Biological Activities of Freshwater Algae,Spirogyra singularis Nordstedt

Spirogyra is commonly found as accessible algae in freshwater areas all over the world. Some medical uses have been reported from this genus. Biological activities of Spirogyra singularis were investigated employing eight in vitro assays. The extract showed different antioxidant activity. IC₅₀ for DPPH radical-scavenging was 4.71 ± 0.11 μg mL^?1. The extract showed very strong nitric oxide-scavenging activity with IC₅₀ = 77.3 ± 2.07 μg mL^?1, but its Fe²⁺ chelating ability was weak. The extract also exhibited high antioxidant activity in hemoglobin-induced linoleic acid peroxidation tests and scavenging of hydrogen peroxide. The extract also showed good antihemolytic activity. The total amount of phenolic content in the extract was determined as gallic acid equivalents, and total flavonoid content was calculated as quercetin equivalents. Biological activities may be attributed, at least in part, to the presence of phenol and flavonoid contents in the extract.     

Antioxidant and anti‐inflammatory activities of Pinus radiata bark extract in salmonid cell lines

A fish meal supply shortage is limiting aquaculture development. Currently, plant‐based proteins, such as soya bean meal, are being used as an alternative protein source, despite that such a diet can adversely affect fish, such as by inducing an inflammatory response. A possible solution is to include dietary additives in farm diets to counteract negative effects. One such solution originates from pine bark extracts, which present bioactive properties. In this study, the antioxidant and anti‐inflammatory properties of Pinus radiata bark extracts were evaluated for the first time in a salmonid cell line. This extract chemically demonstrated antioxidant activity through 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH = 58.4 ± 1.1%) and ferric ion reducing antioxidant power (FRAP = 575 ± 17 mgEqFe(II)·g extract^?1) assays. Additionally, the extract showed high flavonoid and phenolic compound contents. Up to 100 mg mL^?1, the P. radiata extract showed no cytotoxicity in the CHSE‐214 salmonid embryo cell line. Moreover, the antioxidant activity of the extract (50 μg mL^?1) was evaluated by a dichlorofluorescein (DCFH) assay in the SHK‐1 salmon cell line challenged with an oxidant stimulus (H₂O₂), showing 58.9% activity. The extract also protected DNA from oxidative damage, as observed through a comet assay. When assessing anti‐inflammatory properties in an in vitro inflammation model, the extract significantly reduced the relative expression of the pro‐inflammatory cytokines interleukin‐1β (IL‐1β), tumour necrosis factor‐α (TNF‐α) and interleukin‐8 (IL‐8) and of the inducible cyclooxygenase‐2 (COX‐2) enzyme. These results suggest a potential application of P. radiata bark extract in functional foods in aquaculture.     

Functional Properties of the Marine Gastropod Molluscs Chicoreus ramosus and Babylonia spirata Collected from the Southern Coast of India

ABSTRACT

This study characterized the functional properties of ethyl acetate-methanol (EA-MeOH) and chloroform extracts of the muricid gastropod Chicoreus ramosus and buccinid Babylonia spirata. The EA-MeOH extract of B. spirata was a potent quencher of radical cation (IC₉₀ < 1 mg/mL), whereas that of C. ramosus held greater anti–inflammatory potential (IC₉₀ 5-lipoxygenase inhibition 1.74 mg/mL) than the buccinid gastropod. The EA-MeOH extract of C. ramosus displayed potent antidiabetic activities as deduced by its attenuation properties against carbolytic enzymes α-amylase and α-glycosidase (IC₉₀ 1.06 and 2.25 mg/mL, respectively) than those exhibited by B. spirata (IC₉₀ 2.32 and 4.50 mg/mL, respectively). The spectroscopic dereplication studies to determine probable chemical groups in the solvent extracts of the studied gastropods revealed the presence of functionalities, which might augment the electronic properties of the bioactive principles present within the extract, thereby enhancing their activity. Thus, the present study recognized that marine gastropods C. ramosus and B. spirata have potential functional implications against oxidative stress-induced diseases, such as diabetes and inflammation. This research supports further investigation of these previously uncharacterized marine gastropod species to isolate potential bioactive leads for use against various biological targets and to develop functional food formulations.     

