Tannins are polyphenols characterized by different molecular weights that plants are able to synthetize during their secondary metabolism. Macromolecules (proteins, structural carbohydrates and starch) can link tannins and their digestion can decrease. Tannins can be classified into two groups: hydrolysable tannins and condensed tannins. Tannins are polyphenols, which can directly or indirectly affect intake and digestion. Their ability to bind molecules and form complexes depends on the structure of polyphenols and on the macromolecule involved. Tannins have long been known to be an “anti-nutritional agent” in monogastric and poultry animals. Using good tannins’ proper application protocols helped the researchers observe positive effects on the intestinal microbial ecosystem, gut health, and animal production. Plant tannins are used as an alternative to in-feed antibiotics, and many factors have been described by researchers which contribute to the variability in their efficiencies. The objective of this study was to review the literature about tannins, their effects and use in ruminant nutrition.

The current study was carried out to evaluate the nutritive value of mushroom-uncultivated and -cultivated substrates, and their in vitro gas and methane production. The experiment was conducted in a completely randomized design, and analyzed with GLM using SAS 9.4. Analysis of the structural morphology of mushroom-cultivated substrate was performed using a scanning electron microscope. Mushroom cultivation led to lower ether extract, acid detergent fiber, and crude fiber level of substrate (p < 0.05). Mushroom-cultivated substrate showed higher in vitro cumulative gas production (p < 0.05). Moreover, mushroom cultivation led to a higher sample surface, and improved the microorganisms’ access to feed materials, thus stimulating rumen fermentation and increasing methane production (p < 0.05). The organic matter digestibility, metabolizable energy, and net energy lactation values were higher for mushroom-cultivated substrate than uncultivated substrate. The results demonstrate that mushroom-cultivation not only increases the contact surface of cellulose, leading to higher ruminal microorganisms’ access to feedstuff, but could also had higher nutritive value; this material might be used in ruminant ration formulation, to reduce environmental pollution and feed costs.

Introduction Grape (Vitis vinifera) is one of the worlds largest fruit crops and grape seeds are usually by-products of processed grape products such as grape juice, grape molasses and wine production. Grape seed is a complex matrix containing

Erzurum ilinde doğal olarak yetişen, akasya (Robinia pseudocacia L), kayın (Fagos adsidue), meşe (Quercus L), salkım söğüt (Salix alba) ve kavak (Populus L) ağaçlarına ait gazel formundaki yaprakların in vitro gaz üretim tekniği ile yem değerlerinin belirlenmesi amacıyla yürütülen çalışmada, in vitro gaz üretim tekniğinde kullanılan rumen sıvısı 2 yaşlı 2 baş İvesi koçtan temin edilmiştir. Kimyasal kompozisyonlarına ait ortalama değerler bakımından ağaç yaprakları arasındaki farklar önemli bulunmuştur (p<0.01). En yüksek HP içeriği ve en düşük NDF, ADF ve ADL değerleri akasya yaprağında saptanmıştır. Mevcut çalışmada, ağaç yapraklarına ait 24 saatlik gaz üretimi, ME, NEL, OMS ve metan üretim değerleri sırasıyla 17.33-31.00 ml/200 mg KM, 4.61- 7.03 MJ/kg KM, 3.18-4.53 MJ/kg KM, %35.43-50.02 ve 2.70-3.01 ml/200 mg KM arasında belirlenmiştir. En yüksek ME, NEL ve OMS ile gaz üretimi değerlerine ve en düşük tanen içeriğine kayın yaprağının sahip olduğu belirlenmiştir. En düşük metan ve in vitro gaz üretimi meşe yaprağında saptanmıştır. Ağaç yapraklarına ait nisbi yem değerlerinin (NYD) 138.88-278.04 arasında değiştiği ve meşe yaprağı hariç incelenen diğer yaprakların en iyi kaliteye sahip oldukları tespit edilmiştir. Sonuç olarak bu çalışamadan elde edilen in vitro verilere dayanarak; yeterli miktar ve kalitede kaba yemin temin edilemediği dönemlerde yüksek kondanse tanen içeriğine sahip olan akasya, söğüt ve kavak yapraklarının kaba yem rasyonlarının belli bir kısmını oluşturabileceği, özellikle kayın yaprağının ruminantların beslenmesi açısından iyi bir alternatif yem kaynağı olabileceği belirlenmiştir Ancak, ruminant hayvan beslemede ağaç yapraklarının gerçek besleyici değerlerini belirlemek için in vitro çalışmaların yanı sıra in vivo çalışmaların da yapılması gerektiği kanaatine varılmıştır.

The chemical composition, in vitro total gas and CH₄ production and performance of cattle fed on factory black tea waste (Camellia sinensis) (BTW), alfalfa (Medicago Sativa), sainfoin (Onobrychis sativa) and white clover (Trifolium repens) was investigated. The gas production was quantified at the 24th hour of the incubation process. BTW was found to vary from roughages in chemical composition (p < 0.05). In addition, the roughages differed in terms of nutrient composition and gas production (p < 0.05). In legume roughages, acetic acid (AA), propionic acid (PA), butyric acid (BA), and total volatile fatty acids (TVFA) values ranged from 52.36–57.00 mmol/L, 13.46–17.20 mmol/L, 9.79–12.43 mmol/L, and 79.71–89.05 mmol/L, respectively. In comparison with black tea waste, legume roughages had higher values of AA, PA, BA, and TVFA. Black tea waste contained a higher acetic acid ratio than legume roughages when compared as a percentage. There was a similar ratio of propionic acid to the rate calculated for sainfoin (Onobrychis sativa) and clover (Trifolium repens), and a similar ratio of butyric acid to the ratio determined for alfalfa (Medicago Sativa). The current study shows that the 5.7–6.3% tannin content of black tea waste can be used in ruminant rations with high-quality roughages. Due to the fact that BTW reduces methane emissions from ruminants and eliminates energy waste from them, the environment can be improved. To obtain more reliable results, further animal feeding experiments on legume roughages and BTW are required.