Sicily has one of the richest heritages of animal biodiversity of Italy. The dairy sector is characterized by many typical products, often related to breeds and indigenous cows, to feeding techniques that make extensive use of grazing and traditional cheese-making techniques. Dairy cattle breeds have been subjected to an intensive selection towards improvement of milk production traits. Milk composition is very variable, being conditioned by the complex metabolic activity linked to individual variability of animals, to nutritional and environmental factors. In the present study, it was investigated for the first time in Modicana breed, novel information about polymorphisms at key genes involved in lipid metabolism and interaction between these polymorphisms and the feeding systems. It was studied how the presence of pasture in the diet can interfere with the effects of polymorphisms at the studied loci on milk yield, gross composition and fatty acid profile. Modicana cows reared in two farms of the Ragusa province with an extensive and semi-intensive system were characterized under the genetic profile for the lipogenic polymorphisms (ABCG2-Y581S, DGAT1-K232A, STAT5A-V686A, SCD1-A293V). Subsequently, on the basis of the genotypes detected, 36 and 38 cows were selected from the semi-intensive and extensive systems, respectively. From these animals, individual phenotypic data were collected relative to productivity, milk composition, fatty acid profile and mineral composition, in order to evaluate the effect of the genetic polymorphisms and interaction with feeding systems on the quantitative and qualitative characteristics of milk. The entire population resulted monomorphic at ABCG2 Y581S polymorphism while for the other loci the allele with higher frequency were: 91% for GC (232A) at DGAT1, 68% for T (686V) at STAT5A and 73% for T (293A) at SCD1. Feeding system influenced milk yield and protein content that resulted higher in animals fed with natural pasture while, when feeding systems were considered in interaction with the polymorphisms, results do not allow to find significant differences within the different phenotypes in milk in both systems, extensive and semi-intensive. Feeding system also affected milk FAs composition and animals reared in an extensive system, showed a lower content of SFA and a higher fraction of MUFA, PUFA and trans FAs. Then, considering the interaction between the feeding systems and the polymorphisms on milk FAs composition, results showed that some FAs were significant affected by this interaction. The DGAT1-K232A polymorphism in interaction with feeding system, affected the content of C4, CLA and C22:4. Milk of animals with DGAT1 GC/GC genotype (232A) and fed with pasture showed a higher content of CLA. The STAT5A-V686A polymorphism affected OBCFA composition, the content of which resulted higher in animals with TT genotype (686V). Animals with TT genotype showed also a higher content of C18:1t11, C18:1c9, C20:4 and C22:5n3 and a lower C20:5n3 content. No interaction has been detected between the identified genotypes and the feeding systems. The SCD1-A293V polymorphism in interaction with feeding systems affected the contents of C4, C6, C8, C18:1t11 and C20:3 that gradually decreased in animals reared in an extensive system from CC to heterozygous to TT genotype. Finally, regarding mineral composition, the only significant effect was reported for the K content that was associated with STAT5A-V686A polymorphism and resulted higher in heterozygous animals. This study described that relationship between the polymorphisms at lipogenic loci and feeding systems in Modicana cows affected some milk production traits but further research are required to describe and better understand the variations in milk traits, within and between the breeds, not only through a genetic or nutritional point of view but as a dynamic interaction between these two aspects.
La Sicilia presenta uno dei piu ricchi patrimoni di biodiversità animale d'Italia. Il settore lattiero-caseario è caratterizzato da molti prodotti tipici, spesso legati a razze e popolazioni autoctone, ai sistemi di allevamento e caseificazione. I bovini da latte sono stati sottoposti ad una intensa selezione verso il miglioramento della produzione lattifera. Nel presente studio sono state indagate, per la prima volta nella razza Modicana, nuove informazioni riguardo i polimorfismi in alcuni geni coinvolti nel metabolismo dei lipidi ed è stata presa in considerazione l'interazione tra questi polimorfismi e i sistemi di allevamento e l’influenza di questa sulla composizione del latte. Nello specifico, come il pascolo influenza gli effetti dei polimorfismi ai loci analizzati, sulla produzione, composizione del latte e profilo degli acidi grassi. I bovini di razza Modicana considerati, sono allevati in due aziende della provincia di Ragusa secondo un sistema estensivo e semi-intensivo. Gli animali sono stati caratterizzati sotto il profilo genetico per i polimorfismi ai seguenti loci lipogenici: ABCG2-Y581S, DGAT1-K232A, STAT5A-V686A e SCD1-A293V. In base ai genotipi individuati, sono stati selezionati 36 e 38 animali allevati rispettivamente secondo il sistema semi-intensivo ed estensivo. Sugli animali selezionati, sono stati raccolti i dati fenotipici relativi alla produttivita , composizione del latte, minerali e profilo degli acidi grassi, al fine di valutare l'effetto dei polimorfismi e l'interazione con i sistemi di allevamento sulle caratteristiche quanti-qualitative del latte. Tutta la popolazione è risultata monomorfa per il polimorfismo Y581S al locus ABCG2 mentre per gli altri loci, gli alleli con piu alta frequenza sono: 91% per GC al locus DGAT1 (232A), 68% per T al locus STAT5A (686V) e 73% per T al locus SCD1 (293A). Il sistema di allevamento ha influenzato significativamente la produzione di latte e il contenuto di proteine che sono risultati più elevati negli animali alimentati al pascolo. Quando il sistema di allevamento è stato considerato in relazione ai polimorfismi, i risultati non hanno mostrato differenze significative all'interno