World Aquaculture - December 2014

40 / 76

38 DECEMBER 2014 • WORLD AQUACULTURE •
research has focused on monogastric land-based livestock. Current
publications describe improvements in inflammatory processes
and intestinal health of swine and poultry. For example, a recent
study conducted at the Institute of Animal Nutrition and Nutrition
Physiology at University of Gießen, Germany, investigated the
effects of supplementation with a grape seed and grape marc
meal extract1 on performance characteristics and gut health of
pigs (Gessner et al. 2013). The tested additive might provide a
useful strategy to prevent inflammation in the gut, inasmuch as
different parameters involved in inflammation, such as NF-ĸB,
were improved markedly. Interestingly weight gain increased
by 6.6 percent and feed conversion improved by 4.5 percent. It
needs to be elucidated whether or not these benefits were directly
linked to saving energy and protein, which were no longer needed
for counteracting chronic inflammation. However, it could also
be concluded that the animals were apparently healthy and fed
according to current recommendations.
Available research performed on effects of flavonoids on
aquatic species is scarce but promising. Decaffeinated green tea
extract improves anti-oxidant status and egg quality of rainbow trout
(Asadpour et al. 2012). Malondialdehyde, a marker for oxidative
stress, was lower in trout eggs and related to green tea intake, an
observation that confirmed previous experiments. In fish, reactive
oxidants are produced not only during basal metabolism but can
be generated by cold water temperatures or exposure to the factors
shown in Figure 1. Inasmuch as the anti-oxidant system of the liver is
not activated before late embryonic development, early protection of
eggs via an enhanced anti-oxidant system is of particular importance
to ensure high reproductive performance. Reduced malondialdehyde
content was measured in chicken meat produced from animals fed
on diets supplemented with grape pomace rich in flavonoids.
This transfer of anti-oxidative effects from feed additives
to food products might represent a profitable approach for niche
markets, such as aquaculture caviar production, where the
application of flavonoids might increase the durability of final
products (Fig. 5). However, more information is required and future
research needs to focus on the best flavonoid combinations and
dosages to improve such valuable food products. In this context,
it is crucial to choose the best processing technique of herbal raw
materials. For example, Cho et al. (2007) demonstrated that the
addition of green tea extract to diets of juvenile flounder had better
effects on growth and feed utilization than raw leaves, dry leaves or
a tea by-product.
Conclusions
Future aquaculture will likely face the need to adapt to a
reduced availability of valuable feed ingredients, such as fish
oil, and to improved genetics with faster and more efficiently
growing species. These developments likely will generate a greater
risk of inflammatory damage, which can prevent farmers from
fully exploiting the production potential of their stocks because
controlling inflammation requires energy and protein that will no
longer be available for tissue growth. Secondary plant metabolites,
such as flavonoids, exhibit strong anti-inflammatory properties and
improved anti-oxidant status, production parameters and product
quality of terrestrial livestock and aquatic species. More research
is required to fully understand the underlying mechanisms and
interactions with production factors, such as water temperature and
salinity in different production systems. Feed additives based on
green tea and grape products are available sources of flavonoids
and can contribute to optimized present and future aquafeed
formulations.
Notes
Malte Lohölter, Susanne Kirwan and Bernhard Eckel
Dr. Eckel GmbH, Im Stiefelfeld 10, 56651 Niederzissen, Germany
1 Anta®Ox, Dr. Eckel GmbH, Germany
Corresponding author:
References
Asadpour, R. F., Koochaki Panchah, N. Sheikhzadeh, and H.Tayefi-
Nasrabadi. 2012. Effects of decaffeinated green tea (Camellia
sinensis) on reproductive characteristics and egg quality of
rainbow trout (Onchorhynchus mykiss). Bulgarian Journal of
Veterinary Medicine 15(4):246-253.
Cho, S.H., S.M. Lee, B.H. Park, S.C. Ji, J. Lee, J. Bae and S.Y. Oh.
2007. Effects of dietary inclusion of various sources of green tea
on growth, body composition and blood chemistry of the juvenile
olive flounder, Paralichthys olivaceus. Fish Physiology and
Biochemistry 33:49-57.
Gessner, K.G., A. Fiesel, E. Most, J. Dinges, G. Wen, R. Ringseis and
K. Eder. 2013. Supplementation of a grape seed and grape marc
meal extract decreases activities of the oxidative stress-responsive
transcription factors NF-ĸB and Nrf2 in the duodenal mucosa of
pigs. Acta Veterinaria Scandinavica 55:18-28.
Gjøen, H.M. and H.B. Bentsen. 1997. Past, present, and future of
genetic improvement in salmon aquaculture. Journal of Marine
Science 54:1009-1014.
Gonzalez, R., I. Ballester, R. Lopez-Posadas, M.D. Suarez, A.
Zarzuelo, O. Martinez-Augustin and F. Sanchez de Medina. 2011.
Effects of flavonoids and other polyphenols on inflammation.
Critical Reviews in Food Science and Nutrition 51:331-362.
Pettersson, A. 2010. Effects of replacing fish oil with vegetable
oils in feed for rainbow trout (Oncorhynchus mykiss) and arctic
char (Salvelinus alpinus). Doctoral thesis, Swedish University of
Agricultural Sciences, Uppsala. Sweden.
Ponzoni, R.W., N.H. Nguyen, H.L. Khaw, N. Kamaruzzaman, A.
Hamzah, K.R.A. Bakar and H.Y. Yee. 2008. Genetic improvement
of Nile Tilapia (Oreochromis niloticus) – Present and future.
Proceedings of 8th International Symposium on Tilapia in
Aquaculture 1:33-35.
Sargent, J. R., R.J. Henderson and D.R. Tocher. 1989. The lipids.
Pages 153-218 In J. Halver, editor. Fish nutrition. Academic Press,
New York, New York, USA.
Tacon, A.G.J., M.R. Hasan and M. Metian. 2011. Demand and supply
of feed ingredients for farmed fish and crustaceans – Trends and
prospects. In: FAO Fisheries Technical Paper 564. FAO, Rome,
Italy.
Weiss, U. 2008. Inflammation. Nature 454:427.
Wuerzbach, M., M., Korzekwa, E. Holl and B. Eckel. 2014. Stability
of flavonoids in grape pomace. 13th BOKU Symposium Animal
Nutrition (Proceedings). Vienna, Austria. 226-230