Effects of 5-aminolevulinic acid supplementation on milk production, iron status, and immune response of dairy cows

Gene expression regulation by modulating Hfq expression in coordination with tailor-made sRNA-based knockdown in Escherichia coli

The tailor-made synthetic sRNA-based gene expression knockdown system has demonstrated its efficacy in achieving pathway balancing in microbes, facilitating precise target gene repression and fine-tuned control of gene expression. This system operates under a competitive mode of gene regulation, wherein the tailor-made synthetic sRNA shares the intrinsic intracellular Hfq protein with other RNAs. The limited intracellular Hfq amount has the potential to become a constraining factor in the post-transcription regulation of sRNAs. To enhance the efficiency of the tailor-made sRNA gene expression regulation platform, we introduced an Hfq expression level modulation-coordinated sRNA-based gene knockdown system. This system comprises tailor-made sRNA expression cassettes that produce varying Hfq expression levels using different strength promoters. Modulating the expression levels of Hfq significantly improved the repressing capacity of sRNA, as evidenced by evaluations with four fluorescence proteins. In order to validate the practical application of this system, we applied the Hfq-modulated sRNA-based gene knockdown cassette to Escherichia coli strains producing 5-aminolevulinic acid and L-tyrosine. Diversifying the expression levels of metabolic enzymes through this cassette resulted in substantial increases of 74.6% in 5-aminolevulinic acid and 144% in L-tyrosine production. Tailor-made synthetic sRNA-based gene expression knockdown system, coupled with Hfq copy modulation, exhibits potential for optimizing metabolic fluxes through biosynthetic pathways, thereby enhancing the production yields of bioproducts.

Enhancing Milk Production by Nutrient Supplements: Strategies and Regulatory Pathways

The enhancement of milk production is essential for dairy animals, and nutrient supplements can enhance milk production. This work summarizes the influence of nutrient supplements-including amino acids, peptides, lipids, carbohydrates, and other chemicals (such as phenolic compounds, prolactin, estrogen and growth factors)-on milk production. We also attempt to provide possible illuminating insights into the subsequent effects of nutrient supplements on milk synthesis. This work may help understand the strategy and the regulatory pathway of milk production promotion. Specifically, we summarize the roles and related pathways of nutrients in promoting milk protein and fat synthesis. We hope this review will help people understand the relationship between nutritional supplementation and milk production.

Reduction of oocyte shedding and cecal inflammation by 5-aminolevulinic acid daily supplementation in laying hens infected with Eimeria tenella

The present study aimed to evaluate the effects of 5-aminolevulinic acid (5-ALA) on Eimeria tenella infection in laying hens. Oocyst shedding and histopathology were evaluated. A reduced oocyst shedding was observed 5 and 7 days post-infection (dpi) in the 5-ALA-administered group, but the total number of oocysts during the first infection period was not different between control and 5-ALA-treated groups. After E. tenella attack infection, the period of oocyst shedding in the 5-ALA-administered group lasted less long than that in controls. During the attack infection period, the total number of fecal oocysts in the 5-ALA-treated group was significantly lower than that in the control group. However, the parasite burden score in hens receiving 5-ALA was higher than that in controls after E. tenella attack infection. The lesion scores at 5 and 30 dpi in the control group were significantly lower than those in the 5-ALA-administered group. Therefore, 5-ALA administration might be beneficial against E. tenella infection in laying hens.

Effects of Feeding 5-Aminolevulinic Acid on Iron Status in Weaned Rats from the Female Rats during Gestation and Lactation

