Seaweed Extracts Research Articles

Designing sustainable antioxidant and anti-inflammatory ingredients from seaweeds for functional gummies

Atlantic wakame (AW) and sea lettuce (SL) are edible seaweeds commonly produced in Asia and Europe, typically consumed as fresh or dried biomass. Because of the short shelf life, developing new post-harvest treatments, such as the extraction of bioactive compounds, is essential for establishing reliable macroalgae supply chains for food applications. This study aims to develop a sustainable and functional seaweed-based food ingredient rich in bioactive compounds for functional food applications. The results indicated that ultrasound-assisted extraction using 70% ethanol for 10 minutes was optimal for both SL (410±23 mg of gallic acid equivalent [GAE] per kg) and AW (666±63 mg GAE/kg). Both extracts exhibited chemical antioxidant activity and inhibited the protection of human plasma against chemically induced oxidation. SL extract did not exhibit free radical scavenging activity (DPPH). Importantly, no cytotoxicity (IC50>250 µg/mL) was observed in human-derived THP-1, HUVEC, HT-29, and HepG2 cell lines, ensuring the relative safety of these extracts for potential food technology applications. AW and SL extracts (100 µg/mL) reduced intracellular reactive oxygen species generation in lipopolysaccharide (LPS)-challenged THP-1 cells by 66% and 30%, respectively, highlighting the higher antioxidant activity of AW extract. AW and SL extracts did not modulate TNF-α and IL-6 secretion to show anti-inflammatory activity. Gummies infused with AW and SL extracts had a higher total phenolic content than commercial products, but their antioxidant activity was lower. Sensory evaluation revealed that gummies containing seaweed extracts received lower scores for colour, taste, overall impression, and purchase intention than those without extracts.

Use of Marine Microorganisms in the Production of Bioactive Materials for the Pharmaceutical Industry

The global pharmaceutical industry is constantly looking for new resources that can be used to develop bioactive ingredients to produce more effective and innovative medicines. One resource that has attracted the attention of researchers is marine microorganisms (UGM, 2017; Wiganti, 2022). The ocean, which covers more than 70% of the Earth's surface, is an ecosystem rich in biodiversity, including microorganisms that are unique and rarely found in terrestrial environments. This research aims to explore and identify marine microorganisms that have potential in the production of bioactive materials for pharmaceutical applications. Based on the results of this study, only Extract I showed significant inhibition against Staphylococcus aureus, while Extract II had almost no inhibition. Table 2 shows the results of the study indicating that the inhibition of seaweed extracts was absent. Gracillaria sp. seaweed extracts evaporated through a rotary vacuum evaporator and seaweed extracts evaporated through an oven had no inhibition. This study showed that bioactive compounds prepared through extraction using vacuum evaporator had greater inhibition of Staphylococcus aureus. This suggests that marine microorganisms can be a source of bioactive ingredients for the pharmaceutical industry.

Effect of Seaweed Extract and Humic Acid Treatment on the Phenological and Yield Characteristics of Guava (Psidium guajava L.)

Aim: The main aim of this study was to evaluate the impact of seaweed and humic acid treatment at different doses on the phenological characteristics and yield of guava. Study Design: Randomized block design. Place and Duration of Study: A field experiment was conducted from December 2023 to July 2024 to assess the impact of bio-stimulants on the phenological and yield traits of guava (var. Arka Kiran) in the Poongunam village, Chengalpattu Dist, Tamil Nadu, India. Methodology: The experiment followed a Randomized Block Design with eight treatments: T₁ - Absolute control, T₂ - Water Spray, T₃ - 1% Seaweed Extract, T₄ - 1.5% Seaweed Extract, T₅ - 2% Seaweed Extract, T₆ - 1% Humic Acid, T₇ - 1.5% Humic Acid, and T₈ - 2% Humic Acid, each replicated three times. Results: Results showed that 2% Seaweed Extract (T₅) significantly improved flower retention (7.55 flowers per shoot), reduced the duration from flowering to fruit set (12.47 days), and shortened the time from fruit set to harvest (121.56 days). T₅ also led to the highest fruit set (68.65%), lowest fruit drop (48.72%), largest fruit weight (150.02 g), and greatest yield (13.35 kg/tree). Humic Acid at 2% (T₈) also improved fruit set (64.32%), fruit drop (49.54%), and yield (12.34 kg/tree), but was less effective than Seaweed Extract. Conclusion: This study demonstrates the potential of Seaweed Extract as a powerful bio-stimulant to enhance guava production, offering a sustainable alternative to traditional chemical treatments.

