Hepatopancreas

The aim was to elucidate the effects of elevated temperature on growth performance, growth- and appetite-regulating hormones and metabolism in Atlantic salmon, Salmo salar. Post-smolts in seawater (average mass 175g) that had been reared at 12°C were kept at three temperatures (8, 12 and 18°C) and sampled after one and three months. After three months, the fish kept in 18°C had decreased growth rate and condition factor, and elevated plasma levels of growth hormone (GH) and leptin, compared with fish kept at the lower temperatures. Food conversion efficiency was also decreased at 18°C, while at the same time protein uptake was improved and thus was not a limiting mechanism for growth. Redistribution of energy stores in fish at the highest temperature is evident as a preference of maintaining length growth during times of limited energy availability. NMR-based metabolomics analyses of plasma revealed that several metabolites involved in energy metabolism were negatively affected by temperature in the upper temperature range of Atlantic salmon. Specifically, the high temperature induced a decline of several amino acids (glutamine, tyrosine and phenylalanine) and a shift in lipid metabolism. It appears likely that the decreased food intake at the highest temperature is linked to an anorexigenic function of leptin, but also that the decreased food intake, feed conversion efficiency and condition factor can be linked to changes in GH endocrinology.Copyright © 2012 Elsevier Inc. All rights reserved.

Carotenoprotein from shells of Pacific white shrimp (Litopenaeus vannamei) was extracted with the aid of proteases from hepatopancreas of the same species at various levels
(5–30 units/g shrimp shell) for different times (0–180 min). Recovery of carotenoprotein increased with increasing protease levels and hydrolysis times, but mainly reached the plateau at 120 min of hydrolysis. Carotenoprotein contained astaxanthin and astaxanthindiester as major carotenoids. Carotenoids extracted from carotenoprotein showed increasing
ABTS, DPPH radical scavenging activities, FRAP and metal chelating activity when the concentrations increased up to 5 mg/ml (po0.05). Carotenoprotein consisted of 73.58% protein, 21.87% lipids and 2.63% ash contents. It was rich in essential amino acids and Asp/Asn and Glu/Gln were found as dominant amino acids. Therefore, carotenoprotein from shell of Pacific white shrimp could be successfully extracted using shrimp hepatopancreas proteases and could serve as the value-added nutritive food ingredients or as the animal feed

Compositions and yield of lipids extracted from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) subjected to autolysis at 60 C for different times (0, 30, 60, 90 120 and 150 min) were investigated. Extraction yield increased from 7.4% to 8.8% as autolysis time increased from 0 to 150 min. Coincidental increase in total carotenoid content was obtained with increasing autolysis time (p < 0.05). The increases in thiobarbituric acid-reactive substances (TBARS) and p-anisidine value (AV) of lipids were noticeable when autolysis time increased (p < 0.05). However, no changes in free fatty acid (FFA) content were observed within the first 60 min of autolysis (p > 0.05), but subsequently increased up to 150 min. (p < 0.05). No differences in fatty acid profiles of lipids extracted from hepatopancreas without and with 60 min prior autolysis were observed. Lipids extracted contained docosahexaenoic acid (DHA; C22:6(n  3)) as the most abundant fatty acid, followed by eicosapentaenoic acid (EPA; C20:5(n  3)). Therefore, prior autolysis at 60 C for 60 min increased the extraction yield without negative effect on lipid quality.

Antioxidative activities of hydrolysates from skin of seabass (Lates calcarifer) with different degrees of hydrolysis (DH: 10–40%) prepared using an ammonium sulphate precipitated fraction (ASPF) from Pacific white shrimp hepatopancreas and commercial Alcalase were compared. The hydrolysate prepared using ASPF or Alcalase had increases in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidative power (FRAP) as DH increased (P < 0.05). When the hydrolysate prepared using ASPF with 40% DH was subjected to a gastrointestinal model system (GIMs), ABTS radical scavenging activity and chelating activity increased, especially in the duodenal condition. The hydrolysate
(500–2000 mg/L) could inhibit lipid oxidation in a lecithin liposome system in a dose dependent manner. Based on gel filtration using a Sephadex G-15 column, peptide with
a molecular weight of 364 Da showed the strongest ABTS radical scavenging activity. Therefore, the extract from hepatopancreas could be used to increase DH of hydrolysate from seabass skin.

