Effect of abomasal infusions of a mixture of octadecenoic acids on milk fat synthesis in lactating cows

Abstract

Diets causing milk fat depression (MFD) are known to alter ruminal lipid metabolism leading to the formation of specific biohydrogenation intermediates that exert antilipogenic effects. Several isomers of conjugated linoleic acid (CLA), namely trans-10, cis-12 CLA, cis-10, trans-12 CLA, and trans-9, cis-11 CLA, inhibit mammary lipogenesis in the lactating cow, but ruminal outflow of these biohydrogenation intermediates does not account entirely for the reductions in milk fat synthesis during diet-induced MFD. Milk fat trans-10 18:1 concentrations are consistently increased on diets that cause MFD, suggesting a possible role in the regulation of milk fat secretion. Three rumen-fistulated cows in mid lactation were used in a 3 x 3 Latin square to evaluate the effects of a mixture of 18:1 fatty acid methyl esters (FAME) on milk fat synthesis. Experimental treatments consisted of abomasal infusions of ethanol (control), 6 g/d of trans-10, cis-12 CLA (positive control; CLA), or 247 g/d of a mixture of 18:1 FAME containing (% fatty acids) cis-9 (9.45), cis-12 (3.35), trans-10 (37.3), trans-11 (37.4), and trans-12 (2.66) as major isomers (T181 treatment). Administration of the T181 treatment supplied 92.1 g/d of trans-10 18:1. Infusions were conducted over a 5-d period with a 9-d interval between treatments. Treatments had no effect on dry matter intake, milk yield, or milk protein. Relative to the control, abomasal infusion of T181 and trans-10, cis-12 CLA treatments reduced milk fat secretion by 19.5 and 41.5%, respectively. Even though a direct cause and effect on mammary lipogenesis could not be established, comparisons with published data and considerations of the relative abundance of constituent FAME in treatment T181 implicated trans-10 18:1 as the isomer responsible. In conclusion, current data suggest that trans-10 18:1 potentially exerts antilipogenic effects and may contribute to the reduction in milk fat synthesis during diet-induced MFD in the lactating cow.

Production performance and pattern of milk fat depression of high-yielding dairy cows supplemented with encapsulated conjugated linoleic acid

“…It was also proposed by Piperova et al (2004) that trans-10 18:1 might independently be involved in MFD. In a report by Lock et al (2007), abomasal infusion of 42.6 g of trans-10 18:1/day had no effect on milk fat secretion; however, in a recent study by Shingfield et al (2009), higher amount of trans-10 18:1/day (92.1 g/day) abomasal infusion resulted in 21.3% and 19.5% reductions in milk fat content and yield, respectively.…”

Metabolism of conjugated linoleic acids and 18 : 1 fatty acids by ruminal bacteria: products and mechanisms

“…Although the concentrations of cis-9,trans-11-18 : 2 and trans-10,cis-12-18 : 2 prevented growth of B. proteoclasticus, previous reports Maia et al, 2007) using lower fatty acid concentrations tend to suggest that B. proteoclasticus is capable of converting CLA to 18 : 1 fatty acids in the same manner as B. fibrisolvens. Furthermore, trans-10,cis-12-18 : 2, which is known to exert antilipogenic effects in lactating ruminants (Lock et al, 2006;Shingfield & Griinari, 2007;Shingfield et al, 2009), is not metabolized further by the producing species, P. acnes, but is converted by Butyrivibrio spp. to a mixture of trans-10-18 : 1, trans-12-18 : 1 and cis-12-18 : 1.…”

“…The same is usually true in the mixed ruminal ecosystem, but under certain conditions trans-10-18 : 1 is formed via the reduction of trans-10,cis-12-18 : 2 or from the isomerization of cis-9-18 : 1 and represents the major biohydrogenation intermediate of the mixed ruminal ecosystem in vivo (Shingfield & Griinari, 2007). Post-ruminal infusion experiments have established that trans-10,cis-12-18 : 2 exerts anti-lipogenic effects in the lactating cow (Baumgard et al, 2000;Saebø et al, 2005;Lock et al, 2006), with recent studies suggesting that trans-10-18 : 1 may also decrease mammary lipogenesis (Shingfield et al, 2009). Our studies indicate that Propionibacterium acnes may be responsible for the formation of trans-10,cis-12-18 : 2 .…”

Effects of polyunsaturated fatty acids from plant oils and algae on milk fat yield and composition are associated with mammary lipogenic and SREBF1 gene expression

“…These data, together with others combining plant oils with FO (Whitlock et al, 2002;AbuGhazaleh et al, 2004) underlined that MFD may occur with moderate increase (Whitlock et al, 2002;AbuGhazaleh et al, 2004) or without increasing (Invernizzi et al, 2010) milk trans-10,cis-12-CLA. Thus, the implication of other biohydrogenation intermediates have been involved, such as trans-18:1 isomers and specifically the trans-10 18:1 isomer, which may exert potentially antilipogenic effects and contribute to the reduction in milk fat synthesis during diet-induced MFD in the lactating cow (Shingfield et al, 2009). In addition, the trans-9,cis-11-CLA and the cis-10,trans-12-CLA isomers, have been also identified as inhibitors of milk fat synthesis (Shingfield et al, 2010), but their outputs were very low in the present experiment.…”