Experimental Treatments Research Articles

Effects of Water, Fertilizer and Heat Coupling on Soil Hydrothermal Conditions and Yield and Quality of Annona squamosa

Seasonal drought and summer soil high-temperature stress in Southern China often lead to decreased yield and quality of Annona squamosa. It is important to explore reasonable and effective water and fertilizer management measures as well as cover measures to improve the soil hydrothermal conditions in orchards to realize the increase in yield and quality of Annona squamosa. This study involved a two-year (2022–2023) field experiment in Yun County, Lincang City, Yunnan Province, using three factors and a three-level orthogonal test, resulting in nine different experimental treatments for water, fertilizer and heat. The three irrigation levels were W1 (soil moisture content of 55% of field moisture capacity), W2 (soil moisture content of 75% of field moisture capacity) and W3 (soil moisture content of 85% of field moisture capacity). The three fertilizer levels were F1 (1666 kg·hm−2), F2 (2083 kg·hm−2) and F3 (2500 kg·hm−2), and the three cover methods were A1 (no cover), A2 (fresh grass cover) and A3 (straw cover). The effects of these treatments on soil hydrothermal conditions, growth indices and fruit yield and quality of Annona s1uamosa were systematically monitored and analyzed, and the relationships between these treatments and yield and quality was analyzed based on a Mantel test. The results showed that T5 (W2F2A3) had the highest average soil moisture content over two years, followed by T7 (W3F1A3). The T7 (W3F1A3) treatment effectively reduced soil temperature by 5 °C compared to T1 (W1F1A1). T5 (W2F2A3) had the highest average yield over two years, with an increase of 33.99% compared to T1 (W1F1A1). Additionally, T5 (W2F2A3) has the highest average soluble solids, soluble sugars and vitamin C content over two years, with increases of 28.13%, 13.36% and 4.86%, respectively, compared to T1 (W1F1A1). A Pearson correlation analysis showed that there was a significant correlation between Annona squamosa growth and soil moisture content and soil temperature, and the Mantel test showed that soil hydrothermal conditions had significant influence on the growth and yield. T5 (W2F2A3) has the highest comprehensive benefit in promoting growth, increasing yield and improving quality for the plant. The effects of different irrigation quantities, fertilizer amounts and different cover measures on the coupling interaction for soil hydrothermal status in the root zone, growth, yield and quality of Annona squamosa were investigated, providing reliable theoretical support for the scientific planting model of Annona squamosa in the low-heat river valley of Yunnan Province.

Evaluating chickpea varietal performance under different levels of phosphorus application

Chickpea, a vital legume crop, faces yield limitations due to factors like climatic conditions, nutrition deficiency in soil etc. Therefore, the knowledge of adoptive varieties to prevailing climatic conditions and enhancement yield by nutrient management is essential. The present investigation was carried out to assess the effect of varying levels of phosphorus on growth and yield of chickpea, at Agricultural Research Farm of SGRR University, Dehradun during Rabi season of 2022-23. The treatments of experiment comprise two chickpea varieties viz., PG-186 (V1) and Type 9 (V2) and five levels of phosphorus application i.e., 0, 15, 30, 45 and 60 kg P2O5/ha which were replicated thrice in factorial randomize design. The growth and yield parameters were recorded during different crop growth stages to get the response of treatments. The recorded data shows that the variety Type 9 perform better than variety PG-186 in most of the growth and yield attributing characters. Among the phosphorus doses the application of 45 kg P2O5/ha was perform best among all other treatments. The interaction effects of variety Type 9 with 45 kg P2O5/ha (V2T4) showed maximum growth and yield attributing characters over the other treatment combinations like plant height (46.66 cm), number of branches per plant (5.67), dry matter accumulation in plant (30.67 g), 1000 seeds weight (140.00 g) and seeds yield per hectare (14.30 q/ha). Based on experimental findings it can be concluded that variety Type 9 with application of 45 kg P2O5 /ha is best among all other treatments for higher yield of chickpea at Doon valley of Uttarakhand.

Multi-arm multi-stage survival trial design with arm-specific stopping rule

ABSTRACT Traditional two-arm randomized trial designs have played a pivotal role in establishing the efficacy of medical interventions. However, their efficiency is often compromised when confronted with multiple experimental treatments or limited resources. In response to these challenges, the multi-arm multi-stage designs have emerged, enabling the simultaneous evaluation of multiple treatments within a single trial. In such an approach, if an arm meets efficacy success criteria at an interim stage, the whole trial stops and the arm is selected for further study. However when multiple treatment arms are active, stopping the trial at the moment one arm achieves success diminishes the probability of selecting the best arm. To address this issue, we have developed a group sequential multi-arm multi-stage survival trial design with an arm-specific stopping rule. The proposed method controls the familywise type I error in a strong sense and selects the best promising treatment arm with a high probability.

