Commercial Shrimp Research Articles

Đánh giá hiệu quả ứng dụng bộ chế phẩm probiotic BIDI-AGRI và BIDI-AQUA trong nuôi tôm thẻ chân trắng thương phẩm

Whiteleg shrimp (Litopenaeus vannamei) farming is a major economic sector in many countries worldwide. Infectious diseases and environmental pollution in shrimp ponds have resulted in significant economic losses for the aquaculture industry. This study presented the effects of a BIDI-AGRI and BIDI-AQUA probiotic blend consisting of Bacillus subtilis, Bacillus tequilensis, Bacillus amilolyquefaciens, Bacillus licheniformis, Lactobacillus acidophilus, Saccharomyces cerevisiae in shrimp cultured water treatment and shrimp growth. The BIDI-AGRI and BIDI-AQUA were applied in three commercial whiteleg shrimp ponds with surface areas ranging from 700 to 1200 m² for 90 days. Results showed that compared to the control, BIDI-AGRI and BIDI-AQUA improved several water quality parameters, including H₂S, NH₃, and COD concentrations, controlled Vibrio spp. populations within acceptable limits and enhanced shrimp immunity. Furthermore, shrimp ponds treated with BIDI-AGRI and BIDI-AQUA exhibited higher growth rates and yields. Due to lower investment costs and higher revenue, shrimp ponds using BIDI-AGRI and BIDI-AQUA achieved approximately 1.6 times higher profits compared to ponds using commercially available probiotics.

Nutritional Innovation Using Green Seaweed (Ulva sp.) and Garlic Powder Extracts for White-Leg Shrimp (Litopenaeus vannamei) Challenged by Vibrio harveyi.

This study aimed to determine the antimicrobial effects of ethanolic extracts of Ulva sp. and garlic (Allium sativum) powder ethanolic extracts against Vibrio harveyi in vitro. The stimulatory effects of Ulva sp. extract (UE) and garlic powder extract (GPE) on the growth performance and innate immune responses of white-leg shrimp, Litopenaeus vannamei, and their challenge against V. harveyi infection were also investigated. A commercial shrimp diet (36.1% protein) was enriched with 0.5, 1.0 and 2.0gUE/kg diet and 2, 4 and 6gGPE/kg diet, whereas the control group was free of any supplement. Health juveniles of L. vannamei (average weight 2-3g) were distributed in 21 fiberglass reinforced plastic (FRP) tanks (500-L capacity) at a stocking density of 300 animals/tank to represent each treatment in triplicate. The animals were fed ad libitum on the experimental diets up to satiety four times daily for 60 days. The phytochemical analysis of ethanolic extracts of Ulva sp. and garlic powder evoked their richness of several bioactive compounds showing significant antibacterial activity against V. harveyi. The GPE exhibited a higher inhibition zone than that of the UE. The supplemented diets did not significantly affect weight gain %, final weight, feed conversion ratio, specific growth rate and survival rates of white shrimp compared to those fed on the control diet. Significant increases were observed in total haemocyte count, phagocytosis and phagocytic index of all treatments compared with the control group. There were significant increases in serum total protein, acid phosphatase activity, alkaline phosphatase, lysosomal enzyme activity, phenoloxidase activity and superoxide dismutase activity with offered diets with increasing the levels of ethanolic extracts of Ulva sp. and garlic powder up to 2.0gUE/kg diet and 6gGPE/kg diet, respectively. The ethanolic extraction of Ulva sp. and garlic powder-supplemented diet groups, particularly at treatments of 2.0 and 6gGPE/kg diet, respectively, significantly reduced the shrimp mortality induced by V. harveyi infection when compared with the control group. The net results evoked that ethanolic extraction of Ulva sp. (2.0gUE/kg) and garlic powder (6gGPE/kg diet) enhanced the immune response and disease resistance of the white-leg shrimp, L. vannamei. It is also noted that the GPE is more efficient than the UE in vitro and in vivo investigations.

Extraction and Quality Control of Chitin and Chitosan from Shrimp (Vanami) Litophenause Vanamei Shells Wastes

Objective/Background: The biological value of chitin and chitosan obtained from shrimp, such as physiological compatibility, non-toxicity, bio digestibility, absorption and chelating capacity, depends on qualitative parameters that are directly related to raw material source. This study was carried out to investigate extraction and characterization of chitin and chitosan from shrimp Litophenause vanamei shells wastes. Methods: Chitin and chitosan was extracted and characterized from shrimp L. vanamei shells found in Iran, using conventional methods of pretreatment, demineralization, and deacetylation. In this study, commercial shrimp L. vanamei shell was used to extract chitin and chitosan. Results: The degree of deacetylation of shrimp chitosan (49%) is directly related to solubility of chitosan. Chitosan is considered to have excellent biological value with these qualitative parameters. The yield of shrimp chitosan was 13.96%. Conclusion: These results showed that use of shrimp shell waste to produce chitin and chitosan will have more economic and biological value along with reducing environmental pollution.