Pharmacokinetics and tissue residues of marbofloxacin in crucian carp (Carassius auratus) after oral administration

Pharmacokinetics and residue elimination of marbofloxacin (MBF) were studied in crucian carp (Carassius auratus, 250±30 g) kept at two water temperatures of 15 and 25 °C. Marbofloxacin concentrations in plasma and tissues were analysed by means of high‐performance liquid chromatography using an ultraviolet detector. The limits of detection were 0.02 μg mL^?1, 0.02 μg g^?1, 0.025 μg g^?1, 0.02 μg g^?1 and 0.025 μg g^?1 in plasma and muscle, skin, liver and kidney respectively. Fish were administered orally at a single dosage of 10 mg kg^?1 body weight in the PK group. The data were fitted to two‐compartment open models at both temperatures. At 15 °C, the absorption half‐life () and distribution half‐life (t_1/2α) of the drug were 0.36 and 4.48 h respectively. The corresponding values at 25 °C were 0.23 and 0.87 h respectively. The elimination half‐life (t_1/2β) was 50.75 h at 15 °C and 25.05 h at 25 °C. The maximum MBF concentration (C_max) differed little between 15 (6.43 μg mL^?1) and 25 °C (8.36 μg mL^?1). The time to peak concentration was 1.74 h at 15 °C and 0.78 h at 25 °C. The apparent volume of distribution (V_d/F) of MBF was estimated to be 1.36 and 0.87 L kg^?1 at 15 and 25 °C respectively. The area under the concentration–time curve (AUC) was 301.80 μg mL^?1 h at 15 °C and 182.80 μg mL^?1 h at 25 °C. The total clearance of MBF was computed as 0.03 and 0.05 L h^?1 kg^?1 at 15 and 25 °C respectively. After repeated oral administration at a dosage of 10 mg kg^?1 body weight per day for 3 days, the results showed that the elimination half‐lives () of MBF from all tissues at 15 °C were longer than that at 25 °C. Therefore, water temperature is an important factor to be considered when deciding a reasonable withdrawal time.     

Sea cucumber Holothuria forskali,a new resource for aquaculture? Reproductive biology and nutraceutical approach

Sea cucumbers are highly marketable as a food product due to their nutritional value. Also, it has been suggested that sea cucumbers possess a wide range of bioactive compounds that can be used in the pharmaceutical industry. In this study, the reproductive biology of Holothuria forskali was performed by evaluating the gonadosomatic index (GI) and histological analyses of the gonadal tubules. The biotechnological potential was assessed through the evaluation of the antioxidant, antimicrobial and antitumor potential. Finally, the fatty acid profile was also evaluated. These three subjects were chosen to increase the interest and to focus the economic potential of this species rearing, predicting that it can be sold in Europe or export to Asia to be used for human consumption or for the pharmaceutical industry. The GI and the histological analysis of the gonadal tubules revealed that the range from February to March corresponds to the peak of gonads maturation. Furthermore, the methanolic fraction revealed the highest antimicrobial potential against Candida albicans with an IC₅₀ of 233.2 mg mL^?1. Also, this fraction presented the highest cytotoxic and anti‐proliferative activities through the method for measuring cell proliferation method in both cell lines, with an IC₅₀ of 238.2 and 396.0 mg mL^?1 for MCF‐7 cells respectively and 260.3 and 218.7 mg mL^?1 for HepG‐2 cells respectively. Regarding the fatty acid profile, the total fat content was 4.83% and the highest values were obtained for palmitic acid (9.96%), stearic acid (11.23%), eicosapentaenoic acid (10.49%) and arachidonic acid (20.36%).     

Effect of esterification on the absorption of astaxanthin in rainbow trout, Oncorhynchus mykiss (Walbaum)

Gastrointestinal and serum absorption of astaxanthin was studied in rainbow trout, Oncorhynchus mykiss (Walbaum) (217 ± 2 g) fed diets supplemented with either esterified astaxanthin (from Haematococcus pluvialis) or free astaxanthin (synthetic, as 8% w/w beadlets) at similar levels (50 mg kg^?1). After 56 days of feeding, there was a significant difference (P = 0.0582) between steady‐state serum astaxanthin concentrations for fish fed free (2.0 ± 0.3 μg mL^?1) or esterified astaxanthin (1.3 ± 0.1 μg mL^?1) at the 90% confidence level. However, following ingestion of a single meal supplemented with free or esterified astaxanthin, the rates of astaxanthin absorption into serum were not significantly different (P > 0.1) (0.8 ± 0.2 µg mL^?1 h^?1 and 1.0 ± 0.4 µg mL^?1 h^?1 respectively). In fish fed both free or esterified astaxanthin, higher absorption (P < 0.05) of astaxanthin by the ileal (0.8 ± 0.14 μg g^?1 and 0.9 ± 0.15 μg g^?1 respectively) compared with the posterior (0.2 ± 0.01 μg g^?1 and 0.3 ± 0.14 μg g^?1 respectively) intestine was recorded. This confirmed the role of the anterior intestine in carotenoid absorption. Non‐detectable levels of esters in digesta taken from the hind intestine suggest the anterior intestine is also the primary region for ester hydrolysis.     