Wastewater and warming effects on aquatic invertebrates: Experimental insights into multi-level biodiversity consequences

Wastewater effluents and global warming affect freshwater ecosystems and impact their crucial biodiversity. Our study aimed at characterizing individual and combined impacts of wastewater effluent and increased water temperature (as one aspect of climate change) on model freshwater communities. We tested the effect of experimental treatments on genetic diversity, survival, body weight, total lipid content, lipidome and metabolome of individual species as well as community composition and phylogenetic diversity. In a 21-day mesocosm experiment we assessed the responses of a simplified freshwater food web comprising of moss and seven species of benthic macroinvertebrate shredders and grazers (mayflies, stoneflies, caddisflies and amphipods) to four treatments in a full factorial design: control, increased water temperature, wastewater and a multiple stressor treatment combining increased temperature and wastewater. Physiological responses varied among taxa, with species-specific sensitivities observed in survival and lipid content. The lowest total lipid content was observed in caddisflies and a mayfly subjected to multiple stressor treatment. The effects of stressors were reflected in the altered metabolic pathways and lipid metabolism of the individual taxa, with differential treatment effects also observed between taxa. A notable decrease in phylogenetic diversity was observed across all experimental communities. Gammarus fossarum demonstrated a high susceptibility to environmental stressors at the genetic level. Hence, while commonly used indicators of ecosystem health (e.g. community composition) remained stable, molecular indicators (e.g. phylogenetic diversity, metabolome and lipidome) responded readily to experimental treatments. These findings underscore the vulnerability of macroinvertebrates to environmental stressors, even over relatively short exposure periods. They highlight the importance of molecular indicators in detecting immediate ecological impacts, offering valuable information for conservation strategies and understanding the ecological consequences in freshwater ecosystems.

N Stress Alleviation in Crops—A System Approach Analysing Residual N From Winter Crops in a Late‐Maize‐Wheat Sequence

ABSTRACTNitrogen (N) is crucial for crop production. Crop sequences with different legume participation affect N availability and therefore N fertiliser management. The study aimed to assess the inclusion of winter crops (WC) with different amounts of residues and different C:N ratios on the following: (i) the response to N fertilisation in the following late‐maize (Zea mays L.), and to carry that comparison into a subsequent wheat crop (Triticum aestivum L.), and (ii) identify soil N indicators associated with these responses. Two field experiments (E1 and E2) were conducted in the Argentinean Pampas during two growing seasons to evaluate a WC/late‐maize‐wheat sequence under no‐tillage. In each experiment, late‐maize was sown after a bare‐fallow and three WC: wheat, vetch (Vicia villosa L.) and field pea (Pisum sativum L.), where five rates of N fertilisation were evaluated. An area of late‐maize that was not fertilised with N within each previous WC was used to evaluate the response to N fertilisation in the subsequent wheat crop. Indigenous N was estimated by using N uptake in the non‐N‐fertilised treatments. Soil N indicators and C:N ratio of WC residues were evaluated as indicators of response to N fertilisation in both crops. Significant responses to N fertilisation in grain yield and N uptake were observed in late‐maize when bare‐fallow and wheat were the previous treatments in both experiments. In contrast, vetch and field pea supplied 32 and 40 kg N ha−1 in E1 and E2, respectively, and showed no response to N fertilisation, satisfying the N required by late‐maize. However, this supply was not enough to sustain the N demand of the subsequent wheat, where the response to N addition ranged from 36% to 74% when vetch and wheat were the previous WC, respectively. Only soil inorganic N indicators were associated with indigenous N supply. Moreover, the apparent net WC effect was linked to late‐maize (r2 = 0.91) and subsequent wheat (r2 = 0.67) grain yield response, which was also related to the C:N ratio of the WC residues in late‐maize and the subsequent wheat (r2 = 0.78), suggesting that mineralisation occurs when C:N ratio is below 18. Consequently, in future studies the C:N ratio of the WC residues can be included in N fertilisation recommendation schemes when late‐maize is sown as a double crop in more intensified crop sequences.

Latitudinal trends in an invasive plant: genetic differentiation, phenotypic plasticity, and the effects of heavy metals and herbivores on growth, defence, and reproductive characteristics

Abstract Background and Aims Invasive species usually demonstrate remarkable adaptability across diverse environments, successfully inhabiting a wide variety of regions. This adaptability often links to genetic differentiation and phenotypic plasticity, leading to latitudinal trends in phenotypic traits. In this study, we collected seeds of invasive plant Phytolacca americana from different latitudes and planted them in homogeneous gardens to investigate the latitudinal variation of P. americana phenotypic traits and to evaluate the effects of herbivory and heavy metals on plant growth, defence, and reproductive characteristics. Methods P. americana seeds from different latitudes were planted in a homogeneous garden. For the experimental treatment, the seeds were divided into four groups: a heavy metal treatment group and its corresponding control group, and a cover treatment group with its corresponding control group. After the fruits matured, their growth, reproduction, and defence indicators were measured. Key Results Significant latitudinal trends were observed in P. americana’s growth and defence characteristics, including changes in branch number, underground biomass, total biomass, and leaf tannin content. Compared to previous field surveys on P. americana, our study found that the latitude trends in growth structure and defence traits were consistent. But the latitudinal trend of reproductive structure is different. Moreover, heavy metals and herbivory substantially influenced the plant’s growth, reproduction, and defence mechanisms, further shaping its latitudinal patterns. Conclusions The observed phenotypic variations in P. americana across latitudes can be largely attributed to the synergistic effects of phenotypic plasticity and genetic variation. At a broader geographical scale, adaptations to heavy metal stress and herbivory pressure among different P. americana populations involve distinct trade-offs related to growth, reproduction, and defence strategies.

Effects of the combination of biochar and organic fertilizer on soil properties and agronomic attributes of soybean (Glycine max L.)

