Plant physiology Julius von Sachs unified the pieces of plant physiology and put them together as a discipline. His "Lehrbuch der Botanik" was the plant physiology bible of its time. Researchers discovered in the 1800s that plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil are dissolved in water, plant roots absorb nutrients readily, soil is no longer required for the plant to thrive. This observation is the basis for hydroponics, the growing of
Natural growth promoter and quebracho ("Schinopsis lorentzii", condensed tannins) extracts, are effective to reduce and control infection. Moreover are considered a natural alternative to AGPs due to the difficulty of bacteria to develop resistance against the diverse range of molecules that contain these plant compounds. Animal feeds contain varying levels of indigestible nutrients and undesired components such as fiber, phytate or proteins with antigenic effects. Different feed enzymes such as, carbohydrases, phytases or proteases, can be included in feeds to improve the utilization of energy and nutrients or to degrade several undesired components. Moreover, some enzymes (e.g. amylases, lipases) can be added to