Effect of Dietary Guanidinoacetic Acid Levels on the Mitigation of Greenhouse Gas Production and the Rumen Fermentation Profile of Alfalfa-Based Diets.

The objective of this study was to evaluate the effect of different percentages of alfalfa (Medicago sativa L.) hay (AH) and doses of guanidinoacetic acid (GAA) in the diet on the mitigation of greenhouse gas production, the in vitro rumen fermentation profile and methane (CH4) conversion efficiency. AH percentages were defined for the diets of beef and dairy cattle, as well as under grazing conditions (10 (AH10), 25 (AH25) and 100% (AH100)), while the GAA doses were 0 (control), 0.0005, 0.0010, 0.0015, 0.0020, 0.0025 and 0.0030 g g-1 DM diet. With an increased dose of GAA, the total gas production (GP) and methane (CH4) increased (p = 0.0439) in the AH10 diet, while in AH25 diet, no effect was observed (p = 0.1311), and in AH100, GP and CH4 levels decreased (p = 0.0113). In addition, the increase in GAA decreased (p = 0.0042) the proportion of CH4 in the AH25 diet, with no influence (p = 0.1050) on CH4 in the AH10 and AH100 diet groups. Carbon monoxide production decreased (p = 0.0227) in the AH100 diet with most GAA doses, and the other diets did not show an effect (p = 0.0617) on carbon monoxide, while the production of hydrogen sulfide decreased (p = 0.0441) in the AH10 and AH100 diets with the addition of GAA, with no effect observed in association with the AH25 diet (p = 0.3162). The pH level increased (p < 0.0001) and dry matter degradation (DMD) decreased (p < 0.0001) when AH was increased from 10 to 25%, while 25 to 100% AH contents had the opposite effect. In addition, with an increased GAA dose, only the pH in the AH100 diet increased (p = 0.0142 and p = 0.0023) the DMD in the AH10 diet group. Similarly, GAA influenced (p = 0.0002) SCFA, ME and CH4 conversion efficiency but only in the AH10 diet group. In this diet group, it was observed that with an increased dose of GAA, SCFA and ME increased (p = 0.0002), while CH4 per unit of OM decreased (p = 0.0002) only with doses of 0.0010, 0.0015 and 0.0020 g, with no effect on CH4 per unit of SCFA and ME (p = 0.1790 and p = 0.1343). In conclusion, the positive effects of GAA depend on the percentage of AH, and diets with 25 and 100% AH showed very little improvement with the addition of GAA, while the diet with 10% AH presented the best results.

Marine Microalgae as a Nutritive Tool to Mitigate Ruminal Greenhouse Gas Production: In Vitro Fermentation Characteristics of Fresh and Ensiled Maize (Zea mays L.) Forage.

The aim of the present study was to evaluate the effects of marine microalgae (Dunaliella salina) as a food additive on biogas (BG), methane (CH4), carbon monoxide (CO), and hydrogen sulfide (H2S) production kinetics, as well as in in vitro rumen fermentation and the CH4 conversion efficiency of different genotypes of maize (Zea mays L.) and states of forage. The treatments were characterized by the forage of five maize genotypes (Amarillo, Montesa, Olotillo, Tampiqueño, and Tuxpeño), two states of forage (fresh and ensiled), and the addition of 3% (on DM basis) of microalgae (with and without). The parameters (b = asymptotic production, c = production rate, and Lag = delay phase before gas production) of the production of BG, CH4, CO, and H2S showed an effect (p < 0.05) of the genotype, the state of the forage, the addition of the microalgae, or some of its interactions, except for the time in the CO delay phase (p > 0.05). Moreover, the addition of microalgae decreased (p < 0.05) the production of BG, CH4, and H2S in most of the genotypes and stages of the forage, but the production of CO increased (p < 0.05). In the case of fermentation characteristics, the microalgae increased (p < 0.05) the pH, DMD, SCFA, and ME in most genotypes and forage states. With the addition of the microalgae, the fresh forage from Olotillo obtained the highest pH (p < 0.05), and the ensiled from Amarillo, the highest (p < 0.05) DMD, SCFA, and ME. However, the ensiled forage produced more (p < 0.05) CH4 per unit of SFCA, ME, and OM, and the microalgae increased it (p < 0.05) even more, and the fresh forage from Amarillo presented the highest (p < 0.05) quantity of CH4 per unit of product. In conclusion, the D. salina microalga showed a potential to reduce the production of BG, CH4, and H2S in maize forage, but its effect depended on the chemical composition of the genotype and the state of the forage. Despite the above, the energy value of the forage (fresh and ensiled) improved, the DMD increased, and in some cases, SCFA and ME also increased, all without compromising CH4 conversion efficiency.