This research aimed to investigate the impacts of a combination of rice husk biochar and organic fertilizer on the physical and chemical properties of soil, the population of soil bacteria, the relative chlorophyll content of leaves, the development of soybean root nodules, and yield components under strongly acid soil conditions. A greenhouse and pot experiment was designed using a randomize complete block design with factorial 2 × 3 treatments and three replications. The experimental treatments comprised two rates of biochar (35 and 70 g/pot) and three rates of organic fertilizer (70, 105, and 140 g/pot). After 100 days of amendment of strongly acidic soils, the results showed that application of treatments B35F70 and B70F140 increased soil pH by 16.80% compared to the control group (CK). On the other hand, treatments B35F140 and B70F105 resulted in an increase of soil electrical conductivity by 66.67% compared to CK. In addition, after 100 days of amendment with treatments B35F105, B35F105, B35F140, B70F105, B70F70, B70F70, and B35F140, organic matter, available phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), and zinc (Zn), organic matter, available phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), and zinc (Zn), significantly increased when compared to the control group (CK). Treatment B35F140 increased relative leaf chlorophyll content and soybean seed weight per plant by 60.76% and 100.56%, respectively when compared to the CK. Furthermore, treatment B35F70 produced 125% more root nodules than CK. Moreover, each amended strongly acid soil resulted with a significant upsurge in total soil bacteria compared to the CK. Overall, statistics proved that a combination of biochar and organic fertilizer improved soil properties and soybean agronomic attributes.

Oxidative Challenges Do Not Impact Pheomelanin-Dependent Coloration in Male Japanese Quails.

Colorful traits play an important role in animal communication. Melanin-based colorations are the most extended color traits in animals and are produced by two types of endogenous melanic pigments: eumelanins and pheomelanins, the last ones being the least studied in the context of communication. The production of pheomelanin requires a semi-essential amino acid, cysteine, which is also used for the synthesis of an important endogenous antioxidant, glutathione. Hence, it has been proposed that the synthesis of pheomelanin and glutathione may compete for the cysteine available in the organism. In that case, pheomelanic colorations are predicted to be less intense when the individual is facing an oxidative challenge, and therefore, they would provide information on the oxidative status of the bearer. Here, we experimentally evaluated this hypothesis using male Japanese quails (Coturnix japonica) as a model of study, a species with pheomelanin-based plumage in the breast and cheeks. During feather growth, individuals were exposed to one of three possible conditions: Control (saline), an endogenous oxidative challenge (Escherichia coli lipopolysaccharide injections), or an exogenous oxidative challenge (paraquat injections). Contrary to predictions, we found that: (1) Birds from the three groups exhibited less intense pheomelanic colorations in feathers after the experimental manipulation, and the magnitude of this change did not differ among groups. (2) There was no effect of the experimental treatments on the proportion reduced/oxidized glutathione, an index of oxidative status. (3) Lipid peroxidation was lower after the experimental manipulation, with birds exposed to the paraquat challenge experiencing a stronger decline than other groups. (4) Cysteine and total glutathione levels decreased after the experimental manipulation, with no differences per group in the magnitude of the decline. Taken together the results do not support the hypothesis that oxidative status plays a key role at determining the variation in the intensity of pheomelanic colorations.

Effects of simulated precipitation changes on soil respiration:Progress and prospects.

Soil respiration, the main pathway for transferring terrestrial carbon pool to atmospheric carbon pool, is profoundly affected by the intensification in global precipitation variability in the context of climate change. Nowadays, variable controlling methods and field manipulation experiments are two main methods widely used to investigate the effects of simulated precipitation changes on soil respiration. Yet, due to the heterogeneity of soil properties, vegetation types, and the magnitude of precipitation change, there is substantial inconsistency in the conclusions of simulated precipitation change effects on soil respiration. Here, we analyzed data from domestic and foreign literature, and examined the effects of simulated precipitation change on soil respiration. Firstly, we described the response pattern of soil respiration to soil moisture fluctuation and pointed out that the magnitude and direction of the response of soil respiration to simulated precipitation change depended on whether soil moisture was optimally conditioned at different precipitation treatments. Second, we summarized the response patterns of soil respiration to symmetric increase and decrease in precipitation, which mainly included symmetric and asymmetric responses (positive and negative asymmetric). Meanwhile, the adaptation of plants and soil microorganisms to drought stress and soil oxygen limitation, as well as the reduction of organic substrates, were the main mechanisms accounting for the shifts of soil respiration response patterns to simulated precipitation change from symmetric to asymmetric responses. Third, we identified a significant effect of ambient climate on soil respiration in response to precipitation treatments as increasing duration of the experimental treatments. In addition, cumulative or buffering effects of ambient climatic conditions on precipitation treatment could affect the sensitivity of soil respiration along precipitation gradient by altering hydrothermal conditions. Finally, to accurately assess the implications of precipitation changes on soil carbon balance processes, we proposed three aspects of future precipitation effects on soil respiration for attention: 1) focusing on the phenomenon of "threshold effects" in the asymmetric response of soil respiration along precipitation gradients; 2) distinguishing the intrinsic mechanisms of autotrophic and heterotrophic components in soil respiration in response to precipitation changes; and 3) focusing on the impacts of intensified precipitation variability on soil respiration in the context of future climate extremes. In conclusion, with the intensified variability in global precipitation patterns, clarifying the response mechanism of soil respiration to precipitation changes is of great significance for accurately predicting and evaluating the alterations of soil carbon cycle processes and carbon balance in the context of global changes.

