Biological Performance Research Articles

Impact of group discussion on student’s performance in biology (A case study of Heyik secondary school in Kaduna south local government area of Kaduna Nigeria)

This study assessed the impact of group discussions on students' academic performance in biology at Heyik Secondary School, Kaduna. The main objective was to explore how group discussions influenced students' understanding of biology, identify factors affecting their effectiveness, and address challenges like time management. Grounded in Behaviourism, Constructivism, Connectivism, and Experiential Learning Theories, the study used a survey design with 150 randomly selected senior secondary students. Data were collected via questionnaires and analyzed using SPSS, with descriptive statistics and correlation analysis to examine the relationships between group discussions, communication, and student performance. The findings showed a positive and significant correlation between communication within group discussions and improved biology performance. Both learning and development were also positively correlated with better academic outcomes, suggesting that group discussions enhance comprehension and retention. However, time management emerged as a key challenge, with scheduling conflicts and inefficient use of time limiting the benefits. The study recommends that educators focus on enhancing communication strategies, incorporating modern tools, and promoting continuous learning through curriculum and extracurricular activities. Continuous monitoring and evaluation, with regular assessments, will help refine communication and time management strategies based on student feedback and performances.

Influence of Language Skills on Biology Instructional Process in Secondary Schools in Kenya

Biology as a core science subject enables learners to conceptualize fundamental concepts such as genetics, evolution and cellular processes that underpin all living entities. Biological knowledge is also applied in addressing global challenges in fields such as medicine, agriculture and biotechnology. However, despite its significance, there has been a dismal performance in Biology in the country and Imenti-Central Sub-county for the last five years. Student performance in the subject not only depends on content mastery but also on language proficiency. Language serves as a primary medium for communicating the subject matter making good language skills essential for comprehension and expression of Biological content. However, minimal research has been conducted on the influence of language skills on Biology instructional process thus the need to undertake this study. The study investigated the influence of language skills on Biology instructional process in secondary schools in Imenti-Central Sub-county, Meru County, Kenya. A descriptive research design was adopted for data collection and analysis. The study sampled 352 participants from a population of 2950 participants using Yamane’s formula. Data was collected using questionnaires and interview schedules. Qualitative data was analyzed thematically while quantitative data was analyzed descriptively using percentages and frequencies and inferentially using Chi-square test with the aid of Statistical Package for the Social Sciences version 26 computer software. Findings indicated that language skills had a significant influence on Biology instructional process. Students’ language skills were therefore essential for effective Biology instruction. Based on the findings, the study recommended establishment of language development activities to enhance students’ language skills and varied teaching methods to demystify complex Biological terms.

Zinc Oxide-Based Endodontic Sealer with Proanthocyanidin-PLGA Nanoparticles: Synthesis and Physical Characterization

This study developed a zinc oxide-based endodontic sealer incorporating proanthocyanidin nanoparticles (PAC-NPs) encapsulated in poly(lactic-co-glycolic acid) (PLGA), utilizing PAC’s proven ability to enhance dentine collagen stability. The formulation was designed to provide both antimicrobial and collagen-stabilizing benefits, aiming to improve dentine-sealer interface integrity and prolong the functional lifespan of root canal treatments. Chemical characterization was conducted using Fourier Transform Infrared (ATR-FTIR) spectroscopy, confirming the presence of Zn-O and C=O bonds, indicative of the successful integration of zinc oxide and encapsulated PAC. Physical properties, including flow, setting time, solubility, and dimensional stability, were evaluated according to ISO 6876:2012 and ANSI/ADA standards 57, with the sealer meeting all clinical performance criteria. This preliminary characterization of the physical and chemical properties establishes a basis for further in vitro studies on the mechanical and biological performance of the sealer, aimed at validating its potential to enhance dentine collagen stabilization and material durability in endodontic applications.

The effect of alkaline heat treatment on titanium

The effect of alkaline heat treatment on titanium

Comparative Analysis of Bare and Quercetin-Loaded Nonionic Block Copolymer Micelles in an Artificial Gastrointestinal Medium.

