Spray-dried Preparation Research Articles

Antimalarial Activity of Bidens pilosa Root Extract Co-spray Dried in the Presence of β-Cyclodextrin or Aerosil:Microcrystalline Cellulose Blend

AbstractThe purpose of this work was to evaluate if the antimalarial activity of Bidens pilosa L. root extract could be enhanced by co-spray drying with the pharmaceutical excipients blend of colloidal silicon dioxide:microcrystalline cellulose and β-cyclodextrin. The in vivo antimalarial activity of the products was evaluated in mice infected with Plasmodium berghei. Acute in vivo and in vitro toxicity in S5 HeLa cells were also carried out. B. pilosa L. root extract was lyophilized and used as a control. The spray-dried preparations enhanced the survival of the infected mice compared to the lyophilized crude root extract. The Bidens extract formulations were able to inhibit up to 71% of the growth of the parasite in the lowest tested dose, being about five times more active than the crude extract, thus showing significant partial antiplasmodial activity. The dried preparations did not show signals of toxicity in both the in vitro and in vivo assays. The results showed strong evidence that the co-spray drying of B. pilosa root extract with the selected pharmaceutical excipients might stabilize the bioactive compounds and enhance its antimalarial activity compared with the lyophilized crude extract.

Entrapment of natural compounds in spray-dried and heat-dried iota-carrageenan matrices as functional ingredients in surimi gels.

Two drying methods (spray drying and heat drying) were used to entrap various natural compounds within a matrix of iota-carrageenan. The natural compounds were, namely, collagen hydrolysate (CH), pomegranate polyphenolic extract (PP) and shrimp lipid extract (SL). The resulting dry powders were compared in terms of water solubility, entrapment efficiency, hydrodynamic particle properties, ζ potential and antioxidant properties (ABTS radical scavenging capacity, ferric ion reducing power and Folin-reactive substances). Dry powders and plain compounds were incorporated into squid surimi gels, and after in vitro simulated gastrointestinal digestion (sGID), the residual antioxidant and angiotensin-converting enzyme (ACE)-inhibitory activities were evaluated. All powders showed antioxidant properties, electronegative ζ potential and great entrapment efficiency after rehydration (ranging from ∼70 to 97%). The heat-dried powders were composed of microparticles ranging from 177 to 380 μm resulting in low water solubility (21.6-36.1%), while the average particle size and solubility values of spray-dried preparations were 2.9-13.2 μm and >86%, respectively. In contrast to the plain compounds, the addition of any of the microparticle dried preparations allowed obtaining well-conformed surimi gels. The ACE-inhibitory capacity of the surimi gels after sGID was increased by the addition of any of the compounds studied, but to a lesser extent by their entrapment forms (except with the entrapped SL). The antioxidant activities of gels with the entrapped compounds were even lower than those of gels without bioactives in some cases. In conclusion, the addition of dried microparticles did not increase the biological activity as compared to the plain compounds; however, they were beneficial to ensure adequate gel consistency.

커피 생두 추출물을 이용한 분무건조 분말의 제조 및 물리화학적 품질특성

커피 생두 추출물을 이용한 분무건조 분말의 제조 및 물리화학적 품질특성

Spray-Dried Potato Juice as a Potential Functional Food Component with Gastrointestinal Protective Effects

Background: Peptic ulcer disease, including its complications and functional dyspepsia, are prevalent gastrointestinal diseases, etiopathogenesis of which is associated with mucosal inflammation. Research into new therapeutics capable of preventing or curing gastrointestinal mucosal damage has been steadily developing over past decades. This study was undertaken to evaluate whether a spray-dried preparation of potato juice is applicable for treating and preventing gastrointestinal mucosal damage. Methods: We assessed potential protective effects of spray-dried potato juice (SDPJ) against gut inflammation in the co-culture Caco-2/RAW264.7 system, as well as a gastroprotective activity in a rat model of gastric ulceration. Results: The obtained results indicated that SDPJ down-regulates lipopolysaccharide (LPS)-induced mRNA expression and protein production of proinflammatory cytokines IL-6 and TNF-α in the co-culture model. Moreover, SDPJ provided dose-dependent protection against LPS-induced disruption of intestinal barrier integrity. In rats, five-day pretreatment with SDPJ in doses of 200 mg/kg and 500 mg/kg suppressed HCl/ethanol-induced TNF-α expression in gastric mucosa by 52% and 35%, respectively. In addition, the pretreatment with the lower dose of SDPJ reduced the incidence of ulcers (by 34%) expressed as ulcer index. Conclusion: The spray-dried potato juice appears to be an attractive candidate for ameliorating inflammation-related diseases of the gastrointestinal tract.

