Influence of polyphenols from olive mill wastewater on the gastrointestinal tract, alveolar macrophages and blood leukocytes of pigs

Morphological digital assessment and transcripts of gastric and duodenal visfatin in growing piglets fed with increasing amounts of polyphenols from olive mill waste extract

Visfatin is an adipokine with mediatory effects on inflammation. It is expressed at low levels in the pig stomach, but its role in the gastrointestinal (GI) tract is not well understood. This study explored visfatin expression and localisation in the stomach and duodenum of piglets fed varying levels of polyphenols derived from olive mill waste extract, known for their antioxidant and immunomodulatory properties. Twenty-seven piglets were assigned to three dietary groups: control (commercial feed), low polyphenol (120 ppm), and high polyphenol (240 ppm) groups. After 14 days of feeding, samples from the glandular stomach and duodenum were collected from 13 piglets. Immunohistochemistry (IHC), digital image analysis (DIA) using QuPath software, and double-labelled immunofluorescence were performed to detect visfatin-positive cells and co-localise them with serotonin. Additionally, relative gene expression of visfatin was assessed via RT-qPCR. Visfatin-positive cells were identified in 5 out of 13 piglets, localised mainly in the basal portion of gastric and intestinal glands. The morphology of those cells was consistent with neuroendocrine cells and confirmed by co-localisation of visfatin and serotonin. No significant differences were found in cell positivity or morphology between dietary groups or between tissues. However, visfatin transcript levels increased with the dose of polyphenolic extract. These findings suggest that dietary polyphenols may modulate visfatin gene expression in the GI tract. The study also highlights the value of digital anatomy for enhancing the accuracy and reproducibility of anatomical research. Further studies are needed to elucidate the functional role of visfatin transcript and protein in the porcine GI tract.

A Diet Supplemented with Oil-Free Olive Pulp Flour (MOP-ManniOlivePowder®) Improves the Oxidative Status of Dogs

Olive oil coproducts and their phenolic extracts have shown beneficial effects when added to the diets of food-producing animals, whereas data on their effects on pets are scarce. The aim of this study was to evaluate the effects of dietary supplementation with olive flour (MOP®) on oxidative blood biomarkers in dogs. Thirty dogs were recruited and divided into two groups. Both groups were fed the same kibble feed twice daily. The treatment group (T) also received canned wet feed supplemented with 11.5 mg/kg of body weight of organic olive flour per day, whereas the control group (C) received the same wet feed without any supplementation. The findings showed that oil-free olive pulp flour supplementation led to a significant decrease in d-ROMs (p < 0.044) in the blood of the T group (from 101.26 to 86.67 U CARR), whereas no significant changes were observed in the C group. An increasing OXY trend was found in the blood of the T group. Polyphenols in olive flour at a dose of 11.5 mg/kg of body weight contributed to lowering the oxidative stress threshold in dogs, reducing the levels of d-ROMs in dogs and leading to increasing trends in the amount of blood antioxidants. The use of olive pulp flour in dog diets has proven to be beneficial for their health and could also reduce the waste associated with olive oil production.

Olive Mill Waste-Water Extract Enriched in Hydroxytyrosol and Tyrosol Modulates Host-Pathogen Interaction in IPEC-J2 Cells

The dietary supplementation of olive oil by-products, including olive mill waste-water (OMWW) in animal diets, is a novel application that allows for their re-utilization and recycling and could potentially decrease the use of antibiotics, antimicrobial resistance risk in livestock species, and the occurrence of intestinal diseases. Salmonella serovar typhimurium is one of the most widespread intestinal pathogens in the world, causing enterocolitis in pigs. The aim of this study was to investigate the effect of an OMWW extract enriched in polyphenols (hydroxytyrosol and tyrosol) in the immune response of an intestinal porcine epithelial cell line (IPEC-J2) following S. typhimurium infection. Cells were pre-treated with OMWW-extract polyphenols (OMWW-EP, 0.35 and 1.4 µg) for 24 h and then infected with S. typhimurium for 1 h. We evaluated bacterial invasiveness and assayed IPEC-J2 gene expression with RT-qPCR and cytokine release with an ELISA test. The obtained results showed that OMWW-EP (1.4 µg) significantly reduced S. typhimurium invasiveness; 0.35 µg decreased the IPEC-J2 gene expression of IL1B, MYD88, DEFB1 and DEFB4A, while 1.4 µg down-regulated IL1B and DEFB4A and increased TGFB1. The cytokine content was unchanged in infected cells. This is the first study demonstrating the in vitro immunomodulatory and antimicrobial activity of OMWW extracts enriched in polyphenols, suggesting a protective role of OMWW polyphenols on the pig intestine and their potential application as feed supplements in farm animals such as pigs.

