Weaning pig performance and faecal microbiota with and without in-feed addition of rare earth elements

Maternal Nutrition During Late Gestation and Lactation: Association With Immunity and the Inflammatory Response in the Offspring

The immature immune system at birth and environmental stress increase the risk of infection in nursing pigs. Severe infection subsequently induces intestinal and respiratory diseases and even cause death of pigs. The nutritional and physiological conditions of sows directly affect the growth, development and disease resistance of the fetus and newborn. Many studies have shown that providing sows with nutrients such as functional oligosaccharides, oils, antioxidants, and trace elements could regulate immunity and the inflammatory response of piglets. Here, we reviewed the positive effects of certain nutrients on milk quality, immunoglobulin inflammatory response, oxidative stress, and intestinal microflora of sows, and further discuss the effects of these nutrients on immunity and the inflammatory response in the offspring.

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.

Metagenomic Insights Into the Effects of Rare-Earth Elements Supplementation on Rumen Digestibility and Meat Quality of Beef Cattle

Rare-earth elements (REE), supplemented as feed additives, effectively improved feed conversion and production performances of monogastrics. However, very little information exists on how REE supplementation affects ruminants. In the present study, twenty-four 18-month-old Jinjiang bull cattle, with initial body weight (BW) of 374.75 ± 14.02 kg, were randomly allotted into four dietary treatments with a 15-day-long preliminary trial: a control treatment (basal diet), a 400 mg/kg REE treatment (basal diet supplemented with 400 mg REE/kg DMI), an 800 mg/kg REE treatment (basal diet supplemented with 800 mg REE/kg DMI), and a 1,200 mg/kg REE treatment (basal diet supplemented with 1,200 mg REE/kg DMI). Based on the results, the optimum supplementation scale was chosen for a 60-day-long follow-up feeding procedure. At the end of the feeding period, all bull cattle were slaughtered. Feed intake, average daily weight gain, carcass performances, meat quality, and rumen microbiota were measured. Results indicate a positive response in terms of growth performance and gastrointestinal digestibility to REE supplementation, and 400 mg/kg DMI treatment presented the most average daily feed intake (ADFI), the best average daily weight gain (ADG), and the least F/G. REE also significantly decreased the ruminal propionate content compared with control treatment. As to microbiota, despite no increases in bacterial community abundance, there was a proliferation of Bacteroidetes and Tenericutes and suppression of Actinobacteria under REE treatment. Furthermore, REE treatment significantly increased the meat protein content and decreased meat fat content. There was also an increase in the activities of the enzymes related to lipid syntheses. Fatty acid synthetase (FAS) and malate dehydrogenase (MDH) were significantly suppressed, while the activity of the lipolysis-related enzyme, lipoproteinesterase (LPL), was enhanced. In summary, REE supplementation provided an effective regulation on ruminal microbiota, facilitation of ruminal fiber digestibility, promotion of feed conversion, suppression of lipid deposition, and finally, improved the production and meat quality of beef cattle.

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

There is a need for newer feed additives due to legal prohibition on inclusion of growth promoting antibiotics in livestock diets in several countries due to antimicrobial resistance. In this context, rare earth elements (REE) have gained attention among animal nutritionists as potential growth promoters. Currently, several studies have reported better weight gain, milk production, egg laying capacity and feed conversion efficiency among different breeds of farm animals following supplementation with REE, with however largely inconsistent results. Furthermore, REE supplementation has also shown to improve ruminal fibrolytic and proteolytic activities as well as flavor of meat with negligible residues in edible tissue, however the mechanism behind this action is still unclear. According to existing research, due to their poor absorption and similarity with calcium REE might exert their action locally on gut microbial populations within the gastrointestinal tract (GIT). Moreover, REE have also shown anti-inflammatory, anti-oxidative as well as immune stimulating effects. The present review aims to broaden the knowledge about use of REE as feed additives for livestock and sum up efficacy of REE supplementation on performance and health of animals by comparing the findings. Till date, researches with REE have shown properties that make them a promising, new and safe alternative feed additive but further exploration is recommended to optimize effects and clarify discrepancy of various results before practical proposals can be drafted.

