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The acute respiratory disease COVID-19, caused by the novel Coronavirus SARS-CoV-2, is a worldwide pandemic affecting millions of people. The methodology that organizations who provide home health and personal home care services are using to respond to this pandemic has not yet been characterized. In this report, we describe our approach to comprehensive outbreak suppression and report an initial case series of COVID-19 positive patients receiving home-based services. We implemented enhanced infection control procedures across our affiliates, and we communicated these protocols to our offices using multi-faceted methods. Using custom built software applications enabling us to track patient and employee cases and exposures, we leveraged current public health recommendations to identify cases and to suppress transmission. In the 100-day period between January 20, 2020 and April 30, 2020, our affiliates provided services to 67 COVID-19 positive patients (

Black solider fly larvae (BSFL) and their oils (BSFLO) are receiving increasing attention as sustainable ingredients in fish feeds, but mostly as replacements to marine sources. There were two aims to this study; in exp. 1, soybean meal (SBM)-based diets were formulated to contain BSFL as supplements at 0 (SBM), 8 (SBM + BSFLlow) or 16% (SBM + BSFLhigh) with a control diet being fishmeal-based (FM). In exp. 2, diets included only fish oil (FO), soybean oil (SBO), BSFLO or BSFLO + bile acid (BA), and all lipid sources were added at 16%. Both experiments were run at the same time and fed to rainbow trout (32 g) with each treatment being triplicated. After 10 weeks the fish were sampled for liver and distal intestine histology, expression of genes responsible for inflammation in the intestine and kidneys, and serum peroxidase and lysozyme activities. In exp. 1, supplementations of BSFL effectively prevented SBM-induced intestinal enteritis, down-regulated intestinal prostaglandin and interferon regulatory factor 1 (IRF-1), while the SBM + BSFLhigh diet significantly increased serum lysozyme activity. In exp. 2, BSFLO caused no histomorphological change to the liver or intestine, but kidney interluekin-8, tumor necrosis factor and IRF-1 were significantly upregulated along with significantly higher serum peroxidase activity. The inclusion of BA in the BSFLO diets significantly upregulated intestinal prostaglandin gene expression. Overall, BSFL supplementations of 8 or 16% prevented SBM-induced intestinal enteritis based on histological observations, which was supported by a down-regulation in pro-inflammatory genes and enhanced innate immunity. Meanwhile, the use of BSFLO showed some immunological benefits. Therefore, these sustainable resources are recommended in the diets of rainbow trout, especially when using elevated levels of plant-based proteins.

Residents of congregate care settings have been severely impacted by the current Coronavirus disease 2019 (COVID-19) pandemic. In this report, we describe the methods our home-based primary care practice has developed to mitigate the spread of COVID-19 in assisted living facilities (ALFs) and we present an initial evaluation of this innovation. Shortly after the first COVID-19 case was reported in the United States, our organization assembled an outbreak committee, designed to support the 1794 ALF residents and the 101 communities in which they reside. The committee led the development and deployment of a comprehensive COVID-19 prevention and suppression strategy. The average age of the cohort was 83 ± 11 years, and 74% were female. Seven individuals (0.4% of census) tested positive for SARS-CoV-2. The positive individuals were located in 3 ALFs, representing 3% of our total number of ALFs. There has been 1 death. Home-based primary care-led outbreak mitigation may be an enabler to suppress COVID-19 in ALFs.

Plant-based proteins are increasingly being used in aquafeeds, but one of the limitations is taurine deficiency that can be especially detrimental for carnivorous fish. In this study, taurine supplementation in high plant protein diets (low fish meal, 15%) was investigated on the growth performance and fillet organoleptic characteristics of European seabass (Dicentrarchus labrax), juveniles (78 ± 0.4 g). Five diets were formulated to contain 0 (C−), 5 (T5), 10 (T10) or 20 (T20) added taurine (g/kg), while a control diet (C+) included two-fold higher amount of fishmeal (30%) with no taurine supplementation. Seabass fed the T20 or C+ diet showed similar growth, which was significantly higher compared to those in the C-treatment. Histological examination of the muscle, liver and intestine were similar among treatments. No effect on spoilage bacterial growth or production of total volatile basic nitrogen was observed. Taurine supplementation significantly reduced fillet drip loss, while the fillets of European seabass fed the T10 and T20 diets showed significant higher and lower hardness and adhesiveness values, respectively. Moreover, fillet chewiness was also found to be significantly higher in fish fed the T20 diet compared to C+ and C− diets. Overall, it seems that high dietary taurine supplementation acted as a growth promoter and concurrently improved significantly the postharvest quality characteristics of seabass, which may be attributed to its role in maintaining cell membrane integrity and permeability.

