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Enramycin, a common growth promoter utilized in chickens and pigs, is sensitive against Gram-positive bacteria, and the maximum residue limit (MRL) of enramycin set up by is 30 µg/kg. However, the methods have been reported for detecting enramycin have failed to meet the accuracy requirements, with the required limit of quantification being higher than the MRL. To address this issue, we developed a high-sensitive and robust analytical method based on ultrahigh-performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS), to determine enramycin residues in swine tissues, including liver, kidney, pork, and fat. The ENV cartridge was selected to cleanup and enrich analytes after being extracted using a mixture of 55% methanol containing 0.2 M hydrochloric acid. With comprehensively validation, this established method was found great linearity of enramycin in each tissue, with a coefficient of variation above 0.99. Satisfactory recoveries from four different spiking levels were acquired (70.99-101.40%) while the relative standard deviations were all below 9%. The limit of quantification of enramycin in the present study is 5 µg/kg in fat and 10 µg/kg in other tissues, meeting the requirements for conducting the corresponding safety evaluation study. This method was demonstrated with excellent specificity, stability, and high sensitivity. To conclude, this novel approach is sufficiently sensitive and robust for the safety evaluation of enramycin in food products. [ABSTRACT FROM AUTHOR]

ABSTRACT This study investigated the effects of dietary aqueous extract of red propolis (AERP) on the performance, egg quality, antioxidant capacity, and fecal microbiota of laying quails. A total of 120 52-day-old laying quails were randomly divided into four dietary treatments, each consisting of six replicates of 5 animals. The dietary treatments were a control basal diet and basal diets with of 1g of AERP, 2g of AERP, and 0.01g of enramycin per kg of feed for 63 days. Productive performance results such as percentage of egg production, feed intake per quail per day, average egg weight, egg mass, and feed conversion rate showed no significant difference between treatments. On the other hand, eggs from quails fed with red propolis showed darker yolk, higher intensity of red, and lower intensity of yellow (p

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ABSTRACT: Since antibiotic resistance is a global health issues, the use of antibiotics in animal feed for growth promotion has been restricted in many countries. Bacillus licheniformis probiotic is a potential alternative to antibiotics for increasing poultry performance. Through metagenomic sequencing, this study investigated the effects of B. licheniformis–fermented products (BLFPs) and enramycin on the microbial community composition and antibiotic resistance gene (ARG) distribution in the cecal digesta of broilers at the age of 35 d. In total, 144 one-day-old male broiler chicks (Ross 308) were randomly assigned to 4 dietary treatments as follows: basal diet (control [C] group), basal diet plus 10 mg/kg enramycin (E group), basal diet plus 1 g/kg BLFPs (L group), and basal diet plus 3 g/kg BLFPs (H group), with 6 replicate cages per treatment group and 6 birds per cage. The results indicated that the cecal alpha diversity (richness and evenness) of bacterial species was higher in the H group than in the C group. Principal coordinate analysis of microbiota and the ARG composition indicated clear differences among the cecal samples of the groups. In the cecal digesta, the abundance of active bacteria associated with probiotic properties, such as Lactobacillus crispatus and Akkermansia muciniphila, was higher in the H group than in the other groups. Enramycin treatment promoted the expression of peptide (bcrA), glycopeptide (vanRI), and lincosamide (lsaE) resistance genes but inhibited the expression of aminocoumarin (parY) and pleuromutilin (TaeA) resistance genes. BLFP (1 and 3 g/kg) treatment suppressed the expression of aminoglycoside (ANT(6)-Ib), streptogramin (vatB), and peptide (ugd) resistance genes but enhanced the expression of macrolide (efrA) and aminocoumarin (novA) resistance genes. The abundance of peptide resistance genes in Bacteroides spp. was lower in the H group than in the C group. The abundance of lincosamide resistance genes in Lactobacillus spp. was higher in the E group than in the other groups. These results demonstrated that differential changes in the structure of 3 g/kg BLFPs and enramycin-induced cecal microbial communities accompany changes in the abundance of bacterial hosts carrying specific ARGs in the cecal microbiota of broilers.

The emergence and spread of antibiotic resistance genes in pathogenic microorganisms have resulted in many countries restricting the use of antibiotics as growth promoters in animal feed. The combined use of essential oils and organic acids can help maintain intestinal health, improve animal growth performance, and alleviate the negative effects of banned antibiotics for certain economically important animals. Although the modes of action for the combined dietary supplementation of essential oils and organic acids such as thymol-citric acid (EOA1) and thymol-butyric acid (EOA2) remain unclear, it is speculated that their activities are achieved through beneficial modulation of gastrointestinal microbial communities and inhibition of pathogen growth. In this study, 16S rDNA amplicon sequencing was used to analyze the effects of treatment with EOA1 and EOA2 on the jejunal, cecal, and fecal microbial communities of Cobb broilers while also evaluating effects over different broiler ages. The intestinal microbial communities of broilers developed with increasing age, and Lactobacillus gradually came to dominate the intestinal communities of treated broilers. Further, the microbial communities of feces were more complex than those of the jejuna and ceca. We systematically elucidate that the longitudinal changes in the intestinal microbial communities of Cobb broiler chickens at different ages. Meanwhile, we found that the addition of EOA1 or EOA2 to the diet: (1) inhibited the proliferation of Ralstonia pickettii and Alcaligenaceae in the jejuna on day 28, (2) promoted the colonization and growth of beneficial bacteria such as Lactobacillus, Clostridia, and Bacteroidia at various growth stages, and (3) enriched the abundance of certain microbiota functions, including biological pathways related to metabolism (e.g., enzyme families). Taken together, the results of this study demonstrate that EOA1 and EOA2 dietary supplementation can affect various microbial metabolic pathways related to the metabolism and absorption of nutrients via regulation of the intestinal microbial community structures of Cobb broilers.

