Perspectives for rare earth elements as feed additive in livestock - A review

Mercury and rare earth elements (REEs) show different spatial trends in feathers of Kentish plover (Charadrius alexandrinus) breeding along the Adriatic Sea coast, Italy

Feather analysis is an ethical and effective method for assessing the exposure of wild birds to environmental contamination due to trace elements and organic pollutants. We used feather to monitor the exposure to three toxic and non-essential metals (Hg, Cd, and Pb) and rare earth elements (REEs) of Kentish plover (Charadrius alexandrinus) breeding in different coastal areas (Veneto, Emilia-Romagna, Marche, Abruzzo, and Apulia) along the Italian coast of the Adriatic Sea. Feathers (n = 113) were collected from April to June. Feather concentrations evidenced a significant exposure to Hg (13.05 ± 1.71 mg kg-1 dw) and REEs (447.3 ± 52.8 ng g-1 dw) in the Kentish plover breeding in Veneto (n = 21) compared to the other coastal areas, with several individuals showing Hg concentrations above the adverse effect (5 mg kg-1 dw) and high-risk (9.14 mg kg-1 dw) thresholds reported for birds. Higher REE concentrations compared to Marche (n = 29), Abruzzo (n = 11) and Apulia (n = 13) were also reported for birds breeding in Emilia-Romagna (474.9 ± 41.9 ng g-1 dw; n = 29). The exposure to Cd and Pb was low in all the coastal areas, and only a few samples (n = 6 and n = 4 for Cd and Pb, respectively) exceeded the adverse effect thresholds (0.1 and 4 mg kg-1 for Cd and Pb, respectively). A significant sex-related difference was observed for REE-concentrations, with females showing higher concentration than males. These data highlight the need to monitor the exposure of the Kentish plover to Hg and REEs, especially in the northern basin of the Adriatic Sea, since these elements might negatively affect species' reproductive success and threaten its conservation.

Rare earth contamination of edible vegetation: Ce, La, and summed REE in fungi

The increasing and diversified use of rare earth elements (REE) is considered a potential source of pollution of environmental media including soils. This work documents critically overview data on the occurrence of REE in the fruiting bodies of wild and farmed species of edible and medicinal mushrooms, as this was identified as the largest published dataset of REE occurrence in foodstuff. Most of the literature reported occurrences of cerium (Ce) and lanthanum (La), but a number of studies lacked data on all lanthanides. The Ce, La, and summed REE occurrences were assessed through the criteria of environmental geochemistry, analytical chemistry, food toxicology, mushroom systematics, and ecology. Ce and La accumulate similarly in fruiting bodies and are not fractionated during uptake, maintaining the occurrence patterns of their growing substrates. Similarly, there is no credible evidence of variable REE uptake because the evaluated species data show natural, unfractionated patterns in accordance with the Oddo-Harkins' order of environmental lanthanide occurrence. Thus, lithosphere occurrence patterns of Ce and La as the first and the third most abundant lanthanides are reflected in wild and farmed mushrooms regardless of substrate and show that Ce is around twice more abundant than La. The current state of knowledge provides no evidence that mushroom consumption at these REE occurrence levels poses a health risk either by themselves or when included with other dietary exposure. Macromycetes appear to bio-exclude lanthanides because independently reported bioconcentration factors for different species and collection sites, typically range from < 1 to 0.001. This is reflected in fruiting body concentrations which are four to two orders of magnitude lower than growing substrates. KEY POINTS: •Original REE occurrence patterns in soils/substrates are reflected in mushrooms •No evidence for the fractionation of REE during uptake by fungi •Mushrooms bio-exclude REE in fruiting bodies.