Not merely noxious? Time-dependent hormesis and differential toxic effects systematically induced by rare earth elements in Escherichia coli

Progressive rare earth element (REE) enrichment in aquatic environments worldwide and their resulting anthropogenic anomalies have highlighted the need for a better understanding of their biological effects, with a special emphasis on microbial cells since they play a crucial role in good ecosystem functioning. Therefore, the primary aim of this work was to achieve simultaneous characterization of the 16 REE toxicity effects on the growth kinetics of the commonly found Gram-negative bacterium E. coli (BW25113 strain). Bacterial growth curve modelling showed hormetic effects in the presence of REEs, while EC₅₀ determination (in the mid-log phase) indicated that the four HREEs from Er to Lu in addition to Y were the most toxic metals (EC₅₀ in the range of 8.3 to 3 μM), just after Sc (EC₅₀ of 1.1 μM). Additional subcellular parameter assessment revealed cell membrane lipid peroxidation as well as enhanced membrane depolarization and permeability in the presence of La, Gd, or Yb as representatives of LREEs and HREEs. These subcellular effects appeared to be more intense with Gd and Yb compared with La-exposed cells, in relation to the overall higher toxicity potential reported for HREEs on bacterial growth. Also, the cellular ATP production decreased after REE exposure at their EC₅₀. Finally, these results emphasize the importance of growth kinetic consideration as well as the complexity of REE biological effect mechanisms towards bacteria.

Effects of Maternal Supplementation with Rare Earth Elements during Late Gestation and Lactation on Performances, Health, and Fecal Microbiota of the Sows and Their Offspring

Simple Summary

The immunological and metabolic status of breeding sows directly affect the overall productivity of porcine operations. Especially, maternal health status during the transition from gestation to lactation are important in maintaining health and growth of the suckling piglets. Rare earth elements (REEs) have been considered as a promising natural feed additive and been reported to exert their activity locally within the gastrointestinal tract, including effects on the bacterial microflora and on nutrient utilization. The present study was conducted to explore the effects of dietary maternal REE supplementation during late gestation and lactation on sows and their offspring. After the experiment, we found that maternal REE addition enhanced antioxidant activity and immunity of sows and their suckling piglets. At the same time, REE supplementation during perinatal period improved the reproductivity of the sows as well as the growth of their offspring. Besides, maternal REEs supply altered the intestinal microbiota community and composition of sows as well as their offspring, and Spearman correlation analysis shows that fecal bacteria are associated with the antioxidase, inflammatory factors of the sows and offspring as well as average daily gain of the suckling piglets. In addition, our results suggested that REE supplementation during both gestation and lactation are more beneficial to sows and their offspring than supplementation during only late gestation. This paper holds promise in providing efficient feeding strategies in swine production.

Abstract

The study was conducted to investigate the effects of maternal supplementation with rare earth elements (REEs) on sows and their offspring. During late gestation, 120 multiparous sows were divided randomly into the control group (Basal diet) and REE-G group (Basal diet supplemented with 200 mg REE/kg). After delivery, REE-G group was further divided into two groups: REE-L- (Change to basal diet during lactation) and REE-L+ group (REE diet all the time). Our results showed that maternal REE supplementation improved the antioxidant and immunity of sows and piglets. Additionally, REE supply during late gestation significantly decreased the coefficient of within-litter variation (CV) in birth weight and increased the weaning weights and the average daily gain (ADG) of piglets. During lactation, the insulin-like growth factor-1 (IGF-1) levels in piglets of REE-L+ group were higher, while no difference between REE-L- and the control group. More beneficial bacteria (Christensenellaceae and Ruminococcaceae) were found in the REE-L+ group while some opportunistic pathogens (Proteobacteria and Campylobacter) were relatively suppressed. Fecal microbiota showed correlation with antioxidase, inflammatory factors, and average daily gain (ADG). Collectively, our findings indicated that REEs added in both gestation and lactation was more conducive to establish a healthier status for sows and their offspring.