Using female Sprague−Dawley (SD) rats as a model, the current study aimed to investigate whether feeding 5-aminolevulinic acid (5-ALA) to female SD rats during gestation and lactation can affect the iron status of weaned rats and provide new ideas for the iron supplementation of piglets. A total of 27 pregnant SD rats were randomly assigned to three treatments in nine replicates, with one rat per litter. Dietary treatments were basal diet (CON), CON + 50 mg/kg 5-ALA (5-ALA50), and CON + 100 mg/kg 5-ALA (5-ALA100). After parturition, ten pups in each litter (a total of 270) were selected for continued feeding by their corresponding mother, and the pregnant rats were fed diets containing 5-ALA (0, 50 and 100 mg/kg diet) until the newborn pups were weaned at 21 days. The results showed that the number of red blood cells (RBCs) in weaned rats in the 5-ALA100 group was significantly higher (p < 0.05) than that in the CON or 5-ALA50 group. The diet with 5-ALA significantly increased (p < 0.05) the hemoglobin (HGB) concentration, hematocrit (HCT) level, serum iron (SI) content, and transferrin saturation (TSAT) level in the blood of weaned rats, as well as the concentration of Hepcidin in the liver and serum of weaned rats and the expression of Hepcidin mRNA in the liver of weaned rats, with the 5-ALA100 group having the highest (p < 0.05) HGB concentration in the weaned rats, and the 5-ALA50 group having the highest (p < 0.05) Hepcidin concentration in serum and in the expression of Hepcidin mRNA in the liver of weaned rats. The other indicators between the 5-ALA groups had no effects. However, the level of total iron binding capacity (TIBC) was significantly decreased (p < 0.05) in the 5-ALA50 group. Moreover, the iron content in the liver of weaned rats fed with 5-ALA showed an upward trend (p = 0.085). In addition, feeding a 5-ALA-supplemented diet could also significantly reduce (p < 0.05) the expression of TfR1 mRNA in the liver of weaning rats (p < 0.05), and the expression of Tfr1 was not affected between 5-ALA groups. In conclusion, dietary supplementation with 5-ALA could improve the blood parameters, increase the concentration of Hepcidin in the liver and serum, and affect the expression of iron-related genes in the liver of weaned rats. Moreover, it is appropriate to add 50 mg/kg 5-ALA to the diet under this condition.

Protective effects of 5-aminolevulinic acid against toxicity induced by alpha-cypermethrin to the liver-gut-microbiota axis in zebrafish

To explore whether and how 5-aminolevulinic acid (ALA) can relieve the toxicity to the liver-gut-microbiota axis caused by alpha-cypermethrin (α-CP), adult zebrafish were exposed to α-CP (1.0 µg L-1) with or without 5.0 mg L-1 ALA supplementation. In the present work, the calculated LC50 of α-CP+ALA was 1.15 μg L-1, increasing about 1.16-fold compared with that of α-CP group (0.99 μg L-1), which indicated that ALA can alleviate the toxicity of α-CP. ALA also alleviated the histopathological lesions in the liver and gut induced by α-CP. Transcriptome sequencing of the liver showed that ALA rescues the differential expression of genes involved in the oxidation-reduction, heme metabolism, and complement activation pathways associated with dysfunctions induced by α-CP, and these findings were verified by RT-qPCR analysis and detection of the activities of enzymes in the liver-gut axis. The gut microbiota 16S rRNA sequencing results showed that α-CP alone induced gut microbial dysbiosis, which was efficiently antagonized by ALA due to decreasing the relative abundances of Cetobacterium and 3 major pathogens, and increasing the relative abundances of beneficial genera. Taken together, the results indicate that ALA might be a promising candidate for attenuating the adverse effects caused by pesticide-induced environmental pollution.

Metabolic profiling of serum and urine in lactating dairy cows affected by subclinical ketosis using proton nuclear magnetic resonance spectroscopy