A Review and Meta-Analysis of Genotype by Environment Interaction in Commercial Shrimp Breeding.

(1) Background: Genotype-by-environment interaction (G×E) can adversely impact genetic improvement programs. The presence of G×E is mainly measured as the genetic correlation between the same trait measured in different environments where departure from unity can be taken as presence of G×E. (2) Methods: To understand the extent of G×E in shrimp production, a review and meta-analysis was conducted using the results from 32 peer-reviewed studies. (3) Results: Of these, 22 G×E studies were conducted on Pacific white shrimp (Litopenaeus vannamei) with fewer studies reported in other shrimp species. The most frequently studied traits were growth and survival, with relatively few studies on traits of economic importance. The meta-analysis demonstrated a moderately high genetic correlation (rg = 0.72 ± 0.05) for growth, indicating low to moderate levels of G×E with some re-ranking of breeding values across environments. However, substantial G×E was evident for survival where only a moderate genetic correlation (rg = 0.58 ± 0.07) was observed for survival across different environments. A re-ranking of breeding values is likely for this trait and genetic improvement of shrimp for survival in one environment may not be effective in other environments. The results from ANOVA-based studies show that G×E accounted for 6.42 ± 1.05% and 7.13 ± 3.46% of the variation for growth and survival traits, respectively. (4) Conclusion: The significance of G×E necessitates tailored genetic improvement programs in commercial shrimp breeding. We discuss the scope and challenges of G×E for shrimp breeding programs, including opportunities of implementing G×E in genomic selection programs.

"The Hotel of 10,000 Stars": The Impact of Social-Structural Determinants of Health Among Im/migrant Shrimpers in the Gulf of Mexico.

Objectives. To identify appropriate interventions to prevent injury, we conducted a qualitative study among commercial shrimp fishermen in the Gulf of Mexico. Methods. Using qualitative and participatory research methods, including interviews, photovoice, and workplace observations in southeast Texas and the Rio Grande Valley in Texas, we examined the social‒structural dimensions that contribute to physical and psychological injury. Results. We found that multiple layers of vulnerability and danger exist among shrimpers with interacting themes: (1) recognizing risk, (2) precarious employment, and (3) psychological distress. Conclusions. Our results add to the growing body of knowledge that emphasizes the negative health impacts of underregulated, high-risk, and physically demanding work performed primarily by im/migrants. Public Health Implications. Our findings highlight the larger social‒structural conditions and context of hardships endemic to migrant labor and suggest implications for practice and policy interventions. (Am J Public Health. 2024;114(8):824-832. https://doi.org/10.2105/AJPH.2024.307696).

Prokaryotic and eukaryotic microbial community dynamics in biofloc systems supplemented with non-starch polysaccharides

Biofloc technology has been developed as a sustainable system in aquaculture, which uses microbial processes to remove nutrients from the water and convert them into microbial biomass. For optimal performance, the addition of carbohydrates is essential, while their type can regulate microbial activity and composition. Specifically, we hypothesize that dietary supplementation of wheat bran, containing indigestible carbohydrates such as non-starch polysaccharides, can provide complex substrates supporting diverse microbial communities within the biofloc. In this study, we investigated how higher dietary wheat bran input affected the biofloc prokaryotic and eukaryotic microbial communities in Pacific white shrimp (Litopenaeus vannamei) culture. Two pelleted diets were made: a control diet (CONdiet) with a composition similar to a commercial shrimp diet, and a diet rich in non-starch polysaccharides (WBdiet), which was created by adding wheat bran to the control diet ingredient mix, before pelleting. These two diets were fed isonitrogenous to the shrimp for 42 days, and sampling of the biofloc was performed every three weeks. The results showed shifts in both the alpha and beta diversity in biofloc during the experiment. Diet had a significant effect on the prokaryotic community composition in the biofloc at the end of the culture period, with several genera being enriched in biofloc tanks fed the WBdiet such as Muricauda, Pirellula, and Cyanobacteriaceae. Regarding the eukaryotic communities, overall, only a few taxa were significantly affected within the WBdiet, belonging to the Trebouxiophyceae and Suillus groups. Interestingly, when feeding the WBdiet, the biofloc microbial communities exhibited predicted functionalities that were more abundant in carbohydrate metabolism, and specifically related to pentose, fructose, mannose and galactose metabolism. These results provide a basis for the control of biofloc microbial communities by using ingredients rich in plant-derived non-starch polysaccharides which shrimp cannot digest but are good energy source for the microbiota in the biofloc.

