Mammary gene expression and activity of antioxidant enzymes and concentration of the mammalian lignan enterolactone in milk and plasma of dairy cows fed flax lignans and infused with flax oil in the abomasum

The promising antioxidant effects of lignans: Nrf2 activation comes into view

Lignans are biologically active compounds widely distributed, recognized, and identified in seeds, fruits, and vegetables. Lignans have several intriguing bioactivities, including anti-inflammatory, antioxidant, and anticancer activities. Nrf2 controls the expression of many cytoprotective genes. Activation of Nrf2 is a promising therapeutic approach for treating and preventing diseases resulting from oxidative injury and inflammation. Lignans have been demonstrated to stimulate Nrf2 signaling in a variety of in vitro and experimental animal models. The review summarizes the findings of fourteen lignans (Schisandrin A, Schisandrin B, Schisandrian C, Magnolol, Honokiol, Sesamin, Sesamol, Sauchinone, Pinoresinol, Phyllanthin, Nectandrin B, Isoeucommin A, Arctigenin, Lariciresinol) as antioxidative and anti-inflammatory agents, affirming how Nrf2 activation affects their pharmacological effects. Therefore, lignans may offer therapeutic candidates for the treatment and prevention of various diseases and may contribute to the development of effective Nrf2 modulators.

Natural polyphenols for drug delivery and tissue engineering construction: A review

Polyphenols, natural compounds rich in phenolic structures, are gaining prominence due to their antioxidant, anti-inflammatory, antibacterial, and anticancer properties, making them valuable in biomedical applications. Through covalent and noncovalent interactions, polyphenols can bind to biomaterials, enhancing their performance and compensating for their shortcomings. Such polyphenol-based biomaterials not only increase the efficacy of polyphenols but also improve drug stability, control release kinetics, and boost the therapeutic effects of drugs. They offer the potential for targeted drug delivery, reducing off-target impacts and enhancing therapeutic outcomes. In tissue engineering, polyphenols promote cell adhesion, proliferation, and differentiation, thus aiding in the formation of functional tissues. Additionally, they offer excellent biocompatibility and mechanical strength, essential in designing scaffolds. This review explores the significant roles of polyphenols in tissue engineering and drug delivery, emphasizing their potential in advancing biomedical research and healthcare.

Effects of antioxidant-rich Lactiplantibacillus plantarum inoculated alfalfa silage on rumen fermentation, antioxidant and immunity status, and mammary gland gene expression in dairy goats

BACKGROUND

Milk synthesis in lactating animals demands high energy metabolism, which results in an increased production of reactive oxygen metabolites (ROM) causing an imbalance between oxidants and antioxidants thereby inducing oxidative stress (OS) on the animals. To mitigate OS and postpartum disorders in dairy goats and gain insight into the impact of dietary choices on redox status during lactation, a feeding trial was conducted using alfalfa silage inoculated with a high-antioxidant strain of Lactiplantibacillus plantarum.

METHODS

Twenty-four Guanzhong dairy goats (38.1 ± 1.20 kg) were randomly assigned to two dietary treatments: one containing silage inoculated with L. plantarum MTD/1 (RSMTD-1), and the other containing silage inoculated with high antioxidant activity L. plantarum 24-7 (ES24-7).

RESULTS

ES24-7-inoculated silage exhibited better fermentation quality and antioxidant activity compared to RSMTD-1. The ES24-7 diet elevated the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities in milk, serum, and feces of lactating goats (with the exception of T-AOC in milk). Additionally, the diet containing ES24-7 inoculated silage enhanced casein yield, milk free fatty acid (FFA) content, and vitamin A level in the goats' milk. Furthermore, an increase of immunoglobulin (Ig)A, IgG, IgM, interleukin (IL)-4, and IL-10 concentrations were observed, coupled with a reduction in IL-1β, IL-2, IL-6, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α concentrations in the serum of lactating goats fed ES24-7. Higher concentrations of total volatile fatty acid (VFA), acetate, and propionate were observed in the rumen fluid of dairy goats fed ES24-7 inoculated silage. Moreover, the diet containing ES24-7 inoculated silage significantly upregulated the expression of nuclear factor erythroid 2 like 2 (NFE2L2), beta-carotene oxygenase 1 (BCO1), SOD1, SOD2, SOD3, GPX2, CAT, glutathione-disulfide reductase (GSR), and heme oxygenase 1 (HMOX1) genes in the mammary gland, while decreased the levels of NADPH oxidase 4 (NOX4), TNF, and interferon gamma (IFNG).

CONCLUSIONS

These findings indicated that feeding L. plantarum 24-7 inoculated alfalfa silage not only improved rumen fermentation and milk quality in lactating dairy goats but also boosted their immunity and antioxidant status by modulating the expression of several genes related to antioxidant and inflammation in the mammary gland.