Ketosis is associated with high milk yield during lactating or insufficient feed intake in lactating dairy cows. However, few studies have been conducted on the metabolomics of ketosis in Korean lactating dairy cows. The present study aimed to investigate the serum and urine metabolites profiling of lactating dairy cows through proton nuclear magnetic resonance (¹H-NMR) spectroscopy and comparing those between healthy (CON) and subclinical ketosis (SCK) groups. Six lactating dairy cows were categorized into CON and SCK groups. All experimental Holstein cows were fed total mixed ration. Serum and urine samples were collected from the jugular vein of the neck and by hand sweeping the perineum, respectively. The metabolites in the serum and urine were determined using ¹H-NMR spectroscopy. Identification and quantification of metabolites was performed by Chenomx NMR Suite 8.4 software. Metabolites statistical analysis was performed by Metaboanalyst version 5.0 program. In the serum, the acetoacetate level was significantly (p < 0.05) higher in the SCK group than in the CON group, and whereas acetate, galactose and pyruvate levels tended to be higher. CON group had significantly (p < 0.05) higher levels of 5-aminolevulinate and betaine. Indole-3-acetate, theophylline, p-cresol, 3-hydroxymandelate, gentisate, N-acetylglucosamine, N-nitrosodimethylamine, xanthine and pyridoxine levels were significantly (p < 0.05) higher in the urine of the SCK group than that in the CON group, which had higher levels of homogentisate, ribose, gluconate, ethylene glycol, maltose, 3-methyl-2-oxovalerate and glycocholate. Some significantly (p < 0.05) different metabolites in the serum and urine were associated with ketosis diseases, inflammation, energy balance and body weight. This study will be contributed useful a future ketosis metabolomics studies in Korea.

Natural 5-Aminolevulinic Acid: Sources, Biosynthesis, Detection and Applications

5-Aminolevulinic acid (5-ALA) is the key precursor for the biosynthesis of tetrapyrrole compounds, with wide applications in medicine, agriculture and other burgeoning fields. Because of its potential applications and disadvantages of chemical synthesis, alternative biotechnological methods have drawn increasing attention. In this review, the recent progress in biosynthetic pathways and regulatory mechanisms of 5-ALA synthesis in biological hosts are summarized. The research progress on 5-ALA biosynthesis via the C4/C5 pathway in microbial cells is emphasized, and the corresponding biotechnological design strategies are highlighted and discussed in detail. In addition, the detection methods and applications of 5-ALA are also reviewed. Finally, perspectives on potential strategies for improving the biosynthesis of 5-ALA and understanding the related mechanisms to further promote its industrial application are conceived and proposed.

Effects of Selenium Supplementation on Rumen Microbiota, Rumen Fermentation, and Apparent Nutrient Digestibility of Ruminant Animals: A Review

Enzymes excreted by rumen microbiome facilitate the conversion of ingested plant materials into major nutrients (e.g., volatile fatty acids (VFA) and microbial proteins) required for animal growth. Diet, animal age, and health affect the structure of the rumen microbial community. Pathogenic organisms in the rumen negatively affect fermentation processes in favor of energy loss and animal deprivation of nutrients in ingested feed. Drawing from the ban on antibiotic use during the last decade, the livestock industry has been focused on increasing rumen microbial nutrient supply to ruminants through the use of natural supplements that are capable of promoting the activity of beneficial rumen microflora. Selenium (Se) is a trace mineral commonly used as a supplement to regulate animal metabolism. However, a clear understanding of its effects on rumen microbial composition and rumen fermentation is not available. This review summarized the available literature for the effects of Se on specific rumen microorganisms along with consequences for rumen fermentation and digestibility. Some positive effects on total VFA, the molar proportion of propionate, acetate to propionate ratio, ruminal NH3-N, pH, enzymatic activity, ruminal microbiome composition, and digestibility were recorded. Because Se nanoparticles (SeNPs) were more effective than other forms of Se, more studies are needed to compare the effectiveness of synthetic SeNPs and lactic acid bacteria enriched with sodium selenite as a biological source of SeNPs and probiotics. Future studies also need to evaluate the effect of dietary Se on methane emissions.

Supplementing rabbit diets with butylated hydroxyanisole affects oxidative stress, growth performance, and meat quality

