Phytogenic pigments in animal nutrition: potentials and risks

Phytogenic feed additives as natural antibiotic alternatives in animal health and production: A review of the literature of the last decade

The use of antibiotics in animal production raises great public safety concerns; therefore, there is an urgent need for the development of substitutes for antibiotics. In recent decades, plant-derived feed additives have been widely investigated as antibiotic alternatives for use in animal health and production because they exert multiple biological functions and are less likely to induce resistance development. This review summarizes the research history and classification of phytogenic feed additives and their main functions, potential modes of action, influencing factors, and potential negative effects. Further, we highlight the challenges in developing sustainable, safe, and affordable plant-derived antibiotic alternatives for use in livestock production.

Use of zinc nanoparticles and/or prodigiosin to mitigate heat stress in rabbits

Heat stress (HS) is an environmental challenge affecting animals' health, productivity and welfare. This work aimed to inspect the protective effect of zinc oxide nanoparticles (ZnNPs) and/or prodigiosin (PRG) against inflammation, immune dysfunction, oxidative stress and endoplasmic reticulum (ER) stress triggered by HS in growing rabbits. Growing weaned rabbits (one hundred males, 35 days of age) were randomly assigned into four groups. The first group fed a basal diet without supplementation and the 2nd, 3rd, and 4th groups fed diets containing zinc oxide nanoparticles (ZnNPs, 50mg/kg diet), prodigiosin (PRG, 100 mg/kg diet) or their mixture (ZnPRG) under HS conditions for eight successive weeks. The dietary inclusion with ZnNPs and/or PRG significantly boosted FBW (final body weight), CBWG (cumulative body weight gain), and FCR (feed conversion ratio) and had no substantial impacts on the CFI (cumulative feed intake) as compared with those in HS one. All supplemented treatments significantly unveiled an increase in the values of RBCs, hemoglobin, and platelets and significantly decreased in WBCs, basophils and monocytes with non-statistically effects on hematocrit, MCV, MCHC, neutrophils and eosinophils. Compared with the HS group, all supplemental groups showed a significant reduction in TNFα, IL4, IFN-γ, TLR-4 and amyloid A levels and DNA damage markers (Ohdg) and significantly increased in the levels of NO and lysosome activity. Rabbits in the ZnPRG group had significantly higher Ig G and Ig M levels than in other groups. The highest value of CAT and GSH levels were found in rabbits received the mixture of ZnNPs (50mg) and PRG (100mg) in their diets under elevated temperatures. Additionally, both treatments, PRG and ZnNPS, significantly (P<0.001) reduced the values of MDA and MYO, while all treated groups had significantly reduced PC contents compared with the HS group. Co-supplement with ZnPRG showed a considerable restoration in the higher immune expression of reticulum oxidative such GRP78 and IRE1 in hepatic tissues induced by HS conditions. The mixture of ZnNPs and PRG presented more robust effects in mitigating the adverse impacts of HS in rabbits compared with the individual treatments. Collectively, ZnNPs and/or PRG alleviated oxidative stress and DNA damage. In addition, it enhanced the antioxidant capacity and immune function, and downregulated ER stress such as GRP78 and IRE1 signaling in the hepatic tissues of stressed rabbits.

Current Development and Future Application Prospects of Plants-Derived Polyphenol Bioactive Substance Curcumin as a Novel Feed Additive in Livestock and Poultry

Curcumin (CUR) is a kind of natural orange-yellow phenolic compound mainly extracted from the stems and roots of turmeric plants and other species in the genus Curcuma, furthermore, it is also the most important active ingredient exerting pharmacological functions in turmeric. In recent years, CUR has been frequently reported and has attracted widespread attention from scholars all over the world due to its numerous biological functions and good application prospects, such as anti-inflammatory, anticancer, antioxidant and providing lipid-lowering effects, etc. In addition, adding a certain dose of CUR to livestock and poultry feed is important for animal growth and development, which plays a key role in animal metabolism, reproduction, immunity and clinical health care. This review aims to summarize, based on the published papers and our own observations, the physical and chemical properties and the biological functions of the plant-derived bioactive ingredient CUR, especially regarding the latest research progress in regulating intestinal health as well as its current development and future application prospects in livestock and poultry as a novel feed additive, so as to provide theoretical and practical references for the further study of the application of CUR as a novel feed additive and a potential new antibiotic substitute, thereby improving the research field of plant-derived bioactive ingredients and promoting the healthy development of livestock and poultry.

