Anticoccidial resistance in poultry

Abstract

This study aimed to determine the resistance of coccidia to ionophores used in broiler farms in Tizi-Ouzou province, Algeria. Droppings were collected and recovered Eimeria oocyst isolates were analysed by morphometry to determine their composition, and then inoculated by peros into chicks of the Arbor Acres strain, reared on the ground. Four of six groups of chicks were treated to test the sensitivity of oocysts to four anticoccidial agents added to their growth feeds [(robenidine (33 ppm), monensin (120 ppm), narasin-nicarbazin (80 ppm) and salinomycin (60 ppm)], while the other two groups were controls. The results revealed the presence of total resistance to monensin and robenidine, and partial resistance to salinomycin and the narasin-nicarbazin combination. The lack of sensitivity to monensin and robenidine was unsurprising, given their inappropriate and unreasonable use for years as the only anticoccidial compounds. The appearance of partial resistance to narasin-nicarbazin and salinomycin suggests the development of cross-resistance in the Eimeria population. The possibility of a relatively uniform composition of Eimeria species collected in these farms indicates that Eimeria acervulina and Eimeria maxima develop resistance more quickly to these ionophores. Finally, a control strategy must be rigorously developed by considering other molecules that are alternatives to anticoccidials.Cilj je studije bio odrediti otpornost kokcidija na jonofore rabljene na farmama tovnih pilića u provinciji Tizi-Ouzou. Prikupljen je izmet i pronađeni izolati Eimeria oociste su analizirane morfometrijom da bi se odredio njihov sastav te su njima per os cijepljeni pilići Arbor Acres soja, uzgojeni na zemlji. Četiri od šest skupina tih pilića podvrgnuto je ispitivanjem osjetljivosti oocista na četiri antikokcidika dodanih njihovoj hrani [(robenidin (33 ppm), monenzin (120 ppm), narazin-nikarbazin (80 ppm) i salinomicin (60 ppm)], druge dvije skupine bile su kontrolne. Rezultati studije otkrili su prisutnost potpune otpornosti na monenzin i robenidin, kao i djelomičnu otpornost na salinomicin i kombinaciju narazin-nikarbazin. Izostanak osjetljivosti na monenzin i robenidin nije bio iznenađujući obzirom na njihovu neprikladnu i nerazumnu dugogodišnju uporabu kao jedine antikokcidne tvari. Pojava djelomične otpornosti na narazin-nikarbazin i salinomicin ukazuje na postojanje razvoja unakrsne otpornosti u populaciji Eimeria. Mogućnost relativno ujednačenog sastava Eimeria vrste prikupljene na ovim farmama upućuje na to da Eimeria acervulina i Eimeria maxima brže razvijaju otpornost na rabljene jonofore. Zaključno, potrebno je rigorozno razviti strategiju kontrole razmatrajući druge molekule koje su alternativne antikokcidicima.