Drought impairs detritivore feeding activity more strongly in northern than in southern European latitudes

Soil detritivores play key roles in decomposition processes closely related to ecosystem services. Drought and soil organic carbon depletion due to agricultural management are detrimental to soil biodiversity, but their interactive effects on soil biota and associated processes have not been thoroughly investigated. In 2018, we used rain-out shelters to experimentally induce drought in wheat fields of contrasting levels of organic carbon in Sweden, Germany and Spain. That year Europe experienced a climatic dipole, with exceptionally severe droughts in northern latitudes. We assessed the feeding activity of soil detritivores by bait-lamina tests, and measured several abiotic and biotic soil parameters. In the peak of the dipole drought (summer) southern fields had the driest soils. Nonetheless, detritivore feeding activity responded to the experimental drought by shifting to deeper soil layers there. Low soil organic carbon (SOC) levels exacerbated the latter effect. However, in this same period, feeding activity in northern and central Europe was two orders of magnitude lower than in the south, and failed to respond to either the experimental treatment and/or SOC levels. Using mixed-effects longitudinal random forests, we detected various candidate drivers of detritivore feeding activity: soil moisture, phosphorus content, bacteria and nematodes. Different bacterial taxa were associated to detritivory in each country, but their potential influence was pervasive. Thus, our results suggest that drought had adverse effects on detritivore feeding, which were exacerbated northwards due to the climatic dipole. Increased SOC levels mitigated drought effects only in southern soils. Regional adaptation of soil biota to aridity could explain the response of detritivores in southern Europe to drought. Machine learning algorithms arise as useful tools for exploring potential drivers relating biodiversity to soil processes. Overall, future research on the effects of drought on soil biodiversity and processes will be key for tackling climate change impacts in terrestrial ecosystems.

Exploring the Effects of Irrigation Schedules on Evapotranspiration Partitioning and Crop Water Productivity of Winter Wheat (Triticum aestivum L.) in North China Plain Using RZWQM2

ABSTRACTA significant basis for winter wheat production in China is the North China Plain (NCP). However, winter wheat production is severely hampered by water shortages in this area. Transpiration co‐occurs with photosynthesis, affecting crop water productivity (CWP). The purpose of this experiment is to use Root Zone Water Quality Model (RZWQM2) to study actual transpiration (AT) and evaporation (AE) under different irrigation schedules and then determine its impact on grain yield and CWP. In the 2019–2022 winter wheat growing seasons, four experimental treatments were set up: no irrigation during growth period (I0), irrigation at jointing stage (I1), irrigation at jointing and anthesis stage (I2) and irrigation at jointing, anthesis and filling stage (I3), and the RZWQM2 model was calibrated and verified in this experiment. A higher yield (7840.90 kg/ha for an average of 3 years) and the highest CWP can be obtained in I2 treatment (increased by 12.72%, 5.98% and 4.28% for an average of 3 years, respectively, compared to the other three treatments). The model has a good simulation effect on soil water dynamic change and plant physiological performance of the four treatments; the model showed that irrigation increased the simulated AE and AT; however, reduced AE/actual evapotranspiration. For the whole growth period, AT in I3, I2, I1 and I0 was 351.70, 317.30, 271.50 and 223.70 mm, respectively. Especially in the late growth stage of winter wheat, the AT in I3 was 65.20 mm for an average of 3 years, which was significantly higher than I2, I1 and I0 by 31.60, 13.50 and 10.00 mm, respectively. Thus, I3 increased AT at the late growth stage of winter wheat and resulted in an increase in grain yield; however, it did not significantly increase CWP. This study demonstrated that irrigation at winter wheat jointing and anthesis stages can improve the CWP to achieve the goal of stable grain yield and water saving.

Effect of Integrated Weed Management Practices in Rice (Oryza sativa) Under SRI

An experimental study was conducted at the Annamalai University Experimental Farm in Cuddalore District, Tamil Nadu, between February and May 2023. The objective of this work is to chemically manage the developing weeds in rice during vegetative development using the System of Rice Intensification (SRI) technology. Additionally, the study aims to identify the weed flora in the experimental field. In this study, a Randomised Block Design with three replications was employed. The experimental treatments comprised optimal combinations of chemical and mechanical techniques for weed management. The experiment was structured in a randomised block design, consisting of seven treatments, and subsequently reproduced three times. Among the several treatments, the application of Penoxsulam + Butachlor @ 2L/ha (PE) on 3 days after transplantation (DAT) for rice, and the use of Conoweeder twice on 25 and 35 DAT (rice), effectively decreased weed density and thus reduced weed biomass. This led to an improvement in crop development and production. The greater plant height, drying matter potential (DMP), and grain yield seen with the application of Penoxsulam + Butachlor @ 2L/ha (PE) on 3 days after transplantation (DAT), and Conoweeder twice on 25 and 35 DAT, may be attributed to the effective management of a weed-free environment, especially during critical growth phases of the crop. Suppression of agricultural weed competition facilitated increased growth and development of rice crop, resulting in elevated grain and straw yield.

