Survivability of freeze- and spray-dried probiotics and their effects on the growth and health performance of broilers

Background and Aim: Many strains of probiotics have been exploited and used as animal dietary supplements for broiler production. The efficacy and survival of probiotics during production may reflect better activities of the probiotics in the host. This study investigated the effects of freeze- and spray-drying on the survivability and properties of probiotics and their ability to improve the growth and health performance of broilers. Materials and Methods: Probiotic powders of four strains of lactic acid bacteria, Enterococcus faecium CA4, Enterococcus durans CH33, Ligilactobacillus salivarius CH24, Pediococcus acidilactici SH8, and Bacillus subtilis KKU213, were prepared using rice bran/chitosan/carboxy methyl cellulose as the carrier. The survival of each probiotic strain was investigated under stress conditions, including freeze-drying, spray-drying, and simulated gastrointestinal conditions. The body weight gain (BWG) and intestinal histomorphology were determined to assess broiler growth performance. Results: All dried probiotics yielded a high survival rate during freeze-drying (95.8-98.6%) and spray-drying (94.4-98.2%). In addition, an analysis of the main effect revealed that the effectiveness of freeze-drying was higher than that of spray-drying in minimizing the loss of cell viability. The antimicrobial activity of all immobilized dried probiotic strains against Salmonella was maintained. The immobilized probiotics tolerated a low pH value of 2.0 and 0.5% (w/v) bile salt. Probiotic administration of a mixture of the five dried probiotics to 1-day-old hatched male broilers at early and late ages resulted in potential colonization in the broiler intestine, and enhancements in the BWG, lipid metabolism, and gut health (villus height and cryptal depth) were observed in the probiotic-treated groups. Conclusion: The administration of three doses of the spray-dried probiotic mixture at days 15, 17, and 19 after hatching was sufficient to achieve long-term growth and health benefits in broilers. This finding might provide a cost-effective alternative to the administration of commonly used antibiotics in broiler production

Microarray-based analysis of cadmium-responsive microRNAs in rice (Oryza sativa)

MicroRNAs (miRNAs) are a class of small non-coding RNAs that negatively regulate specific target mRNAs at the post-transcriptional level. Plant miRNAs have been implicated in developmental processes and adaptations to environmental stresses. Cadmium (Cd) is a non-essential heavy metal that is highly toxic to plants. To investigate the responsive functions of miRNAs under Cd stress, miRNA expression in Cd-stressed rice (Oryza sativa) was profiled using a microarray assay. A total of 19 Cd-responsive miRNAs were identified, of which six were further validated experimentally. Target genes were also predicted for these Cd-responsive miRNAs, which encoded transcription factors, and proteins associated with metabolic processes or stress responses. In addition, the mRNA levels of several targets were negatively correlated with the corresponding miRNAs under Cd stress. Promoter analysis showed that metal stress-responsive cis-elements tended to occur more frequently in the promoter regions of Cd-responsive miRNAs. These findings suggested that miRNAs played an important role in Cd tolerance in rice, and highlighted a novel molecular mechanism of heavy metal tolerance in plants

Metal bioremediation by CrMTP4 over-expressing Chlamydomonas reinhardtii in comparison to natural wastewater-tolerant microalgae strains

Metal pollution in freshwater bodies is a long-standing challenge with large expense required to clean-up pollutants such as Cd. There is widespread interest in the potentially low-cost and sustainable use of biological material to perform bioremediation, such as the use of microalgae. Efficient metal bioremediation capacity requires both the ability to tolerate metal stress and metal accumulation. Here, the role of a Chlamydomonas reinhardtii metal tolerance protein (MTP) was examined for enhanced Cd tolerance and uptake. The CrMTP4 gene is a member of the Mn-CDF clade of the cation diffusion facilitator family of metal transporters but is able to provide tolerance and sequestration for Mn and Cd, but not other metals, when expressed in yeast. Over-expression of CrMTP4 in C. reinhardtii yielded a significant increase in tolerance to Cd toxicity and increased Cd accumulation although tolerance to Mn was not increased. In comparison, the metal tolerance of three chlorophyte microalgae strains (Chlorella luteoviridis, Parachlorella hussii, and Parachlorella kessleri) that had previously been adapted to wastewater growth was examined. In comparison to wild type C. reinhardtii, all three natural strains showed significantly increased tolerance to Cd, Cu, Al and Zn, and furthermore their Cd tolerance and uptake was greater than that of the CrMTP4 over-expression strains. Despite CrMTP4 gene over-expression being a successful strategy to enhance the Cd bioremediation potential of a metal-sensitive microalga, a single gene manipulation cannot compete with naturally adapted strain mechanisms that are likely to be multigenic and due in part to oxidative stress tolerance

Role and Regulation of Osmolytes and ABA Interaction in Salt and Drought Stress Tolerance

