Issues with Industrial Probiotic Scale-up - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 352

Potential probiotics for aquaculture application produced solely at the small scale laboratory
level do not always demonstrate reproducible efficacy at industrial level. For example, LAB
produced at laboratory level, then dried and suspended in buffer prior to use, may not nec-
essarily reproduce similar growth and/or viability at industrial level. This basic preparation
procedure is far from the required procedure for the industrial scale production. Unfortunately
there appear to be very few studies that have paid sufficient attention to the optimization of
culture conditions for industrial application (Ochoa-Solano and Olmos-Soto 2006). Probiotics
are live (viable) microorganisms and thus differ from chemical substances and must be man-
aged differently. Their efficacy depends not only on the strain of microorganism, but also on
its physiological state. The latter is crucial in relation to viability, stability and efficacy/activity
at the application stage.
Few studies have compared the effect of a microorganism administered to fish as either
viable or killed (non-viable) microorganisms, but it has been demonstrated that viability is an
important factor with regards to probiotic efficacy for fish (Brunt and Austin 2005; Panigrahi
etal. 2005; Taoka etal. 2006). Panigrahi etal . (2005) concluded that even though the potential
benefits of heat-killed cells should not be overlooked, viable forms induced better and possibly
reproducible results. Also microorganisms, as isthe case with all living organisms, are selective
in terms of benefits they could exert and their modes of action; hence not all probiotics are
equivalent in the way they act and the ultimate benefit they exert.
A recent study evaluated 12 different commercial probiotics marketed for use in marine
shrimp production in Thailand (Nimrat and Vuthiphandchai 2011). Starting from their presen-
tation for sale, only two products provided the necessary information on the label as to the
strain names of the live microorganisms or the recommended dose for their use. That notwith-
standing, none of the 12 products provided the composition or number of cells of the strains
indicated on the label. There were also huge discrepancies with regards to matching the strains
in the products to those indicated on the labels (Nimrat and Vuthiphandchai 2011).
The viability of yeast and bacteria depends on the strain's intrinsic and extrinsic properties,
although this is often overlooked, and on the quality of the production process, formulation
and storage conditions. The production of live bacteria requires expertise and stringent quality
controls throughout the process, and only a few companies in the world actually possess the
technical knowhow and industrial capability to produce and process the live microorganism in
a way that ensures that it is and/or does what it says on the label, and that it is stable with a
consistent performance.
If we take the example of bacterial production, several hundred tonnes of products contain-
ing hundreds of billions of live bacteria per gram are produced each year. However, production
always starts with a few microlitres of the stored cell suspension in a vial at a collection bank.
This tiny amount of live bacteria undergoes sequential multiplications in strictly controlled
conditions, first in small scale flasks and successively in larger industrial scale fermentors
(where the final volume could be as large as 10 cubic metres or more). During this process it
is difficult to maintain the strain's integrity without stringent quality control measures at each
step. For example, any contaminant or changes in growth conditions could irrevocably affect
the bacteria's behaviour and physiology, ranging from changes in the purity of the strain to
effects on its activity, viability and efficacy. At each step in the production process, it is imper-
ative that the bacteria's identity, purity and activity are controlled by appropriate testing. These
checks ensure that the end-product is safe and efficacious.