Moringa oleifera as a Natural Alternative for the Control of Gastrointestinal Parasites in Equines: A Review.

Studies have shown a wide variety of parasites that infect horses, causing major gastrointestinal damage that can lead to death, and although the main method of control has been synthetic anthelmintics, there are parasites that have developed resistance to these drugs. For generations, plants have been used throughout the world as a cure or treatment for countless diseases and their symptoms, as is the case of Moringa oleifera, a plant native to the western region. In all its organs, mainly in leaves, M. oleifera presents a diversity of bioactive compounds, including flavonoids, tannins, phenolic acids, saponins, and vitamins, which provide antioxidant power to the plant. The compounds with the greatest antiparasitic activity are tannins and saponins, and they affect both the larvae and the oocytes of various equine gastrointestinal parasites. Therefore, M. oleifera is a promising source for the natural control of gastrointestinal parasites in horses.

Impact of Co-Ensiling of Maize with Moringa oleifera on the Production of Greenhouse Gases and the Characteristics of Fermentation in Ruminants.

The objective of this experiment was to evaluate the impact of maize co-ensiling with increasing percentages of MOL forage on the kinetics of biogas, methane (CH4), carbon monoxide (CO) and hydrogen sulfide (H2S) production, as well as the characteristics of ruminal fermentation and CH4 conversion efficiency, using steers (STI) and sheep (SHI) as inoculum sources. With the STI, the inclusion of MOL reduced (linear: p ≤ 0.0199; quadratic: p ≤ 0.0267) biogas production (mL g-1 DM incubated and degraded), CH4 (mL g-1 DM degraded), CO (mL g-1 DM degraded), and H2S (mL g-1 DM incubated and degraded), without affecting (p > 0.05) the parameters (b = asymptotic gas, c = rate of gas production and Lag = initial delay time before gas production) of CH4 and H2S, and the proportion and production of CH4 per kg of dry matter (DM). In addition, with this inoculum, pH, and dry matter degradation (DMD) increased (linear: p ≤ 0.0060), and although short-chain fatty acids (SCFA) and metabolizable energy (ME) decreased (linear: p < 0.0001; quadratic: p ≤ 0.0015), this did not affect (p > 0.05) the CH4 conversion efficiency. Meanwhile, with the SHI, the inclusion of MOL only decreased (linear: p ≤ 0.0206; quadratic: p ≤ 0.0003) biogas per dry matter (DM) degraded and increased (linear: p ≤ 0.0293; quadratic: p ≤ 0.0325) biogas per DM incubated, as well as the production (mL g-1 DM incubated and degraded and g-1 kg DM) and proportion of CH4, and CO per DM incubated and degraded. In addition, it did not impact (p > 0.05) on the CH4 and H2S parameters, and in the H2S by DM incubated and degraded, and although it increased (linear: p ≤ 0.0292; quadratic: p ≤ 0.0325) the DMD, SCFA, and ME, it was inefficient (quadratic: p ≤ 0.0041) in CH4 conversion. It is concluded that regardless of the percentage of MOL, the STI presented the highest values in the production of biogas, CH4, H2S, DMD, SCFA, and ME, and the lowest pH, so it turned out to be the most efficient in CH4 conversion, while with the SHI only the highest production of CO and pH was obtained, and the lowest DMD, SCFA, and ME, so it was less efficient compared to STI.