Diversidad genética de las razas porcinas ibérica y alentejana mediante el genotipado de variantes genéticas en genes mayores y genes candidatos

Las razas porcinas ibérica y alentejana se encuentran biogeográficamente localizadas en el suroeste de la península Ibérica. Estas razas comparten un conjunto de características comunes. Ambas son fenotípicamente muy similares; muestran un bajo índice de crecimiento y una elevada deposición grasa y tienen un sistema común de producción al aire libre en el que se explotan los recursos de la Dehesa. El objetivo del presente trabajo, dentro del marco del proyecto TREASURE, consistió en caracterizar la diversidad genética de ambas razas usando los datos de genotipado de 39 polimorfismos localizados en 34 genes previamente asociados a distintos caracteres de interés económico. Estos polimorfismos fueron genotipados en 950 cerdos pertenecientes a las razas ibérica y alentejana y a 18 razas europeas autóctonas adicionales. Los bajos valores para heterozigosidad observada y esperada indican una baja diversidad genética en ibéricos y alentejanos. Las distancias genéticas estimadas usando DS y FST fueron cercanas a 0 (0.007 y 0.039, respectivamente), sugieren que estas razas son genéticamente muy similares. Asimismo, las técnicas de análisis multivariante utilizadas como análisis de componentes principales y asignación a grupos mostraron que los individuos de estas razas están muy próximos formando clusters diferenciados del resto de razas. Estos resultados concuerdan con los de otros autores que ya mostraron distancias genéticas cortas entre ambas razas usando secuencias de ADN mitocondrial

Genetic diversity of Alentejano and Iberian breeds assessed by polymorphisms of major genes

Alentejano and Iberian breeds are biogeographically located in the southwest of the Iberian Peninsula. These breeds shared a set of common characteristics. Both are phenotypically very similar showing a low growth rate and a high intramuscular fat content and are reared under extensive systems in open range fields. The aim of the current study, carried out within the framework of the TREASURE project, intends to characterize of the genetic diversity of Alentejano and Iberian breeds using the genotyping data of 32 polymorphisms located on 26 major genes. These polymorphisms were genotyped in a total of 950 animals belonging to Alentejano, Iberian and 18 additional European breeds. The low mean values of observed (Ho) and expected (Hs) heterozygosity and FIS point out a low genetic diversity in the analyzed breeds. The genetic distances estimated using Ds and FST revealed values were close to 0 (0.005 and 0.030, respectively), suggesting that these breeds are genetically similar. The population structure analyzed with multivariate methods such as Discriminant Analysis of Principal Component and admixture analyses showed that both breeds were grouped within the same cluster. These results are supported by other authors based on mitochondrial sequences who reported short genetic distances between these breeds. Although complementary analyses using a larger number of markers should be performed, the results of the current analyses support the hypothesis of Alentejano and Iberian could be different strains of the same breed

Diversity across major and candidate genes in European local pig breeds

The aim of this work was to analyse the distribution of causal and candidate mutations associated to relevant productive traits in twenty local European pig breeds. Also, the potential of the SNP panel employed for elucidating the genetic structure and relationships among breeds was evaluated. Most relevant genes and mutations associated with pig morphological, productive, meat quality, reproductive and disease resistance traits were prioritized and analyzed in a maximum of 47 blood samples from each of the breeds (Alentejana, Apulo-Calabrese, Basque, Bísara, Majorcan Black, Black Slavonian (Crna slavonska), Casertana, Cinta Senese, Gascon, Iberian, Krskopolje (Krskopoljski), Lithuanian indigenous wattle, Lithuanian White Old Type, Mora Romagnola, Moravka, Nero Siciliano, Sarda, Schwa-bisch-Hallisches Schwein (Swabian Hall pig), Swallow-Bellied Mangalitsa and Turopolje). We successfully analyzed allelic variation in 39 polymorphisms, located in 33 candidate genes. Results provide relevant information regarding genetic diversity and segregation of SNPs associated to production and quality traits. Coat color and morphological trait-genes that show low level of segregation, and fixed SNPs may be useful for traceability. On the other hand, we detected SNPs which may be useful for association studies as well as breeding programs. For instance, we observed predominance of alleles that might be unfavorable for disease resistance and boar taint in most breeds and segregation of many alleles involved in meat quality, fatness and growth traits. Overall, these findings provide a detailed catalogue of segregating candidate SNPs in 20 European local pig breeds that may be useful for traceability purposes, for association studies and for breeding schemes. Population genetic analyses based on these candidate genes are able to uncover some clues regarding the hidden genetic substructure of these populations, as the extreme genetic closeness between Iberian and Alentejana breeds and an uneven admixture of the breeds studied. The results are in agreement with available knowledge regarding breed history and management, although largest panels of neutral markers should be employed to get a deeper understanding of the population’s structure and relationships

