16 research outputs found
Comparison between Direct and Competitive Models to Investigate Variation of Carcass and Ham Quality Traits in Heavy Pigs
Social interactions among animals raised in pens can affect their performance. In this study direct and competitive models were compared to investigate the influence of social genetic effects on variation of carcass weight (CW), carcass lean meat content (LM) and ham round shape (RS) in heavy pigs. Four sequential models including, in addition to sex and slaughter group fixed effects, the random effects of the social group, litter (full-sibs family), direct and social genetic effects of pigs were evaluated. Social group and litter effects accounted for about 4 and 3% of the phenotypic variance, respectively. When social genetic effects were added to model, a small social heritability was estimated for all traits (from 0.3 to 0.7% of the phenotypic variance). A negative correlation between direct and social effects was estimated for LM and RS, reducing the total heritable variance available for selection. Model comparison showed that the best fit was provided by the model including only direct additive genetic effects of pigs. So, this model seems still preferable for the genetic evaluation of the investigated traits
Effects of Îș-CN Glycosylation on Rennet Coagulation Properties of Milk in Simmental Cattle
Contents of casein fractions are known to affect coagulation properties and cheese yield of milk, but studies on the effects of Îș-CN composition on variation of coagulation properties of milk are still very scarce. Effects exerted by Îș-CN composition on variation of milk coagulation properties (MCP) were investigated using 2,084 individual milk samples of Simmental cows. Rennet coagulation time (RCT), and curd firmness (A30) were measured using a computerized renneting meter. Milk protein composition and genotypes at CSN2, CSN3 and BLG were obtained by reversed-phase HPLC. The percentage ratios of Îș-CN (ÎșCN%), of Glycosylated-Îș-CN (G-ÎșCN%), and Unglycosylated-Îș-CN (U-ÎșCN%) to total casein were measured. The degree of glycosylation (GD) was measured as the percentage ratio of glycosylated-Îș-CN to total Îș-CN. A difference of 1.7 min (corresponding to 0.37 SD of the trait) was observed for the average RCT of the two extreme classes of ÎșCN% content. RCT decreased when ÎșCN% and G-ÎșCN% increased, whereas U-ÎșCN% exhibited a slightly unfavourable effect on the onset of the coagulation process. A slight decrease of RCT was also observed for high GD, although this effect was less clear than that of G-ÎșCN%. A favourable effect of ÎșCN%, G-ÎșCN% and GD on A30 was also detected
Comparison between Direct and Competitive Models to Investigate Variation of Carcass and Ham Quality Traits in Heavy Pigs
Social interactions among animals raised in pens can affect their performance. In this study direct and competitive models were compared to investigate the influence of social genetic effects on variation of carcass weight (CW), carcass lean meat content (LM) and ham round shape (RS) in heavy pigs. Four sequential models including, in addition to sex and slaughter group fixed effects, the random effects of the social group, litter (full-sibs family), direct and social genetic effects of pigs were evaluated. Social group and litter effects accounted for about 4 and 3% of the phenotypic variance, respectively. When social genetic effects were added to model, a small social heritability was estimated for all traits (from 0.3 to 0.7% of the phenotypic variance). A negative correlation between direct and social effects was estimated for LM and RS, reducing the total heritable variance available for selection. Model comparison showed that the best fit was provided by the model including only direct additive genetic effects of pigs. So, this model seems still preferable for the genetic evaluation of the investigated traits
Effects of Îș-CN Glycosylation on Rennet Coagulation Properties of Milk in Simmental Cattle
