Developmental Programming of the Fetal Immune System by Maternal Western-Style Diet: Mechanisms and Implications for Disease Pathways in the Offspring

Maternal obesity and over/undernutrition can have a long-lasting impact on offspring health during critical periods in the first 1000 days of life. Children born to mothers with obesity have reduced immune responses to stimuli which increase susceptibility to infections. Recently, maternal western-style diets (WSDs), high in fat and simple sugars, have been associated with skewing neonatal immune cell development, and recent evidence suggests that dysregulation of innate immunity in early life has long-term consequences on metabolic diseases and behavioral disorders in later life. Several factors contribute to abnormal innate immune tolerance or trained immunity, including changes in gut microbiota, metabolites, and epigenetic modifications. Critical knowledge gaps remain regarding the mechanisms whereby these factors impact fetal and postnatal immune cell development, especially in precursor stem cells in bone marrow and fetal liver. Components of the maternal microbiota that are transferred from mothers consuming a WSD to their offspring are understudied and identifying cause and effect on neonatal innate and adaptive immune development needs to be refined. Tools including single-cell RNA-sequencing, epigenetic analysis, and spatial location of specific immune cells in liver and bone marrow are critical for understanding immune system programming. Considering the vital role immune function plays in offspring health, it will be important to understand how maternal diets can control developmental programming of innate and adaptive immunity.

Antimicrobial activity of phenyllactic acid against Klebsiella pneumoniae and its effect on cell wall membrane and genomic DNA

As Klebsiella pneumoniae (KP) has acquired high levels of resistance to multiple antibiotics, it is considered a worldwide pathogen of concern, and substitutes for traditional antibiotics are urgently needed. 3-Phenyllactic acid (PLA) has been reported to have antimicrobial activity against food-borne bacteria. However, there was no experiment evidence for the exact antibacterial effect and mechanism of PLA kills pathogenic KP. In this study, the Oxford cup method indicated that PLA is effective to KP with a minimum inhibitory concentration of 2.5 mg/mL. Furthermore, PLA inhibited the growth and biofilm formation of in a time- and concentration-dependent manner. In vivo, PLA could significantly increase the survival rate of infected mice and reduce the pathological tissue damage. The antibacterial mode of PLA against KP was further explored. Firstly, scanning electron microscopy illustrated the disruption of cellular ultrastructure caused by PLA. Secondly, measurement of leaked alkaline phosphatase demonstrated that PLA disrupted the cell wall integrity of KP and flow cytometry analysis with propidium iodide staining suggested that PLA damaged the cell membrane integrity. Finally, the results of fluorescence spectroscopy and agarose gel electrophoresis demonstrated that PLA bound to genomic DNA and initiated its degradation. The anti-KP mode of action of PLA was attributed to the destruction of the cell wall, membrane, and genomic DNA binding. These findings suggest that PLA has great potential applications as antibiotic substitutes in feed additives against KP infection in animals.

A two-enzyme system in an amorphous metal-organic framework for the synthesis of D-phenyllactic acid

In this study, we synthesized an amorphous metal-organic framework by adjusting the concentration of precursors, and established a two-enzyme system consisting of lactate dehydrogenase (LDH) and glucose dehydrogenase (GDH), which successfully achieved coenzyme recycling, and applied it to the synthesis of D-phenyllactic acid (D-PLA). The prepared two-enzyme-MOF hybrid material was characterized using XRD, SEM/EDS, XPS, FT-IR, TGA, CLSM, etc. In addition, reaction kinetic studies indicated that the MOF-encapsulated two-enzyme system exhibited faster initial reaction velocities than free enzymes due to its amorphous ZIF-generated mesoporous structure. Furthermore, the pH stability and temperature stability of the biocatalyst were evaluated, and the results indicated a significant improvement compared to the free enzymes. Moreover, the amorphous structure of the mesopores still maintained the shielding effect and protected the enzyme structure from damage by proteinase K and organic solvents. Finally, the remaining activity of the biocatalyst for the synthesis of D-PLA reached 77% after 6 cycles of use, and the coenzyme regeneration still maintained at 63%, while the biocatalyst also retained 70% and 68% residual activity for the synthesis of D-PLA after 12 days of storage at 4 °C and 25 °C, respectively. This study provides a reference for the design of MOF-based multi-enzyme biocatalysts.

Recent development of phenyllactic acid: physicochemical properties, biotechnological production strategies and applications

Phenyllactic acid (PLA) is capable of inhibiting the growth of many microorganisms, showing a broad-spectrum antimicrobial property, which allows it to hold vast applications in the: food, feed, pharmaceutical, and cosmetic industries, especially in the field of food safety. Recently, the production of PLA has garnered considerable attention due to the increasing awareness of food safety from the public. Accordingly, this review mainly updates the recent development for the production of PLA through microbial fermentation and whole-cell catalysis (expression single-, double-, and triple-enzyme) strategies. Firstly, the: physicochemical properties, existing sources, and measurement methods of PLA are systematically covered. Then, the inhibition spectrum of PLA is summarized, and synchronously, the antimicrobial and anti-biofilm mechanisms of PLA on commonly pathogenic microorganisms in foods are described in detail, thereby clarifying the reason for extending the shelf life of foods. Additionally, the factors affecting the production of PLA are summarized from the biosynthesis and catabolism pathway of PLA in microorganisms, as well as external environmental parameters insights. Finally, the downstream treatment process and applications of PLA are discussed and outlined. In the future, clinical data should be supplemented with the metabolic kinetics of PLA in humans and to evaluate animal toxicology, to enable regulatory use of PLA as a food additive. A food-grade host, such as Bacillus subtilis and Lactococcus lactis, should also be developed as a cell vector expressing enzymes for PLA production from a food safety perspective.