Abomasal infusion of essential fatty acids and conjugated linoleic acid during late pregnancy and early lactation affects immunohematological and oxidative stress markers in dairy cows

Oxidative stress and inflammation, as natural parts of metabolic adaptations during the transition from late gestation to early lactation, are critical indicators of dairy cows' metabolic health. This study was designed to investigate the effects of abomasal infusion of essential fatty acids (EFA), particularly α-linolenic acid, and conjugated linoleic acid (CLA) on plasma, erythrocyte, and liver markers of oxidative stress in dairy cows during the transition period. Rumen-cannulated German Holstein cows (n = 38) in their second lactation (11,101 ± 1,118 kg milk/305 d, mean ± standard deviation) were abomasally infused with one of the following treatments from d -63 antepartum until d 63 postpartum (PP): CTRL (n = 9; 76 g/d coconut oil); EFA (n = 9; 78 g/d linseed plus 4 g/d safflower oil); CLA (n = 10; isomers cis-9,trans-11 and trans-10,cis-12 CLA; 38 g/d); and EFA+CLA (n = 10; 120 g/d). Hematological parameters as well as markers of oxidative status were measured in plasma, erythrocytes, and liver before and after calving. Immunohematological parameters, including erythrocyte number, hematocrit, hemoglobin, mean corpuscular hemoglobin, leukocytes, and basophils, were affected by time, and their peak levels were observed on the day after calving. The oxidative stress markers glutathione peroxidase 1 and reactive oxygen metabolites in plasma and erythrocytes were both affected by time, exhibiting the highest levels on d 1 PP, whereas β-carotene, retinol, and tocopherol were at their lowest levels at the same time. Immunohematological parameters were only marginally affected by fatty acid treatment in a time-dependent manner. As such, lymphocyte and atypical lymphocyte counts were both significantly highest in the groups that received EFA at d 1 PP. Moreover, EFA supplementation increased the mean corpuscular volume and showed a trend for induction of mean corpuscular hemoglobin compared with the CLA group during the transition period. The PP mean thrombocyte volume was higher in the EFA than in the CLA group (except for d 28) and both EFA and CLA reduced number of thrombocytes and thrombocrit at distinct time points. Hepatic mRNA abundance of markers related to oxidative status, including glutathione peroxidase (GPX-1) and catalase (CAT), was lower (P < 0.05) in EFA-treated than non-EFA-treated cows at d 28 PP. Dairy cows at the onset of lactation were characterized by induced markers of both oxidative stress and inflammation. Supplementing EFA and CLA had minor and time-dependent effects on markers of oxidative stress in plasma, erythrocytes, and liver. A comparison of EFA supplementation with CLA or CTRL showed higher immunohematological response at d 1 PP and lower hepatic antioxidant levels by d 28 PP. Supplementation with EFA+CLA had only a minor effect on oxidative markers, which were more similar to those with the EFA treatment. Altogether, despite the time-dependent differences, the current findings show only minor effects of EFA and CLA supplementation in the prevention of early lactation-induced oxidative stress.

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

Although the inclusion of polyunsaturated fatty acids (PUFAs) in ruminants' diets appears to be a well-documented strategy to enrich milk with PUFAs, several gene networks that regulate milk synthesis and mammary gland homeostasis could be impaired. The objective of this literature review is to assess the effects of nutritional strategies focused on enriching milk with PUFAs on gene networks regulating mammary gland function and lipogenesis, as well as the impact of feed additives and bioactive compounds with prominent antioxidant potential on immune-oxidative transcriptional profiling, as a part of mammary gland homeostasis and health. The findings support the conclusion that PUFAs' inclusion in ruminants' diets more strongly downregulate the stearoyl-CoA desaturase (SCD) gene compared to other key genes involved in de novo fatty acid synthesis in the mammary gland. Additionally, it was revealed that seed oils rich in linoleic and linolenic acids have no such strong impact on networks that regulate lipogenic homeostasis compared to marine oils rich in eicosapentaenoic and docosahexaenoic acids. Furthermore, ample evidence supports that cows and sheep are more prone to the suppression of lipogenesis pathways compared to goats under the impact of dietary marine PUFAs. On the other hand, the inclusion of feed additives and bioactive compounds with prominent antioxidant potential in ruminants' diets can strengthen mammary gland immune-oxidative status. Considering that PUFA's high propensity to oxidation can induce a cascade of pro-oxidant incidences, the simultaneous supplementation of antioxidant compounds and especially polyphenols may alleviate any side effects caused by PUFA overload in the mammary gland. In conclusion, future studies should deeply investigate the effects of PUFAs on mammary gland gene networks in an effort to holistically understand their impact on both milk fat depression syndrome and homeostatic disturbance.

The Effect of Anthocyanins from Dioscorea alata L. on Antioxidant Properties of Perinatal Hainan Black Goats and Its Possible Mechanism in the Mammary Gland

(1) Background: The mammary glands of the perinatal goats are susceptible to reactive oxygen species (ROS) leading to oxidative injury. Although Dioscorea alata L. is rich in anthocyanins with high safety and excellent free-radical-scavenging ability, the effect and mechanism of Dioscorea alata L. anthocyanins (DAC) on the antioxidant capacity of the black Hainan goat has been the subject of few studies to date; (2) Methods: For this reason, feeding experiments were performed by feeding experimental diets, and the pre-protective capacity of DAC on goat mammary epithelial cells was explored on the basis of the established model of H₂O₂ injury; (3) Results: As well as altering rumen fermentation parameters in perinatal female goats, dietary challenge also improves antioxidant capacity in their blood and milk. thereby enhancing children's antioxidant capacity and increasing their resistance to oxidative stress. However, we also found that DAC pretreatment was capable of activating both Nrf2 and MAPK/JNK pathways, which results in enhanced antioxidase activity and elimination of ROS; (4) Conclusions: Together, these findings suggest that DAC may have a pre-protective role on perinatal Hainan black goats through the regulation of Nrf2 and MAPK/JNK pathways in GMEC.

