Hepatopancreas Of Pacific White Shrimp Research Articles

Long noncoding RNA profiling in hepatopancreas of Pacific white shrimp and its role in response to white spot syndrome virus infection

Long noncoding RNA (lncRNA) is a potential regulator of biological processes, including immunity, reproduction, and development. Although several transcriptome studies have focused on responses of viral infections in several organisms, the role of lncRNAs in viral responses in shrimp is still unclear. Therefore, this work aimed to identify putative lncRNAs and study their role in white spot syndrome virus (WSSV) infection in white shrimp. The hepatopancreas transcriptome from WSSV infected shrimp was analyzed in silico to identify putative lncRNAs. Among 221,347 unigenes of the de novo assembled transcriptome, 44,539 putative lncRNAs were identified, 32 of which were differentially expressed between WSSV-infected and control shrimp. Five candidate lncRNAs were validated for their expressions in shrimp tissues and in response to WSSV infection. Lnc164 was chosen for further investigation of its role in WSSV infection. Knockdown of lnc164 prolonged survival of shrimp when challenged with WSSV, suggesting a role in shrimp immunity. In addition, lnc164 was not directly involved in the control of total hemocytes and viral loads in hemolymph of WSSV-infected shrimp. A set of lnc164-regulated genes was obtained by RNA sequencing among which 251 transcripts were differentially expressed between lnc164 knockdown and control shrimp. Six immune-related genes were validated for their expression profiles. Our work sheds light on lncRNA profiles in L. vannamei in response to WSSV infection and paves the way to a functional study of lnc164 in host antiviral response.

Histopathological of the hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) infected by white feces disease

The high production of Pacific white shrimp (Litopenaeus vannamei) in Pidie Jaya impacts water quality decline around the ponds due to aquaculture waste. This condition causes shrimp to be susceptible to diseases, one of which is white feces disease (WFD). The objective of the study is to determine the level of hepatopancreatic damage caused by WFD through histopathological performance. Four shrimp samples were taken randomly from two semi-intensive ponds in Meurah Dua District, Pidie Jaya Regency, Aceh, Indonesia. The results showed that the histopathology in the hepatopancreas was severely damaged. The damages include vacuolization, fat degeneration, and necrosis in ponds with higher ammonia concentrations. According to pH, temperature, salinity, and ammonia concentrations, ponds near residential areas were more polluted than ponds far from residential areas. This condition is projected by the more damaged histopathological obstruction of the shrimp’s hepatopancreas.

Dietary copper improves growth and regulates energy generation by mediating lipolysis and autophagy in hepatopancreas of Pacific white shrimp (Litopenaeus vannamei)

Copper is an essential micronutrient for living organisms, but its biological function has not been sufficiently studied, especially in crustaceans. Therefore, the present study aimed to evaluate the role of copper in the maintenance of energy homeostasis by mediating lipid and energy metabolism in Litopenaeus vannamei. L. vannamei (initial weight 0.90 ± 0.00 g) were fed diets containing 12.4 (Cu12.4), 22.0 (Cu22.0), 31.0 (Cu31.0), 41.7 (Cu41.7) and 49.8 (Cu49.8) mg kg−1 Cu for 8 weeks. Lipid and energy metabolism-related biochemical and molecular parameters were determined, and ultrastructural observation performed in hepatopancreas. Growth performance, tissue Cu deposition, antioxidant parameters, and expression of genes involved in Cu homeostasis and autophagy were also evaluated. Dietary copper supplementation improved growth, Cu concentration in tissue, and antioxidant capacity compared to the Cu-deficient diet. Copper promoted lipolysis and β-oxidation, confirmed by elevated expression levels of cpt1, ampkγ, acbp, acadl, acadm, acadvl, acox1, acox3 and decreased expression of srebp, acc1, 6pgd, and markedly increased activities of LPS and CPT1 and decreased ACC activity. Expression levels of genes related to autophagy (atg13, atg3, atg12, atg9, beclin1) were up-regulated, and autolysosomes and autophagosome were observed in the hepatopancreas of shrimp fed diets supplemented with copper. Furthermore, energy metabolism related parameters (ATPase, cytochrome c oxidase, citrate synthase, adenosine 5′-triphosphate) and genes involved in tricarboxylic-acid cycle (cs, aco, idh, ogdh, sdhc, sdhd, fh, mdh) were up-regulated in shrimp fed copper supplemented diets. The present study showed that copper-mediated lipolysis and autophagy can coordinate energy generation, and provided new insight into copper nutrition and the potential beneficial effects of dietary Cu on energy metabolism in crustaceans.

