Probiotics and Prebiotics: Concepts, Definitions and History - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 172

(Gatesoupe 1999; Gram and Ringø 2005; Lauzon 2010; Merrifield et al . 2010; Nayak 2010;
Prado et al . 2010; Dimitroglou et al . 2011). The application of probiotics in aquaculture has
been related to several beneficial effects, namely modulation of the intestinal microbiota and
immune system, as well as enhanced survival, development, nutrition and disease resistance.
However, further research is required to establish their exact modes of action (Tinh et al .
2008; Nayak 2010).
7.2.1 Etymology of 'probiotic' and its definitions
The term probiotic is composed of the preposition pro , meaning 'for' in Latin or 'in front
of/before' in Greek, and biotic , a Greek adjective relating to the noun bios meaning 'life'.
While the overall meaning implies that it favours life, 'for life', it could also suggest that a
probiotic is a compound that becomes activated in situ to support life and enhance vitality.
This etymology of the term probiotic is reflected by the different definitions proposed through
the years, which were based on the understanding of mechanisms and sites of action, delivery
forms and methods as well as the hosts treated.
To our knowledge, the term probiotic(s) was first mentioned by Kollath (1953), defined
as organic and inorganic supplements required to restore the health of malnourished patients.
These supplements were considered common in vegetable food as vitamins, aromatic sub-
stances, enzymes or possibly other substances connected with vital metabolic processes. The
latter included bacteria and their constituents delivered via vegetables (Rusch 2002). This is
perhaps the first allusion made to the indirect use of microorganisms as probiotics. Vergin
(1954) then proposed that the use of a probiotic diet, including fermentation products, could
contribute to the microbial balance of the body otherwise disturbed following an antibiotic
treatment. Kolb (1955) supported this suggestion which in some way approaches the defini-
tion accepted today. Later, Lilly and Stillwell (1965) defined probiotics as growth-promoting
factors produced by microorganisms.
After the denotation of action towards vital processes, microbial balance and growth stimu-
lation of the host (or its indigenous gut microorganisms), the potential of probiotics to modulate
the host immune response was proposed by Fujii and Cook (1973), who defined probiotics
as 'compounds that build resistance to infection in the host but do not inhibit the growth of
microorganisms in vitro '. So at that time, probiotics were considered as compounds and/or
microorganisms with different functions contributing to health restoration, maintenance or
enhancement through routes not related to microbial antagonism or competition. In 1974,
Parker refined the definition of probiotics as acting towards the digestive tract: 'organisms
and substances which contribute to intestinal microbial balance'. This may be considered as
the first direct mention of probiotics in the context of gut health, though Vergin (1954) may
have suggested the action of the probiotic diet towards the intestinal microbiota in describing
'the microbial balance of the body'. Fuller (1989) also focused on the intestinal microbial bal-
ance in his definition, but he further emphasized the notion of the viability of probiotics and
their health enhancing effect in animals with the definition of 'live microbial feed supplement
which beneficially affects the host animal by improving its intestinal microbial balance'. The
imprecision of Parker's (1974) definition would otherwise have included antibiotics.
Later, the definition was broadened by Havenaaer and Huis in't Veld (1992) with respect to
host and habitat of the microbial flora: 'viable mono- or mixed culture of microorganisms,
which applied to animal or man, beneficially affects the host by improving the properties
of the indigenous microbiota'. This allowed for the effects of probiotics on other organs or