Contaminants in shrimp probiotics - a potential emerging threat to food security

Probiotics are used widely in shrimp aquaculture to improve growth and prevent disease; however, for the most part their safety and efficacy remains largely unknown. Shrimp aquaculture may be vulnerable to the negative effects of unsafe and ineffective commercial products, such as the transfer of shrimp and human pathogens and antibiotic resistance genes. Shrimp health may also be adversely affected by the use of these products, potentially leading to crop yield losses. Here, we used 16S amplicon sequencing to identify the bacterial genera present in commercial shrimp probiotics and assess this against their listed product content. We identified the presence of additional genera to the labelled contents including Escherichia/Shigella and Enterococcus that may pose a risk of disease to animals and potentially humans that come into contact with these products, as well as potentially acting as carriers for virulence and antimicrobial resistance genes. Our results suggest that some commercial shrimp probiotics may be misleading to consumers and potentially unsafe for shrimp, people and the environment. We highlight the risks that contaminated commercial probiotics may pose to food security and present a series of safety and efficacy considerations to support the sustainable use of commercial shrimp probiotics.

Physiological effects of feeding whiteleg shrimp (Penaeus vannamei) with the fresh macroalgae Chaetomorpha clavata

In shrimp farming, the use of commercial feed can generate high nutrient loads in water bodies, and often constitute the most substantial component of production costs. Alternatives that seek to reduce the use of commercial feed can therefore both mitigate environmental impacts and reduce operational expenses. One possible strategy is incorporation of algae that crustaceans can consume with minimal biological effect into integrated multi-trophic aquaculture (IMTA) systems. Our objective was to determine whether the marine shrimp Penaeus vannamei feeds on the fresh macroalga Chaetomorpha clavata and whether the partial substitution (50 %) of this alga in its diet influences its physiology. Survival, growth, and a range of physiological processes including ingestion, defecation, metabolism, nitrogen excretion, oxidized energy substrate, hepatosomatic index, and energy budget were assessed in P. vannamei shrimp fed commercial feed (100 %, control) versus shrimp fed a combination of commercial feed and algae (50 % each). Our results showed that P. vannamei fed on C. clavata, and that there were no significant differences in mortality and growth rates (∼11 %) between shrimp fed with the two diets. The ingestion rate was higher in the group fed with macroalgae, however the defecation rate and digestibility were not affected. In both groups, no differences were detected in metabolic rates, growth, nitrogenous excretion, and egestion between shrimp fed the different diets, nor in oxidized energy substrates and the hepatosomatic index. Our results show that substituting 50 % of the feed with C. clavata represents a viable alternative to full commercial feed since it had minimal impact on the physiological functions of P. vannamei. In addition to the economic benefit of reducing the amount of feed used during culture, the use of algae also reduces contamination of effluent water, thereby improving environmental sustainability and water quality.

Influence of Mozambique Channel eddies on larval loss of two shallow-water commercial shrimp species

The shallow-water shrimp fishery is an important social and economic sector in Mozambique. However, catches of shrimps have been declining over the last decades, presumably due to poor recruitment. Climate change has been proposed as a potential cause of increased mesoscale eddy activity over the Mozambique Channel, which may have played a role in poor shrimp recruitment. Indeed, stronger eddies could transport matter, including increased numbers of shrimp larvae, from the coast to unfavourable offshore areas. In this study we used a biophysical model to investigate the influence of eddies on the dispersal of larvae of two commercial shrimp species (Penaeus indicus and Metapenaeus monoceros) from their spawning areas on the Sofala Bank. We found some 5 large events of offshore or southward transport loss (>10% loss) from the Sofala Bank caused by eddies, occurring sporadically. The northern and central Sofala Bank areas were the most affected by larvae lost offshore. Simulations revealed that temperature-induced larval mortality, associated with cold-core cyclonic eddies, could also play a role in larval loss of up to 40%, which is greater than the larval transport loss associated with the eddy circulation. However, when they survived, larvae transported offshore could travel long distances (600–1600 km in 15 days), potentially promoting connectivity with other stocks in the region.

The effect of silkworms (Bombyx mori) chitosan on rumen fermentation, methanogenesis, and microbial population in vitro.