Effect of Organic Nutrients and Zinc Biofortification on Growth and Yield of Sponge Gourd (Luffa cylindrica L.) CV. Mahy Harita

A field experiment was carried out at Orchard, Department of Horticulture, Annamalai University, Faculty of Agriculture, TamilNadu during 2023-2024. The experiment was laid out in RBD with fifteen treatments in three replications. The organic manures used in the experiment were farm yard manure (25 t ha-1) and enriched manure (1 t ha-1) as soil application along with consortium biofertilizer (2 kg ha-1) and foliar application of biostimulants viz., panchagavya (3%), sea weed extract (3%) and effective microbial inoculants (2%). The zinc in the form of Bacillus subtilis @ 10 and 20g was applied as soil application. The results of the experiment revealed that the growth parameters viz., vine length, number of leaves, leaf length, leaf breadth and leaf area were recorded the highest in the treatment that received the application of farmyard manure 25 t ha-1combined with panchagavya (3%) as foliar application and Bacillus subtilis @ 20g. The yield attributes viz., the highest number of fruits plant-1, fruit length, fruit girth, fruit weight, fruit yield plant-1 and the zinc uptake in fruit were registered in the treatment which received the application of enriched manure @1 t ha1 combined with panchagavya (3%) as foliar application and Bacillus subtilis @ 20g (T11) respectively.

Seaweed extracts: enhancing plant resilience to biotic and abiotic stresses

Seaweeds are a natural marine resource containing many bioactive compounds such as amino acids, lipids, carbohydrates, proteins, phytohormones, and antimicrobial compounds. Since ancient times, seaweeds have been used in various sectors, including medicine, food, and the cosmetic industry. Currently, seaweeds are a promising alternative to reduce the application of harmful chemicals in agriculture. Seaweed and its derived products have been utilized for plant growth promotion, immunity enhancement, and the reduction of biotic and abiotic stresses. In the current global scenario, synthetic fertilizers and chemical pesticides are commonly used to increase agricultural crop production to meet the growing demands of the world population. However, these chemicals pose significant threats to the health of people, livestock, plants, soil, and the entire environment. In contrast, seaweed-based products are emerging as a newer option for stress mitigation and reduction, offering an alternative to synthetic chemicals. This article explains the use of seaweed extracts to increase the tolerance of plants to biotic and abiotic stresses. We also address the functions of various bioactive compounds present in seaweed extracts and the mechanisms by which they promote plant growth and induce defense against different stresses.

The Synergistic Impact of a Novel Plant Growth-Promoting Rhizobacterial Consortium and Ascophyllum nodosum Seaweed Extract on Rhizosphere Microbiome Dynamics and Growth Enhancement in Oryza sativa L. RD79

This study investigated the combined effects of novel plant growth-promoting rhizobacteria (PGPR)—Agrobacterium pusense NC2, Kosakonia oryzae WN104, and Phytobacter sp. WL65—and Ascophyllum nodosum seaweed extract (ANE) as biostimulants (PGPR-ANE) on rice growth, yield, and rhizosphere bacterial communities using the RD79 cultivar. The biostimulants significantly enhanced plant growth, shoot and root length, and seedling vigour; however, seed germination was not affected. In pot experiments, biostimulant application significantly increased the richness and evenness of bacterial communities in the rhizosphere, resulting in improvements in rice growth and yield, with increases in plant height (9.6–17.7%), panicle length (14.3–17.9%), and seeds per panicle (48.0–53.0%). Notably, biostimulant treatments also increased post-harvest soil nutrient levels, with nitrogen increasing by 7.7–19.2%, phosphorus by 43.4–161.4%, and potassium by 16.9–70.4% compared to the control. Principal coordinate analysis revealed distinct differences in bacterial composition between the tillering and harvesting stages, as well as between biostimulant treatments and the control. Beneficial bacterial families, including Xanthobacteraceae, Beijerinckiaceae, Acetobacteraceae, Acidobacteriaceae, and Hyphomicrobiaceae, increased in number from the tillering to harvesting stages, likely contributing to soil health improvements. Conversely, methanogenic bacterial families, such as Methanobacteriaceae and Methanosarcinaceae, decreased in number compared to the control. These findings highlight the dynamic responses of the rhizosphere microbiome to biostimulant treatments and underscore their potential benefits for promoting sustainable and productive agriculture.