Optimization and characterization of spray-dried IgG formulations: a design of experiment approach

BackgroundThe purpose of the present study is to optimize a spray-dried formulation as a model antibody regarding stability and aerodynamic property for further aerosol therapy of this group of macromolecules.MethodA three-factor, three-level, Box-Behnken design was employed milligrams of Cysteine (X1), Trehalose (X2), and Tween 20 (X3) as independent variables. The dependent variables were quantified and the optimized formulation was prepared accordingly. SEC-HPLC and FTIR-spectroscopy were conducted to evaluate the molecular and structural status of spray-dried preparations. Particle characterization of optimized sample was performed with the aid of DSC, SEM, and TSI examinations.ResultsExperimental responses of a total of 17 formulations resulted in yield values, (Y1), ranging from 21.1 ± 0.2 to 40.2 ± 0.1 (%); beta-sheet content, (Y2), from 66.22 ± 0.19 to 73.78 ± 0.26 (%); amount of aggregation following process, (Y3), ranging from 0.11 ± 0.03 to 0.95 ± 0.03 (%); and amount of aggregation upon storage, (Y4), from 0.81 ± 0.01 to 3.13 ± 0.64 (%) as dependent variables. Results—except for those of the beta sheet content—were fitted to quadratic models describing the inherent relationship between main factors.ConclusionCo-application of Cysteine and Tween 20 preserved antibody molecules from molecular degradation and improved immediate and accelerated stability of spry-dried antibodies. Validation of the optimization study indicated high degree of prognostic ability of response surface methodology in preparation of stable spray-dried IgG.Graphical abstractGraphical abstractSpray drying of IgG in the presence of Trehalose, Cysteine and Tween 20.

The Anti-Inflammatory Effect of Spray-Dried Plasma Is Mediated by a Reduction in Mucosal Lymphocyte Activation and Infiltration in a Mouse Model of Intestinal Inflammation.

Spray-dried preparations from porcine and bovine plasma can alleviate mucosal inflammation in experimental models and improve symptoms in patients with enteropathy. In rodents, dietary supplementation with porcine spray-dried plasma (SDP) attenuates intestinal inflammation and improves the epithelial barrier function during intestinal inflammation induced by Staphylococcus aureus enterotoxin B (SEB). The aim of this study was to discern the molecular mechanisms involved in the anti-inflammatory effects of SDP. Male C57BL/6 mice were fed with 8% SDP or control diet (based on milk proteins) for two weeks, from weaning until day 33. On day 32, the mice were given a SEB dose (i.p., 25 µg/mouse) or vehicle. SEB administration increased cell recruitment to mesenteric lymph nodes and the percentage of activated Th lymphocytes and SDP prevented these effects). SDP supplementation increased the expression of interleukin 10 (IL-10) or transforming growth factor- β (TGF-β) compared to the SEB group. The SEB challenge increased six-fold the expression of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) and intercellular adhesion molecule 1 (ICAM-1); and these effects were attenuated by SDP supplementation. SEB also augmented NF-κB phosphorylation, an effect that was prevented by dietary SDP. Our results indicate that the anti-inflammatory effects of SDP involve the regulation of transcription factors and adhesion molecules that reduce intestinal cell infiltration and the degree of the inflammatory response.

