Dietary Administration of Olive Mill Wastewater Extract Reduces Campylobacter spp. Prevalence in Broiler Chickens

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.

Replacement of Vitamin E by an Extract from an Olive Oil By-Product, Rich in Hydroxytyrosol, in Broiler Diets: Effects on Growth Performance and Breast Meat Quality

The hypothesis of this experiment was that a liquid rich in hydroxytyrosol (HT) obtained from "alperujo", an olive oil by-product, could replace part of the added vitamin E (VE) as an antioxidant in poultry diets. There were five diets that differed exclusively in the substitution of supplemental VE (0 to 40 mg/kg, with differences of 10 mg/kg) by HT (30 to 0 mg/kg, with differences of 7.5 mg/kg). The basal diet was based on corn and soybean meal and provided 10 mg VE/kg. From 0 to 39 d of age, the growth performance of the birds was not affected by diet. The birds were slaughtered at 39 d of age to evaluate the quality of the breast, and malonaldehyde concentration, pH, color, and drip loss were measured. In terms of meat lipid oxidation, the combination of 22.5 mg HT/kg and 10 mg of added VE/kg equalized to a diet supplemented with 40 mg VE/kg. Meat color improved in broilers fed 7.5 mg HT/kg and 30 mg VE/kg. It is concluded that once the nutritional requirements of the birds in VE are satisfied, the dietary supplementation with the olive oil by-product rich in HT can be used as a strategy to spare VE in broiler diets.

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.

Replacement of Vitamin E by an Extract from an Olive Oil by-Product, Rich in Hydroxytyrosol, in Broiler Diets: Effects on Liver Traits, Oxidation, Lipid Profile, and Transcriptome

The study examines the effect of replacing vitamin E (VE) with a liquid obtained from alpeorujo, an olive oil by-product rich in hydroxytyrosol (HT), as an antioxidant in broiler chicken feeds on the gene expression, lipid profile, and oxidation in the liver. There were five diets that differed only in the substitution of supplemental VE (0 to 40 mg/kg with differences of 10 mg/kg) by HT (30 to 0 mg/kg with differences of 7.5 mg/kg). A linear decrease (p < 0.05) in α-tocopherol concentration in the liver was observed with the replacement of VE by HT. There were no significant changes in triglyceride, cholesterol, or TBARS concentrations. The hepatic transcriptome showed 378 differentially expressed genes between broilers fed HT15 (20 mg/kg VE and 15 mg/kg HT) and HT0 (40 mg/kg VE) diets (p < 0.05 and fold change less or higher than 1.3). Significant changes in cell cycle, cell nucleus activity, neuroactivity, and necroptosis pathways and functions were observed. It is concluded that the olive oil by-product, rich in HT, could be used to spare VE as an antioxidant in broiler diets without affecting liver lipid and TBARS concentrations. The differential gene expression analysis showed a potential role of olive polyphenols in enhancing the chicken immune response.

Dietary Olive Leaf Extract Differentially Modulates Antioxidant Defense of Normal and Aeromonas hydrophila-Infected Common Carp (Cyprinus carpio) via Keap1/Nrf2 Pathway Signaling: A Phytochemical and Biological Link