Mitigating excessive heat in Arabica coffee using nanosilicon and seaweed extract to enhance element homeostasis and photosynthetic recovery.

Global warming-related temperature increases have a substantial effect on plant and human health. The Arabica coffee plant is susceptible to growing in many places across the world where temperatures are rising. This study examines how nanosilicon and seaweed extracts can improve Arabica coffee plant resilience during heat stress treatment (49.0 ± 0.3°C) by maintaining mineral homeostasis and photosynthetic ability upon recovery. The principal component analysis arrangement of four treatments, nanosilicon (Si), seaweed extract (SWE), Si + SWE, and control (CT), showed each element ratio of magnesium, phosphorus, chloride, potassium, manganese, iron, copper, and zinc per silicon in ambient temperature and heat stress that found influenced upper shoot rather than basal shoot and root within 74.4% of largest feasible variance as first principal component. Magnesium and iron were clustered within the silicon group, with magnesium dominating and leading to a significant increase (p ≤ 0.05) in magnesium-to-silicon ratio in the upper shoot under heat conditions, especially in Si and Si + SWE treated plants (1.11 and 1.29 fold over SWE treated plant, respectively). The SWE and Si + SWE treated plants preserved chlorophyll content (15.01% and 28.67% over Si-treated plant, respectively) under heat stress, while the Si and Si + SWE treated plants restored photosynthetic efficiency (Fv/Fm) better than the SWE treated plant. The concomitant of the Si + SWE treatment synergistically protected photosynthetic pigments and Fv/Fm by adjusting the magnesium-silicon homeostasis perspective in Arabica coffee to protect real-world agricultural practices and coffee cultivation under climate change scenarios.

Optimization of Sargassum bovianum Extraction Techniques for Germination of Wheat, Canola, and Corn Under Different Salinity Stress

Seaweeds are a cheap, eco-friendly, and rich source of plant growth stimulators that can mitigate the adverse effects of salinity stress. This study examined the impact of Sargassum bovianum extracts obtained through different techniques using pressure, heat, and microwave radiations on the germination and growth of wheat, corn, and canola seeds under varying salinity levels (500, 3500, and 6500 µS cm−1). The findings showed that pressure, microwave, and acidic extraction methods were the most effective in extracting polysaccharides, alginate, and nutrients from S. bovianum. Seaweed extract significantly improved the mean germination time (MGT) and germination index (GI) of wheat under high salinity stress and had a positive effect on wheat plumule length (PL) and germination percentage (GP). However, seaweed extract had no significant impact on canola seeds in salinity stress, except for improved canola PL. The PL and seedling vigor index (SVI) of corn were enhanced in low salinity levels, but most treatments reduced PL and SVI in high salinity. This study suggests that using heat, pressure, and microwave techniques for seaweed extraction results in higher polysaccharides and alginate content, leading to improved germination and plant growth, particularly in wheat and canola. These findings can help growers optimize the germination and growth of these important crops.