Effect of the preparation method on crystallinity, particle size, aqueous solubility and dissolution of different samples of the poorly water-soluble fenofibrate with HP-β-CD

To determine the effect of the preparation method on the physicochemical properties, such as crystallinity, particle size, solubility and dissolution, of the poorly water-soluble fenofibrate, different samples were prepared from fenofibrate and hydroxypropyl-β-cyclodextrin (HP-β-CD) in a 1:1 molar ratio, by physical mixing, trituration, kneading, solvent-evaporation and spray-drying techniques. The corresponding aqueous solubilities and dissolutions were studied in comparison with that of the drug powder. Characterization of these samples was accomplished using particle size determination, powder x-ray diffraction, differential scanning calorimetry, thermogravimetry, scanning electron microscopy and Fourier transform infrared spectroscopy. All preparations improved the solubility and dissolution of the drug, as compared with that of the drug powder (P solvent-evaporation > kneading > trituration > physical mixing. In particular, the aqueous solubility of fenofibrate from the spray-dried preparation was 85.93 ± 6.82 µg/ml, and the dissolution was about 90 % within 20 min. The drug was present in the crystalline state in the physically mixed, triturated and kneaded preparations. However, it was converted into the amorphous state in the solvent-evaporated and spray-dried preparations. The spray-dried preparation having the smallest particle size of 2.44 ± 0.03 μm gave discrete particles. Thus, in the development of a preparation of the poorly water-soluble fenofibrate with HP-β-CD, the preparation method exhibits a significant effect on the physicochemical properties of the drug. Among the various preparations tested in this study, the spray-dried sample, which provided the highest solubility and dissolution of fenofibrate, is strongly recommended for possible administration via the oral route.

Hydrolysis of chicoric and caftaric acids with esterases and Lactobacillus johnsonii in Vitro and in a gastrointestinal model.

Chicoric acid (ChA) and caftaric acid (CafA) were identified as bioactive components of chicory and have been ascribed a number of health benefits. This study investigated the hydrolysis of ChA and CafA with enzymes and a probiotic bacterium Lactobacillus johnsonii (La1). Esterase from Aspergillus japonicus (24 U/mg) hydrolyzed 100% of ChA (5 mM) and CafA (5 mM) after 3 h, at pH 7.0 and 37 °C. Under the same reaction conditions, 100% hydrolysis of ChA and CafA was achieved with a spray-dried preparation of La1. The addition of La1 (100 mg/mL, 3.3 E9 cfu/g) to CafA solution in a gastrointestinal model (GI model) resulted in 65% hydrolysis of CafA. This model simulates the physicochemical conditions of the human gastrointestinal tract. No hydrolysis of CafA was observed after passage through the GI model in the absence of La1. The results of this study support the hypothesis that ChA and CafA are degraded by gut microflora before absorption and metabolization.

Physicochemical and antioxidant properties of spray dried preparations from Psidium guajava L

This work evaluated the antioxidant activity and physicochemical properties of spray dried preparations (SDP) from leaves of Psidium guajava L. Different drying carriers, namely: maltodextrin, colloidal silicon dioxide, Arabic gum and β-cyclodextrin at concentrations of 40 and 80% relative to solids content were added to drying composition. SDP were characterized through determination of the total phenolic, tannins and flavonoid content. Antioxidant activity of the SDP was assessed by two assays: cellular test that measure the luminol-enhanced chemiluminescence (LumCL) produced by neutrophils stimulated with phorbol myristate acetate (PMA) and the DPPH radical scavenging. SDP containing 40% of maltodextrin showed the best result with respect to total phenolics (18.09% w/w), tannins (10.21% w/w) and flavonoid contents (16.56% w/w). SDP were effective inhibitors of the PMA-stimulated neutrophil function [IC50 (in µg/106cells) ranging from 5.42 to 6.50 µg/mL. LumCL (IC50 of quercetin=1.67 µg/mL]. SDP showed antioxidant activities (IC50) ranging from 6.16 to 10.31 µg/mL by the DPPH method (IC50 of quercetin=0.96 µg/mL). The neutrophil reactive oxygen species generation, triggered by PMA and assessed by luminol was inhibited by SDP in a concentration-dependent manner, with insignificant toxicity to the cells under the tested conditions. Two chemical markers, catechin and quercetin which could be used in the monitoring of the quality of SDP were identified. Structural information of the compounds was obtained from the retention times, UV and mass spectra. In conclusion, SDP from Psidium guajava presented significant antioxidant activity with high potential as an active phytopharmaceutical ingredient for herbal medicine.

