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danmap 2015 40 antimicrobial consumption in animals 4. textbox 4.1 consumption of
coccidiostats
in
poultry
in denmark, 2008-2015 background: coccidiosis is one of the most important
poultry
diseases worldwide, and left unattended, it is a seriously limiting factor for intensive production of broilers on litter. coccidia are highly host specific protozoa. most coccidia in
poultry
belong to the genus eimeria and grow and multiply intracellularly in epithelial and subepithelial cells, usually in the intestines. they have a direct life cycle. oocysts are passed with feces to the environment where they sporulate and are ingested by the host. the life cycle in the gut takes about 7 days, followed by sporulation in 1-2 days under optimal conditions, resulting in hundreds of thousands of oocysts produced from one single ingested oocyst. the sporulated oocysts are resistant to most environmental conditions and can survive for months or even years outside a host, which is a key factor in the epidemiology of coccidiosis. under field conditions, day old chickens are exposed to low doses of coccidia and develop immunity that will be life long as there is a frequent low-grade exposure to infection. clinical outbreaks of coccidiosis are characterized by sudden onset of diarrhoea and elevated mortality. even more important are subclinical infections that impair growth and feed conversion, causing considerable production losses.
coccidiostats
: anticoccidial agents were introduced in the 1940s and have been crucial in controlling coccidiosis especially dur- ing the evolvement of the broiler industry. the coccidiostatic effects enable development of protective immunity. eleven differ- ent
coccidiostats
have been authorised for use in the eu; both ionophores and non-ionophores. ionophores (monensin, narasin, lasalocid, salinomycin, maduramicin) have been widely
used
since the early 1970s. ionophores are fermentation products that affect ion transport across cell membranes in target- and non-target species. ionophores have antibacterial activity, and there are toxic interactions between some ionophores and some antibiotics. non-ionophore (chemical)
coccidiostats
have no antibac- terial effect. these drugs are thiamine analogues (amprolium), carbanilides (nicarbazin), and triazinone derivatives (diclazuril, toltrazuril). the environmental impact of
coccidiostats
needs further investigation. consumption: the total use of
coccidiostats
in denmark increased steadily from 2008 to 2015 and salinomycin has been the dominating anticoccidial drug
used
in denmark throughout this period (figure 1, table 1). the use of a combination of narasin and nicarbacin has been increasing since 2009. since 2014 narasin also increased, mirroring that this drug is
used
after the first 25 days of the broiler growing period, as the withdrawal time is zero days. the lower but rather constant consumption of monensin and lasalosid comes from the turkey producers that use monensin in winter periods and lasalosid in summer. since 2012,lasalocid has also been
used
in feed for gamebirds. 0 2 4 6 8 10 12 14 16 18 2008 2009 2010 2011 2012 2013 2014 2015 use of cocciostats for
poultry
, tonnes e757 monensinnatrium e763 lasalosidnatrium e765 narasin e766 salinomycinnatrium e772 narasin/nicarbazin other
coccidiostats
figure 1. consumption (tonnes) of the most frequently
used
coccidiostats
in
poultry
, denmark danmap 2015
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