Successive digestion of tilapia collagen by serine proteinase and proline specific endopeptidase to produce novel angiotensin I-converting enzyme inhibitory peptides

Serine proteinase, purified from the hepatopancreas of Pacific white shrimp (Litopenaeus vannamei), was used to hydrolyze acid solubilized collagen (ASC) isolated from Nile tilapia (Oreochromis sp.) skin to produce angiotensin I-converting enzyme (ACE) inhibitory peptides (ACEIPs). A series of column chromatography assays were used to separate the ACEIPs. A peptide, NPARTCR, was isolated as it exhibited high ACE inhibition potential. Further digestion of this peptide by a proline specific endopeptidase (PSEP), produced a pentapeptide ARTCR with ACE inhibitory activity (IC50) of 77.0 μmol/L. Both NPARTCR and ARTCR inhibited ACE in a non-competitive manner. An in vivo study in rats demonstrated that ARTCR has ACE inhibitory activity via lowering systolic blood pressure in spontaneously hypertensive rats (SHRs). These results suggest that processing by-products from shrimp and tilapia are ideal raw materials for the production of serine proteinase and collagen, respectively. Serine proteinase and collagen are both ideal raw materials that can be used to derive ACE inhibitory active peptides against hypertension.

Poly‐β‐Hydroxybutyrate (PHB) Improves Nursery‐Phase Pacific White Shrimp Litopenaeus vannamei Defense against Vibriosis

AbstractThis study assessed the effect of poly‐β‐hydroxybutyrate (PHB) on the growth, survival, and disease resistance of Pacific white shrimp Litopenaeus vannamei. A 20‐d feeding test using 30‐d‐postlarval Pacific white shrimp (100 shrimp/tank) tested three different diets: 0.3 g PHB/kg diet, 0.5 g PHB/kg diet, and commercial feed containing no PHB as the control. The feeding test was followed by a 10‐d bacterial challenge test using Vibrio harveyi. After the feeding test, the highest average final body weight, specific growth rate, and total biomass (mean ± SD = 0.44 ± 0.28 g, 28.82 ± 2.08%/d, and 25.91 ± 7.19 g, respectively) were found in the 0.5 g PHB/kg diet group, while the 0.3 g PHB/kg diet showed the highest survival rate (67.00 ± 8.83%). After the Vibrio harveyi challenge test, both PHB diet treatments resulted in the same significantly higher survival rate (96.66 ± 4.71%) compared with the control treatment (70.00 ± 4.71%). The highest body weight gain during the challenge test was seen in the 0.5 g PHB/kg diet group. Total abundance of heterotrophic bacteria and Vibrio spp. was relatively similar for all treatments. Histopathological analysis showed that hepatopancreas samples from PHB‐supplemented Pacific white shrimp showed decreasing tubular epithelial cell lesions as a result of Vibrio harveyi infection, suggesting that PHB protected the hepatopancreas of Pacific white shrimp from the destructive effect of Vibrio harveyi infection. Supplementation at 0.5 g PHB/kg significantly increased Pacific white shrimp survival and growth with or without Vibrio harveyi infection and, thus, has high potential for further use in Pacific white shrimp aquaculture.

Use of TPP and ATPS for partitioning and recovery of lipase from Pacific white shrimp (Litopenaeus vannamei) hepatopancreas.