This study was conducted to investigate the effects of dietary probiotic quorum sensing degrader Bacillus cereus on the growth performance, intestinal short‐chain fatty acid levels, antioxidant status and histopathological response of Macrobrachium rosenbergii against Aeromonas hydrophila. M. rosenbergii juveniles were fed with 10⁴ cfu/g probiotic B. cereus, while the control group was fed without B. cereus. After 28 days of feeding, growth performance was significantly higher (p 0.05) were observed for acetic acid or butyric acid levels. Dietary B. cereus supplementation significantly (p

African catfish (Clarias gariepinus) and lemon fin barb hybrid (LFBH) (Hypsibarbus wetmorei ♂ × Barbodes gonionotus ♀) were cultured in either a biofloc technology (BFT) system or an individual recirculating aquaculture system (RAS) and their survival, growth, feeding efficiencies and biochemical composition were then compared after 8 weeks. LFBH and African catfish were chosen based on their different feeding habits. In the BFT treatments, glycerol was added to create a carbon to nitrogen ratio of 15, while the RAS system consisted of a fine mesh mechanical and biological filter. Each of the four treatments was triplicated, with each replicate consisting of 20 African catfish (0.98 ± 0.05 g) or LFBH (1.77 ± 0.02 g). Water quality and biofloc formation were examined weekly while the biofloc proximate composition was measured in weeks 5 and 8. During weeks 6, 7 and 8 the total viable bacterial colony forming units (CFU) were quantified. Regardless of species, biofloc formation was similar but the crude protein, lipid and ash significantly decreased from week 5 to week 8. However, biofloc crude protein and ash were significantly higher in the LFBH treatment. Total viable CFU were significantly higher (P

Cholesterol is a major sterol in crustaceans that occurs in all cells and in the hemolymph, either in free form or combined with fatty acids. Unlike vertebrates, shrimps and other crustaceans are i...

An 8-week study was conducted on the use of native tapioca starch (TS) or pre-gelatinized tapioca starch (PGTS), with or without the inclusion of isomaltooligosaccharides (IMO) at 0.5% on the growth, feeding efficiencies, muscle and plasma biochemical composition, intestinal short chain fatty acids (SCFA), differential cell counts, phagocytic ability/capacity, and liver glycogen content in African catfish, Clarias gariepinus. Each treatment was triplicated with each replicate consisting of 10 fish (initial weight of 6.2 ± 0.3 g). The bulk density (BD), pellet durability index (PDI), water stability (WS), water absorption index (WAI), water solubility index (WSI), and protein solubility (PS) were measured in all experimental diets. The results showed no significant (p > 0.05) growth differences among the treatments, but feed intake was significantly lowest (p

A 9-week study was conducted to compare dietary corn starch (CS) or tapioca starch (TS), with or without being pre-gelatinized (PG), on the growth, feeding efficiencies, plasma and muscle biochemistry, intestinal short chain fatty acids (SCFA), and liver glycogen of triplicate groups of 20 red hybrid tilapia (Orecohromis sp.). Various pellet characteristics were evaluated, along with their surface and cross sectional microstructure. The PG diets had significantly higher water stability, bulk density, and protein solubility, along with a smoother surface. Tilapia fed the TS diet had lower growth than had all other tilapia, but were significantly improved when diet was pre-gelatinized. In the PG treatments, intestinal SCFA significantly decreased while plasma glucose, cholesterol and triglycerides, as well as liver glycogen, significantly increased. Fish fed the CS diet had significantly more long chain polyunsaturated fatty acid than had those fed by other treatments. Pre-gelatinization may improve fish productivity and offer greater flexibility during aquafeed production.