Angiotensin Converting Enzyme and Dipeptidyl Peptidase-IV Inhibitory,and Antioxidant Activities of a Blue Mussel (Mytilus edulis) Meat Protein Extract and Its Hydrolysates

ABSTRACT

Protein extracted from mussel processing coproducts was hydrolyzed with four different food-grade enzyme preparations and assessed for angiotensin converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibitory and oxygen radical antioxidant capacity (ORAC) activities. All hydrolysates tested showed higher activity than the intact protein. ACE and DPP-IV IC₅₀ values in the range 1.13–3.34 and 0.33–2.43 mg mL^?1, respectively, and ORAC values in the range 66.26–121.56 µmol trolox equivalents g^–1 were obtained. These results suggest that some of the mussel meat protein hydrolysates may have potential as functional food ingredients for the management of diseases such as type II diabetes and hypertension.     

Optimization of blue mussel (Mytilus edulis) seed culture using recirculation aquaculture systems

By introducing recirculation aquaculture systems (RAS) in the nursery phase of the blue mussel (Mytilus edulis) (17–18 mm), we aimed at a similar growth and survival and a similar water quality compared to the commonly used flow‐through systems (FTS). To calculate water flow and size of the biofilter, a series of experiments were done to determine clearance rate (9.26 mL min^?1), pseudo faeces threshold (60 000 cells Pavlova lutheri mL^?1), nitrogen production (0.00065 mg TAN h^?1 ind^?1 and 1.6 × 10^?5 mg NO₂–N h^?1 ind^?1) and oxygen consumption (0.03 ± 0.01 mg O₂ h^?1 ind^?1). RAS showed no significant differences in water quality (0.06 mg TAN L^?1; 7.7 mg O₂ L^?1) and growth performance of mussel seed specific growth rate (SGR = 5% day^?1) after the experimental period of 4 weeks compared with FTS. The low water refreshment, 10% per day, as well as the constant chlorophyll concentrations (9.76 ± 1.06 μg L^?1), suggests the potential of RAS as culture system for mussel seed.     

Effects of supplementing bioactive compounds to a formulated diet on sensory compounds and growth of shrimp,Litopenaeus vannamei (Boone, 1931)

Experimental diets were processed at the Oceanic Institute by adding various bioactive compounds (lutein, fucoxanthin, astaxanthins (Ax), glucosamine, carotenoid mix, phytosterol mix, bromophenol (Bp) mix or their combination) to a formulated (control) diet to examine their effects on sensory composition and growth of shrimp. These diets and a commercial feed were fed to ～1.6 g shrimp (Litopenaeus vannamei) in four replicates in an indoor laboratory under flow‐through conditions for 8 weeks. Results indicated that all the supplementations of the bioactive compounds did not improve shrimp growth (0.79–0.97 g week^?1) compared with that (0.94 g week^?1) of the control diet (P>0.05). However, inclusion of lutein (200 mg kg^?1) or carotenoid mix (827 mg kg^?1) in the control diet (with supplemental Ax) resulted in much higher free Ax (48.3 or 46.5 mg kg^?1) and esterified Ax (6.2 or 3.9 mg kg^?1) content in shrimp tails than the control diet (28.4; 1.4 mg kg^?1 respectively) (P<0.05). Inclusion of Bp (2 mg kg^?1) in the control diet resulted in higher levels of Bp (160 μg kg^?1) in shrimp tail muscle than the control diet (81 μg kg^?1) (P<0.05). Three free amino acids, glycine, proline and alanine might be mainly responsible for the sweet taste of L. vannamei. The results suggest that the supplementation of the bioactive compounds may not affect shrimp growth performance, but some may affect the composition and taste of shrimp.     