Physiological and Biochemical Responses of ‘Burlat’ Sweet Cherry to Pre-Harvest Foliar Application of Calcium and Seaweed Extracts

Sweet cherry (Prunus avium L.) is a highly valued fruit, and optimal nutrient management is crucial for enhancing yield and fruit quality. However, the over-application of chemical fertilizers in cherry cultivation leads to environmental issues such as soil degradation and nutrient runoff. To address this, foliar application, a more targeted and eco-friendly fertilization method, presents a promising alternative. This study evaluates the effects of pre-harvest foliar application of calcium (Ca) (150 and 300 g hL−1) and seaweed extracts (75 and 150 mL hL−1), both individually and in combination, on the physiological and biochemical responses of ‘Burlat’ sweet cherry trees. Key physiological parameters, including plant water status, photosynthetic performance, and leaf metabolites, were analyzed. Results show that trees treated with seaweed extracts or with combined Ca and seaweed application had improved water status, higher sugar, starch, and protein content, as well as enhanced antioxidant activity and phenolic content compared to those treated solely with calcium. However, the combined treatment did not significantly enhance overall tree performance compared to individual applications. This study highlights the potential of seaweed-based biostimulants in sustainable cherry production.

Evaluation of Ethanolic Extract of Red Seaweed (Gracilariopsis lemaneiformis) on Growth and Haematological Parameters of Nile Tilapia (Oreochromis niloticus)

ABSTRACTSeaweed is multicellular marine macroalgae that enhances the immunity of aquatic organisms. The study was designed to assess the ethanolic extract (EtOH) extracted from red seaweed (Gracilariopsis lemaneiformis) on Nile tilapia (Oreochromis niloticus) to evaluate growth, immunity and haematological parameters. The EtOH was applied with fish feed in four treatments such as T1‐control (0% EtOH), T2 (5% w/v EtOH), T3 (10% w/v EtOH) and T4 (15% w/v EtOH) each with three replicates. The initial average weight of the fish was 17.53 ± 2.1 g. Results showed that the growth increased gradually with the percentage of red seaweed extract, whereas the mean weight gain was found significantly higher in T4 (51.5 ± 4.2) than in the control. The specific growth rate (%) and survival rate (%) were found higher in T4 at the lowest FCR compared to other treatments (p < 0.05). The blood haemoglobin level of Nile tilapia was higher in T4 (11.5 g/dL) and lowest recorded in T1 (7.5 g/dL). However, the level of blood glucose interacted inversely with blood haemoglobin. The plasma protein level was also varied among the treatments (p > 0.05). The blood parameters, refractive index (RI) and spleen somatic index (SSI) were significantly different among the treatments. The RI of blood plasma and SSI were found to be better in T4 treatment. The research indicated that red seaweed extracts significantly enhanced the growth and boosted the immunity level of Nile tilapia.

Effect of Biostimulants on Plant Growth and Leaf Functional Compounds of Passiflora Plants

The influence of biostimulant treatments on Passiflora species was assessed by observing changes in the growth and leaf functional compounds of plants exposed to humic acids (HAs) and seaweed extracts (SEs) to determine their optimal application doses. Four different concentrations of HA irrigation (0, 144, 192, and 285 mg·L−1 per pot assigned as HI-1, 2, 3, and 4, respectively), HA spraying (0, 96, 128, and 192 mg·L−1 as HS-1, 2, 3, and 4, respectively), SE irrigation (SI-1∼4 at 0, 1, 1.33, and 2 g·L−1 per pot, respectively), and SE spraying (SS-1∼4 at 0, 0.5, 0.67, and 1 g·L−1, respectively) treatments were applied to ‘Tainung No. 1’ and Passiflora suberosa cultivars every week to study their responses in plant growth traits and metabolites. Results show that leaf dry weight (DW) and root DW of ‘Tainung No. 1’ plants under SS-3 and HI-4 treatments, respectively, were significantly increased compared with controls. Both HI-3 and HS-3 treatments remarkably increased vine length, fresh weight (FW), and DW of leaves and shoots in P. suberosa plants compared with controls. Furthermore, ‘Tainung No. 1’ and P. suberosa plants respectively subjected to HI-2 and SS-4 treatments contributed to developing biostimulant applications for obtaining higher total phenol and flavonoid content per plant. Both Passiflora species are recommended for treatment with SS-4 and SE to maximize orientin and isovitexin content, and for all their beneficial applications and sustainable use in agriculture.

