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Effects of emodin and different protein levels on growth and immunity of the blunt snout bream (<em>Megalobrama amblycephala</em>) for in-pond raceway aquaculture systems
Get PDFThe present study aimed to evaluate the effects of emodin and different protein levels on growth-promoting antioxidant capacity and protein utilization of blunt snout bream to in-pond raceway aquaculture systems (IPRS). The experiment was divided into three groups: low protein group (LP) (29% low protein level), high protein group (HP) (32% high protein level), and emodin group (ED) (29% protein level + 0.05% emodin). At 210 days in the late stage of culture, the weight of the ED and HP groups was higher than the LP groups (P P P P P M. amblycephala
Chitosan Decelerates Melanosis in Shrimp: A Novel Technique for Visual Quality Assessment Using Digital Image Analysis
Get PDFThe study aimed to determine the effects of chitosan, sodium metabisulfite, and citric acid against melanosis, which causes significant economic losses during the storage of shrimps. For this purpose, two different types of chitosan were extracted from tiger prawn shell wastes. The extracted chitosan was characterized by viscosity, FT-IR, XRD, SEM imaging, and color analyses. Prevention of melanosis formation was investigated by testing chitosan, sodium metabisulfite, and citric acid. To achieve this, fresh deep-water pink shrimp samples immersed in different solutions were stored for 12 days at 4℃. Melanosis formation in the samples was observed via color measurement, sensory evaluation, and image analysis. According to the results of the research, the deacetylation degrees of chitosans were found to be 99.50 and 89.51% and 76.31 and 78.24% by two different methods, respectively. Viscosities were measured as 0.34 and 4.17 cSt, respectively. Regarding the color parameters, the L* values were 83.68 and 78.94, a* values were 0.55 and 2.71, and b* values were 10.33 and 13.85, respectively. According to the sensory evaluation conducted throughout the study, melanosis formation was observed in all groups starting from the 6th day. On the 8th day, the control groups exceeded the acceptability threshold, and on the 12th day, melanosis formation spread throughout the body in all groups. The sensory evaluation results were supported by the color measurement and image analysis implemented for the first time in this study. The present study’s results showed that chitosan obtained from shellfish wastes decelerates melanosis formation as an alternative to commercially used chemicals
Investigation of Reactive Red 198 Dye Removal by Chitosan from Aqueous Solution
Get PDFThis study used chitosan, a biopolymer with high adsorption capacity obtained from shrimp shells, to remove Reactive Red 198 dye from water. The effects of pH, temperature, dye concentration, and particle size on adsorption were investigated. The optimum pH level for the adsorption was determined as 5. The effect of the temperature was found to be adverse, and it was observed that the adsorption capacity of chitosan decreases as the temperature increases. Considering the effect of the initial dye concentration, the adsorption values of under-size chitosan (passed through a 150-mesh sieve) and over-size chitosan (retained on a 150-mesh sieve) at 200 mg/L dye concentration were 197.38 and 196.22 mg/g, respectively. At 100 mg/L dye concentration, these values were 97.41 and 96.10 mg/g, respectively. Adhesion of the Reactive Red 198 was easier because the adsorption surface area expanded with the reduction of the particle size of the chitosan. According to the results of the study, it was seen that the isotherm model of adsorption is a suitable monolayer for the Langmuir isotherm model. Langmuir isotherm's maximum adsorption capacity (Qmax) was calculated as 500 mg/g. The kinetic model was in line with the pseudo-second-order kinetic model. The FTIR spectra of the chitosan before and after adsorption showed that the adsorption is indeed chemical. Furthermore, SEM results demonstrated that the adsorption was more efficient due to the fibrous and porous structure of the chitosan
A comprehensive study in efficacy of Vietnamese herbal extracts on whiteleg shrimp (<em>Penaeus vannamei</em>) against <em>Vibrio parahaemolyticus</em> causing acute hepatopancreatic necrosis disease (AHPND)
Get PDFTraditional Vietnamese herbal species were examined for their antimicrobial activity and disease resistance in whiteleg shrimp. In-vitro screening, the extracts of ten herbs were conducted to test the inhibition ability against Vibrio parahaemolyticus, causing acute hepatopancreatic necrosis disease. The results showed that five out of ten herbal species, including Pithecellobium dulce, Melaleuca leucadendron, Eucalyptus globulus, Mimosa pirga, and Hibiscus sabdariffa displayed potent antibacterial activity. Besides, three types of extracts of H. sabdariffa, E. globulus, and M. pirga were coated to the pellet feed at a concentration of 1%. After 30 days of feeding, the whiteleg shrimp (Penaeus vannamei) were challenged by V. parahaemolyticus through immersion. The growth performance (such as growth rate in length and weight, survival rate), hematological parameters of total hemocytes (THC), hyaline hemocytes (HC), and granulocytes (GC), and hepatopancreas recovery under the treatments with herbal extracts of the whiteleg shrimp were significantly enhanced as compared with the control (without herbal extract). The mortality and the bacterial density in the hepatopancreas of shrimp decreased. Specifically, the mortality of shrimp in the treatment supplemented with the methanol extract of H. sabdariffa was the lowest, followed by M. pirga and E. globulus. The experimental results also indicated that H. sabdariffa, E. globulus, and M. pirga could improve immune parameters and disease resistance; therefore, they should be employed in sustainable shrimp, practical farming