Protein requirements of Cinta Senese pigs from 30 to 60 kg: Preliminary results

Knowledge of protein requirements of pigs during the first phase of life is crucial for both achieving high growth rates and avoiding nitrogen waste. Autochthonous breeds possess specific requirements in this regard and the literature is poor even for the Cinta Senese breed. Thus, the effect of different level of crude protein (CP) in Cinta Senese pigs, between 30 and 60 kg, was evaluated within the TREASURE* project. Twelve male pigs were individually reared indoor, fed with four isoenergetic diets with different levels of CP (18, 16, 14 and 12%) equally distributed among animals. The animals, with an initial average live weight of 27 kg, were fed ad libitum and slaughtered after 2 months of trial. Left side carcass was sectioned in six cuts: head, neck, loin, shoulder, ham and ribs. Each cut has been dissected into the main tissues. As regards in vita performance a slightly higher growth rates with decreasing protein levels were recorded (ADG of 0.781, 0.774, 0.755 and 0.729 kg/d respectively for 12, 14, 16 and 18% of CP), though only the two extreme levels of CP (12 vs 18%) resulted statistically different (P=0.05). Cuts weights and percentage of the main tissues were similar between diets. The diet with 12% of CP may be the optimal compromise for the growth of the Cinta Senese pigs from 30 to 60 kg of live weight.La conoscenza del fabbisogno proteico dei suini durante la prima fase di vita è fondamentale sia per ottenere elevati tassi di crescita sia per evitare sprechi di azoto. Le razze autoctone possiedono specifici requisiti in questo senso e la letteratura è scarsa anche una razza come la Cinta Senese. Pertanto, l’effetto di diversi livelli di proteina grezza (CP) in maiali di Cinta Senese, tra 30 e 60 kg, è stata valutata nell’ambito del progetto TREASURE*. Dodici suini maschi sono stati allevati singolarmente al chiuso, alimentati con quattro diete isoenergetiche con diversi livelli di CP (18, 16, 14 e 12%) equamente distribuite tra gli animali. Gli animali, con un peso vivo medio iniziale di 27 kg, sono stati alimentati ad libitum e macellati dopo 2 mesi di prova. Alla macellazione la mezzena sinistra della carcassa è stata sezionata in sei tagli: testa, collo, lombo, spalla, prosciutto e costole. Ogni taglio è stato sezionato nei tessuti principali. Per quanto riguarda le prestazioni in vita è stato notato un tasso di crescita leggermente superiore al diminuire del livello della proteina (ADG di 0,781, 0,774, 0,755 e 0.729 kg / d, rispettivamente per 12, 14, 16 e 18% di CP), anche se solo i due livelli estremi di CP (12 vs 18%) hanno comportato differenze statistiche (P = 0,05). Le percentuali dei tagli commerciali e dei tessuti principali sono risultate simili tra le diete. La dieta con il 12% di CP può essere il compromesso ottimale per la crescita delle Cinta Cenese da 30 a 60 kg di peso vivo