Phytochemical analysis, antibacterial and anti-diabetic activity of three different seaweed extracts

Aim: Marine seaweed contains potential phytochemical compounds that could able to cure different health issues in humans naturally. Hence the research was aimed to investigate the antibacterial and in vitro anti-diabetic activity of three different seaweed extracts. Methods: Phytochemical compounds like phenol, flavonoids, tannins and alkaloids were quantitatively identified. Antibacterial activity of the seaweed extracts were determined against five different test bacteria. In vitro anti-diabetic activity of the extracts were investigated based on its inhibition effect on the alpha-amylase and alpha-glucosidase activity. Findings: Phytochemical analysis showed more phenolic and flavonoid content in green and brown seaweed extracts and lesser content in red seaweed extract. Antibacterial activity of green and brown seaweed extracts showed good inhibitory zones against all test bacteria ranging from 22.9 ± 0.57 mm to 24.9 ± 0.57 mm (green seaweed extract) and 17.9 ± 0.57 mm to 21.6 ± 0.75 mm (brown seaweed extract) respectively. In vitro anti-diabetic activity of seaweed on the inhibition of enzymes showed promising results. Among the three types, green seaweed extracts showed maximum inhibition of α-Amylase and α-glucosidase activity of 86.6 ± 0.76 % and 82.9 ± 0.57 % respectively. Conclusion: Findings showed that the phytochemicals present in the methanolic extract of seaweeds attribute positively for different pharmacological properties like antibacterial, anti-oxidant and anti-diabetic activity. Optimizing the production factors would able to commercialize the seaweeds in drug forms and could be used for the treatment of various diseases in humans.

Potential Use of Algae and Seaweed Extracts as Protection Against Peach Leaf Curl

Abstract Plant pathogenic fungi are a major cause of plant diseases, contributing significantly to the global decline in food production. Their proliferation results in substantial crop losses, fruit and vegetable deterioration, reduced food accessibility, and billions of dollars in economic losses annually. While synthetic chemical fungicides are commonly used to combat fungal diseases, their environmental impact is concerning. Marine algae provide a sustainable alternative, offering diverse compounds with industrial applications and presenting an eco-friendly solution. Taphrina deformans is responsible for peach leaf curl, a widespread disease in peach trees that can severely impact crop productivity and tree lifespan. Seaweeds and algae, encountering various biological interactions and extreme abiotic conditions, have evolved defense mechanisms, including the production of biologically active substances. In our study, we investigated the efficacy of water extracts from six algae (Nannochloropsis sp., Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira weissflogii, Tisochrysis lutea, Chlorella vulgaris), four seaweeds (Palmaria palmata, Chondrus crispus, Ascophyllum nodosum), and one cyanobacterium (Arthrospira platensis) at two different concentrations (1% and 3%) in suppressing the outbreak of peach leaf curl disease in vivo on peach trees. The spray was applied twice in spring just before budbreak. Algae and seaweed extracts showed significant suppression of peach leaf curl outbreaks on peach trees compared to controls. Following the application of water extract of Chlorella vulgaris at both concentrations, the lowest incidences of symptomatic disease expression were observed (1.00 ±0.00% and 0.25 ±0.50%). Algae and seaweed extracts demonstrate potential in controlling leaf curl disease in peach trees.

Synergistic Effect of Organic Inputs on the Morphophysiological Traits of Sweet Basil (Ocimum basilicum L.)

The present investigation was conducted from 2023 in Chengam, Tiruvannamalai district. The objective was to evaluate the impact of various organic treatments on the growth and yield characteristics of sweet basil (Ocimum basilicum L.). The experiment was carried out is Randomized Block Design with ten treatments and replication thrice. Among the ten different treatments applied, the combination of FYM @ 25 t ha⁻1 + VC @ 2.5 t ha⁻1 + Seaweed extract @ 2% (T9) consistently outperformed other treatments. This treatment significantly enhanced growth characteristics viz., plant height (35.01, 60.33, 86.71 and 110.34 cm), number of leaves plant-1(291.34, 540.56, 850.41 and 1010.66), leaf area (482.33, 1673.20, 3581.23 and 4468.67 cm²) and leaf area index (0.65, 1.33, 2.32 and 3.23), number of primary branches plant-1 (21.45, 25.37, 32.17 and 39.46) and secondary branches plant-1 (64.72, 76.45, 96.56 and 109.34), plant spread (north -south) (25.32, 33.39, 40.26 and 50.38 cm), plant spread (East- west) (40.56, 55.89, 65.47 and 71.45 cm), at 30, 60, 90 and 120 DAT. The findings indicate that the integration of organic inputs of treatment, T9 (FYM @ 25 t ha⁻1 + VC @ 2.5 t ha⁻1 + Seaweed extract @ 2%) is highly effective in optimizing the growth of sweet basil.