Block copolymer micelles have been increasingly used for the solubilization and delivery of hydrophobic drugs. There exists a possibility of dissociation of micelles and formation of other association structures in contact with the gastrointestinal fluid. In this study, we demonstrated the effect of the fed-state intestinal fluid (FeSSIF) upon characteristics of bare and quercetin (QCT)-loaded pluronic 123 (P123) micelles. Characterizations were performed using dynamic light scattering (DLS), 1H NMR, heteronuclear single-quantum coherence (HSQC), two-dimensional 1H-1H nuclear Overhauser effect spectroscopy (2D-NOESY), and diffusion-ordered spectroscopy (DOSY). In the case of bare micelles, we found copolymer-bile salt mixed aggregates without any noticeable change in size. DOSY data revealed that lecithin formed a separate aggregate in the FeSSIF. Complete micellar solubilization of QCT could be verified by the disappearance of its proton signals. At higher dose levels, the diffusion coefficient of micelles increased in the FeSSIF. We speculate that QCT-induced hydrophobicity and availability of FeSSIF components would have driven the formation of small-sized mixed assemblies. On the contrary, the diffusion coefficient of micelles decreased with an increase in the QCT load in the medium devoid of FeSSIF components. We deduce that lack of lecithin and bile salts precluded the formation of mixed assemblies in this case, and therefore, micelles turned heavier at higher QCT loads. Such insights on self-assembled formulations can be valuable in improving their biological performance.

Nutritional ecology of a predatory stink bug: A comparative analysis of nutrient acquisition from two prey species and an artificial diet

The nutritional content of prey plays a pivotal role in shaping the predatory behavior and effectiveness of natural pest control agents like Eocanthecona furcellata. We assessed the biological performance and life history of E. furcellata on three diets, larvae of Spodoptera frugiperda, larvae of Tenebrio molitor, and an artificial diet. We also analyzed their nutritional content and quantified consumption and nutritional intake by E. furcellata. The three diets differed substantially in water, protein, and fat content. The moisture content of T. molitor larvae was significantly lower (35.0 ± 0.3 %) than that of S. frugiperda larvae (61.0 ± 0.6 %) or the artificial diet (88.7 ± 0.1 %). Female E. furcellata obtained 8.3 mg of protein per day feeding on S. frugiperda, significantly more than on T. molitor (2.4 mg) or the artificial diet (0.4 mg). 15-day fecundity ranged from 140.2 (±9.3) eggs on S. frugiperda, to 103.3 (±4.8) eggs on T. molitor, and 75.1 (±7.1) eggs on the diet. Our study provides insights into the nutritional ecology of E. furcellata and ways to improve the breeding of this beneficial species for augmentation in agricultural applications.

Effects of rainfall on parasitism and survival of Telenomus remus, an egg parasitoid of fall armyworm

Telenomus remus is an egg parasitoid of Spodoptera species, including the major agricultural pest Spodoptera frugiperda. Climatic factors are closely related to the development and population dynamics of such parasitoids. However, the effects of rainfall on the biological performance of this wasp have not be studied. Here, we modeled the effects of different intensities of rainfall (control: 0, light rain: 5.0, moderate rain: 10.2, and torrential rain: 42.8 mm/h; falling over a 30 min period) on the parasitism rate, developmental time, and survival of T. remus on eggs of S. frugiperda. We assessed the effect of rainfall exposure on both T. remus adults and on parasitized S. frugiperda eggs. Simulated rainfall resulted in a notable decline in the number of hosts parasitized by T. remus adults for up to 12 h following rainfall, but the parasitism rate returned to normal within one day after rain ceased. Torrential rain reduced immediate (within 24 h) survival of adults of T. remus females, but there was no subsequent effect on adult survival after rain ceased. When parasitized host eggs were exposed to rain events, some eggs were dislodged. Moderate or torrential intensity rainfall dislodged 12 and 44% of S. frugiperda eggs from maize leaves. For T. remus eggs exposed to rain that were not dislodged, the probability of reaching adulthood and successfully emerging was negatively correlated with rainfall intensity. However, for all levels of rainfall intensity, the survival of eggs that were not dislodged was greater than those that were dislodged. These findings suggest farmers should avoid releasing natural enemies when rainfall occurs or is forecast, and they should make supplemental releases after unanticipated rainfall occurs immediately after releases.