Lipase recovery from Pacific white shrimp hepatopancreas using a three-phase partitioning (TPP) system in combination with an aqueous two-phase system (ATPS) was studied. TPP system was formed with a simultaneous addition of salt directly to crude extract (CE) followed by an organic solvent addition. The various process parameters required for efficient purification of lipase were optimized. The best lipase yield (87.41%) and purification fold (PF) (3.49-fold) were obtained in the interphase of TPP system, which consisted of the CE to t-butanol ratio of 1:1 (v/v) in the presence of 50% (w/v) (NH4)2SO4. Subsequently, TPP fraction was subjected to ATPS. Effects of phase compositions including PEG molecular weight and concentration, types and concentration of salts, NaCl addition and system pH on lipase partitioning were investigated. With the application of 25% (w/w) PEG1000 and 15% (w/w) MgSO4, at pH 5.0 was found most appropriate since high lipase PF (5.19-fold) and yield (78.46%) in top phase were obtained. The partitioned enzyme exhibited optimal activity at pH 8.0 and 55°C and was stable at a temperature range of 0-40°C and a pH range of 7-10. The partitioned lipase showed high tolerance in the presence of ethanol and methanol. Hence, the combined partitioning systems, TPP-ATPS, were found to be an attractive technique for the recovery and partial purification of lipase from Pacific white shrimp hepatopancreas.

Optimized synthesis of biodiesel using lipase from Pacific white shrimp (Litopenaeus vannamei) hepatopancreas

Enzymatic production of biodiesel from palm oil using partially purified lipase from the hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) as a low cost catalyst was studied. In this optimization study, the effects of reaction time, enzyme concentration, methanol/oil molar ratio, water content and reaction temperature on the biodiesel yield were considered. The best conditions for biodiesel preparation were: 70 kUnit lipase, 4:1 methanol to oil molar ratio, 3% water, 45 °C reaction temperature and a reaction time of 16 h. Under these optimal conditions, the maximum biodiesel yield reached 97.01%. The attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and thin layer chromatography (TLC) were used to ensure the conversion of palm oil into biodiesel. The biodiesel properties were within the recommended biodiesel standards as prescribed by EN 14214 and ASTM D 6751. Therefore, the lipase from the hepatopancreas of Pacific white shrimp is a potential biocatalyst for the biodiesel industry.

Comparative study on antioxidant activity of hydrolysates from splendid squid (Loligo formosana) gelatin and protein isolate prepared using protease from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei).

Antioxidative activities of splendid squid gelatin hydrolysate (SGH) and squid mantle protein isolate hydrolysate (SMPIH) with different DHs (10-50%) prepared using crude protease from hepatopancreas of Pacific white shrimp were comparatively studied. At the same DH, SGH had higher FRAP and metal chelating activity and SMPIH showed higher ABTS radical scavenging activities. However, SMPIH had higher ABTS radical scavenging activity than SGH at all DHs tested. SMPIH showed higher DPPH radical scavenging activities than SGH when DHs were up to 30% DH. However, the former had the lower activity as DHs were 40 and 50%. ABTS radical scavenging activity of SGH and SMPIH with 50% DH in gastrointestinal model system increased in the duodenal condition, while SGH showed higher activity in stomach condition than SMPIH. SGH and SMPIH (500, 1000 and 2000mg/L) could retard lipid oxidation in a lecithin liposome system in a dose dependent manner. Based on Sephadex G-25 column chromatography, the fraction with ABTS radical scavenging activity had MW of 283 and 1381Da, respectively. Therefore, both hydrolysates from squid gelatin and mantle protein isolate could be used as the alternative natural antioxidants.

Ammonia exposure induces oxidative stress, endoplasmic reticulum stress and apoptosis in hepatopancreas of pacific white shrimp (Litopenaeus vannamei).