Ruminant enteric methane (CH4) is one of the largest sources of greenhouse gases that contribute to global warming. To minimize environmental harm caused by ruminants' CH4 production, natural substances can be used to suppress it. Chitosan from crustacean sources had been known to obstruct CH4 generation in the rumen. About 18% of silkworm pupae is chitin, but little is known about the impact of silkworm pupae chitosan on rumen methanogenesis. This study investigated the efficacy of the silkworm chitosan extraction method and its impact on rumen fermentation, methanogenesis, and microbial growth in vitro. This study employed a randomized complete block design featuring five treatments and four batches for rumen incubation as the blocking factor. In this study, five treatments were implemented: Control (CO) (basal diet with no added chitosan), basal diet with 6% chitosan from the Chinese Silkworm strain 804 (CHI804), basal diet with 6% chitosan from the PS 01 Hybrid Silkworm strain (CHIPS01), basal diet with 6% chitosan from the Hybrid F1 Japanese 102 × Chinese 202 races (CHIJC02), and basal diet with 6% commercial shrimp shell chitosan as the positive control (CHICOMM). The in vitro experiments assessed digestibility, pH, total gas generation, CH4 production, ammonia nitrogen (NH3-N), and short-chain fatty acid levels, along with microbial population. Data were analyzed using a general linear model followed by Duncan's test when applicable. A significant effect on dry matter digestibility (DMD), total gas production, CH4, NH3-N, and rumen microbial populations (Methanogens, Ruminoccocus albus, Ruminoccocus flavefaciens, Selonomonas ruminantium, Butyrivibrio fibrisolvens, Streptoccocus bovis, Prevotella spp., and Bacteroides spp.) was observed (p < 0.05). The extracted chitosan (CHIJC02) used in this study exhibited a similar quality to that of commercial chitosan (CHICOMM). CHI804 treatment could reduce gas production, NH3-N production, and B. fibrisolvens population significantly (p < 0.05), while CHIJC02 could reduce CH4 production, methanogen population, acetate (C2) production, and increase propionate (C3) production significantly (p < 0.05). CHIJC02 and CHICOMM treatments could also increase the population of R. flavefaciens, S. ruminantium, and Bacteroides spp. significantly (p < 0.05). Chitosan addition significantly (p < 0.05) reduced DMD but did not impact organic matter digestibility or pH. The extracted chitosan mimics commercial chitosan in physico-chemical properties. Chitosan derived from Japanese and Chinese F1 hybrid silkworm strains demonstrated superior capacity for inhibiting CH4 generation compared to commercial chitosan. The quality and effects on methanogenesis, rumen fermentation, and rumen microbial populations can differ depending on the origin of chitosan.

Sodium content in fermented shrimp paste with varying packaging materials

Shrimp and fish paste are fermented products with high amounts of added salt. Sodium (Na+ ) ions in salt are growth factors for halophilic lactic acid bacteria (LAB), essential in shrimp paste. However, an overabundance of Na+ negatively affects the human body and may increase blood pressure and the risk of heart attacks, strokes, kidney damage, and other health issues. Commercial shrimp paste can be found in various packaging materials. The permeability of the packaging material affects air availability during fermentation, which affects LAB growth and sodium levels. This study aimed to determine the effect different packaging materials have on rebon (Acetes sp.) shrimp paste sodium levels, precisely that of teak leaf, paper, and plastic. A completely randomized design and an experimental laboratory were used for the experiments. The data were analyzed using ANOVA and Honest Significant Differences tests. The different packaging materials significantly affected (P &lt; 5%) the acidity, sodium levels, and total plate count (TPC) of LAB but did not affect the water activity or salt content. Shrimp paste consisted of 1.32±0.12% sodium when packaged in teak leaves, 1.51±0.08% in paper packaging, and 1.69±0.07% in plastic packaging. Teak leaves packaging resulted in shrimp paste with the lowest sodium content because of its many pores and high gas permeability, thus supporting the growth of microbes that use Na+ .