Butylated hydroxyanisole (BHA) is a synthetic antioxidant analogous of vitamin E. It is used as a preservative to prevent free radical-mediated oxidation in high-fat foods, and this study's objective was to investigate the effects of BHA on oxidative stress and apoptosis in addition to delineating its efficacy as a growth-promoting feed additive. 60 weaned male rabbits (V-line) were randomly divided into four equal groups: BHA0.0 (control), BHA50, BHA100, and BHA150, administered basal diets with 0.0, 50, 100, and 150 mg BHA/kg of feed for 60 days. Animals were examined for growth performance, markers of oxidative stress and apoptosis, and meat characteristics. Compared to the control group, rabbits receiving BHA-supplemented diets exhibited increases in BW and average daily gain (P < 0.01), where BHA50 and BHA100 groups showed increased muscle content of methionine aspartic acid, serine, and glutamine (P < 0.05). These two groups also exhibited elevated catalase and superoxide dismutase activities and diminished malondialdehyde levels in the liver. Butylated hydroxyanisole upregulated fatty acid synthase gene (FASN), especially in BHA100 animals. Bcl-2-associated X/B-celllymphoma-2 (Bax/Bcl-2) ratio significantly increased in animals receiving higher doses of BHA, and the weight of the liver significantly increased following BHA treatment. Supplementing growing rabbits with lower doses of dietary BHA may promote growth performance and meat quality via maintaining the redox balance. Hence, the 50-100 mg/kg may be recommended as a safe and still effective feed additive as well as an oxidative stress attenuator.

Efficient solid-state fermentation for the production of 5-aminolevulinic acid enriched feed using recombinant Saccharomyces cerevisiae

Over the past decade, 5-aminolevulinic acid (5-ALA) has been highlighted as a promising functional feed additive and immunomodulator for improving the general health, immune response, and resistance to disease of livestock and poultry. However, it is very costly to produce 5-ALA using conventional chemical synthesis methods. Classical microbial fermentation fulfills the criteria of environmental friendliness, but the unsatisfactory titers still hinder actual industrial production. This study aimed to develop a solid-state fermentation (SSF) process that can be used to efficiently enrich feed with 5-ALA at a low cost. First, the endogenous 5-ALA synthase was overexpressed in Saccharomyces cerevisiae via integrating a copy of HEM1 gene into the chromosome and introducing a multi-copy plasmid pRS416-HEM1 which constitutively overexpresses HEM1 gene. The resulting strain ScA3 was able to produce 63.82 mg/L 5-ALA in shake-flask fermentation. After process optimization, a titer of 225.63 mg/kg dry materials, exceeding the usual effective dosage reported in animal trials, was achieved within 48 h through SSF of 20 kg feed in a 90-L steel drum. To our knowledge, this is the first report on combining microbial 5-ALA production with SSF in feed processing, which will hopefully promote the application and popularization of 5-ALA in the feed industry.

Effects of 5-Aminolevulinic Acid as a Supplement on Animal Performance, Iron Status, and Immune Response in Farm Animals: A Review

Efforts directed toward enhancing animals' productivity are focused on evaluating the effects of non-traditional feed additives that are safer than antibiotics, which have been banned because of their health hazards. Many studies used an amino acid that contributes to heme biosynthesis, known as 5-aminolevulinic acid (5-ALA), to promote the productivity of farm animals. However, these studies demonstrate inconsistent results. In order to develop a clear understanding of the effects of 5-ALA in farm animals, we comprehensively searched PubMed and Web of Science for studies evaluating 5-ALA effects on the performance, iron status, and immune response of different farm animals. The search retrieved 1369 publications, out of which 16 trials were relevant. The 5-ALA-relevant data and methodological attributes of these trials were extracted/evaluated by two independent researchers, based on a set of defined criteria. Samples were comprised of pigs, chickens, and dairy cows. The 5-ALA doses ranged from 2 mg to 1 g/kg of feed, and treatment duration ranged from 10 to 142 days. Overall, 5-ALA improved iron status in most studies and increased white blood cells count in 3 out of 10 studies, in addition to improving animals' cell-mediated immune response following immune stimulation with lipopolysaccharide. Inconsistent findings were reported for growth performance and egg production; however, a combination of 10 mg/kg of 5-ALA with 500 mg/kg of vitamin C promoted the highest egg production. In addition, 5-ALA improved milk protein concentration. In conclusion, 5-ALA can enhance farm animals' iron status and immune response; however, the heterogeneity of the reviewed studies limits the generalizability of the findings. Standard procedures and outcome measures are needed to confirm the benefits of 5-ALA. Attention should also be paid to any adverse effects.