Redefining methods for augmenting lactic acid bacteria robustness and phenyllactic acid biocatalysis: Integration valorizes simplicity

The production of phenyllactic acid (PLA) has been reported by several researchers, but so far, no mention has been made of augmented PLA production using an orchestrated assembly of simple techniques integrated to improve lactic acid bacteria (LAB) metabolism for the same. This review summarizes sequentially tailoring LAB growth and metabolism for augmented PLA catalysis through several strategies like monitoring LAB sustenance by choosing appropriate starter PLA-producing LAB strains isolated from natural environments, with desirably fastidious growth rates, properties like acidification, proteolysis, bacteriophage-resistance, aromatic/texturing-features, etc.; entrapping chosen LAB strains in novel cryogels and/or co-cultivating two/more LAB strains to improve their biotransformation potential and promote growth dependency/sustainability; adopting adaptive evolution methods designed to improve LAB strains under selection pressure inducing desired phenotypes tolerant to stress factors like heat, salt, acid, and solvent; monitoring physico-chemical LAB fermentation factors like temperature, pH, dissolved oxygen content, enzymes, and cofactors for PLA biosynthesis; and modulating purification/downstream processes to extract substantial PLA yields. This review paper serves as a comprehensive preliminary guide that can evoke a strategic experimental plan to produce industrial-scale PLA yields using simple techniques orchestrated together in the pursuit of conserving time, effort, and resources.

Blood metabolic and physiological profiles of Bama miniature pigs at different growth stages

Background

Bama miniature pigs aged between six (6 M) and twelve months (12 M) are usually used in human medical research as laboratory pigs. However, the difference in serum metabolic profiles from 6 to 12 M-old pigs remains unclear. This study aimed to identify the metabolic and physiological profiles present in the blood to further explain changes in Bama miniature pig growth. We collected blood samples from 6 M-, eight-month- (8 M-), ten-month- (10 M-), and 12 M-old healthy Guangxi Bama miniature pigs. A total of 20 blood physiological indices (BPIs) were measured: seven for white blood cells, eight for red blood cells, and five for platelet indices. Liquid chromatography and mass spectrometry-based non-targeted metabolomic approaches were used to analyze the difference in metabolites. The associations between the differences were calculated using Spearman correlations with Benjamini–Hochberg adjustment. The 100 most abundant differential metabolites were selected for analysis of their metabolic profiles.

Results

There were no significant differences in BPIs at different ages, but the mid cell ratio and red blood cell number increased with age. Seven BPIs in Bama miniature pigs were closer to human BPIs than to mouse BPIs. A total of 14 and 25 significant differential metabolites were identified in 6 M vs. 12 M and 8 M vs. 12 M, respectively. In total, 9 and 18 amino acids and their derivatives showed significantly lower concentrations in 6 M- and 8 M-old pigs than in 12 M-old pigs. They were identified as the core significantly different metabolites between the age groups 6 M vs. 12 M and 8 M vs. 12 M. Half of the enriched pathways were the amino acids metabolism pathways. The concentration of six amino acids (dl-tryptophan, phenylacetylglycine, muramic acid, N-acetylornithine, l(−)-pipecolinic acid, and creatine) and their derivatives increased with age. A total of 61 of the top 100 most abundant metabolites were annotated. The metabolic profiles contained 14 amino acids and derivatives, six bile acids and derivatives, 19 fatty acids and derivatives, and 22 others. The concentrations of fatty acids and derivatives were found to be inversely proportional to those of amino acids and derivatives.

Conclusion

These findings suggest high levels of MID cell ratio, red blood count, and amino acids in 12 M-old pigs as indicators for improved body function over time in Bama miniature pigs, similar to those in human development. This makes the pig a more suitable medical model organism than the mouse. The results of this study are limited to the characteristics of blood metabolism in the inbred Bama miniature pigs, and the effects of impacting factors such as breed, age, sex, health status and nutritional level should be considered when studying other pig populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40813-022-00278-7.

Unique Probiotic Properties and Bioactive Metabolites of Saccharomyces boulardii

Saccharomyces boulardii (S. boulardii) is a probiotic and is widely used to improve the nutritional and functional value of food. This study aimed to compare the probiotic properties of S. boulardii and Saccharomyces cerevisiae. A series of in vitro probiotic experiments was performed, including simulated gastrointestinal digestion, bile salt tolerance, hydrophobicity, self-aggregation, and antioxidant and antibacterial properties. Self-aggregation and hydrophobic properties of S. boulardii were relatively poor, but they showed high tolerance, antioxidant properties, and broad antibacterial properties. In addition, non-targeted metabolomics was used to comprehensively analyze the active metabolites of S. boulardii and the metabolic differences between S. boulardii and S. cerevisiae were compared. Saccharomyces boulardii produced many bioactive metabolites, which generally showed antioxidant, antibacterial, antitumor, anti-inflammatory, and other properties. In contrast to S. cerevisiae, S. boulardii produced phenyllactic acid and 2-hydroxyisocaproic acid. There were also significant differences in their metabolic pathways. These results may be of great significance in the medical and food industries and provide a basis for understanding the metabolism of S. boulardii. It also shows that metabolomics is an effective and novel method for screening microbial functional metabolites and identifying functional differences between similar microorganisms.

