Effects of Hydrolysable Tannin with or without Condensed Tannin on Alfalfa Silage Fermentation Characteristics and In Vitro Ruminal Methane Production, Fermentation Patterns, and Microbiota

This study was conducted to evaluate the potential of hydrolysable tannin (chestnut tannin, CHT) without or with condensed tannin (quebracho tannin, QT) for modulating alfalfa silage fermentation characteristics and in vitro ruminal methane (CH4) production, fermentation profile, and microbiota. Alfalfa (235 g/kg fresh weight) was ensiled with no tannins (control), 2% CHT (CHT2), 5% CHT (CHT5), the combination of CHT and QT at 1% each (CHQ2), and CHT and QT at 2.5% each (CHQ5) of forage dry matter (DM). The CHQ2 treatment was more effective in reducing DM losses, pH, and ammonia–nitrogen to total nitrogen ratios of alfalfa silage than CHT2 and CHT5 treatments. All tannin treatments decreased ruminal CH4 production, and the magnitude of the decrease was greater for the combinations than the individual ones. Total volatile fatty acid (VFA) concentrations and DM degradation decreased by tannin treatments, but microbial protein (MCP) synthesis increased. The total VFA concentrations and DM degradation were lower with CHQ2 treatment than with CHT5 and CHQ5 treatments, but the MCP concentrations were comparable among these treatments. Tannin inclusion decreased the abundance of the anaerobic fungi Ruminococcus albus and Ruminococcus flavefaciens, but enhanced Fibrobacter succinogenes. The combination of CHT and QT alleviated the inhibition of CHT supply alone in Butyrivibrio fibrisolvens, Ruminobacer amylophilus, and Prevotella ruminicola as well as protease. The results revealed that a combination of HT from CHT and CT from QT at a low level can reduce proteolysis and CH4 production of alfalfa silage without impairing ruminal fermentation and microbiota.

Barricyclin D1—a dimeric ellagitannin with a macrocyclic structure—and accompanying tannins from Barringtonia racemosa

Our examination of high molecular weight polyphenolic constituents in the leaves of Barringtonia racemosa of the family Lecythidaceae uncovered five previously undescribed ellagitannins. One, barringtin M1 (1), among them was a hydrolysable tannin monomer, while remaining four, barringtins D1 (2), D2 (3), D3 (4) and barricyclin D1 (5), were all dimers. Barricyclin D1 had a first macrocyclic structure formed from casuarictin (6) and tellimagrandin I (7), and the other ellagitannins had structures related to 5. Two additional known phenolics, valoneic acid dilactone (8) and schimawalin A (9), were also isolated from the leaves. These results suggested that the leaves of B. racemosa is a natural resource rich in hydrolysable tannin oligomers.

Effect of hydrolysable tannin on nutrient intake obesity and other associated metabolic risk factors in polycystic rats

Background Food intake and eating behavior are two important risk factors that lead to obesity and other associated metabolic and reproductive disorders like polycystic ovarian syndrome (PCOS). Most of the phytonutrients like hydrolysable tannin (HT) have the ability to reduce the nutrient intake that might be a suitable remedy for weight management of females in their reproductive age. Therefore, the present research is aimed to find out the effect of HT on nutrient intake, weekly body weight, blood glucose, serum lipids, minerals, immunoglobulins and satiety hormones in PCOS rats. Materials and methods A total of forty five adult healthy female rats of 56 days old, weighed 135 ± 5 g with two consecutive estrous cycles were selected. In order to induce PCOS in rats, the intramuscular injection of 4 mg/rat/kg Estradiol- Valerate was used. After induction, a Complete Randomized Design was used to divide the rats into five equal groups (n = 9) named as Pc0, Pc0.5, Pc1, Pc1.5 and Pc2. The groups of rats were offered different doses of HT i.e. 0, 0.5, 1, 1.5 and 2 % respectively per kg body weight in solution form through oral gavage once in a day for 60 days. Results After the intake of different levels of HT, the statistical results had shown a significant decrease (p < 0.05) in the weekly nutrient intake, body weight, water intake, weight gain, fasting blood glucose in PCOS rats. A similar trend of decrease (p < 0.05) was noticed in serum iron, IgM, IgG, leptin, ghrelin, cholesterol, low density lipoprotein and triglycerides while a significant improvement (p < 0.05) was also observed in high density lipoprotein in the PCOS rats. However, a non-significant effect (p > 0.05) was observed on serum protein and calcium levels. Conclusions The study concluded that HT had a therapeutical potential to decrease the nutrient intake and its anti-nutritional property could be used as remedy for the management of body weight, hyperglycemia, dyslipidemia and cardiovascular risk factors of PCOS rats.

Fatty acids in rumen and meat of lambs fed with different condensed and hydrolysable tannin extracts

Five groups of lambs (n = 9 each) were used to test the effect of plant extracts rich in hydrolysable (HT) or condensed tannin (CT) on animal performance, fatty acid composition of rumen content and meat. The control group (CO) received a concentrate-based diet without tannins supplementation. The other groups received the same diet as the control lambs plus 4% chestnut (CH) and tara (TA) extracts as a source of HT and mimosa (MI) and gambier (GA) extracts as a source of CT. Dietary CH negatively affected animal performance. The rumen content of the different groups showed comparable levels of 18:3 c9c12c15, 18:2 c9c12, 18:2 c9t11, 18:1 t11 and 18:0, whereas 18:1 t10 was greater in CO. Also, 18:1 t10 tended to be lower in the rumen of HT than CT-fed lambs. These data were partially confirmed in meat, where CO showed a greater percentage of individual trans 18:1 fatty acids in comparison with tannins-fed groups. Our findings challenge some accepted generalizations on the use of tannins in ruminant diets as they were ineffective to favour the accumulation of dietary PUFA or healthy fatty acids of biohydrogenation origin in the rumen content and lamb meat, but suggest a general action of tannins on the whole biohydrogenation process.