The effects of increasing glycerol loading rates to create carbon to nitrogen (C/N) ratios of 0 (control), 10, 15 or 20 were investigated on the biofloc formation, biochemical composition and water quality, as well as the growth performance, feeding efficiencies, biochemical composition, trypsin/chymotrypsin enzyme activities, and liver glycogen of African catfish Clarias gariepinus after 6 weeks. Each treatment was triplicated and each replicate consisted of 25 juveniles (11.77 ± 0.01 g; mean ± SE). After six weeks, all fish were measured for growth, ten fish/replicate were used for additional analysis while ten fish/replicate were later challenged with the bacterial pathogen, Aeromonas hydrophila . Biofloc volume was significantly higher ( P P P P P > 0.05), but the input-output ratio significantly increased ( P P P P A. hydrophila , survival was significantly higher ( P C. gariepinus as well as their resistance to A. hydrophila .

The feasibility of carob seed germ meal (CSGM) as a soybean meal (SBM) replacement in the diet of red tilapia hybrid was evaluated in an 8-week feeding trial. Five isonitrogenous and isocaloric diets with increasing CSGM (0, 10, 20, 30 and 40%), at the expense of SBM, were fed to triplicated groups of tilapia fingerlings. Their growth, feeding efficiency, whole body proximate composition, selected plasma biochemical parameters, and liver and gut histopathology were assessed. The survival and growth of red tilapia were unaffected by the dietary CSGM inclusion up to 30%. Growth and feeding efficiencies were significantly reduced at 40% CSGM inclusion. Hematocrit and body crude lipid were significantly lower (p

A 6-week experiment was performed to compare different carbon sources, i.e. sucrose, glycerol and rice bran, to a nitrogen ratio of 15:1 in a biofloc-based African catfish Clarias gariepinus culture system. Catfish survival, growth, whole-body proximate composition, body indices, liver histopathology and glycogen content were measured. Each treatment was triplicated in glass aquaria with each replicate containing 50 fish (500 fish/m3) with an initial weight ± SD of 5.06 ± 0.05 g. Glycerol significantly increased total biofloc production, and both the sucrose and glycerol treatments generally had lower nitrogenous levels, compared to the control. These levels spiked at week 2 in the rice bran treatment, leading to significantly lower survival compared to all other treatments. At both weeks 3 and 6, liver histopathology of fish in the rice bran treatment revealed substantial vacuolation and less glycogen while the highest was in fish from the glycerol treatment. Fish growth was unaffected among the treatments, but survival was highest in the glycerol treatment. Rice bran appears unsuitable for C. gariepinus, likely due to being a slower-releasing carbon source. Instead, glycerol is recommended based on significantly higher biofloc production and subsequently improved water quality and survival of C. gariepinus during their nursery culture.

Aqueous and methanol extracts of lemon Citrus limon peel, Euphorbia hirta (aerial parts), and fenugreek Trigonella foenum-graecum seeds were tested for their in vitro antimicrobial activities against the bacterium Aeromonas hydrophila. A swab paper disk method showed that the methanol extract of E. hirta (EHE) had the largest inhibition zone and the lowest minimal inhibitory concentration compared to all other herbal extracts. Based on these results, EHE was included in the diets of Sharptooth Catfish Clarias gariepinus at 0 (control), 2, 5, or 7 g/kg of diet (experiment 1). Each treatment was conducted in triplicate, with 30 fish (mean weight ± SE = 9.4 ± 0.4 g) in each replicate. After 30 d, the growth, feed intake, hepatosomatic index (HSI), and plasma biochemical parameters were measured. With a separate batch of Sharptooth Catfish, the efficacy of the EHE diets in conferring fish resistance to A. hydrophila over 30 d was compared to that of a diet containing oxytetracycline (OTC; experiment 2). Six treatments were conducted in triplicate groups of 30 fish (mean weight ± SE = 9.0 ± 0.3 g); the Control fish were fed the control diet and were not injected with A. hydrophila, while the Control-AH and OTC-AH groups were infected with A. hydrophila and were fed either the control diet or the diet containing OTC at 1 g/199 g. The other three treatments included fish that were injected with A. hydrophila but fed diets with increasing EHE at 2, 5, or 7 g/kg. Experiment 1 showed no change to growth, feeding efficiency, HSI, or plasma biochemical parameters. In experiment 2, however, fish that were fed dietary EHE at 5 g/kg had significantly lower mortality than the Control-AH group, with further resistance observed for fish fed EHE at 7 g/kg. Dietary OTC was more effective than EHE as a prophylactic to A. hydrophila infection in Sharptooth Catfish. Nevertheless, EHE can potentially be a valuable dietary supplement to improve the resistance of Sharptooth Catfish to A. hydrophila infection. Received May 3, 2017; accepted August 24, 2017.

