Milk fat depression and energy balance in stall-fed dairy goats supplemented with increasing doses of conjugated linoleic acid methyl esters

Abstract

Feeding dietary supplements containing trans-10, cis-12-conjugated linoleic acid (t10,c12-CLA) has been shown to induce milk fat depression in cows, ewes and goats. However, the magnitude of the response is apparently less pronounced in lactating goats. The objective of this study was to evaluate the effects of increasing doses of CLA methyl esters (CLA-ME) on milk production, composition and fatty-acid profile of dairy goats. Eight Toggenburg goats were separated in two groups (four primiparous and four multiparous) and received the following dietary treatments in a 4 × 4 Latin Square design: CLA0: 45 g/day of calcium salts of fatty acids (CSFA); CLA15; 30 g/day of CSFA + 15 g/day of CLA-ME; CLA30: 15 g/day of CSFA + 30 g/day of CLA-ME; and CLA45: 45 g/day of CLA-ME. The CLA-ME supplement (Luta-CLA 60) contained 29.9% of t10,c12-CLA; therefore, the dietary treatments provided 0, 4.48, 8.97 and 13.45 g/day of t10,c12-CLA, respectively. Feed intake, milk production, concentration and secretion of milk protein and lactose, body condition score and body weight were unaffected by the dietary treatments. Milk fat secretion was reduced by 14.9%, 30.8% and 40.5%, whereas milk fat concentration was decreased by 17.2%, 33.1% and 40.7% in response to CLA15, CLA30 and CLA45, respectively. Secretions of both de novo synthesized and preformed fatty acids were progressively reduced as the CLA dose increased, but the magnitude of the inhibition was greater for the former. There was a linear reduction in most milk fat desaturase indexes (14:1/14:0, 16:1/16:0, 17:1/17:0 and 18:1/18:0). Milk fat t10,c12-CLA concentration and secretion increased with the CLA dose, and its apparent transfer efficiency from diet to milk was 1.18%, 1.17% and 1.21% for CLA15, CLA30 and CLA45 treatments, respectively. The estimated energy balance was linearly improved in goats fed CLA.

Stearic acid does not overcome conjugated linoleic acid trans-10, cis-12-induced milk fat depression in lactating ewes

“…Importantly, our MDF induction model using a CLA rumenunprotected supplement was successful in reducing milk fat content and yield, as well as increasing trans-10, cis-12 CLA secretion in milk fat, while reducing the proportion of FA < 16C in the CLA and CLASA treatments. These results are in agreement with previous observations with lactating ewes (9,13) and goats (18,19) .…”

Energy balance in lactating goats: Response to mixture of conjugated linoleic acid

“…This is the why of the improvement in the energy balance when including CLA in the diet of lactating goats. These results are consistent with studies on goats (Baldin et al, ; Fernandes et al, ) and cows (von Soosten et al, ) supplemented with the same CLA isomer. The decrease in the energy value of goat milk due to the t 10, c 12 CLA isomer (Baldin et al, ) is linked with a decrease in non‐esterified fatty acids (NEFA) in the blood plasma, causing a lower mobilization of body reserves, and consequently an improvement in the energy balance (Adewuyi, Gruys, & Eerdenburg, ).…”

“…Supplementing lactating goats with ruminally protected c 9, t 11 CLA and t 10, c 12 CLA isomers in the diet had no significant effect on live weight or DM intake. Similar results were reported by Lock, Rovai, Gipson, Veth, and Bauman () and Ghazal et al () in studies with goats, as did Baldin et al () and Fernandes et al (), where the mentioned isomers had no ruminal protection. It is important to highlight that there was no effect on live weight or DM intake, even when the milk fat yield and concentration decreased from the effect of the t 10, c 12 CLA isomer, and consequently the NEL requirement decreased, which would lead us to expect an increase in live weight or a decrease in DM intake (Bauman et al, ).…”

“…Hence, the energy that is not used to synthesize milk fat would be expected to be used for other metabolic processes like increasing milk production and the concentration of protein or lactose in the milk or improving the energy balance of the animals (Harvatine, Perfield, & Bauman, 2009). However, according to Fernandes, Gama, Ribeiro, Lopes, andBaldin et al (2014), this is not true for lactating goats. In view of this, the question remains of where this energy is destined.…”

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.…”