Fungitoxicity of lyophilized and spray-dried garlic extracts

Among the compounds discussed for anti-microbial and anti-fungal use allicin (allylthiosulfinate, diallyl disulfide-S-monoxide), an active ingredient of garlic, has attracted considerable attention. The objective of this study is to determine the antifungal activity of a local garlic ecotype (Voghiera) extracts against different pathogens. Primary screening was carried out by the agar plates technique using ethanol garlic extract at four final concentrations against the following organisms: Alternaria alternata, Aspergillus spp., Colletotrichum acutatum, Didymella bryoniae, Fusarium culmorum, Fusarium avenaceum, Fusarium gramineareum, Gliocladium roseum 47, Pythium splendens, Rhizoctonia solani, Sclerotium rolfsii, Stemphylium vesicarium, Trichoderma longibranchiatum, and Botrytis cinerea. Secondary screening was carried out using a lyophilized and a spray-dried preparation at different concentrations against the organisms selected for the high inhibition garlic effect in the primary screening and compared with the commercial fungicides mancozeb and iprodione. The best results were observed for the spray-dried garlic compound that showed a good fungicidal activity at the concentration of 1.5 g/10 mL while lyophilized garlic at the same concentration exhibithed less inhibition activity against the four fungi analyzed in the second screening.

Drying-Induced Variations in Physico-Chemical Properties of Amorphous Pharmaceuticals and Their Impact on Stability (I): Stability of a Monoclonal Antibody

The present study was conducted to investigate the impact of drying method and formulation on the storage stability of IgG1. Formulations of IgG1 with varying levels of sucrose with and without surfactant were dried by different methods, namely freeze drying, spray drying, and foam drying. Dried powders were characterized by thermal analysis, scanning electron microscopy, specific surface area (SSA) analysis, electron spectroscopy for chemical analysis (ESCA), solid state FTIR, and molecular mobility measurements by both isothermal calorimetry and incoherent elastic neutron scattering. Dried formulations were subjected to storage stability studies at 40 degrees C and 50 degrees C (aggregate levels were measured by size exclusion chromatography initially and at different time points). Both drying method and formulation had a significant impact on the properties of IgG1 powders, including storage stability. Among the drying methods, SSA was highest and perturbations in secondary structure were lowest with the spray-dried preparations. Sucrose-rich foams had the lowest SSA and the lowest protein surface accumulation. Also, sucrose-rich foams had the lowest molecular mobility (both fast dynamics and global motions). Stability studies showed a log-linear dependence of physical stability on composition. Preparations manufactured by "Foam Drying" were the most stable, regardless of the stabilizer level. In protein-rich formulations, freeze-dried powders showed the poorest storage stability and the stability differences were correlated to differences in secondary structure. In stabilizer-rich formulations, stability differences were best correlated to differences in molecular mobility (fast dynamics) and total protein surface accumulation.