The use of short-chain organic acids in the diets of aquacultured animals as a prophylactic to bacterial pathogens is receiving increasing research and commercial interest. After giant freshwater prawns, Macrobrachium rosenbergii, were fed diets supplemented with formic (FA), citric (CA), lactic (LA), propionic acid (PA), an organic acid blend (OAB) at 1% or a control diet (no additives) for 6 weeks, the prawns were subjected to Vibrio harveyi challenge for 2 weeks. From all remaining prawns, the hepatopancreatic histopathology was examined. Results showed that the survival of prawns to V. harveyi challenge was significantly higher (P

Jatropha seed cake (JSC) is an excellent source of protein but does contain some antinutritional factors (ANF) that can act as toxins and thus negatively affect the growth and health status of fish. While this can limit the use of JSC, detoxified Jatropha protein isolate (DJPI) may be a better option. An 8-week study was performed to evaluate dietary DJPI to common carp Cyprinus carpio. Five iso-nitrogenous diets (crude protein of 38%) were formulated that consisted of a C ontrol (fish meal (FM) based protein), J 50 or J 75 (50 and 75% of FM protein replaced by DJPI), and S 50 or S 75 (50 and 75% of FM protein replaced by soy protein isolate, SPI) and fed to triplicate groups of 75 carp fingerlings (75; av. wt. ± SD; 11.4 ± 0.25 g). The growth, feeding efficiencies, digestibility, plasma biochemistry, and intestinal enzymes were measured. Results showed that growth performance of fish fed the S 75- or DJPI-based diets were not significantly different from those fed the C ontrol diet, while carp fed the S 50 had significantly better growth than the J 75 diet. Fish fed the J 75 diet had significantly lower protein and lipid digestibility as well as significantly lower intestinal amylase and protease activities than all other groups. However, all plant protein-based diets led to significantly higher crude protein, crude lipid, and gross energy in the body of common carp compared to the control treatment. Plasma cholesterol and creatinine significantly decreased in the plant protein fed groups, although plasma triglyceride as well as the red blood cells count, hematocrit, albumin, globulin, total plasma protein, and lysozyme activity were higher in plant protein fed groups compared to FM fed group. White blood cells, hemoglobulin concentration, alkaline phosphatase and alanine transaminase activities, and glucose level in blood did not differ significantly among treatments. The results suggest that the DJPI is non-toxic to carp and can be used to replace FM in the diets of common carp up to 75%, but further research to potentially reduce some inherent ANF within this protein source, such as non-starch polysaccharides, may improve nutrient utilization.

A feeding trial was performed to assess the effects of dietary Medlar (Mespilus germanica) leaf extract (MLE) on the growth performance, skin mucus non-specific immune parameters as well as mRNA levels of immune and antioxidant related genes in the skin of common carp (Cyprinus carpio) fingerlings. Fish were fed diets supplemented with graded levels (0, 0.25, 0.50, and 1.00%) of MLE for 49 days. The results revealed an improvement to the growth performance and feed conversion ratio in MLE fed carps (P 0.05), regardless of the inclusion level. The immunoglobulin levels and interleukin 8 levels in the skin mucous and skin, respectively, revealed significant increment in fish fed 1% MLE (P 0.05) in comparison with the other MLE treatments and control group. Also, feeding on 0.25% and 0.50% MLE remarkably increased skin mucus lysozyme activity (P 0.05). However, there were no significant difference between MLE treated groups and control (P 0.05) in case protease activity in the skin mucous or tumor necrosis factor alpha and interleukin 1 beta gene expression in the skin of carps (P 0.05). The expression of genes encoding glutathione reductase and glutathione S-transferase alpha were remarkably increased in MLE fed carps compared to the control group (P 0.05) while carp fed 0.50% or 1.00% MLE had significantly increased glutathione peroxidase expression in their skin (P 0.05). The present results revealed the potentially beneficial effects of MLE on the mucosal immune system and growth performance in common carp fingerlings.