Arctic puzzle: Pioneering a northern shrimp (Pandalus borealis) habitat model in Disko Bay, West Greenland

Recent advancements in spatial modelling leverage remote sensing data and statistical species-environment relationships to forecast the distribution of a specific species. Our study focuses on Disko Bay in West Greenland, recognized as a significant marine biodiversity hotspot in the region. We conducted comprehensive analyses using multiple datasets spanning from 2010 to 2019, incorporating shrimp and fish surveys, commercial shrimp fishery catches, high-resolution (25 × 25 m) multibeam bathymetry and backscatter data along with a medium-resolution (200 × 200 m) bathymetric model, measured and modelled oceanographic data, and satellite chlorophyll data. Through multivariate regression analysis, we tested the significance of various physical factors (seafloor depth, sediment class, bottom water temperature, bottom water salinity, bottom current velocity, space, and time), biological factors (chlorophyll a, Greenland halibut (Reinhardtius hippoglossoides)), and anthropogenic impact (shrimp fishery; standardized catch per unit effort) on the density of northern shrimp in the area. Our results indicate a significant association between northern shrimp density, seafloor depth, and sediment class, explaining 36 % of the variation in shrimp density. Subsequently, we developed a high-resolution (optimized) spatial linear mixed–effect model to map the distribution of northern shrimp across Disko Bay, representing the first model of its kind developed for an Arctic area. The optimal habitat for northern shrimp is characterized by medium-deep waters (approximately 150–350 m), turbulent conditions, and mixed sediments, predominantly located in the northern and southern regions of Disko Bay. Notably, the northern region hosts a relatively diverse benthic community, with northern shrimp and sponges as the primary contributors of epibenthic biomass. This novel high-resolution model significantly enhances our understanding of the physical drivers and detailed spatial patterns influencing the distribution of northern shrimp in the Arctic.

The effect of liquid smoke (Cocos nucifera) in controlling acute hepatopancreatic necrosis disease in Litopenaeus vannamei

Vibrio parahaemolyticus is found in coastal environments throughout the world and is a major pathogen that causes Acute Hepatopancreatic Necrosis Disease (AHPND) with mass mortalities in Pacific whiteleg shrimp (Penaues vannamei). The extract of coconut shell liquid smoke (Cocos nucifera) was tested for antibacterial effect against AHPND in vitro. It was further evaluated for its potential efficacy in preventing AHPND in vannamei shrimp in vivo. The water in this study has been tested and positive for Vibrio parahaemolyticus. Two experimental diets were obtained by adding 0.5% and 1% liquid smoke to a commercial shrimp diet. The dietary supplementation with liquid smoke significantly enhanced shrimp growth performance during 90 days of rearing. A liquid concentration of 0.5% showed a higher growth performance (17.56 gr) than a 1% concentration (14.4 gr). Liquid smoke added to the shrimp fed partially entered the shrimp’s digestive system, and some would dissolve into the water. This water-soluble bioactive is thought to reduce the concentration of V. parahaemolyticus in waters. This was proven by the fact that no shrimp were infected with V. parahaemolyticus during the 90-day rearing.

Microbiological Analysis of Manufacturing Processes and Microbial Hazard Assessment of Quality and Safety of Commercial Salted Shrimp (Saeu-jeot)

The objective of this study was to evaluate the microbiological properties of commercially available traditional Korean salted shrimp (Saeu-jeot) and to analyze the effects of saltwater immersion and ultraviolet (UV) irradiation on the reduction of Staphylococcus aureus in Saeu-jeot. A microbiological analysis was conducted across 56 commercially available Saeu-jeot samples from the Korean, Chinese, and Vietnamese markets. The microbiological analysis revealed no presence of Escherichia coli, coliforms, or Vibrio parahaemolyticus in any commercial samples. The total viable count and S. aureus were 3.8 ± 0.4 and 0.6 ± 0.3 log CFU/g, respectively. An investigation of the procedures conducted on Saeu-jeot samples at various production stages by Hazard Analysis Critical Control Point (HACCP)-certified companies demonstrated the substantial relevance of the raw material (tiny shrimp) on S. aureus counts. In order to reduce S. aureus in Saeu-jeot, saltwater immersion and UV irradiation treatments were applied, which reduced the S. aureus counts by 1.4 log CFU/g and 0.3 log CFU/g, respectively, and S. aureus’s efficacy was limited to the food’s surface. These results suggest that a co-treatment of saltwater immersion and UV irradiation could be effective in reducing S. aureus. The maintenance of hygienic handling and cleanliness are essential in the modern manufacturing processes of Saeu-jeot.