Improved methods of cell culture from eye stalk, hepatopancreas, muscle, ovary, and hemocytes of shrimp (Penaeus vannamei) were established using synthetic media and shrimp muscle extract (SME). For hemocytes and ovarian cell cultures, Grace’s insect medium supplemented with 10% (v/v) fetal bovine serum and 10% SME (v/v) showed enhanced attachment and proliferation of the cells. The hemocyte and ovarian cell cultures could be maintained for 48 and 66 days, respectively, and have been sub-cultured four and six times, respectively. Both ovary and hemocyte cell cultures contained primarily epithelial-like cells. Cells derived from ovary tissue grew preferably between 26°C and 28°C with 5% CO2. Although the temperature preference of hemocyte cells was the same as ovarian cells, CO2 supplementation did not show any difference in the growth of hemocyte cells. When the shrimp were injected with lipopolysaccharide (8 μg/g of shrimp) and hemolymph was drawn 24 h post-injection, the in vitro multiplicity of hemocytes dramatically improved. The growth of eye stalk, hepatopancreas, and muscle-derived cells was much less compared to ovarian cells and hemocytes under the conditions described above. The optimal culture conditions for ovarian cells and hemocytes were also different from that for eye stalk, hepatopancreas, and muscle cell culture. The proliferation efficiencies of primary cultures of hepatopancreas, eyestalk, and muscle cells were about 30, 12, and <7 d, respectively. The improved culture conditions described here, particularly for hemocytes and ovary, will be very useful for in vitro studies involving viruses infecting shrimp and in shrimp genomic studies.

Freshwater crayfish Cherax quadricarinatus have a high commercial value and are cultured in farms where they are potentially exposed to pesticides. Therefore, we examined the sublethal effects of a 50-day exposure to glyphosate acid and polyoxyethylenamine (POEA), both alone and in a 3:1 mixture, on the growth and energetic reserves in muscle, hepatopancreas and hemolymph of growing juvenile crayfish. Exposure to two different glyphosate and POEA mixtures caused lower somatic growth and decreased muscle protein levels. These effects, caused by both compounds interacting in the mixture, could also be synergistic because they were expressed even at the lowest concentration. The decrease in protein levels could be related to the greater use of other energy reserves. This hypothesis is supported by the decrease in muscle glycogen stores due to glyphosate exposure and the decrease in lipid reserves associated with exposure to POEA.

Lipids from striped catfish muscle were extracted with the aid of crude protease extract (CPE) from hepatopancrease of Pacific white shrimp at different levels (5–15 unit/g protein) for various hydrolysis times (0–180 min) at 60 C. Yield of lipids increased within the first 30 min 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 30 min (p < 0.05). Yield of lipid increased when 50 mM 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.

The lethal concentration of nitrite to the Chinese mitten crab Eriocheir sinensis was tested by exposing the animals to 17.78, 23.71, 31.62, 42.17, and 56.23 mg NaNO2 L(-1) at 20 degrees C for 24, 48, 72, and 96 h. The corresponding LC50 value for each time exposure was 43.87 (38.70-51.70), 40.24 (34.88-46.01), 38.87 (33.72-46.01) and 38.87 (33.72-46.01) mg NaNO2 L(-1) or 29.25 (25.80-34.47), 26.83 (23.25-30.67), 25.91(22.48-30.67), 25.91(22.48-30.67) mg NO2-N L(-1), respectively. The physiological response of the crab to nitrite toxicity was further investigated by exposing the crab to 0, 10, 20, 30 and 40 mg NaNO2 L(-1) for 2 d. The changes of nitrogenous compounds in haemolymph, oxyhemocyanin and metabolism were measured at 3, 6, 24 and 48 h upon exposure. Haemolymph nitrite was significantly enhanced by the increase of nitrite from 10 to 40 mg NaNO2 L(-1) during the 2-day exposure. The concentrations of nitrate, urea and glutamate in haemolymph increased concomitantly with the exposing time and ambient nitrite levels, suggesting that the formation of nitrate, urea and glutamine may be the possible end products of nitrite detoxification in crabs. The diffusion of nitrite caused a reduction of oxyhemocyanin, resulting to hypoxia in tissues. Under a hypoxia condition, crabs increased energy demand for metabolism as indicated by the elevated levels of glucose and lactate in haemolymph. Our data showed that ambient nitrite could affect oxygen carrying capacity through oxyhemocyanin reduction and the increase of energy catabolism in crabs. This study suggests that nitrite could be detoxified through the pathway of nitrate, urea and glutamine formation in crabs.

