Growth Promotion Research Articles

Small Regulatory RNAs of the Rsm Clan in Pseudomonas.

Bacteria of the genus Pseudomonas are ubiquitous on Earth due to their great metabolic versatility and adaptation to fluctuating environments and different hosts. Some groups are important animal/human and plant pathogens, whereas others are studied for their biotechnological applications, including bioremediation, biological control of phytopathogens and plant growth promotion. Notably, their adaptability is mediated by various signal transduction systems, with the post-transcriptional Gac-Rsm cascade playing a key role. This pervasive Pseudomonas pathway controls major transitions at the population level, such as motile/sessile lifestyle, primary/secondary metabolism or replicative/infective behaviour. A hallmark of the Gac-Rsm cascade is the participation of small, regulatory, non-coding RNAs of the Rsm clan. These RNAs are synthetised in response to cell-density-dependent autoinducer signals channelled through the GacS/GacA two-component system, and they counteract, by molecular mimicry, the translational control that RNA-binding proteins of the RsmA family exert over hundreds of mRNAs. Rsm RNAs have been investigated in a few Pseudomonas model species, evidencing the presence of a variable number and families of genes depending on the taxonomic clade. However, the global picture of the distribution of these riboregulators at the genus level was unknown until now. We have undertaken a comprehensive survey and annotation of the vast array of gene sequences encoding members of the Rsm RNA clan in 245 complete genomes that cover 28 phylogenomic clades across the entire genus. The properties of the different families of rsm genes, their phylogenetic radiation, as well as the features of their promoters and adjacent regions, are discussed. The novel insights presented in our manuscript will significantly boost research on the biology of these prevalent RNAs in understudied species of the genus Pseudomonas and closely related genera.

Food Additives Derived from Fruits and Vegetables for Sustainable Animal Production and Their Impact in Latin America: An Alternative to the Use of Antibiotics.

The production of healthy animal-derived food entails the effective control of foodborne pathogens and strategies to mitigate microbial threats during rearing. Antibiotics have been traditionally employed in animal farming to manage bacterial infections. However, the prohibition of antibiotic growth promoters in livestock farming has brought significant changes in animal production practices. Although antibiotics are now restricted to treating and preventing bacterial infections, their overuse has caused serious public health issues, including antibiotic resistance and the presence of antibiotic residues in food and wastewater. Therefore, sustainable animal production is crucial in reducing the spread of antibiotic-resistant bacteria. Annually, 40-50% of fruit and vegetable production is discarded worldwide. These discards present significant potential for extracting value-added ingredients, which can reduce costs, decrease waste, and enhance the food economy. This review highlights the negative impacts of antibiotic use in livestock farming and stresses the importance of analyzing the challenges and safety concerns of extracting value-added ingredients from fruit and vegetable co-products at an industrial scale. It also explores the current trends in reducing antibiotic use in livestock, with a focus on Latin American contexts. Finally, the suitability of using value-added ingredients derived from fruit and vegetable co-products for animal feeds is also discussed.

Wood- and Manure-Derived Biochars Reduce Antibiotic Residues and Shift Antibiotic Resistance Genes and Microbial Communities in Manure Applied Forage–Soil Systems

The increasing use of antibiotics in livestock poses environmental risks, leading to contamination of agricultural soils and propagation of microbial antibiotic-resistant genes (ARGs). This study examined the impacts of wood- and manure-derived biochar (BC) on antibiotic residues, ARGs, and microbial communities in sandy loam and clay loam soils amended with manure in Cynodon dactylon pastures. We hypothesized that BC amendments would influence the degradation of antibiotics and the structure of microbial communities based on their physicochemical properties and soil types. Our results demonstrated that wood BC reduced the concentrations of tetracycline and sulfonamides, particularly in sandy loam soil, due to its larger surface area and hydrophobic properties. In contrast, manure BC provided additional nutrients and supported atmospheric nitrogen-fixing microbial groups, especially in clay loam soil, while exhibiting variable efficiency in reducing antibiotic residues due to its lower surface area and higher ash content. These findings underscore the differential impacts of each BC type, emphasizing the need for tailored BC applications based on soil type to effectively mitigate antibiotic contamination and promote sustainable agricultural practices. In conclusion, wood BC was more effective in enhancing soil health by reducing antibiotic residues and improving microbial diversity, particularly in sandy loam soils, while manure BC was beneficial for nutrient cycling in clay loam soils.