Contents of casein fractions are known to affect coagulation properties and cheese yield of milk, but studies on the effects of Îș-CN composition on variation of coagulation properties of milk are still very scarce. Effects exerted by Îș-CN composition on variation of milk coagulation properties (MCP) were investigated using 2,084 individual milk samples of Simmental cows. Rennet coagulation time (RCT), and curd firmness (A30) were measured using a computerized renneting meter. Milk protein composition and genotypes at CSN2, CSN3 and BLG were obtained by reversed-phase HPLC. The percentage ratios of Îș-CN (ÎșCN%), of Glycosylated-Îș-CN (G-ÎșCN%), and Unglycosylated-Îș-CN (U-ÎșCN%) to total casein were measured. The degree of glycosylation (GD) was measured as the percentage ratio of glycosylated-Îș-CN to total Îș-CN. A difference of 1.7 min (corresponding to 0.37 SD of the trait) was observed for the average RCT of the two extreme classes of ÎșCN% content. RCT decreased when ÎșCN% and G-ÎșCN% increased, whereas U-ÎșCN% exhibited a slightly unfavourable effect on the onset of the coagulation process. A slight decrease of RCT was also observed for high GD, although this effect was less clear than that of G-ÎșCN%. A favourable effect of ÎșCN%, G-ÎșCN% and GD on A30 was also detected
Innovation in the pig breeding sector: new traits, new models and new methods in breeding value prediction
The most important income for the pig industry in Italy arises from the processing of meat in high-added-value typical products, mainly dry-cured hams having Protected Designation of Origin (PDO) label. Even through use of purebred pigs is not an exception, raw thighs are largely obtained from crossbred (CB) animals, which are slaughtered at heavy body weight (BW) (nearly 165 kg) and advanced age (270 d or more).
Breeding programs of pig lines linked to dry-cured ham production should focus on enhancement of growth performance, carcass traits and qualitative and technological properties of green thighs, in order to comply the rules dictated by the disciplinary of production. Moreover, the breeding goal (aggregate genotype) must be defined at the level of the âCB slaughter animalâ, so that the unfavourable effect on selection response due to genetic differences between purebreds (PB) and crossbreds, but also to environmental differences between nuclei and commercial farms, is alleviated. Given that breeding values (EBV) estimated using purebred phenotypes are often poorly related to the breeding goal defined at crossbred levels, the approach called âcombined crossbred-purebred selectionâ is used in traditional genetic evaluation. It consists in estimation the EBV for the relevant traits using both PB and CB information. This approach is troublesome because it requires the availability of crossbred animals (half-sibs of the PB breeding candidates) which must be specifically reared as tested animals, and the phenotypic records of traits difficult and expensive to measured (as ham quality traits and curing losses). Moreover, EBV for members of a PB full-sibs family are identical when no PB individual information is available.
The main aim of this thesis was to provide new knowledge about innovative traits important in heavy pig industry and to propose new statistical models and genetic evaluation procedures to enhance the prediction of breeding values for carcass traits, and qualitative and technological properties of raw thighs.
The studies were carried out in collaboration with an Italian breeding company, Gorzagri s.s. (Fonzaso, Italy). It aims at producing boars (C21 line) and gilts (Goland line) used in commercial farms as sires and dams of CB pigs which are reared for production of PDO dry-cured hams.
The first part of this thesis aimed to investigate the prevalence and the genetic determinism of boar taint (BT), a new trait related to both meat quality and animal welfare which is becoming increasingly important for pig industries in EU countries after the decision to ban surgical castration of piglets from 1 January 2018, and hence, the need to find alternative to reduce BT in entire male pigs.
The objectives of the study were: to evaluate the prevalence of BT in intact male pigs at 160 and 220 d of age, and to estimate the genetic parameters for BT compounds at the two different ages and the genetic relationships with growth traits.
Contents of androstenone (AND), skatole (SKA) and indole (IND) have been quantified by HPLC with fluorescence detection in biopsy samples of adipose tissues collected in-vivo from the neck area of 500 C21 entire male pigs at 160 and 220 d of age. In addition, for 100 of the investigated animals, BT compounds were quantified also in a sample of subcutaneous fat of raw thighs collected at slaughterhouse.