Enhancing collaboration quotient in crop protection research and development - multi-disciplinary cross-learning to promote sustainability.

After a decade of consolidation with a focus on top market players, global crop protection research is undergoing a paradigm transition by integrating new cutting-edge technologies originating from established and new research organizations. Both development and distribution organizations are working together to make these innovations available to the global farming community. For this, excellent crop protection products are in demand, creating value for farmers and society with superior biological performance and at the same time very high product safety profiles. However, the enormous constraints researchers are exposed to, require the discovery and development of innovative solutions in the shortest possible time frame, while embracing environmental, social, and governance (ESG) objectives as the new normal across the whole industry. Today, fully integrated research and development (R&D) companies are addressing the whole plethora of agrochemistry, biologicals and plant health products, organic farming, seeds and traits, new application technologies, digital farming, improved diagnostics, artificial intelligence (AI), and machine learning (ML)-based approaches. However, there is still a strong need for further innovations from a wide range of sources. Targeted collaboration across various market players is key to combining required activities. This mandates a high level of discipline to frame the proprietary and knowledge environment across the industry. Furthermore, the cooperation of industry and academia will enable an extra push for innovation in the crop protection landscape. Current trends and suggestions are given of how collaborations need to be framed within the industry as well as within the public sector. © 2024 Society of Chemical Industry.

Comprehensive review of biological response, alloy design, strengthening mechanisms, performance evaluation, and surface modifications of titanium alloys for biomedical applications

Comprehensive review of biological response, alloy design, strengthening mechanisms, performance evaluation, and surface modifications of titanium alloys for biomedical applications

Metabolic pathways and gene expression changes in Amblyseius orientalis Ehara (Acari: Phytoseiidae): The role of host plant nutrients in predator-pest dynamics

Amblyseius orientalis Ehara (Acari: Phytoseiidae) is one local predatory mite in China that has high potential for controlling Polyphagotarsonemus latus, a globally important pest to many vegetables and crops. To further evaluate the control potential of A. orientalis on different host plants against P. latus, we selected bean, cucumber, and pepper as host plants to feed P. latus, and then to feed A. orientalis. It was found when the prey P. latus fed on cucumber leaves, development of A. orientalis was the slowest, with the lowest egg production and overall poor biological performance. When A. orientalis was fed with prey hosted on cucumber and the other two plants, there were 119 differentially expressed organic compounds. The differentially metabolites were significantly enriched in the pentose phosphate pathway and carbon metabolism pathway. Further transcriptomic analysis of A. orientalis revealed 36 differentially expressed genes. Among these genes, 20 were annotated in 17 pathways in KEGG, with significant enrichment in hippo signaling pathway-fly and polysaccharide degradation pathways detected. These results indicate that the development and reproduction of A. orientalis are significantly poorer when feeding on P. latus, leading to a marked decline in amino acids, sugars, lipids, and organic compounds in A. orientalis. Additionally, there are 36 genes with consistently different expression patterns in A. orientalis when comparing cucumbers to the other two host plants. This study is an initial attempt to unravel the biological mechanisms of how nutritional substances might affect biology of natural enemies through the food chain.

Ionic substitution through bredigite doping for microstructure and performance adjustment in DLP 3D-printed TPMS porous HA bone scaffolds

ABSTRACT Hydroxyapatite (HA) is widely used in bone scaffold development, but still faces problems of forming difficulty, slow degradation, and limited biological performance. In this study, triply periodic minimal surface (TPMS) porous HA scaffolds were prepared using desktop-level DLP and then doped with bredigite (BR) to enhance their performance through ion substitution to adjust microstructure. The DLP-prepared scaffolds displayed intricate curved surface porous structure, and their micro-porosity decreased while grain size increased with sintering holding time. During sintering, Mg2+ from BR substituted Ca2+ in HA, forming new secondary phases, which slightly decreased grain size while significantly increased micro-porosity. These factors slightly reduced mechanical properties while significantly enhanced degradation. The rapid release of inorganic active ions from BR and new phases enhanced the biomineralization and cell response. This study demonstrated the potential of using desktop-level DLP to construct complex porous ceramic scaffolds and using ion substitution to modulate their microstructure and performance.