Management of Rhizoctonia blight of groundnut using antagonistic effects of bioagents and organic amendments

Rhizoctonia blight disease caused by Rhizoctonia solani in groundnut crop is one of the most devastating diseases occurring worldwide. The disease affects the morphological and physiological parameters of the crop leading to reduction in pod yield as well as oil yield. The pathogen was isolated locally and identified as Rhizoctonia solani based on molecular characterization. The efficacy of different bioagents in reducing the radial growth of pathogen was tested in vitro and highest mycelia growth inhibition was recorded by Trichoderma asperellum (89.07 %). Among the fungicides tested, 100 % mycelial growth inhibition was observed by use of Carbendazim 50 WP, Tebuconazole 25.9 % EC, Hexaconazole 5 % suspension concentrate (SC) and Tebuconazole 50 % + Trifloxystrobin 25 % water-dispersible granule (WG). Among different organic substances tested in vitro, neem seed cake achieved maximum mycelial growth inhibition of 50.74 % and 54.08 % at 10 % and 20 % concentrations respectively. In the field experiment, treatment with application of neem seed cake to the soil at 500 kg/ha + application of mustard seed cake to the soil at 500 kg/ha + treatment of seeds with Tebuconazole at 1.5 g/kg of seed + treatment of seeds with T. asperellum at 10 g/kg of seed was found to be the best in enhancing plant health, growth promotion and oil yield. The combined treatment of bioagent, fungicide and organic amendment recorded maximum number of branches (14.00), number of leaves (668.33), plant dry weight (64.17 g), 100 pod weight (65.00 g) and oil yield (47.33 %) compared to the control and other treatments along with reduction of the disease (59.61 %). In the physiological parameters study, the same treatment also recorded maximum pigment contents viz. Chlorophyll a (1.843 mg/g), Chlorophyll b (0.555 mg/g), total chlorophyll (2.397 mg/g) and carotenoid content (0.084 mg/g) but with minimum phenol content (1.693 mg/g). Thus, it can be concluded that integration of selective inputs in the combined treatment of Neem seed cake, Mustard seed cake, Tebuconazole and T. asperellum could enhance the plant health, morphological growth and physiological parameters and increased the oil yield in groundnut along with reduction of the disease.

Bioinoculation Strategies for Enhanced Growth and Development of Economically Important Dalbergia latifolia Roxb

The present experiment was conducted to evaluate the plant growth properties of the native rhizospheric microflora of Dalbergia latifolia, an important medicinal, timber and biofuel plant. A systemic isolation, characterization and identification of rhizospheric soil, collected indigenously, initially produced 45 numbers of fungi and 3 numbers of bacteria. Both groups of organisms were characterized for their extracellular useful activity, especially phosphate solubilisation potential, and presented in terms of solubilisation index and solubilisation efficiency. Two fungi and two bacteria with good phosphate solubilization activity, along with NPK and organic manure, were selected and used in a pot culture experiment to promote the growth and development of Dalbergia latifolia under nursery conditions. Data recorded on 90 Days of plant growth exhibited the growth promotion of inoculated plants over control uninoculated experimental set. Results obtained on morphological and physiological growth parameters exhibited that the application of Aspergillus flavus followed by Burkholderia territorii + org. manure showed maximum shoot height and inoculation of Burkholderia anthina + Aspergillus sp. + NPK was significantly higher leaf area. Significantly longer root has been observed in Burkholderia territorii. However, a difference was observed in the number of leaves in Aspergillus flavus. + Org. manure and higher numbers of branches were observed in Aspergillus flavus only as compared to uninoculated control. Coinoculation of Aspergillus flavus + Penicillium simplicissimum showed better performance in fresh and dry shoot biomass as compared to other treatments. Burkholderia territorii + Org.manure produced higher fresh biomass of roots and coinoculation of bacteria Burkholderia territorii + Burkholderia anthina helped in enhancing root dry biomass. Dual inoculation of Aspergillus flavus + Penicillium simplicissimum gives better result in both fresh biomass of leaves and dry biomass of leaves. Application of Aspergillus flavus + Penicillium simplicissimum enhanced the total fresh biomass of the seedlings whereas supplementation of Burkholderia anthina + Penicillium simplicissimum enhanced the total dry biomass. Coinoculation of Aspergillus flavus + Penicillium simplicissimum showed higher RGR and coinoculation of Burkholderia anthina + Aspergillus flavus + NPK showed quite higher Leaf area ratio (LAR cm2gm-1). Co inoculation of Burkholderia territorii + Burkholderia anthina + Organic Manure showed highest root-shoot ratio and Coinoculation of Penicillium simplicissimum + Org. manure showed higher Net assimilation rate (NAR). However, Bacterial and fungal inoculants were also used as potent bioinoculants for the growth and establishment of crops of forest tree species.