Spiny lobster Panulirus homarus which had been exposed to cupric ion at 9.55 and 19.1 μg/l for 28 days was examined for sub-lethal effects including morphology, wet weight, and induced genotoxic effect on the chromosome. Following cupric exposure, the color of lobster P. homarus changed from yellowish-brown to greenish black in the hepatopancreas, changed from normal creamy white to yellowish white in the muscle, and changed to greenish black in the gill. A significant change in the percentage of wet weight of muscle (28.70 ± 0.41–23.47 ± 0.45), hepatopancreas (4.03 ± 0.12–2.63 ± 0.17), and gills (3.63 ± 0.45–3.87 ± 0.12) were observed in the copper-treated lobsters. The diploid number of chromosomes of P. homarus was over 200 metaphases from ten lobsters, as 2n = 58, and consisted of 16 acrocentric, seven metacentric, and six sub-metacentric chromosomes. The lobsters exposed to cupric ion at 9.55 and 19.1 μg/l showed different types of chromosomal aberrations such as centromeric gaps, chromatid breaks, centromeric fusion, stickiness, ring chromosomes, and acrocentric association region. The frequency of aberrations increased with duration of exposure. In conclusion, it was suggested that cupric ion interacts with the spindle formation and consequently distorts the normal karyomorphology, indicating cytogenetic effect on lobster.

To evaluate the use of the freshwater bivalve Hyridella australis as a potential biomonitor for zinc contamination in freshwater sediments, the bioavailability and toxicity of zinc contaminated sediments (low 44 ± 5, medium 526 ± 41, high 961 ± 38 μg/g dry mass) were investigated in laboratory microcosms for 28 days by examining H. australis exposure-dose-response relationships. Zinc concentrations in sediments and surface waters were measured as zinc exposure. Zinc in whole organism soft body tissues and five individual tissues were measured as organism zinc dose. Sub-cellular localisation of zinc in hepatopancreas tissues was investigated to further understand the zinc handling strategies and tolerance of H. australis. Total antioxidant capacity, lipid peroxidation and lysosomal membrane stability were measured in hepatopancreas tissues as zinc induced biomarker responses. Accumulated zinc concentrations in whole body tissues of H. australis reflected the zinc exposure and exhibit...

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 26 kDa. Therefore, the combined partitioning systems, TPP–ATPS–BE, could be effectively used to recover and purify
proteases from hepatopancreas of Pacific white shrimp.

Between January and March 2006, suspected outbreaks of white tail disease were observed in post-larvae and juveniles of Macrobrachium rosenbergii in hatcheries and nursery ponds at Kaohsiung and Pingtung Counties in southern Taiwan. Pathognomonic lesions showed the presence of large oval and/or irregular basophilic, cytoplasmic inclusion bodies in the infected muscles and hepatopancreas. Reverse transcriptase polymerase chain reaction (RT-PCR) assay and in situ hybridization (ISH) revealed evidence of M. rosenbergii nodavirus (MrNV) infection but did not detect extra small virus. Phylogenetic analysis indicated that there were very high identities between nucleotide sequences among six strains obtained in this study (99.5–100%), moderate identities with Caribbean and Indian strains (98.2–98.6%), but slightly lower identity with a Chinese strain (95.2%). This is the first confirmation of MrNV in giant freshwater prawns, using an RT-PCR and ISH, in Taiwan.