Effect of Eighteen Years of Continuous Crop Residue Application on Crop Yields, Soil P Fractions, and Crop P Uptake in Conservation Tillage Under Semi-Arid Tropical Rainfed Conditions

The continuous use of crop residue in soil can enhance the crop yield and potential availability and mobility of P fractions to crops in conservation tillage. A field experiment was conducted to assess the long-term effects of surface crop residue applications on soil P fractions and their relationship with P uptake and crop yields. Field experiment was conducted at ICAR-Central Research Institute for Dryland Agriculture, Hyderabad, India during 2005 to 2022. The experimental treatments applied were: T1 - no crop residue application, T2 - application of crop residue @ 2 t ha-1, T3 - application of crop residue @ 4 t ha-1, and T4 - application of crop residue @ 6 t ha-1 in conservation tillage. The test crops viz. sorghum (Sorghum vulgare) and cowpea (Vigna unguiculata) were grown in a yearly rotation every year in the kharif season in conservation tillage. The results of the long-term study revealed that the per cent increase in sorghum (Sorghum vulgare) grain yield with the application of crop residue at the rate of 2, 4 and 6 t crop residue ha-1was to the tune of 7.9, 16.1 and 26.0%, respectively over no crop residue application. Similarly, the per cent increase in the cowpea (Vigna unguiculata) seed yield was to the extent of 25.2, 43.0 and 64.1% in 2, 4 and 6 t ha-1, respectively over no crop residue application. The sorghum and cowpea stover yield also significantly (p=0.05%) increased with the added levels of the crop residue. Significantly higher P uptake by sorghum and cowpea was recorded in 6 t crop residue ha-1 as compared to the other crop residue treatments. Results of the current study also showed the significant positive response of long-term crop residue application on the P fractions viz., water-soluble phosphorus (WS-P), aluminum bound P (Al-P), iron bound P (Fe-P), calcium bound P (Ca-P) and reductant soluble P (RS-P), and on available P and total P in soil as compared to no crop residue application. The average percent contribution of P fractions toward the sum-total of extracted P was in the order: Fe-P (30.8%)>RS-P (30.7%)>Al-P (24.2%)>Ca-P (9.4%)>WS-P (4.8%). The WS-P and Al-P were found to be the P fractions indicating their specificity by cowpea crop, and WS-P and Ca-P were found to be P fractions indicating their specificity by sorghum crop. The results of the present study will be highly useful in understanding the effect of crop residue application in conservation tillage on the P fractions and their contribution toward P uptake and crop yields.

Abstract A073: Desmoglein-2 is a regulator of pancreatic ductal adenocarcinoma progression

Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, with a dismal 5-year survival rate of <13%. We have discovered that desmoglein-2 (DSG2), a cell surface protein, is highly expressed on PDAC cells. In silico data indicate that elevated levels of DSG2 is associated with PDAC progression and poor patient survival. Immunohistochemistry (IHC) analysis of a tissue microarray of 302 patient samples showed that DSG2 was expressed by >90% of PDAC patients. We hypothesized that DSG2 is an under-appreciated contributor to PDAC progression and that DSG2 can be targeted. The main aims of this study were to: 1) investigate the role of DSG2 in PDAC cell function in vitro, 2) investigate the molecular biology underpinning the role of DSG2 in PDAC, and 3) to use murine PDAC tumor models to evaluate the contribution of DSG2 to cancer progression in vivo. Our in vitro data showed that reducing the expression of DSG2 (via small interfering RNA (siRNA)) significantly decreased PDAC cell proliferation, migration, and invasion. Moreover, signaling analysis of PDAC cells with or without DSG2 (via siRNA) using a reverse-phase protein array and cytokine array revealed that DSG2 modulates pro-tumorigenic and pro-metastatic cellular pathways, through reducing the effects of certain proteins. Particular alterations were observed in pathways involving gene regulation (e.g., beta-catenin), migration (e.g., epidermal growth factor receptor and integrin-beta1), and cytokine release (e.g., serpine-1). Next, in an orthotopic xenograft mouse model, BxPC-3 PDAC cells with a stable knockdown of DSG2 (via short-hairpin RNA) were injected into NSG (NOD scid gamma) mice, where we observed a significant reduction in tumor burden and liver metastasis when compared to control mice. IHC staining of tumor sections revealed that the DSG2 knockdown tumors contained reduced levels of collagen, tumor vasculature and cancer associated fibroblasts. Thus, suggesting that DSG2 also has a modulatory effect on the tumor microenvironment (TME). A similar reduction in tumor burden, cancer progression and changes to the TME were observed when a neutralizing anti-DSG2 monoclonal antibody was administered intraperitoneally twice a week at 5mg/kg to BxPC-3 tumor bearing mice. Finally, to investigate the immune cell landscape, we used an orthotopic syngeneic mouse model, whereby Dsg2 was knocked out of KPC (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) mouse PDAC cells via clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9. This mouse model also showed that loss of Dsg2 resulted in a significant reduction in tumor burden, cancer cell metastasis and changes to the TME. In summary, we have identified a potential new target for the treatment of PDAC, namely DSG2, and future experiments are pursuing clinical opportunities to improve PDAC patient survival. Citation Format: Charlie B Ffrench, Kay K Myo Min, Mark DeNichilo, Michaelia P Cockshell, Emma L Dorward, Emma J Thompson, Michael Ortiz, Michael S Samuel, Savio George Barreto, Claudine S Bonder. Desmoglein-2 is a regulator of pancreatic ductal adenocarcinoma progression [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A073.