Replacement of live food with a microbound diet in feeding Litopenaeus setiferus (Burkenroad) larvae

Microbound feeds have been well accepted by shrimps and farmers in many penaeid shrimp hatcheries. The present study focused on an adequate level of replacement of Artemia nauplii and microalgae by a microbound diet for rearing Litopenaeus setiferus (Burkenroad) larvae. A microbound diet (MBD) consisting of fishmeal, squid meal, shrimp meal, yeast meal and soybean meal was used. The first experiment was designed to obtain the optimum level of MBD to complete the live feeding schedule, from Protozoea (PZ_III) to Mysis (M_III). The experimental levels of the microbound diet tested were 2, 4, 6 and 8 mg MBD L^?1 day^?1. The next step was to determine the Artemia nauplii replacement level from PZ_I to M_III by MBD. These experiments were carried out either in the presence (Experiment 2) or in the absence of algae (Experiment 3). Four replacement levels were tested: 0% (4 mg MBD L^?1 day^?1: 1 Artemia nauplii mL^?1), 40% (5.5 mg MBD L^?1 day^?1: 0.6 Artemia nauplii), 60% (6.5 mg MBD L^?1 day^?1: 0.4 Artemia nauplii) and 100% (8 mg MBD L^?1 day^?1: 0 Artemia nauplii). In all experiments growth, survival, development, quality index (QI) and performance index (PI), were used to determine the optimum concentration of microbound diet. Results showed that 6 mg MBD L^?1 day^?1 can be recommended as a complement to live food for L. setiferus larvae from PZ_III to M_III. In the presence of algae, maximum growth and survival may be obtained in 40–60% (5.5–6.5 mg MBD L^?1 day^?1) of Artemia nauplii replacement levels. In the absence of algae, the Artemia nauplii replacement resulted in slower development, less salinity resistance, lower growth and lower survival than was obtained in larvae fed with algae.     

Bioencapsulation of five forms of erythromycin by adult Artemia salina (L.)

Uptake of five chemical forms of erythromycin by adult Artemia salina (L.) (erythromycin phosphate – EP, erythromycin stearate – ES, erythromycin estolate – EE, erythromycin hydrate – EH and crystalline erythromycin – CE) was investigated in two trials. In each trial, final erythromycin concentration in Artemia tissue and survival after a 12‐h bioencapsulation period were determined. In the first trial, Artemia tissue concentration after a 12‐h bioencapsulation period was significantly (P < 0.05) affected by erythromycin form with ES (68.5 ± 3.3 μg mL^?1, mean ± SEM) ≈ EH (61.2 ± 3.4 μg mL^?1) > CE (37.1 ± 10.7 μg mL^?1) > EP (16.4 ± 7.7 μg mL^?1) > control. In trial 2, Artemia tissue concentration was also significantly (P < 0.05) affected by erythromycin form with EE (111.4 ± 9.6 μg mL^?1) > CE (89.1 ± 1.7 μg mL^?1) > ES (78.9 ± 1.6 μg mL^?1) > EP (33.4 ± 5.2 μg mL^?1) > control. Survival was significantly affected by erythromycin form in trial 1 with EP=control (100 ± 0.0%) > ES (74.4 ± 2.0%) > CE (32.2 ± 0.3%) > EH (8.8 ± 4.4%). In trial 2, survival was also significantly affected by erythromycin form with EP=control (100 ± 0.0%) > ES (67.1 ±3.7%) > CE (52.5 ± 7.7%) > EE (5.0 ± 2.5%). Based on both uptake and survival, EP and ES appear to be appropriate compounds for bioencapsulation of erythromycin using live adult Artemia.     

Dietary supplementation with the microalgae Parietochloris incisa increases survival and stress resistance in guppy (Poecilia reticulata) fry

