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Ruminants derived products have a prominent role in diets and economy worldwide; therefore, the capability to control the rumen microbial ecosystem, for ameliorating their quality, is of fundamental importance in the livestock sector. The aim of this study was to evaluate the effect of dietary supplementation with chestnut and quebracho tannins on microbial community and fatty acid profile, in the rumen fluid of dairy ewes. Multivariate analysis of PCR-DGGE profiles of rumen microbial communities showed a correlation among the presence of chestnut or quebracho in the diet, the specific Butyrivibrio group DGGE profiles, the increase in 18:3 cis9, cis12, and cis15; 18:2 cis9 and cis12; 18:2 cis9 and trans11; 18:2 trans11 and cis15; and 18:1 trans11 content, and the decrease in 18:0 concentration. Phylogenetic analysis of DGGE band sequences revealed the presence of bacteria representatives related to the genera Hungatella, Ruminococcus, and Eubacterium and unclassified Lachnospiraceae family members, suggesting that these taxa could be affected by tannins presence in the diets. The results of this study showed that tannins from chestnut and quebracho can reduce the biohydrogenation of unsaturated fatty acids through changes in rumen microbial communities. [ABSTRACT FROM AUTHOR]

An in vitro trial was carried out to study the effects of Quebracho tannins extract (QE) on fatty acid profile of rumen solid adherent bacteria (SAB) during the fermentation of diets supplemented with soybean or linseed oil, as sources of linoleic (LA; 18:2 n-6) and α- linolenic acid (α-LNA; 18:3 n-3), respectively. Two control diets were prepared using a basal mixture of grass hay [760 g/kg on dry matter (DM)], soybean meal (55 g/kg DM), barley meal (130 g/kg DM), vitamin mineral premix (20 g/kg DM) and 35 g/kg DM of soybean (SOC diet) or linseed oil (LOC diet) as lipid supplement. Other two diets (SOCT and LOCT) were obtained by integrating SOC and LOC with QE (49 g/kg DM). The results confirmed that Quebracho tannins may be an effective method for reducing in SAB the biohydrogenation of LA (17.3 vs 34.5 g/100 g of fatty acid in SOC and SOCT, respectively) and LNA (10.7 vs 21.4 g/100 g of fatty acid in LOC and LOCT, respectively), but not for increasing the rumen accumulation of cis9, trans11 18:2 (0.77 vs 0.32 g/100 g of fatty acid in SOC and SOCT, respectively; 0.51 vs 0.43 g/100 g of fatty acid in LOC and LOCT, respectively) and trans11 18:1 (6.15 vs 3.64 g/100 g of fatty acid in SOC and SOCT, respectively; 5.53 vs 4.47 g/100 g of fatty acid in LOC and LOCT, respectively). [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the evolution of the fatty acid profile, with particular attention to conjugated linoleic acid (CLA) and to C18:1 isomers, during ripening of sheep cheese (Pecorino Toscano cheese) produced with raw milk. After 60 days of ripening the total concentration of C18:1 isomers and that of CLA pool content decreased. In particular, if isomers profile is considered, the percentage of trans11 C18:1, trans10 C18:1 and cis9, trans11 CLA decreased as consequence of biohydrogenation or of double bonds isomerisation, while the concentration of trans10, cis12 CLA increased. [ABSTRACT FROM AUTHOR]

Cheese quality traits are affected firstly by milk quality and secondly by processing protocols. The cheese-making procedure plays an important role in the transfer of functional fat components from milk to cheese with important implications on the nutritive value of dairy products. To evaluate the influence of the cheese-making procedure, three fresh Italian cheeses from the same milk bulk, Mozzarella, Raveggiolo and Ricotta were processed and analyzed in terms of fatty acid transfer from milk to dairy products. The fatty acids were transferred with several differences. In particular, C14:0 (P = 0.0011) and C14:1 (P = 0.0007) showed the highest value in Raveggiolo while C16:0 was higher in Raveggiolo and Ricotta (P = 0.0002). Trans -monoene fatty acids have a detrimental effect on human health, however trans C18:1 isomers, from 6 to 10, and trans12 showed no significant differences in transfer from milk to dairy products. In contrast, vaccenic and linoleic acids, which are beneficial fatty acids for human health, were recovered in higher percentages in Raveggiolo than in Mozzarella and Ricotta (P = 0.0188 and P < 0.0001, respectively). The recovery of oleic acid, an antiatherogenic fatty acid, was higher in Ricotta (P < 0.0001). No effect on conjugated linoleic acid was found. • Dairy products contain fatty acids recognised beneficial for human health. • The cheese-making procedure affects the quality of cheeses, especially of fresh ones. • The transfer of functional fatty acids from milk to cheeses is affected by cheese-making procedure. [ABSTRACT FROM AUTHOR]