Effects of Olea europaea L. Polyphenols on the Animal Welfare and Milk Quality in Dairy Cows

Here, we evaluated the effect of dietary supplementation with an Olea europaea L. extract on the animal welfare and milk quality of dairy cows. Thirty Italian Holstein-Friesian dairy cows in the mid-lactation phase (90 to 210 days) were blocked into experimental groups based on parity class (namely, primiparous (P) (n = 10), secondiparous (S) (n = 10) and pluriparous (PL) (n = 10)) and received, for 60 days, Phenofeed Dry® at 500 mg/cow/day. Milk and blood samples were collected before the start of the treatment (T0), subsequently every 15 days (T1-T4) and at 45 days after the end of treatment (T5). In the serum, glucose and triglycerides, stress, the thyroid, lactation and sex hormones were measured; in the milk, lysozyme content as well as the fatty acid profile were assessed. In the whole animal, the enriched feed helped to maintain hormonal parameters in the physiological range while producing hypoglycemic (T4 vs. T0, for P and PL p < 0.001) and hypolipidemic effects (T4 vs. T0, for P p < 0.001 and for PL p < 0.01). At the milk level, it resulted in a reduction in total fat (T5 vs. T0, for P, S and PL p < 0.001) and in the saturated fatty acids (SFAs)/monounsaturated fatty acids (MUFAs) ratio paralleled by an increase in polyunsaturated fatty acids (PUFAs) (T5 vs. T0, for P, S and PL p < 0.001), protein content (lysozyme (T4 vs. T0, for P and PL p < 0.001)) and lactose (T5 vs. T0, for P, S and PL p < 0.001). Thus, the inclusion of natural bioactive molecules such as O. europaea L. polyphenols in the dairy cow diet may help to improve animal welfare and milk quality.

Dietary supplementation with olive oil co-products rich in polyphenols: a novel nutraceutical approach in monogastric animal nutrition

In recent years, the increased demand for agri-food products to feed livestock species has stimulated research to identify novel solutions for the valorization of natural waste, according to the modern concept of a circular economy. Numerous studies have shown the use of plant-derived and agro-industrial co-products that are sources of bioactive molecules for preparing animal feeds. Supplementation with co-products derived from the extraction of olive oil (i.e., olive pomace, olive mill wastewater, olive cake and olive leaf) in diet has been widely considered in recent decades, because these wastes are produced in high quantity and their re-use represents an innovative economic and environmental strategy. Olive oil co-products are characterized by various bioactive molecules such as polyphenols, carbohydrates, proteins, and lipids. Among them, polyphenols are the nutraceuticals most studied, showing to promote health effects in both humans and animals. Olive oil co-products and their phenolic extracts have shown many beneficial and promising effects when added to the diets of monogastric animals, by improving performance parameters and maintaining the oxidative status of meat and derived products. This review provides an update on the use of olive co-products in monogastric animal (swine, poultry and rabbit) diets and their effects on the productive performance, meat quality characteristics and gut health status.

Innovative Use of Olive, Winery and Cheese Waste By-Products as Novel Ingredients in Weaned Pigs Nutrition

New sustainable sources of feeds, which can enhance the health and welfare of farm animals, lower feeding costs, and lead to safer products, are of high priority in modern animal production systems. In the present study, a novel silage created from Greek olive, winery, and feta cheese waste by-products, was evaluated as a feed ingredient at different inclusion rates (0%, 5% or 10%) in 34-day-old weaned pigs. The potential beneficial effects on performance, health and intestinal digesta microflora balance of the pigs were evaluated. Additionally, chemical, microbiological and quality analysis of the meat was carried out. Results showed no detrimental effects (p > 0.05) on the pigs' performance and no significant changes (p > 0.05) in meat pH, color and chemical analysis. Ileum and cecum microflora populations (total anaerobes, Lactobacillaceae) were positively affected (p ≤ 0.05) by the dietary usage of the silage. The microbial populations (Clostridium spp.) of belly meat cuts were positively modified (p ≤ 0.01). The concentration of total phenols in the meat cuts were increased (p ≤ 0.05) and their resistance to oxidation was improved (p ≤ 0.05). In addition, the fatty acid profile of the meat lipids (polyunsaturated and n-3 fatty acids) was positively modified (p ≤ 0.001).