Spray-drying preparation of microparticles containing cationic PLGA nanospheres as gene carriers for avoiding aggregation of nanospheres

Preparation of nano-sized particles using lyophilization, which is a standard drying technique for high-molecular-weight compounds such as bioactive peptides, proteins, plasmid DNA and siRNA, often results in particle aggregation. In this study, spray-drying was applied for preparation of cationic PLGA nanospheres as gene delivery vectors in order to minimize aggregation and loss of gene transfection efficiency. PLGA nanoparticle emulsions were prepared by dropping an acetone/methanol mixture (2/1) containing PLGA and a cationic material, such as PEI, DOTMA, DC-Chol or CTAB, into distilled water with constant stirring. The PLGA nanosphere emulsion was dried with mannitol by spray-drying, and mannitol microparticles containing PLGA nanospheres were obtained. Mean particle diameter of spray dried PLGA particles was 100–250 nm, which was similar to that of the nano-emulsion before drying, whereas the lyophilized PLGA particles showed increased particle diameter due to particle aggregation. PEI, DOTMA and DC-Chol were useful for maintaining nanoparticle size and conferring positive charge to nanospheres. Transfection of pDNA (pCMV-Luc) using these spray-dried cationic PLGA nanospheres yielded high luciferase activity in COS-7 cells, particularly with PLGA/PEI nanospheres. The present spray-drying technique is able to provide cationic PLGA nanospheres, and may improve redispersal and handling properties.

Particle design of indomethacin using a four-fluid-nozzle spray-drying technique

The spray-drying technique has previously been utilized as a method of improving the solubility of solid dispersion for poorly water-soluble drugs. This method disperses the drug in a molecular-state carrier, forming an amorphous, high-energy condition. In this study, we prepare matrix particles using hydroxypropylmethylcellulose (HPMC), which comprises indomethacin (IM) (a water-insoluble drug) and a carrier, using a four-fluid-nozzle spray-dryer. For comparison, we also evaluate the results gained with a conventional two-fluid-nozzle spray-dryer. Observation of the particle morphology by a scanning electron microscopy (SEM) reveals that the particles from the spray-drying technique atomize to several microns and that they become spherical. Assessment of the crystallinity of the spray-dried samples by powder X-ray diffraction and differential scanning calorimetry demonstrates that the IM becomes amorphized. These results indicate that the system forms a solid dispersion and that the particles become matrix particles. In the IM-HPMC system, the four-fluid-nozzle spray-dried preparation with a mixing ratio of 1:1 indicates remarkably improved dissolution rates in all pH solutions tested.

Particle Design Using a 4-Fluid-Nozzle Spray-Drying Technique for Sustained Release of Acetaminophen

We prepared matrix particles of acetaminophen (Act) with chitosan (Cht) as a carrier using a newly developed 4-fluid-nozzle spray dryer. Cht dissolves in acid solutions and forms a gel, but it does not dissolve in alkaline solutions. Therefore, we tested the preparation of controlled release matrix particles using the characteristics of this carrier. Act and Cht mixtures in prescribed ratios were dissolved in an acid solution. We evaluated the matrix particles by preparing a solid dispersion using a 4-fluid-nozzle spray dryer. Observation of the particle morphology by scanning electron microscopy (SEM) revealed that the particles from the spray drying process had atomized to several microns, and that they had become spherical. We investigated the physicochemical properties of the matrix particles by powder X-ray diffraction, differential scanning calorimetry, and dissolution rate analyses with a view to clarifying the effects of crystallinity on the dissolution rate. The powder X-ray diffraction peaks and the heat of the Act fusion in the spray-dried samples decreased with the increase of the carrier content, indicating that the drug was amorphous. These results indicate that the system formed a solid dispersion. Furthermore, we investigated the interaction between the drug and carrier using FT-IR analysis. The FT-IR spectroscopy for the Act solid dispersions suggested that the Act carboxyl group and the Cht amino group formed a hydrogen bond. In addition, the measurement results of the 13C CP/MAS solid-state NMR, indicated that a hydrogen bond had been formed between the Act carbonyl group and the Cht amino group. In the Act-Cht system, the 4-fluid-nozzle spray-dried preparation with a mixing ratio of 1 : 5 obtained a sustained release preparation in all pH test solutions.