Artemia biomass: A functional live maturation feed for Indian white shrimp, Penaeus indicus broodstock, and its culture prospective under diverse management regime

Artemia biomass production in a controlled biosecure system can be popularised in inland or coastal areas where accessibility to saltpan is limited. Against this background, four sets of experiments were executed to optimize different management regimes in Artemia biomass production, and to explore its role as a maturation diet for Indian white shrimp, Penaeus indicus. In experiment, I, Artemia biomass production was carried out in autotrophic (microalgae, TA), heterotrophic (TH), and mixotrophic (TMX) rearing systems for 18 days. Experiment II was conducted to evaluate Artemia biomass production under diverse salinity regimes (10, 15, 20, 30, 40, and 50 ppt), and in experiment III, the effect of varying stocking densities of Artemia (300, 600, 1200, and 1800 nos L−1) in production was attempted. In experiment IV, the role of adult Artemia (live, frozen, and hormone-enriched) as a maturation diet for P. indicus (36.40 ± 0.3 g) was explored, and the sex steroid profile of adult Artemia was compared with other fresh maturation feeds (polychaete, clam, and squid). At the end of Exp 1, significantly higher (P < 0.05) yields were recorded in mixotrophic (1.30 ± 0.95 kg m−3) and heterotrophic groups, (1.22 ± 0.15 kg m−3) compared with autotrophic units (0.36 ± 0.47 kg m−3). However, omega 3 fatty acids (13.92 ± 0.73%) were highest in the autotrophic system compared to TMX (11.97 ± 0.84%) and TH (8.71 ± 0.31%). In Exp II, the highest (p < 0.05) production (1.52 ± 0.13 kg m−3) was recorded at 50 ppt followed by 40 ppt (1.29 ± 0.08 kg m−3) and the lowest at 10 ppt (0.54 ± 0.01 kg m−3). The highest egg-bearing population (%) was recorded at 40 ppt (30.47 ± 3.09%) followed by 30 ppt (12.63 ± 0.82%) and 50 ppt (9.29 ± 0.80%) while none of the Artemia got matured at lower salinity treatments. The stocking density-dependent inverse relation (p < 0.01) in survival (17–67%) was registered among the treatments in Exp III with no variation (p < 0.05) in total productivity (1.26 to 1.10 kg m−3). At the end of Exp IV, 100 ± 0, 87.5 ± 7.2, and 46.6 ± 3.3% of the broodstock fed with enriched, live, and frozen Artemia had matured ovaries, respectively. A comparative analysis of sex steroids in Artemia and other fresh broodstock feeds revealed the highest (p < 0.01) 17-β-estradiol level in polychaete (998 ± 33 pg 100 mg) followed by Artemia (519 ± 28 pg 100 mg−1), clam (195 ± 29 pg 100 mg −1) and squid (61 ± 10.69 pg 100 mg−1). The study indicated mixotrophic system with 300 no L−1 density at 40 ppt can yield the optimal highest production with a better nutritional profile and higher matured population. This strongly suggests the flexibility of mixotrophic-based culture units compared with a single food source system. The presence of sex steroids in adult Artemia provides its scope as a quality fresh maturation diet and can open new vistas for its wide acceptability as SPF live maturation diet for commercial shrimp hatcheries.

Effects of culture salinity on growth and reproduction of the polychaete Dendronereis chipolini

Dendronereis chipolini is an important brackish water polychaete and has been wildly used as fattening feed for marine shrimp broodstocks. Investigation into the effects of salinity on performance of this worm species is fundamental for the development of mass culture procedure to produce feed for fattening shrimp broodstock and reduce pressure on wild catch. The study was conducted in a tank system with an area of 0.25 m2 in which the young worms (0.9±0.2 cm in length and 0.007±0.003 g in body weight) were stocked at 100 inds/tank. Four salinity treatments, including 15, 20, 25, 30 ppt, were designed with three replicates each. The worms were fed once a day at 9 am with commercial shrimp feed at a rate of 3% body weight. After 150 days of rearing, the fastest growth of worms was recorded in 20 ppt. The survival rate was also higher in 20 ppt but no significant difference was found (p&gt;0.05) between treatments. Higher absolute fecundity (103,890±17,389 and 112,740±22,328 eggs/female) was recorded at 20 and 25 ppt, respectively. The males in 20 ppt also produced a higher number of sperms. Overall, the polychaete D. chipolini reared at 20 ppt performed higher growth, survival and reproduction rates.