PSI-25 Improvements in the jejunal villus morphometry and increases in the number of goblet cells with the addition of humic substances from vermicompost in weaned pigs

Abstract An experiment was carried out with the objective of evaluating the effects of the addition of humic substances (HS) from vermicompost in the feed on the histology measurements and number of goblet cells in the jejunal villus in piglets at weaning. Piglets (n = 200) were housed in groups of five in elevated pens and were assigned to one of four treatments: 1 = Positive control diet (PC) with antibiotic growth promoter (AGP), 2 = Negative control diet (NC) without AGP, 3 and 4 = Diets without AGP added with 2500 and 5000 ppm HS, respectively. HS were extracted from a vermicompost made of sheep and pig manure using an alkaline solution and added in dry form to the feed. A basal sample of 5 cm of jejunum was taken from 10 piglets at weaning; the same was done on d 3 and 7 post-weaning, selecting 5 piglets per treatment. The samples were processed to apply different stains: () eosin and hematoxylin for morphometric analysis: villus height, villus thickness, villus area, crypt depth and the villus eight to crypt depth ratio; 2) Pass Schiff to quantify neutral goblet cells; 3) Alcian Blue pH 1.0 for heavily sulfated goblet cells; and 4) Alcian Blue pH 2.5 for non-sulfated acid goblet cells. Ten villi per animal were evaluated. Images were analyzed with Leica interactive measurement software. The results were subjected to ANOVA in a randomized complete block design. Regarding the histology of villus in the jejunum, on d 3 post-weaning the pigs added with HS had a greater villus height (3 = 317.75, 4 = 310.46 vs 2 = 278.08 and 1 = 307.12 µm; P < 0.05; SEM = 10.86), villus width (3 = 94.64, 4 = 95.04 vs 2 = 85.39, and 1 = 93.51 µm; P < 0.01; SEM = 2.32); and villus area (3 = 95841, 4 = 93678 Vs 2 = 76646 and 1 = 93471 µm2; P < 0.01; SEM = 4343), compared with the NC. The crypt depth was greater in piglets added with HS (3 = 236.78, 4 = 241.85 vs 1 = 194.65 and 2 = 203.01 µm; P < 0.01; SEM = 6.57) compared with the PC and NC. On d 7 postweaning, the piglets added with HS showed greater villus height (3 = 293.24, 4 = 282.45 vs 1 = 258.95 and 2 = 253.03 µm; P < 0.01; SEM = 7.89); villus area (3 = 101354, 4 = 94,575 vs 1 = 85,633 and 2 = 82,125 µm2; P < 0.01; SEM = 3818) and crypt depth (3 = 326.82, 4 = 337.28 vs 2 = 283.88 and 1 = 321.53 µm; P < 0.01; SEM = 8.285) compared with the PC and NC. The number of neutral, heavily sulfated and non-sulfated goblet cells at 3 and 7 d post-weaning were significantly reduced in all treatments compared with weaning; but with the addition of HS a greater number (P < 0.05) of goblet cells per villus were shown. The results suggest that HS from vermicompost improves the intestinal morphometry and increases the number of goblet cells that produce protective intestinal mucus at 3 and 7 d post-weaning in pigs.

Colombian cyanobacteria with cytotoxic activity in cancer cell lines

In the last decade, cyanobacteria have emerged as significant reservoirs of bioactive molecule for the pharmaceutical, cosmetic, and alimentary industries, given the wide spectrum of new possibilities of different organic pigments, proteins, carbohydrates, lipids, and powerful antioxidant sources for specific and stronger cancer treatments, autoimmune syndromes, obesity, and inflammatory diseases. A bioactivity screening was executed for 12 strains of Colombian cyanobacteria (10 marine and 2 freshwater) representative of the orders present in the LAUN culture collection, performing methanol extracts per sample, which was fractionated by reverse phase HPLC protocol, obtaining 8 fractions for each crude extract. All these crude extracts were tested for antimicrobial activities through disk diffusion methodology, and fractions were tested for cytotoxic activity against cancer cell lines by cell viability detection with MTT. Cyanobacteria's extracts showed considerable cytotoxic activity for osteosarcoma (MG063) and colon cancer (HCT116) cell lines (61 and 66 % of reduced viability compared to untreated controls, respectively) and a surprising cell growth promotion for the control group fibroblast (3T3L1) and brain endothelial (HCMEC) cell lines (121 and 127 % growth, respectively), no bioactivity was observed in the antimicrobial tests. These findings underscore the expansive cytotoxic potential of Colombian cyanobacteria against cancer cell lines and, notably, their growth-promoting effects on healthy cell lines. This positions them as promising sources of bioactive compounds for future pharmaceutical developments.

PSI-23 Growth implants can decrease enteric methane emissions intensity from finishing beef cattle