Particle Design of Three-Component System for Sustained Release Using a 4-Fluid Nozzle Spray-Drying Technique

We prepared composite particles of acetaminophen (Act) with chitosan (Cht) and hydroxypropylmethylcellulose phthalate (HPMCP) as a carrier using a newly developed 4-fluid nozzle spray-dryer. Cht dissolves in acid solutions and forms a gel, but it is insoluble in alkaline solutions. On the other hand, HPMCP is insoluble in acid solutions, but it dissolves in alkaline solutions. Therefore, we tested a preparation of controlled release composite particles using the characteristics of these carriers. Act and Cht mixtures in prescribed ratios were dissolved in an acid solution. Composite particles of Act and HPMCP in prescribed ratios were dissolved in alkaline solutions. We evaluated the composite particles of the three components (Act, Cht, and HPMCP) by preparing solid dispersions using a 4-fluid nozzle spray-dryer. Observation of particle morphology by scanning electron microscopy (SEM) revealed that the particles from the spray-drying process had atomized to several microns and had all become spherical. We investigated the physical properties of the composite particles by powder X-ray diffraction, differential scanning calorimetry, and dissolution rate analysis to clarify the effects of crystallinity on the dissolution rate. Powder X-ray diffraction peaks and the heat of fusion of Act in the spray-dried samples decreased in proportion to the carrier content, indicating that the drug was amorphous. These results indicate that the Act-Cht-HPMCP system formed a solid dispersion. Furthermore, we investigated the interaction between the drug and the carrier using FT-IR analysis. FT-IR spectroscopy of the Act solid dispersions suggested that the Act carbonyl and Cht amino groups formed a hydrogen bond. On the other hand, interaction by hydrogen bond was observed between the carbonyl group of HPMCP with the amino group of Act. In the three-component Act-Cht-HPMCP system, the 4-fluid nozzle spray-dried preparation with a mixing ratio of 1 : 2.5 : 2.5 obtained sustained release preparation in all pH test solutions.

Influence of the drying method on the physical properties and immunomodulatory activity of the particulate (1→3)-β- d-glucan from Saccharomyces cerevisiae

The particulate (1→3)-β- d-glucan isolated from Saccharomyces cerevisiae cell walls was recovered from the aqueous medium as water-insoluble particles by different drying methods: solvent exchange (GE), lyophilisation (GL), and spray drying (GS). The samples were characterised by optical microscopy, FT-IR spectroscopy, swelling capacity, and rheological behaviour of aqueous dispersions. The immunological activity of the glucan samples was examined using the assay for the mitogenic and comitogenic activities. The drying method affected the microstructure of the glucan particles leading to differences in their physical properties (particle size and shape, swelling capacity, interparticle hydrogen bonding) as well as in the flow and viscoelastic properties. In comparison to GL and GE, the GS particles preserved the ellipsoid shape of yeast cells and exhibited a very low extent of interparticle hydrogen bonds. The rather liquid-like GS dispersion showed a several times lower apparent viscosity than the gel-like GE and GL dispersions. The results suggest that the physical state of the variously dried particulate glucan samples influenced significantly also their immunomodulatory activity which was found to be about twice higher with GS than with the GL and GE samples. The results indicated that for application of the particulate (1→3)-β- d-glucan as immunomodulator/adjuvans in form of aqueous suspension it is important to use spray-dried preparations.

Effects of Cellulose Derivatives and Additives in the Spray-Drying Preparation of Acetaminophen Delivery Systems

