Aqua Culture Asia Pacific May/June 2021 issue

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54 Feed Technology COMP 1

COMP 2

CeFi Pro

+ 6.7 %

+ 0.3 %

+ 8.2 %

Weight gain ratio + 10.9 %

+ 1.6 %

+ 11.3 %

Specific growth rate

+ 4.7 %

+ 0.6 %

+ 4.7 %

Feed conversion ratio

- 5.6 %

+ 0.6 %

- 6.9 %

Final body weight

Table 1. Relative differences (%) in growth performance and feed conversion ratio of shrimp fed with the experimental diets vs the control diet for 8 weeks (n =4).

scale production processes, CeFi Pro comes from a highquality, food-grade production process with clean, clearly defined and GMO-free raw materials of the brewing industry. Therefore, its continuously high quality level can be guaranteed. Furthermore, the lysis process applied to the above mentioned yeast cell wall degradation (acid hydrolysis or enzymatic autolysis) can also influence the amount of free amino acid content and the molecular weight of peptides in the lysed yeast products (Podpora et al., 2015). An acid hydrolysis process has high overall production yields and is relatively more convenient for mass scale production, as compared to enzymatic autolysis with lower extraction yields and highest purity. Furthermore, acid hydrolysis leads to a high probability for the presence of carcinogenic compounds (monochloropropanol and dichloropropanol) and to relatively high salt contents (Podpora et al., 2016). In contrast, Leiber’s CeFi Pro, being processed under superior enzymatic autolysis conditions is able to offer a high quality source of free amino acids, nucleotides and nucleosides, vitamins, trace elements and high levels of peptides with low molecular weight. In species with a short and complex digestive tract such as shrimp (Ceccaldi, 1989), a high bioavailability of these valuable nutrients is very useful and the nutrients will be readily absorbed through the enterocytes along the alimentary tract. This potentially explains the better growth performance observed. In addition, the substrate on which the yeast cells are grown might be of significant importance to the nutritional composition of the final product. As Podpora et al. (2015) described, also the wort/slurry remaining from the brewing process, in which the yeast cells are suspended, is rich in proteins, peptides and free amino acids derived from barley and other components used in beer production. Yeast products derived from other substrates may be less rich and complex in nutritional composition. In this context, also the hops used during beer production is contributing beneficial antioxidative and bacteriostatic effects through a range of bioactive constituents (polyphenols, flavonoids, etc.) to the final product (Leiber GmbH, internal communication, 2009). Yeast products fermented on other substrates do not possess this feature.

Conclusion

Better performance of the autolysed Leiber CeFi Pro at the same dosage as the two other commercially available hydrolysed yeast products in the present study proves that production processes influence the product efficiency. Many factors – especially the fermentation substrate used, the lysis method, separation of cell walls from cell contents, May/June 2021 AQUA Culture Asia Pacific

nutritional concentration and composition of the final lysed yeast, etc. – will eventually impact the performance of the end product. Autolysed brewers’ yeast CeFi Pro, is high in natural DNA and RNA components with free nucleotides and nucleosides, present in highly digestible free amino acids, and in short-chain peptides. It is recommended for use in aquaculture species at 0.2-0.3% in a complete feed. Remarkably, when it was added to feed, the inclusion of other feed additives for immune boosting and attractability/palatability can be reduced or removed completely. This is due to the fact that Leiber’s CeFi Pro also contains yeast cell walls consisting of both ß-glucans and mannan oligosaccharides (immune enhancers) and nucleotides (palatant and attractant), respectively. Overall, this product contributes to the economic benefit to the feed industry with added value. References Ceccaldi, H.J. 1989. Anatomy and physiology of digestive tract of crustaceans decapods reared in aquaculture. In: Advances in tropical aquaculture Tahiti, Aquacop. Ifremer. Actes de Colloque 9: 243-259. Ferreira, I.M.P.L.V.O., Pinho, O., Vieira, E. and Tavarela, J.G. 2010. Brewer’s Saccharomyces yeast biomass: characteristics and potential applications. Trends in Food Science & Technology 21: 77-84. Leiber GmbH, internal communication. 2009. Bacteriostatic effect of brewers’ yeast. Nasseri, A.T., Rasoul-Amini, S., Morowvat, M.H. and Ghasemi, Y. 2011. Single cell protein: Production and process. American Journal of Food Technology 6: 103-116. Podpora, B., Świderski, F., Sadowska, A., Piotrowska, A. and Rakowska, R. 2015. Spent brewer’s yeast autolysates as a new and valuable component of functional food and dietary supplements. Journal of Food Processing and Technology 6: 526. Podpora, B., Świderski, F., Sadowska, A., Rakowska, R., and Wasiak-Zys, G. 2016. Spent brewer’s yeast extracts as a new component of functional food. Czech Journal of Food Science 34: 554–563. Rumsey, G.L., Hughes, S.G., Smith, R.R., Kinsella, J.E. and Shetty, K.J. 1991a. Digestibility and energy values of intact, disrupted and extracts from brewer’s dried yeast fed to rainbow trout (Oncorhynchus mykiss). Animal Feed Science and Technology 33: 185-193. Rumsey, G.L., Kinsella, J.E., Shetty, K.J. and Hughes, S.G. 1991b. Effect of high dietary concentrations of brewer’s dried yeast on growth performance and liver uricase in rainbow trout (Oncorhynchus mykiss). Animal Feed Science and Technology 33: 177-183. Shurson, G.C. 2018. Yeast and yeast derivatives in feed additives and ingredients: Sources, characteristics, animal responses, and quantification methods. Animal Feed Science and Technology 235: 60-76.

Dr Holger Kühlwein is Key Account Manager Aquaculture, Leiber GmbH, Bramsche, Germany. Email: h.kuehlwein@leibergmbh.de Dr Pradeep P. J. is Regional Sales Coordinator, Leiber GmbH, in Asia Pacific Region. Email: pradeep@leibergmbh.de