Impacts of rare earth elements on animal health and production: Highlights of cerium and lanthanum

Because the use of antibiotics as growth promoters was banned due to global health concerns, researchers are focusing on exploring alternative safe and effective feed additives. Rare earth elements (REEs) are located in group III of the periodic table, which includes cerium (Ce), lanthanum (La), and other elements. Recently, REEs have been involved in many medical, industrial, zootechnical, and agricultural applications. They play a pivotal role in functional and structural molecules in the biological system. Currently, in veterinary practice, REEs have been introduced as new feed additives to improve animal health and production. Based on the previous literature, REEs reportedly enhance milk, egg, and meat production. However, the controversy between adverse (e.g., toxicological and ecotoxicological) and favourable REE-associated effects has not been fully discussed. This review summarizes the relevant literature on the impacts of REEs on animal production and health; specifically, this review emphasizes the application of REEs as alternative safe feed additives used to promote animal growth and performance.

Human exposures to rare earth elements: Present knowledge and research prospects

The extensive use of rare earth elements (REEs) in a number of technologies is expected to impact on human health, including occupational and environmental REE exposures. A body of experimental evidence on REE-associated toxicity has been accumulated in recent decades, thus providing extensive background information on the adverse effects of REE exposures. Unlike experimental studies, the consequences of REE exposures to human health have been subjected to relatively fewer investigations. Geographical studies have been conducted on residents in REE mining districts, reporting on REE bioaccumulation, and associations between REE residential exposures and adverse health effects. A recent line of studies has associated tobacco smoking and indoor smoke with increased levels of some REEs in exposed residents. A body of literature has been focused on occupational REE exposures, with the observation of respiratory tract damage. The occupations related to REE mining and processing have shown REE bioaccumulation in scalp hair, excess REE urine levels, and defective gene expression. As for other REE occupational exposures, mention should be made of: a) jobs exposing to REE aerosol, such as movie operator; b) e-waste processing and, c) diesel engine repair and maintenance, with exposures to exhaust microparticulate (containing nanoCeO₂ as a catalytic additive). Diesel exhaust microparticulate has been studied in animal models, leading to evidence of several pathological effects in animals exposed by respiratory or systemic routes. A working hypothesis for REE occupational exposures is raised on REE-based supermagnet production and manufacture, by reviewing experimental studies that suggest several pathological effects of static magnetic fields, and warrant further investigations.

Impact of rare earth element-enriched yeast on growth performance, nutrient digestibility, blood profile, and fecal microflora in finishing pigs

This study was conducted to evaluate effects of rare earth element-enriched yeast (RY) on growth performance, nutrient digestibility, blood profile, and fecal microbial flora in finishing pigs. A total of 100 finishing pigs [(Landrace × Yorkshire) × Duroc] were used in a two-phase feeding trial. Pigs were randomly assigned to five treatments according to their initial body weight (five pens per treatment, two gilts and two barrows per pen). Treatments were basal diets, free of antibiotics [negative control (NC)]; NC + 500, 1000, and 1500 mg kg−1, respectively, of RY; antibiotics diets, NC + 500 mg kg−1 of tiamulin [positive control (PC)]. Overall, average daily gain (ADG) and gain to feed ratio (G:F) increased linearly with increasing level of RY in diets. At the end of the experiment, blood lymphocyte concentration and apparent total tract digestibility of dry matter and gross energy increased linearly in pigs fed the increasing level of RY in diets. The better ADG, G:F, and fecal Lactobacillus counts were observed in both RY and PC groups compared with the NC group. In conclusion, diets with RY improved growth performance, digestibility, blood lymphocyte counts, and fecal Lactobacillus counts in finishing pigs, and RY may be considered as an alternative to antibiotics.