Dietary enrichments with the arachidonic acid (ARA)‐rich microalga, Parietochloris incisa, on the survival of guppy (Poecilia reticulata) fry were examined. Diets were applied via Artemia enrichment to fish from two commercial farms for 34 and 36 days of experimental period (trials 1 and 2, respectively). In trial 1, Artemia nauplii were enriched with dry biomass of whole algal cells at 0 (control), 0.1, 0.2 and 0.4 mg mL^?1. Fry fed with Artemia enriched with 0.4 mg mL^?1 demonstrated the lowest mortality rates (24% and 1% in farms 1 and 2, respectively) compared with controls (36% and 13% in farms 1 and 2, respectively). In trial 2, fry were fed with Artemia, enriched with whole algal cells (0.4 mg ml^?1), algal hexane extract (HE; containing primarily ARA‐rich triacylglycerols and β‐carotene; 0.19 mg ml^?1) or the extraction residue (0.28 mg ml^?1). Acute stress (5 min air exposure) was applied after 18 days. The lowest mortality was recorded in the whole alga‐fed group (av. 26% and 2.6% in farms 1 and 2, respectively), with a slightly, but not significantly higher mortality in the HE‐fed group (av. 29% and 6.2% in farms 1 and 2, respectively). Elevated lysozyme was associated with the reduced mortality. Overall, the use of P. incisa as a dietary supplement for guppy fry during their first month of life enhanced their survival and stress resistance.     

Anti-Inflammatory Concentrate Enriched with Substituted Oligofucans Derived from Brown Seaweed Turbinaria conoides (J. Agardh) Kützing and Its Safety Assessment on Wistar Rats

ABSTRACT

Aqueous extract of the seaweed Turbinaria conoides was purified to obtain an oligofucan-enriched seaweed concentrate (OESC). Oligofucans isolated were characterized as two types with (→1)-fucose-(2,3-diSO₃^?)-(1→4)-fucose-(2-SO₃^?)-(1→3)-fucose-(2,3-diSO₃^?)-(1→4)-fucose-(2-SO₃^?, 3-OAc)-(4→) and (→1)-fucose-(3-SO₃^?)-(1→4)-fucose-(2-SO₃^?)-(1→4)-fucose-(3-SO₃^?)-(1→4)-fucose-(2-SO₃^?)-(4→) motifs. A 90-day accelerated shelf-life study (50°C) showed that OESC maintained its antioxidant properties (free radical scavenging, reducing, lipid peroxidation inhibition, and chelating activities) even after 30 days. In vitro COX-2 and 5-LOX inhibitory properties of OESC (67.2 and 95.2%, respectively) showed no significant variation even at the 30th day. OESC significantly mitigated the carrageenan-induced inflammation in rats at 0–2 h (59.7–70.3% inhibition), which were greater compared to the synthetic NSAID aspirin. The safety of OESC has been assessed by acute (14 days) and subchronic (90 days) oral toxicity studies, which showed no toxicity-related significant changes in renal or hepatic function, hematological indices, and serum biochemical parameters in the OESC-treated Wistar rats. No histopathological alterations were observed in the vital organs of rats treated with OESC. LD₅₀ and sub-chronic no-observed-adverse-effect level (NOAEL) for this concentrate were found to be > 5,000 and 2,000?mg/kg BW, respectively. Hence, oligofucan-enriched seaweed concentrate is safe to consume without any adverse effects in the body.     

Dynamics of glucose in the haemolymph of female giant freshwater prawn,Macrobrachium rosenbergii,influences reproductive and non‐reproductive moulting cycles

Glucose, when measured in haemolymph, has been found to reflect a useful predictor of energetic investment. This study evaluated the pattern of glucose in the haemolymph, with an attempt to gain a better insight into the role of glucose as nutritional source of ovarian development and energy reserves during reproductive and non‐reproductive moulting cycles. The haemolymph of female giant freshwater prawn, Macrobrachium rosenbergii, was obtained at eight different moulting stages, and levels of glucose were determined using an enzymatic colorimetric glucose‐oxidase method in parallel with a histological examination of ovarian development. Glucose levels were relatively low (0.15 ± 0.02 mg mL^?1) at D₀ stage, an abrupt increase (0.52 ± 0.13 mg mL^?1) during premoult D₁ stage and declined (0.32 ± 0.10 and 0.31 ± 0.09 mg mL^?1) during premoult D₂ and D₃ stages, respectively; thereafter, a slight increase (0.43 ± 0.09 mg mL^?1) occurred at post‐moult A stage. The progression of ovarian growth, marked by an increasing gonadosomatic index (GSI) pattern during the reproductive moulting cycle (C₀–D₃ stages), was directly proportionate to fluctuations in glucose levels. GSI was significantly positively correlated with glucose (R = 0.40; P < 0.05). In contrast, glucose was notably higher at post‐moult A and premoult D₂ stages during non‐reproductive moulting cycle, the period during which glucose is crucial for exoskeletal chitin synthesis. At this particular stage, a negative correlation between body weight and glucose (R = ?0.36; P < 0.05) was observed. The dynamics of glucose in the haemolymph of female M. rosenbergii correlated with ovarian growth, which signify that glucose as nutritional source for vitellogenesis, and affects the body weight of this species.     