Natural and synthetic pigments in sorghum-based diets for laying hens

The objective of this work was to evaluate the supplementation of yellow natural pigment levels based on Marigold Flower extract (2%) and yellow synthetic pigment (Carophyll Yellow 10%) in sorghum-based rations for commercial laying hens and their influence on bird performance and egg quality. A completely randomized design was adopted with 5 treatments, 6 replicates, and 5 laying hens in each repetition. The treatments evaluated were: Sorghum based diet without supplementation with pigmentant - Negative Control; 150 g t-1 of Yellow Natural Pigment feed; 300 g t-1 of yellow natural pigment feed; 450 g t-1 of yellow natural pigment feed; 25 g t-1 of yellow industrial pigment feed. The Tukey test was applied at 5% for the analysis of the variables of performance and quality of the eggs. The variables related to external and internal egg quality and poultry yield performance did not present significant results (p > 0.05). Only the variable color of the yolk obtained significance (p < 0.01), with an increase according to the number of pigments included in the diet. Sorghum can be used together supplementation of natural and synthetic pigments in the diet to improve yolk pigmentation. It is recommended to include 450g t-1 of natural marigold flower pigment feed (2%) in sorghum-based diets for better pigmentation of the yolk in place of 25 g t-1 of yellow synthetic pigmented, by improving the color of the yolk and not interfering in the productive performance of the laying hens and the quality of the eggs.

Phytogenic Compounds for Enhancing Intestinal Barrier Function in Poultry-A Review

After the European Union ban of antibiotic growth promoters, works on different methods of improving gut health have intensified. The poultry industry is struggling with problems that were previously controlled by antibiotic growth promoters, therefore the search for optimal solutions continues. Simultaneously, there is also increasing social pressure to minimize the use of antibiotics and replace them with alternative feed additives. A variety of available alternatives is considered safe by consumers, among which phytogenics play a significant role. However, there are still some limitations that need to be considered. The most questionable are the issues related to bioavailability, metabolism of plant derivatives in birds, and the difficulty of standardizing commercial products. There is still a need for more evidence-based recommendations for the use of phytogenics in livestock. On the other hand, a positive influence of phytogenic compounds on the health of poultry has been previously described by many researchers and practical application of these compounds has auspicious perspectives in poultry production. Supplementation with phytogenic feed additives has been shown to protect birds from various environmental threats leading to impaired intestinal barrier function. Phytogenic feed additives have the potential to improve the overall structure of intestinal mucosa as well as gut barrier function on a molecular level. Recognition of the phytogenics' effect on the components of the intestinal barrier may enable the selection of the most suitable ones to alleviate negative effects of different agents. This review aims to summarize current knowledge of the influence of various phytogenic constituents on the intestinal barrier and health of poultry.

The neuroprotective effect of curcumin against ATO triggered neurotoxicity through Nrf2 and NF-κB signaling pathway in the brain of ducks

Arsenic trioxide (ATO) has confirmed as a global pollutant, the toxic effect of which was not fully understood and lack effective therapies to against its associated toxicities. Curcumin (Cur) is a beneficial natural pigment for its antioxidant and anti-inflammatory properties. The purpose of this paper was to illustrate the antagonism of Cur against ATO-induced neurotoxicity. A total of 40 ducks were divided randomly into 4 groups and conducted via bite and sup for 28 days: control group (Control); 2 mg/kg ATO group (Low ATO); 4 mg/kg ATO group (Middle ATO); 8 mg/kg ATO group (High ATO); 400 mg/kg Cur group + 8 mg/kg ATO (Cur+ATO). The results showed that ATO exposure can hinder the duck growth and arsenic element accumulation rate increased in a dose-dependent manner. We observed neuronal shrinkage and vacuolize of HE staining in the ATO-treated group. In addition, SOD activity and T-AOC level reduced while MDA content increased in the ATO-exposed group. ATO exposure can decrease the expression of anti-oxidation related mRNA and proteins (Nrf2, SOD-1, GPX-1, CAT, Trx and HO-1) and anti-inflammatory makers (IL-4, IL-10), increased the expression of Keap1, NF-κB and pro-inflammatory makers (TNF-α, IL-1β, IL-18, IL-2, IL-6, INOS and COX-2). ATO treated might cause blood-brain barrier (BBB) damage through degradation of the tight junction proteins (TJs) occludin and ZO-1. Importantly, the experimental results also showed that Cur can alleviate oxidative stress, inflammatory response and BBB injury caused by ATO exposure through Nrf2 and NF-κB signaling pathway. The results suggested Cur exerted as a food additive and provided novel potential benefits of ATO toxicology in inflammation of the brain.