Dietary High Fluorine Alters Intestinal Microbiota in Broiler Chickens

This study investigated the effects of dietary high fluorine on ileal and cecal microbiota in broiler chickens. Two hundred eighty 1-day-old broiler chickens were randomly assigned to four groups and raised for 42 days. The control group was fed a corn-soybean basal diet (fluorine 22.6 mg/kg). The other three groups were fed the same basal diet, but supplemented with 400, 800, and 1200 mg/kg fluorine (high fluorine groups I, II, and III), administered in the form of sodium fluoride. The microbiota of ileal and cecal digesta was assessed with plate counts and polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE). It was found that, compared with those in the control group, the counts of Lactobacillus spp. and Bifidobacterium spp. were markedly decreased (P < 0.01 or P < 0.05), whereas the counts of Escherichia coli and Enterococcus spp. were significantly increased (P < 0.01 or P < 0.05) in the high fluorine groups II and III. PCR-DGGE analysis showed that the number of DGGE bands, similarity, and Shannon index of ileal and cecal bacteria were markedly reduced in the high fluorine groups II and III from 21 to 42 days. Sequencing analysis revealed that the composition of the intestinal microbiota was altered in the high fluorine groups. In conclusion, dietary fluorine in the range of 800-1200 mg/kg obviously altered the bacterial counts, and the diversity and composition of intestinal microbiota in broiler chickens, a finding which implies that dietary high fluorine can disrupt the natural balance and structure of the intestinal microbiota.

Rare earth elements in human and animal health: State of art and research priorities

BACKGROUND

A number of applications have been developed using rare earth elements (REE), implying several human exposures and raising unsolved questions as to REE-associated health effects.

METHODS

A MedLine survey was retrieved from early reports (1980s) up to June 2015, focused on human and animal exposures to REE. Literature from animal models was selected focusing on REE-associated health effects.

RESULTS

Some REE occupational exposures, in jobs such as glass polishers, photoengravers and movie projectionists showed a few case reports on health effects affecting the respiratory system. No case-control or cohort studies of occupational REE exposures were retrieved. Environmental exposures have been biomonitored in populations residing in REE mining areas, showing REE accumulation. The case for a iatrogenic REE exposure was raised by the use of gadolinium-based contrast agents for nuclear magnetic resonance. Animal toxicity studies have shown REE toxicity, affecting a number of endpoints in liver, lungs and blood. On the other hand, the use of REE as feed additives in livestock is referred as a safe and promising device in zootechnical activities, possibly suggesting a hormetic effect both known for REE and for other xenobiotics. Thus, investigations on long-term exposures and observations are warranted.

CONCLUSION

The state of art provides a limited definition of the health effects in occupationally or environmentally REE-exposed human populations. Research priorities should be addressed to case-control or cohort studies of REE-exposed humans and to life-long animal experiments.

Toxicological effects of dietary nickel chloride on intestinal microbiota

This study was designed to evaluate the toxicological effect of dietary nickel chloride (NiCl2) on the counts of intestinal bacteria and diversity of microorganisms in broilers. Plate counting and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) assays were used. A total of 240 one-day-old avian broilers chicks were divided into four equal groups and kept on corn-soybean basal diet along with supplementation of 0, 300, 600 and 900 mg/kg NiCl2 for 42 days. Samples were taken at 21 and 42 days of age during the experiment. The bacterial count results showed that dietary NiCl2 in the range of 300 to 900 mg/kg decreased the counts of Bifidobacterium spp. and Lactobacillus, increased Escherichia coli (E. coli) and Enterococcus spp. in the ileum and cecum. PCR-DGGE analysis showed that bacterial band numbers, profile similarity, and the Shannon index of the ileum and cecum were all decreased in the 300, 600, and 900 mg/kg groups at 21 and 42 days of age. In conclusion, dietary NiCl2 affected the amount and diversity of intestinal microbiota in the ileum and cecum of broilers. This finding implies that NiCl2 has toxicological effect on the intestinal ecosystem and, possibly functions.