Optimizing α-tricalcium phosphate bone cement composite formulations: The critical role of bioactive glass particle size

Calcium phosphate cements (CPCs) have been extensively utilized as bone grafting material due to their inherent osteoconductive properties, although they often lacked sufficient biological performance for effective bone healing at the defect site. Incorporating mesoporous bioactive glass (MBG) into CPCs offers a solution by improving porosity, promoting degradation and increasing the available surface area. In the scope of this study, we integrated MBG into CPCs and assessed the impact of varying MBG particle sizes (<20 µm, <38 µm, <100 µm) on the setting characteristics, microstructure, mechanical strength, and preliminary cell response of CPCs. Investigations revealed that < 20 µm MBG particles significantly improved the setting characteristics and compressive strength of CPCs, while < 38 µm particles promoted degradation and ion release, facilitating apatite formation. MBG incorporation was found to promote microstructural homogeneity and facilitate apatite formation, with particle size directly affecting these outcomes. Biocompatibility assessments indicated no cytotoxic effects, supported by the favorable cellular responses (> 92 % viability compared to control group). These findings underscore the critical impact of MBG particle size on developing advanced CPCs for biomedical applications, guiding future design and optimization strategies.

Mimicking Osteoid 3D Porous Dense Microfiber Silk Fibroin Embedded Poly(vinyl alcohol) Scaffold for Alveolar Ridge Preservation

Abstract Alveolar ridge loss presents difficulties for implant placement and stability. To address this, alveolar ridge preservation (ARP) is required to maintain bone and avoid the need for ridge augmentation using socket grafting. In this study, a scaffold for ARP was created by fabricating a 3D porous dense microfiber silk fibroin (mSF) embedded in poly(vinyl alcohol) (PVA), which mimics the osteoid template. The research utilized a freeze-thawing technique to create a mimicked osteoid 3D porous scaffold by incorporating different amounts of mSF into the PVA, namely, 1%, 3%, 5%, and 7%. Subsequently, a 3D profilometer machine and a scanning electron microscope (SEM) were employed to examine the morphology and size of the mSF and the mimicked osteoid 3D porous scaffold in all groups. Thermal characteristics and crystalline structure were analyzed before assessing the water contact angle, swelling behavior, degradation, and mechanical properties. The experiment evaluated the biological performance of the mimicked osteoid 3D porous scaffold by examining the efficacy of osteoblast cell adhesion, proliferation, viability, protein synthesis, alkaline phosphatase (ALP) activity, and calcium synthesis. Finally, the ability of osteoblast cells to regulate the osteoid matrix deposition on the osteoid 3D porous scaffold was assessed by mimicking the dynamic bone environment using rat mesenchymal stem cells (RMSC). The findings suggest that incorporating mSF into PVA enhances the interconnective pore size, crystalline structure, and thermal behavior of the mimicked osteoid 3D porous scaffold. The hydrophilicity of PVA decreased with an increase in the proportion of mSF, while a higher proportion of mSF resulted in increased swelling and mechanical characteristics. Incorporating a greater proportion of mSF, specifically 5% and 7%, led to a reduced rate of degradation. The addition of 5% mSF to the PVA 3D porous scaffold resulted in remarkable biological properties and excellent osteoconductive activity.