Five‐week‐old silver barb, Barbodes gonionotus, fry (initial length = 10 mm) were subjected to different salinities of 0, 3, 6 or 9 ppt for 17 days, to then assess their survival and growth. Whole body histological sections were stained with Periodic‐acid Schiff (PAS). Groups of 15 fish were triplicated in each treatment with an ambient temperature (26–28°C). Results showed that growth and condition factor significantly decreased and increased (p .05), between 0 and 6 ppt (at 98% and 87%, respectively), the decrease was significant at 9 ppt (22%). In addition, the fry at 9 ppt had fewer gill mucous cells as well as reduced PAS positive staining intensity within the liver and intestine. This suggests energy was becoming exhausted, leading to mortalities and lower growth. Silver barb early fry were relatively sensitive to elevated salinity, which was likely due to their young age, but short‐term exposure to 3–6 ppt can be used to decrease potential freshwater diseases in the early nursery culture.

The feasibility of dietary soybean meal (SBM) replacement for fishmeal was evaluated to the swimming crab Portunus pelagicus juveniles over six consecutive molts by measuring their growth, development, hemolymph cholesterol, triglycerides, phosphate, whole-body crude protein and cholesterol as well as hepatopancreatic trypsin activity, histopathology and glycogen reserves. A total of six isonitrogenous, isolipidic and isoenergetic diets were formulated with SBM replacing fishmeal at 0 (control), 20, 40, 60, 80 or 100% of total dietary protein. Each treatment consisted of 30 replicate crabs starting from the first juvenile stage and after the crabs molted to the seventh stage, three-day post molt crabs were sampled. Results showed that crabs fed the 20% SBM diet had the best growth, which was significantly higher than the control diet (0% SBM). Growth became significantly lower in the 60% dietary SBM treatment and above, while hemolymph cholesterol, triglycerides and phosphate significantly decreased with increasing dietary SBM. The whole-body moisture, crude protein and cholesterol were unaffected by dietary SBM. Meanwhile, hepatopancreatic trypsin activity significantly decreased in the 20 to 60% SBM treatments, with a further significant decrease in the 80 and 100% SBM treatments. Hepatopancreatic damage, significantly fewer epithelial cells and glycogen reserves occurred at 60% SBM and above. Results indicate that dietary SBM can replace up to 40% of fishmeal in the diets of P. pelagicus juveniles without reducing their growth or hepatopancreatic condition.

Improved sustainable aquaculture can be achieved through biofloc technology (BFT) by reducing feed input and water use. Although BFT is considered a viable culture strategy to various crustaceans, including Macrobrachium rosenbergii, the influence of salinity has not received much attention. The aim of this study was to investigate the effects of increasing salinities of BF0, BF5, BF10, and BF15 PSU on M. rosenbergii post larval (PL) growth performance and proximate composition in a biofloc system as well as water quality, total bacteria and Vibrio spp. and zooplankton abundance/composition. A carbon: nitrogen ratio was maintained at 10 by maize starch additions. Each tank contained 500 prawns (42.5 ± 5.6 mg) in triplicate. Growth was similar (p > 0.05) in BF0, BF10 and BF15, but was significantly lower in BF5. The best FCR was observed in BF15 and BF10. PL survival was significantly (p 0.05); however, at weeks 3 and 4, ammonia-N was higher in BF0 (p

Goldfish (Carassius auratus) juveniles were exposed to virgin polyvinyl chloride microplastics (PVC-MPs) in triplicate at 0, 0.1 or 0.5 mg/L for four days. Afterwards, the histopathology of the gills, liver and intestines were examined, along with various antioxidant enzymes and indicators of oxidative damage (malondialdehyde (MDA) and hydrogen peroxide (H2O2)), in the brain, liver and gills. In addition, we also studied the expression of hepatic insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 1 (IGFBP-1) and growth hormone (GH) receptor, while cortisol receptor (CR) and cytochrome P450 1A (CYP1A) gene expression were assayed in both the liver and gills. Histological analysis revealed PVC-MPs in the intestines at 0.1 and 0.5 mg/L, along with substantially shorter villi. The gills appeared undamaged by PVC-MPs exposure and had limited or no effect to antioxidant activity, Na+/K+-ATPase and H+-ATPase activity or plasma ion levels, but there was a prominent upsurge of the detoxification enzymes glutatione S-transferase (GST) activity and CYP1A expression. Livers showed inflammation and some occurrences of hemorrhaging and necrosis at 0.5 mg/L. While the brain showed some evidence of oxidative damage, the liver was the most susceptible to oxidative damage, based on increased MDA, H2O2 and various antioxidant enzymes. Hepatic expression of IGFBP-1 and GH receptor were significantly downregulated at 0.5 mg/L while CR was upregulated. Results indicate that exposure to environmentally relevant PVC-MP can cause oxidative damage in the brain and liver, adverse histomorphological changes to the intestine and liver and alter the gene expression in goldfish.