Abstract Growth promotants are a useful tool in cattle production to improve their environmental impact by decreasing emissions per unit of gain and increasing overall feed efficiency. The objective of this study was to assess the relationship between enteric methane emissions, feed intake, average daily gain (ADG), and feed efficiency of implanted and nonimplanted finishing steers. Cattle (n = 62) were housed at the Climate Smart Research pens at Colorado State University and blocked by body weight (BW) into two pens and randomly assigned to treatment. Each pen was equipped with GreenFeed automated head chambers and SmartFeed feed intake measurement (C-Lock, Rapids City, SD). The study was a completely randomized block design. Animals within each block were then randomly assigned a treatment: implanted with Component TE200 (IMP; Elanco Animal Health, Greenfield, IN) or not implanted (CON). Enteric emissions, dry matter feed intake, BW, and BW gain (ADG) were collected from each individual animal from the light and heavy blocks for 80 and 52 d, respectively. Data were analyzed in JMP Pro with the linear model function and significance was declared a P ≤ 0.05. IMP cattle had a greater average ADG (2.40 kg/d vs 1.77 kg/d, P < 0.0001) compared with CON cattle. A difference was observed in total methane (CH4) emissions between treatments (200.83 g CH4/d IMP and 187.45 g CH4/d CON, P = 0.02). Dry matter intake (DMI) was not different between treatments (P = 0.17). Methane emissions intensity for each treatment was 84.89 (IMP) and 106.90 g/kg of ADG (CON) was different (P = 0.0002), while CH4 yield (CH4 per kg of DMI) was not different (P = 0.12). Overall feed efficiency between treatments resulted in IMP animals having a greater feed efficiency (4.74 kg DM/kg ADG) compared with CON animals (6.32 kg DM/kg ADG, P < 0.0001). In summary, growth promotants decrease CH4 emissions intensity in finishing steers and increase animal feed efficiency without affecting daily DMI.

PSLBI-8 Effect of sunflower (Tithonic diversifolia) extract on growth performance and serum antioxidant enzymes of broiler chickens

Abstract The ban of antibiotic growth promoters in many countries has increased the use of plant bioactives as alternatives to antibiotics; however, there is little information on the impact of sunflower extract on animal performance. Therefore, this study focused on the use of sunflower extract on growth performance and serum antioxidant enzymes of broiler chickens. Unsexed broiler chicks (n = 128; 1 d of age) were completely randomized into group 1 (Con: 0 mL of extract; n = 32), group 2 (2SE: 2mL/L of extract, n = 32), group 3 (4SE: 2mL/L of extract; n = 32) and group 4 (6SE: 2mL/L of extract; n = 32). Each group was replicated 4 times with 8 chicks per replicate. Data was analyzed as one-way ANOVA using SAS 9.4 at 5% alpha. There was no significant (P = 0.0605) difference in final body weight (BW), BW gain (P = 0.0557) and average daily gain of the chickens. The BW gain was 1,727.54g, 1,970.87g, 1,913.86 g and 1,765.53 g for CON, 2SE, 4SE and 6SE respectively. There was significant (P < 0.05) difference in superoxide dismutase and glutathione peroxidase while no significant difference was observed in catalase enzyme activity. In conclusion, sunflower extract could increase the antioxidant status of broiler chickens by scavenging free radicals, it has the potential to increase growth performance, thereby increasing broiler productivity and welfare.

Profiling Metabolites with Antifungal Activities from Endophytic Plant-Beneficial Strains of Pseudomonas chlororaphis Isolated from Chamaecytisus albus (Hack.) Rothm.

Fungal phytopathogens represent a large and economically significant challenge to food production worldwide. Thus, the application of biocontrol agents can be an alternative. In the present study, we carried out biological, metabolomic, and genetic analyses of three endophytic isolates from nodules of Chamaecytisus albus, classified as Pseudomonas chlororaphis acting as antifungal agents. The efficiency of production of their diffusible and volatile antifungal compounds (VOCs) was verified in antagonistic assays with the use of soil-borne phytopathogens: B. cinerea, F. oxysporum, and S. sclerotiorum. Diffusible metabolites were identified using chromatographic and spectrometric analyses (HPTLC, GC-MS, and LC-MS/MS). The phzF, phzO, and prnC genes in the genomes of bacterial strains were confirmed by PCR. In turn, the plant growth promotion (PGP) properties (production of HCN, auxins, siderophores, and hydrolytic enzymes, phosphate solubilization) of pseudomonads were bioassayed. The data analysis showed that all tested strains have broad-range antifungal activity with varying degrees of antagonism. The most abundant bioactive compounds were phenazine derivatives: phenazine-1-carboxylic acid (PCA), 2-hydroxy-phenazine, and diketopiperazine derivatives as well as ortho-dialkyl-aromatic acids, pyrrolnitrin, siderophores, and HCN. The results indicate that the tested P. chlororaphis isolates exhibit characteristics of biocontrol organisms; therefore, they have potential to be used in sustainable agriculture and as commercial postharvest fungicides to be used in fruits and vegetables.

PSVI-26 The benefits of probiotics (L. plantarum and L. acidophilus) supplement in growth performance, egg production, gas emission and gut microbiome diversity in Hy-Line brown laying hens

