Serum Phenoloxidase Activity Research Articles

Effects of replacing soybean meal with fermented rapeseed meal in low-fish-meal feed on the growth, immunity, and gut microbiota of juvenile white shrimp, Litopenaeus vannamei

This experiment was conducted over a period of 8 weeks to investigate the effects of replacing soybean meal with fermented rapeseed meal (RM) on the juvenile white shrimp Litopenaeus vannamei. Six diets were prepared on an isonitrogenous and isolipidic basis. The normal fish meal (FM) group was used as a positive control, and the high soybean meal (SM) group was used as a negative control. The experimental groups used RM to replace 25 % (RM25), 50 % (RM50), 75 % (RM75) and 100 % (RM100) of the soybean meal in the low-fish-meal diet. All six diets were set up with four replicate groups stocking 25 shrimp (1.04 ± 0.04 g, N = 24) in each replicate tank. The results showed that weight gain was negatively correlated with RM addition. Compared with that in the FM group, the malondialdehyde content in the hepatopancreas was significantly lower in the RM25, RM50 and RM100 groups. Superoxide dismutase activity was positively correlated with the amount of substitution. The catalase activity and bacteriolytic activity were significantly lower in the RM50, RM75 and RM100 groups than in the SM group. The serum phenoloxidase activity in the RM50 group was not significantly different from that in the FM group. Based on the transcriptome data, the high RM level diet had a significant effect on lipid metabolism pathways in the hepatopancreas and resulted in the downregulation of transcripts related to “oxidoreductase activity”. Increased RM levels lead to separation of the intestinal mucosa from the base. High concentrations of RM can also increase the relative abundance of pathogenic bacteria (Nautella, Acinetobacter). The relative abundance of Proteobacteria in the RM100 group was also the highest of several groups. In summary, RM can replace 25 % of soybean meal in low-fish-meal feeds without affecting the growth performance of L. vannamei. Higher levels of fermented rapeseed meal in the feed (>50 %) can suppress the immunity of shrimp, affect lipid metabolism and cause intestinal flora imbalance.

Detection and substrate portrayal on the serum phenoloxidase activity from the grub of rhinoceros beetle, Oryctes rhinoceros.

Phenoloxidase (PO) is a significant biomolecule involved in humoral defence mechanism of invertebrates. Spontaneous melanization of insect haemolymph is the major hinderance for studying PO activity, as haemolymph was collected devoid of phenylthiourea. In the study, no visible melanization was observed in crude serum from the grub of Oryctes rhinoceros up to 30 min of incubation amongst crude haemolymph, diluted haemolymph, crude serum and diluted serum that were subjected to visual observation for spontaneous melanization reaction. Accordingly, crude serum was taken for evaluating PO activity. At the same time, as PO substrates tend to auto-oxidize and provide false optical density value, tris-buffered saline devoid of any substrates were used as blank for PO assays. The ideal wavelength at which maximum PO activity occurred for each substrate, namely, tyrosine, tyramine, dopamine, L-dopa, DL-dopa, catechol, protocatechuic acid and pyrogallol was determined as 407, 410, 429, 465, 403, 466, 428 and 400 nm, respectively. Additionally, time course of oxidation for each phenolic substrate by the serum PO were examined and DL-dopa was identified as the specific substrate for serum PO in the grub of O. rhinoceros. Furthermore, maximum PO activity was observed at 5 min of incubation for 10 mM of DL-dopa that was considered as optimum concentration. The ideal pH and temperature for serum PO activity was observed as 7.5 and 20°C, respectively. These results suggested that standardizing a suitable substrate is an essential prerequisite to evaluate the real PO activity of serum which might significantly fluctuate in each insect model.

Serum phenoloxidase activity in the hemolymph of the anomuran crab Albunea symmysta (Linnaeus, 1758) (Decapoda: Anomura: Albuneidae)

Abstract We characterized the optimal conditions for measuring serum phenoloxidase activity and its functional activity and susceptibility to an inhibitor and various activators in an anomuran crab, Albunea symmysta (Linnaeus, 1758). The substrate affinity of the phenoloxidase (PO) enzyme was determined using different phenolic substrates in which only diphenols were found to be oxidized. The enzyme was characterized as a catecholoxidase-type of PO and 3,4-dihydroxy-DL-phenylalanine (DL-Dopa), the enzyme showing the highest substrate affinity to the serum. The optimal enzyme activity was observed at 5 mM DL-Dopa in 10 mM Tris-HCl buffer at a pH of 7.5 at 25 °C for 10 min, and absorbance at 470 nm. Serum-PO activity was inhibited by 7 mM phenylthiourea (PTU), and activated by activators such as trypsin, chymotrypsin, pronase-E, and detergent-like sodium dodecyl sulfate (SDS). We also identified the chemicals causing in vitro inhibition or activation of the enzyme as a serum of the crab having a potent PO activity.