Influence of Zinc Oxide Nanoparticles (ZnONPs), Seaweed Extract and Microbial Inoculation with Rhizobium on Faba Bean Nodulation, Yield, and Quantity

Influence of Zinc Oxide Nanoparticles (ZnONPs), Seaweed Extract and Microbial Inoculation with Rhizobium on Faba Bean Nodulation, Yield, and Quantity

Effects of green seaweed (<i>Ulva onhoi</i>) on the reproductive development of tomato (<i>Solanum lycopersicum)</i> plants

Algae-derived products have great potential as crop biostimulants due to their multiple beneficial effects at different stages of plant development. Green seaweeds of the genus <i>Ulva</i> are well suited for this purpose because they are widely distributed and grow rapidly in a wide range of conditions. In this study, a greenhouse experiment was conducted to evaluate the effects of dry seaweed powder (DSP) and liquid seaweed extract (LSE) of <i>Ulva ohnoi</i> on the reproductive development of tomato plants. The experiment included three treatments: 1) plants treated with 5 g of DSP, 2) plants treated with 250 mL of LSE, and (3) control plants (without algae). The reproductive parameters, chlorophyll content, and mineral composition were measured during the flowering and early fruiting periods. The application of DSP was the most effective treatment in promoting early flowering and significantly increased the number of buds (103%), flower clusters (55%), flowers (61%), and fruits (45%) per plant. Furthermore, the DSP-treated plants exhibited an enhancement in the levels of chlorophyll and nutrients in the plants and fruits. The results of the current work show that the application of <i>U. ohnoi</i> in its natural form (dry powder) stimulates the reproductive development of crop tomato. This represents a sustainable and natural alternative to synthetic inputs that growers can incorporate into horticultural production to improve yield attributes.

Enhancing Mango Productivity with Wood Vinegar, Humic Acid, and Seaweed Extract Applications as an Environmentally Friendly Strategy

Enhancing Mango Productivity with Wood Vinegar, Humic Acid, and Seaweed Extract Applications as an Environmentally Friendly Strategy

Influence of spraying nutrients and bioregulators on vegetative growth, flowering and productivity of litchi

Aim: To investigate the influence of nutrients and bioregulators on the vegetative growth, flowering and productivity of Litchi. Methodology: The vegetative growth, flowering and productivity of litchi cv. Bombai was assessed through application of nutrients and bioregulators. Results: The plants receiving treatment with @ 0.5% Borax (T1) showed the highest percentage increase in canopy volume (7.56 %) and plant height (2.46 %) in litchi, outperforming all other treatments. The maximum productivity (38.69 kg per plant) was registered in plants under treatment T2 (0.3% Borax), which was found to be statistically at par (36.68 kg per plant) with plants treated with 0.1% Seaweed extract (T10) . The percentage increase in the plant height, plant spread in East-West and North-South direction, canopy volume, , fruit weight and fruit set capture positive correlation in both PC-1 and PC-2. The total contribution of PC-1 and PC-2 was 60.857 %. Interpretation: Among all the treatments, T2 (0.3% borax) and T4 (ZnSO4 @ 0.4%) treatments proved superior over other treatements with respect to vegetative growth, flowering and productivity parameters in litchi. However, further investigation need to be carried out with combination of these applied nutrients and bioregulators for getting acceptable results. Key words: Bioregulators, Flowering, Growth, Litchi, Nutrients

Nutritional Innovation Using Green Seaweed (Ulva sp.) and Garlic Powder Extracts for White-Leg Shrimp (Litopenaeus vannamei) Challenged by Vibrio harveyi.