Alternatives to antibiotics as growth promoters for use in swine production: a review

In the past two decades, an intensive amount of research has been focused on the development of alternatives to antibiotics to maintain swine health and performance. The most widely researched alternatives include probiotics, prebiotics, acidifiers, plant extracts and neutraceuticals such as copper and zinc. Since these additives have been more than adequately covered in previous reviews, the focus of this review will be on less traditional alternatives. The potential of antimicrobial peptides, clay minerals, egg yolk antibodies, essential oils, eucalyptus oil-medium chain fatty acids, rare earth elements and recombinant enzymes are discussed. Based on a thorough review of the literature, it is evident that a long and growing list of compounds exist which have been tested for their ability to replace antibiotics as feed additives in diets fed to swine. Unfortunately, the vast majority of these compounds produce inconsistent results and rarely equal antibiotics in their effectiveness. Therefore, it would appear that research is still needed in this area and that the perfect alternative to antibiotics does not yet exist.

Dietary inclusion of feathers affects intestinal microbiota and microbial metabolites in growing Leghorn-type chickens

Feather pecking in laying hens is a serious behavioral problem that is often associated with feather eating. The intake of feathers may influence the gut microbiota and its metabolism. The aim of this study was to determine the effect of 2 different diets, with or without 5% ground feathers, on the gut microbiota and the resulting microbial fermentation products and to identify keratin-degrading bacteria in chicken digesta. One-day-old Lohmann-Selected Leghorn chicks were divided into 3 feeding groups: group A (control), B (5% ground feathers in the diet), and C, in which the control diet was fed until wk 12 and then switched to the 5% feather diet to study the effect of time of first feather ingestion. The gut microbiota was analyzed by cultivation and denaturing gradient gel electrophoresis of ileum and cecum digesta. Short-chain fatty acids, ammonia, and lactate concentrations were measured as microbial metabolites. The concentration of keratinolytic bacteria increased after feather ingestion in the ileum (P < 0.001) and cecum (P = 0.033). Bacterial species that hydrolyzed keratin were identified as Enterococcus faecium, Lactobacillus crispatus, Lactobacillus reuteri-like species (97% sequence homology), and Lactobacillus salivarius-like species (97% sequence homology). Molecular analysis of cecal DNA extracts showed that the feather diet lowered the bacterial diversity indicated by a reduced richness (P < 0.001) and shannon (P = 0.012) index. The pattern of microbial metabolites indicated some changes, especially in the cecum. This study showed that feather intake induced an adaptation of the intestinal microbiota in chickens. It remains unclear to what extent the changed metabolism of the microbiota reflects the feather intake and could have an effect on the behavior of the hens.

Dose-dependent effects of dietary zinc oxide on bacterial communities and metabolic profiles in the ileum of weaned pigs

Pharmacological levels of zinc oxide (ZnO) can improve the health of weaning piglets and influence the intestinal microbiota. This experiment aimed at studying the dose-response effect of five dietary concentrations of ZnO on small intestinal bacteria and metabolite profiles. Fifteen piglets, weaned at 25 ± 1 days of age, were allocated into five groups according to body weight and litter. Diets were formulated to contain 50 (basal diet), 150, 250, 1000 and 2500 mg zinc/kg by adding analytical-grade (>98% purity) ZnO to the basal diet and fed ad libitum for 14 days after a 7-day adaptation period on the basal diet. Ileal bacterial community profiles were analysed by denaturing gradient gel electrophoresis and selected bacterial groups quantified by real-time PCR. Concentrations of ileal volatile fatty acids (VFA), D- and L-lactate and ammonia were determined. Species richness, Shannon diversity and evenness were significantly higher at high ZnO levels. Quantitative PCR revealed lowest total bacterial counts in the 50 mg/kg group. Increasing ZnO levels led to an increase (p = 0.017) in enterobacteria from log 4.0 cfu/g digesta (50 mg/kg) to log 6.7 cfu/g digesta (2500 mg/kg). Lactic acid bacteria were not influenced (p = 0.687) and clostridial cluster XIVa declined (p = 0.035) at highest ZnO level. Concentration of total, D- and L-lactate and propionate was not affected (p = 0.736, p = 0.290 and p = 0.630), but concentrations of ileal total VFA, acetate and butyrate increased markedly from 50 to 150 mg/kg and decreased with further increasing zinc levels and reached low levels again at 2500 mg/kg (p = 0.048, p = 0.048 and p = 0.097). Ammonia decreased (p < 0.006) with increasing dietary ZnO level. In conclusion, increasing levels of dietary ZnO had strong and dose-dependent effects on ileal bacterial community composition and activity, suggesting taxonomic variation in metabolic response to ZnO.