Olive leaves are an immense source of antioxidant and antimicrobial bioactive constituents. This study investigated the effects of dietary incorporation of olive leaf extract (OLE) on the growth performance, hematobiochemical parameters, immune response, antioxidant defense, histopathological changes, and some growth- and immune-related genes in the common carp (Cyprinus carpio). A total of 180 fish were allocated into four groups with triplicate each. The control group received the basal diet without OLE, while the other three groups were fed a basal diet with the OLE at 0.1, 0.2, and 0.3%, respectively. The feeding study lasted for 8 weeks, then fish were challenged with Aeromonas hydrophila. The results revealed that the group supplied with the 0.1% OLE significantly exhibited a higher final body weight (FBW), weight gain (WG%), and specific growth rate (SGR) with a decreased feed conversion ratio (FCR) compared to the other groups (p < 0.05). An increase in immune response was also observed in the fish from this group, with higher lysosome activity, immunoglobulin (IgM), and respiratory burst than nonsupplemented fish, both before and after the A. hydrophila challenge (p < 0.05). Similarly, the supplementation of the 0.1% OLE also promoted the C. carpio's digestive capacity pre- and post-challenge, presenting the highest activity of protease and alkaline phosphatase (p < 0.05). In addition, this dose of the OLE enhanced fish antioxidant capacity through an increase in the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and decreased hepatic lipid peroxidation end products (malondialdehyde-MDA), when compared to the control group, both pre- and post-infection (p < 0.05). Concomitantly with the superior immune response and antioxidant capacity, the fish fed the 0.1% OLE revealed the highest survival rate after the challenge with A. hydrophila (p < 0.05). A significant remarkable upregulation of the hepatic sod, nrf2, and protein kinase C transcription levels was detected as a vital approach for the prevention of both oxidative stress and inflammation compared to the infected unsupplied control group (p < 0.05). Interestingly, HPLC and UPLC-ESI-MS/MS analyses recognized that oleuropein is the main constituent (20.4%) with other 45 compounds in addition to tentative identification of two new compounds, namely oleuroside-10-carboxylic acid (I) and demethyl oleuroside-10-carboxylic acid (II). These constituents may be responsible for the OLE exerted potential effects. To conclude, the OLE at a dose range of 0.66-0.83 g/kg w/w can be included in the C. carpio diet to improve the growth, antioxidant capacity, and immune response under normal health conditions along with regulating the infection-associated pro-inflammatory gene expressions, thus enhancing resistance against A. hydrophila.

Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

Olive Leaf as a Source of Antibacterial Compounds Active against Antibiotic-Resistant Strains of Campylobacter jejuni and Campylobacter coli

Campylobacter spp. are the main cause of bacterial gastroenteritis worldwide, and broiler chicks are the main vector of transmission to humans. The high prevalence of Campylobacter in poultry meat and the increase of antibiotic resistant strains have raised the need to identify new antimicrobial agents. For this reason, the aim of the current study was to evaluate the antibacterial activity of two extracts of olive leaf against antibiotic-resistant Campylobacter strains (C. jejuni and C. coli) isolated from poultry food chain. The extracts of olive leaf (E1 and E2) were markedly different in their chemical compositions. While E1 was composed predominantly of highly hydrophilic compounds such as hydroxytyrosol and hydroxytyrosol glucosides (14,708 mg/100 g), E2 mainly contained moderately hydrophilic compounds, with oleuropein (20,471 mg/100 g) being prevalent. All Campylobacter strains exhibited similar antibiotic profiles, being resistant to ciprofloxacin and tetracycline. E1 showed strong antibacterial activity and reduced bacterial growth from 4.12 to 8.14 log CFU/mL, depending on the strain. Hydroxytyrosol was the main compound responsible, causing the inhibition of growth of Campylobacter strains at low concentrations (0.1-0.25 mg/mL). E2 demonstrated a lower antibacterial effect than E1, reducing growth from 0.52 to 2.49 log CFU/mL. The results of this study suggest that the optimization of the composition of olive-leaf extracts can provide improved treatment results against Campylobacter strains.

Dietary Supplementation of Olive Mill Waste Water Polyphenols in Rabbits: Evaluation of the Potential Effects on Hepatic Apoptosis, Inflammation and Metabolism through RT-qPCR Approach

Agro-industrial processing for the production of food or non-food products generates a wide range of by-products and residues rich in bioactive compounds including polyphenols. The concentration of these by-products is sometimes higher than in the original raw material as in the case of olive mill waste water (OMWW), one of the main by-products of olive oil extraction. Polyphenols are secondary plant metabolites that regulate the expression of specific inflammatory genes, transcriptional factors and pro/anti-apoptotic molecules, thus modulating the signaling pathways essential for cell health and homeostasis. The liver plays a key role in regulating homeostasis by responding to dietary changes in order to maintain nutritional and physiological states. In this study a nutrigenomic approach was adopted, which focuses on the effects of diet-health-gene interactions and the modulation of cellular processes, in order to evaluate the expression of the genes (AGER, BAX, COX2, IL1B, PPARA, PPARG, SIRT1, TNFA) involved in these interactions in the livers of rabbits fed with a diet supplemented with OMWW (POL) or without supplements (control, CTR). The RT-qPCR analysis showed the down-regulation of SIRT1, TNFA, AGER, BAX and PPARA transcripts in the POL group compared to the CTR group. These results show that OMWW dietary supplementation prevents cell death and tissue deterioration in rabbits.

