into the environment. From a practical point of view, it is important to reduce methane emissions from cows in such a way as to simultaneously trim emissions from the digestive system and increase its potential production from feces, which is intended as a substrate used in biogas plants. Such a solution would not only lower animal-based methane emissions but would also enable the production of fuel (in chemical form) with a high yield of methane from biogas, which would boost the economic benefits and reduce the use of fossil fuels. We tested the effect of administering an essential oil blend consisting of 5.5% oils and fats on methane and biogas production from dairy cow feces during fermentation. Three subsequent series (control and experimental) were conducted in dairy cows fed a total mixed ration (TMR) rich in brewer’s cereals and beet pulp, with 20% dry matter (DM) of the total diet. Cows from the experimental group received 20 g/cow/day of essential oil blend, namely a commercial additive (CA). The study showed that CA can increase the production of methane and biogas from dairy cow feces. It can be concluded that in the experimental groups, approx. 15.2% and 14.4% on a fresh matter basis and 11.7% and 10.9% on a dry matter basis more methane and biogas were generated compared to the control group, respectively. Therefore, it can be assumed that the use of CA in cow nutrition improved dietary digestibility, which increased the efficiency of the use of feces organic matter for biogas production.
Effects of a Multi-Strain Lactic and Propionic Acid Bacteria Inoculant on Silage Quality, Methane Emissions, Milk Composition, and Rumen Microbiome
Ensiling grass with microbial inoculants is a promising strategy to enhance forage quality, animal performance, and environmental sustainability. This study evaluated the effects of a multi-strain inoculant (Lactobacillus plantarum, L. buchneri, Propionibacterium acidipropionici, and P. thoeni) on silage fermentation, nutrient digestibility, milk production, methane emissions, and rumen microbiota in dairy cows. In a 2 × 2 crossover design, 24 lactating Polish Holstein–Friesians were fed total mixed rations differing only in grass silage treated with or without inoculant. Inoculated silage had lower pH (4.56 vs. 5.06; p = 0.02) and higher crude protein (129 vs. 111 g/kgDM; p < 0.05). Cows fed inoculated silage showed higher ruminal propionate (28.3 vs. 26.3 mM; p = 0.03), reduced ammonia (7.61 vs. 8.67 mM; p = 0.02), and fewer protozoa (1.21 vs. 1.66 × 105/mL; p = 0.03). Nutrient digestibility improved (p < 0.05), while methane emissions declined both per cow (368 vs. 397 g/d; p = 0.01) and per kgDMI (15.1 vs. 16.5; p = 0.01). Milk yield increased (p = 0.04), and the fatty acid profile improved. Our study revealed that cows fed inoculated silage had higher nutrient digestibility, lower methane emissions, and microbial shifts in the rumen detected by 16S rRNA sequencing (p < 0.05).
From Waste to Feed: Enhancing Sustainability in Ruminant Nutrition Through Cashew Apple Utilization – A Review
Abstract Growing global demand for livestock products has intensified the need for sustainable feed resources in ruminant nutrition, particularly in developing regions. With feed costs comprising up to 75% of production expenses, exploring alternative feed sources can offer both economic and environmental benefits. This study explored the potential of cashew apple (CA) as a novel and sustainable by-product for ruminants by reviewing relevant articles from databases such as Scopus, Web of Science, PubMed, and Google Scholar. CA has an average proximate composition (dry matter basis) of 130 g/kg crude protein, 71.7 g/kg crude fibre, 61.2 g/kg ether extract, 49.3 g/kg ash, 640 g/kg nitrogen free extract, and 2973 kcal/kg metabolizable energy, making it a valuable addition to ruminant diets. It can reduce reliance on traditional and high-cost feed sources and mitigate environmental pollution by reducing waste and contributing to circular agricultural practices. However, limitations such as high moisture content in fresh cashew fruit, seasonal availability, and rapid spoilage necessitate effective processing methods. There is a knowledge gap on the use of CA in ruminant diets, and there is a need to assess its impact on ruminal pH, short-chain fatty acids production, ammonia production, other rumen fermentation profiles, and animal performance. Based on the quantitative data of this study about the proximate composition of CA and some animal studies, it could be a viable and eco-friendly supplement to the ruminant diets. Addressing its storage and preservation challenges can unlock its potential in diversified, eco-friendly ruminant systems.
