A rumen unprotected conjugated linoleic acid supplement inhibits milk fat synthesis and improves energy balance in lactating goats1

Abstract

Feeding trans-10, cis-12 CLA supplements in a rumen-protected form has been shown to cause milk fat depression (MFD) in cows, ewes, and goats. Methyl esters of CLA were shown to be as effective as FFA in inducing MFD when infused postruminally, but their efficacy as a feed supplement has not been addressed in studies with lactating ruminants. In the present study, we investigated the effects of an unprotected trans-10, cis-12 CLA supplement as methyl esters on performance, milk composition, and energy status of dairy goats. Eighteen multiparous Toggenburg goats were randomly assigned to dietary treatments in a crossover experimental design (14 d treatment periods separated by a 7 d washout interval): 30 g/d of calcium salts of fatty acids (Control) or 30 g/d of a rumen unprotected CLA supplement containing 29.9% of trans-10, cis-12 CLA as methyl esters (CLA). Lipid supplements were mixed into a concentrate and fed individually to animals 3 times a day as a total mixed ration component. The DMI, milk yield, milk protein and lactose content and secretion, and somatic cell count were unaffected by CLA treatment. On the other hand, milk fat content and yield were reduced by 19.9 and 17.9% in CLA-fed goats. Reduced milk fat yield in CLA-fed goats was a consequence of a lower secretion of both preformed and de novo synthesized fatty acids. The CLA treatment also changed the milk fatty acid profile, which included a reduction in the concentration of SFA (2.5%), increased MUFA and PUFA (5.6 and 5.4%, respectively), and a pronounced increase (1576%) in milk fat trans-10, cis-12 CLA. Consistent with the high milk fat trans-10, cis-12 CLA content, all desaturase indexes were reduced in milk fat from CLA-fed goats. The MFD induced by CLA reduced the energy required for milk production by 22%, which was accompanied by an improvement in the estimated energy balance (P < 0.001), greater blood glucose concentration (P < 0.05), and a trend for increased BW (P = 0.08). Approximately 7.2% of trans-10, cis-12 CLA was estimated to escape from rumen biohydrogenation and indirect comparisons with data obtained from other studies suggest equivalent MFD between dietary CLA in the methyl ester form and rumen protected sources. Thus, despite the apparent low degree of rumen protection, our results suggest that methyl esters of CLA could be an alternative to rumen protected CLA supplements due to manufacturing and cost advantages.

Transcriptional regulation of acetyl-CoA carboxylase α isoforms in dairy ewes during conjugated linoleic acid induced milk fat depression

“…The CLA supplement consisted of FA methyl esters with the following composition: 4.1% palmitic acid, 3.6% stearic acid, 27.4% oleic acid, 1.2% linoleic acid, 29.8% cis-9, trans-11 CLA, 29.9% trans-10, cis-12 CLA and 3.0% other FA. This CLA supplement has been reported to induce MFD and change the milk FA profile in sheep by Oliveira et al (2012) and Baldin et al (2013a), and in goats by Baldin et al (2013b and and Fernandes et al (2014). In addition, de Veth et al (2004) reported that abomasally infused CLA methyl esters had equal potency in inhibition of milk fat synthesis compared with CLA in the free FA form.…”

Tithonia diversifolia as a Supplementary Feed for Dairy Cows

“…The organic phase containing the milk fat (~20 mg) was evaporated to dryness at 40°C under oxygen-free nitrogen. Fatty acid methyl esters (FAME) were obtained by base-catalyzed transmethylation as described in detail by Baldin et al [18]. Fatty acid methyl esters were quantified by a gas chromatograph (model 7820-A, Agilent Technologies) fitted with a flame-ionization detector and equipped with a CP-Sil 88 fused-silica capillary column (100 m × 0.25 mm × 0.2 μm film thickness; Varian Inc).…”

“…Operating conditions were set as described by Cruz-Hernandez et al [19]. The FAME were identified by comparison of retention times with commercial FAME standards; minor trans/cis-C18:1 isomers and trans-9 cis-11 CLA were identified according to their order of elution reported under the same GC conditions [18]. Milk fatty acid composition was expressed as a weight percentage of total fatty acids using theoretical relative response factors [20].…”

Perfil de ácidos graxos do leite de vacas Holandês x Gir em pastagem de capim-marandu suplementado com quantidades crescentes de grão de soja tostado

“…Zootec., v.67, n.4, p.1150-1158, 2015 ao perfil de AG, por cromatografia em fase gasosa, conforme procedimentos descritos por Perez et al (2010). No 11 o dia de cada fase dos QLs, foram coletadas em frascos sem conservantes amostras representativas da produção individual diária de leite (2/3 na ordenha da manhã + 1/3 na ordenha da tarde), que foram congeladas a -10 o C, visando analisar o perfil de AG, realizado por cromatografia em fase gasosa, segundo os procedimentos descritos por Baldin et al (2013). Os índices de aterogenicidade (IA) e de trombogenicidade (IT) e as relações entre os AG ômega 6:ômega 3 (ω-6:ω-3) e AG hipo:hipercolesterolêmicos (h/H) foram utilizados para avaliar a qualidade nutricional da gordura do leite (Barros et al, 2013).…”