Effects of supplementation of green tea extract on the milk performance of peripartal dairy cows and the expression of stress response genes in the liver

Abstract

Background: We hypothesised that supplementation of green tea extract (GTE) in dairy cows during the transition period can attenuate proinflammatory conditions and prevent endoplasmic reticulum (ER) stress in the liver of these cows. Thirty Holstein cows with an average parity of 3.06 (± 1.31, SD) were divided into a control group and a group that received a daily amount of 10 g of GTE from d 7 before the calving day and a daily amount of 20 g of GTE from the day of calving until d 7 of lactation. Results: Cows supplemented with GTE did not show differences in energy intake or milk yield in weeks 2-7 of lactation. However, these cows had a lower milk fat concentration and a lower energy corrected milk yield than the control cows and showed a trend of improved energy balance. The relative mRNA concentrations of proinflammatory genes, genes involved in the acute phase reaction and antioxidant genes in the liver in weeks 1, 4 and 7 of lactation were not different between the two groups of cows. The concentrations of α-tocopherol and the Trolox equivalent antioxidant capacity in plasma were not different between the two groups. However, the group supplemented with GTE showed significant reductions of some genes of the unfolded protein response (UPR) in week 1 and a trend of lower liver triacylglycerol (TAG) concentrations in the liver compared to the control group. Conclusions: This study shows that supplementation of GTE in dairy cows lowers the fat concentration in the milk but overall has no effect on the expression of inflammatory genes and the antioxidative status in dairy cows during early lactation. The finding of reduced mRNA levels of genes involved in the UPR at week 1, however, supports other results showing that supplementation of polyphenols could prevent the development of ER stress in the liver of cows during early lactation. The finding of a tendency towards a reduced TAG concentration in the liver of cows supplemented with GTE might be due to an improved energy balance in these cows.

Maternal Supplementation with a Cocoa Extract during Lactation Deeply Modulates Dams’ Metabolism, Increases Adiponectin Circulating Levels and Improves the Inflammatory Profile in Obese Rat Offspring

“…The lower content of lipids detected in the mammary gland of our lactating dams supplemented with CCX probably reflects a lower concentration of milk lipids, since this has been consistently described in the literature [ 44 , 45 ]. Other polyphenolic extracts, such as a green tea extract, have been shown to decrease milk fat concentration in dairy cows [ 46 ]. In fact, our group has previously published similar results induced by the intake of GSPE in lactating rats [ 25 ].…”

Effects of PUFA-Rich Dietary Strategies on Ruminants’ Mammary Gland Gene Network: A Nutrigenomics Review

“…Moreover, resveratrol (50 µM) induced similar effects in bovine MECs challenged with H 2 O 2 [ 89 ]. However, it is worth mentioning that the use of polyphenols extracted from green tea in vivo had no effect on oxidative stress in peripartal cows [ 107 ]. Considering the in vivo trials, it has been reported that the post-ruminal bioavailability of tea-polyphenols may play a critical role in their antioxidant impact [ 108 ].…”

Performance and Metabolic, Inflammatory, and Oxidative Stress-Related Parameters in Early Lactating Dairy Cows with High and Low Hepatic FGF21 Expression

“…The experimental protocol was approved by the official authorities (Provincial Government of Coblenz, Germany, approval number 23 177-07/G15-20-040). The cows were fed a total mixed ration (TMR), as recently described [30]. The TMR offered during the dry period was composed to meet the requirement of crude protein (CP) and net energy of a cow with a body weight of 650 kg and daily dry matter intake of 12 kg.…”

“…Blood and liver biopsy samples were taken 2 weeks (12-16 days) before the expected calving date, and at week 1 (days 6-12), week 4 (days [25][26][27][28][29][30][31][32], and week 7 (days 46-52) postpartum. Blood sampling was performed from V. caudalis mediana into EDTA-containing vacutainers (S-Monovette 9 mL, Sarstedt, Nümbrecht, Germany) and kept on ice following centrifugation to obtain plasma samples, which were then stored at −80 • C pending analysis.…”

“…For this investigation, total RNA was obtained from liver samples taken at week 1 postpartum from 30 cows. Total RNA was extracted as recently described [30]. Processing of total RNA samples was carried out at an Affymetrix service provider, as previously described [22].…”