Contents of BT compounds measured in intact male pigs at 220 d were higher than those found at 160 d of age, as well as the percentage of samples that exceeded the sensory thresholds discriminating tainted from untainted carcasses. Thus, the prevalence of BT is expected to be greater in mature and heavy pigs in respect to young and light pigs. The high phenotypic correlations between the contents of BT compounds measured in backfat and ham subcutaneous fat suggest that BT might be relevant also in PDO dry-cured hams. Medium-high heritabilities were found for contents of BT compounds at both ages, indicating that reduction of BT by means of genetic selection seems a valid alternative to surgical castration in pigs slaughtered at heavy BW. Genetic correlations between the contents of BT compounds measured at the two different ages were moderate to high. However, Spearmanâs rank correlations revealed that the breeding candidates ranked differently when measures of BT compounds taken at the different ages are used. Finally, weak genetic correlations were found between BT compounds and growth traits, indicating that selective breeding to decrease the contents of AND, SKA and IND is expected to have trivial effects on growth performance.
In the second section of this thesis the contribution of social genetic effects on variation of carcass and ham quality traits was investigated. In the current breeding program of C21 line the impact of the genetic effect of an individual on phenotypes of its pen mates (called social genetic effects or heritable social effects) is neglected. If present, social genetic effects are part of the total heritable variance and they affect the response to selection.
The aims of this study were to estimate (co)variance components for body weight adjusted at 270 d (BW270), carcass and ham quality traits using direct and competitive models, and to compare the ability of such models to fit the data.
The study was carried out on 9,871 CB finishing pigs raised in social groups containing from 4 to 7 individuals (6.1 pigs per group on average). Four sequential univariate animal models were compared through likelihood ratio test. REML estimates of covariance components were obtained for BW270, carcass backfat depth and lean meat (CLM), iodine number (IOD) and linoleic acid content of raw ham subcutaneous fat, subcutaneous fat depth in the proximity of semimembranosus and quadriceps femoris muscles, and linear scores for ham round shape (RS), subcutaneous fat (SF), and marbling.
Model comparison based on likelihood ratio test revealed that the model accounting for heritable social effects was significantly better than the best direct model for BW270, CLM, IOD, RS, and SF. The contribution of social genetic effects to the total heritable variance was large for CLM and BW270, whereas the one for ham quality traits was lower. The correlation between direct and social additive genetic effects was positive for BW270, but it was not significantly different from zero, suggesting independence between direct and social genetic effects for this trait. In contrast, a negative genetic covariance between direct and associative components was found for CLM, IOD, RS, and SF, which reduced the total heritable variance exploitable for genetic selection. The results obtained in this study suggest that social genetic effects affect variation in traits relevant for heavy pigs used in dry-cured hams manufacturing and, hence, the procedures for estimation of breeding values should take heritable social effects into account.
The third part of this thesis aimed to investigate new methods including genomic information in order to enhance the EBV prediction for traits related to carcass, ham quality and manufacturing of dry-cured hams. Genomic selection (GS) approach might overcome some of the drawbacks of current procedures for genetic evaluation of C21 line based on sib-testing.
The objective of the first study regarding GS was to develop and to investigate GS procedures based on single step BLUP (SSBLUP) methodology for genomic evaluation of PB breeding candidates of C21 boar line for traits relevant for dry-cured ham production.
Observations on BW270, carcass and ham quality traits were recorded from 11,488 CB finishing pigs. In addition, for 1,878 of the investigated animals, phenotypes for weight losses occurring during salting, resting and curing production stages were available. To constitute the reference population, 1,088 CB pigs, 136 nucleus boars (C21_NB: sires of CB tested pigs) and 500 C21 half-sibs of CB animals (C21_HS: half-sibs of CB tested animals) were genotyped for 8,826 single nucleotide polymorphisms using GGP Porcine LD Chip. Traditional evaluation was performed using BLUP methodology, whereas genomic evaluation was carried out using SSBLUP method which combine pedigree and genomic information in order to estimate genomic breeding values (GEBV) for both genotyped and ungenotyped animals. Pearsonâs correlation coefficients between EBV and GEBV (r_(EBV,GEBV)) were calculated in order to compare traditional and genomic evaluation. In addition, the 500 C21_HS with genotypic information were used to validate the prediction equation.