Polyphenols and Organic Acids as Alternatives to Antimicrobials in Poultry Rearing: A Review

For decades antibiotics have been used in poultry rearing to support high levels of production. Nevertheless, several problems have arisen because of the misuse of antibiotics (i.e., antibiotic resistance, residues in animal products, environmental pollution). Thus, the European Union (EU) as well as the European Food Safety Authority (EFSA) promote action plans to diminish the use of antibiotics in animal production. Alternatives to antibiotics have been studied. Polyphenols (PPs) or organic acids (OAs) seem to be two accredited solutions. Phenolic compounds, such as phenols, flavonoids, and tannins exert their antimicrobial effect with specific mechanisms. In contrast, short chain fatty acids (SCFAs) and medium chain fatty acids (MCFAs), the OAs mainly used as antibiotics alternative, act on the pathogens depending on the pKa value. This review aims to collect the literature reporting the effects of these substances applied as antimicrobial molecules or growth promoter in poultry feeding (both for broilers and laying hens). Organic acids and PPs can be used individually or in blends, exploiting the properties of each component. Collected data highlighted that further research needs to focus on OAs in laying hens' feeding and also determine the right combination in blends with PPs.

Employment of Phenolic Compounds from Olive Vegetation Water in Broiler Chickens: Effects on Gut Microbiota and on the Shelf Life of Breast Fillets

Olive vegetation water (OVW) is a by-product with a noticeable environmental impact; however, its polyphenols may be reused food and feed manufacture as high-value ingredients with antioxidant/antimicrobial activities. The effect of dietary supplementation with OVW polyphenols on the gut microbiota, carcass and breast quality, shelf life, and lipid oxidation in broiler chickens has been studied. Chicks were fed diets supplemented with crude phenolic concentrate (CPC) obtained from OVW (220 and 440 mg/kg phenols equivalent) until reaching commercial size. Cloacal microbial community (rRNA16S sequencing) was monitored during the growth period. Breasts were submitted to culture-dependent and -independent microbiological analyses during their shelf-life. Composition, fatty acid concentration, and lipid oxidation of raw and cooked thawed breasts were measured. Growth performance and gut microbiota were only slightly affected by the dietary treatments, while animal age influenced the cloacal microbiota. The supplementation was found to reduce the shelf life of breasts due to the growth of spoilers. Chemical composition and lipid oxidation were not affected. The hydroxytyrosol (HT) concentration varied from 178.6 to 292.4 ug/kg in breast muscle at the beginning of the shelf-life period. The identification of HT in meat demonstrates that the absorption and metabolism of these compounds was occurring efficiently in the chickens.

Effects of Dietary Polyphenols from Olive Mill Waste Waters on Inflammatory and Apoptotic Effectors in Rabbit Ovary

The aim of this study was to evaluate the effect of dietary polyphenols on the expression of the effectors involved in inflammation and apoptosis in rabbit ovary. New Zealand White female rabbits were fed a basal control diet (CTR), or the same diet supplemented with a polyphenolic concentrate (POL, 282.4 mg/kg) obtained from olive mill waste waters. The follicle counts and the relative mRNA (RT-qPCR) and protein (immunohistochemistry) expression of the effectors involved in inflammation (cyclooxygenase-2; interleukin-1beta; tumor necrosis factor-alpha, TNFA) and apoptosis (BCL2-associated X protein, BAX), detected in the ovaries of both groups, were examined. The POL diet increased the primary and total follicles number. Cyclooxygenase-2 gene expression was higher (p < 0.05) in the POL group than in the CTR group, whereas BAX was lower (p < 0.05) in POL than CTR. Immunohistochemistry revealed the presence of all the proteins examined, with weaker (p < 0.05) COX2 and BAX signals in POL. No differences between the CTR and POL groups were observed for IL1B and TNFA gene and protein expression. These preliminary findings show that dietary polyphenols modulate inflammatory and apoptotic activities in rabbit ovary, regulating cyclooxygenase-2 and BAX expression, thus suggesting a functional involvement of these dietary compounds in mammalian reproduction.

