Selenium supplementation improves nutrient intake and digestibility, and mitigates CH4 emissions from sheep grazed on the mixed pasture of alfalfa and tall fescue.

Low selenium (Se) in soil and forage can adversely affect on the quality of animal-derived foods, and hence on human health. Lambs grazed on mixed pastures of alfalfa (Medicago sativa) and tall fescue (Festuca arundinacea) were supplemented with five levels of Se [0, 3, 6, 9 and 12 µg/kg body weight (BW)]. The intake of dry matter (DM) and organic matter (OM) varied with the level of Se supplementation, with a peak at 6 µg Se per kg BW (p ≤ 0.05). Gross energy (GE) intake, digestive energy (DE) intake and metabolic energy (ME) intake were higher at 6 µg Se per kg BW than at other Se levels (p < 0.01); in addition, methane energy (CH4 -E) output was lower at 6 µg Se per kg BW. Supplementation with Se significantly increased nitrogen (N) intake, faecal N and urine N, for which the peak values were 20.2 g N/, 5.62 g N/day and 7.92 g N/day, respectively, at 6 µg Se per kg BW. Se intake, blood Se, faecal Se, urine Se and retained Se were negatively correlated with forage crude protein (CP) content (p < 0.001) but were positively correlated with the content of neutral detergent fibre (NDF) (p < 0.001) and acid detergent fibre (ADF) (p < 0.001). Thus, we recommend the addition of 6 µg Se per kg BW to sheep grazed on pastures in regions with low soil Se.

Effects of Allium mongolicum Regel supplementation on the digestibility, methane production, and antioxidant capacity of Simmental calves in northwest China.

This study evaluated the effects of Allium mongolicum Regel (AM) supplementation on nitrogen (N) balance, ruminal fermentation, and antioxidant properties. Sixteen male calves were assigned randomly to four groups, and the four were added with 0 (CON), 200 mg/kg (body weight; BW) (Low AM; LA), 400 mg/kg (BW) (Middle AM; MA), or 800 mg/kg (BW) (High AM; HA) per day for each individual. AM was added on dry matter (DM) basis. The experiment lasted for 58 days. Supplementation of AM could significantly increase average daily gain, DM digestibility, acid detergent fiber digestibility, and retained N/Intake N. N digestibility and molar proportion of propionate in the MA and HA treatments were higher than that in the CON treatment (p < .05), respectively. AM supplementation significantly increased the molar concentration of total volatile fatty acid in the rumen fluid (p < .05). The ratio of acetate to propionate in the MA and HA groups was lower than that in the CON treatment (p < .05). Furthermore, AM supplementation significantly reduced methane (CH4 ) (p < .05) emissions. AM supplementation significantly increased the activities of superoxide dismutase. The MA group could significantly increase the activities of glutathione peroxidase and decrease the content of malondialdehyde. Our results indicated that AM supplementation could affect the nutrient digestibility, CH4 emission, and antioxidant capacity of Simmental calves.