Phenyl lactic acid alleviates Samonella Typhimurium-induced colitis via regulating microbiota composition, SCFA production and inflammatory responses

Colitis caused by non-typhoidal Salmonella (NST) infection is increasingly serious and widespread, so new effective treatment strategies with little or no side-effects are urgently needed. Our previous research found that phenyl lactic acid (PLA) derived from Lactobacillus plantarum ZJ316 can effectively inhibit Salmonella enterica Typhimurium (S. Typhimurium). In this study, we further investigated the protective effects of this PLA against S. Typhimurium-induced colitis in mice. An infection model was established using female C57BL/6J mice by oral administration of 109 CFU mL-1 of S. Typhimurium, and PLA was supplied for 10 days after infection. In colitic mice, PLA administration reduced the disease activity index, prevented the colon shortening and spleen enlargement, decreased liver enzyme (AST and ALT) activities, and alleviated the colonic tissue damage. RT-qPCR analysis showed that PLA significantly down-regulated the levels of NF-κB, TLR4 and pro-inflammatory cytokines (IFN-γ, IL-1β and TNF-α), but stimulated the mRNA expression of the anti-inflammatory cytokine IL-10. Changes in intestinal microecology were analyzed by 16S rRNA sequencing. PLA modulated colonic microbiota dysbiosis by increasing the abundance of Lactobacillus, Butyricicoccus and Roseburia, and reducing Salmonella and Alloprevotella at the genus level. In addition, PLA significantly increased the concentrations of short-chain fatty acids (SCFAs) in the colon, especially propionic acid and butyric acid. These findings revealed that PLA has potential benefits on alleviating S. Typhimurium-induced colitis mainly through intestinal microbiota regulation and inflammation elimination, providing a new perspective for the NTS infection treatment strategy.

Dietary Supplementation of EGF Ameliorates the Negatively Effects of LPS on Early-Weaning Piglets: From Views of Growth Performance, Nutrient Digestibility, Microelement Absorption and Possible Mechanisms

Simple Summary

This study aims to investigate how epidermal growth factor (EGF) attenuates the effect of lipopolysaccharide (LPS) on the growth performance, nutrient digestibility, microelement absorption of early-weaned pigs. A total of 48 early weaned piglets were randomly distributed to four groups consisting of a 2 × 2 factorial design. The main factors were the level of LPS (H_LPS = high LPS: 100 μg/kg body weight; Z_LPS = low LPS: 0 μg/kg body weight) and EGF (H_EGF = high EGF: 2 mg/kg diet; Z_EGF = low EGF: 0 mg/kg diet). Each group had four replicates and each replicate consisted of three piglets. The results showed that H_LPS level decreased the growth performance and the apparent digestibility of crude fat, while H_EGF level increased the average daily feed intake. The concentration of most microelements in the gastrointestinal tract chyme and feces were increased by H_LPS level and decreased by H_EGF level. The expression levels of most microelement transport-relative genes in the mucosa of gastrointestinal tissues were decreased by H_LPS level and increased by H_EGF level. In conclusion, dietary EGF could attenuate the negative effect of LPS exposure on the apparent digestibility of crude fat and microelement absorption through changing the expression levels of microelement transport-relative genes. EGF can be used as an additive to increase the essential trace elements absorption in the early weaning piglets.

Abstract

Epidermal growth factor (EGF) plays an important role in nutrients absorption. However, whether it can be an effective additive to improve the growth performance and nutrients absorption in lipopolysaccharide (LPS) challenged early weaning piglets is still unknown. A 14-days trial was conducted to investigate how EGF attenuates the effect of LPS on the growth performance, nutrient digestibility, microelement absorption of early-weaned pigs, and study the underlying mechanism. A total of 48 early weaned piglets, aged 25 days, were randomly distributed to four groups (control, EGF, LPS and EGF + LPS groups) consisting of a 2 × 2 factorial design. The main factors were the level of LPS (H_LPS = high LPS: 100 μg/kg body weight; Z_LPS = low LPS: 0 μg/kg body weight) and EGF (H_EGF = high EGF: 2 mg/kg diet; Z_EGF = low EGF: 0 mg/kg diet). Each group had four replicates and each replicate consisted of three piglets. The results showed that piglets injected with H_LPS level significantly decreased the average daily gain (ADG), and significantly increased the feed conversion ratio (FCR) compared with the piglets injected with Z_LPS level, while piglets fed H_EGF level significantly increased the average daily feed intake (ADFI) compared with the piglets fed Z_EGF level (p < 0.05). Piglets injected with H_LPS level significantly decreased the apparent digestibility of crude fat compared with the piglets injected with Z_LPS level (p < 0.05). Piglets injected with H_LPS level significantly increased the concentration of most microelements in the gastrointestinal tract chyme and feces, and significantly decreased the expression levels of most microelement transport-relative genes in the mucosa of gastrointestinal tissues compared with the piglets injected with Z_LPS level (p < 0.05). Piglets fed H_EGF level significantly decreased the concentration of microelement in the gastrointestinal tract chyme and feces, and significantly increased the expression levels of the microelement transport-relative genes in the mucosa of gastrointestinal tissues compared with the piglets fed Z_EGF level (p < 0.05). In conclusion, dietary EGF could attenuate the negative effect of LPS exposure on the apparent digestibility of crude fat and microelement absorption of early-weaning piglets. EGF and LPS influenced the absorption of essential trace element through changing the expression levels of microelement transport-relative genes in the mucosa of gastrointestinal tissues. In the early weaning piglets, EGF can be used as an additive to increase the essential trace elements absorption.