This study aimed to determine the antimicrobial effects of ethanolic extracts of Ulva sp. and garlic (Allium sativum) powder ethanolic extracts against Vibrio harveyi in vitro. The stimulatory effects of Ulva sp. extract (UE) and garlic powder extract (GPE) on the growth performance and innate immune responses of white-leg shrimp, Litopenaeus vannamei, and their challenge against V. harveyi infection were also investigated. A commercial shrimp diet (36.1% protein) was enriched with 0.5, 1.0 and 2.0gUE/kg diet and 2, 4 and 6gGPE/kg diet, whereas the control group was free of any supplement. Health juveniles of L. vannamei (average weight 2-3g) were distributed in 21 fiberglass reinforced plastic (FRP) tanks (500-L capacity) at a stocking density of 300 animals/tank to represent each treatment in triplicate. The animals were fed ad libitum on the experimental diets up to satiety four times daily for 60 days. The phytochemical analysis of ethanolic extracts of Ulva sp. and garlic powder evoked their richness of several bioactive compounds showing significant antibacterial activity against V. harveyi. The GPE exhibited a higher inhibition zone than that of the UE. The supplemented diets did not significantly affect weight gain %, final weight, feed conversion ratio, specific growth rate and survival rates of white shrimp compared to those fed on the control diet. Significant increases were observed in total haemocyte count, phagocytosis and phagocytic index of all treatments compared with the control group. There were significant increases in serum total protein, acid phosphatase activity, alkaline phosphatase, lysosomal enzyme activity, phenoloxidase activity and superoxide dismutase activity with offered diets with increasing the levels of ethanolic extracts of Ulva sp. and garlic powder up to 2.0gUE/kg diet and 6gGPE/kg diet, respectively. The ethanolic extraction of Ulva sp. and garlic powder-supplemented diet groups, particularly at treatments of 2.0 and 6gGPE/kg diet, respectively, significantly reduced the shrimp mortality induced by V. harveyi infection when compared with the control group. The net results evoked that ethanolic extraction of Ulva sp. (2.0gUE/kg) and garlic powder (6gGPE/kg diet) enhanced the immune response and disease resistance of the white-leg shrimp, L. vannamei. It is also noted that the GPE is more efficient than the UE in vitro and in vivo investigations.

Effect of Kappaphyscus alvarezii seaweed liquid extract on growth, yield and chemical constituents of Geranium (Pelargonium graveolens l’ Herit. ex Aiton)

The application of seaweed-based fertilizers is an important renewable resource and gaining considerable attention in the present scenario of agriculture and horticulture as organic nutrient input and growth promoters. The present study was conducted to examine the effect of seaweed liquid extract on growth, yield, and chemical constituents of the important aromatic plant geranium. The experiments were conducted in the CSIR-CIMAP, Research Center, Bengaluru (Karnataka, India) during the Rabi season of 2018–2019 and 2019–2020. The results of pooled data over two years revealed that application of Kappaphycus alvarezii seaweed liquid extract (KSWE) along with RDF at a concentration of 15% significantly improved the plant height (71.37 ± 0.69 cm), plant canopy (68.24 ± 1.60 cm), herb yield (42.71 ± 2.45 t ha−1year−1) and oil recovery (0.36 ± 0.02%) as compared over RDF. An account of 23.14% and 23.87% increase in herbage and essential oil yield was recorded over RDF. The functional relationship between herb and oil yield of geranium with different concentrations of seaweed extract applied at different crop stages was strongly correlated (r 2=0.97 and r 2=0.91, respectively). The chemical profile of essential oil reveals that higher amounts of linalool (7.5%) isomenthone (6.65%), geranial (1.29%), geranyl formate (3.81%), and the highest citronellol to geraniol (C:G ratio) ratio of 2.14 was noticed in the treatment which receives 15% KSWE along with RDF. The study clearly exhibits the notable benefits in the performance of geranium with the application of 15% of aqueous seaweed extract from Kappaphyscus alvarezii both in quantitative and qualitative terms.