High r_(EBV,GEBV) were observed for all the investigated traits for both CB animals, C21_NB, suggesting that genetic merit estimated using GS was consistent with breeding values prediction from traditional evaluation. Positive and moderate to high r_(EBV,GEBV) were observed for C21_HS used in validation population. Differences in ranks of breeding candidates were found when they were based on traditional EBV or GEBV. In contrast to EBV, GEBV differed for members of a PB full-sibs family when they had genomic information. Thus, GS allows to choose the best animals based on âindividualâ genetic merit rather than âfamilyâ merit, increasing the accuracy of selection and reducing the rate of inbreeding. In addition, GS procedures might simplify genetic evaluation of PB breeding candidates of C21 boar line for traits difficult to measure.
As found in the second part of this thesis, competitive models provided a better fit than classical direct model for BW270, CLM, IOD, RS and SF. Hence, for these traits, traditional genetic evaluation accounting for heritable social effects was compared to SSBLUP analysis performed using a competitive model. The dataset used in this study was the same described above. For animals in validation population, positive and moderate to high Spearmanâs correlation coefficients between direct EBV and direct GEBV were found for all the investigated traits, as well as between total breeding values and total genomic breeding values (TGBV). Hence, differences in ranks of breeding candidates were observed even when social genetic effects were included in the genomic evaluation. In fact, GS procedures accounting for heritable social effects allow to obtain individual TGBV rather than âfamilyâ TBV, increasing the benefit of GS for genetic evaluation of PB boar lines linked to dry-cured ham production.I profitti piĂč rilevanti per lâindustria suinicola italiana derivano dalla trasformazione della carne in prodotti tipici di alto valore economico, principalmente prosciutti crudi con Denominazione di Origine protetta (DOP). Le cosce fresche destinate alla produzione dei prodotti DOP derivano principalmente da soggetti ibridi che vengono macellati a pesi elevati (circa 165 kg) e ad etĂ avanzate (almeno 270 giorni).
I programmi di selezione delle linee suine destinate alla produzione dei prosciutti crudi dovrebbero focalizzarsi sul miglioramento delle prestazioni di crescita, della qualità della carcassa e delle caratteristiche qualitative e tecnologiche delle cosce fresche, cosicché i requisiti dettati dai disciplinari di produzione siano soddisfatti. In questo scenario gli obiettivi di selezione devono essere definiti a livello di soggetto ibrido, piuttosto che a livello di linea pura. I valori genetici (breeding values, EBV) stimati utilizzando le informazioni fenotipiche dei soggetti di linea pura sono poco correlati con gli obiettivi di selezione definiti al livello dei soggetti ibridi. Per questo la valutazione genetica dei candidati riproduttori di linea pura attualmente avviene attraverso un approccio che combina informazioni derivanti sia da soggetti puri che da soggetti ibridi. Questo approccio presenta alcune criticità dovute alla necessità di allevare appositamente soggetti ibridi (mezzi fratelli dei candidati riproduttori di linea pura) per ottenere i rilievi fenotipici per caratteristiche che alcune volte sono difficili da misurare (come i caratteri di qualità della coscia o i cali di stagionatura). Inoltre, quando nella valutazione genetica non sono incluse informazioni fenotipiche rilevate sugli animali di linea pura, i EBV per i candidati riproduttori che appartengono alla stessa famiglia di fratelli pieni sono identici.
Lâobiettivo principale della tesi Ăš stato quello di fornire nuove conoscenze su caratteri innovativi per lâindustria del suino pesante e di proporre nuovi modelli statistici e procedure di valutazione genetica per migliorare la predizione dei EBV per caratteri legati alla qualitĂ della carcassa e delle cosce fresche destinate alla produzione dei prosciutti crudi DOP.
Gli studi qui presentati sono stati condotti in collaborazione con unâazienda suinicola italiana, Gorzagri s.s (Fonzaso, Italia). Essa ha come obiettivo la produzione di verri (linea C21) e scrofe (linea Goland) usati negli allevamenti commerciali come padri e madri di soggetti ibridi destinati alla produzione dei prodotti DOP.