Dietary Supplementation with a Blend of Hydrolyzable and Condensed Tannins Ameliorates Diet-Induced Intestinal Inflammation in Zebrafish (Danio rerio)

The current study evaluated the effects of hydrolyzable and condensed tannins from chestnut and quebracho wood, respectively (TSP, Silvafeed^®), on zebrafish with intestinal inflammation induced by a plant-based diet (basal diet). Four experimental diets were prepared as follows: the basal diet + 0 TSP, the basal diet + TSP at 0.9 g/kg of feed, the basal diet + TSP at 1.7 g/kg of feed, and the basal diet + TSP at 3.4 g/kg of feed. Eighty-four zebrafish (Danio rerio) were fed for 12 days with the experimental diets. In zebrafish fed the basal diet, intestine integrity appeared to be altered, with damaged intestinal villi, high immunoexpression of tumor necrosis factor-α (TNFα) and cyclooxygenase 2 (COX2), and high expression of the cox2, interleukin 1 (il-1b), interleukin 8 (cxcl8-l1), and tnfα genes. The tannin treatment partially restored intestinal morphology and downregulated the expression of cytokines. The best activity was detected with 1.7 and 3.4 g/kg of feed. In the guts of all groups, Proteobacteria, Fusobacteria, Firmicutes, and Bacteroidetes were the most represented phyla. The most represented genera were Plesiomonas and Sphingomonas, belonging to the Proteobacteria phylum; Cetobacterium, belonging to the Fusobacteria phylum; and Lactobacillus, belonging to the Firmicutes phylum. No significant differences were detected among groups, except for a slight decrease in the Fusobacteria phylum and slight increases in the Shewanella and Bacteroides genera with TSP. In conclusion, these results suggest that tannins can improve the zebrafish intestinal inflammation caused by a terrestrial-plant-based diet in a dose-dependent manner.

Olive Mill Wastewater as Renewable Raw Materials to Generate High Added-Value Ingredients for Agro-Food Industries

Olive oil production represents an agro-industrial activity of vital economic importance for many Mediterranean countries. However, it is associated with the generation of a huge amount of by-products, both in solid and liquid forms, mainly constituted by olive mill wastewater, olive pomace, wood, leaves, and stones. Although for many years olive by-products have only been considered as a relevant environmental issue, in the last decades, numerous studies have deeply described their antioxidant, anti-inflammatory, immunomodulatory, analgesic, antimicrobial, antihypertensive, anticancer, anti-hyperglycemic activities. Therefore, the increasing interest in natural bioactive compounds represents a new challenge for olive mills. Studies have focused on optimizing methods to extract phenols from olive oil by-products for pharmaceutical or cosmetic applications and attempts have been made to describe microorganisms and metabolic activity involved in the treatment of such complex and variable by-products. However, few studies have investigated olive oil by-products in order to produce added-value ingredients and/or preservatives for food industries. This review provides an overview of the prospective of liquid olive oil by-products as a source of high nutritional value compounds to produce new functional additives or ingredients and to explore potential and future research opportunities.

In Vivo Screening and Antidiabetic Potential of Polyphenol Extracts from Guava Pulp, Seeds and Leaves

Simple Summary

The incidence of diabetes has risen from 151 million people in 2000 to 463 million in 2019, with 4.2 million estimated deaths in 2019, and over 700 million people will be affected with diabetes worldwide by 2045. Thus, the screening of anti-diabetic plants is inevitable in order to overcome diabetes. This study has investigated the anti-diabetic potential of polyphenol extracts from guava leaves, seeds and pulp using an albino rat model. The in vivo study has reported that polyphenols from leaves and pulp have an ability to improve diabetic parameters, such as insulin, blood glucose and triglycerides levels. The improvement in blood parameters is also an indication of these extracts that are valuable for diabetes management. The findings of this study reveal that polyphenols from guava leaves, pulp and seeds can be used for drug development.