Abstract During the past few decades, antibiotics have been widely used at subtherapeutic doses to improve growth rates and performance in the poultry industry. However, antibiotics can result in side effects including bacterial resistance; these side effects often have detrimental consequences for human health. Thus, the poultry sector was urged to seek alternative strategies to promote animal performance. One environmentally friendly approach to growth promotion involves the use of probiotics, which have been used in the poultry industry for decades. Therefore, we aimed to investigate the effects of dietary supplementation with Lactobacillus spp. (L. plantarum and L. acidophilus) on growth performance, egg production, gas emission and gut microbiota diversity in laying hens. A total of 192 Hy-Line brown laying hens were randomly divided into four groups and assigned to one of four dietary treatments for 12 wk. The test treatments were basal diet (TRT1), basal + 0.25% antibiotic (TRT2), and basal + 0.1% probiotics (TRT3), and basal + 0.2% probiotics (TRT4). Laying hens fed a diet supplemented with 0.2% probiotics showed increased (P < 0.05) egg production in wk 9, 10, and 12. Moreover, fecal ammonia and hydrogen sulfide emissions were reduced (P < 0.05) in the probiotic groups. Microbiome analysis showed increased (P < 0.05) species richness in the probiotic groups, as indicated by Chao1 and Shannon indices, but a decrease (P < 0.05) in species diversity according to the Simpson index, suggesting a specific microbial community development due to probiotic supplementation. In conclusion, this study provides us with an insight into the potential use Lactobacillus spp. probiotic as a food supplement in the laying hen industry also provides us with a better understanding of the interplay between Lactobacillus spp. and the gut microbiome diversity in laying hens.

Evaluation of 1021Bp, a close relative of Pseudomonas eucalypticola, for potential of plant growth promotion, fungal pathogen suppression and boxwood blight control

BackgroundPseudomonas eucalypticola, a new species of the P. fluorescens group that generates most Pseudomonas-based biocontrol agents, has not been found in any plants other than Eucalyptus dunnii leaves. Except for antagonism to the growth of a few fungi, its features in plant growth promotion and disease control have not been evaluated. Here, we identified a similar species of P. eucalypticola, 1021Bp, from endophyte cultures of healthy leaves of English boxwood (Buxus sempervirens ‘Suffruticosa’) and investigated its antifungal activity, plant growth promotion traits, and potential for boxwood blight control.ResultsColorimetric or plate assays showed the properties of 1021Bp in nitrogen fixation, phosphate solubilization, and production of indole-3-acetic acid (IAA) and siderophores, as well as the growth suppression of all five plant fungal pathogens, including causal agents of widespread plant diseases, gray mold, and anthracnose. Boxwood plant leaves received 87.4% and 65.8% protection from infection when sprayed with cell-free cultural supernatant (CFS) but not the resuspended bacterial cells at 108–9/mL of 1021Bp at one and seven days before inoculation (dbi) with boxwood blight pathogen, Calonectria pseudonaviculata, at 5 × 104 spores/mL. They also received similarly high protection with the 1021Bp cell culture without separation of cells and CFS at 14 dbi (67.5%), suggesting a key role of 1021Bp metabolites in disease control.ConclusionsGiven the features of plant growth and health and its similarity to P. eucalypticola with the P. fluorescens lineage, 1021Bp has great potential to be developed as a safe and environmentally friendly biofungicide and biofertilizer. However, its metabolites are the major contributors to 1021Bp activity for plant growth and health. Application with the bacterial cells alone, especially with nonionic surfactants, may result in poor performance unless survival conditions are present.

464 Awardee Talk: Gastrointestinal tract physiology in young pigs

Abstract It is indeed a great privilege to have been awarded the 2024 American Feed Industry Association Award in Nonruminant Nutrition Research. I am honored to follow in the footsteps of many great non-ruminant nutritionists in the industry. I commenced my career in the pork industry with a PhD in digestive nutritional physiology focusing on the newly weaned piglet that, some 35 yr later, is still the subject of significant interest amongst researchers, veterinarians and practitioners, and producers alike. My research was amongst the first to demonstrate direct relationships between voluntary feed intake after weaning and structure and function of the small intestine, corresponding to production consequences. To circumvent intestinal tract disturbances after weaning, antibiotic growth promotors (AGPs)/prophylactic levels of antibiotics and mineral compounds (e.g., ZnO) were routinely included in diets. With the withdrawal of AGPs and in some jurisdictions, in-feed medications and ZnO, the commercial importance of maximizing feed intake in the post-weaning period, with appropriate inclusion of fiber and selected feed additives, has become even more apparent. Some of the more recent work I have been involved in, still involving the gastrointestinal tract, has explored the interrelationships as to why progeny born to first-litter sows perform worse than progeny born to multiparous sows. This is a global issue for the pork industry, especially in view of increasing litter size, yet remains one that has been relatively underexplored. A series of Australian studies using primiparous and multiparous sows, and their progeny conducted on commercial farms confirmed these findings, and reported some significant physiological, immunological, and anatomical differences between piglets born to different parity mothers. Piglets born to first-litter sows are born and weaned lighter than their counterparts born to older sows, suggesting they suffer poorer acquisition of maternal immunity and delays in intestinal tract development and skeletal muscle both in utero and soon after birth, and around weaning. Piglets born to first-litter sows enter weaning with reduced intestinal tract integrity and show some signs of reduced immunocompetence, which taken together, may impede their ability to cope with the stressors of weaning. Weaned piglets are typically treated collectively and are not managed by parity, but lifelong consequences of being born to a first-litter sow suggests further work needs to be done in this field. Gastrointestinal tract structure and function in piglets, and indeed in all neonates, is intricately associated with ‘gut health’, which was a term not even in the lexicon of the pork industry when I began my career. It is pleasing to see that the study of the gastrointestinal tract continues today, stronger than ever, as advances in science and methodologies allow for greater introspection of this organ and its multi-directional influences on the biology of the pig.