The emergence and spread of antibiotic resistance genes in pathogenic microorganisms have resulted in many countries restricting the use of antibiotics as growth promoters in animal feed. The combined use of essential oils and organic acids can help maintain intestinal health, improve animal growth performance, and alleviate the negative effects of banned antibiotics for certain economically important animals. Although the modes of action for the combined dietary supplementation of essential oils and organic acids such as thymol-citric acid (EOA1) and thymol-butyric acid (EOA2) remain unclear, it is speculated that their activities are achieved through beneficial modulation of gastrointestinal microbial communities and inhibition of pathogen growth. In this study, 16S rDNA amplicon sequencing was used to analyze the effects of treatment with EOA1 and EOA2 on the jejunal, cecal, and fecal microbial communities of Cobb broilers while also evaluating effects over different broiler ages. The intestinal microbial communities of broilers developed with increasing age, and Lactobacillus gradually came to dominate the intestinal communities of treated broilers. Further, the microbial communities of feces were more complex than those of the jejuna and ceca. We systematically elucidate that the longitudinal changes in the intestinal microbial communities of Cobb broiler chickens at different ages. Meanwhile, we found that the addition of EOA1 or EOA2 to the diet: (1) inhibited the proliferation of Ralstonia pickettii and Alcaligenaceae in the jejuna on day 28, (2) promoted the colonization and growth of beneficial bacteria such as Lactobacillus , Clostridia, and Bacteroidia at various growth stages, and (3) enriched the abundance of certain microbiota functions, including biological pathways related to metabolism (e.g., enzyme families). Taken together, the results of this study demonstrate that EOA1 and EOA2 dietary supplementation can affect various microbial metabolic pathways related to the metabolism and absorption of nutrients via regulation of the intestinal microbial community structures of Cobb broilers. [ABSTRACT FROM AUTHOR]

To achieve rapid detection of enramycin in feed, we employed the competitive inhibition method to develop a colloidal gold immunochromatographic test strip based on the anti-enramycin A monoclonal antibody (anti-Er.A-mAb). Colloidal gold probes were prepared with a laboratory-prepared high-purity anti-Er.A-mAb. The effects of pH, antibody titer, and antigen concentration (test line) on the test strip performance were investigated. The colloidal gold test strip prepared with 8 μL potassium carbonate addition, 4 µg/mL antibody, 1.0 mg/mL antigen (test line), and 3 μL gold-labeled antibody showed acceptable specificity and a low limit of detection. The test strip showed the detection limit of 25 ng/mL for enramycin A, with a linear range of 25-300 ng/mL. The experiments on the feed with positive sample addition proved that the test strip had good repeatability and was more sensitive than high-performance liquid chromatography, being applicable for the rapid detection of enramycin in large batches of feed samples.

This study was conducted to evaluate the productive performance, intestinal health, and description of the cecum microbiota in broilers supplemented with β-mannanases (MNs) and bacteriophages (BPs). Six hundred one-day-old broilers were divided into four groups and fed one of the following diets: CON—corn–soybean meal + 10 ppm enramycin (ENR); MN: CON + 500 ppm MN; BP: CON + 500 ppm BP; MN + BP: BP + 500 ppm MN. The BP and MN factors showed similar performances to ENR. MN improved the concentration of IgA in the jejunum at 35 days of age. The morphometric index (IM) of the thymus increased by adding MN, while BP increased the liver and thymus IM. The histological analysis showed that BP and MN improved the intestinal morphology. MN + BP showed a tendency to decrease the abundance of Proteobacteria and increase the abundance of Bacteroidetes, indicating better microbiota function. In conclusion, our results demonstrate that the combination of MN + BP has potential in poultry nutrition; however, we highly recommend further experiments to confirm this hypothesis.

Simple Summary: For several years, antibiotic growth promoters (AGPs) have been used in poultry production; however, with the recent ban on the use of AGPs, several alternatives have been evaluated. In the present work, we evaluated the use of β-mannanases and bacteriophages as an alternative to AGPs. This study demonstrates that supplementation with β-mannanases, bacteriophages, or a mix of these two does not affect the productive performance in broilers fed corn–soybean meal. The mixture of β-mannanases and bacteriophages promoted the abundance of beneficial microorganisms in the cecum. These preliminary results suggest that β-mannanases and bacteriophages have potential as alternatives to AGPs in poultry production. This study was conducted to evaluate the productive performance, intestinal health, and description of the cecum microbiota in broilers supplemented with β-mannanases (MNs) and bacteriophages (BPs). Six hundred one-day-old broilers were divided into four groups and fed one of the following diets: CON—corn–soybean meal + 10 ppm enramycin (ENR); MN: CON + 500 ppm MN; BP: CON + 500 ppm BP; MN + BP: BP + 500 ppm MN. The BP and MN factors showed similar performances to ENR. MN improved the concentration of IgA in the jejunum at 35 days of age. The morphometric index (IM) of the thymus increased by adding MN, while BP increased the liver and thymus IM. The histological analysis showed that BP and MN improved the intestinal morphology. MN + BP showed a tendency to decrease the abundance of Proteobacteria and increase the abundance of Bacteroidetes, indicating better microbiota function. In conclusion, our results demonstrate that the combination of MN + BP has potential in poultry nutrition; however, we highly recommend further experiments to confirm this hypothesis. [ABSTRACT FROM AUTHOR]