Effects of Intramuscular Injections of Vitamins AD3E and C in Combination on Fertility, Immunity, and Proteomic and Transcriptomic Analyses of Dairy Cows during Early Gestation

This research aimed to investigate the effects of the intramuscular injection of vitamins AD3E and C in combination immediately before the estrus synchronization program (the Ovsynch program) on conception and pregnancy rates, blood parameters, serum biochemical properties, immune systems, antioxidant parameters, and proteomic and transcriptomic analyses during early gestation in dairy cows. Forty nonlactating multiparous cows were randomly assigned to one of four treatments: (1) C: control with normal saline injection; (2) VAD3E: a single intramuscular injection (I/M) of vitamin AD3E; (3) VAD3EC: injection of both vitamins AD3E and C; (4) VC: a single dose of vitamin C. Blood and serum samples were taken immediately at day 0 (before AI), day 7, and day 14 (after AI for 5 days) from the coccygeal vein. Generally, injections of AD3E and C in combination had no effect on the rate of conception or pregnancy. However, they improved hematological parameters and immune and antioxidant activities. Serum samples were analyzed using LC-MS/MS, and 8190 proteins were identified. Five proteins were successfully validated using the quantitative real-time reverse transcription PCR (qRT-PCR) method. This study found that lymphocyte-specific protein 1 (LSP1, A0A3Q1M894) could be used as a protein biomarker for cows administrated with vitamins AD3E and C.

Dietary lignans, plasma enterolactone levels, and metabolic risk in men: exploring the role of the gut microbiome

BACKGROUND

The conversion of plant lignans to bioactive enterolignans in the gastrointestinal tract is mediated through microbial processing. The goal of this study was to examine the relationships between lignan intake, plasma enterolactone concentrations, gut microbiome composition, and metabolic risk in free-living male adults.

RESULTS

In 303 men participating in the Men's Lifestyle Validation Study (MLVS), lignan intake was assessed using two sets of 7-day diet records, and gut microbiome was profiled through shotgun sequencing of up to 2 pairs of fecal samples (n = 911). A score was calculated to summarize the abundance of bacteria species that were significantly associated with plasma enterolactone levels. Of the 138 filtered species, plasma enterolactone levels were significantly associated with the relative abundances of 18 species at FDR < 0.05 level. Per SD increment of lignan intake was associated with 20.7 nM (SEM: 2.3 nM) higher enterolactone concentrations among participants with a higher species score, whereas the corresponding estimate was 4.0 nM (SEM: 1.7 nM) among participants with a lower species score (P for interaction < 0.001). A total of 12 plasma metabolites were also significantly associated with these enterolactone-predicting species. Of the association between lignan intake and metabolic risk, 19.8% (95%CI: 7.3%-43.6%) was explained by the species score alone, 54.5% (95%CI: 21.8%-83.7%) by both species score and enterolactone levels, and 79.8% (95%CI: 17.7%-98.6%) by further considering the 12 plasma metabolites.

CONCLUSION

We identified multiple gut bacteria species that were enriched or depleted at higher plasma levels of enterolactone in men. These species jointly modified the associations of lignan intake with plasma enterolactone levels and explained the majority of association between lignan intake and metabolic risk along with enterolactone levels and certain plasma metabolites.

Gut microbiota-derived metabolites and risk of coronary artery disease: a prospective study among US men and women

BACKGROUND

Accumulating evidence has suggested that human gut microbiota metabolize certain dietary compounds and subsequently produce bioactive metabolites that may exert beneficial or harmful effects on coronary artery disease (CAD) risk.

OBJECTIVES

This study examined the joint association of 2 gut microbiota metabolites, enterolactone and trimethylamine N-oxide (TMAO), that originate from intake of plant-based foods and animal products, respectively, in relation to CAD risk.

METHODS

A prospective nested case-control study of CAD was conducted among participants who were free of diabetes, cardiovascular disease, and cancer in the Nurses' Health Study II and the Health Professionals Follow-up Study. Plasma concentrations of enterolactone and TMAO, as well as choline and L-carnitine, were assayed among 608 CAD case-control pairs.

RESULTS

A high enterolactone and low TMAO profile was associated with better diet quality, especially higher intake of whole grains and fiber and lower intake of red meats, as well as lower concentrations of plasma triglycerides and C-reactive protein. Participants with a high enterolactone/low TMAO profile had a significantly lower risk of CAD: the multivariate-adjusted OR was 0.58 (95% CI: 0.38, 0.90), compared with participants with a low enterolactone/high TMAO profile. No significant interaction between enterolactone and TMAO on CAD risk was observed. Neither TMAO nor enterolactone alone were associated with CAD risk in pooled analyses. In women, a higher enterolactone concentration was significantly associated with a 54% lower CAD risk (P trend = 0.03), although the interaction by sex was not significant.

CONCLUSIONS

Our results show that a profile characterized by high enterolactone and low TMAO concentrations in plasma is linked to a healthful dietary pattern and significantly associated with a lower risk of CAD. Overall, these data suggest that, compared with individual markers, multiple microbiota-derived metabolites may facilitate better differentiation of CAD risk and characterization of the relations between diet, microbiota, and CAD risk.