Effects of Dietary Supplementation with Caesalpinia sappan Linn. Extract for Promoting Flock Health and Performance in Late-Phase Laying Hens

The present study investigated the effects of dietary supplementation of Caesalpinia sappan Linn Extract (CSE) on the health and productive performance of late-phase laying hens on farms. Proximate composition and antioxidant markers of CSE powder revealed favorable characteristics with high total dry matter; phenolic content, and antioxidant potency. Three hundred and sixty (64-week-old) Hy-line Brown hens were divided into five groups with 0 (control diet), 250, 500, 1000, and 2000 mg/kg CSE, respectively. The laying performance and egg quality of the CSE supplementation groups demonstrated significant improvements in egg weight and albumin weight (p < 0.05), and a tendency for enhanced egg mass and feed conversion ratio. Additionally, the intestinal morphostructural indices in the 2000 mg CSE/kg diet group showed the greatest statistical significance (p < 0.05), with a detectable trend suggesting an increase in the villus height to crypt depth ratio. In addition, significant downregulation of proinflammatory genes occurred in their liver tissues, coupled with a greater expression of genes linked to antioxidants and anti-inflammatory processes. Furthermore, the blood biochemical parameters and the organ weights may suggest a favorable safety profile of CSE supplementation. These findings highlight the potential of CSE as a dietary supplement to enhance the productive performance and flock health of late-phase laying hens. Further research is warranted to explore the long-term effects and optimal dosage of CSE supplementation for laying hens in farming practices.

Rare Earths-The Answer to Everything

Rare earths, scandium, yttrium, and the fifteen lanthanoids from lanthanum to lutetium, are classified as critical metals because of their ubiquity in daily life. They are present in magnets in cars, especially electric cars; green electricity generating systems and computers; in steel manufacturing; in glass and light emission materials especially for safety lighting and lasers; in exhaust emission catalysts and supports; catalysts in artificial rubber production; in agriculture and animal husbandry; in health and especially cancer diagnosis and treatment; and in a variety of materials and electronic products essential to modern living. They have the potential to replace toxic chromates for corrosion inhibition, in magnetic refrigeration, a variety of new materials, and their role in agriculture may expand. This review examines their role in sustainability, the environment, recycling, corrosion inhibition, crop production, animal feedstocks, catalysis, health, and materials, as well as considering future uses.

Evaluation of Rare Earth Element-Associated Hormetic Effects in Candidate Fertilizers and Livestock Feed Additives

Rare earth elements (REEs) are recognized as emerging contaminants with implications in human and environmental health. Apart from their adverse effects, REEs have been reported as having positive effects when amended to fertilizers and livestock feed additives, thus suggesting a hormetic trend, implying a concentration-related shift from stimulation to inhibition and toxicity, with analogous trends that have been assessed for a number of xenobiotics. In view of optimizing the success of REE mixtures in stimulating crop yield and/or livestock growth or egg production, one should foresee the comparative concentration-related effects of individual REEs (e.g., Ce and La) vs. their mixtures, which may display distinct trends. The results might prompt further explorations on the use of REE mixtures vs. single REEs aimed at optimizing the preparation of fertilizers and feed additives, in view of the potential recognition of their use in agronomy and zootechny.

Evaluation of a dacitic (rhyolitic) tuff breccia use on performance, inflammatory, and antioxidant responses in broilers mildly challenged with Eimeria spp