Dietary Supplementation with Olive Mill Wastewater in Dairy Sheep: Evaluation of Cheese Characteristics and Presence of Bioactive Molecules

Simple Summary

Using polyphenols from olive oil waste as feed supplements in animal diets can be a strategy to reduce adverse environmental effects of this by-product and to enhance the quality of products of animal origin. The aim of the study was to assess the effects of adding a polyphenolic concentrate from olive oil wastewater to a typical sheep diet on the nutraceutical and quality characteristics of cheese. The experiment was carried out on thirty-six Sarda ewes, divided into two homogenous groups fed a standard diet composed of hay and concentrate. In one of the two diets, the concentrate was supplemented (25 g/kg) with polyphenols obtained from olive mill wastewater using a special filtration system. Data showed that the polyphenol supplementation in the ewe’s diet resulted in the presence of tyrosol and hydroxytyrosol sulphate metabolites in milk and cheese. Furthermore, these compounds were able to provide a direct antioxidant effect on cheese with no modification in its chemical composition.

Abstract

The aim of the study was to define the chemical characteristics, antioxidant capacity, oxidative status, sensory properties, and the presence of polyphenols in ovine cheese obtained after dietary administration of spray-dried olive mill wastewater (SDP). SDP is a waste from olive oil production rich in bioactive molecules obtained by further processing the olive mill wastewater through a spray-drying system. Thirty-six sheep were randomly assigned to two experimental groups that received a standard diet based on hay and concentrate. The concentrate fed to the SDP group was supplemented with SDP at a rate 25 g/kg (as fed). The trial lasted 9 weeks. Milk from the two treatment groups was separately collected and used for manufacturing cheese. Cheese quality parameters and proximate composition were not affected by the dietary treatment, whereas the antioxidant status and oxidative stability of cheese were positively affected. Polyphenol analyses in cheese were performed through liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The concentration of hydroxytyrosol and tyrosol, and their sulphate metabolites, were higher in cheese from supplemented sheep. These findings suggest that polyphenol metabolites can play a major role in the beneficial effects observed in food produced from sheep fed SDP.

Antimicrobial efficacy of a polyphenolic extract from olive oil by-product against "Fior di latte" cheese spoilage bacteria

This study aimed to evaluate a polyphenol extract from olive oil by-product, to improve the preservation of "Fior di latte" cheese during storage. Nine batches of "Fior di latte" cheese were manufactured in a local dairy production plant: three batches treated with 250 μg/mL of phenols from olive oil by-products in the governing liquid; three batches treated with 500 μg/mL of phenols in the governing liquid, and three untreated batches as the control group. The phenols effectively retarded the growth of Pseudomonas fluorescens and Enterobacteriaceae, acting mainly on the lag phase of the microorganisms, resulting in the prolongation of the time needed to reach the acceptable microbial limit. The delay in the growth of the spoilage bacteria was considered to indirectly influence the sensorial acceptability threshold, recorded through survival analysis. The combination of the two above-mentioned factors promotes the extension of "Fior di latte" cheese shelf life. by >2 and 4 days, for PA and PB respectively.

Dietary supplementation with olive mill wastewaters induces modifications on chicken jejunum epithelial cell transcriptome and modulates jejunum morphology

BACKGROUND

The Mediterranean diet is considered one of the healthier food habits and olive oil is one of its key components. Olive oil polyphenols are known to induce beneficial effects in several pathological conditions, such as inflammatory bowel disease, and to contrast the proliferation of cancer cells or hypercholesterolemia. Polyphenols are also present in waste products derived from the olive industry: olive mill wastewaters (OMWW) are rich in polyphenols and there is an increasing interest in using OMWW in animal nutrition. OMWW are attributed with positive effects in promoting chicken performance and the quality of food-derived products. However, a tissue-specific transcriptome target analysis of chickens fed with OMWW has never been attempted.

RESULTS

We explored the effect of dietary OMWW on the intestinal function in broilers. A morphological analysis of the jejunum revealed that OMWW reduced crypt depth, whereas no significant modifications were observed for villus height and the villus height/crypt depth ratio. An RNA Sequencing analysis was performed on isolated, intestinal, epithelial cells and 280 differentially expressed genes were found using a count-based approach. An enrichment analysis revealed that the majority of up regulated genes in the OMWW group were over-represented by the regulation of viral genome replication-related GO-Terms, whereas down regulated genes were mainly involved in cholesterol and lipid metabolism.

CONCLUSIONS

Our study showed how an industrial waste product can be recycled as a feed additive with a positive relapse. OMWW dietary supplementation can be a nutritional strategy to improve chicken performance and health, prevent intestinal damage, enhance innate immunity and regulate cholesterol metabolism and fat deposition.