Abiotic stress conditions lead to the defects in plant growth and development and also reduction in flowering and fertility. Under prolonged stresses, imminent death of the plants has been observed. To cope with such stress conditions, plants accumulate a wide variety of organic solutes called osmolytes. Osmolytes are accumulated in bacteria, lower, and higher plants as a response primarily to abiotic stress. They encompass amino acids such as proline, tertiary sulfonium, and quaternary ammonium compounds like beatines, sugars (trehalose), and polyhydric alcohols (mannitol, sorbitol, pinitol, etc.). Osmolytes are accumulated in the cytoplasm as well as in chloroplasts in certain cases for osmotic adjustment under stress conditions. This enables the plants to absorb water and survive under stress. Out of the many phytohormones that play diverse roles during abiotic stress, abscisic acid (ABA) is an important one and perceived by plants by a core signaling module. As an integral part of signal transduction during stress conditions, ABA and other hormones regulate not only stomatal closure, but also a wide array of gene expressions including osmolyte biosynthetic pathway genes. Many signal molecules like nitric oxide, carbon monoxide, and hydrogen sulfide also play a vital role in osmolyte biosynthesis. Osmolytes appear to have multiple functions during stress such as osmotic adjustment and scavenging of reactive oxygen species (ROS). Thus, generation of ROS and osmolyte accumulation are linked together. This review summarizes the role played by ABA in signal transduction, the role of hormones to regulate osmolyte biosynthesis, and various functions carried out by them

Bacillus subtilis and lactic acid bacteria improve the growth performance and blood parameters and reduce Salmonella infection in broilers

Aim: The aim of the study was to determine the potentials and effects of Bacillus subtilis and lactic acid bacteria (LAB) as probiotics on broiler growth, health, and Salmonella infection. Materials and Methods: To evaluate the inoculum size applicable for broilers, 1-day-old broilers were orally fed fresh cultures of single strains and a B. subtilis KKU213/Pediococcus pentosaceus NP6 mixture at 108 and 1012 colony-forming unit (CFUs)/mL/chick. The body weight gain (BWG), Salmonella contamination level and total Bacillus and LAB abundances in the crop and intestine were measured. Subsequently, 1-day-old broilers were orally fed of KKU213, CH403, and Pediococcus acidilactici SH8 at 1010 CFUs/mL, followed by inulin. After 35 days, the BWG, Bacillus and LAB abundances in the cecum, blood parameters, and KKU213 colonization were assessed. Results: The broilers fed single strains or KKU213+NP6 exhibited a higher BWG and a higher crop LAB abundance than the controls (p<0.05). Probiotic feeding decreased the intestinal Salmonella abundance and correspondingly increased the LAB abundance. The broilers fed the mixed culture (KKU213+CH403+SH8) followed by prebiotics showed lower mortality, higher blood high-density lipoprotein levels, and lower blood uric acid levels than the controls (p<0.0004). Probiotic feeding significantly increased the Bacillus and LAB counts (p<0.05). A CE330 isolate obtained from the cecum after 35 days of KKU213 feeding was closely related to B. subtilis KKU213. Conclusion: B. subtilis KKU213 is a potent probiotic strain that can survive, colonize and reduce Salmonella infection in broilers and improve their growth and health. This strain, combined with different LAB can act synergistically in the gut and promote broiler growth

Reduction of cadmium uptake in rice endophytically colonized with the cadmium-tolerant bacterium Cupriavidus taiwanensis KKU2500-3

The effects of the cadmium (Cd)-tolerant bacterium Cupriavidus taiwanensis KKU2500-3 on the growth, yield and Cd concentration in rice grains were investigated in the rice variety Phitsanulok 2 (PL2), which was cultivated in a hydroponic greenhouse. The numbers of Cd-tolerant bacteria isolated from the roots and shoots of plants under the RB [rice with bacteria] and RBC [rice with bacteria and Cd] treatments ranged from 2.60 to 9.03 and 3.99 to 9.60 log CFU•gThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Prevalence of Antibiotic-resistant Salmonella in Vegetables and Fermented Foods and their Control by Lactic Acid Bacteria

Salmonella is the leading cause of foodborne disease and a public health concern. In this study, food samples were collected from fresh markets within northeastern Thailand. Antibiotic-resistant Salmonella were detected in fresh vegetables and fermented meat products. Of 172 collected food samples, 25 (14.53%) were contaminated with Salmonella resistant to at least 1 of 9 antibiotics. Eight strains of 7 serovars, including S. Derby, S. Paratyphi B, S. Stanley, S. Dabou, S. Rissen, S. Hvittingfoss, and S. Brenderup, were resistant to S, TE, CN, SXT, and NA, accounting for 20%, 16%, 12%, 12%, and 12% of all antibiotics, respectively. To determine the anti-Salmonella activity of lactic acid bacteria, Pediococcus pentosaceus PS34 isolated from fermented fish was selected from 5 strains of food-derived lactic acid bacteria according to the antibacterial and acid-resistance properties. When added to 3 log CFU/ml cultures of Salmonella, the PS34 cell-free supernatant (CFS) reduced the numbers of Salmonella after 1, 15, 30, and 60 minutes of incubation; the reduction reached 99.9% within 30 minutes. The minimal arbitrary inhibition concentration of freeze-dried PS34 CFS was a 1:4 dilution. With the exception of neutralization to pH 6.5, treatment with proteolytic enzymes and heating at 100°C and 120°C did not reduce the freeze-dried PS34 CFS anti-Salmonella activity, indicating that the extracellular PS34 bioactive substances were heat stable and highly effective against Salmonella in vitro. Thus, bioactive substances produced by P. pentosaceus PS34 have the potential to reduce the risk of antibiotic-resistant Salmonella from contaminated food reaching consumers