Ammonia is one of major environmental pollutants in the aquatic system that poses a great threat to the survival of shrimp. In the present study, the mRNA expression of endoplasmic reticulum (ER) stress marker and unfolded protein response (UPR) related genes, as well as the change of redox enzyme and apoptosis were investigated in hepatopancreas of the pacific white shrimp, Litopenaeus vannamei after the exposure of 20mgL(-1) total ammonia nitrogen (TAN). Compared with the control group, the superoxide dismutase (SOD) activity in hepatopancreas decreased significantly (p<0.05) at 96h, whereas the malonyldialdehyde (MDA) concentration increased significantly (p<0.05). The mRNA expression levels of ER stress marker-immunoglobulin heavy chain binding protein (Bip) gene and key UPR related genes including activating transcription factor 4 (ATF4) and the spliced form of X box binding protein 1 (XBP1) increased significantly (p<0.05) in hepatopancreas at 96h after exposure to ammonia. In addition, apoptosis was observed obviously in the hepatopancreas of L.vannamei after exposure to ammonia by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. The results indicated that ammonia exposure could induce oxidative stress, which further caused ER stress and apoptosis in hepatopancreas of L. vannamei.

Laundry detergent-stable lipase from Pacific white shrimp (Litopenaeus vannamei) hepatopancreas: Effect of extraction media and biochemical characterization

ABSTRACTExtraction and biochemical properties of a new lipase from the hepatopancreas of Pacific white shrimp were studied. Recovery of the hepatopancreas powder with 50 mM Tris-HCl, pH 7.0 containing 0.2% (v/v) Brij35 gave a higher recovery of lipase activity than other extractants tested (p < 0.05). The optimal pH and temperature for lipase activity were 8.5 and 60°C, respectively, when p-nitrophenyl palmitate was used as a substrate. The enzyme was stable to heat treatment up to 40°C and over a pH range of 7.0–10.0 for 30–120 min. Lipase activities continuously decreased as the sodium deoxycholate (NaDC) concentration increased, but activities increased as NaCl concentration increased up to 3.0 M. Hydrolytic activity was enhanced by NaN3, but strongly inhibited by Hg2+, Cu2+, Al3+, and phenylmethanesulfonyl fluoride. The lipase was evaluated as highly stable against surfactants (Tween 20, Tween 80, Triton X-100, and gum arabic). However, the enzyme was unstable against sodium dodecyl sulphate. Stability of the lipase with commercial liquid and solid detergents (Attack®, Bres®, Omo®, and Pao®) was also investigated. The lipase exhibited substantial stability and compatibility with tested commercial liquid and solid laundry detergents for 30–60 min. The overall properties of the lipase from Pacific white shrimp hepatopancreas, thus leading us to propose that it is an excellent candidate for use as biocatalysts for better detergent formulation.

Comparative Study on Virgin Coconut Oil Extraction Using Protease from Hepatopancreas of Pacific White Shrimp and Alcalase

Virgin coconut oil (VCO) was extracted from coconut milk with the aid of crude protease extract (CPE) from hepatopancreas of Pacific white shrimp at different levels (5–15 unit/g protein) at 60C for various hydrolysis times (0–180 min). Yield of VCO increased within the first 90 min (P < 0.05). However, Alcalase showed higher efficacy in VCO extraction, compared with CPE and the control (without enzyme) (P < 0.05). No differences in lipid oxidation of all VCOs extracted by different proteases were observed (P > 0.05). Alcalase and CPE increased the creaming index and induced the collapse of oil droplets in coconut milk, as determined by the confocal laser scanning microscopy and the phase contrast microscopy. VCOs contained medium chain fatty acid, especially lauric acid (C12:0), as the most abundant fatty acid, followed by myristic acid (C14:0). Therefore, VCO could be extracted using CPE or Alcalase at the optimal temperature (60C) for 90 min. Practical Applications Pacific white shrimp hepatopancreas has been known as a potential source of trypsin that can be used to hydrolyze proteins stabilizing emulsion in coconut milk. Trypsin from Pacific white shrimp hepatopancreas could therefore serve as a potential aid for virgin coconut oil extraction with the shorter processing time, particularly when applied under the optimal condition. As a consequence, the cost associated with commercial enzymes could be reduced and the prime quality of virgin coconut oil was still obtained.