Biocontrol of fungal pathogens and growth promotion in the Korean fir (Abies koreana E.H.Wilson) seedling using Bacillus velezensis CE 100

The restoration of the endangered Korean fir (Abies koreana E.H.Wilson) forests requires mass production of high-quality and well-developed seedlings for outplanting. However, phytopathogenic fungal infections lower the survival rate and growth vigor of A. koreana seedlings, frustrating the re-afforestation efforts. This study isolated and identified the phytopathogenic fungi causing seedling blight and wilt diseases in A. koreana seedlings and investigated the potential of Bacillus velezensis CE 100 in controlling the fungal pathogens and promoting seedling growth. Phomopsis mali and Fusarium oxysporum were confirmed as the causal agents of blight and wilt diseases, respectively, and both fungi reduced the survival rate of A. koreana seedlings. B. velezensis CE 100 produced cell wall-degrading enzymes: chitinase, protease, and β-1,3-glucanase, and the bacterial crude enzyme fraction inhibited the spore germination and mycelial growth of P. mali and F. oxysporum in a concentration-dependent manner, causing severe morphological deformations. Consequently, treatment with B. velezensis CE 100 improved the survival rate of seedlings infected with either P. mali or F. oxysporum compared to the control and PB media treatment. The bacterium also increased nutrient availability through ammonia–nitrogen production and phosphate solubilization and produced indole-3-acetic acid (IAA), and its inoculation remarkably improved seedling growth (root and shoot dry weight) compared to the control and PB media treatment group. This is the first study to report P. mali and F. oxysporum as the pathogens causing seedling blight and wilt diseases in A. koreana nursery seedling, and the possibility of using B. velezensis CE 100 to control the fungal pathogens and improve the seedling growth without chemical use.

46 Feeding the weaned pig gut and beyond with non-nutritional additives

Abstract Weaning imposes simultaneous stress, resulting in reduced growth performance, increased susceptibility to diseases, and increased morbidity and mortality in weaned pigs. Weaning stress can induce negative changes in the intestine, including damaged intestinal integrity, disturbed digestive and absorptive capacity, increased intestinal oxidative stress, and microbial dysbiosis. Improving intestinal development and health is critically important for enhancing disease resistance and overall health of weaned pigs. This, in turn, can increase their survival rate during this vulnerable stage and improve their productive performance in later stages. A healthy gut may include, but is not limited to, several important features: a healthy proliferation of intestinal epithelial cells, an integrated gut barrier function, a preferable or balanced gut microbiota, and well-developed intestinal mucosa immunity. Burgeoning evidence suggests that many non-nutritional additives can enhance overall intestinal health and beyond by targeting one or several functions of the gut. However, the exact protective mechanisms may vary and are still not completely understood. For example, direct-fed microbials may confer health benefits on the host by producing antimicrobial products, regulating gut microbial profile or immunity, and/or enhancing gut barrier function. Non-digestible carbohydrates and prebiotics exhibit striking impacts on reshaping the composition of gut microbiota in the host by boosting the production of health-promoting bacteria. Phytochemicals, a large variety of secondary plant metabolites, have been known for their broad and promising biological properties, including anti-microbial, antioxidant, and immune-modulating activities. Several short chain fatty acids derivatives aim to target the upper gastrointestinal tract, where the major nutrients are digested and absorbed, to promote intestinal health of pigs. Moreover, butyrate and valerate glycerides exhibit strong in vitro antimicrobial effects against enterotoxigenic Escherichia coli F18, one of the dominant pathogens causing post-weaning diarrhea globally. There are more candidates in the list that have been used in weaned pigs and shown promising results on growth and health promotion. Therefore, increasing our current understanding of non-nutritional additives and their influences on intestinal function during weaning will facilitate the development of more dietary strategies that increase stress resilience of weaned pigs.

Mechanistic insights to Paenibacillus lentimorbus mediated biocontrol of Alternaria solani in Solanum lycopersicum L. through carbohydrate reallocation and sweet immunity suppression