Time for a Paradigm Shift in Animal Nutrition Metabolic Pathway: Dietary Inclusion of Organic Acids on the Production Parameters, Nutrient Digestibility, and Meat Quality Traits of Swine and Broilers

Because the application of antibiotic growth promoters (AGP) causes accelerated adverse effects on the animal diet, the scientific community has taken progressive steps to enhance sustainable animal productivity without using AGP in animal nutrition. Organic acids (OAs) are non-antibiotic feed additives and a promising feeding strategy in the swine and broiler industry. Mechanistically, OAs improve productivity through multiple and diverse pathways in: (a) reduction of pathogenic bacteria in the gastro-intestinal tract (GIT) by reducing the gut pH; (b) boosting the digestibility of nutrients by facilitating digestive enzyme secretion and increasing feed retention time in the gut system; and (c) having a positive impact and preventing meat quality deterioration without leaving any chemical residues. Recent studies have reported the effectiveness of using encapsulated OAs and synergistic mechanisms of OAs combinations in swine and broiler productivity. On the other hand, the synergistic mechanisms of OAs and the optimal combination of OAs in the animal diet are not completely understood, and further intensive scientific explorations are needed. Moreover, the ultimate production parameters are not similar owing to the type of OAs, concentration level, growth phase, health status of animals, hygienic standards, and environmental factors. Thus, those factors need to be considered before implementing OAs in feeding practices. In conclusion, the current review evaluates the basics of OAs, mode of action, novel strategies to enhance utilization, influence on growth performances, nutrient digestibility, and meat quality traits of swine and broilers and their potential concerns regarding utilization.

Effects of microencapsulated organic acids on growth performance, nutrient digestibility, fecal microbial counts, and blood profiles in weaning pigs

This study was conducted to investigate the efficiency of a microencapsulated mixture of organic acids (MOA) with low protein in piglet feed on growth performance, diarrhea score, nutrient digestibility, fecal microbial counts, and blood profiles in weaning pigs. A total of 80 pigs [(Landrace × Yorkshire) × Duroc; 6.8 ± 0.48 kg] were randomly assigned to four dietary treatment groups: high protein (HP); low protein (LP); MOA1, LP + 0.2% MOA; and MOA2, LP + 0.3% MOA. The MOA2 group had higher average daily weight gains (during days 0–14 and days 0–28), diarrhea score (during days 0–14, during days 14–28 and days 0–28) and greater digestibility of dry matter (days 14 and 28) compared to the LP group (p < 0.05). However, there were no significant differences (p > 0.05) between the pigs fed diets with the MOA1 and MOA2 in blood profiles and fecal microflora. In conclusion, this study indicates that piglets fed 0.3% MOA in low protein diets maintained similar growth performance and nutrient digestibility, but alleviated the incidence of diarrhea compared to piglets fed high protein diets.

iTRAQ-based quantitative proteomic analysis of synergistic antibacterial mechanism of phenyllactic acid and lactic acid against Bacillus cereus

Phenyllactic acid (PLA) as a phenolic acid by lactic acid (LA) bacteria shows enhanced antibacterial activity when coexisting with LA, while the antibacterial mechanism of PLA combined with LA was unknown. Hence, the antibacterial mechanism of PLA and LA was investigated against Bacillus cereus. Flow cytometry and TEM analysis demonstrated that single PLA and LA disrupted the membrane integrity and the morphology, while combined PLA and LA synergistically enhanced the damage. iTRAQ-based proteomic analysis suggested that PLA down-regulated kdpB and inhibited K⁺ transport, disturbed the function of ribosome and expression of competence genes; LA down-regulated periplasmic phosphorus-binding proteins and inhibited phosphorus transport, disturbed the function of ribosome, TCA cycle, as well as purine and pyrimidine metabolism; and combined PLA and LA inhibited K⁺ and phosphorus transport, and influenced the synthesis of purine and pyrimidine metabolism. The investigation could provide some insights into the application of PLA in food preservation.

Organic Acids Mixture as a Dietary Additive for Pigs-A Review

Simple Summary

Many countries have enforced a ban on the use of all antibiotics in animal feed as growth promoters due to public health concerns about the emergence of antimicrobial resistance. There are a variety of candidates for the replacement of antibiotic growth promoters like probiotic, prebiotics, herbs, or essential oil. Organic acids have been suggested as alternatives to replace antibiotics in the diets of animals. It is reported that the lower the pKa of the OAs, the greater its effect on the reduction of stomach pH and the lower its antimicrobial effect in the more distal portions during its transit through the GIT which eventually will have better effect on animal’s health as well as their performance. Herein, we focus on the use of organic acids’ mixture as feed additives in the diet of swine in term of their immune system, gut health, nutrient digestibility, and growth performance as well as gas emission.

Abstract

Due to the increasing safety concerns about the risk of spreading antibiotic resistance in the environment, and the presence of chemical residues in animal products, using organic acids (OAs) to replace antibiotic in the diet of farm animals has increased considerably in recent years. It has been suggested that OAs could attribute to diverse elements such as antimicrobial activity, decreasing the pH of digesta particularly in the gastrointestinal tract (GIT), slowing feed transit in the GIT to maximize feed digestion and nutrient absorption, inducing enzyme secretion and activity in the small intestine, and providing nutrients to intestinal tissue. It has been reported that OAs mixture might be more effective than individual OAs due to the synergistic effects of different pKa values and have a broad-spectrum activity. In conclusion, this review showed that an OA mixture, which can improve nutrient digestibility and growth performance, modulate intestinal bacterial populations and improve gut health, as well as decreasing gas emission, can be used as alternative to antibiotic growth promoters. However, the results of OA mixtures are not always consistent, and the response to dietary OAs could be affected by the type of OAs, dosage, feed formula, and the age of animals. In this review, we will give an overview of the current use of OAs mixture in swine feed.