Biofloc based technology evaluation for nutrient dense culture system for nursery and grow-out farming of Pacific white shrimp Penaeus vannamei Boone, 1931

The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio manipulation, where the system becomes bacterial dominated rather than algae dominated and takes care of the wastes generated through in situ bioremediation. Protein is utilised in two ways; as feed for the shrimp and as microbial floc when the heterotrophic microbes convert the nitrogenous wastes into protein. It also promises a healthy rearing system, which is increasingly identified as one possible solution for disease problems especially those striking at early stages. The purpose of this study was to evaluate the effect of biofloc and periphyton technology (BPT) on the growth and immunomodulatory performance of Pacific white shrimp Penaeus vannamei during nursery and grow-out culture. The experimental BPT treatments with three tier substrate system with molasses as carbohydrate (CHO) source were compared with the conventional autotrophic system. Theimmunomodulation and cumulative percentage mortality upon challenge with pathogenic strain of Vibrio parahaemolyticus were assessed in the reared animals. We have successfully demonstrated the BPT based nursery and grow-out systems for P. vannamei with the advantage of providing significantly (p<0.05) better growth performance (27.6% improvement inaverage body weight, ABW) and feed utilisation (31% improvement in feed conversion ratio, FCR). A production level of 4-4.5 kg m-3 of water was achieved through this BPT system registering a significant improvement over the conventional system (p<0.05). The Cumulative percentage mortality following pathogen challenge was significantly lower (p<0.05) in the biofloc grown shrimps compared to that of the control group, thus showing better resistance to pathogenic challenge. Furthermore, the biofloc reared shrimp did exhibit significant improvement in non-specific immune response in terms of serum phenoloxidase activity and total haemocyte counts possibly suggesting potential immunostimulatory role of the biofloc associated heterotrophic bacteria. This eco-based technology as revealed through our studies brings substantial improvement in productivity, minimising water requirement, recycling in situ nutrients and organic matter in turn improvingfarm biosecurity, augmentation of natural food, improvement of FCR and better health of the cultured shrimp.

Alternate livelihood development for ‘Aila’ affected tribal people through aquaculture in Bali Island of the Sunderban, West Bengal, India

The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio manipulation, where the system becomes bacterial dominated rather than algae dominated and takes care of the wastes generated through in situ bioremediation. Protein is utilised in two ways; as feed for the shrimp and as microbial floc when the heterotrophic microbes convert the nitrogenous wastes into protein. It also promises a healthy rearing system, which is increasingly identified as one possible solution for disease problems especially those striking at early stages. The purpose of this study was to evaluate the effect of biofloc and periphyton technology (BPT) on the growth and immunomodulatory performance of Pacific white shrimp Penaeus vannamei during nursery and grow-out culture. The experimental BPT treatments with three tier substrate system with molasses as carbohydrate (CHO) source were compared with the conventional autotrophic system. The immunomodulation and cumulative percentage mortality upon challenge with pathogenic strain of Vibrio parahaemolyticus were assessed in the reared animals. We have successfully demonstrated the BPT based nursery and growout systems for P. vannamei with the advantage of providing significantly (p<0.05) better growth (27.6% improvement in average body weight, ABW) and feed utilisation (31% improvement in feed conversion ratio, FCR). A production level of 4-4.5 kg m-3 of water was achieved through this BPT system registering a significant improvement over the conventional system (p<0.05). The cumulative percentage mortality following pathogen challenge was significantly lower (p<0.05) in the biofloc grown shrimps compared to that of the control group, thus showing better resistance to pathogenic challenge. Furthermore, the biofloc reared shrimp did exhibit significant improvement in non-specific immune response in terms of serum phenoloxidase activity and total haemocyte counts possibly suggesting potential immunostimulatory role of the biofloc associated heterotrophic bacteria. This eco-based technology as revealed through our studies brings substantial improvement in productivity, minimising water requirement, recycling in situ nutrients and organic matter in turn improving farm biosecurity, augmentation of natural food, improvement of FCR and better health of the cultured shrimp.

Changes in non-specific immune parameters of mature Chinese mittencrab (Eriocheir sinensis) in response to elevated salinities

Mature Chinese mitten crabs,Eriocheir sinensis,are exposed to brackish water or coastal waters as an obligatory part during adult reproductive migration.In this study,we investigated the changes in serum total protein and oxyhemocyanin contents,alkaline phosphatase(AKP),superoxide dismutase(SOD) and phenoloxidase(PO) activities in both mature male and female E.when in freshwater and after step-wise acclimation to the following salinities: 7,14,21,28,35.Increasing salinities caused a gradual decrease in serum total protein and oxyhemocyanin contents.Serum AKP activity was elevated slightly at 7,thereafter it dropped slowly by the end of experiment.Serum SOD activity showed a slight decrease after increase of salinity until 21,it was activated above 21.Serum PO activity decreased gradually with the increase of salinity in males;however,it maintained a stable level above 21 in females.All tested parameters in serum except for SOD were significantly higher in females than those in males.It is suggested that elevated salinity induced a decrease in serum total protein and oxyhemocyanin contents.Serum immune enzyme activities in mature E.sinensis will be affected when the salinity was near to or above 28,which could exert a negative effect on reproduction.Further studies are needed to understand the biochemical adaptation of mature E.sinensis,during their reproductive migration acclimation to elevated salinities.Sex differences should not be ignored.