Organic acids are receiving increasing attention as a potential means to improve the growth as well as nutrient utilization of aquatic animals. A 20-day experiment was conducted to compare the effects of different dietary organic acid salts that included sodium acetate, sodium citrate, sodium butyrate, or sodium propionate at 2%, on the survival, growth, and hepatopancreatic histopathology of blue swimmer crab Portunus pelagicus early juveniles. All diets were isonitrogenous and were provided to apparent satiation twice daily. Crabs were kept individually within plastic containers, and there were 45 replicate crabs for each treatment. Results showed that, by the third molt, all the tested dietary organic acids significantly (P < 0.05) accelerated the molting (7.16–8.65 days) of the crabs compared with those in the control treatment (10.03 days). The specific growth rate (SGR) for width and length as well as the final dry weights were significantly higher (P < 0.05) in all the organic acid treatments, while SGR for weight was significantly higher (P < 0.05) in the sodium acetate and sodium propionate treatments, compared with the control. Hepatopancreatic histopathology revealed no structural differences in all treatments or staining intensity for glycogen. To our knowledge, this is the first reported study showing improvements to the survival and growth of crabs fed with inclusions of dietary organic acids.

Among organic acids, citric acid and their salts are currently the most studied as a supplement in aquafeeds to potentially improve growth and nutrient utilization in fish. The results have been generally beneficial but no studies have been performed on tilapia. A 50 day experiment was conducted on the effects of dietary sodium citrate at 0, 1, 2 and 4% on the growth, feeding efficiency, body indices, muscle proximate composition, muscle lipid peroxidation, some plasma and blood parameters, intestinal short chain fatty acids (SCFA), and liver histopathology of red hybrid tilapia (Oreochromis sp.). Triplicate groups of 60 tilapia fingerlings (initial weight of 1.86 ± 0.01) were in each treatment. Results showed that, while not significant, increasing dietary sodium citrate reduced tilapia growth (p > 0.05). However, muscle crude protein (r2 = 0.931), lipid (r2 = 0.962), and ash (r2 = 0.834) significantly decreased at increasing dietary sodium citrate levels (p Statement of relevance Sodium citrate reduced growth but may increase shelf-life.

A 10-day experiment was performed to examine different mono, binary and ternary dietary combinations on survival and growth of D-shaped and umbone black-lip pearl oyster, Pinctada margaritifera, larvae. The three tropical microalgae species were the flagellate Isochrysis galbana clone T. Iso (CS-177) and diatoms Chaetoceros calcitrans (CS-178) and Chaetoceros muelleri (CS-176) which were fed to D-shaped and umbone larvae at a density of 7000 and 14 000 cells mL−1, respectively. A second experiment was performed to investigate the feasibility of replacing T. Iso with a lipid emulsion for both D-shaped and umbone larvae for 10 and 12 days, respectively. The treatments included only T. Iso, unfed and lipid emulsion to substitute T. Iso at levels of 10% (LIP10), 30% (LIP30) and 100% (LIP100). In the first experiment, results showed that a monospecific diet of T. Iso led to significantly higher (P 0.05) from the unfed treatment. For D-shaped larvae, no significant growth difference was detected (P > 0.05) between the T. Iso and LIP10 fed treatments while for umbone larvae, the T. Iso, LIP10 and LIP30 were not significantly different (P > 005). These results indicate that microalgae combinations appear more necessary for later staged P. margaritifera larvae. In addition, the use of a lipid emulsion appeared to provide some nutrition to the larvae, although more research should be conducted to improve the use of such replacements.

