Pubblicato su: SPVet.it - ISSN 1592-1581 (http://spvet.it/; http://indice.spvet.it); Numero 86/2014 34° International Society for Animal Genetics Conference Xi’an, July 28th- August 1st 2014

Statistical evaluation of scrapie susceptibility in some Italian sheep breeds Carla Sebastiani1 , Ludovica Curcio1,2 , Marcella Ciullo1 , Carmen Maresca1 , Annalisa Dettori1 , Emiliano Lasagna2, Massimo Biagetti1 1. Istituto Zooprofilattico Sperimentale dell’ e delle , Perugia, ; 2. Department of Agricultural, Food and Environmental Science, University of Perugia, Italy

INTRODUCTION

The aim of this study was to perform a statistical evaluation of PRNP allele and genotype frequencies of the sheep population of Umbria and Marche regions in order to evaluate the probability to find genotypes susceptibles or resistant to scrapie in 8 italian sheep breeds: Sarda, Merinizzata, Merinos, Bergamasca, Massese, , and .

MATERIALS & METHODS

Allelic Discrimination by Real-time PCR

Farms 136 154

171.1 171.2

Blood DNA sampling extraction

DNA from 171.2 different breeds 136 StepOne Plus Real-Time PCR System 154

Statistical analysis Odds Ratio (OR) with 95% confidence interval (CI) was calculated as a measure of association between breed and frequencies of susceptible and resistant alleles and genotypes. Data with P-value ≤0.05 were considered statistically significant.

RESULTS

Analysis on the behavior of the breeds respect to ARR allele and susceptible genotypes based on OR calculation on allele and genotype frequencies, respectively. Probability to have ARR resistant allele Probability to have a susceptible genotype

BREED OR (CI 95%) P-value BREED OR (CI 95%) P-value

Sarda Vs other breeds 1,26 (1,20-1,32) 0,000 Sarda Vs other breeds 0,66 (0,62-0,72) 0,0000

Merinizzata Vs other breeds 0,64 (0,61-0,68) 0,000 Merinizzata Vs other breeds 1,76 (1,65-1,88) 0,0000 Bergamasca Vs other 0,85 (0,78-0,93) 0,000 breeds Merinos Vs other breeds 0,79 (0,70-0,89) 0,0001 Merinos Vs other breeds 1,14 (1,05-1,24) 0,003 Bergamasca Vs other breeds 1,09 (0,97-1,22) 0,1555

Massese Vs other breeds 2,14 (1,94-2,36) 0,000 Massese Vs other breeds 0,34 (0,29-0,40) 0,0000

Fabrianese Vs other breeds 0,54 (0,42-0,68) 0,000 Fabrianese Vs other breeds 0,90 (0,66-1,23) 0,4838 Appenninica Vs other 1,09 (0,87-1,38) 0,440 Appenninica Vs other breeds 0,82 (0,58-1,17) 0,2566 breeds Comisana Vs other breeds 2,29 (1,69-3,11) 0,000 Comisana Vs other breeds 0,31 (0,17-0,56) 0,0000 Sarda, Merinos, Massese and Comisana breeds show a lower Five breeds had an higher probability to present ARR allele probability to have a sensitive genotype than other breeds respect to all other breeds (OR>1); in particular, Sarda, (OR<1). Fabrianese and Appenninica have OR<1, while Merinos, Massese, Comisana, and Appenninica. P-values were Bergamasca breed have OR>1, but P-values were not statistically significant for all breeds except for Appenninica. statistically significant in both cases.

DISCUSSION AND CONCLUSION

The results of statistical analysis as a whole, demonstrate that Sarda, Comisana, Massese and Merinos breeds have a low probability to be affected by scrapie than the other breeds analyzed and so they could be classifiable as resistant breeds. As regards to the other breeds, they have a medium to high probability to be susceptible to scrapie.

This project was funded by the Italian Ministry of Health , RC IZSUM 08/2011

Stampato a cura dell'Unità Operativa di Supporto Biblioteca, Informazione, Editoria (2013).

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