Enhancement of non-specific immune response in sea cucumber ( Apostichopus japonicus) by Astragalus membranaceus and its polysaccharides

In this study, the immunostimulatory effect of oral administration of different preparations (conventional fine powder [CP] and superfine powder [SP]) of Astragalus membranaceus root or its polysaccharides (APS) in sea cucumber ( Apostichopus japonicus) was investigated. Sea cucumbers with an average initial weight of 49.3 ± 5.65 g were fed with a diet containing 3% CP or SP or 0.3% APS over a period of 60 days. The non-specific humoral (phenoloxidase, lysozyme and agglutination titer) and cellular (phagocytic capacity and reactive oxygen species) responses were determined and compared with controls (no supplement) after 20, 40 and 60 days of feeding. Variation in the levels of responses was evident among different supplements. SP and APS significantly enhanced most of the immune parameters tested. Among the humoral responses, lysozyme activity significantly increased after feeding with SP-supplemented diet for 20, 40 or 60 days. Furthermore, lectin titer showed significant enhancement after 20 and 60 days of feeding with APS-supplemented diet. Significant increase in the production of reactive oxygen species was evident for all three supplements after 20 days of feeding, but no significant change in serum phenoloxidase activity was observed for any of the three supplements over the three different periods. Overall, significant modulation of the cellular responses was only noticed after 20 days of feeding with SP- or APS-supplemented diet. After 60 days, these two groups also exhibited a decrease in the cumulative symptom rates compared to the controls when challenged with Vibrio splendidus. These results indicated that dietary intake containing A. membranaceus root or its polysaccharides could enhance the immune responses of A. japonicus and improve its resistance to infection by V. splendidus.

Immune Responses and Resistance against Vibrio parahaemolyticus Induced by Probiotic Bacterium Arthrobacter XE‐7 in Pacific White Shrimp, Litopenaeus vannamei

Abstract A 63‐d feeding experiment was conducted to determine the effects of dietary supplementation of probiotic bacterium Arthrobacter XE‐7 on immune responses and resistance against Vibrio parahaemolyticus in the Pacific white shrimp, Litopenaeus vannamei. The probiotic bacteria were administered orally at four different doses of 0, 106, 108, and 1010 colony‐forming unit (CFU)/g feed for shrimp. On Day 50, the shrimp were challenged with Vibrio parahaemolyticus by bath. On Days 7, 21, 49, and 63, six shrimp per tank were sampled to take intestine and hemolymph. With increasing dietary supplementation of probiotic bacteria, shrimp mortality decreased from 63.16% (the control) to 55.9% (106 CFU/g feed), 51.75% (108 CFU/g feed), and 51.78% (1010 CFU/g feed), respectively. Vibrio counts in intestine of shrimp fed probiotic bacterium Arthrobacter XE‐7 was generally lower than that in the control shrimp (P < 0.05). The probiotic bacteria generally increased the immune parameters in shrimp, that is, total hemocyte counts, percentage phagocytosis, respiratory burst activity, and serum phenoloxidase activity. The results showed that probiotic bacterium Arthrobacter XE‐7 can be used as probiotic in shrimp feed.

Time-related action of Lactobacillus plantarum in the bacterial microbiota of shrimp digestive tract and its action as immunostimulant

The objective of this work was to assess the time-related action of probiotic Lactobacillus plantarum in the bacterial microbiota of the digestive tract of Litopenaeus vannamei, and the relation of total haemocyte count and serum phenol oxidase activity of shrimp challenged with Vibrio harveyi. Shrimps were fed with a probiotic-supplemented diet, for eight days, then shifted to a commercial diet. Shrimps fed only with the commercial diet served as control. Evaluations were made on the 8th day of experiment and repeated two, four, six and eight days later. Total lactic bacteria in the digestive tract was higher until the 4th day of evaluation in the probiotic-supplemented group. Vibrio spp. counts were higher in the control at days zero and two. Until the 4th day of evaluation, the total haemocyte counts in shrimps after challenge with V. harveyi were higher in probiotic-supplemented group than in control group. Significant difference was not observed in phenol oxidase activity. On the 6th day after shifting from supplemented to control diet, all parameters were equal in both groups, suggesting that the time-related action of L. plantarum in shrimp is short.