Flaxseed Lignans as Important Dietary Polyphenols for Cancer Prevention and Treatment: Chemistry, Pharmacokinetics, and Molecular Targets

Cancer causes considerable morbidity and mortality across the world. Socioeconomic, environmental, and lifestyle factors contribute to the increasing cancer prevalence, bespeaking a need for effective prevention and treatment strategies. Phytochemicals like plant polyphenols are generally considered to have anticancer, anti-inflammatory, antiviral, antimicrobial, and immunomodulatory effects, which explain their promotion for human health. The past several decades have contributed to a growing evidence base in the literature that demonstrate ability of polyphenols to modulate multiple targets of carcinogenesis linking models of cancer characteristics (i.e., hallmarks and nutraceutical-based targeting of cancer) via direct or indirect interaction or modulation of cellular and molecular targets. This evidence is particularly relevant for the lignans, an ubiquitous, important class of dietary polyphenols present in high levels in food sources such as flaxseed. Literature evidence on lignans suggests potential benefit in cancer prevention and treatment. This review summarizes the relevant chemical and pharmacokinetic properties of dietary polyphenols and specifically focuses on the biological targets of flaxseed lignans. The consolidation of the considerable body of data on the diverse targets of the lignans will aid continued research into their potential for use in combination with other cancer chemotherapies, utilizing flaxseed lignan-enriched natural products.

Muscle Antioxidant Enzymes Activity and Gene Expression Are Altered by Diet-Induced Increase in Muscle Essential Fatty Acid (α-linolenic acid) Concentration in Sheep Used as a Model

This study investigated the effect of dietary manipulations on muscle fatty acid composition, the activities and relative mRNA expressions of antioxidant enzymes and the relationship between muscle enzyme activity or mRNA expression and alpha linolenic acid (ALA) concentration in sheep. Eighty-four lambs blocked on liveweight were randomly allocated to four dietary treatments, lucerne pasture (Lucerne), annual ryegrass pasture (Ryegrass), feedlot pellets (Feedlot) or annual ryegrass plus feedlot pellets (RyeFeedlot). After six weeks of feeding, lambs were slaughtered and within 30 min post-mortem, samples collected from the longissimus lumborum (LL) muscle for RNA isolation and measurement of antioxidant enzyme activities. At 24 h post-mortem, LL samples were collected for determination of fatty acid concentrations. Feedlot treatment decreased ALA, eicosapentaenoic (EPA), docosapentaenoic (DPA) and docosahexaenoic (DHA) concentrations compared with other treatments and increased linoleic acid (LA) and arachidonic acid (AA) compared with Lucerne and Ryegrass (p < 0.001). The activity of Glutathione peroxidase (GPX1, p < 0.001) and Superoxide dismutase (SOD2, p < 0.001) enzymes in the muscle increased with Lucerne compared to other treatments. Lucerne increased muscle gpx1 mRNA expression by 1.74-fold (p = 0.01) and 1.68-fold (p = 0.05) compared with Feedlot and other diets, respectively. The GPX1 (r² = 0.319, p = 0.002) and SOD2 (r² = 0.244, p = 0.009) enzyme activities were positively related to ALA. There was a positive linear relationship between muscle gpx1 (r² = 0.102, p = 0.017) or sod2 (r² = 0.049, p = 0.09) mRNA expressions and ALA concentration. This study demonstrates that diet can affect concentrations of ALA and other fatty acids as well as change activities and gene expression of antioxidant enzymes in muscle. Increased antioxidant activity may, in turn, have beneficial effects on the performance, health and wellbeing of animals and humans.

Effects of anthocyanin-rich purple corn (Zea mays L.) stover silage on nutrient utilization, rumen fermentation, plasma antioxidant capacity, and mammary gland gene expression in dairy goats1

Eight healthy multiparous Saanen dairy goats (41.50 ± 1.84 kg) were assigned to a double 4 × 4 Latin square design. The four treatment diets were: (i) negative control, rice straw (NC); (ii) first positive control, sticky corn stover silage (PC1); (iii) second positive control, PC1 with 1 g/d commercial purple corn pigment (PC2); and (iv) anthocyanin-rich purple corn stover silage (PSS; AR). DMI did not differ (P > 0.05) among the treatments. Goats receiving the NC tended (P < 0.05) to reduce nutrient apparent digestibility, nitrogen (N) absorption, N retention, and volatile fatty acid production relative to the other groups. The levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and superoxide dismutase (SOD) in plasma were greater (P < 0.05) in goats fed PC2 and AR compared with NC and PC1. The inclusion of PC2 and AR increased (P < 0.05) the abundance of nuclear factor (erythroid-derived 2)-like 2 (NFE2L2), but decreased (P < 0.05) the level of tumor necrosis factor in the mammary gland. Moreover, goats receiving AR tended to increase (P < 0.05) the levels of SOD2, GPX1, and GPX2 mRNA expression in the mammary gland. There were significant (P < 0.05) positive correlations between DPPH scavenging activity, total antioxidant capacity, SOD, catalase enzymes in plasma, and the abundance of NFE2L2 in the mammary gland. In addition, stronger (P < 0.05) positive correlations were noted between the expression of several inflammation related and antioxidant genes. Collectively, the results from the current study indicated that the consumption of anthocyanin-rich PSS by dairy goats had the potential to enhance antioxidant potential by improving antioxidant capacity in plasma and by modulating the abundance of several inflammation related and antioxidant genes in the mammary gland.

