The use of ensiled olive cake in the diets of Friesian cows increases beneficial fatty acids in milk and Halloumi cheese and alters the expression of SREBF1 in adipose tissue

Abstract

This study aimed to evaluate the effect of dietary inclusion of ensiled olive cake, a by-product of olive oil production, on milk yield and composition and on fatty acid (FA) profile of milk and Halloumi cheese from cows. Furthermore, the effect of olive cake on the expression of selected genes involved in mammary and adipose lipid metabolism was assessed in a subset of animals. A total of 24 dairy cows in mid lactation were allocated into 2 isonitrogenous and isoenergetic feeding treatments, named the control (CON) diet and the olive cake (OC) diet, in which part of the forages (alfalfa, barley hay, and barley straw) were replaced with ensiled OC as 10% of dry matter according to a 2 × 2 crossover design with two 28-d experimental periods. At the end of the second experimental period, mammary and perirenal adipose tissue samples were collected from 3 animals per group for gene expression analysis by quantitative reverse-transcription PCR. The expression of 11 genes, involved in FA synthesis (ACACA, FASN, G6PDH), FA uptake or translocation (VLDLR, LPL, SLC2A1, CD36, FABP3), FA saturation (SCD1), and transcriptional regulation (SREBF1, PPARG), was evaluated. No significant differences were observed between groups concerning milk yield, fat percentage, protein percentage, and protein yield (kg/d), whereas milk fat yield (kg/d) increased in the OC group. Dietary supplementation with ensiled OC modified the FA profile of milk and Halloumi cheese produced. There was a significant decrease in the concentration of de novo synthesized FA, saturated FA, and the atherogenic index, whereas long-chain and monounsaturated FA concentration was increased in both milk and cheese. Among individual saturated FA, only stearic acid was elevated, whereas among individual monounsaturated FA, increments of oleic acid (C18:1 cis-9) and the sum of C18:1 trans-10 and trans-11 acids were demonstrated in milk and Halloumi cheese produced. Although no diet effect was reported on total polyunsaturated FA, the concentration of CLA cis-9,trans-11 was increased in both milk and Halloumi cheese fat of the OC group. The expression of the genes tested was unaffected apart from an observed upregulation of SREBF1 mRNA expression in perirenal fat from cows fed the OC diet. Milk FA differences observed were not associated with alterations in mammary expression of genes involved in FA synthesis, uptake, translocation, and regulation of lipogenesis. Overall, the inclusion of ensiled OC in cow diets for a 4-wk period improved, beneficially for human health, the lipid profile of bovine milk and Halloumi cheese produced without adversely affecting milk yield and composition or the expression of genes involved in lipid metabolism of mammary and adipose tissues in cows.

Effect of Farming System (Organic vs. Conventional) and Season on Composition and Fatty Acid Profile of Bovine, Caprine and Ovine Milk and Retail Halloumi Cheese Produced in Cyprus

“…It has been reported that heating, the fermentation culture used, and the ripening time required for the production of cheese could potentially modulate cheese FA composition [ 4 ]. However, in our previous studies [ 28 , 54 ], the FA profiles of milk and related Halloumi cheese produced were similar, which suggested that the improvement in nutritional quality achieved in milk due to organic practices is possibly further maintained in organic Halloumi cheese in the present study.…”

“…The cheese fat was extracted with diethyl ether according to the method described by Neofytou et al [ 28 ]. Briefly, 50 mL of diethyl ether and 0.5 g of Na 2 SO 4 was added to 30 to 40 g of cheese samples and mixed vigorously.…”

Feeding olive cake silage up to 20% of DM intake in sheep improves lipid quality and health-related indices of milk and ovine halloumi cheese

“…Despite the low nutritive value of this by-product (Hadjipanayiotou 1999;Abbeddou et al 2015), its use may be promoted to the farmers and subsequently to the halloumi cheese manufacturers due to likely beneficial effects on fat quality. Our previous study using this ensiled OC by-product in cow diets at a rate of 10% DM showed improved lipid profile in both bovine milk and related halloumi cheese produced regarding total unsaturated lipids, atherogenicity indices, and particularly beneficial fatty acids (FA) such as conjugated linoleic acid (CLA 18:2 cis-9, trans-11, rumenic acid (RA)) and oleic acid content (Neofytou et al 2020). It is not known, however, if higher diet inclusion of OCS on diets may be used on sheep conferring any additional benefits on the quality of ovine milk and ovine halloumi cheese without detriments on milk production and/or intake.…”

“…Proposed processing methods such as drying and partly destoned and dried (Abbeddou et al 2011a(Abbeddou et al , b, 2015, inclusion into multi-nutrient blocks (Molina-Alcaide et al 2010), or pelleted with other ingredients (Castellani et al 2017) add extra cost, time, and labor and therefore possibly outweigh its usefulness as an affordable forage substitution alternative. However, a cost-effective method of OC preservation is suggested by researchers in Cyprus (Hadjipanayiotou 1999;Symeou et al 2019;Neofytou et al 2020) through silage preparation using fresh OC, shortly after production, without any costs of processing or additives (olive cake silage, OCS), allowing extended storage time and consequently use throughout the year as a forage alternative.…”

NETosis of Peripheral Neutrophils Isolated From Dairy Cows Fed Olive Pomace

“…These results were confirmed by the positive correlation found between NE-DNA complexes produced during NETosis and intracellular H 2 O 2 controlled by MPO activity, and were probably due to the major content of OA in the OP diet found in the present study. Neofytou et al ( 72 ), supplementing cows with 10% of ensiled olive cake, with a level of OA of about 30% of the dietary lipids, observed a reduction of medium-chain FA concentration and increased long-chain FA (LCFA) levels in cow's milk ( 72 ). The direct transfer between blood to milk constituent ( 73 ) could suggest that OA from the diet could have represented a suitable energy source to initiate an effective neutrophil response.…”