Effect of Feeding Dried Apple Pomace on Ruminal Fermentation, Methane Emission, and Biohydrogenation of Unsaturated Fatty Acids in Dairy Cows
Industrial fruit by-products are now being utilized as animal feeds for several reasons. They may substitute the conventional cereal feeds, and also offer economic and environmental benefits. One of the most important industrial fruit by-products is apple pomace, which can be used as a source of energy in the ration of ruminant species, including dairy cattle. The aim of the present study was to evaluate the effect of feeding dried apple pomace to dairy cattle on ruminal fermentation, fatty acid concentration, microbial populations, and methane production. The experiment lasted 64 days and was conducted with 4 cannulated commercial dairy cows. The control animals received a standard diet, while the experimental animals was fed a standard diet supplemented with 150 g/kg DM dried apple pomace. Ruminal fluid samples were collected at three different time intervals. The samples were obtained at 0-, 3-, and 6-h post-feeding. The ruminal fluid was used to assess the ammonia concentration, pH, volatile fatty acids (VFA), long-chain fatty acids (FA), microbial population. A number of ruminal fermentation variables changed as a result of the addition of dried apple pomace to the standard diet. Ruminal pH slightly increased (p < 0.01) while the ammonia concentration decreased (p < 0.01) by 46%. There was a significant decrease in total protozoa count (p < 0.01) and an increase (p < 0.01) in total volatile fatty acids. In addition, there was a decline in methane emission (p = 0.05) by 8% due to dried apple pomace feeding. To sum up, this study demonstrated a positive effect of 150 g/kg DM dietary dried apple pomace on ruminal metabolism including a decrease in ammonia concentration and methane emissions, alongside with an increase in total ruminal VFAs, higher nutrient digestibility, and milk production. Also, beneficial changes to the ruminal fatty acid profile resulting from reduced biohydrogenation were observed although a decreased content of the C18:2 cis 9 trans 11 isomer was also noticed. The dietary inclusion of DAP can serve as a valuable, sustainable, and environmentally friendly dietary component for dairy cows.
Bioactive Compounds, Ruminal Fermentation, and Anthelmintic Activity of Specialty Coffee and Spent Coffee Grounds In Vitro
We quantified the bioactive compounds of Ethiopian coffee (ETH), spent coffee grounds SCGs from ETH (SCG-ETH), and mixed SCGs (SCG-MIX) prepared by filtration methods and investigated the effect of SCG-ETH on ruminal fermentation as well as the anthelmintic activity of ETH. Three substrates, meadow hay (MH)-barley grain (MH-BG), MH-SCG-ETH, and BG-SCG-ETH (1:1 w/w), were fermented using an in vitro gas production technique. The bioactive compounds were quantitatively analyzed using ultra-high-resolution mass spectrometry. We performed an in vitro larval development test to determine the anthelmintic effect of an aqueous extract of ETH against the gastrointestinal nematode (GIN) Haemonchus contortus. The total content of bioactive compounds was highest in SCG-ETH, followed by SCG-MIX and ETH (35.2, 31.2, and 20.9 mg/g dry matter, respectively). Total gas and methane production (p < 0.001) were decreased by both MH-SCG-ETH and BG-SCG-ETH. The in vitro digestibility of dry matter was higher for MH-SCG-ETH and BG-SCG-ETH than for MH-BG. The aqueous ETH extract exhibited a strong larvicidal effect, with a mean lethal dose of 13.2 mg/mL for 50% mortality and 31.9 mg/L for 99% mortality. SCG substrates have the potential to modulate ruminal fermentation and serve as a source of anthelmintic bioactive compounds against GINs in ruminants.
