The reliability of several analytical methods proposed to predict the feeding system received by Iberian pigs during the fattening period has been contrasted. Samples of subcutaneous adipose tissue were analyzed from 38 batches of pigs fattened in three seasons of montanera (acorn and pastures feeding). They corresponded to the four categories described in the Quality Standard for Iberian pig products: 251 samples of bellota, 164 of recebo, 197 of cebo de campo and 137 of cebo. To perform the study, the following analytical methods were used: fatty acid quantification, NIR, alpha and gamma tocopherol, chemical sensor, triacilglycerides, stable isotopes and neophytadiene. The laboratories received the samples without any information about the fattening system to which they belonged and remitted their predictions with respect to the above categories. The results showed a high percentage of accurate predictions of the methods when the fattening type corresponds to the extreme categories (bellota and cebo), however, the methods had difficulty in discerning between samples from a mixed feeding regime with acorn and feed (recebo) and problems when pigs are fattened with compound feeds including vegetable fats with high levels of oleic acid. Although a simplification into only two categories (cebo/campo and recebo/bellota) results in a success rate higher than 90% for some methods, the combination of two or three techniques with problematic samples allows for differentiating among the four categories with the same accuracy.

Se ha contrastado la fiabilidad de varios métodos analíticos para determinar el tipo de alimentación recibida durante el cebo por cerdos Ibéricos a partir de muestras de tejido adiposo subcutáneo, procedentes de 38 partidas de cerdos de tres campañas de montanera. Las muestras correspondieron con las categorías de alimentación contempladas en la Norma de Calidad: 251 fueron de bellota, 164 de recebo, 197 de campo y 137 de cebo. Los métodos contrastados han sido ácidos grasos, NIR, alfa y gamma tocoferol, sensor químico, triacilglicéridos, isótopos estables y neofitadieno. Los distintos laboratorios recibieron las muestras sin información sobre el tipo de alimentación y remitieron sus predicciones respecto a las categorías previamente mencionadas. Los resultados obtenidos mostraron un elevado porcentaje de aciertos de los métodos cuando la alimentación se corresponde con las categorías extremas (bellota y cebo), sin embargo existía una dificultad en clasificar correctamente las muestras de cerdos de alimentación mixta con bellota y pienso (recebo) y confusión de algunos métodos cuando los cerdos son cebados con piensos que incluyen grasas vegetales con altos niveles de ácido oleico. Aunque la consideración de sólo dos categorías (cebo/campo y recebo/bellota) eleva el nivel de acierto por encima del 90% en algunos métodos, la combinación de dos o tres técnicas para muestr...

Iberian pigs are produced in a range of low, medium and high input production systems, all of them focused on obtaining meat and dry-cured products characterized by their high sensorial quality. The traditional production system includes a finish-fattening period of four or five months (November to March) known as montanera (M) and based on the ad libitum intake of acorns and pastures (López-Bote, 1998). However, most of the Iberian pigs are fattened with an intensive management using commercial feeds. A medium input production system has been recently developed, where the pigs also use the territory (free-range rearing) but are mainly fattened with commercial feeds besides of the seasonal availability of grass or stubble. This second free-range feeding system is named campo (C). The percentages of these three production systems are AbstractGenotype by environment interaction (G×E) is a potential source of reduced efficiency in genetic improvement programs in livestock. The objective of the current work consisted of checking the existence of G×E interaction in carcass traits and in intramuscular fat content (IMF) in Iberian pigs fattened in two free-range systems. Genetic component and estimated breeding values (EBV) of the percentage of hams, shoulders and loins and IMF in loin were obtained from records of 4,348 and 1,818 pigs fattened in campo (C) and montanera (M) systems, respectively. A multitrait model where the performances of each system are considered as different traits was implemented. Three selection indexes were built with different treatments about the quality trait, two of them based in the optimal trait theory. The Pearson correlation between EBV and indexes and the Spearman correlation between the rankings of progenies of 21 boars fattened in both systems were calculated. Heritability results were different in both systems (h 2 range from 0.43 to 0.66 and from 0.24 to 0.33 in C and M system, respectively) and genetic correlation of same traits expressed in the two systems also pointed out to a weak G×E interaction (0.64, 0.67 and 0.66 in hams, shoulders and IMF, respectively). Pearson and Spearman correlations were always significantly different to 1. The obtained results advised to consider this G×E interaction in the analysis model of a breeding program focused on free range production system and to include IMF in the index selection assuming an optimum range for this quality trait, in order to avoid negative effects of selection for carcass performances.

Non-ruminants Full-length research article Feed efficiency and loin meat quality in Iberian pigs ABSTRACT-We investigated the ability to predict production performance in Iberian pigs in an extensive production system from measurements of feed efficiency measured intensively. The second objective of this work was to study the relationship between feed efficiency and meat quality (composition, juiciness, tenderness, color, and subcutaneous fatty acid composition) and if cooked and cured quality properties can be predicted by properties in fresh meat. Thirty Iberian sows received successively a restricted diet of concentrate (P1 concentrate) and acorns (P2 acorn) intensively and an ad libitum diet of acorns supplemented with a restricted amount of concentrate (P3 montanera) extensively. Pigs that were more feed efficient on concentrate were less feed efficient on acorns and had higher body weight gain during the montanera. Improved feed efficiency on acorns reduced the concentration of α-linolenic and linoleic fatty acid composition of subcutaneous fat. Faster body weight gain in montanera resulted in a desirable reduction in cooking loss and a reduction in palmitic acid content in subcutaneous fat, and a potentially undesirable reduction in meat redness. Tenderness in cooked or cured loin was not significantly related to tenderness in the raw product. Cooking loss was positively related to purge and centrifugal drip loss and to color coordinates a* 24 and b* 24 in raw samples. We conclude that feed efficiency and body weight gain may be improved in the traditional Iberian production system, with a positive effect on cooking loss but potentially resulting in paler meat.

Background: Phenotypic variability for productive and meat quality traits has been largely studied in Iberian pigs, especially in genetic selection and nutritional experiments. Complex interactions among genetic background, diet composition and gut microbiota difficult the evaluation of true effects of each factor on phenotypes. In order to disentangle these interactions, we evaluated changes in gut microbiota composition comparing Iberian and Duroc pigs fed diets with different energy source.Results: Gut microbiota composition was analysed in feces from 48 pigs (Iberian and Duroc) fed a standard diet or a sunflower oil-enriched diet with high oleic acid content (6%). A higher richness was observed for Iberian pigs (p < 0.05) and compositional analysis was applied for beta-diversity, differential abundance and pairwise log-ratio analyses. We found significant differences in overall microbiota composition between breeds, and also between diets inside breeds, to a lesser extent. Differential abundance analysis revealed that Duroc animals have more proportion of Actinobacteria and Prevotella, while Iberian replace those microorganisms with other more variable taxa. According to dietary differences, high-oleic fed animals were richer in Prevotella. We also found microbial ratios capable of separating animals by breeds and diets, mostly related to Actinobacteria.Conclusion: This study reveals that both genetic background and diet composition might have a relevant impact in gut microbiota composition. The application of compositional data analysis has facilitated the identification of microorganisms and ratios as possibly related to metabolic changes due to genetic background and, to a lower extent, to dietary changes. This may lead to a relevant progress in the knowledge of interactions between pig genetics, environment and gut microbiota.

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