Construction of suspended bagasse bioflocs and evaluation of their effectiveness in shrimp (Penaeus vannamei) aquaculture systems

This experiment was carried out to improve the operability of bioflocs technology and to better the application of bagasse, a sugarcane by-product or fibrous pulp of other plant materials, in aquaculture. Firstly, a generator device for suspended-bagasse was designed, and indigenous efficient nitrogen-reducing bacteria were screened and combined. Then a suspended-bagasse bioflocs Penaeus vannamei (initial body weight of 0.78 ± 0.33 g, density of 350 shrimp/m2) culture system was constructed with bagasse and indigenous probiotics (single probiotic or composite probiotic from the previous step) as components through the generator device. The commercial shrimp culture model with commercial probiotics applied was used as a control group with three replicates in each group. The experiment lasted for 50 days. The effects of suspended-bagasse bioflocs on the water quality, shrimp growth, and immune response in the shrimp culture system were evaluated. All experimental results were analyzed using one-way variance or linear estimation. The suspended-bagasse generator could promote rapid biofilm formation on the surface of the bagasse, and the hydraulic retention parameter can be set to 12 h. Besides, three efficient nitrogen-reducing strains were screened and identified (Halomonas alkalihila AC3–2, Rugerella sp BD15–5, and Halomonas venusta BD15–8). They were non-hemolytic, sensitive to most antibiotics, and non-pathogenic to shrimp. Their combination with Bacillus megaterium BZ5 (a previously isolated probiotic) in a 1:1:1:1 ratio resulted in the highest degradation efficiencies of 97.1% and 51.4% for ammonia and nitrite nitrogen, respectively. Furthermore, application experiments in shrimp aquaculture systems showed that suspended-bagasse flocs (with single bacteria and combined bacteria) reduced ammonia and nitrite nitrogen levels and promoted nitrification in the water of the shrimp aquaculture system. This suspended bagasse floc (with combined bacteria) system reduced water usage by 37.6% per kg of shrimp produced compared to the common culture system. Moreover, the suspended-bagasse flocs (with combined bacteria) improved hepatopancreatic digestive enzyme (trypsin, lipase, and α-amylase) and serum immune-related enzyme (lysozyme and phenol-oxidase) activity. This study indicates that it is feasible to cultivate suspended-bagasse flocs in shrimp aquaculture systems using a generator device with bagasse and probiotic bacteria as components. The flocs based on bagasse and indigenous complex bacteria can effectively reduce water exchange during shrimp aquaculture and improve shrimp production. Imperfectly, the microbial community and function of the biofilm on the surface of bagasse, which is very important for the interpretation of water quality variations, was not revealed in this experiment and needs to be refined in future work. Additionally, it is also worthwhile to evaluate the effectiveness of this device in other aquatic animal culture systems.

Ingestion and adherence of microplastics by estuarine mysid shrimp

Microplastics have been reported to be present in zooplankton, yet questions persist regarding their fate and dynamics within biota. We selected the commercial mysid shrimp, Mesopodopsis orientalis, as the focal zooplankton for this study due to their crucial role in our study area, the Inner Gulf of Thailand in January 2022. We investigated the presence of microplastics in mysid bodies and fecal pellets, examining both attached microplastics on external body parts and those ingested. In addition, we conducted microplastic feeding experiments, exposing mysids to various treatments of microplastics. The results of the field investigation indicate that mysids exhibited an average of 0.12 ± 0.03 microplastic items/mysid from whole-body samples. The shape, type, and color of microplastics found in mysids were similar to those present in seawater, with blue PET microfibers being the most prevalent. Our observations on live mysids revealed that microplastics were acquired through ingestion and adherence to appendages and exoskeletons. Microplastics were observed in mysid's fecal pellets at 0.09 ± 0.03 items/mysid, while microplastics adhering to the mysid's body and appendages were observed at 0.10 ± 0.04 items/mysid. The sizes of microplastics extracted from preserved mysids ranged from 58 μm to 4669 μm, with median of 507 μm. The laboratory experiments revealed that the presence of microalgae enhanced microplastic ingestion in mysids; microplastics incubated with a cyanobacterium, Oscillatoria sp., and diatom Navicula sp. significantly increased the number of microplastic particles ingested by mysids. This study showed that microplastics can be more ingested in mysids, especially when food items are present. Microplastic fate in these animals may involve expulsion into the environment or adherence, potentially facilitating their transfer up the marine food web.

Mass variations and transfer process of shrimp farming pollutants in aquaculture drainage systems: Effects of DOM features and physicochemical properties