Abstract

The present study investigates the antidiabetic potential of polyphenol extracts purified from guava pulp, seeds and leaves using an in vivo experiment on albino rats. The polyphenols from guava pulp, seeds and leaves were extracted using methanol solvent and the sonication method while being evaluated by total phenolic contents and radical scavenging activity assay. The proximate composition of powders revealed that ash, protein and total sugars were significantly (p < 0.05) higher in leaves and seeds, while vitamin C was highest in pulp. Total phenolic and antioxidant activities were highest in pulp followed by leaves and seeds. The findings of feed intake and body gain revealed that the supplementation of polyphenols, especially from pulp, significantly (p < 0.05) increased the feed intake, which resulted in increased body weight. Moreover, total cholesterol (TC) and low-density lipoprotein (LDL) levels were significantly (p < 0.05) decreased, while the level of high-density lipoprotein (HDL) was increased in groups fed with polyphenols from guava pulp compared to both (+ive and –ive) control groups. Furthermore, blood glucose and triglycerides were significantly (p < 0.05) decreased in supplemented groups compared to the control group of diabetes mice, which resulted in the inhibition of α-amylase and glucose transport. Besides this, packed cell volume (PCV), mean corpuscular volume (MCV), hemoglobin, red blood cells (RBCs), white blood cells (WBCs) and platelet levels were increased significantly (p < 0.05) in pulp’s extract followed by leaves and seeds compared to both control groups. Overall, the antidiabetic potential of different extracts was in the following order: pulp > leaves > seeds. The findings suggest the feasibility of adding 200–250 mg/kg.bw of polyphenol extracts of pulp as an alternative to diabetic drugs.

The Impact of Polyphenol on General Nutrient Metabolism in the Monogastric Gastrointestinal Tract

Polyphenols are bioactive compounds occurring in plant foods, which are considered significant owing to their contribution to human health and the prevention of chronic diseases. Phenolic compounds mainly depend on plant food structure and the interaction with other food constituents, mostly proteins, lipids, and carbohydrates. The interaction with the food matrices can obstruct or enhance nutrient accessibility and availability and even impair others. Food digestion is a complex process where ingested foods are converted to nutrients via mechanical and enzymatic alterations. The absorption of nutrients predominantly occurs in the small and large intestine, respectively. The metabolised product, however, is the main bioactive component due to their ability to enter the systemic circulation and reach the targeted organs. There is limited knowledge on the cellular uptake, phenolic metabolite, and polyphenolic effect in the gastrointestinal ecosystem. Therefore, improved understanding of the biological properties and stages of dietary phenols is essential for the effective utilization of their therapeutic potentials. This review will explore, summarise, and collate current information on how polyphenols influence nutrient metabolism, bioavailability, and the biotransformation stages.

Diet Supplementation with a Bioactive Pomace Extract from Olea europaea Partially Mitigates Negative Effects on Gut Health Arising from a Short-Term Fasting Period in Broiler Chickens

The effects of supplementing chicken diets with an olive pomace extract (OE) from Olea europaea on performance and gut health after a challenge of intestinal permeability (IP) increase were studied. Treatments included a control diet with no additives (CF), and diets supplemented with 100 ppm of monensin (MF) or with 500 (OE500F) and 1500 ppm (OE1500F) of an OE. At 14 d, all birds, except those allocated in a control group (CNF), were submitted to a 15.5 h short-term fasting period to induce IP increase. Fasting increased (p < 0.05) lactulose/mannitol ratio and Alpha 1 Acid Glycoprotein concentration, and reduced (p < 0.001) villus/crypt ratio. Moreover, a down-regulation of Claudin-1 (p < 0.05), an up-regulation of TLR4 and IL-8 (p < 0.05) ileal gene expression was observed in CF birds compared to CNF. OE500F treatment reduced duodenal crypt depth compared to CF (p < 0.05; OE linear effect). Mannitol concentration and ileal IL-8 expression were reduced in OE500F compared to CF and OE1500F (p = 0.05). Fasting challenge induced an increase in IP triggering an inflammatory response. Supplementation of OE up to 1500 ppm did not affect growth performance and alleviated some of the negative effects of the fasting challenge.

