Taken from “Prebiotic activity of garlic (Allium sativum) extract on Lactobacillus acidophilus” which was published on 12th 2019 in the journal of VET WORLD.
Antibiotics have been used in the broiler farm industry for decades. Regarding the issue of food security, antibiotic growth promoters (AGPs) are used in most countries . This is related to the potential of AGPs to cause resistance in humans as consumers . Because the ban on AGPs can have a negative impact on the health and productivity of chickens, an alternative substitute for AGPs is needed.
Prebiotics are substrates or undigested food  that are selectively fermented by several microflora that live in the digestive tract, such as Lactobacillus and Bifidobacterium, which has a beneficial effect on health . Prebiotics function to stimulate the growth and activity of bacteria that have beneficial effects on the health of the host, especially non-pathogenic bacteria. Gilchrist et al.  reported that almost every oligo- and polysaccharide is a prebiotic, but not all carbohydrate foods are prebiotic. According to Kareem et al. , there are at least three criteria that need to be fulfilled by a material so that it categorized as prebiotic; (1) it cannot be hydrolyzed nor absorbed at the top of the gastrointestinal tract so that it can reach the colon without structural changes and not be excreted in the feces ; (2) it must be selected and fermented by a number of beneficial microflora in the colon to produce a beneficial effect on the host and stimulate the growth of bacteria that actively carry out metabolism ; (3) it must be able to convert the colon microflora into compositions that benefit health and selectively stimulate the growth activity of bacteria, such as Lactobacillus in the colon .
Allicin and other sulfur components in garlic are active ingredients with antibacterial effects . Garlic has an antibacterial activity that is quite effective at fighting various kinds of Gram-negative and/or positive bacteria . Some bacteria that have been shown to have a high sensitivity to the antibacterial activity of garlic are Staphylococcus, Mycobacteria, and Proteus species . Studies have reported that garlic can be used as a natural prebiotic in feed at a level of 1.0% to improve growth performance .
However, studies on the use of garlic as a synbiotic with Lactobacillus acidophilus are still limited. This research aimed to examine the effect of optimal prebiotic concentration in increasing the growth of probiotic bacteria in vitro.
For the addition of garlic as a prebiotic with L. acidophilus, which can be used as a synbiotic, 4 ml of extract is the most effective at increasing the growth of L. acidophilus, acid and bile salt resistance, feed viability, temperature resistance, and feed storage time.