Researchers envisaged that PGPR (plant growth promoting rhizobacteria) has vast possibilities as a bioinoculant that will lead to revolution. However, it's still very far from becoming commercially successful. Here, the information regarding the root colonization of PGPR in host plants and plant response towards PGPR is inadequate. It can provide valuable information for developing successful biofertilizers and biocontrol agents. PGPR (Paenibacillus lentimorbus NRRL B-30488 or CHM12) has been previously reported as a successful commercial biofertilizer and biocontrol agent. However, the exact mechanism of plant growth promotion and biocontrol is poorly studied. So, CHM12 was appraised for biotic stress amelioration of pathogen Alternaria solani in Tomato (Solanum lycopersicum L.) var. S-22 plants. PGPR CHM12 was assessed for various plant growth parameters such as proline, sugar content, etc. in pathogen A. solani (AS) challenged plants and compared with the CHM12 treated plants in a greenhouse study. Then, the metabolomics tool (GC-MS) was used to identify metabolites and their respective genes playing pivotal roles in colonization tactics availed by PGPR. Further, gene expression analysis was done to affirm the involvement of various genes related to metabolites providing biotic stress tolerance in Tomato plants. The current research discerned that PGPR CHM12 revealed significant differences in different plant growth parameters studied. There were 33 distinct metabolites identified, which stipulated the involvement of carbohydrate metabolism mainly in combating biotic stress in this study. Thus, our study reconfirmed very few reported previous results through gene expression analysis, suggesting the downregulation of carbohydrate metabolism genes in PGPR-treated plants. This downregulation of carbohydrate genes might be the critical factor for suppressing the plant's immune response to gaining entry inside the host plant. This also helps in retaining and reallocating carbohydrates in plant cells to reduce pathogen proliferation.

Tapping into haloalkaliphilic bacteria for sustainable agriculture in treated wastewater: insights into genomic fitness and environmental adaptation.

The increasing salinity and alkalinity of soils pose a global challenge, particularly in arid regions such as Tunisia, where about 50% of lands are sensitive to soil salinization. Anthropogenic activities, including the use of treated wastewater (TWW) for irrigation, exacerbate these issues. Haloalkaliphilic bacteria, adapted to TWW conditions and exhibiting plant-growth promotion (PGP) and biocontrol traits, could offer solutions. In this study, 24 haloalkaliphilic bacterial strains were isolated from rhizosphere sample of olive tree irrigated with TWW for more than 20years. The bacterial identification using 16S rRNA gene sequencing showed that the haloalkaliphilic isolates, capable of thriving in high salinity and alkaline pH, were primarily affiliated to Bacillota (Oceanobacillus and Staphylococcus). Notably, these strains exhibited biofertilization and enzyme production under both normal and saline conditions. Traits such as phosphate solubilization, and the production of exopolysaccharide, siderophore, ammonia, and hydrogen cyanide were observed. The strains also demonstrated enzymatic activities, including protease, amylase, and esterase. Four selected haloalkaliphilic PGPR strains displayed antifungal activity against Alternaria terricola, with three showing tolerances to heavy metals and pesticides. The strain Oceanobacillus picturea M4W.A2 was selected for genome sequencing. Phylogenomic analyses indicated that the extreme environmental conditions probably influenced the development of specific adaptations in M4W.A2 strain, differentiating it from other Oceanobacillus picturae strains. The presence of the key genes associated with plant growth promotion, osmotic and oxidative stress tolerance, antibiotic and heavy metals resistance hinted the functional capabilities might help the strain M4W.A2 to thrive in TWW-irrigated soils. By demonstrating this connection, we aim to improve our understanding of genomic fitness to stressed environments. Moreover, the identification of gene duplication and horizontal gene transfer events through mobile genetic elements allow the comprehension of these adaptation dynamics. This study reveals that haloalkaliphilc bacteria from TWW-irrigated rhizosphere exhibit plant-growth promotion and biocontrol traits, with genomic adaptations enabling their survival in high salinity and alkaline conditions, offering potential solutions for soil salinization issues.

48 Dietary functional fiber properties for improved health and disease outcomes in pigs

Abstract In swine production, using feed antibiotics as antimicrobial growth promotants has been reduced; thus, feed alternatives to manage gut health are required. Dietary fiber and similar carbohydrate structures such as resistant starch, oligosaccharides, and exopolysaccharides are nutritional tools that may enhance gut health in pigs. Dietary fiber may have a role to alleviate diarrheal diseases including in pigs post-weaning but can also reduce constipation in sows, but specific functionality depends on fiber properties. Antibiotics are hypothesized to influence gut health via modulation of intestinal microbial profiles; fermentation and intestinal inflammation are considered important mechanisms. Dietary fiber sources differ in a key functional property: fermentability. Rapid fermentation of fiber and oligosaccharides is associated with changes in microbial profiles and increased metabolite production. Recently, microbial composition was hypothesized to be less important and combined output of metabolites should be the focus. Fiber properties may also manipulate retention time and physico-chemical properties of the undigested residue; hence, non-fermentable fiber may prevent constipation in sows. The fiber-like structure resistant starch is not digested and acts as fermentable fiber but has unique properties, because it specifically increases intestinal abundance of bifidobacteria, which are associated with improved gut health. Using crop breeding, feed processing, and feed additives, the structure of fiber and starch can be altered thereby changing its degradation kinetics and affecting its prebiotic activity. Finally, fiber-like structures such as exopolysaccharides from Limosilactobacillus reuteri and unique oligosaccharides may serve as receptor analogues for pathogenic bacteria, e.g., enterotoxigenic Escherichia coli (ETEC). These receptor analogues block lectin domains of bacterial adhesins and thus prevent adherence of pathogens to the gut wall, thereby avoiding initiation of post-weaning diarrhea. In conclusion, dietary fiber and similar structures possess important functional properties that may also provide important solutions to maintain gut health in pigs.