Changes in Plasma Fatty Acids, Free Amino Acids, Antioxidant Defense, and Physiological Stress by Oleuropein Supplementation in Pigs Prior to Slaughter

Olive tree leaves are characterized for having not only a potent antioxidant power but also effects on glucose and lipid metabolism. The impact of the individual oleuropein (OLE), vitamin E + Se (VE), or a combined supplementation of oleuropein, vitamin E, and selenium (VEOLE) was evaluated on pig plasma metabolites under fasting prior to slaughter. VEOLE and OLE had lesser n-3 plasma polyunsaturated fatty acids and greater monounsaturated free fatty acids compared to control. The n-3-fatty acid mobilization was directly correlated with greater cystine and inversely with oxidized glutathione/reduced glutathione (GSSH/GSH) levels. This faster use of n-3 fatty acids might act as an indicator of glutathione synthesis mediated by an increase of cystine in plasma. Different correlations and linear adjustments were observed between plasma antioxidant power and free cystine, free glycine, free glutamine, monounsaturated free fatty acids, and total n-3. The best response to stress was found in VEOLE. Cortisol reached the greatest positive correlation with plasma total n-3 fatty acids, which suggests a faster uptake of n-3 for biological functions such as stress control or energy supply in the brain. From a practical point of view, an enhanced oxidative status as well as control of physiological stress prior to slaughter by the combined antioxidants supplementation might have positive effects on pork quality.

UHPLC-HR-MS/MS-Guided Recovery of Bioactive Flavonol Compounds from Greco di Tufo Vine Leaves

Leaves of Vitis vinifera cv. Greco di Tufo, a precious waste made in the Campania Region (Italy), after vintage harvest, underwent reduction, lyophilization, and ultrasound-assisted maceration in ethanol. The alcoholic extract, as evidenced by a preliminary UHPLC-HR-MS analysis, showed a high metabolic complexity. Thus, the extract was fractionated, obtaining, among others, a fraction enriched in flavonol glycosides and glycuronides. Myricetin, quercetin, kaempferol, and isorhamnetin derivatives were tentatively identified based on their relative retention time and TOF-MS² data. As the localization of saccharidic moiety in glycuronide compounds proved to be difficult due to the lack of well-established fragmentation pattern and/or the absence of characteristic key fragments, to obtain useful MS information and to eliminate matrix effect redundancies, the isolation of the most abundant extract's compound was achieved. HR-MS/MS spectra of the compound, quercetin-3-O-glucuronide, allowed us to thoroughly rationalize its fragmentation pattern, and to unravel the main differences between MS/MS behavior of flavonol glycosides and glycuronides. Furthermore, cytotoxicity assessment on the (poly)phenol rich fraction and the pure isolated compound was carried out using central nervous system cell lines. The chemoprotective effect of both the (poly)phenol fraction and quercetin-3-O-glucuronide was evaluated.

In Vitro Fermentation and Chemical Characteristics of Mediterranean By-Products for Swine Nutrition

Simple Summary

By-products are residues obtained from agriculture and/or industrial processes, considered as wastes that could be used in animal nutrition. They are considered valid instruments to reduce feeding costs and breeding environmental impact. These residues may contain beneficial molecules that could be naturally transferred to animal products. In this study, the nutritional characteristics of eight by-products derived from citrus fruit juice (three pulps and two molasses) and olive oil (three olive cake) processes are evaluated for their possible use in pig diets. The chemical composition and fermentation parameters are different when comparing the citrus fruits and olive oil by-products. The citrus by-products are rich in fermentable carbohydrates, while olive oil by-products are rich in un-fermentable carbohydrates and fat. In any case, all the by-products categories show interesting nutritional characteristics. By-products typical of the Mediterranean area could be use in pig nutrition and could be considered an effective system to reduce animal production costs and limit the environmental impact of some production systems.

Abstract

The purpose of the study is to determine the nutritional characteristics of some by-products derived from fruit juice and olive oil production to evaluate their use in pig nutrition. Five by-products of citrus fruit (three citrus fruit pulp and two molasses) and three by-products of olive oil (olive cake) obtained by different varieties are analysed for chemical composition. The fermentation characteristics are evaluated in vitro using the gas production technique with swine faecal inoculum. All the citrus by-products are highly fermentable, producing gas and a high amount of short-chain fatty acids. The fermentation kinetics vary when comparing pulps and molasses. Citrus fruit pulps show lower and slower fermentation rates than molasses. The olive oil by-products, compared to citrus fruits ones, are richer in NDF and ADL. These characteristics negatively affect all the fermentation parameters. Therefore, the high concentration of fiber and lipids represents a key aspect in the nutrition of fattening pigs. The preliminary results obtained in this study confirm that the use of by-products in pig nutrition could represent a valid opportunity the reduce the livestock economic cost and environmental impact.