Sequential [177Lu]Lu-PSMA-617 and docetaxel versus docetaxel in patients with metastatic hormone-sensitive prostate cancer (UpFrontPSMA): a multicentre, open-label, randomised, phase 2 study

Lutetium-177 [177Lu]Lu-prostate-specific membrane antigen (PSMA)-617 improves survival and quality of life in patients with metastatic castration-resistant prostate cancer, but whether it confers a benefit in hormone-sensitive disease is unknown. We aimed to evaluate [177Lu]Lu-PSMA-617 before docetaxel treatment in patients with de-novo high-volume metastatic hormone-sensitive prostate cancer. UpFrontPSMA was an investigator-initiated, multicentre, open-label, randomised, phase 2 trial done at 11 Australian hospitals. Eligible patients had prostate adenocarcinoma without clinically significant neuroendocrine differentiation or small-cell histology, were aged 18 years or older, had less than 4 weeks on androgen deprivation therapy, had an Eastern Cooperative Oncology Group performance status of 0-2, and had high-volume PSMA-avid disease on [68Ga]Ga-PSMA-11 PET-CT with no major discordance on 2-[18F] fluorodeoxyglucose-PET-CT. Patients were randomly assigned (1:1) to the experimental treatment ([177Lu]Lu-PSMA-617 followed 6 weeks later by docetaxel) or standard-of-care treatment (docetaxel alone) using computer-based block randomisation with random block sizes, stratified by disease volume by conventional imaging and duration of androgen deprivation therapy at the time of registration. Neither patients nor investigators were masked to treatment assignment. Patients in the experimental group received two cycles of [177Lu]Lu-PSMA-617 7·5 GBq every 6 weeks intravenously, followed 6 weeks later by six cycles of docetaxel 75 mg/m2 every 3 weeks intravenously, whereas patients in the standard-of-care treatment group received six cycles of docetaxel 75 mg/m2 every 3 weeks intravenously. All patients received continuous androgen deprivation therapy. The primary endpoint was undetectable prostate-specific antigen (≤0·2 ng/mL) at 48 weeks, assessed using a modified intention-to-treat analysis. The trial is registered with ClinicalTrials.gov, NCT04343885. Between May 5, 2020, and April 18, 2023, 130 patients were randomly assigned, 63 (48%) to [177Lu]Lu-PSMA-617 plus docetaxel and 67 (52%) to docetaxel alone. All patients were male and no race or ethnicity data were collected. Median follow-up was 2·5 years (IQR 1·8-3·0). Four patients in the docetaxel alone group withdrew consent after randomisation and no data beyond screening were collected. An additional four patients were not evaluable for the primary endpoint at 48 weeks (two in each group). 25 (41%) of 61 patients (95% CI 30-54) in the [177Lu]Lu-PSMA-617 plus docetaxel group had undetectable PSA at 48 weeks compared with ten (16%) of 61 patients (9-28) in the docetaxel alone group (OR 3·88, 95% CI 1·61-9·38; p=0·0020). The most common grade 3 or 4 treatment-related adverse events were febrile neutropenia (seven [11%] of 63 patients in the [177Lu]Lu-PSMA-617 plus docetaxel group vs six [10%] of 63 patients in the docetaxel alone group) and diarrhoea (four [6%] of 63 patients vs none). Serious adverse events occurred in 16 (25%) patients in the [177Lu]Lu-PSMA-617 plus docetaxel group (none were definitely related to [177Lu]Lu-PSMA-617) and 16 (25%) patients in the docetaxel alone group. No treatment-related deaths occurred. [177Lu]Lu-PSMA-617 followed by docetaxel improved antitumour activity in patients with de-novo high-volume metastatic hormone-sensitive prostate cancer compared with docetaxel alone, without increased toxic effects. Our data potentially support a role for [177Lu]Lu-PSMA-617 in metastatic hormone-sensitive prostate cancer. Prostate Cancer Research Alliance (Movember Foundation and Australian Government Medical Research Future Fund), US Department of Defence Impact Award-Clinical Trials, Endocyte/Advanced Accelerator Applications (a Novartis company), Australian Nuclear Science and Technology Organization, Victorian Cancer Agency, University of Melbourne, and Peter MacCallum Cancer Foundation.

PSLBII-28 Effects of dietary protein manipulation on greenhouse gases and ammonia emissions from feedlot beef steers

Abstract Black Angus steers [n = 112; body weight (BW) = 401 ± 3.6 kg] were used in a randomized incomplete block design to evaluate the effects of 3 rumen available protein to microbial crude protein ratios (RAP:MCP) on growth performance, and gaseous emissions from feedlot steers. Steers were blocked by initial BW and randomly assigned to 1 of 3 treatment rations. Diets were fed rations either Deficient (-150 gּ animal-1ּ d-1; DEF), Balanced (0 gּ animal-1ּ d-1; BAL), or Excess (+150 gּ animal-1ּ d-1; EXS) in RAP: MCP. Steers were allocated and housed in cattle pen enclosures (CPE), and treatment diets were delivered daily as a total mixed ration. The present study consisted of two 42-d periods. Refusals were collected weekly and BW every 14 d. Gas measurements were obtained daily in sequential order from all CPE. Data were analyzed with R statistical software (4.2.3). The linear mixed effect model procedure within the “lme4” package was used with CPE as the experimental unit, treatment and week as fixed effects, and block and period as random effects. A contrast coefficient matrix was constructed to test for linear and quadratic effects. Initial, intermediary and final BW were not different for steers receiving the varying RAP:MCP (P ≥ 0.239). A treatment effect (P = 0.004) was observed for mean dry matter intake (DMI) where EXS steers consumed 0.46 kg more DM compared with BAL steers, but DEF steers had similar DMI to those fed EXS and BAL (P = 0.189). Average daily gain (ADG) was only affected by treatment (P = 0.007) on d 0 to 14 where steers receiving DEF gained 0.6 kg more than those fed BAL (P = 0.010), but those fed EXS had similar ADG. Similar to ADG, gain to feed (G:F) was affected by treatment (P = 0.012) only during d 0 to 14. Mean CH4 production from steers fed DEF and EXS were 20% and 13% greater (P = 0.010) compared with those fed BAL, respectively; however, CH4 from EXS vs. DEF steers was not different (P = 0.149). Mean cumulative NH3 emissions increased linearly by treatment with EXS steers emitting up to 52% more NH3 compared with those receiving DEF (P < 0.001). Similarly, EXS steers had increased SO2 emissions by up to 44% compared with those fed DEF (P < 0.001). Emissions of CO2, N2O, and H2S were similar (P > 0.100). The manipulation of RAP:MCP in the diets of feedlot steers can drastically reduce NH3 emissions without affecting growth performance and may be a valuable tool to reduce air pollution from beef production systems.