The objective of the study was to investigate the effects of a dacitic tuff breccia (DTB) on Eimeria-infected broilers. A total of 600 one-day-old Cobb 500 male chickens were randomly assigned to 5 treatments with 10 replicates of 12 birds. Treatments were: an unchallenged control (UC), a challenged (CC) control (0% DTB), and 3 challenged groups with 0.125, 0.25, or 0.5% DTB. At d 14, birds in the CC and DTB groups were orally gavaged with mixed Eimeria spp., while the UC received water. Growth performance was evaluated during prechallenge, challenge, and postchallenge periods (0-14 d; 14-20 d; and 20-26 d, respectively). Gastrointestinal permeability was measured at 5 days postinfection (dpi). Intestinal histology and nutrient digestibility of dry matter (DM), crude protein (CP), and ileal digestible energy (IDE) were measured at 6 dpi. Liver activity of glutathione peroxidase (GSH-Px) was determined at 6 dpi, and concentrations of reduced (GSH) and oxidized glutathione (GSSG) were analyzed at 6 and 12 dpi. Data were analyzed using a linear mixed model analysis and Tukey's test (P ≤ 0.05). From 0 to 14 d, similar average daily gain (ADG) and average daily feed intake (ADFI, P > 0.05) were observed. Gain:feed ratio (GF) was higher in 0.125, 0.25, and 0.5% of DTB than the CC and UC (P < 0.001). From 14 to 20 d, the UC had the highest ADG, ADFI, and GF (P < 0.001). At 5 dpi, intestinal permeability was higher in the challenged groups than the UC. Additionally, the UC showed the highest apparent ileal digestibility of CP, whereas 0.125% DTB had higher CP digestibility than the CC and 0.5% DTB (P < 0.001). At 6 dpi, 0.125% DTB increased GSH-Px activity compared to the CC, 0.5% DTB, and UC (P < 0.001). At 12 dpi, 0.125% DTB showed increased GSH concentration compared to the CC, 0.25% DTB, and 0.5% DTB (P < 0.01). The mild coccidia infection negatively impacted growth performance, apparent ileal nutrient digestibility, intestinal histology, and gastrointestinal integrity in broilers. The use of 0.125% DTB exhibited potential in improving antioxidant responses, apparent ileal digestibility of CP, and growth performance.

Effects of Dietary Rare Earth Chitosan Chelate on Performance, Egg Quality, Immune and Antioxidant Capacity, and Intestinal Digestive Enzyme Activity of Laying Hens

Rare earth chitosan chelate salt (RECC) is a potential feed additive and is a product of the chelation effect between rare earth ions and chitosan. This research study aims to explore the effects of dietary RECC on performance, egg quality, intestinal digestive function, and the immune and antioxidant capacity of laying hens in the late phase of production. A total of 360 56-week-old Dawu Jinfeng laying hens were randomly allotted into four treatment groups with six replicates per treatment and 15 birds per replicate. The laying hens were fed the basal diet supplemented with, respectively, 0 (control: CON), 100 (R1), 200 (R2), and 400 (R3) mg/kg for 8 weeks. Dietary RECC significantly improved average daily feed intake (ADFI) and average daily egg yield in both linear and quadratic manner (p < 0.05). In addition, albumen height and HU were improved significantly (p < 0.05) in a dose-dependent manner of RECC. In addition, a significant decrease (p < 0.05) in serum TP, IgA, and MDA for the R1 group and IgG in the R2 group were notable, while the increase in serum TP and decrease in T-AOC were found for R3 dietary group compared to CON (p < 0.05). The level of intestinal IL-2 and TNF-α was decreased by dietary RECC (p < 0.01). The activities of the digestive enzyme (α-Amylase, lipase, and Trypsin) showed a quadratic change with an increase and then decrease in response to increasing dose of RECC, 200 mg/kg RECC significantly increased the activity of lipase and Trypsin (p < 0.01). Supplementation of dietary RECC at low doses compared to higher doses impacted positive effects on the antioxidant capacity and immune function (p < 0.05). The utilization of RECC as a feed additive in the diet of aged laying hens exerted beneficial effects on egg production, albumen quality, humoral immunity, inflammatory response, and activity of digestive enzymes. Thus, the regulation of antioxidant capacity and duodenal function via increased enzyme activity and immune and inflammatory response were critical to the improvement of laying performance and egg quality in aged hens. The optimal supplemental dose is 100-200 mg/kg.