DNAR-01. THERAPEUTIC APPLICATIONS OF MESENCHYMAL STEM CELL LOADED WITH GOLD NANOPARTICLES FOR REGENERATIVE MEDICINE

Abstract In the present study, the various concentrations of AuNP (1.25, 2.5, 5, 10 ppm) were prepared to investigate the biocompatibility, biological performances and cell uptake efficiency via Wharton’s jelly mesenchymal stem cells and rat model. The pure AuNP, AuNP combined with Col (AuNP-Col) and FITC conjugated AuNP-Col (AuNP-Col-FITC) were characterized by Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and Dynamic Light Scattering (DLS) assays. For in vitro examinations, we explored whether the Wharton’s jelly MSCs had better viability, higher CXCR4 expression, greater migration distance and lower apoptotic-related proteins expression with AuNP 1.25 and 2.5 ppm treatments. Furthermore, we considered whether the treatments of 1.25 and 2.5 ppm AuNP could induce the CXCR4 knocked down Wharton’s jelly MSCs to express CXCR4 and reduce the expression level of apoptotic proteins. We also treated the Wharton’s jelly MSCs with AuNP-Col to investigate the intracellular uptake mechanisms. The evidence demonstrated the cells uptake AuNP-Col through clathrin-mediated endocytosis and the vacuolar-type H+-ATPase pathway with good stability inside the cells to avoid lysosomal degradation as well as better uptake efficiency. Additionally, the results from in vivo examinations elucidated the 2.5 ppm of AuNP attenuated foreign body responses and had better retention efficacy with tissue integrity in animal model. In conclusion, the evidence demonstrates that AuNP shows promise as a biosafe nanodrug delivery system for development of regenerative medicine coupled with Wharton’s jelly MSCs.

CNSC-02. ANTICANCER ABILITY OF THE BERBERINE TO PROMOTE THE APOPTOSIS EFFECT AND ATTENUATE THE ROS GENERATION CAPACITY ON DBTRG BRAIN CANCER CELLS

Abstract Abstract In this research, berberine (BB), and its effect on the biological performance of DBTRG brain cancer cells and normal endothelial cells (EC) was investigated. Firstly, the DBTRG cancer cell and EC cell were cultured with different concentrations of BB (0.5, 1, 5 and 10 μg/ml), and it was confirmed that BB significantly reduced the proliferation of DBTRG cancer cells. However, there is no significant toxic effect on EC cells. The results of cell cycle analysis confirmed that BB significantly induced DBTRG cancer cell undergo apoptotic effect in a dose dependent manner. The assessment of cell migration behavior showed that BB significantly inhibited cell migration in DBTRG cancer cell, but not in BAEC as well as attenuated the matrix metalloproteinase 2/9 (MMP2/9) in a dose dependent manner. Furthermore, the reactive oxygen species (ROS) generation capacity among DBTRG cancer cell, EC cell and macrophages (Raw 264.7). It was demonstrated that BB was prominently decreased the ROS generation of DBTRG instead of EC or Raw264.7 cell. Moreover, the pro-inflammatory cytokines of TNF-α, IL-1β and IL-6 were significantly inhibited by BB in a dose dependent manner of DBTRG brain cancer cell. As mentioned above, it was demonstrated that bioactive BB molecules is potential for anti-brain cancer drugs may via anti-immune response and anti-oxidative generation capacity for brain cancer therapy. BB biomolecules may target for DBTRG cell which cannot cause inevitable toxic damage to the normal EC cell. Altogether, the promising findings of BB biomolecule on DBTRG cancer cell suggest that BB may be a good candidate of anticancer drug or adjuvant for the treatment of human brain cancer. Key words: berberine, DBTRG brain cancer, anti-immune response, anti-oxidative generation

Biological variation and analytical performance specification study of erythrocyte and related parameters