Enzymological characterization of a novel d-lactate dehydrogenase from Lactobacillus rossiae and its application in d-phenyllactic acid synthesis

A novel lactate dehydrogenase gene, named lrldh, was cloned from Lactobacillus rossiae and heterologously expressed in Escherichia coli. The lactate dehydrogenase LrLDH is NADH-dependent with a molecular weight of approximately 39 kDa. It is active at 40 °C and pH 6.5 and stable in a neutral to alkaline environment below 35 °C. The kinetic constants, including maximal reaction rate (V _max), apparent Michaelis-Menten constant (K _m), turnover number (K _cat) and catalytic efficiency (K _cat/K _m) for phenylpyruvic acid were 1.95 U mg^-1, 2.83 mM, 12.29 s^-1, and 4.34 mM^-1 s^-1, respectively. Using whole cells of recombinant E. coli/pET28a-lrldh, without coexpression of a cofactor regeneration system, 20.5 g l^-1 d-phenyllactic acid with ee above 99% was produced from phenylpyruvic acid in a fed-batch biotransformation process, with a productivity of 49.2 g l^-1 d^-1. Moreover, LrLDH has broad substrate specificity to a range of ketones, keto acids and ketonic esters. Taken together, LrLDH is a promising biocatalyst for the efficient synthesis of d-phenyllactic acid and other fine chemicals.

Effect of supplemented microencapsulated zinc oxide and organic acids and pure botanicals on growth performance, nutrient digestibility, blood profiles, feces microflora, and zinc level of feces in weanling pigs

A total of 125 crossbred pigs with an initial body weight (BW) of 7.66 ± 1.30 kg were randomly distributed into one of five dietary treatments. Each treatment had five replicate pens with five pigs per pen. Treatments were as followed: (1) CON, control diet; (2) zinc oxide (ZO), CON + 0.3% ZO; (3) ZOM, CON + 0.3% ZO + 0.1% microencapsulated organic acids and pure botanicals (MOP); (4) microencapsulated zinc oxide (MZO), CON + 0.03% MZO; and (5) MZOM, CON + 0.03% MZO + 0.1% MOP. The MZO group had higher (P = 0.03) final BW than ZO group and also had higher (P = 0.04, 0.01) average daily gain and gain/feed ratio compared with ZO group during days 15–34 and throughout the experimental period. The MZO and MZOM had higher (P < 0.05) apparent total tract digestibility (ATTD) of dry matter (DM) and energy than ZO. Less (P < 0.05) feces Escherichia coli shedding was observed in the ZOM and MZOM diets compared with CON; the MZO had lowered (P = 0.001) zinc level in feces than ZO and CON. In conclusion, results indicated that supplementation with 0.3% MZO could improve the growth performance and ATTD of DM; inclusion of 0.1% MOP could decrease feces E. coli shedding and also decrease the zinc level in feces in weanling pigs.

Effects of microencapsulated complex of organic acids and essential oils on growth performance, nutrient retention, blood profiles, fecal microflora, and lean meat percentage in weaning to finishing pigs

A total of 90 pigs (6.47 ± 0.27 kg; 21 d of age) were used in this 22 wk feeding trial to evaluate the effect of microencapsulated complex of organic acids and essential oils (MOE) on growth performance, nutrient retention, blood profile, fecal microflora, and lean meat percentage in pigs. Pigs were randomly distributed to one of three treatment groups (six replicate pens per treatment, five pigs per pen). Dietary treatments were CON, basal diet; MOE1, basal + 0.1% MOE; and MOE2, basal diet + 0.2% MOE. The average daily gain, average daily feed intake, and feed efficiency ratio were significantly different among treatments (P < 0.05). The apparent total tract digestibility of dry matter was linearly increased (P < 0.05) by MOE2. Red blood cells and immunoglobulin G were significantly different in pigs fed MOE (P < 0.05). The Lactobacillus concentration linearly increased (P < 0.05) in MOE2 treatments compared with other treatments. The meat color (a*, redness) and drip loss decreased linearly (P < 0.05) with increasing level of MOE. In conclusion, MOE supplementation could improve growth performance, nutrient retention, blood profile, fecal microflora, and meat quality in weaning to finishing pigs.

Effects of a matrix-coated organic acids and medium-chain fatty acids blend on performance, and in vitro fecal noxious gas emissions in growing pigs fed in-feed antibiotic-free diets

This study evaluated the efficacy of a matrix-coated organic acids and medium-chain fatty acids blend (MCOFA) in growing pigs. Ninety six pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 47.71 ± 3.73 kg were used in a 6 wk experiment. Pigs were allotted to diets containing 0 or 2 g kg−1 of MCOFA, and 0 or 2.5 g kg−1 of antibiotic growth promoters (AGP) according to a 2 × 2 factorial arrangement of treatments. Pigs fed diets supplemented with MCOFA had improved growth efficiency compared with those fed a diet without MCOFA (P < 0.05). Pigs receiving the diets supplemented with both AGP and MCOFA had higher apparent total tract digestibility of crude protein, dry matter, fat, and gross energy (P < 0.05). Pigs fed AGP × MCOFA diet had increased serum urea nitrogen (P < 0.05). Pigs fed diets supplemented with AGP had reduced fecal ammonia (NH3) gas emissions compared with those fed without AGP (P < 0.05). Moreover, pigs fed diets supplemented with MCOFA had reduced fecal NH3 and acetic acid gas emissions compared with those fed without MCOFA (P < 0.05). In conclusion, dietary supplementation with MCOFA improved performance in growing pigs.

