Reduction of confinement stress or adaptation syndrome

The term 'stress', which in English means strain, is used in engineering to define the strain or stress to which materials are subjected. Between 1910 and 1920, Dr. Cannon used the term stress for the first time to indicate an alarming reaction produced in the body by an external stimulus. The Canadian scientist Hans Seyle, in an article published in 1936 pointed out that this alarming reaction is not bound to the type of stressor (stressful agent). He asked himself: why do guinea pigs, regardless of the type of harmful substance inoculated, react by producing the same hormone (cortisol) and show thymus atrophy, thus becoming more vulnerable to infections? (The thymus is a gland situated behind the sternum, inside of which the critical cells of the immune system are developed).

 

 

Seyle concluded that he was facing a fundamental biological response and due to this reason, it's non specific, regardless of the type of stressor, and characterised by the triggering of a vital axis, linked to two endocrine glands (hypophysis and adrenal gland), that was producing a series of symptoms and biological modifications, that could be summarised in the definition of general adaptation syndrome. Therefore, stress represents the adaptation of the body to the change of its internal homoeostasis produced by a stressor. There are three phases described by Seyle:

During the last thirty years, thousands of scientific studies proved that not only guinea pigs but also all animals activate the same fundamental response in the face of a stressful stimulus.

An essential aspect in the adaptation syndrome is represented by the fact that the stimuli are registered by the sense organs and processed by the brain.

The mechanism is the following: an external or internal agent stimulates touch, taste, smell, sight and hearing receptors (one only or, more often, all of them together) and produces a sensation; this sensation is sent to the brain through the nervous system where it is decoded. Once the sensation is identified, perception is elaborated (acknowledgement of the sensation). Once perception is generated (this is a process that only takes a few moments), the body responds to the event: and if it is judged to be stressful, the hypophysis adrenal axis is triggered.

The activation of the hypophysis adrenal axis has been of key importance for the survival of the animals, since it allowed them when facing attacks of hostile nature to respond with utmost rapidity and precision. In case of an attack from a wild animal, the prey reacts in an instant (escaping or defending itself) since the immediate response to stress does not depend on the reason but on the instinct, the limbic system. The deepest stratums of the brain are also the oldest ones and constitute the limbic brain, common to all animals; it is an actual brain inside the brain. The limbic brain constantly receives information from the body through the sense organs and regulates numerous biological functions, such as respiration, heart rate, blood pressure, appetite, libido, hormonal secretion and the immune system.

 

 

In presence of danger (whether real or assumed) in the limbic system where the hypothalamus is situated triggers an adjustment reaction with the consequent activation of part of the autonomic nervous system - the sympathetic nervous system.

This system is responsible for the attack-escape reaction and therefore, in order to prepare the body to fight, it increases the breathing pace and induces the liver to release the stored sugars that provide oxygen and nourishment to the muscles, the heart rate is increased and the blood pressure rises, digestion slows down (because this function is not a priority during the fight), and blood is recalled by the stomach and intestine to flow to the central nervous system and muscles, the reproductive system is blocked and the body finally mobilizes its resources to deal with the danger. It must be underscored that any reaction that occurs as a consequence of a stressor will always be the best option that the body has at that specific time.

The endocrine system participates in the reaction to stress by inducing the pituitary gland, a gland situated in the limbic system, to produce endorphins (which have the purpose of soothing pain) and the adrenal glands to produce adrenalin, noradrenalin and cortisol.

It is essential to understand that stress means life - anything that happens is a source of stress because it modifies the homeostasis and forces the body to adapt.

No animal can withstand a prolonged stress, since sooner or later, adrenal insufficiency will occur, and therefore illness, but in intensive livestock farming, the most damage is caused not only by the lowering of the immune system, but by pecking or cannibalism. All such factors can drastically reduce production performances, thus affecting the mortality and conversion indexes.

Any stressor implies muscular tension and animals are made up of 60 to 80% muscles. Muscular relaxation is required in order to activate the parasympathetic autonomic nervous system that, in contrast to the sympathetic system, slows down the heart rate and breathing pace, it conveys the blood peripherally, spaces out digestion and intestinal motility, and gives a sensation of well-being to the body.

Muscular relaxation allows for the recovery of the exhausted energies very quickly, strengthens the immune system and reduces the presence of cortisol in circulation.

The other important characteristic of muscular relaxation is to soothe the animal and to decrease aggressiveness which can lead to the disappearance of pecking or cannibalism, thus placing the animals in the optimal conditions to express their productive potential.

The use of medicinal plants like Withania Somnifera and Ocimum Sanctum have been used to assess the anti-stress effect by measuring the concentration of plasma cortisol (Figure 3).

 

 

 

 

The activity of these plants is due, in the case of Withania Somnifera, to the presence of flavonoids, (Withanolide A) present in the root and leaves, in the measure of 530 and 520 mg/100 grams respectively on dry weight (Figure 4). With regard to Ocimum Sanctum the main activity is due to the presence of the entire plant of ursolic acid (Figure 5).

In conclusion, the activity of mangifera is linked to the presence of alkaloids, saponins and glucosides that give life to actual precursors of ascorbic acid, thus mitigating the stress overload of adrenal glands.

The pharmacological activity of these flavonoids combined to ursolic acid at peripheral level is mainly anti-oxidant, anti-inflammatory and immunomodulatory. They protect cells from oxidation damage and onset of illnesses, while at a central level acting as a powerful muscle relaxant with a powerful action, an action that unlike other muscle relaxants, occurs without other symptoms like drowsiness and anorexia. This allows animals to continue feeding themselves and triggers a powerful anti-stress activity.

The Figure 6 shows the plasma concentration of antibodies in the presence of stress, proving the efficacy given by the presence of Ocimum Sanctum (Figure 6).

 

 

 

 

The results do not need any further comments to understand the economic benefits of the inclusion in the feed of Withania Somnifera and Ocimum Sanctum. Simply look at the data shown in Tables 1 and 2 that show the results of the experiments carried out on broilers in collaboration with Chennai Veterinary College (India). 

The evidence shows that Withania Somnifera and Ocimum Sanctum possess a powerful anti-stress effect (attenuation of heat stress) and immunomodulatory. 

The use of Withania Somnifera and Ocimum Sanctum in breeders has significantly improved all parameters of economic importance.