A Review of Lignan Metabolism, Milk Enterolactone Concentration, and Antioxidant Status of Dairy Cows Fed Flaxseed

Lignans are polyphenolic compounds with a wide spectrum of biological functions including antioxidant, anti-inflammatory, and anticarcinogenic activities, therefore, there is an increasing interest in promoting the inclusion of lignan-rich foods in humans' diets. Flaxseed is the richest source of the lignan secoisolariciresinol diglucoside-a compound found in the outer fibrous-containing layers of flax. The rumen appears to be the major site for the conversion of secoisolariciresinol diglucoside to the enterolignans enterodiol and enterolactone, but only enterolactone has been detected in milk of dairy cows fed flaxseed products (whole seeds, hulls, meal). However, there is limited information regarding the ruminal microbiota species involved in the metabolism of secoisolariciresinol diglucoside. Likewise, little is known about how dietary manipulation such as varying the nonstructural carbohydrate profile of rations affects milk enterolactone in dairy cows. Our review covers the gastrointestinal tract metabolism of lignans in humans and animals and presents an in-depth assessment of research that have investigated the impacts of flaxseed products on milk enterolactone concentration and animal health. It also addresses the pharmacokinetics of enterolactone consumed through milk, which may have implications to ruminants and humans' health.

Dietary magnesium deficiency impaired intestinal structural integrity in grass carp (Ctenopharyngodon idella)

Grass carp (223.85–757.33 g) were fed diets supplemented with magnesium (73.54–1054.53 mg/kg) for 60 days to explore the impacts of magnesium deficiency on the growth and intestinal structural integrity of the fish. The results demonstrated that magnesium deficiency suppressed the growth and damaged the intestinal structural integrity of the fish. We first demonstrated that magnesium is partly involved in (1) attenuating antioxidant ability by suppressing Nrf2 signalling to decrease antioxidant enzyme mRNA levels and activities (except CuZnSOD mRNA levels and activities); (2) aggravating apoptosis by activating JNK (not p38MAPK) signalling to upregulate proapoptotic protein (Apaf-1, Bax and FasL) and caspase-2, -3, -7, -8 and -9 gene expression but downregulate antiapoptotic protein (Bcl-2, IAP and Mcl-1b) gene expression; (3) weakening the function of tight junctional complexes (TJs) by promoting myosin light chain kinase (MLCK) signalling to downregulate TJ gene expression [except claudin-7, ZO-2b and claudin-15 gene expression]. Additionally, based on percent weight gain (PWG), against reactive oxygen species (ROS), against caspase-9 and claudin-3c in grass carp, the optimal dietary magnesium levels were calculated to be 770.38, 839.86, 856.79 and 811.49 mg/kg, respectively.

Interleukin-7 improves in vitro maturation of ovine cumulus-oocyte complexes in a dose dependent manner

Interleukin-7 (IL-7) mediated signals are linked to development, proliferation, survival and differentiation of cells. Recent evidences indicate its role in oocyte maturation process as well. Nevertheless, the underlying mechanisms of IL-7 involvement in oocyte maturation are not well characterized. In addition, currently no information is available on the effect of exogenous IL-7 on oocyte maturation in ovine or any other species. In this study, the effect of IL-7 supplementation during in vitro maturation (IVM) on the maturation rate, production of reactive oxygen species (ROS) and gene expression of ovine cumulus-oocyte complexes (COC) was assessed. IL-7 (0.5, 1, 2, 5 and 10 ng/ml) was supplemented in IVM medium at the beginning (0 h) and maturation rate of COC was assessed at the completion of IVM (24 h). The maturation rate (%) was found significantly (P = 0.000) greater with the 1 ng/ml of IL-7 supplementation (69.5) than control (60.0). In contrast, the maturation rate was reduced significantly (P = 0.000) with the 2 (47.1), 5 (39.2) and 10 ng/ml (39.1) of IL-7 as compared to the control. The level of intracellular ROS in the matured COC was found considerably higher with the 5 ng/ml of IL-7 followed by 1 ng/ml of IL-7 and control. It was evident that in the presence of superoxide dismutase-inhibitor, 1 ng/ml of IL-7 did not stimulate oocyte maturation. In contrast, oocyte maturation was improved with 5 ng/ml of IL-7 supplementation in the presence of NADPH-oxidase-inhibitor. IL-7 supplementation influenced gene expression in COC in a dose and time dependant manner. The expression of genes related to ROS production and apoptosis were upregulated and the genes associated with antioxidant mechanisms were downregulated noticeably with the supplementation of 5 ng/ml of IL-7. In conclusion, IL-7 at low concentration was beneficial for oocyte maturation, which was likely mediated through the favourable level of intracellular ROS and antioxidant mechanisms. In contrast, the detrimental effects of greater IL-7 concentrations on oocyte maturation were possibly arbitrated through the ROS-mediated oxidative stress, compromised antioxidant mechanism and stimulated apoptotic signalling.

Flaxseed-enriched diets change milk concentration of the antimicrobial danofloxacin in sheep

BACKGROUND

Flaxseed is the most common and rich dietary source of lignans and is an acceptable supply of energy for livestock. Flaxseed lignans are precursors of enterolignans, mainly enterolactone and enterodiol, produced by the rumen and intestinal microbiota of mammals and have many important biological properties as phytoestrogens. Potential food-drug interactions involving flaxseed may be relevant for veterinary therapy, and for the quality and safety of milk and dairy products. Our aim was to investigate a potential food-drug interaction involving flaxseed, to explore whether the inclusion of flaxseed in sheep diet affects concentration of the antimicrobial danofloxacin in milk.