Properties of Carotenoids in Fish Fitness: A Review

Carotenoids, one of the most common types of natural pigments, can influence the colors of living organisms. More than 750 kinds of carotenoids have been identified. Generally, carotenoids occur in organisms at low levels. However, the total amount of carotenoids in nature has been estimated to be more than 100 million tons. There are two major types of carotenoids: carotene (solely hydrocarbons that contain no oxygen) and xanthophyll (contains oxygen). Carotenoids are lipid-soluble pigments with conjugated double bonds that exhibit robust antioxidant activity. Many carotenoids, particularly astaxanthin (ASX), are known to improve the antioxidative state and immune system, resulting in providing disease resistance, growth performance, survival, and improved egg quality in farmed fish without exhibiting any cytotoxicity or side effects. ASX cooperatively and synergistically interacts with other antioxidants such as α-tocopherol, ascorbic acid, and glutathione located in the lipophilic hydrophobic compartments of fish tissue. Moreover, ASX can modulate gene expression accompanying alterations in signal transduction by regulating reactive oxygen species (ROS) production. Hence, carotenoids could be used as chemotherapeutic supplements for farmed fish. Carotenoids are regarded as ecologically friendly functional feed additives in the aquaculture industry.

Acute, reproductive, and developmental toxicity of essential oils assessed with alternative in vitro and in vivo systems

Essential oils (EOs) have attracted increased interest for different applications such as food preservatives, feed additives and ingredients in cosmetics. Due to their reported variable composition of components, they might be acutely toxic to humans and animals in small amounts. Despite the necessity, rigorous toxicity testing in terms of safety evaluation has not been reported so far, especially using alternatives to animal models. Here, we provide a strategy by use of alternative in vitro (cell cultures) and in vivo (Caenorhabditis elegans, hen’s egg test) approaches for detailed investigation of the impact of commonly used rosemary, citrus and eucalyptus essential oil on acute, developmental and reproductive toxicity as well as on mucous membrane irritation. In general, all EOs under study exhibited a comparable impact on measured parameters, with a slightly increased toxic potential of rosemary oil. In vitro cell culture results indicated a concentration-dependent decrease of cell viability for all EOs, with mean IC₅₀ values ranging from 0.08 to 0.17% [v/v]. Similar results were obtained for the C. elegans model when using a sensitized bus-5 mutant strain, with a mean LC₅₀ value of 0.42% [v/v]. In wild-type nematodes, approximately tenfold higher LC₅₀ values were detected. C. elegans development and reproduction was already significantly inhibited at concentrations of 0.5% (wild-type) and 0.1% (bus-5) [v/v] of EO, respectively. Gene expression analysis revealed a significant upregulation of xenobiotic and oxidative stress genes such as cyp-14a3, gst-4, gpx-6 and sod-3. Furthermore, all three EOs under study showed an increased short-time mucous membrane irritation potential, already at 0.5% [v/v] of EO. Finally, GC–MS analysis was performed to quantitate the relative concentration of the most prominent EO compounds. In conclusion, our results demonstrate that EOs can exhibit severe toxic properties, already at low concentrations. Therefore, a detailed toxicological assessment is highly recommended for each EO and single intended application.

Curcumin, Curcumin Nanoparticles and Curcumin Nanospheres: A Review on Their Pharmacodynamics Based on Monogastric Farm Animal, Poultry and Fish Nutrition

Nanotechnology is an emerging field of science that is widely used in medical sciences. However, it has limited uses in monogastric farm animal as well as fish and poultry nutrition. There are some works that have been done on curcumin and curcumin nanoparticles as pharmaceutics in animal nutrition. However, studies have shown that ingestion of curcumin or curcumin nanoparticles does not benefit the animal health much due to their lower bioavailability, which may result because of low absorption, quick metabolism and speedy elimination of curcumin from the animal body. For these reasons, advanced formulations of curcumin are needed. Curcumin nanospheres is a newly evolved field of nanobiotechnology which may have beneficial effects in terms of growth increment, anti-microbial, anti-inflammatory and neuroprotective effects on animal and fish health by means of nanosphere forms that are biodegradable and biocompatible. Thus, this review aims to highlight the potential application of curcumin, curcumin nanoparticles and curcumin nanospheres in the field of monogastric farm animal, poultry and fish nutrition. We do believe that the review provides the perceptual vision for the future development of curcumin, curcumin nanoparticles and curcumin nanospheres and their applications in monogastric farm animal, poultry and fish nutrition.

Carotenoids: From Plants to Food and Feed Industries

In this review, carotenoids from plants are described, and their natural existence is addressed. Carotenoids are 40-carbon isoprenoid molecules that produce the red, yellow, and orange pigmentation found in nature. Various plants, microalgae, bacteria, and fungi are natural sources of carotenoids and are presented in detail. The chemistry of carotenoids and their classification is also described along with the effect of carotenoids on human health which is explained with focus on lutein-zeaxanthin, astaxanthin, canthaxanthin, capsanthin, and lycopene. Clinical studies suggest that carotenoid consumption is associated with lower risk of cardiovascular disease, cancer, and eye disease. Finally, another issue discussed is the role of carotenoids in animals and their feed with focus on birds, fish and crustaceans, livestock, and poultry.