La prima parte della tesi si proponeva di studiare lâincidenza e il determinismo genetico dellâodore di verro, un nuovo carattere associato sia alla qualitĂ della carne che al benessere animale, il quale sta diventando sempre piĂč rilevante per lâindustria suinicola italiana ed europea dopo la decisione di abbandonare la castrazione chirurgica dei suinetti maschi a partire dal 1 gennaio 2018. Questo impone la necessitĂ di trovare valide alternative a questa pratica per ridurre lâodore di verro nei suini maschi interi.
Allo scopo di indagare la possibilitĂ di sfruttare la selezione genetica per limitare lâodore di verro nel suino pesante, gli obiettivi dello studio sono stati: valutare la prevalenza dellâodore di verro in suini maschi interi di 160 e 220 giorni dâetĂ e stimare i parametri genetici per i composti responsabili del problema alle due diverse etĂ nonchĂš le relazioni genetiche che intercorrono tra questi e i caratteri legati allâaccrescimento.
I contenuti di androstenone (AND), scatolo (SCA) e indolo (IND) sono stati quantificati tramite cromatografia liquida ad alta prestazione in microcampioni di tessuto adiposo prelevati in-vivo dalla regione del collo di 500 suini maschi interi della linea C21 al raggiungimento dellâetĂ di 160 e 220 giorni. Inoltre, per 100 di essi, i composti sono stati quantificati anche in un campione di grasso di copertura della coscia prelevato in sede di macellazione.
Le concentrazioni dei tre composti misurati nel grasso di animali di 220 giorni sono risultati superiori a quelli riscontrati a 160 giorni di etĂ , cosĂŹ come la percentuale di campioni che superano i limiti di accettabilitĂ utilizzati per discriminare le carcasse affette o meno dallâodore di verro. Questo suggerisce che lâincidenza del problema dellâodore di verro Ăš maggiore nei suini piĂč pesanti e maturi da un punto di vista sessuale. Inoltre, unâelevata correlazione Ăš stata riscontrata tra il contenuto di AND, SCA e IND nel grasso dorsale e nel grasso di copertura delle cosce, suggerendo che il problema puĂČ essere rilevante anche nei prosciutti crudi DOP. I composti responsabili dellâodore di verro hanno mostrato unâelevata ereditabilitĂ ad entrambe le etĂ , confermando che la selezione genetica potrebbe essere una valida soluzione per ridurre lâodore di verro anche in suini macellati a pesi elevati. Le correlazioni genetiche tra AND, SCA e IND misurati alle due diverse etĂ sono risultate di grado moderato o elevato. Tuttavia, sono state riscontrate delle differenze nelle classifiche dei candidati riproduttori quando i fenotipi misurati alle due diverse etĂ sono stati usati per la stima dei EBV. Infine, le correlazioni genetiche tra AND, SCA e IND e caratteri legati allâaccrescimento sono risultate modeste, suggerendo che la riduzione della concentrazione di questi composti nel tessuto adiposo tramite selezione genetica non dovrebbe influenzare le prestazioni di crescita in suini non castrati.
Nella seconda parte di questa tesi Ăš stato esaminato in contributo degli effetti sociali sulla variabilitĂ di caratteri legati alla qualitĂ della carcassa e della coscia in suini pesanti. Le attuali procedure di valutazione genetica della linea C21 non tengono in considerazione lâinfluenza che il genotipo di un animale ha sul fenotipo dei suoi compagni di gruppo (effetto sociale). Se presenti, gli effetti sociali contribuiscono alla varianza ereditabile e quindi possono influenzare la risposta alla selezione. Lo studio si Ăš quindi proposto di stimare le componenti di varianza per il peso a 270 giorni di etĂ (PESO270), caratteri di qualitĂ della carcassa e della coscia utilizzando modelli genetici âclassiciâ e modelli competitive (che includono gli effetti sociali), nonchĂ© determinare la bontĂ dellâadattamento ai dati di questi modelli.
Lo studio Ăš stato condotto su 9,871 suini ibridi Goland allevati in gruppi contenenti da 4 a 7 individui, con dimensione media del gruppo pari a 6.1 suini. Quindi, quattro modelli sequenziali sono stati utilizzati per la stima delle componenti di varianza.