RESULTS

Increased concentrations of enterodiol and enterolactone were observed in sheep plasma and milk after 2 weeks of flaxseed supplementation (P < 0.05). However, enterolactone and enterodiol conjugates were not detected in milk. Milk danofloxacin pharmacokinetics showed that area under the curve (AUC)0-24, maximum concentration (Cmax) and AUC0-24 milk-to-plasma ratios were reduced by 25-30% in sheep fed flaxseed-enriched diets (P < 0.05). Our results demonstrate, therefore, that flaxseed-enriched diets reduce the amount of danofloxacin in sheep milk and enrich the milk content of lignan-derivatives.

CONCLUSION

These findings highlight an effect of flaxseed-enriched diets on the concentration of antimicrobials in ruminant's milk, revealing the potential of these modified diets for the control of residues of antimicrobial drugs in milk.

Linoleic acid, α-linolenic acid and enterolactone affect lipid oxidation and expression of lipid metabolism and antioxidant-related genes in hepatic tissue of dairy cows

Although beneficial effects have been attributed to PUFA supplementation in high-yielding dairy cows, diets rich in PUFA may also increase oxidative stress in tissues such as the liver. To fully exploit the health benefits of PUFA, we believe that the addition of natural antioxidants could help in preventing oxidative damage. Using an in vitro precision-cut liver slices (PCLS) tissue culture system, we investigated the effects of different linoleic acid (LA, n-6):α-linolenic acid (ALA, n-3) ratios (LA:ALA ratio of 4, LA:ALA ratio of 15 and LA:ALA ratio of 25) in the presence or absence of the antioxidant enterolactone (ENL) on (1) the mRNA abundance of genes with key roles in hepatic lipid metabolism, oxidative stress response and inflammatory processes, (2) oxidative damages to lipids and proteins and (3) superoxide dismutase activity in early-lactating dairy cows. The addition of LA and ALA to PCLS culture media increased oxidative damage to lipids as suggested by higher concentrations of thiobarbituric acid reactive substances and increased the expression of nuclear factor erythroid 2-related factor 2 target genes. The addition of ENL was effective in preventing lipid peroxidation caused by LA and ALA. Transcript abundance of sterol regulatory element-binding transcription factor 1 and its lipogenic target genes acetyl-CoA carboxylase α, fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD) was decreased with LA and ALA, whereas ENL decreased FASN and SCD gene expression. Our results show that addition of LA and ALA to PCLS culture media lowers hepatic lipogenic gene expression and increases oxidative damages to lipids. On the other hand, addition of ENL prevents oxidative damages provoked by these PUFA.

Lipopolysaccharide derived from the digestive tract provokes oxidative stress in the liver of dairy cows fed a high-grain diet

The aims of this study were to measure oxidative stress parameters and to investigate the molecular mechanism triggered by grain-induced subacute ruminal acidosis in mid-lactation cows. Twelve Holstein-Friesian cows with an average weight of 455±28kg were divided into 2 groups and subjected to 2 diets over 18wk: either a low-grain (forage-to-concentrate ratio=6:4) or a high-grain (forage-to-concentrate ratio=4:6) diet based on dry matter. Being fed a long-term high-grain diet resulted in a significant decrease in rumen pH and a significant increase in ruminal lipopolysaccharide (LPS) at 4 h postfeeding in the morning. The increase was also observed in LPS concentrations in the portal vein, hepatic vein, and jugular vein blood plasma as well as reduced milk yield in a high-grain diet. Cows fed a high-grain diet had lower levels of catalase and glutathione peroxidase (GPx) activity and total antioxidant capacity than cows fed a low-grain diet; however, super oxide dismutase (SOD) activity and malondialdehyde (MDA) levels were higher in both the liver and the plasma of high-grain than in low-grain cows. Positive correlations were observed between plasma LPS versus hepatic MDA, plasma MDA, and hepatic SOD activity, whereas hepatic GPx and plasma GPx were negatively correlated with plasma LPS. The relative mRNA abundances of GPX1 and CAT were significantly lower in the liver of cows fed a high-grain diet than those fed a low-grain diet, whereas SOD1 was significantly higher in cows fed a high-grain diet than cows fed a low-grain diet. The expression levels of Nrf2, NQO1, MT1E, UGT1A1, MGST3, and MT1A were downregulated, whereas NF-kB was upregulated, in cows fed a high-grain diet. Furthermore, nuclear factor E2-related factor 2 (Nrf2) total protein and mRNA levels were significantly lower than in low-grains. Our results demonstrate the relationship between the translocated LPS and the suppression of cellular antioxidant defense capacity, which lead to increased oxidative stress and suggests that the Nrf2-dependent antioxidant response may be affected by higher levels of LPS translocated to the bloodstream.

