Page 45 - New additives and ingredients in the formulation of aquafeeds

The drastic effects of the phytobiotic product on survival may be related to
the fact that this study was performed during the worst farming cycle of
the year in Panama, when shrimp ponds are exposed to severe transitional
changes in weather at the end of the wet season and the beginning of the
dry season. Natural White Spot Disease outbreaks were observed during
shrimp farming in both treatments under similar frequency and severity;
WSSV virus was confirmed by immuno-chromatography and nested-PCR
tests. The presence of a synergistic blend of phytobiotics with antimicrobial
activity, possibly protected the shrimp from co-infections with opportunistic
bacteria, often the major cause of mortality in WSSV-infected shrimp.
Higher crop yield per hectare due to better survival often results in slower
growth due to reduced availability of natural food. Despite significantly
higher survival and crop yield, a positive effect was observed of phytobiotics
on growth rate and food conversion. This confirmed that the continuous
dosing of natural antimicrobial activity in the feed results in beneficial
physiological effects from stabilizing the microflora present in the digestive
system.
Conclusion Current aquafeed formulations are mainly focused on nutritional
specifications and ingredient choice. The optimal utilization of the nutrients
by the fish and shrimp and the health status of the digestive tract are two
areas still under development in aquaculture. This is in strong contrast with
the vast progress made in the agrifeed sector, where nutrient digestibility
and gut health are regarded as two focus areas for technological feed
development. The current paper illustrated with lab and field studies the
potential benefits for aquaculture in terms of productivity and economics
of specific feed additives developed to enhance the functioning of the
digestive tract, either by improving the nutrient utilization or by stimulating
the development of a healthy gut microflora.
Innovative approaches to reduce feed cost in aquaculture: optimizing nutrient utilization and gut health 43