Astaxanthin degradation and lipid oxidation of Pacific white shrimp oil: kinetics study and stability as affected by storage conditions

The kinetics of astaxanthin degradation and lipid oxidation in shrimp oil from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) as affected by storage temperature were studied. When shrimp oil was incubated at different temperatures (4, 30, 45 and 60 °C) for 16 h, the rate constants (k) of astaxanthin degradation and lipid oxidation in shrimp oil increased with increasing temperatures (p < 0.05). Thus, astaxanthin degradation and lipid oxidation in shrimp oil were augmented at high temperature. When shrimp oils with different storage conditions (illumination, oxygen availability and temperature) were stored for up to 40 days, astaxanthin contents in all samples decreased throughout storage (p < 0.05). All factors were able to enhance astaxanthin degradation during 40 days of storage. With increasing storage time, the progressive formation of primary and secondary oxidation products were found in all samples as evidenced by the increases in both peroxide values (PV) and thiobarbituric acid reactive substances (TBARS) (p < 0.05). Light, air and temperatures therefore had the marked effect on astaxanthin degradation and lipid oxidation in shrimp oils during the extended storage.

Histopathology of the Hepatopancreas of Pacific White Shrimp, Penaeus vannamei from None Early Mortality Syndrome (EMS) Shrimp Ponds

Histopathology of the Hepatopancreas of Pacific White Shrimp, Penaeus vannamei from None Early Mortality Syndrome (EMS) Shrimp Ponds

Chemical compositions and properties of virgin coconut oil extracted using protease from hepatopancreas of Pacific white shrimp

Virgin coconut oil (VCO) was extracted from coconut milk with the aid of crude protease extract (CPE) from hepatopancreas of Pacific white shrimp at different levels (5–15 U/g protein) for various hydrolysis times (0–24 h). Yield of VCO increased within the first 6 h. The use of CPE exhibited similar extraction efficiency to the typical fermentation process. However, lipids extracted with fermentation process underwent oxidation to a higher extent, compared with those extracted using CPE. CPE increased the creaming index and induced the collapse of oil droplets in coconut milk, as determined by the phase contrast microscope. VCO contained medium chain fatty acid (MCFA), especially lauric acid (C12:0), as the most abundant fatty acid, followed by myristic acid (C14:0). Therefore, VCO could be extracted using CPE at room temperature for 6 h, in which the extraction yield was increased and lipid oxidation was negligible.Practical applications: Pacific white shrimp hepatopancreas can be a major source of proteases, especially trypsin, that can be used for hydrolysis of lipoprotein or to destabilize emulsion. Proteases from shrimp hepatopancreas could be used as a promising processing aid for virgin coconut oil extraction, in which the cost associated with commercial enzymes could be reduced and the proteases from shrimp processing byproducts were better exploited. The proteases from shrimp hepatopancreas can therefore be of benefit for the virgin coconut oil processing enterprise or industry by increasing extraction efficacy via destabilzation of coconut milk emulsion.Proteases from Pacific white shrimp hepatopancreas can be used as the aid for VCO extraction via the accelerated emulsion destabilization without any negative effect on quality.