The kinetic profile of oxolinic acid in sharpsnout sea bream, Diplodus puntazzo (Cetti 1777)

The pharmacokinetics of oxolinic acid (OA) were investigated after a single intra‐vascular injection (20 mg kg^?1 fish) in sharpsnout sea bream (90 g), a promising new euryhaline species for Mediterranean fish farming. The distribution half‐life (t_1/2α) and the elimination half‐life (t_1/2β) of OA were calculated to be 0.4 and 10 h respectively. The apparent volume of distribution at steady‐state (V_d(ss)) and total clearance rate (CL_T) of the drug were found to be 2.1 L kg and 0.2 L kg^?1 h^?1 respectively. The bioavailability (F%) of OA following oral administration (40 mg kg^?1 fish) was estimated to be 15%. The results indicate a rapid distribution and elimination of the drug, moderate tissue penetration, but low absorption in sharpsnout sea bream. The kinetic profile of OA found in this species is comparable with that observed in another well‐known sparid, gilthead sea bream.     

In vitro effect of the red alga Hydropuntia cornea (J. Agardh) on the respiratory burst activity of sole (Solea senegalensis, Kaup 1858) phagocytes

The stimulatory effect of different extracts from the red alga Hydropuntia cornea (formerly Gracilaria cornea) on the respiratory burst activity of sole phagocytes was evaluated in vitro. Aqueous and ethanolic extracts and extracellular polysaccharidic fractions from algal cultures were assayed. Phagocytes, isolated from sole kidney, were incubated in vitro with different algal fractions at concentrations of 10, 5, 2 and 1 mg mL⁻¹. As a positive control, commercial β‐glucan from the alga Euglena gracilis was used. The results obtained indicate that an ethanolic extract from H. cornea, at 10 mg mL⁻¹, is capable of enhancing superoxide anion production in sole phagocytes when the cells are incubated for 30 min with the bacterium P. damselae ssp. piscicida and the extract. On the other hand, the commercial β‐glucan leads to a significant increase at highest concentration, 10 mg mL⁻¹, after 30 min of incubation.     

Differential pathogenicity of five Streptococcus agalactiae isolates of diverse geographic origin in Nile tilapia (Oreochromis niloticus L.)

Streptococcus agalactiae is an emerging pathogen of fish and has caused significant morbidity and mortality worldwide. The main objective of this study is to assess whether pathogenic differences exist among isolates from different geographic locations. Nile tilapia (Oreochromis niloticus L.) were administered an intraperitoneal injection of suspension containing USA, Brazil, Honduras, Israel, or Kuwait S. agalactiae isolates at concentrations ranging from 10² to 10⁷ cfu mL^?1. The LD₅₀ values 7 days after challenge were as follows: USA (1.0 × 10² cfu mL^?1), Brazil (1.5 × 10³ cfu mL^?1), Honduras (6.8 × 10³ cfu mL^?1), Israel (1.0 × 10⁴ cfu mL^?1) and Kuwait (7.2 × 10⁵ cfu mL^?1). Fish from all groups exhibited lethargy, anorexia, exophthalmia, corneal opacity, erratic swimming, petechiae and mortality. Opercular clearing and ascites were only found after infection with certain geographic isolates. The findings in this study indicate that S. agalactiae isolates of different geographic origin can cause significant mortalities after experimental challenge and can have different pathogenic capacities. Isolates from the Americas (USA, Brazil and Honduras) were more pathogenic to Nile tilapia than isolates from the Middle East/Asia (Israel and Kuwait).     