Il confronto dei modelli ha rivelato che il modello competitive mostra un miglior adattamento ai dati rispetto ad un modello che considera solo gli effetti genetici additivi per il PESO270, la percentuale di carne magra in carcassa (CM), il numero di iodio, la globositĂ e lo spessore del grasso sottocutaneo misurati sulla coscia. Gli effetti sociali contribuiscono in modo considerevole alla varianza ereditabile per il PESO270 e CM, mentre hanno un effetto meno rilevante per gli altri caratteri esaminati. La correlazione tra la componente genetica additiva e quella sociale Ăš risultata negativa per i caratteri legati alla qualitĂ della carcassa e della coscia, causando una diminuzione della varianza ereditabile sfruttabile per la selezione di questi caratteri. In conclusione, lo studio ha dimostrato che gli effetti sociali contribuiscono alla variabilitĂ di caratteri rilevanti nel suino pesante destinato alla produzione dei prosciutti crudi DOP e, quindi, le attuali procedure per la valutazione genetica della linea C21 dovrebbero includere anche la componente sociale.
La terza parti della tesi ha riguardato lo studio di nuove procedure di valutazione genetica basate sulla selezione genomica (SG). Lâobiettivo Ăš quello di migliorare la predizione dei EBV per caratteri importanti nel suino pesante superando alcune delle criticitĂ dellâattuale sistema di valutazione genetica della linea C21 basato su un programma di sib-testing.
In un primo lavoro, sono state studiate procedure di SG basate sulla metodologia single-step BLUP (SSBLUP). Le informazioni fenotipiche per caratteri riguardanti la qualitĂ della carcassa e della coscia sono state registrate in 11,488 suini ibridi Goland. Per 1,878 animali sono stati inoltre rilevati i cali di peso della coscia durante le diverse fasi di trasformazione in prosciutto crudo. Allo scopo di costituire la popolazione di riferimento per lo sviluppo dellâequazione di predizione dei breeding values genomici (GEBV), 1,088 soggetti ibridi, 136 verri nucleo di linea C21 (C21_VN) e 500 soggetti C21 mezzi fratelli degli animali ibridi (C21_MF) sono stati genotipizzati per 8,826 polimorfismi a singolo nucleotide utilizzando il DNA chip GGP Porcine LD Chip. La valutazione genetica tradizionale Ăš stata condotta sfruttando la metodologia BLUP, mentre la valutazione genomica si Ăš basata su un approccio SSBLUP. Lâequazione di predizione dei GEBV Ăš stata validata utilizzando i 500 C21_MF con genotipo come popolazione di validazione. La valutazione genetica tradizionale e quella genomica sono state confrontate tra loro attraverso la correlazione tra EBV e GEBV (r_(EBV,GEBV)). Elevati coefficienti di correlazione tra EBV e GEBV sono stati osservati sia per i soggetti ibridi genotipizzati che per gli individui C21_VN, suggerendo che le stime dei GEBV sono simili a stime accurate dei EBV ottenute con metodi tradizionali. Per quanto concerne i soggetti inclusi nella popolazione di validazione, r_(EBV,GEBV) sono risultate di entitĂ minore rispetto ai due gruppi considerati in precedenza. Differenze nelle classifiche dei candidati riproduttori sono state osservate quando esse erano basate sui EBV piuttosto che sui GEBV. Tali differenze sono attribuibili allâabilitĂ della metodologia SSBLUP di stimare GEBV individuali, anzichĂ© EBV identici per soggetti che appartengono alla stessa famiglia di fratelli pieni (quando essi hanno informazione genomica). Quindi lâutilizzo di un approccio di SG permette di scegliere i soggetti migliori in base a meriti genetici individuali piuttosto che âfamiliariâ, limitando il tasso di consanguineitĂ e aumentando lâaccuratezza della selezione. Inoltre, i risultati ottenuti rivelano che lâimplementazione di procedure di SG nel programma di selezione della linea C21 consentirebbero di introdurre tra gli obiettivi di selezione anche caratteri di difficile misurazione.
