Luminal Nutrition is a term used in gastrointestinal phyology and defined as the growth of the mucosa associated with the presence of nutrients in the intestinal lumen.

In fact, the intestine responds directly to the presence or absence of nutrients by either growing or becoming atrophied.

The best model for determining this concept is total parenteral nutrition (TPN) where all nutrients are supplied intravenously.

Studies using the TPN model have shown that the absence of nutrients in the intestine over a period of two days results in partial desquamation of the epithelium of the intestinal mucosa, whereas after five days even the integrity of the mucosa is lost, increasing the risk of bacterial translocation, thus proving the importance of the presence of nutrients in the intestine.

There are also many problems associated with the transition from parenteral nutrition to oral nutrition and, as such, the most recent research has been aimed at determining how to help improve recovery of the intestine to enable gentler transition from parenteral to oral nutrition.

The practical application of this problem in farm animals is basically concentrated in periods of low or no intake of food due to productive or pathological stress, or whenever this occurs naturally at certain growth stages of the animals.

There are various methods of resolving low or no food consumption. These are basically divided into two large groups:

· Stimulation of food consumption by making the more appetising.

· The inclusion of intestinal mucosatrophic nutrients which make it possible for intestinal atrophy to be reversed when food intake resumes.

The first groups includes products such as aromas, sweeteners and some protein ingredients such as hydrolysed protein or porcine plasma; whereas the second group includes nutrients such as nucleotides or their metabolic precursor, glutamine, Finally there is a group of products  that do not act directly on the intestinal mucosa but on its associated immune system. These products include probiotics, betaglucans and some polyunsaturated fatty acids.

With this short introduction we have attempted to give a brief summary of the basic subject matter dealt with in this publication, in an attempt to promote a stronger relationship between nutrition and physiology.