Genetic identification of mammalian carnivore species in the Kushiro Wetland, eastern Hokkaido, Japan, by analysis of fecal DNA

To identify mammalian carnivore species distributed in the Kushiro Wetland, eastern Hokkaido, Japan, we developed molecular-genetic methods for identification of the species from fecal samples collected from the field. Species-specific primers and PCR programs were established for five native and six alien species of carnivores: Martes zibellina, Mustela nivalis, Mustela erminea, Vulpes vulpes, and Nyctereutes procyonoides as native species, and Neovison vison, Martes melampus, Mustela itatsi, Canis familiaris, Felis catus, and Procyon lotor as alien species in Hokkaido. Touchdown PCR, in which the annealing temperature is decreased 1 degrees C every cycle, was more effective for some species from which fecal DNA was not amplified species-specifically with standard PCR programs. Of 405 fecal samples collected from the Kushiro Wetland, the species of origin of 246 samples were successfully identified: 88 samples for N. vison, 140 for M. zibellina, 13 for V. vulpes, four for C. familiaris and one for F. catus. The results show the particular applicability of this method to monitoring M. zibellina and N. vison. In addition, methods to PCR-amplify DNA from two crayfish species (Pacifastacus leniusculus and Cambaroides japonicus) were developed to determine whether the carnivore fecal samples contained detectable DNA from the prey crayfishes. DNA from P. leniusculus was amplified from feces of N. vison identified in the present study, but no DNA from C. japonicus was detected. This indicates that N. vison preys on the alien species P. leniusculus.

Effects of dietary inulin on the intestinal short chain fatty acids and microbial ecology in broiler chickens as revealed by denaturing gradient gel electrophoresis

Inulin can stimulate the growth of the intestinal bacteria as well as alter the ratio among various short chain fatty acids (SCFA) produced. In the present study, we analyzed the effect of dietary inulin on the intestinal bacterial community as determined by denaturing gradient gel electrophoresis analysis of universal 16S rDNA after amplication with PCR and SCFA profile. Broilers were fed a diet primarily composed of corn-soybean meal or same diet with 1% inulin for 42 d. The relative weight of digesta-filled ceca of the inulin-fed group was higher (P<0.01) than in the control group. Amongst SCFA, only acetate could be detected in the jejunal digesta, which tended to be higher (P=0.09) in inulin-fed group compared with the control group. Inulin did not affect the total concentration of SCFA in the cecal digesta. The relative proportion of n-butyrate was elevated (P=0.05) with a concomitant decrease in the concentration of n-valerate (P<0.05) in the inulin-fed group compared with the control group. Dietary inulin did not affect the number of PCR-denaturing gradient gel electrophoresis bands nor their diversity in the jejunal and cecal digesta. Intragroup similarities were not different between the groups, nor were any differences between intra-and intergroup similarities in the jejunal and cecal samples. In conclusion, inulin altered the cecal microbial metabolic activity without any major impact on the composition of intestinal bacterial communities as measured by the present techniques.