The expansion of aquaculture produces increasing pollutant loads, necessitating the use of drainage systems to discharge wastewater into surface water. To assess the mass variations and transfer process of aquaculture wastewater, an entire aquaculture drainage investigation lasting for 48 h was conducted, focusing on the nutrients, heavy metals, dissolved organic matter (DOM), and physicochemical properties of drainage in a commercial shrimp farm. The findings revealed that early drainage produced more heavy metals, total nitrogen (TN), dissolved organic nitrogen (DON), and feed-like proteins from aquaculture floating feed and additives, whereas late drainage produced more PO43--P and total dissolved phosphorus (TP). A few pollutants, including DON, Cu, and feed-like proteins, were effectively removed, whereas the contents of TN, dissolved inorganic nitrogen, and Zn increased in the multi-level aquaculture drainage system. Limited dilution indicated that in-stream transfer was the main process shaping pollutant concentrations within the drainage system. In the lower ditches, NO3--N, heavy metals, and feed-like proteins exhibited evident in-stream attenuation, while TN and NH4+-N underwent significant in-stream enrichment processes, especially in ditch C, with the transfer coefficient values (vf) of –1.74E-5 and –2.04E-5. This indicates that traditional aquaculture drainage systems serve as nitrogen sinks, rather than efficient nutrient purge facilitators. Notably, DOM was identified as a more influential factor in shaping the in-stream transfer process in aquaculture drainage systems, with an interpretation rate 40.79% higher than that of the physiochemical properties. Consequently, it is necessary to eliminate the obstacles posed by DOM to pollutant absorption and net zero emissions in aquaculture drainage systems in the future. Environmental implicationsNutrients, heavy metals, and dissolved organic matter are hazardous pollutants originating from high-density aquaculture. As the sole conduit to natural waters, aquaculture drainage systems have pivotal functions in receiving and purifying wastewater, in which the in-stream transfer process is affected by ambient conditions. This field study investigated the spatial variations, stage distinctions, effects of physicochemical properties, and dissolved organic matter (DOM) features. This finding suggests that the aquaculture drainage system as a nitrogen sink and DOM source. While the DOM is the key factor in shaping the in-stream transfer process, and obstacles for pollutant elimination. This study helps in understanding the fate of aquaculture pollutants and reveals the drawbacks of traditional aquaculture drainage systems.

Feasibility assessment of replacing fishmeal with Clostridium autoethanogenum protein in commercial whiteleg shrimp diets: Impacts on growth, muscle characteristics, and health

Single-cell protein (SCP) is a promising feed ingredient often referred to as bioprotein, microbial protein, or biomass. In this study, we explored the effects of replacing fishmeal with a novel single-cell protein, Clostridium autoethanogenum protein (CAP), on the growth performance, immunological responses, muscle characteristics, intestinal and hepatopancreas histology, survival rate and bacterial resistance in whiteleg shrimp (Litopenaeus vannamei). The shrimp postlarvae (PL), sourced from Thailand and confirmed free of various pathogens, were acclimated and reared in a controlled water recirculation system. Four replicated aquariums, each containing twenty shrimps with an average weight of approximately 3.25 g, were assigned to each experimental group (N = 4). Experimental diets, designed based on a commercially relevant feed formula, were provided four times per day over an 8-week period. The experimental diets included a control diet and three diets with different levels of fishmeal replaced by CAP at 30% (4.5SCP group), 66.7% (9SCP group), and 100% (20SCP group). The results revealed a significant reduction in the growth performance of shrimp in the 20SCP group, with a lower final weight (16.77 ± 0.76 g), weight gain (415.9 ± 24.7%), specific growth rate (2.93 ± 0.08%), and average daily growth (0.24 ± 0.02 g/day) compared to the control group (18.96 ± 0.27 g, 484.8 ± 13.3%, 3.15 ± 0.04%, 0.28 ± 0.01 g/day, respectively). In contrast, shrimp in the 4.5SCP and 9SCP groups, however, did not exhibit such adverse effects and had growth parameters comparable to the control group. Replacing fishmeal with SCP at 100% (20SCP group) significantly increased the muscle hardness but decreased the muscle springiness, chewiness and cohesiveness of whiteleg shrimp. Histological analysis of the midgut revealed that the 20SCP group exhibited a thinner wall thickness (51.9 ± 17.4 µm), wider villi width (80.86 ± 15.87 µm), and longer villi height (85.24 ± 17.41 µm) compared to the control group (66.9 ± 19.1 µm, 50.35 ± 11.47 µm, 52.92 ± 23.58 µm, respectively). Compared to the control group, immune parameters such as phagocytic rate, respiratory burst activity, and total hemocyte count, but not phenoloxidase activity, were often lower in shrimps that ingested higher levels of SCP. The transcript level of most immune and physiologically related genes analyzed was not significantly modulated in the hemocyte, hepatopancreas, foregut and midgut on days 28 and 56. The findings suggest that replacing fishmeal with up to 60% CAP in shrimp diets could be a feasible option, providing a novel protein source for sustainable aquaculture practices. Further research is necessary to elucidate the precise mechanisms underlying these effects and optimize CAP inclusion levels for enhanced shrimp performance and health.