A3α‐peptidoglycan extracted from Bifidobacterium sp. could enhance immunological ability of Apostichopus japonicus

To assess the effects of A3α‐peptidoglycan (A3α‐PG) extracted from Bifidobacterium sp. on the immune response and disease resistance of sea cucumber, different concentrations (0, 0.5, 5 and 50 mg mL^?1) of A3α‐PG suspensions were used to perform hypodermic injection on Apostichopus japonicus, followed by a Vibrio splendidus challenge. Total coelomocyte count (TCC), phagocytosis activity and activities of four immunological enzymes in both cell‐free coelomic fluid (extra‐cellular, EC) and coelomocyte lysate supernatant (intracellular, IC), including acid phosphatase (ACP), alkaline phosphatase (ALP), superoxide dismutase (SOD) and peroxidase (POD), were measured at 2, 6, 14 and 24 h post injection (hpi). The TCC was not significantly affected (P > 0.05) by A3α‐PG, ranging from 1.84 × 10⁶ to 3.53 × 10⁶ cells mL^?1. The coelomocyte phagocytosis activity was significantly activated (P < 0.05) in all the A3α‐PG treatments, whereas no significant difference was observed between them except 24 hpi (P > 0.05). The EC‐ACP activity in the 5.0 mg mL^?1 treatment increased significantly (P < 0.05) at all sampling times, while the IC‐ACP activity in the 50 mg mL^?1 treatment increased significantly (P < 0.05) at 2 hpi. Also, the 5.0 mg mL^?1 treatment had significant (P < 0.05) increase in the EC‐ALP activity within 14 hpi and the EC‐POD activity at 2 hpi, respectively, while significantly (P < 0.05) enhanced IC‐ALP and IC‐POD activities were observed in the 50 mg mL^?1 treatment within 6 hpi and at 2 hpi, respectively. Only the 5.0 mg mL^?1 treatment showed significant (P < 0.05) increase in the EC‐SOD activity at 2 hpi and IC‐SOD activity within 14 hpi, respectively. The challenge test showed that the animals treated with 50 mg mL^?1 of A3α‐PG had notably lower cumulative mortality after 14 days following V. splendidus exposure. All together, these results suggest that A3α‐PG could positively enhance immune response that effectively promotes the health status of A. japonicus against V. splendidus infection.     

The degree of carotenoid esterification influences the absorption of astaxanthin in rainbow trout, Oncorhynchus mykiss (Walbaum)

The absorption of astaxanthin from diets (30 mg kg^?1 inclusion) supplemented with either unesterified astaxanthin; isolated astaxanthin monoesters, diesters or a cell‐free carotenoid extract from Haematococcus pluvialis were studied in rainbow trout (>200 g). No significant differences (P > 0.05) were recorded in the apparent digestibility coefficients (ADC) (≈60–65%) between astaxanthin sources. However, following consumption of a single meal, peak serum astaxanthin levels at 32 h (≈1.0–1.6 μg mL^?1) were significantly higher (P < 0.05) in fish fed unesterified astaxanthin and astaxanthin monoester, compared to fish fed astaxanthin diester and the cell free extract. However, no significant differences (P > 0.05) were recorded in serum astaxanthin uptake rates between sources of astaxanthin. Results suggest that the extent of carotenoid esterification negatively influences the peak serum levels of astaxanthin in rainbow trout.     

Inhibitory activity of essential oils from medicinal plants against Pseudomonas sp. isolated from aquatic environments

This study focuses on the evaluation of the antimicrobial activity of essential oils (EOs) from medicinal plants against Pseudomonas sp isolated from aquatic environments, and proves its controlling efficacy on Pseudomonas aeruginosa‐Dahp1 using Confocal Laser scanning Microscopy. Twenty‐seven Pseudomonas spp. (Ps ₁–Ps ₂₇) were isolated using King's B medium and the selected P. aeruginosa‐Dahp1 was confirmed using 16S r‐DNA methods. Antimicrobial activity of 10 EOs was determined using agar well and disc diffusion methods. Ten EOs were extracted with six solvents and the crude extracts were tested against the Pseudomonas spp. through disc diffusion method. Among 10 EOs tested, maximum inhibitory activity was noted in EOs of Wringtia tinctoria against the P. aeruginosa‐Dahp1 in the disc diffusion method. The MIC values (concentrations were expressed in Weight/Volume) of the EOs range from 0.5 to 9.054 mg mL^?1. The EO of W. tinctoria showed the maximum activity at the concentration (w/v) of 2.060 mg mL^?1. The EO of W. tinctoria with chloroform extract showed the maximum inhibition against P. aeruginosa‐Dahp1. The CLSM proves the control and viability of 1 × 10⁵ CFU mL^?1 of P. aeruginosa‐Dahp1 at a lower concentration (2.720 mg) of EOs with chloroform extracts of W. tinctoria. This study pivots for designing of new drugs using EOs of W. tinctoria against Pseudomonades in the aquaculture sites.