Milk yield, milk composition, and hepatic lipid metabolism in transition dairy cows fed flaxseed or linola

The response of transition dairy cows to dietary supplementation with fat sources of various fatty acid profiles could affect hepatic fat metabolism differently. Twenty-eight Holstein cows were blocked for similar calving date 4wk before expected parturition to compare the effects of feeding sources of n-3 and n-6 fatty acids on milk production and composition, plasma metabolites, and liver parameters. Cows within each block were assigned to 1 of 3 isonitrogenous and isoenergetic diets: control with a source of calcium salts of palm oil (MEG; 1.1 and 2.6% of the dry matter in prepartum and postpartum diets, respectively); n-3 fatty acids supplied as whole flaxseed (WFL; 4.8 and 7.7% of the dry matter in prepartum and postpartum diets, respectively); and n-6 fatty acids supplied as whole linola (WLO; 4.8 and 7.7% of the dry matter in prepartum and postpartum diets, respectively). Diets were fed until wk 14 of lactation. Contrasts of WFL versus WLO and polyunsaturated fatty acids versus MEG were compared. Cows fed polyunsaturated fatty acids increased dry matter intake over time at a greater extent than those fed MEG, which resulted in enhanced energy balance. Cows fed MEG produced more milk compared with those fed polyunsaturated fatty acids, and there was no difference between those fed WFL and WLO. We found no effect on body condition score and body weight. Plasma concentrations of glucose, fatty acids, and BHB were similar among diets. There was no effect of diet on concentration of glycogen and activities of superoxide dismutase and glutathione peroxidase in the liver. We observed higher concentrations of hepatic lipids and triacylglycerol in cows fed MEG compared with those fed polyunsaturated fatty acids, and no difference between WFL and WLO. Hepatic catalase activity tended to be higher on wk 4 after calving for cows supplemented with WFL compared with those fed WLO. Feeding linoleic and linolenic acids as unprotected oilseeds increased dry matter intake over time at a greater extent for cows fed MEG, improved the energy status, and lowered hepatic lipids and triacylglycerol contents, which may contribute to enhance the health status of transition dairy cows.

Effect of soya bean and fish oil inclusion in diets on milk and plasma enzymes from sheep and goat related to oxidation

This study investigated the effects of dietary inclusion of soya bean oil combined with fish oil (SFO) on the activities of a) superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT) and glutathione transferase (GST) in blood plasma and b) SOD, GR, CAT and lactoperoxidase (LPO) in the milk of sheep and goats. Furthermore, the oxidative stress indicators for measuring total antioxidant activity and free radical scavenging activity [ferric reducing ability of plasma (FRAP) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays] and oxidative stress biomarkers [malondialdehyde (MDA) and protein carbonyl (PC)] were also determined in the blood plasma and milk of the animals. For this purpose, twelve dairy sheep and twelve dairy goats were assigned each to two homogenous subgroups. Treatments in both animal species involved a control diet without added oil and a diet supplemented with 5% soya bean oil and 1% fish oil. The results showed that the inclusion of SFO in the diets of sheep and goats increased significantly the activities of CAT and GR in their blood plasma. The same effect was observed for the activities of GST and FRAP in the blood plasma of goats. Moreover, the fact that the goats had significantly higher average daily PUFA intake (3.62 g/kg BW^0.75 ) compared to sheep (2.51 g/kg BW^0.75 ) resulted in an enhancement in the MDA content in their plasma. A significant increase in CAT activity in the milk in both animal species fed with SFO diets was also found. Finally, due to the higher apparent transfer rate of n-3 FA from the diet to the milk in sheep, the PC concentrations were found to be enhanced in their plasma and milk. In conclusion, the impact of dietary SFO supplementation on the oxidative status of body and/or on the milk of small ruminants depends not only on the daily PUFA intake, but also on the amount of n-3 FA that reach their milk.

The etiology of oxidative stress in the various species of animals, a review

Oxidative stress is the consequence of an imbalance of pro-oxidants and antioxidants leading to cell damage and tissue injury. The exhaustion of antioxidant systems is one of the reasons for the occurrence of oxidative stress, which results in avalanche production of reactive oxygen species (ROS) or free radicals. High oxidative stress is common in organs and tissues with high metabolic and energy demands, including skeletal and heart muscle, liver and blood cells. Stress arises in animals in response to unavoidable or adverse environmental conditions. In the external environment, which affects the body of the cow, there are four main groups of stressors: physical, chemical, biological and psychological. Physical stressors include fluctuations in ambient temperature as well as mechanical injuries. High ambient temperature is one of the factors affecting the productivity of cows. Biological stressors are conditioned by errors and irregularities in habits. Both of these phenomena have an adverse impact on both the resistance of animals and fertility and are the etiological agent of oxidative stress. Various mechanisms may be responsible for metal-induced oxidative stress: direct or indirect generation of ROS, depletion of glutathione and inhibition of antioxidant enzymes are well known for all redox-active and redox-inactive metals.

Effect of abomasal or ruminal administration of citrus pulp and soybean oil on milk fatty acid profile and antioxidant properties

Soybean oil (SBO) is rich in polyunsaturated fatty acids (FA) and rumen bypass of SBO can contribute to increase the polyunsaturated FA proportion in milk fat. Citrus pulp (CPP) is a source of antioxidants but there is little information on the effects of CP administration on milk properties. This study was performed to determine the role of rumen microorganisms in the transfer of antioxidants from CPP into milk when cows receive SBO as a source of polyunsaturated FA. Four ruminally fistulated lactating Holstein cows were assigned to a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: (1) SBO administered in the rumen; (2) SBO infused in the abomasum; (3) SBO + CPP administered in the rumen; and (4) SBO + CPP infused in the abomasum. Product and site of administration had no effect on yield of milk components. Concentrations of total polyphenols and flavonoids, reducing power and production of conjugated diene (CD) hydroperoxides in milk were not affected by products, but infusion in the abomasum compared with administration in the rumen increased production of CD. Milk fat FA profile was not affected by products. However, cows infused in the abomasum compared with those administered in the rumen showed lower proportions of short-chain and monounsaturated FA and higher proportions of polyunsaturated, omega 3 and omega 6 FA in milk fat, which resulted in enhanced health-promoting index of milk. Administration of SBO and CPP (0.2 + 1.0 kg/d) in the rumen or the abomasum resulted in similar milk antioxidant properties, thus suggesting that the rumen microbes have little involvement in the metabolism of antioxidants from CPP.

