**Usefulness:**


**Possible outcome:** Research outcome will help identify tannins and other phytochemicals which can be used as silage additives. Tannins shift N excretion from urine to feces and from soluble to insoluble N forms in feces. This undigested form of N from plant residues mineralizes more slowly than microbial and endogenous N, and these shifts in N forms could reduce ammonia and nitrate losses from ruminant production system and thus contribute to reducing the protein and NPN supplements in the animal feed. Besides improving N usage and aerobic stability of silages, the ingested phytochemicals also have significant role on improving ruminant livestock products and their shelf life [18]. This will augment "Green Consumerism" and the naturally improved products could be placed on the market at higher prices with the brand name of "environment-friendly products." Ultimately, farmers will feel encouraged to adopt bioactive forage-enriched feed for livestock feeding.

#### *3.3.2. Use of phytochemical-rich plants and nutrient usage*

The use of phytochemicals in ruminants can induce beneficial effects, most-importantly, the role of condensed tannins on retention of dietary N (reduced urinary output) and its overall usage vis-à-vis efficiency of energy utilization. Ensiling of N-rich forages (e.g. alfalfa/lucerne, berseem, cowpea, etc.) transformed majority of protein N into non-protein N (NPN), which can be inhibited to some degree by accelerating the rate of pH decline during silage fermentation, but compared to cereal forages, structural difference in leaf: stem ratio and its physicochemical characteristics, low WSC content and high buffering capacity make it difficult to ensile resulting in proteolysis. Forages containing condensed tannins (CT) undergo less proteolysis during ensiling, and transformation of their plant protein N into NPN is inhibited compared to forages without CT [10, 19, 20]. Therefore, adding tannins during ensiling holds key both at ensiling and at ruminal level to check N degradation and decrease its excretion to the environment. High level of tannins may adversely affect the activities of silage bacteria [21]. Co-ensiling sainfoin and alfalfa improves fermentation in silos and increases total tract digestibility, suggesting positive associative effects of the two forages [20]. The optimal ensiling and ruminal fermentation for alfalfa and sainfoin were observed at approximately 60:40 ratio (DM basis). It also reduces proteolysis and preserves the nutritive value with sainfoin relative to alfalfa alone. Both total phenol and total tannin contents contributed to the decrease in lactic acid production. Fasuyi et al. [22] found 4% molasses and 14 to 21 days ensiling period optimum and most suitable for effective ensiling of *Tithonia diversifolia* leaves. They also observed a gradual decrease in major anti-nutrients (phytin, tannins, oxalates, alkaloids, flavonoids) with lengthening duration of ensiling. However, there are reports that tannins suppress the production of lactic acid during ensilage [23]. A number of additives that include chemical inhibitors, such as acids, formaldehydes, and various salts, and biological stimulants (LAB and other bacteria) expedite lactic acid production to support ensiling process [24]. The resistance mechanisms of *L. plantarum* include the ability to degrade phenolic compounds [25] such as tannin, by the action of novel tannin acylhydrolase [26] and gallate decarboxylase enzymes [27].