PSXII-24 Use of a commercial blend of tannins as feed additive for feed lot cattle on large pen trial improves carcass weight and carcass feed conversion

Abstract The utilization of commercial tannin extracts as feed additives holds promise for enhancing animal performance and health within commercial feedlot settings. This study aimed to assess the impact of a commercial tannin blend, SilvaFeed BX (Indunor, Buenos Aires, Argentina), sourced from quebracho and chestnut extracts along with saponins, on the performance of beef cattle. Nelore bullocks (n = 1,198) were allocated to 12 pens in a completely randomized block design, stratified by initial date, at a commercial feedlot facility in Goias State, Brazil. Each pen served as an experimental unit, with 10 pens housing 100 animals each and 2 pens containing 99 animals each. The experimental treatments included a Control diet with monensin alone [25 ppm/kg dry matter (DM)] or treated with BX (0.7 g/kg DM) on top of the control diet. Individual body weights (BW) were recorded at processing (initial BW; IBW) and shipment (final BW; FBW), while DM intake (DMI) was averaged per pen throughout the study duration. Carcass weight (CW) was individually measured at the packing plant, and carcass gain was calculated as the discrepancy between carcass weight and the estimated initial carcass weight, set at 50% of the IBW, aligning with customary practices for negotiating feeder cattle in Brazil. Statistical analyses were conducted using Proc Glimmix in SAS, treating pens and treatments as fixed effects and blocks as random effects, with IBW considered as a covariate. Residuals were assessed for normality, identifying three outliers. Mean comparisons were facilitated using LSMEANS. The results indicated that BX-treated cattle exhibited increased FBW (502.17 vs. 493.64 kg, P = 0.0992), carcass weight (275.76 vs. 268.78 kg, P = 0.0343), total carcass gain (107.52 vs. 100.54 kg, P = 0.0343), and improved carcass feed conversion (10.46 vs. 11.45 kg DM/kg; Table). Despite numerical differences, the limited number of replications were not enough to detect significant differences between treatments in average daily gain (P = 0.2419), DMI (P = 0.5508), feed conversion (P = 0.2641), or dressing (P = 0.3757). In conclusion, BX, a blend of tannins, exhibits potential for enhancing carcass weight and feed conversion efficiency in Nelore bullocks. Further investigations employing larger sample sizes are warranted to comprehensively elucidate its effects on other performance parameters.

Dietary supplementation with a blend composed of carvacrol, tannic acid derived from Castanea sativa and Glycyrrhiza glabra, and glycerides of medium chain fatty acids for weanling piglets raised in commercial farm.

This study aimed to evaluate the dietary administration of a blend composed of carvacrol, tannic acid derived from Castanea sativa mill and Glycyrrhiza glabra, medium chain fatty acids (MCFAs) glycerides for weanling piglets. An in vitro digestion followed by total phenolic content (TPC) and total antioxidant activity (TAC) assessment was performed before the in vivo application. At weaning, a total of 210 piglets were randomly allocated to two experimental treatments (7 replicates/15 piglets for each replicate). Control group (CTR) was fed a standard basal diet while the treated group (T) was fed the basal diet mixed with 1.500mg/kg of blend. After in vitro digestion, TPC and TAC evidenced peaks at the end of oral and gastric phases in comparison to the intestinal one in line with the high content of phenolic compound (P < 0.05). Treatment conditioned body weight and average daily gain (P < 0.05), fecal score on 6, 7, and 8 d after weaning (P < 0.05). At 35d, the T group showed a decrease in salivary cortisol compared to CTR (P < 0.05). Duodenum and jejunum sections of T piglets revealed higher villi (P < 0.05), deeper crypts (P < 0.01), and increased V/C ratio (P < 0.01). CTR showed a higher expression of duodenal Occludin (P < 0.05). Jejunal E-cadherin and Occludin were more expressed in T jejunum sections (P < 0.05). Twelve differentially abundant genera were identified in T group caecal samples. Potentially harmful Clostridium sensu stricto 13 was reduced by the treatment (P < 0.05). In conclusion, the tested blend positively affected salivary stress markers and the gut health of weaned piglets.