Potential of chicory (Cichorium intybus) sward to improve growth performance and the fatty acid profile of rumen fluid, liver, muscle, and subcutaneous fat tissues of lamb
Insights into the role of bioactive plants for lambs infected with Haemonchus contortus parasite
Bioactive plants provide therapeutic and prophylactic effects to ruminants. We determined the effect of grazing on natural meadow grassland enriched with experimentally sown chicory (Cichorium intybus) on parasitological status, pasture larval infectivity, antioxidant parameters, and the histology of abomasal tissue in lambs experimentally infected with the parasitic gastrointestinal nematode (GIN) Haemonchus contortus. We also qualitatively identified the main polyphenols in the meadow grassland and phenolic metabolites in the feces of the lambs. Sixteen lambs were orally infected with approximately 5,000 infective larvae (L3) of H. contortus. The lambs were divided into two groups: lambs grazing on a plot consisting exclusively of meadow pasture which serves as control group and lambs grazing on a plot where approximately 25% of a meadow grassland was reclaimed with chicory. The experimental period was 144 days. The number of eggs per gram (EPG) of feces was quantified on D21, D34, D48, D62, D76, D89, D103, D118, D131, and D144 post-infection. Pasture contamination with H. contortus L3 was examined. EPG in both groups of lambs was highest at D34. Egg shedding was significantly lower in both groups from D48 onwards, with a reduction of >95% from D103 onwards. Pasture contamination with L3 was highest at D41 but was then significantly lower in both groups. The total antioxidant capacity, the activity of glutathione peroxidase and the concentration of malondialdehyde in the serum changed significantly during the experiment (p < 0.003, < 0.001, and < 0.016, respectively). At least 54 species of meadow plants were identified on both pasture plots; plant bioactive compounds identified were mainly phenolic acids, flavonoids, and glucosides. Phenolic metabolites (e.g., coumaric acid, chicory acid, salvigenin, and esters of gallic acid) were identified in the feces of the lambs. In some lambs, the morphological observation identified small histopathological changes in the abomasal tissues typical of hemonchosis. Both the natural meadow pasture and the pasture enriched with experimentally sown chicory slowed the dynamics of GIN infection and pasture contamination with L3 by mobilizing the antioxidant defensive system and gradually increasing the resistance of the infected lambs, probably due to the beneficial effects of plant bioactive substances.
Effect of zinc oxide nanoparticle supplementation on parasite infection and rumen environment of grazing lambs
This study investigated the effect of zinc nanoparticles (ZnO-NPs) on the growth parameters, parasitological status, ruminal fermentation, and histopathology of lambs that were experimentally infected with Haemonchus contortus larvae. The infected lambs were divided into two groups ( n = 10/group) and grazed on pasture while being fed one of two diets: a control diet consisting of 350 g/d of a dietary concentrate (CONTROL), and a diet consisting of 350 g/d of concentrate enriched with ZnO-NPs (ZINC). Pasture aboveground plant coverage and plant taxa from phytosociological relevés were used as descriptors to investigate differences in vegetation based on plant medicinal properties and the nutritional value. Communities dominated by plants with medicinal properties were mainly found in the CONTROL group's pasture, while the pasture of the ZINC group contained most plants with outstanding nutritional value. The number of eggs per gram of feces was quantified on days D14, D20, D28, D42, D56, D70, D84, D98, and D107 post-infection. There was a significant decrease in egg shedding from D42 onwards in the ZINC group, and from D56 and D70 onwards in the CONTROL group. The ruminal concentration of ammonia nitrogen ( p = 0.018), n -butyrate ( p = 0.025), n-valerate ( p = 0.002), total protozoa count ( p < 0.001), and the enzymatic activities of α-amylase ( p < 0.001) and xylanase ( p = 0.006) were significantly higher in the ZINC group than in the CONTROL group. The molar proportion of acetate was lower ( p = 0.011) in the ZINC group than in the CONTROL group. Morphological observations of the rumen indicated that the homogeneity of the ruminal papillae was slightly impaired, the lamina propria was inflamed, or lymphocytes had infiltrated. In conclusion, the dynamics of gastrointestinal nematode infection were significantly reduced, probably due to the medicinal and nutritional properties of the pasture plants. This effect was also enhanced by the supplementation with ZnO nanoparticles, which possess strong anthelmintic potential.