Trematodes obtained from snails in giant gourami ponds supplied by well water in Tien Giang province, Vietnam
Get PDFA study on trematode obtained from freshwater snails in 30 grow-out giant gourami ponds supplied by well water was conducted in Chau Thanh district, Tien Giang province, Vietnam. The snails were sampled in the flooding season (October 2020), the intermediary season (January 2021) and the non-flooding season (April 2021). Eight snail species belonging to 8 genera, 4 families were found including Sermyla tornatella (48.6%), Sinotaia lithophaga (19.3%), Filopaludina sumatrensis (15.4%), Melanoides tuberculata (6.4%), Pomacea sp. (4.7%), Bithynia siamensis (4.2%), Thiara scabra (0.8%) and Tarebia granifera (0.6%). Cercariae were recovered from only two snail species of Melanoides tuberculata with Xiphidio cercariae and Furcocercous cercariae with a prevalence of 7.4%, and Bithynia siamensis with Xiphidio cercariae and Pleurolophocercous cercariae with the infection rate of 6.9%. The trematodes were found in 8 ponds (26.7%), 7 ponds (23.3%), and 3 ponds (10.0%) in the intermediary season, the non-flooding season, and the flooding season, respectively (P>0.05). More research on the epidemiology of trematodes in snails in fishponds should be done to contribute to food safety and sustainable aquaculture
Determination of Growth and Nutritional Composition of Nile Tilapia (<em>Oreochromis niloticus</em>) Fed With L-Glutamic Acid Supplemented Feeds
Get PDFThe study aimed to assess Nile tilapia's (Oreochromis niloticus) growth performance and body chemical composition through varying levels of L-Glutamic acid supplementation. In the experiment, four different groups of feed were prepared; the control C (0% L-Glutamic acid), G1 (1% L-Glutamic acid), G2 (2% L-Glutamic acid), and G3 (3% L-Glutamic acid). Tilapia juveniles with an average initial weight of 4.86 g were stocked into 12 fiberglass tanks (450L) with 40 individuals and three replications under controlled conditions, and the experiment was continued for a period of 60 days. At the end of the experiment, for the G2 group final weight (FW, 19.31±0.59 g), specific growth rate (SGR; 2.30±0.05), feed conversion ratio (FCR; 1.02±0.03), daily growth rate (DGR; 4.95±0.20) protein efficiency ratio (PER 2.83±0.10) and net protein utilization (NPU; 61.62±3.39) were better than the other groups (P<0.05). Nutritional composition data showed that the groups differed between protein, dry matter, and lipid compositions. The G2 group exhibited the highest whole-body protein level, recording a value of 21.24±0.52, whereas the control group demonstrated the lowest protein level at 20.17±0.15. In conclusion, incorporating 2% L-Glutamic acid into the diet of juvenile Nile tilapia is advisable for both the growth and development of the fish and for enhancing their nutritional composition
Report on Midden Exposed by Coastal Erosion in Lapakahi State Historical Park, North Kohala District, Hawai‘i Island
Get PDFClimate change is impacting coastal sites at an alarming rate.We report on coastal midden exposed by storm damage in the archaeological interpretive area of Lapakahi State Historical Park, North Kohala District, Hawai‘i Island, specifically, Site 50-10-02-04043, a canoe shed (halau). Site 04043 was first recorded, but not excavated, in the 1970s. Radiocarbon dating reported here suggests deposits did not begin accumulating until ca. cal AD 1700–1900, surprisingly late given its coastal location and previous dating of leeward Kohala sites. To help understand this we considered how the coastline has changed over time. We estimate, based on high-resolution airborne LiDAR bathometry, that this location was around 100m inland at the time people first arrived in the Hawaiian Islands. The subsidence of Hawai‘i Island slowly brought the coastline closer and it would have been around 10m from this location when deposits began accumulating. The contents of the midden are consistent with previous studies of subsistence in leeward Kohala.We attempted to improve on the specificity of the faunal inventory through ancient DNA but failed to recover intact DNA in fragmentary faunal bone samples. We note that reporting negative results is important for the judicious use of this technique. In sum, our results highlight the critical importance of a targeted, systematic study of early settlement—something that has never been done in the Hawaiian Islands—rather than relying on the type of salvage excavations described here