The fatty acid composition, moisture, and total lipid of the eggs from the swimming crab, Portunus pelagicus, at three different embryonic stages (within 24 h, during the eye placode stage and the final heart beat stage), were measured. Results showed that the moisture and lipid content significantly increased and decreased (p

Water hardness varies regionally and optimal levels for fish are often species specific. It is generally assumed that largemouth bass, Micropterus salmoides, require elevated water hardness, but this has not yet been investigated. In this two-part study, M. salmoides juveniles were subjected to 100, 200, 400 and 600 mg/l CaCO3 (by CaCl2 additions) and the survival, growth, ammonia-N excretion/oxygen consumption rates, biochemical composition and ion-regulatory enzymes were measured after one month. Afterwards, fish were subjected to a sudden salinity shock test (SSST) at 10 ppt. In experiment 2, M. salmoides juveniles were subjected to 50 or 400 mg/l CaCO3 for one month and measured for the above-mentioned parameters. In experiments 1 and 2, both feed intake and feed conversion ratio (FCR) significantly decreased at 400 mg/l CaCO3, compared to 50 or 100 mg/l CaCO3, however, hardness had no significant effect on survival or growth. There was no significant effect to gill Na+/K+-ATPase or H+-ATPase activities; however, survival to SSST was significantly less at 50 or 100 mg/l than the other treatments. At 400 mg/l CaCO3, ammonia-N excretion/oxygen consumption rates were significantly less compared at 50 mg/l CaCO3, indicating greater energy expenditure at lower water hardness. These results demonstrate that while high water hardness substantially improves stress resistance in M. salmoides juveniles, they do not require high water hardness for optimal growth.

Biofloc technology (BFT) relies on adding organic carbon, often in the form of sugars or starches, to encourage heterotrophic bacteria that convert otherwise toxic ammonia/nitrite into potentially consumable biomass known as ‘bioflocs’. The subsequently higher turbidity may be inappropriate for more carnivorous fish, but research in this area is limited. In this study, largemouth bass Micropterus salmoides juveniles (7.27 g) were cultured in either a clear-water system (CWS) or BFT system. Each week, a sub-sample of M. salmoides was measured for length, weight, hepatosomatic index (HSI) and hemoglobin. After 4 weeks, M. salmoides were measured for productivity, muscle/liver biochemical composition, gill Na+/K+-ATPase/H+-ATPase activities, plasma cortisol, as well as the histomorphology of the gills and liver. Within 7 days, Bacillus spp., Acinetobacter spp. and Enterobacter spp. were detcted in the BFT tanks, but were replaced with Planococcus spp. by week 4. Despite consistently lower nitrogenous waste levels in BFT, growth became significantly reduced, which was likely due to elevated circulating cortisol depressing feed intake. Livers from fish in BFT showed some local inflammation while nearly all the secondary gill lamellae on the gills were shorter. This latter finding may have contributed to significantly elevated and depressed hemoglobin level and gill Na+/K+-ATPase activity in BFT, respectively, after 4 weeks. Although survival was similar between treatments, long-term culture of M. salmoides with BFT is not advisable likely due to excessive suspended solids accumulation, including mucus. However, BFT may be a short-term strategy to reduce excessive nitrogenous waste levels in times of limited access to water.

Various strategies exist to control noxious cyanobacterial populations, although the application of a newly developed granular compound (sodium carbonate peroxyhydrate 'SCP', trade name 'PAR (R) 27' algaecide) containing hydrogen peroxide (H2O2) as the active ingredient, has been recently proven as an effective and eco-friendly treatment. However, in aquaculture settings the application of SCP to treat cynobacterial blooms may affect non-targeted biota, such as fish due to H2O2 being known to elicit toxic oxidative stress. Consequently, a better understanding of the side effects as a function of dosing concentrations would help to improve treatment efficacy and fish welfare. Thus, the aim of the current study is to assess the potential risks of SCP to largemouth bass (Micropterus salmoides), a high priced fish in the U.S. To this end, fish were exposed to two recommended doses of SCP corresponding to either 2.5 or 4.0 mg/L H2O2 for 6 days, with a control group in parallel. After 6 days, the effect of SCP exposure on oxidative stress, histopathological changes and anti-oxidant potential in the brain, liver, gills and muscle were investigated. Results show that exposure to 4.0 mg/L H2O2-SCP incited oxidative damage, evidenced by an over-accumulation of H2O2 and malondialdehyde (MDA) in the brain and liver, which were accompanied by an increment in xanthine oxidase activity. Unlike 4.0 mg/L H2O2, these oxidative stress biomarkers in the brain and liver tissue of 2.5 mg/L H2O2-SCP exposed fish were restrained within control levels and concomitant with an increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione-s-transferase (GST) activity. In contrast, many of these anti-oxidants sentinels in the 4.0 mg/L H2O2 exposed fish were either unaffected or significantly inhibited, which resulted in over-accumulation of H2O2 and MDA. In addition, a series of histopathological alterations were observed, and the most severe brain injuries and liver inflammation were recorded in 4.0 mg/L H2O2-SCP exposed fish. Based on oxidative parameters, both SCP doses resulted in a relatively mild oxidative stress in gills but no effect in muscle, probably explaining the modest anti-oxidative responses in the former and almost complete lack of anti-oxidative responses in the latter. Overall, our findings suggests that the application of SCP at 4.0 mg/L H2O2 to control cyanobacterial blooms in aquaculture settings can possess potential risks to the farmed fish.