Review of Rare Earth Elements as Fertilizers and Feed Additives: A Knowledge Gap Analysis

Rare earth elements (REEs) are key constituents of modern technology and play important roles in various chemical and industrial applications. They also are increasingly used in agricultural and zootechnical applications, such as fertilizers and feed additives. Early applications of REEs in agriculture have originated in China over the past several decades with the objective of increasing crop productivity and improving livestock yield (e.g., egg production or piglet growth). Outside China, REE agricultural or zootechnical uses are not currently practiced. A number of peer-reviewed manuscripts have evaluated the adverse and the positive effects of some light REEs (lanthanum and cerium salts) or REE mixtures both in plant growth and in livestock yield. This information was never systematically evaluated from the growing body of scientific literature. The present review was designed to evaluate the available evidence for adverse and/or positive effects of REE exposures in plant and animal biota and the cellular/molecular evidence for the REE-associated effects. The overall information points to shifts from toxic to favorable effects in plant systems at lower REE concentrations (possibly suggesting hormesis). The available evidence for REE use as feed additives may suggest positive outcomes at certain doses but requires further investigations before extending this use for zootechnical purposes.

Dietary inclusion of AZOMITE improves feed efficiency in broilers and egg production in laying and broiler breeder hens

The dietary inclusion of aluminosilicates has been reported to enhance pellet quality, improve feed mill throughput, bind toxins, improve feed efficiency, and promote immunological function across a variety of production systems. AZOMITE is a product marketed as a hydrated sodium calcium aluminosilicate containing macro and trace minerals, and rare earth elements and the potential benefits of its dietary inclusion in broiler, layer, and broiler breeder diets was investigated. In a battery study, broilers were fed diets containing 0, 0.125, 0.250, or 0.500% AZOMITE from 0 to 21 d of age. Laying hens were fed a control diet or this diet supplemented with 0.25% AZOMITE from 54 through 98 wk of age, with the hens fed a standard molting diet or this diet supplemented with 0.25% AZOMITE from 71 to 72 wk of age. Broiler breeder hens were fed a control diet or this diet supplemented with 0.25% AZOMITE from the onset of photostimulation at 21 wk of age through 65 wk of age. All 3 dietary inclusion rates of AZOMITE improved (P < 0.05) the feed to body weight gain ratio in broilers fed these diets relative to broilers fed the control diet. In laying hens total marketable eggs, and in broiler breeder hens total settable eggs were increased (P < 0.05) with the dietary inclusion of AZOMITE by 8 eggs per hen. The inclusion of dietary AZOMITE also improved apparent Ca and P digestibility in broilers and tibia ash content in laying hens. The results indicate the dietary inclusion of AZOMITE in poultry diets improves bird performance.

Excessive dietary lead reduces growth performance and increases lead accumulation in pigs

Objective: The objective of this study was to investigate the influence of dietary lead (Pb) supplementation and feeding period on growth performance, organ weight, and Pb accumulation in pigs.Methods: In a 56-day feeding experiment, a total of 48 barrows with initial body weight 10.4±0.6 kg were allotted to 2 dietary treatments (0 and 200 mg/kg of supplemental Pb) in a completely randomized design with 6 replicates. Body weight and feed intake were recorded to calculate growth performance. At the end of each 14 day-period (on days 14, 28, 42, and 56), an animal was randomly selected from each pen and slaughtered to collect blood samples, hair samples, left 5th rib, heart, liver, kidneys, lungs, and longissimus dorsi muscle samples.Results: Average daily gain and average daily feed intake were reduced (p<0.05) by supplemental Pb during the day 42 to 56. Relative kidney weight to body weight was linearly increased with increasing feeding period in pigs fed the Pb-supplemented diet, but not in pigs fed the control diet (p<0.05). The Pb concentrations in hair, left 5th rib, kidneys, and lungs were linearly increased with longer feeding period in pigs fed the Pb-supplemented diet, but not in pigs fed the control diet (p<0.01).Conclusion: Dietary Pb supplementation caused growth retardation and Pb accumulation in most organs, particularly in hair, bone, and kidneys in a time-dependent manner.