Probiotics are defined as live microorganisms which can confer a health benefit for the host when administered in appropriate and regular quantities. Once ingested, the probiotic microorganisms can modulate the balance and activities of the gastrointestinal microbiota, whose role is fundamental to gut homeostasis. It has been demonstrated that numerous factors, such as dietary and management constraints, can strongly affect the structure and activities of the gut microbial communities, leading to impaired health and performance in livestock animals.
Growthpromoting antimicrobials, such as ionophore antibiotics, have been widely distributed and are still used in some countries. However, due to increasing safety concerns about the risk of releasing antibiotic resistance in the environment, and the persistence of chemical residues in animal products, other strategies based on supplementation of more ‘natural’ products such as probiotics, have been developed to improve herd health and productivity. Probiotics are defined as a source of live (viable) naturally occurring microorganisms, can beneficially affect the balance of GIT microbiota and that they have a real benefit in animal nutrition and health.
Here is some important benefits of yeast and bacterial probiotics upon the gastrointestinal microbial ecosystem in ruminants and monogastric animals (equines, pigs, poultry, fish).
The most significant effects of probiotics have been reported when they have been included in the diet of animals during particularly stressful periods for the gut microbiota and the animal: at weaning; at the beginning of the lactation period; and after a dietary shift from high forage to high readily fermentable carbohydrates.
Benefits of probiotics in ruminants
+ Promoting optimal maturation of the rumen microbiota.
+ Increasing digestive safety at weaning.
+ Reducing risk of pathogen colonisation.
+ Increasing milk yield and quality.
+ Increasing feed efficiency.
+ Promoting health (limit acidosis).
+ Promoting weight gain.
+ Increasing feed efficiency.
+ Promoting health (reduce acidosis).
+ Limiting shedding of human pathogens.
Benefits of probiotics in equines
+ Increase diet digestibility.
+ Improve milk quantity and quality.
+ Promote growth.
+ Limit diarrhoea
+ Avoid hindgut disorders (acidosis, colic) and increase digestibility of diet.
+ Limit stress (transportation, race, etc.)
Benefits of probiotics in pigs
+ Improve diet digestibility.
+ Limit constipation.
+ Decrease stress.
-Lactating sow and piglets:
+ Improve colostrum quality, milk quality and quantity.
+ Increase litter size and vitality.
+ Increase piglet weight.
+ Reduce risk of diarrhoea.
+ Improve feed efficiency.
+ Improve meat quality.
+ Reduce risk of diarrhoea
In poultry, benefits of probiotic supplementation (live yeast or bacteria) increase resistance of chickens to Salmonella, E. coli or C. perfringens infections. Probiotics also can increase feed efficiency and productivity of laying hens, and an improvement in egg quality (decreased yolk cholesterol level, improved shell thickness, egg weight).
In aquaculture, growth-promoting effects, through better feed utilisation and digestion, as well as biological control of pathogen colonisation are the most important expected benefits of probiotic applications. Under pond conditions, the distribution of a P. acidilactici-based probiotic could be an effective treatment for limiting prevalence and load of Vibrio nigripulchritudo strains in haemolymph of marine shrimps. Some probiotics have been shown to protect rainbow trout against skin infections caused by Aeromonas bestiarum and a eukaryotic pathogen, Ichthyophthirius multifiliis.
According to F. Chaucheyras-Durand and H. Durand