Objective: To study biological variation (BV) and analytical performance specifications (APS) of 15 erythrocyte and related parameters. Methods: Sixty healthy participants from Beijing Hospital were prospectively recruited for the study, from July to December, 2023, including 30 males [aged (41.3±11.9) years] and 30 females [aged (40.3±12.4) years]. The study was designed based on the Biological Variation Data Critical Appraisal Checklist and the characteristics of erythrocyte detection. Whole blood samples were collected 10 times at 2-week intervals during 20 weeks. All samples were tested in duplicate using Mindray BC-7500 hematology analyzer and its accompanying reagents. Within-subject biological variation (CVI) and between-subject biological variation (CVG) were estimated by the nested ANOVA method. The BV data in this study were compared with the BV data of the European Database of Biological Variation. APS, reference change value (RCV) and index of individuality (II) were calculated. Results: The CVI for 15 parameters ranged from 0.49% to 86.46%, and the CVI data for red cell distribution width (RDW)-CV, RDW-SD, reticulocyte (RET) percentage, RET count, reticulocyte hemoglobin content (RHE), medium fluorescence reticulocyte (MFR) and high fluorescence reticulocyte (HFR) were significantly higher in females than in males (all P<0.05). The CVG ranged from 1.27% to 100.79%, and the CVG data for HFR were significantly different between genders (P<0.05). The CVI data for red blood cell (RBC), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC) and RHE in this study were lower than those recommended by the European database. The derived indicators of most parameters were influenced by gender. The II values for all parameters were<1.4, where the II values of MCHC and HFR were between 0.6 and 1.4; the II values for the remaining 13 parameters were<0.6. Conclusions: A BV study protocol for erythrocyte parameters is designed. When the reference intervals differ between genders, BV data should be calculated separately and the lower BV data are recommended for calculating APS; the RCV should be set separately for each gender.

Impacts of UV-filter pollution and low pH: Sperm and adult biomarkers in the mussel Mytilus galloprovincialis in a multi-stressor context.

In an era of unprecedented environmental changes, understanding the combined effects of multiple stressors on species' performance is urgent. The increasing UV-filter incorporation in daily-life products raises concerns about their potential impact on marine-coastal environments upon release. As stressors rarely act alone, global change-induced factors, such as ocean acidification (OA), can amplify ecological hazards promoted by contaminants in coastal realms. This study investigated the combined impacts of UV-filters 4-methylbenzylidene camphor (4-MBC) and benzophenone-3 (BP-3), at ecologically relevant concentrations (1 and 10 µg/L), under two target pH levels (8.2 and 7.7, reflecting a ∆pH of 0 and -0.3 relative to the average pH at the sampling site), on the biological performance and male reproductive health of the mussel Mytilus galloprovincialis. Using sperm and adult assays alongside a multi-biomarker approach, the study revealed that pH was the primary driver of the decline in mussel physiological and biochemical performances, further intensifying UV-filters' impacts. While sperm cells showed adaptive responses to low pH conditions alone, characterized by reduced lipid peroxidation (LPO) levels and superoxide anion overproduction, adult mussels experienced more pronounced effects, particularly under simultaneous exposure to low pH and UV-filters. Specifically, the adults exhibited distinct bioconcentration patterns under low pH, enhanced cellular metabolic activity and energy-demand compensatory processes, activation of biotransformation pathways, and regulation of antioxidant defenses. Given the ecological and socio-economic importance of M. galloprovincialis and its demonstrated vulnerability to these stressors, these findings highlight the need for further studies on potential transgenerational impacts and evolutionary implications for mussel populations.

Redevelopment of natural eugenol as potential pesticidal resource: New insights into synthesis and antifungal evaluation of eugenol-derived Schiff bases with reactive oxygen species behavior

Natural products have ancient history as fascinating sources of pharmaceuticals, agrochemicals as well as NPs-derived drug/pesticide innovation. Its diversiform biological performance and skeleton diversity enable to fill the drug/pesticide discovery pipeline in response to the growing innovation demand. Eugenol, a naturally occurring phenolic compound from plant Eugenia caryophyllata, have been attracting attention in agricultural application. To further extend its value-added utilizations in agricultural application and elucidate the underlying molecule mechanism, the 35 of novel eugenol-derived Schiff bases were herein skillfully prepared by means of natural-products modification strategy. Interestingly, the antifungal activity results indicated that the optimal antifungal molecule was A10, affording an EC50 of 0.850 μg/mL toward Botryosphaeria dothidea (B. d.), which was superior to those of parent eugenol (EC50 > 100 μg/mL) and ferimzone (EC50 > 100 μg/mL). It was illustrated that introduction of Schiff base scaffold into natural eugenol contributed to enhance the antifungal performance. Furthermore, a series of bioassays showed the antifungal behavior of compound A10, which had a powerful disruptive effect on the membrane by triggering reactive oxygen species production in the mycelium. Taken together, this study redeveloped natural eugenol as potential antifungal candidates to control fungal infections by triggering reactive oxygen species production.