dei diversi fenotipi in entrambi i sistemi. Il sistema di allevamento ha influenzato anche la composizione degli acidi grassi. Gli animali alimentati al pascolo hanno mostrato un minor contenuto di SFA e una maggiore frazione di MUFA, PUFA e acidi grassi trans. Il polimorfismo K232A al locus DGAT1 in interazione con il sistema di allevamento ha influenzato il contenuto di C4:0, CLA e C22:4. Il latte di animali con genotipo GC/GC al locus DGAT1 e alimentati al pascolo, hanno mostrato un più alto contenuto di CLA. Il polimorfismo V686A al locus STAT5A ha influenzato la composizione degli OBCFA il cui contenuto è risultato più elevato negli animali con genotipo TT che hanno anche mostrato un maggior contenuto di C18:1t11, C18:1c9, C20:4 e un più basso contenuto di C20:5n3. Nessuna interazione è stata rilevata quando il polimorfismo è stato considerato in relazione al sistema di allevamento. Il polimorfismo A293V al locus SCD1 in interazione con il sistema di allevamento ha influenzato il contenuto di C4:0, C6:0, C8:0, C18:1t11 e C20:3 negli animali allevati con il sistema estensivo che è diminuito passando dal genotipo CC a quello TT. Riguardo alla composizione minerale, l'unico effetto significativo è stato riportato per il contenuto di K associato al polimorfismo V686A al locus STAT5A il cui contenuto è risultato maggiore negli animali eterozigoti. Questo studio ha dimostrato l'esistenza di una relazione tra i polimorfismi ad alcuni loci lipogenici e i sistemi di allevamento che ha influenzato alcuni tratti della produzione del latte in bovine di razza Modicana. Ulteriori ricerche sono necessarie per descrivere e comprendere al meglio queste relazioni, non solo da un punto di vista genetico o nutrizionale, ma come interazione dinamica tra questi.
Genetic polymorphisms at lipogenic loci in Modicana cows: effects on milk production traits in different feeding systems / Moltisanti, Valentina. - (2016 Dec 09).
Genetic polymorphisms at lipogenic loci in Modicana cows: effects on milk production traits in different feeding systems
MOLTISANTI, VALENTINA
2016-12-09
Abstract
Sicily has one of the richest heritages of animal biodiversity of Italy. The dairy sector is characterized by many typical products, often related to breeds and indigenous cows, to feeding techniques that make extensive use of grazing and traditional cheese-making techniques. Dairy cattle breeds have been subjected to an intensive selection towards improvement of milk production traits. Milk composition is very variable, being conditioned by the complex metabolic activity linked to individual variability of animals, to nutritional and environmental factors. In the present study, it was investigated for the first time in Modicana breed, novel information about polymorphisms at key genes involved in lipid metabolism and interaction between these polymorphisms and the feeding systems. It was studied how the presence of pasture in the diet can interfere with the effects of polymorphisms at the studied loci on milk yield, gross composition and fatty acid profile. Modicana cows reared in two farms of the Ragusa province with an extensive and semi-intensive system were characterized under the genetic profile for the lipogenic polymorphisms (ABCG2-Y581S, DGAT1-K232A, STAT5A-V686A, SCD1-A293V). Subsequently, on the basis of the genotypes detected, 36 and 38 cows were selected from the semi-intensive and extensive systems, respectively. From these animals, individual phenotypic data were collected relative to productivity, milk composition, fatty acid profile and mineral composition, in order to evaluate the effect of the genetic polymorphisms and interaction with feeding systems on the quantitative and qualitative characteristics of milk. The entire population resulted monomorphic at ABCG2 Y581S polymorphism while for the other loci the allele with higher frequency were: 91% for GC (232A) at DGAT1, 68% for T (686V) at STAT5A and 73% for T (293A) at SCD1. Feeding system influenced milk yield and protein content that resulted higher in animals fed with natural pasture while, when feeding systems were considered in interaction with the polymorphisms, results do not allow to find significant differences within the different phenotypes in milk in both systems, extensive and semi-intensive. Feeding system also affected milk FAs composition and animals reared in an extensive system, showed a lower content of SFA and a higher fraction of MUFA, PUFA and trans FAs. Then, considering the interaction between the feeding systems and the polymorphisms on milk FAs composition, results showed that some FAs were significant affected by this interaction. The DGAT1-K232A polymorphism in interaction with feeding system, affected the content of C4, CLA and C22:4. Milk of animals with DGAT1 GC/GC genotype (232A) and fed with pasture showed a higher content of CLA. The STAT5A-V686A polymorphism affected OBCFA composition, the content of which resulted higher in animals with TT genotype (686V). Animals with TT genotype showed also a higher content of C18:1t11, C18:1c9, C20:4 and C22:5n3 and a lower C20:5n3 content. No interaction has been detected between the identified genotypes and the feeding systems. The SCD1-A293V polymorphism in interaction with feeding systems affected the contents of C4, C6, C8, C18:1t11 and C20:3 that gradually decreased in animals reared in an extensive system from CC to heterozygous to TT genotype. Finally, regarding mineral composition, the only significant effect was reported for the K content that was associated with STAT5A-V686A polymorphism and resulted higher in heterozygous animals. This study described that relationship between the polymorphisms at lipogenic loci and feeding systems in Modicana cows affected some milk production traits but further research are required to describe and better understand the variations in milk traits, within and between the breeds, not only through a genetic or nutritional point of view but as a dynamic interaction between these two aspects.File | Dimensione | Formato | |
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