Characterization of a d-Lactate Dehydrogenase from Lactobacillus fermentum JN248 with High Phenylpyruvate Reductive Activity

Phenyllactic acid (PLA) is a novel antimicrobial compound. A novel NADH-dependent d-lactate dehydrogenase (d-LDH), named as LF-d-LDH0653, with high phenylpyruvate (PPA) reducing activity was isolated from Lactobacillus fermentum JN248. Its optimum pH and temperature were 8.0 and 50 °C, respectively. The Michaelis-Menten constant (K_m ), turnover number (k_cat ), and catalytic efficiency (k_cat /K_m ) for NADH were 1.20 mmol/L, 67.39 s^-1 , and 56.16 (mmol/L)^-1 s^-1 , respectively. The (K_m ), (k_cat ), and (k_cat /K_m ) for phenylpyruvate were 1.68 mmol/L, 122.66 s^-1 , and 73.01 (mmol/L)^-1 s^-1 , respectively. This enzyme can catalyze phenylpyruvate and the product presented excellent optical purity (enantioselectivity >99%). The results suggest that LF-d-LDH0653 is a promising biocatalyst for the efficient synthesis of optically pure d-PLA.

PRACTICAL APPLICATION

A novel d-LDH with phenylpyruvate reducing activity has been isolated and identified. It could be used as a reference for improving the production of optically pure d-PLA. d-PLA has a potential for application as antimicrobial an agent in dairy industry and baking industry, pharmaceutical agent in medicine and cosmetics.

Effects of age and season on haematological parameters of donkeys during the rainy and cold-dry seasons

The aim of the study was to investigate the effects of age and season on haematological parameters of donkeys at rest during the rainy and cold-dry seasons. Thirty healthy donkeys divided into three groups based on their age served as the subjects. During each season, blood sample was collected from each donkey thrice, 2 weeks apart, for haematological analysis, and the dry-bulb temperature (DBT), relative humidity (RH) and temperature-humidity index (THI) were obtained thrice each day during the experimental period using standard procedures. During the rainy season, the mean DBT (33.05 ± 0.49 °C), RH (73.63 ± 1.09 %) and THI (84.39 ± 0.71) were higher (P < 0.0001) than the corresponding values of 24.00 ± 0.44 °C, 36.80 ± 0.92 % and 64.80 ± 0.62, during the cold-dry season. Packed cell volume (PCV), erythrocyte count [red blood cell (RBC)], haemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), platelet count (PLT), leucocyte count [white blood cell (WBC)], lymphocyte count (LYM) and neutrophil/lymphocyte ratio (N/L) were higher (P < 0.05) in adults than foals during the rainy season. The MCV, MCH, WBC, NEU, LYM and PLT of adult and yearling donkeys were higher (P < 0.05) during the rainy than the cold-dry season. The PCV, RBC, Hb, MCV, MCH, and NEU of foals were higher in the rainy than the cold-dry season. The N/L of adult and foal donkeys were higher (P < 0.05) in the rainy than in the cold-dry season. In conclusion, PCV, RBC, Hb and LYM were considerably higher in foals than yearlings or adults during the rainy season, while erythrocytic indices and platelet counts were higher in adults or yearlings than in foals in both seasons. Erythrocytic indices, PLT and N/L were higher in the rainy than the cold-dry season in adults, yearlings and foals.

Production of optically pure L-phenyllactic acid by using engineered Escherichia coli coexpressing L-lactate dehydrogenase and formate dehydrogenase

L-Phenyllactic acid (L-PLA) is a novel antiseptic agent with broad and effective antimicrobial activity. In addition, L-PLA has been used for synthesis of poly(phenyllactic acid)s, which exhibits better mechanical properties than poly(lactic acid)s. However, the concentration and optical purity of L-PLA produced by native microbes was rather low. An NAD-dependent L-lactate dehydrogenase (L-nLDH) from Bacillus coagulans NL01 was confirmed to have a good ability to produce L-PLA from phenylpyruvic acid (PPA). In the present study, l-nLDH gene and formate dehydrogenase gene were heterologously coexpressed in Escherichia coli. Through two coupled reactions, 79.6mM l-PLA was produced from 82.8mM PPA in 40min and the enantiomeric excess value of L-PLA was high (>99%). Therefore, this process suggested a promising alternative for the production of chiral l-PLA.

Enhancement of phenyllactic acid biosynthesis by recognition site replacement of D-lactate dehydrogenase from Lactobacillus pentosus

OBJECTIVES

The Tyr52 residue of D-lactate dehydrogenase (D-LDH) from Lactobacillus pentosus was replaced with small hydrophobic residues and overexpressed in E. coli BL21 (DE3) to enhance 3-phenyllactic acid (PLA) synthesis by whole-cell catalyst.

RESULTS

Escherichia coli pET-28a-d-ldh produced 12.2 g PLA l(-1) in 3 h, with a molar conversion rate of 61 %, while E. coli pET-28a-d-ldh (Y52V) produced 15.6 g PLA l(-1), with a molar conversion rate of 77 %. This study demonstrates the feasibility of using engineered E. coli for PLA production from phenylpyruvate (PPA) and showed that site-directed mutagenesis of d-ldh markedly improved PLA yield and substrate conversion rate.

CONCLUSION

This biocatalytic system is a promising platform for PLA production from PPA.