mRNA Expression of lipogenic enzymes in mammary tissue and fatty acid profile in milk of dairy cows fed flax hulls and infused with flax oil in the abomasum

In the present study, the effect of flax hulls with or without flax oil bypassing the rumen on the expression of lipogenic genes in the mammary tissue of dairy cows was investigated. A total of eight dairy cows were used in a replicated 4 × 4 Latin square design. There were four periods of 21 d each and four treatments: control diet with no flax hulls (CONT); diet with 9·88 % flax hulls in the DM (HULL); control diet with 500 g flax oil/d infused in the abomasum (COFO); diet with 9·88 % flax hulls in the DM and 500 g flax oil/d infused in the abomasum (HUFO). A higher mRNA abundance of sterol regulatory element binding transcription factor, fatty acid (FA) synthase, lipoprotein lipase (LPL), PPARγ1, stearoyl-CoA desaturase (SCD) and acetyl-coenzyme A carboxylase-α was observed in cows fed HULL than in those fed CONT, and HUFO had the opposite effect. Compared with CONT, COFO and HUFO lowered the mRNA abundance of SCD, which may explain the lower proportions of MUFA in milk fat with flax oil infusion. The mRNA abundance of LPL in mammary tissue and proportions of long-chain FA in milk fat were higher in cows fed COFO than in those fed CONT. The highest proportions of trans FA were observed when cows were fed HULL. The present study demonstrates that flax hulls with or without flax oil infusion in the abomasum can affect the expression of lipogenic genes in the mammary tissue of dairy cows, which may contribute to the improvement of milk FA profile.

Mammary gene expression and activity of antioxidant enzymes and oxidative indicators in the blood, milk, mammary tissue and ruminal fluid of dairy cows fed flax meal

The effects of flax meal (FM) on the activity of antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT)) in the blood, mammary tissue and ruminal fluid, and oxidative stress indicators (thiobarbituric acid-reactive substances(TBARS) and 1,1-diphenyl-2-picrylhydrazyl-scavenging activity) in the milk, plasma and ruminal fluid of dairy cows were determined.The mRNA abundance of the antioxidant enzymes and oxidative stress-related genes was assessed in mammary tissue. A total of eight Holstein cows were used in a double 4 x 4 Latin square design. There were four treatments in the diet: control with no FM(CON) or 5% FM (5FM), 10% FM (10FM) and 15% FM (15FM). There was an interaction between treatment and time for plasma GPx and CAT activities. Cows supplemented with FM had a linear reduction in TBARS at 2 h after feeding, and there was no treatment effect at 0, 4 and 6 h after feeding. TBARS production decreased in the milk of cows fed the 5FM and 10FM diets. There was a linear increase in nuclear factor (erythroid-derived 2)-like 2 (NFE2L2) mRNA abundance in mammary tissue with FM supplementation.A linear trend for increased mRNA abundance of the CAT gene was observed with higher concentrations of FM. The mRNA abundance of CAT, GPx1, GPx3, SOD1, SOD2, SOD3 and nuclear factor of k light polypeptide gene enhancer in B-cells (NFKB) genes was not affected by the treatment. These findings suggest that FM supplementation can improve the oxidative status of Holstein cows as suggested by decreased TBARS production in ruminal fluid 2 h post-feeding and increased NFE2L2/nuclear factor-E2-related factor 2 (Nrf2) mRNA abundance in mammary tissue.

Effects of abomasal infusion of flaxseed (Linum usitatissimum) oil on microbial β-glucuronidase activity and concentration of the mammalian lignan enterolactone in ruminal fluid, plasma, urine and milk of dairy cows

Ruminal microbiota plays an important role in the conversion of plant lignans into mammalian lignans. The main mammalian lignan present in the milk of dairy cows fed flax products is enterolactone (EL). The objectives of the present study were to investigate the effects of abomasal infusion of flax oil on the metabolism of flax lignans and concentrations of EL in biological fluids of dairy cows. A total of six rumen-cannulated dairy cows were assigned within a 2 × 3 factorial arrangement of six treatments utilising flax hulls (0 and 15·9 % of DM) and abomasal infusion of flax oil (0, 250 and 500 g/d). There were six periods of 21 d each. Samples were collected during the last 7 d of each period and subjected to chemical analysis. Flax hull supplementation increased concentrations of EL in ruminal fluid, plasma, urine and milk, while flax oil infusion had no effect. Post-feeding, β-glucuronidase activity in the ruminal fluid of cows infused with 250 g flax oil was significantly lower for cows fed hulls than for those fed the control diet. The present study demonstrated that the presence of a rich source of n-3 fatty acids such as flax oil in the small intestine does not interfere with the absorption of the mammalian lignan EL and that lower ruminal β-glucuronidase activity had no effect on the conversion of flax lignans into EL in the rumen of dairy cows.