The objective of this study was to determine the extraction yield, the content of bioactive compounds and in vitro antioxidant activity of different extracts from Moringa oleifera (MO) leaves, and their potential use as a natural feed additive for ruminant diets. For the preparation of MO extracts, three treatments were used: (1) MO extract in distilled water (MOEW, 0%), (2) ethanol-water (MOEEW, 50%) and (3) absolute ethanol (MOEE, 100%). The extraction yield and the antioxidant activity measured with the DPPH assay in the MO extracts were higher for MOEW and MOEEW. From all treatments, MOEEW had the highest antioxidant activity evaluated with the ABTS assay and showed a higher content of bioactive compounds. On the other hand, the principal component analysis showed that the first two principal components explained 96.5% of the variability of the data. The variables that contributed to the greatest variation were condensed tannins (CT), total phenolic compounds (TPC), total flavonoids (TF), and extraction yield. A high correlation (p ≤ 0.001) was observed between TPC and extraction yield with r2 = 0.989. The content of bioactive compounds and antioxidant activity was higher in the MOEEW extract; therefore, its inclusion in ruminant diets can be suggested to potentially improve their productivity and product quality.

This study determined productive performance, ruminal fermentation kinetics and rumen ciliate protozoa in hair sheep lambs fed different levels of olive oil. Twenty-four growing lambs were used, with an initial live weight of 10.5 ± 2.9 kg, and randomly assigned into four treatments (six animals per treatment) containing increasing levels of extra virgin olive oil (0, 2, 4 and 6% of dry matter). Animals were fed for 80 days, and sampling was carried out weekly. Intake of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and metabolizable energy (ME) differed between treatments (p < 0.05), with a linear and cubic tendency to decrease when oil concentrations were increased. Digestibility coefficients of OM, CP and NDF were not affected; however, the relationship between total intake and nutrient digestibility (DM, OM, NDF, ADF) increased with 2% DM olive oil. Compared with all treatments, the concentration of propionic acid increased by 16% with 4% olive oil. The intake of olive oil did not affect the protozoa population and live weight gain. Overall, the inclusion of olive oil in low concentrations (2% of DM) positively influences feed intake and nutrient digestibility in hair sheep lambs.

The objective of this study was to evaluate the effects of dietary supplementation with flavonoids (FLAs) on animal performance, diet digestibility, antioxidant status in blood serum, rumen parameters, meat quality, and milk composition in beef and dairy cattle through a meta-analysis. Thirty-six peer-reviewed publications were included in the data set. The weighted mean differences (WMD) between the FLAs treatments and the control treatment were used to assess the effect size. Dietary supplementation with FLAs decreased feed conversion ratio (WMD = −0.340 kg/kg; p = 0.050) and increased (p &lt; 0.05) dry matter intake (WMD = 0.191 kg/d), dry matter digestibility (WMD = 15.283 g/kg of DM), and daily weight gain (WMD = 0.061 kg/d). In blood serum, FLAs supplementation decreased the serum concentration of malondialdehyde (WMD = −0.779 nmol/mL; p &lt; 0.001) and increased (p &lt; 0.01) the serum concentration of superoxide dismutase (WMD = 8.516 U/mL), glutathione peroxidase (WMD = 12.400 U/mL) and total antioxidant capacity (WMD = 0.771 U/mL). A higher ruminal propionate concentration (WMD = 0.926 mol/100 mol; p = 008) was observed in response to FLAs supplementation. In meat, the dietary inclusion of FLAs decreased (p &lt; 0.05) shear force (WMD = −1.018 kgf/cm2), malondialdehyde content (WMD = −0.080 mg/kg of meat), and yellowness (WMD = −0.460). Supplementation with FLAs decreased milk somatic cell count (WMD = −0.251 × 103 cells/mL; p &lt; 0.001) and increased (p &lt; 0.01) milk production (WMD = 1.348 kg/d), milk protein content (WMD = 0.080/100 g) and milk fat content (WMD = 0.142/100 g). In conclusion, dietary supplementation with FLAs improves animal performance and nutrient digestibility in cattle. In addition, FLAs improve the antioxidant status in blood serum and the quality of meat and milk.

Soil respiration is a very important component of the global carbon cycle, considered as the second most important carbon (C) flux to the atmosphere and is directly affected by global warming (Xu & Qi, 2001; Bond-Lamberty et al., 2004; Arredondo et al., 2018). It is defined as the sum of autotrophic respiration (i.e. roots and fungi) and heterotrophic respiration (i.e. soil microorganisms that break down organic matter and soil fauna) and is influenced by environmental factors, such as soil and ambient temperature, water content and photosynthetically active radiation (Raich & Schlesinger, 1992; Zimmermann et al., 2009; Cueva et al., 2016). Approximately 30% of the emissions of carbon dioxide (CO 2) come from changes in land use, particularly from deforestation to establish pastures for extensive livestock production (Schimel et al., 2001; Villanueva, 2014). In Mexico, it is estimated that 30%-50% of soil organic carbon

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