Trace element sustainability needs smaller environmental footprint
Over 200 delegates attended the inaugural OTEANE (Organic Trace Elements
for Animal Nutrition and the Environment) Symposium held earlier this year at
the Geneva Portes Sud Convention Centre. Sponsored by Pancosma and chaired by
Dr. Age Jongbloed from Wageningen UR, Netherlands, the symposium brought together
scientists from all over the world to debate the environmental and nutritional
consequences of the increasing use of trace element supplements in intensive livestock
production systems.
Opening the discussion, Frans Verstraete from the European Commission, made it
clear that the Commission's intention was to reduce maximum permitted levels of
legitimate trace elements and contaminants in animal feeds, thereby reducing environmental
accumulation.
Animal nutrition needs to become aligned closely with soil science for the use
of trace element supplements, in particular copper and zinc, to be sustainable
in the long term. That was the keynote message emerging from the two-day, 20-speaker
symposium.
In order to minimise the future accumulation in soils of excess copper and zinc
excreted from animal production, speakers identified four specific issues for
attention; Replacing low grade chemical supplements with high bioavailability
organic complexes; applying scientifically-sound protocols for assessing bioavailability
to replace incorrect data based on outdated methods; more accurate knowledge of
animal requirements; and the elimination of ‘just-in-case’ safety margins in setting
trace element supplement levels.
From Berlin University, Professor Klaus Männer presented results from a trial
in weaned pigs showing 22 and 47 per cent higher bioavailability of zinc and copper
glycinates than their sulphate salts. Professor Jerry Spears from North Carolina
State University emphasised the importance of assessing bioavailability values
under deficient rather than surplus supply in the test animals.
Professor Gretchen Hill from Michigan State University said long-standing over-supplementation
of copper, zinc, iron and manganese in US pig production had not only led to high
levels of these trace elements being released into the environment in manures,
but had also conditioned the mindset of producers to expect such high levels “as
a kind of purchase protection insurance policy”. She also made the case for new
research into genetic differences in trace element retention between different
breeds and strains of pig.
Then Professor Wilhelm Windisch of Vienna University urged that trace element
recommendations should bear a closer relation to animal requirements with less
of a safety margin to compensate for unknown factors. But he added that in Europe,
some standard nutrient data was incorrect, dating from the time when a large quantity
of feed grain was imported from the USA, whereas now most originates in the EU
or former Soviet Union countries. He said more accurate and sustainable recommendations
required better trace element analyses of feedstuffs, improved data on animal
requirements, quantification of interactions between factors, and switching to
the use of organic high bioavailability trace element supplements.
Stéphane Durosoy, president of the organising committee and director of event
sponsor, Pancosma, said: "The raison d'être for this and future OTEANE symposia
is a sustainable trace element footprint from animal production, consistent with
good animal health, welfare and performance through appropriate use of organic
trace elements."
