CLA induced milk fat depression reduced dry matter intake and improved energy balance in dairy goats

Abstract

The extent to which CLA supplements inhibit milk fat synthesis is highly dependent on the amount of trans-10, cis-12 CLA reaching the mammary gland. Secondary events such as changes in milk yield, dry matter intake (DMI), body weight (BW) and energy balance (EB) may also occur depending on the magnitude of milk fat depression. This study investigated the effects of feeding a rumen unprotected CLA methyl ester supplement on milk fat yield and fatty acid (FA) profile, yield of milk and other milk components, DMI and metabolic variables in dairy goats. Twenty primiparous, non-pregnant Toggenburg goats, paired by BW, days in milk (DIM) and milk yield (MY) [2.8 ± 0.4 (mean ± SEM) kg milk/day, BW of 40 ± 3.7 kg and 75 ± 3 days in milk] were used in a crossover design with 14 days treatment periods and a 6 days washout. Goats were randomly assigned to the following treatments: Control (30 g/day of calcium salts of FA) or CLA [30 g/day of a rumen unprotected CLA methyl ester supplement (29.9% trans-10, cis-12 CLA)]. There was no treatment effect on BW, milk yield, or milk protein and lactose content and yield. However, compared to Control, CLA decreased milk fat content and yield by 13.9 and 13.3%, respectively, and CLA treated goats consumed 6.5% less corn silage. The CLA treatment increased the concentration of both CLA isomers (cis-9, trans-11 and trans-10, cis-12) in milk fat. The concentration of short and medium chain milk FA (C16) was decreased by CLA, while long chain FA were increased. However, the daily secretion was lower for FA of all chain lengths in CLA treated goats. Glucose and insulin were not affected by treatment, while CLA treatment decreased non esterified FA by 22.2%. The CLA treatment improved calculated EB by 0.3 Mcal/day. Overall, CLA methyl ester supplements are effective in causing milk fat depression in lactating dairy goats and improving EB, which may be used as a nutritional tool in some circumstances.

Composition, Mineral and Fatty Acid Profiles of Milk from Goats Fed with Different Proportions of Broccoli and Artichoke Plant By-Products

“…The desaturation indices obtained in this experiment are similar to those provided by Baldin et al Ref. [58] in a study in goats that received a dietary CLA supplement.…”

Trans10, cis12 conjugated linoleic acid increases triacylglycerol accumulation in goat mammary epithelial cells in vitro

“…Data using exogenous t10c12-CLA support the view that it is the main trans-fatty acid resulting in milk fat depression in dairy cattle (Baumgard et al 2002). The effects of t10c12-CLA on milk-fat and body-fat reduction were also demonstrated in several species such as mice (Park et al 1999;Brown et al 2004;Baldin et al 2014). Because few studies have been performed with t10c12-CLA in small ruminants, the detailed mechanisms of t10c12-CLA on milk fatty acid metabolism in dairy goats is not totally understood.…”

“…t10c12-CLA was reported to result in a marked depression in milk fat when its concentration increased in dairy goats (Lock et al 2008), and it inhibited the short-to-medium chain fatty acid synthesis as well as increased the content of long-chain fatty acids (LCFAs) (Baldin et al 2014). The molecular mechanisms underlying those responses in goat mammary gland remain to be determined.…”

trans-10,cis-12 conjugated linoleic acid alters lipid metabolism of goat mammary epithelial cells by regulation of de novo synthesis and the AMPK signaling pathway

“…Lipid metabolism is an important process in the mammary gland and can be regulated by nutritional factors, especially fatty acids (Peterson et al, 2004;Bernard et al, 2005). The effects of t10c12-CLA on milk fat content and composition are well established in several mammals (Hussein et al, 2013;Baldin et al, 2014;Harvatine et al, 2014). In addition to regulating milk fat, t10c12-CLA has been shown to reduce triglyceride storage, enhance fatty acid oxidation, and diminish glucose uptake and utilization in murine adipocytes (den Hartigh et al, 2013).…”