Purification and Characterization of Trypsin from Hepatopancreas of Pacific White Shrimp

Trypsin from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) was purified to homogeneity using ammonium sulfate precipitation and a series of chromatographies including diethylaminoethyl sepharose and soybean trypsin inhibitor sepharose 4B columns. Trypsin was purified to 50.4-fold with a yield of 13.7%. Based on native-polyacrylamide gel electrophoresis (PAGE), the purified trypsin showed a single band. Trypsin had a molecular weight of 24 kDa as estimated by sodium dodecyl sulphate-PAGE. The optimal pH and temperature for α-N-benzoyl-dl-arginine-p-nitroanilide (BAPNA) hydrolysis were 8.0 and 60C, respectively. Trypsin was stable to heat treatment up to 60C and over a pH range of 7.0‐11.0. The activity was strongly inhibited by soybean N-ρ-tosyl-L-lysine chloromethyl ketone. Purified trypsin had Michaelis‐Menten constant (Km) and catalytic constant (kcat) of 1.60 mM and 3.33 s −1 , respectively, when BAPNA was used as the substrate. Trypsin with high kcat indicated its high capacity of hydrolysis and it could serve as a promising protease.

Nitric oxide as an antimicrobial molecule against Vibrio harveyi infection in the hepatopancreas of Pacific white shrimp, Litopenaeus vannamei

Nitric oxide (NO) is a key effector molecule produced in the innate immune systems of many species for antimicrobial defense. However, how NO production is regulated during bacterial infection in invertebrates, especially crustaceans, remains poorly understood. Vibrio harveyi, a Gram-negative marine pathogen, is among the most prevalent and serious threats to the world's shrimp culture industry. Its virulence typically manifests itself through shrimp hepatopancreas destruction. In the current study, we found that NO generated by an in vitro donor system (NOC-18) could rapidly and effectively kill V. harveyi. In addition, injection of heat-killed V. harveyi increased the concentration of NO/nitrite and the mRNA expression of nitric oxide synthase (NOS) in the hepatopancreas of Pacific white shrimp (Litopenaeus vannamei), the commercially most significant shrimp species. Live V. harveyi challenge also induced NO/nitrite production and NOS gene expression in primary L. vannamei hepatopancreatic cells in a time- and dose-dependent manner. Co-incubation of l-NAME, an inhibitor selective for mammalian constitutive NOSs, dose-dependently blocked V. harveyi-induced NO/nitrite production, without affecting V. harveyi-induced NOS mRNA expression. Furthermore, l-NAME treatment significantly increased the survival rate of infecting V. harveyi in cultured primary hepatopancreatic cells of L. vannamei. As a whole, we have demonstrated that endogenous NO produced by L. vannamei hepatopancreatic cells occurs in enzymatically regulated manners and is sufficient to act as a bactericidal molecule for V. harveyi clearance.

Impact of enzymatic method using crude protease from Pacific white shrimp hepatopancreas on the extraction efficiency and compositions of lipids

Lipids from striped catfish muscle were extracted with the aid of crude protease extract (CPE) from hepatopancrease of Pacific white shrimp at different levels (5–15unit/g protein) for various hydrolysis times (0–180min) at 60°C. Yield of lipids increased within the first 30min and was in agreement with increasing degree of hydrolysis. The increases in phospholipid and free fatty acid content were observed with hydrolysis times up to 30min (p<0.05). Yield of lipid increased when 50mM CaCl2 was combined with CPE. CPE exhibited similar extraction efficiency to Alcalase. However, the lower yield was obtained in comparison with the solvent extraction. Higher oxidation and hydrolysis were found in lipids extracted with the aid of CPE and Alcalase, compared with those found in lipid extracted using solvents (p<0.05). All lipid samples had triglyceride as the major component and were rich in palmitic acid and oleic acid.

Oxidative stability of lipids from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) as affected by essential oils incorporation

