Meta-analysis of anticoccidial sensitivity testing data

A meta-analysis was performed to compare the efficacy of Monimax® (nicarbazin/monensin) and a combination of nicarbazin/narasin against different Eimeria strains. The meta-analysis was performed using data from 27 different anticoccidial sensitivity tests (ASTs) conducted over a 7-year period from 2013 to 2019. The Eimeria isolates were collected from commercial farms with different anticoccidial control programs in 13 different countries.

AST’s included in this overview

The sensitivity trials were conducted by two different research institutes using comparable, standardized AST protocols (Figure 1). Groups of cage-reared birds were fed diets supplemented with either Monimax® or nicarbazin/narasin. Supplementation started two days before oral inoculation with the different Eimeria field strains (Table 1). Approximately six days after inoculation, lesion scores and performance parameters were recorded and compared to those from an uninfected, untreated control group (UUC) and an infected, untreated control group (IUC).

Figure 1: Standardized anticoccidial sensitivity test (AST) protocol

Table 1: Origin and composition of different inocula included in this meta-analysis

Year Origin inoculum Research Insitute Eimeria species present in the inoculum
2013 Israel INRA, France E. acervulina, E. tenella
2013 UK INRA, France E. acervulina, E. maxima, E. tenella
2013 Italy INRA, France E. acervulina, E. maxima, E. tenella
2013 France INRA, France E. acervulina, E. maxima, E. tenella
2014 Belgium Poulpharm, Belgium E. acervulina, E. maxima, E. tenella
2014 EU Poulpharm, Belgium E. acervulina, E. maxima, E. tenella
2014 Poland INRA, France E. acervulina, E. tenella
2014 Poland INRA, France E. acervulina, E. tenella
2014 Germany INRA, France E. acervulina, E. maxima, E. tenella
2015 Russia INRA, France E. acervulina, E. maxima
2016 Lithuania Poulpharm, Belgium E. acervulina, E. tenella
2016 Poland INRA, France E. acervulina
2016 France INRA, France E. acervulina, E. maxima, E. tenella
2016 New Zealand INRA, France E. acervulina
2017 Russia Poulpharm, Belgium E. acervulina, E. tenella
2017 Russia Poulpharm, Belgium E. acervulina, E. maxima, E. tenella
2017 UK Poulpharm, Belgium E. acervulina, E. maxima, E. tenella
2017 Italy Poulpharm, Belgium E. acervulina, E. maxima, E. tenella
2017 New Zealand INRA, France E. acervulina
2018 Germany Poulpharm, Belgium E. acervulina, E. tenella
2018 Belgium Poulpharm, Belgium E. acervulina
2018 Russia Poulpharm, Belgium E. acervulina
2018 Denmark INRA, France E. acervulina, E. maxima, E. tenella
2018 New Zealand INRA, France E. acervulina, E. maxima
2018 New Zealand INRA, France E. acervulina, E. maxima, E. tenella
2018 Poland INRA, France E. acervulina, E. maxima, E. tenella
2019 Philippines Poulpharm, Belgium E. acervulina, E. maxima

Results

Parasitology

Lesion scores were determined using the Johnson and Reid scoring system. The least square mean (LSM) by species is shown in Table 2.

The nicarbazin/narasin combination did not significantly reduce E. acervulina whereas Monimax® supplementation resulted in a significant reduction of all Eimeria species (E. acervulina, E. maxima and E. tenella) compared to the IUC. The Monimax® treatment group also showed significantly lower scores for both E. acervulina and E. maxima compared to the nicarbazin/narasin treatment group.

Table 2: Lesion scoring results (least square mean) per species using the Johnson and Reid scoring system

Treatment group E. acervulina E. maxima E. tenella
IUC 2.02a 1.20a 1.81a
Monimax 1.69c 0.93c 1.39b
Nicarbazin/narasin 1.98a 1.04b 1.44b
UUC 0.34d 0.48d 0.49c

Different letters in columns indicate significant differences at p<0.01

Performance

Daily weight gain (DWG), daily feed intake (DFI) and feed conversion ratio (FCR) were compared for the different groups during the administration period of the anticoccidial treatments. The results, shown in Table 3, indicate that Monimax® significantly improved all measured performance parameters (DWG, DFI and FCR) compared to the IUC. Although the differences were not statistically different, Monimax® supplementation resulted in better performance parameters compared to the nicarbazin/narasin treatment group.

Table 3: Performance parameters

  DWG DFI FCR
IUC 46.0c 87.1c 2.07c
Monimax 55.0b 90.2b 1.72b
Nicarbazin/narasin 53.8b 89.2bc 1.75b
UUC 67.0a 97.4a 1.47a

Different letters in columns indicate significant differences at p<0.01.

Conclusions

A meta-analysis of data from 27 sensitivity tests with recently collected field strains indicates that: 

  • Monimax® supplementation resulted in significantly lower lesion scores for E. acervulina and E. maxima compared with the group supplemented with nicarbazin/narasin.
  • Numerically higher performance parameters were achieved with Monimax® supplementation compared to the addition of nicarbazin/narasin to the diet.