Protected organic Acid blends as an alternative to antibiotics in finishing pigs

A total of 120 finishing pigs ([Yorkshire×Landrace]×Duroc) with an average body weight (BW) of 49.72 ±1.72 kg were used in 12-wk trial to evaluate the effects of protected organic acids on growth performance, nutrient digestibility, fecal micro flora, meat quality and fecal gas emission. Pigs were randomly allotted to one of three dietary treatments (10 replication pens with 4 pigs per pen) in a randomly complete block design based on their initial BW. Each dietary treatment consisted of: Control (CON/basal diet), OA1 (basal diet+0.1% organic acids) and OA2 (basal diet+0.2% organic acids). Dietary treatment with protected organic acid blends linearly improved (p<0.001) average daily gain during 0 to 6 week, 6 to 12 week as well as overall with the increase in their inclusion level in the diet. The dry matter, N, and energy digestibility was higher (linear effect, p<0.001) with the increase in the dose of protected organic acid blends during 12 week. During week 6, a decrease (linear effect, p = 0.01) in fecal ammonia contents was observed with the increase in the level of protected organic acid blends on d 3 and d 5 of fermentation. Moreover, acetic acid emission decreased linearly (p = 0.02) on d7 of fermentation with the increase in the level of protected organic acid blends. During 12 weeks, linear decrease (p<0.001) in fecal ammonia on d 3 and d 5 and acetic acid content on d 5 of fermentation was observed with the increase in the level of protected organic acid blends. Supplementation of protected organic acid blends linearly increased the longissimus muscle area with the increasing concentration of organic acids. Moreover, color of meat increased (linear effect, quadratic effect, p<0.001, p<0.002 respectively) and firmness of meat showed quadratic effect (p = 0.003) with the inclusion of increasing level of protected organic acid in the diet. During the 6 week, increment in the level of protected organic acid blends decreased (linear effect, p = 0.01) Escherichia coli (E. coli) counts and increased (linear effect, p = 0.004) Lactobacillus counts. During 12-wk of experimental trial, feces from pigs fed diet supplemented with organic acid blends showed linear reduction (p<0.001) of E. coli counts and the tendency of linear increase (p = 0.06) in Lactobacillus count with the increase in the level of organic acid blends. In conclusion, 0.2% protected organic acids blends positively affected growth performance, nutrient digestibility, fecal gas emission and meat quality in finishing pigs without any adverse effects on blood parameters.

Evaluation of the effect of low dietary fermentable carbohydrate content on growth performance, nutrient digestibility, blood characteristics, and meat quality in finishing pigs

A total of 96 pigs (49.23±3.20 kg) were used in an 11 wk growth trial to evaluate the effect of fermentable carbohydrate (FC) content on growth performance, apparent total tract digestibility (ATTD) of nutrient, blood profile, and meat quality. The dietary treatments were: i) negative control (NC), basal diet, ii) positive control (PC), NC+antibiotics (positive control diet with 5 ppm flavomycin), iii) PCL, PC-13% lower FC, and iv) NCL, NC-13% lower FC. The growth performance (average daily gain, average daily feed intake, and gain/feed) didn’t differ among treatments through the whole experiment. These pigs fed the PCL diet had the greater (p<0.05) apparent total tract digestibility (ATTD) of dry matter than those from PC and NC treatment at the end of the experiment. No differences were observed in white blood cell (WBC), red blood cell (RBC), and lymphocyte concentration among different treatments. After the feeding period, meat samples were collected from the pigs at slaughter. The pigs in NCL and PCL treatments had greater (p<0.05) backfat thickness and lower lean percentage. The color value of loin was higher (p<0.05) in NCL treatment compared to PCL treatment. Also, the NCL treatment had higher (p<0.05) marbling value than PC treatment. The drip loss was depressed by PCL and NCL treatment comapared to NC treatments. The water holding capacity (WHC) was higher (p<0.05) in NC and PCL treatment. In conclusion, the low FC can improve digestibility and meat quality of finishing pigs.

Effects of dietary Centella asiatica (L.) Urban on growth performance, nutrient digestibility, blood composition in piglets vaccinated with Mycoplasma hyopneumoniae

To investigate the effects of Centella asiatica (L.) on growth performance, nutrient digestibility and blood composition in piglets, 32 nursery pigs were fed 0.0, 0.5, 1.0 and 2.0% dietary C. asiatica (L.) from 15 to 90 kg BW. At 30 kg BW, nutrient digestibility was measured and at 35 kg BW piglets were vaccinated with Mycoplasma hyopneumoniae. Hematological parameters were checked at 40 and 80 kg BW. Compared with the control, growth performance was not affected. The ether extract, ash and calcium digestibility were lower at 0.5%, and dry matter, crude protein, crude fat, phosphorus and energy digestibility were lower at 1.0% (P<0.05). On hematological values, at 40 kg hematocrit, total white blood cells, neutrophils, eosinophils, basophils, monocytes and lymphocytes were higher at the 2.0% level (P<0.05). Most of these values except basophils and monocytes continued until at 80 kg, at which total white blood cells, neutrophils, eosinophils and lymphocytes were higher even at 1.0% (P<0.05); neutrophil-to-lymphocyte ratio tended to be higher at 2.0% (P<0.03). Cholesterol, triglycerides and antibody levels against M. hyopneumoniae did not differ except that at 40 kg the cholesterol of 0.5% was lower (P<0.05) and M. hyopneumoniae-specific antibodies tended to be higher with increasing levels of C. asiatica (L.) (P<0.07). The result that C. asiatica (L.) could not improve growth performance but increased values of serum hematocrit and white blood cells, and mycoplasma immunity to M. hyopneumoniae might suggest that C. asiatica (L.) has no function to elevate body weight but has the potential to enhance innate immunity.