Microcrystalline cellulose (MCC), sodium carboxymethylcellulose (NaCMC), hydroxypropylmethylcellulose (HPMC), hydroxyethylcellulose (HEC), hydroxypro pylcellulose (HPC), and ethylcellulose (EC) were used for the production of time-controlled acetaminophen delivery systems using a spray-drying technique. The influence of factors such as polymer concentration, inlet temperature, and drug/polymer ratio were investigated. The product yields were a function of the type and concentration of the polymer, with the highest values being reached from feeds containing 1% MCC and EC. Parameters of 1% polymer concentration and an inlet temperature of 140°C gave rise to optimal processing conditions. Using these parameters, the influence of some adjuncts, such as polyethylene glycol 6000 (PEG 6000), dibutyl sebacate (DBS), polyvinylpyrrolidone (PVP), and carboxylic acids such as citric acid (CA), phthalic acid (PA), succinic acid (SA), tartaric acid (TA), and oxalic acid (OA), on the spray-drying process was evaluated. Of the additives tested, PVP (with MCC), DBS (with EC), and PEG 6000 (with NaCMC) induced yield decreases from 70% to 49%, 66% to 39%, and 37% to 17%, respectively. As for carboxylic acids (with NaCMC), similar or better performances of 43%, 45%, 47%, and 49% were obtained with SA, OA, PA, and TA, respectively. Dissolution studies in pH 1 dilute HCl and pH 6.8 phosphate buffer dissolution media showed that formulations consisting of 1% polymer with a drug/polymer ratio of 1/1 exhibited the slowest drug release, with the spheroids coated with NaCMC and HEC showing the longest T50% values (with 45 and 53 min at pH 1 and 49 and 55 min at pH 6.8, respectively). Slightly better sustained drug release in pH 6.8 dissolution medium was reached, showing the following trend: HEC > NaCMC > MCC > EC > HPMC. Concerning the additives, the trends in dissolution T50% of drug revealed TA > SA > CA > OA > PVP > PA > DBS in acidic pH 1 dissolution medium and PVP > OA > TA > SA > PA > CA > DBS in phosphate buffer at pH 6.8.

Quantitative determination of ?-endotoxin contents in spray-dried preparations ofBacillus thuringiensis strain GC-91

This report describes a method for quantifying δ-endotoxin contents in spray-dried preparations ofBacillus thuringiensis strain GC-91. δ-Endotoxin is solubilized in the pro-toxin form and separated from other soluble compounds by ion exchange chromatography. The method does not discriminate between the different δ-endotoxins produced by strain GC-91. It is suitable for quality control, since δ-endotoxin concentrations found in different preparations correlate inversely with the LC 50 in bioassays on artificial diet against freshly hatched larvae ofSpodoptera littoralis. A typical batch of spray-dried material contains 1.22%±0.08% δ-endotoxin. The method is most accurate with preparations containing 0.5 to 2.0% toxin, for which triplicate estimations give standard errors close to±0.2%.

Nutritional value of spray-dried Tetraselmis suecica for juvenile bivalves

Juvenile bivalves of five commercially important species ( Tapes philippinarum, T. decussata, Mercenaria mercenaria, Crassostrea gigas and Ostrea edulis) were fed a spray-dried preparation of Tetraselmis suecica. Growth and carbohydrate content of the juveniles were measured and compared with animals fed live T. suecica, a live diatom ( Chaetoceros calcitrans), or a mixture of these two algae. Dry weight growth rate and carbohydrate content were similar for juveniles fed dried or live T. suecica. Growth rate was less and carbohydrate content greater than those for animals fed C. calcitrans or the mixed live diet. Food cell consumption rates of the various diets were compared. In most cases, the weight of each diet eaten was similar for each bivalve species. Preliminary observations on the effect of supplementing the dried diet with live algae show that a mixture containing 20% C. calcitrans gave improved growth.

Pigmentation of Cultured Striped Jack Reared on Diets Supplemented with the Blue-Green Alga Spirulina maxima.

Pigmentation of cultured striped jack Caranx delicatissimus was attempted by feeding diets supplemented with a commercial spray-dried preparation of the blue-green alga Spirulina maxima which is abundant in zeaxanthin. The integumentary color of the fish reared on diets containing the alga at 5% or 10% became irridescent greenish gray at the back with a characteristic yellow band near the lateral line, whereas those reared on the control diet or frozen sardine exhibited dark gray. Analysis of the integuments revealed that contents of carotenoids were 0.28-1.50mg/100g at the dorsal part and 0.14-0.48mg/100g at the ventral one, being higher in the fish reared on the diets containing the alga. More than 95% of the carotenoids in the dorsal integuments were com-posed of three yellow ones, tunaxanthin, lutein, and zeaxanthin, and all of them increased by sup-plementation of S. maxima.