Oxidative stability of lipids from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) added with different essential oils at 200 ppm during 10 days of storage was studied. With increasing storage time, the progressive formation of hydroperoxide was found in all samples as evidenced by the increases in peroxide values (PV) (p&lt;0.05). Amongst all essential oils tested, lemon essential oil exhibited the highest preventive effect against oxidation, followed by plai and basil essential oils, respectively. The increases in thiobarbituric acid reactive substances (TBARS) and ρ‐anisidine value (AnV) of lipids were noticeable when storage time increased (p&lt;0.05). The increases in TBARS and AnV were retarded in the presence of essential oils. Nevertheless, the effectiveness for prevention of lipid oxidation of all three essential oils was slightly lower than α‐tocopherol when used at the same level. The formation of volatile compounds and rancid odour of samples were lowered when being incorporated with essential oils. Based on sensory evaluation, lipid containing lemon essential oil had a similar rancid odour to that added with α‐tocopherol. Thus, essential oils could be used as natural antioxidants to retard lipid oxidation and rancidity of lipids from hepatopancreas during extended storage.Practical applications: Shrimp hepatopancreas, a byproduct from shrimp processing industries, is an important source of lipids and astaxanthins, which are susceptible to oxidation. Their changes are associated with development of off‐odour and loss of nutritive value. Therefore, the uses of natural antioxidants, especially essential oils, can be a potential means to retard lipid oxidation and rancidity of shrimp oil during extended storage.Essential oils could be used as natural antioxidants to retard lipid oxidation and rancidity of lipids from hepatopancreas during extended storage.

Use of the combined phase partitioning systems for recovery of proteases from hepatopancreas of Pacific white shrimp

Recovery of proteases from hepatopancreas of Pacific white shrimp using three-phase partitioning (TPP) system in combination with aqueous two-phase system (ATPS) was investigated. TPP was performed using t-butanol with different crude protease extract (CPE)/t-butanol ratios. The interphase of system comprising CPE and t-butanol with a ratio of 1:1 in the presence of 30% ammonium sulphate yielded the highest purification fold (PF) (2.6-fold) with the recovery of 76.0%. Subsequently, TPP fraction was subjected to ATPS. Effects of phase compositions including PEG molecular weight (MW) and concentration as well as types and concentration of salts on partitioning of proteases were studied. ATPS comprising PEG1000 (15%, w/w) and magnesium sulphate (25%, w/w) provided the best condition for the maximal partitioning of proteases into the top phase and gave the highest PF (8.6-fold). The yield of 65.5% was obtained. ATPS fraction was further mixed with PEG8000 and several salts for back extraction (BE). BE using 25% PEG8000 and 10% MgSO4 gave the highest PF (9.9-fold) with the yield of 46.2%. Based on electrophoresis and activity staining, the fractionated proteases had the MW of 36 and 26kDa. Therefore, the combined partitioning systems, TPP–ATPS–BE, could be effectively used to recover and purify proteases from hepatopancreas of Pacific white shrimp.

Extraction and Stability of Carotenoid-Containing Lipids from Hepatopancreas of Pacific White Shrimp (Litopenaeus vannamei )

Impacts of extraction conditions on lipid and carotenoid yields from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) were investigated. Among single solvents (acetone, isopropanol and hexane) and their mixtures, a mixture of hexane and isopropanol (50:50, v/v) rendered lipids with the highest carotenoid yield (336.40 mg/kg hepatopancreas) with the extraction yield of 18.22% (w/w hepatopancreas) (P < 0.05). The use of hepatopancreas to solvent ratio of 1.0:4.5 (w/v) and three repetitions showed the highest carotenoid yield (363.94 mg/kg hepatopancreas) with the extraction yield of 18.08% (w/w hepatopancreas). Astaxanthin, astaxanthin diester and canthaxanthin were the major carotenoids found in lipids. When astaxanthin (2 mg/g lipid) was added into lipid, the oxidation was lowered, in comparison with the control during the storage at 30C for 10 days as indicated by lower ρ-anisidine value. Fourier transform infrared spectra study also revealed that triglyceride in lipids underwent oxidation to a lower degree when astaxanthin was incorporated. Practical Applications Shrimp hepatopancreas, a by-product from shrimp-processing industries, is one of the important sources of lipids and natural carotenoids, which are susceptible to oxidation. Their changes are associated with development of off-odor and loss in nutritive value. The recovery of lipid and carotenoid from hepatopancreas by an appropriate means would increase the revenue for shrimp-processing industries. Additionally, those value-added products could serve as the excellent source of nutrients as well as bioactive compounds.