132 Evaluation of a phytogenic feed additive containing garlic, clove, and capsicum oleoresin on the health and performance of newly received, high-risk calves

Abstract Abstract: The objective of this experiment was to evaluate the effects of a phytogenic feed additive (PHYT) on the health and performance of newly-received, high-risk calves. Auction market derived crossbred beef steers and bulls (n = 712; initial body weight; BW = 239 ± 6.8 kg) were stratified by sex, blocked by BW, and randomly allocated to experimental treatments (n = 9 pens per treatment; n = 24 to 29 calves per pen). Experimental treatments included: a control diet (CON), 250 mg · steer⁻¹ · d⁻¹ of PHYT (PHYT250), or 500 mg · steer ⁻¹ · d⁻¹ of PHYT (PHYT500). Pen served as the experimental unit for all dependent variables. Contrasts were performed for PHYT inclusion (PHYT250 and PHYT500 vs. CON). No differences in BW existed between treatments throughout the experiment (P ≥ 0.20; PHYT vs. CON P ≥ 0.11). In the overall model, no differences (P ≥ 0.23) in average daily gain (ADG) existed between CON, PHYT250, or PHYT500. However, when comparing PHTY to the CON, ADG tended to be less in the calves receiving CON from d 0 through d 14 (P = 0.09). No differences in dry matter intake (DMI) existed between treatments throughout the experiment (P ≥ 0.27; PHYT vs. CON P ≥ 0.13). While there was no difference in gain to feed (G:F) in the overall model (P ≥ 0.26), the tendency observed for a difference in ADG from d 0 through d 14 did result in a similar tendency for G:F across the same interval when comparing PHYT to the CON (PHYT vs. CON P ≥ 0.10). A difference was observed in the percentage of steers treated once for bovine respiratory disease (BRD; P = 0.02), with CON being treated more frequently than PHYT500, while PHYT250 was intermediate and similar to both CON and PHYT500. When comparing PHYT to the CON, there was a decrease in the percentage of steers receiving PHYT to be treated once for BRD (P = 0.01). However, there were no differences in either the percentage of steers treated twice for BRD or the in the percentage of total BRD treatments administered (P ≥ 0.29; PHYT vs. CON P ≥ 0.14). The mortality percentage and the percentage of steers removed from the study were not different (P ≥ 0.16; PHYT vs. CON P ≥ 0.14); however, there tended to be more combined mortalities and removals for steers receiving PHYT than the CON (P = 0.08; PHYT vs. CON P = 0.09), with PHYT500 and CON tending to be different, and PHYT250 being intermediate and similar to both PHYT500 and CON. In summary, PHYT did not impact overall performance, but did reduce initial antimicrobial treatments for BRD.

362 Nutrikinetic evaluation and modeling of 25-hydroxyvitamin D3 in beef cattle

Abstract The objective of this study was to evaluate serum 25-hydroxyvitamin D3 [25(OH)D3] status in beef cattle when 1) fed diets with supplemental 25(OH)D3 or calcidiol (HyD, dsm-firmenich, Plainsboro, NJ), and 2.) a single dose of calcidiol was administered to cannulated heifers on nutrikinetic evaluation and predictive modeling simulations. In experiment 1, crossbred heifer calves [n = 96, initial body weight (BW) = 222 ± 12.4 kg] were assembled from auction markets near Dickson, TN and transported ~1,069 km to Manhattan, KS. Heifers (n = 12 per pen) were stratified by BW and randomly allocated to a corn-based receiving diet with one of four dietary treatments: 1) No supplemental D3 or calcidiol (CON, n = 24), 2) 3,000 IU supplemental D3·heifer⁻¹·d⁻¹ (D3, n = 24), 3.) 0.5 mg calcidiol/h/d (Hy D Low, n = 24), or 4.) 1.0 mg calcidiol·heifer⁻¹·d⁻¹ (Hy D High, n = 24) for 60 d. Blood samples were collected from each heifer prior to transport (d -1), on arrival (d 0) and on d 14, 31, and 60 of dietary treatment period. Data were analyzed using the GLIMMIX procedure of SAS using animal as experimental unit and treatment as fixed effect. HyD High calves had greater (P &amp;lt; 0.001) serum 25(OH)D3 concentrations than HyD Low at d 14 and 31 (Figure 1 and 2). At d 14, 31 and 60, HyD High and HyD Low calves had greater (P &amp;lt; 0.001) serum 25(OH)D3 concentrations than CON or D3 treatments. In experiment 2, cannulated crossbred heifers (n = 8, initial BW = 289 ± 44.9 kg were randomly assigned to one of two treatments: 1.) 3 mg/272 kg BW calcidiol, or 2.) 5 mg/272 kg BW calcidiol in a single dose administered via rumen cannula at h 0. Serial blood samples were collected at baseline out to 70 d post-dose. Serum 25(OH)D3 concentrations were analyzed via HPLC coupled with tandem MS (dsm-firmenich, Belvidere, NJ). Predictive modeling simulations of serum 25(OH)D3 concentrations used non-parametric superposition (Certara Phoenix WinNonlin 64, St. Louis, MO) from applying non-compartmental analysis with the assumptions of linearity, independent calcidiol dose response, and the rate of absorption and the average systemic clearance were consistent for each calcidiol dosing interval. The elimination half-life (t1/2) of calcidiol was determined to be an average of 7.1 d and area under change in concentration-time curve time 0 to the last time point that measured above baseline concentration post dose (AUC0-last) averaged of 32.6 d (Table 1). Non-parametric dosing simulations using nutrikinetic parameters from experiment 2 suggest that administration of two 5 mg oral doses of calcidiol with daily feeding of 1 mg would result in a rapid and sustained increase in serum 25(OH)D3. However, simulations should be confirmed in vivo before implementation.