Enzymatic production of D-3-phenyllactic acid by Pediococcus pentosaceus D-lactate dehydrogenase with NADH regeneration by Ogataea parapolymorpha formate dehydrogenase

3-Phenyllactic acid (PLA) is an antimicrobial compound with broad and effective antimicrobial activity against both bacteria and fungi. Enzymatic production of PLA can be carried out from phenylpyruvic acid by lactate dehydrogenase (LDH); however, the enzymatic reaction is accompanied by NADH oxidation that inhibits PLA biotransformation. Here, NADH regeneration was achieved using the formate dehydrogenase from Ogataea parapolymorpha and introduced into the D-PLA production process using the D-LDH from Pediococcus pentosaceus. Optimum PLA production by dual enzyme treatment was at pH 6.0 and 50 °C with both enzymes at 0.4 μM. Using 0.2 mM NADH, D-PLA production by NADH regeneration system reached 5.5 mM, which was significantly higher than that by a single-enzyme reaction.

Isolation and characterization of antifungal compound from Lactobacillus plantarum KCC-10 from forage silage with potential beneficial properties

AIMS

The purpose of this study was to isolate, identify and characterize an antifungal compound from Lactobacillus plantarum KCC-10 from forage silage with potential beneficial properties.

METHODS AND RESULTS

The 16S rRNA gene-based phylogenetic affiliation was determined using bioinformatic tools and identified as Lactobacillus sp. KCC-10 with 100% sequence similarity to L. plantarum. The antifungal substances were extracted with ethyl acetate from spent medium in which Lactobacillus sp. KCC-10 was cultivated. Antifungal activity was assessed using the broth microdilution technique. The compounds were obtained by eluting the crude extract with various concentrations of solvents followed by chromatographic purification. Based on the infrared, (13) C nuclear magnetic resonance (NMR) and (1) H NMR spectral data, the compound was identified as a phenolic-related antibiotic. The minimum inhibitory concentration of the compound against Aspergillus clavatus, A. oryzae, Botrytis elliptica and Scytalidium vaccinii was 2.5 mg ml(-1) and that against A. fumigatus, A. niger and S. fusca was 5.0 mg ml(-1) , respectively. In addition, Lactobacillus sp. KCC-10 was highly sensitive towards oxgall (0.3%) but grew well in the presence of sodium taurocholate (0.3%). An antimicrobial susceptibility pattern was an intrinsic feature of this strain; thus, consumption does not represent a health risk to humans or animals.

CONCLUSION

Novel L. plantarum KCC-10 with antifungal and potential probiotic properties was characterized for use in animal food.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study revealed that L. plantarum KCC-10 exhibited good antifungal activity similar to that of probiotic Lactobacillus strains.

Effects of Bacillus subtilis var. natto and Saccharomyces cerevisiae fermented liquid feed on growth performance, relative organ weight, intestinal microflora, and organ antioxidant status in Landes geese

The aim of this study was to investigate the effect of Bacillus subtilis var. natto N21 (BAC) and Saccharomyces cerevisiae Y10 (SAC) fermented liquid feed (FLF) during different incubation times on the growth performance, relative organ weight, intestinal microflora, and organ antioxidative status in Landes geese. Two hundred forty male Landes geese (10 wk old) with the BW of 4.163 ± 0.108 kg were selected for a 3-wk trial and randomly allotted to 3 treatments according to their BW (10 replicates/treatment and 8 geese/replicate). The treatments included 1) CON, dry basal feed (corn-soybean basal diet mixed with water) before feeding (2:1 wt/wt), 2) FLF24, 24 h FLF, and 3) FLF48, 48 h FLF. The FLF diet was prepared by storing basal diet with 10(9) cfu/g feed of each BAC and SAC and water (2:1 wt/wt) in a closed tank at 20°C fermented for 24 or 48 h. The BW gain and feed intake of geese fed FLF24 and FLF48 was greater (P < 0.05) than CON treatment. Feeding geese with FLF24 and FLF48 feeds increased (P < 0.05) the relative weight of leg muscle whereas the liver was heavier (P < 0.05) in FLF48 treatment than CON and FLF24 treatments. The FLF24 and FLF48 increased (P < 0.05) the Lactobacillus population and depressed (P < 0.05) Escherichia coli population in small and large intestine. The high-density lipoprotein cholesterol concentration was greatest (P < 0.05) in FLF48 whereas the total cholesterol and low-density lipoprotein cholesterol was less (P < 0.05) in FLF24 and FLF48 treatments than CON. Geese fed FLF48 diet had greater glutathione peroxidase activity and less malondialdehyde content in heart and liver than those fed CON diet. In breast muscle, the superoxide dismutase activity were increased (P < 0.05) by FLF24 and FLF48 treatments than CON diet. In conclusion, the results indicated that feeding geese with BAC and SAC mix FLF can improve growth and feed intake, modulate the intestine ecology, and decrease the blood cholesterol concentrations; it also can improve the antioxidative status of organs and breast muscle.

Recent research on 3-phenyllactic acid, a broad-spectrum antimicrobial compound

3-Phenyllactic acid (PLA), which is an organic acid widely existing in honey and lactic acid bacteria fermented food, can be produced by many microorganisms, especially lactic acid bacteria. It was proved as an ideal antimicrobial compound with broad and effective antimicrobial activity against both bacteria and fungi. In addition, it could be used as feed additives to replace antibiotics in livestock feeds. This article presented a review of recent studies on the existing resource, antimicrobial activity, and measurement of PLA. In addition, microorganism strains and dehydrogenases producing PLA were reviewed in detail, the metabolic pathway and regulation of PLA synthesis in LAB strains were discussed, and high-level bioproduction of PLA by microorganism fermentation was also summarized.