Effects of dietary supplementing tannic acid in the ration of beef cattle on rumen fermentation, methane emission, microbial flora and nutrient digestibility.

Four adult Simmental male cattle (376 ± 9.0 kg initial BW), fitted with permanent rumen cannulas, were used in a 4 × 4 Latin square design to investigate the effects of dietary supplementing tannic acid (TA) on rumen fermentation, methane (CH4 ) production, rumen microbes, nutrient digestibility and plasma biochemical parameters. Four levels of TA, that is 0, 6.5, 13.0 or 26.0 g/kg dry matter (DM), were added to the basal ration (composed of corn silage and concentrate mixture) as experimental treatments respectively. Each experimental period consisted of a 12-day adaptation phase followed by a 3-day sampling phase. The results showed that supplementing TA at 26.0 g/kg DM decreased the relative abundance of protozoa, methanogens and Ruminococcus albus to the total ruminal bacterial 16S rDNA in beef cattle (p < 0.05). The results also showed that supplementing TA at 6.5, 13.0 or 26.0 g/kg DM decreased (p < 0.01) the CH4 production (l/kg DM intake) by 11.1%, 14.7% and 33.6% respectively. Supplementing TA at 13.0 or 26.0 g/kg DM decreased the ratio of acetate to propionate and ammonia nitrogen (NH3 -N) (p < 0.05) and tended to decrease the total volatile fatty acid (VFA) concentration of rumen fluid (p = 0.07). Supplementing TA at 26.0 g/kg DM decreased DM and organic matter (OM) digestibility (p < 0.05), supplementing TA at 6.5, 13.0 or 26.0 g/kg DM decreased (p < 0.01) crude protein (CP) digestibility by 5.0%, 8.6% and 15.7%, respectively, and supplementing TA at 6.5, 13.0 or 26.0 g/kg DM increased (p < 0.05) the plasma total antioxidant capability. It was concluded that supplementing TA in the ration of beef cattle decreased the CH4 production and digestibility of CP of beef cattle. Supplementing TA could be an effective option to mitigate CH4 emission form cattle, further research is necessary to study the effects of TA on the performance of cattle.

Age-related changes and nutritional regulation of myosin heavy-chain composition in longissimus dorsi of commercial pigs.

The objective of this study is to investigate the age-related changes of and the effects of dietary conjugated linoleic acid (CLA) on muscle-fibre types in commercial pigs. We divided 25 crossbred male pigs into five age groups (7, 30, 60, 100 and 180 days) and 30 finishing pigs into two dietary groups (one fed a CLA-enriched diet and the other fed a control diet for 30 days). We analysed the composition (%) of myosin heavy-chain (MyHC) mRNA according to the absolute copies of each MyHC (I, IIa, IIb and IIx) mRNA, and the activities of succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) in the longissimus muscle. From days 7 to 180, the MyHC I mRNA abundance and SDH and MDH activities presented a decreasing trend, the MyHC IIb mRNA abundance presented a steady trend and the MyHC IIa and IIx mRNA abundances presented an increasing trend. On day 30, MyHC I and IIb mRNA abundances were at their lowest (P < 0.05), and the MyHC IIa and IIx mRNA abundances were at their highest (P < 0.05). In the CLA group, the MyHC I mRNA abundance and the activities of SDH and MDH were improved in the longissimus muscle, whereas pressure loss, drip loss and average back fat depth significantly decreased (P < 0.01) and shear force significantly increased (P < 0.01). Loin eye area, feed conversion rate and meat colour showed some tendency to be improved. These results indicated that more oxidative fibres might convert to glycolytic fibres with increasing age or weight, and that the early developmental stage might be a key stage for this conversion. During the finishing stage, the proportion of oxidative fibres might be increased by dietary CLA supplementation, which may contribute to the water-holding capacity of meat. The results would provide an important basis for the application of muscle-fibre types in the improvement of pork quality.

Flavonol glycosides from Epimedium sagittatum and their neurite outgrowth activity on PC12h cells.

The MeOH extract of Epimedium sagittatum was found to show neurite outgrowth activity on cultured PC12h cells. Bioassay-guided fractionation of the MeOH extract yielded six prenylated flavonol glycosides, ikarisoside A (1), icarisid II (2), epimedoside A (3), icariin (4), epimedin B (5), and epimedokoreanoside-I (6) as the active ingredients.