Effects of breed on milk fatty acid profile in dairy ewes, with particular reference to <i>cis-9, trans-11</i> conjugated linoleic acid

Abstract

________________________________________________________________________________ AbstractThe objective of this study was to determine and compare the fatty acid profile of milk fat, with particular reference to cis-9, trans-11 conjugated linoleic acid (CLA), in two indigenous Romanian sheep breeds (Spanca and Turcana), irrespective of the effects of diet and season. The ewes (n = 25 for each breed) received the same feed (total mixed rations) and were maintained under identical conditions. Four samples were collected from each individual ewe to determine fatty acids (FA), as methyl esters, using gas chromatography. The fatty acid groups, namely saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) acids were examined together with individual acids. Differences have been obtained between the two local breeds for the majority of FA. Fat in the milk of Turcana ewes has a healthier fatty acid profile than that of Spanca breed which has a lower concentration of SFA (60.9 vs. 73.3%) and higher concentrations of MUFA (31.0 vs. 21.0%) and PUFA (8.06 vs. 5.61%, respectively). Compared with the Spanca breed, fat in the milk of Turcana ewes had higher concentrations of trans-11 C18:1, C18:1 n9c, and cis-9 trans-11 CLA (2.67 vs. 1.01%, respectively). Δ 9 -desaturase activity is breed specific; vaccenic acid (trans-11 C18:1) desaturation and its conversion into cis-9, trans-11 CLA were more intense in the Turcana breed ewes. In conclusion, breed has a strong effect on the FA composition of ewe milk fat, and on cis-9, trans-11 CLA, in particular. The results obtained, support the sustainable use of animal genetic resources to improve the milk fat quality of ewes.________________________________________________________________________________

Assessment of lactation stage and breed effect on sheep milk fatty acid profile and lipid quality indices

“…standard error of mean, SFA saturated fatty acids, TI thrombogenic index, UFA unsaturated fatty acids, UFA/SFA unsaturated fatty acids/ saturated fatty acids, ω-6/ω-3 omega-6 fatty acids/omega-3 fatty acids ) in the same row represent significant differences between breeds with P<0.05 in *, with P<0.01 in ** and with P<0.001 in *** atherogenic index (AI) showed significantly (P < 0.05) higher values than the thrombogenic index (TI) in raw milk and cream fat (Tables 2 and 4). Therefore, atherogenic index values of sheep raw milk fat were found to be almost half of those reported by Nantapo et al (2014) for cow milk fat, similar to those reported by Soják et al (2013) for ewe milk fat and lower to those reported by Mierlita et al (2011) for Spanca ewe milk fat. The most interesting features in raw milk and cream fat, according to the above data, were the high proportions of short-and medium-chain fatty acids (SCFA and MCFA), as well as the existence of CLA isomers and PUFA even at low proportions.…”

“…In accordance with Signorelli et al's (2008) findings, FA profile could be proposed as an indicator of breed type. In the same sense, Mierlita et al (2011) reported that breed markedly affects the FA profile of ewe milk fat.…”

“…The effect of other factors in milk fat, such as breed or stage of lactation, has been much less studied. In recent years, several studies have investigated the effect of ewe breed on the milk fatty acid profile (Signorelli et al 2008;Talpur et al 2009;Mierlita et al 2011). To our knowledge, extensive analysis of fatty acid profile and lipid quality indices in raw milk and cream fat of indigenous breeds, which are kept in the same flock and receive the same management and diet in relation to their stage of lactation, has not been previously published.…”

Seasonal changes of the chemical composition of cheese obtained from the milk of indigenous Polish breeds of sheep

“…Tsiplakou et al (2006) and Signorelli et al (2008) did not find any significant effect of the breed on CLA in milk from different breeds of sheep maintained under the same feeding regimes, but this was due to the large variation in milk fat CLA content among individuals. When comparing the fatty-acid profile of milk from indigenous Romanian sheep breeds (Spanca and Turcana), Mierlita et al (2011) found differences for the majority of FA. The Turcana breed was characterized by lower SFA, and higher MUFA and PUFA contents.…”

Native and non native sheep breed differences in canestrato pugliese cheese quality: a resource for a sustainable pastoral system

“…The differences observed in the CLA content are very important because in the last years CLA has aroused much attention due to its anticarcinogenic activity, antiatherogenic, anti-obesity, anti-diabetes, and immune-stimulating properties (Crumb & Vattem 2011). Previous studies were focused mainly on the effect of sheep breed on the milk fatty acid profile (Signorelli et al 2008;Talpur et al 2009;Mierlita et al 2011), whereas the effect of breed on cheese quality was investigated to a lesser extent. Secchiari et al (2001) observed the breed effect (2014) is one of the few studies carried out simultaneously on milk and cheese made from different sheep breeds in Poland; they observed the breed effect on some isomers of CLA (CLA c9,t11;CLA t10,c12,and CLA c9,c11) in "oscypek" cheese manufactured from milk of different Polish breeds.…”