Impact of corn shredlage and crabtree-negative yeast on silage quality and rumen fermentation characteristics

The physical attributes of corn silage are enhanced by shredlage (SHR), while there is a rising interest in boosting its biological performance. This study aimed to assess and compare the impact of both the chopping method and different yeast strains on ensilage quality including the in vitro evaluation of corn silage. Both types of corn, including chopped and shredded, were harvested on the same day from the same field where the same corn hybrid (Suwan 5) was grown. Subsequently, whole-corn plants were fermented with additives. A 2 × 5 Factorial completely randomized design was employed, where factor A represents corn chopped (CON) and corn shredded (SHR), and factor B represents the additives: no additives, molasses + urea (M + U), M + U + Candida tropicalis KKU20, M + U + Pichia kudriavzevii KKU20, and M + U + saccharomyces cerevisiae. The results demonstrated that SHR fermentation with M + U and yeast significantly increased in vitro dry matter degradability (IVDMD) and organic matter degradability (IVOMD). Specifically, at 4 h post-incubation, the addition of Crabtree-negative yeast led to a 5.8% increase in total volatile fatty acids (TVFA) compared to the Crabtree-positive yeast group (P < 0.01). The C2 (acetic acid) + C4 (normal butyric acid and isobutyric acid): C3 (propionic acid) ratio showed a significant decrease without additives, but P. kudriavzevii KKU20 led to the highest ratio and methane production (P < 0.01). Based on this study, it could be concluded that SHR harvesting led to higher digestion efficiency in the rumen. The use of M + U + yeast also demonstrated uncertain effects on rumen fermentation efficiency, and the inclusion of P. kudriazevii KKU20 may potentially reduce rumen fermentation efficiency when used with corn silage.

Biological performance of Bollgard II® Bt-resistant vs susceptible population of pink bollworm, Pectinophora gossypiella (Saunders) on non-toxic diet

BackgroundThe pink bollworm, Pectinophora gossypiella (Saunders), is a devastating global pest of cotton that has caused substantial economic damage to Bt Bollgard-II® cotton plants in recent years due to the evolution of Bt resistance. The associated fitness cost is assumed to be one of the factors delaying the development of resistance against Bt transgenic crops. Hence, the present study was undertaken to assess the biological performance of pink bollworms by comparing the life history and demographic parameters of a resistant (Field-R) and susceptible (Lab-S) population.ResultsProlonged larval duration (23.40 days in Field-R vs 18.80 days in Lab-S population), total life cycle (male = 50.00 vs 42.80 days; female = 53.60 vs 46.20 days), reduced fecundity (100.60 vs 154.20 eggs/female) and fertility (88.00 vs 138.00 fertile eggs/female) was observed. The demographic parameters indicated a significant reduction in the net reproductive rate (184.27 vs 276.72), innate capacity for increase in number (0.11 vs 0.15), finite rate of increase in number (1.12 vs 1.16 female progenies produced/female/day), weekly multiplication rate (2.16 vs 2.86), potential fecundity (545.06 vs 634.11 eggs), number of hypothetical F2 females (33 955.65 vs 76 572.41), but longer mean length of generation (47.54 vs 37.74 days) and population doubling time (6.30 vs 4.62 days) in Field-R compared with Lab-S population. A stage-specific life table demonstrated the differences in survival rates between susceptible and resistant populations at various life stages, with the resistant population having higher generation mortality (0.22 vs 0.19).ConclusionsThe study confirms the involvement of fitness costs associated with Bt resistance in P. gossypiella. Despite reduced reproductive fitness, the resistant population tried prolonging the larval stage as a compensatory mechanism to repair the damaged host tissues due to Bt intoxication and for accumulation of enough nutrient reserves for normal pupation and adult emergence. Presence of a high proportion of double Bt-resistant larvae in the field coupled with continued noncompliance with refug planting certainly favours the flaring up of this monophagous pest despite the observed fitness costs. The resistance cannot be effectively reversed unless suitable alternative management strategies are deployed.