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Graphical abstract, Highlights • The seven Eimeria spp. recognised to infect chickens are present globally. • Cryptic Eimeria operational taxonomic units (OTUs) are common in the southern but not northern hemisphere. • Parasite population structure appears to vary between Eimeria spp., The phylum Apicomplexa includes parasites of medical, zoonotic and veterinary significance. Understanding the global distribution and genetic diversity of these protozoa is of fundamental importance for efficient, robust and long-lasting methods of control. Eimeria spp. cause intestinal coccidiosis in all major livestock animals and are the most important parasites of domestic chickens in terms of both economic impact and animal welfare. Despite having significant negative impacts on the efficiency of food production, many fundamental questions relating to the global distribution and genetic variation of Eimeria spp. remain largely unanswered. Here, we provide the broadest map yet of Eimeria occurrence for domestic chickens, confirming that all the known species (Eimeria acervulina, Eimeria brunetti, Eimeria maxima, Eimeria mitis, Eimeria necatrix, Eimeria praecox, Eimeria tenella) are present in all six continents where chickens are found (including 21 countries). Analysis of 248 internal transcribed spacer sequences derived from 17 countries provided evidence of possible allopatric diversity for species such as E. tenella (FST values ⩽0.34) but not E. acervulina and E. mitis, and highlighted a trend towards widespread genetic variance. We found that three genetic variants described previously only in Australia and southern Africa (operational taxonomic units x, y and z) have a wide distribution across the southern, but not the northern hemisphere. While the drivers for such a polarised distribution of these operational taxonomic unit genotypes remains unclear, the occurrence of genetically variant Eimeria may pose a risk to food security and animal welfare in Europe and North America should these parasites spread to the northern hemisphere.

The phylum Apicomplexa includes serious pathogens of humans and animals. Understanding the distribution and population structure of these protozoan parasites is of fundamental importance to explain disease epidemiology and develop sustainable controls. Predicting the likely efficacy and longevity of subunit vaccines in field populations relies on knowledge of relevant preexisting antigenic diversity, population structure, the likelihood of coinfection by genetically distinct strains, and the efficiency of cross-fertilization. All four of these factors have been investigated for Plasmodium species parasites, revealing both clonal and panmictic population structures with exceptional polymorphism associated with immunoprotective antigens such as apical membrane antigen 1 (AMA1). For the coccidian Toxoplasma gondii only genomic diversity and population structure have been defined in depth so far; for the closely related Eimeria species, all four variables are currently unknown. Using Eimeria tenella, a major cause of the enteric disease coccidiosis, which exerts a profound effect on chicken productivity and welfare, we determined population structure, genotype distribution, and likelihood of crossfertilization during coinfection and also investigated the extent of naturally occurring antigenic diversity for the E. tenella AMA1 homolog. Using genome-wide Sequenom SNP-based haplotyping, targeted sequencing, and single-cell genotyping, we show that in this coccidian the functionality of EtAMA1 appears to outweigh immune evasion. This result is in direct contrast to the situation in Plasmodium and most likely is underpinned by the biology of the direct and acute coccidian life cycle in the definitive host.

An experiment was carried out to evaluate supplementation of sorghum straw (SS) with poultry litter (PL) in a single offering/day, and minerals and their effects on feed intake, sorghum straw dry matter disappearance (DMD) in nylon bags and rumen liquid ammonia N concentration. A 4x4 latin square design with 17-day periods and four rumen fistulated stalled cows was used to compare four treatments: (0) SS alone, (M) SS + mineral mixture offered ad libitum (P) SS + 1 kg/day of a concentrate with 83.5 % PL and (PM) SS + supplements used in M and P. The concentrate was offered in one meal and rumen N concentration increased to just over 100 mg/L between 1 and 3 h after feeding, decreasing to less than 50 mg/L after 7 h, levels similar to those on treatments without PL. Dry matter disappearance at 72 h and feed intake increased by the addition of concentrate, but not by mineral supplementation. These results show that the effect of supplementation with PL was due mainly to degradable nitrogen and not by the minerals. A single offering/day is not enough to maintain recommended ammonia N concentrations during most of the day. Um experimento foi realizado para avaliar a suplementação de palhada de sorgo (PS) com cama de frango (CF), em oferta única, e com minerais, e seus efeitos sobre o consumo de ração, desaparecimento de matéria seca de PS (DMS), em sacos de nylon e a concentração de amônia no líquido ruminal. Quatro vacas confinadas e fistuladas no rúmen foram distribuídas em delineamento em quadrado latino 4x4, em período de avaliação de 17 dias, para comparar quatro tratamentos: (0) PS somente, (M) PS + mistura mineral ofertada ad libitum (P) PS + 1kg/dia de um concentrado contendo 83,5% de CF e (PM) PS + 1kg/dia de suplementos usados em M e P. O concentrado foi oferecido em uma única refeição e a concentração de N-NH3 do rúmen alcançando valores um pouco acima de 100 mg/L entre 1 e 3 horas após o consumo da CF, com valores menores que 50 mg/L depois de 7 horas, níveis similares àqueles em tratamentos sem CF. O DMS às 72 horas e consumo de ração foram aumentados com a inclusão de concentrado (P=0,0551), mas não com a suplementação por minerais. Os resultados obtidos indicam que o efeito da suplementação com CF deve-se, principalmente, ao nitrogênio degradável, e não aos minerais, e que uma alimentação por dia não é suficiente para manter a concentração de nitrogênio amoniacal no rúmen recomendada, durante a maior parte do dia.