Evaluation of Bacillus velezensis F9 for Cucumber Growth Promotion and Suppression of Fusarium wilt Disease.

Cucumber wilt, caused by Fusarium oxysporum f. sp. cucumerinum (FOC), is a soilborne disease that poses a significant threat to cucumber production, resulting in substantial yield losses. This study aimed to evaluate the biocontrol and growth-promoting effects of Bacillus velezensis, a highly active bacterial strain. In vitro assays revealed that B. velezensis F9 exhibited broad-spectrum antifungal activity against eight plant pathogenic fungi, with inhibition ratio ranging from 62.66% to 88.18%. Additionally, the strain displayed the ability to produce IAA (5.97 ± 1.75 µg/mL), fix nitrogen, produce siderophores, and form biofilms. In vitro growth promotion assays demonstrated that different concentrations of B. velezensis F9 significantly promoted cucumber seedling growth. Furthermore, two pot experiments revealed that the strain exhibited biocontrol efficacy against cucumber wilt, with disease control rates ranging from 42.86% to 67.78%. Notably, the strain significantly increased the plant height, fresh weight, and dry weight, with increases ranging from 20.67% to 60.04%, 40.27% to 75.51%, and 22.07% to 52.54%, respectively. Two field trials confirmed the efficacy of B. velezensis F9 in controlling cucumber wilt, with disease control rates of 44.95% and 33.99%, respectively. The strain effectively alleviated the dwarfing and wilting symptoms caused by the pathogen. Compared with the FOC treatment, the F9 + FOC treatment significantly increased the plant height, fresh weight, and dry weight, with increases of 43.85% and 56.28%, 49.49% and 23.70%, and 36.25% and 73.63%, respectively. Enzyme activity assays indicated that inoculation significantly increased SOD activity in cucumber leaves and neutral phosphatase, sucrase, and urease activity in rhizosphere soil. Correlation analysis revealed a negative correlation between the disease index and plant height, fresh weight, dry weight, and peroxidase activity, with correlation coefficients of -0.53, -0.60, -0.38, and -0.45, respectively. These findings suggest that plant height, fresh weight, and dry weight are significantly negatively correlated with the cucumber disease index, highlighting their importance as indicators for evaluating the biocontrol efficacy of B. velezensis F9. In conclusion, B. velezensis F9 is a highly effective plant growth-promoting rhizobacterium with excellent biocontrol potential, showcasing promising applications in agricultural production.

The role of conservation agriculture in enhancing biodiversity and common beans productivity

Conservation of biodiversity in agricultural landscapes is vital for maintaining ecosystem stability and resilience. Conservation agriculture, a sustainable farming approach that involves minimum tillage and reduced use of synthetic pesticides, herbicides, and growth promoters, has gained attention as a potential strategy to enhance biodiversity and reduce production costs. This study investigated the role of conservation agriculture in enhancing biodiversity and common bean productivity in Tanzania. The study compared plots practicing conservation agriculture (minimum tillage and reduced agrochemical use) with those using conventional farming methods. Biodiversity metrics, that is, earthworm populations, bird species richness, bird nest abundance, bird species diversity, bee visitation rates, and bean yield were assessed. The results showed significant positive effects of conservation agriculture on biodiversity, emphasizing its potential role in promoting sustainable agriculture, biodiversity conservation, and household improvement due to reduced production costs and increased yield per unit area. Earthworms per meter square observed to increase from 12 in the non-conservation plots to 34 in the conservation plots, which is likely to improve nutrient cycling and productivity. Furthermore, conservation plots had a higher number of bird species flying around (36−76) compared with 14–32 in non-conservation plots (4000 m2) at 50 % bean flowering. The number of bird nests observed in the two plots during bean harvesting varied significantly (P<0.05), where the number of bird nests observed in 4000 m2 of non-conservation plots ranged from 14 to 36, compared to 12–62 in conservation plots. High bird nest numbers in conservation plots indicated higher bird habitat quality in conservation plots than in non-conservation plots. Bees as chief pollinators, bees visiting conservation plots during 50 % flowering per square meter ranged from 5 to 11, compared to 2–6 in non-conservation plots. Bee visitation to bean flowers has a significant influence on productivity, as it influences pollen transfer and fertilization. Common beans yield among plots ranged 0.9 tons/ha to 1.4 tons/ha in conservation plots compared to 0.35–1.01 tons/ha, in non-conservation plots. Land use conservation contributes considerably to economic growth through increased productivity and reduced production costs, where the production cost is reduced by 50 % in conservation plots compared with non-conservation plots. However, the present study was conducted in a single location with smallholder farmers; hence, further experiments over larger areas and longer time periods are needed for a more robust conclusion.