Come descritto in precedenza, gli effetti sociali contribuiscono alla variabilitĂ di caratteri rilevanti per il suino pesante e che modelli competitive forniscono un miglior adattamento ai dati per i caratteri PESO270, CM, il numero di iodio, la globositĂ e lo spessore del grasso sottocutaneo misurati sulla coscia. Quindi, per questi caratteri, sono state analizzate procedure di SG basate sulla metodologia SSBLUP che consideravano, oltre agli effetti genetici diretti, anche gli effetti sociali. Le informazioni fenotipiche e genomiche utilizzate sono le medesime descritte per il precedente studio. Differenze nelle classifiche degli animali inclusi nella popolazione di validazione sono state riscontrate sia quando esse erano basate su EBV e GEBV riferiti alla sola componente genetica diretta, c
Validation of a high liquid chromatography method (HPLC) for simultaneous quantification of skatole and indole in porcine fat
Boar taint is a meat quality defect that may lead to an unpleasant experience during the consumption of meat and meat products with negative economic repercussions for food industry. It can occur when meat or fat from entire male pigs is heated, due to excessive accumulation of skatole, indole and androstenone (1). For a fast identification and quantification of skatole and indole, an high-pressure liquid chromatography analytical method, coupled with a fluorimetric detector (HPLC-FD), has been set up and validated. The extraction of the target analytes (skatole, indole and internal standard, 2-methylindole) from lipid matrix (approximately 0.5 ± 0.05 g of subcutaneous fat taken from female pigs at slaughterhouse) was performed by sample liquefaction, addition of pure methanol and separation of the organic solvent was obtained by cooling and centrifugation steps (2). Chromatography separation was achieved using a simple isocratic HPLC method (3). In addition to the limit of detection (LOD) and quantification (LOQ), linearity, recovery, accuracy and sensitivity were evaluated for the validation of the method. A good linearity was confirmed by the correlation coefficient (R2) of the standards calibration curves always ℠0,99, together with the recovery from matrix for both analytes, always ℠96%. The precision of the method, intra-and inter-assay, expressed as relative standard deviation (RDS%) was good for each analyte, always below the limit of 10%. Good results were obtained also for LOD and LOQ, amounting to 1,562 ng/g and 2,312 ng/g for both compounds, concentrations far lower than those perceived by human smell. The proposed method is suited for rapid routine analyses because of its high sensitivity and precision, required by small sample size and was always reliable to identify and quantify target compounds in all samples analyzed. The follow application of the method to samples (28) taken at slaughterhouse by different subjects (sows, entire and castrated male), has allowed always to identify and quantify skatole and indole, confirming the robustness of the method. The small sample size of sample used, allow the application of the method also to samples of fatty tissue taken from pigs by subcutaneous biopsy
Effects of variation in milk coagulation properties on cheese yield, curd composition and recovery rates of the main milk constituents measured by micro-cheese making.
Direct and social effects on variation of carcass and ham quality traits in Italian heavy pigs.
Separation and quantification of water buffalo milk protein fractions and genetic variants by RP-HPLC
International audienc
Separation and quantification of water buffalo milk protein fractions and genetic variants by RP-HPLC.
A RP-HPLC method, developed for the separation and quantification of the most common genetic variants of bovine milk proteins, was successfully applied to the analysis of water buffalo milk. All the most common buffalo casein and whey proteins fractions, as well as their genetic variants, were detected and separated simultaneously in 40 min. Purified buffalo proteins were used as calibration standards and a total of 536 individual milk samples were analysed for protein composition. \u3b1(S1)-, \u3b1(S2)-, \u3b2\u3b3-, and \u3ba-casein were 32.2%, 15.8%, 36.5%, and 15.5%, respectively, of total casein content, whereas content of \u3b2-Lactoglobulin was approximately 1.3 times as high as that of \u3b1-Lactalbumin. The existence of a polymorphism of \u3ba-casein was demonstrated in Mediterranean water buffalo and \u3b1(S1)- and \u3ba-casein genetic variants were successfully detected by RP-HPLC