Phytic acid is a compound found in plants that stores phosphorus (P) in a highly stable form and also binds with various nutrients including minerals, proteins, starches, and lipids. Many plant-based ingredients commonly added in the diets of terrestrial and aquatic animal feeds are high in phytic acid. For nonruminant animals, phytic acid is largely indigestible and therefore can reduce nutrient utilization leading to reduced growth and bone mineralization as well as excessive phytic-P discharge to the environment. Some secondary effects to the host animal can include suppressing appetite, digestive enzymes, or irritating the gut. The enzyme phytase degrades phytic acid and can be used as an effective pretreatment to ingredients or directly included as a safe supplement in animal feeds to reduce these harmful effects. Generally, phytase greatly improves mineral digestibility in animals, but its effects as a growth promoter are highly variable. The efficiency of this enzyme depends on pH, presence of P and calcium (Ca), phytase type/level as well as interactions with other ingredients or nonphytase enzymes. To optimize phytase activity, diets should be deficient in P and Ca, while dietary acidifiers such as some organic acids may exert synergistic effects to digestibility and/or growth. Moreover, nonphytase enzymes, particularly carbohydrate-degrading enzymes, may allow more sites for phytase activity in plant-based ingredients. These interactions are receiving increasing attention, with indications that the gastrointestinal health of animals can also be improved. Indeed, rather than phytase being viewed as a means to substitute for additional P supplementations, and thus being more environmentally friendly, the inclusion of phytase with other natural supplements has the potential to act as a prophylactic to disease.

Much of the research into improving the nutritive values of ingredients has mainly focused on plant proteins by decreasing various antinutritional factors (ANFs) inherent in these ingredients. While the use of enzymes can successfully reduce ANFs, many plant proteins are in high demand in the food-producing industries, particularly soybean meal. Therefore, new or alternative feedstuffs to terrestrial plant protein sources are increasingly being investigated, such as feather meal, algae meals, and insect meals. Each of these ingredients has a high potential for use in animal and fish feeds, but they also contain unique compounds that can also potentially act as ANFs. Reducing these specific compounds can be accomplished with enzymes, whilst simultaneously enhancing their nutritive value, which will be part of the focus of this chapter. Algae constitute a renewable resource used by the food industry, as feed for animals, to produce phycocolloids, as cosmetic ingredients, and for pharmaceutical applications as well as for biomaterials. Also, on the one hand they have suitable potential for decontamination. However, on the other hand their uncontrolled proliferation due to excessive nutrients environmental load is a strong concern related to natural conditions preservation. The Earth’s available stocks of lignocellulosic biomass are tremendous and distributed all around the world. Thus, the sustainability of the valorization of cellulose by cellulases seems clear. More economical feeding can most probably be obtained by improving pretreatment and enzymatic hydrolysis of cellulose. Furthermore, an application into human nutrition may be also possible. Laccases are already utilized in several industries as well as in bioremediations tools. Their potential in valorization of lignocellulose from nonedible plant biomass for nutrition use should be evaluated.

Silver barb Barbodes gonionotus fry were exposed to polyvinyl chloride (PVC) fragments at increasing concentrations of 0.2, 0.5 and 1.0 mg/L for 96 h, following which whole body histological evaluation and analysis of the digestive enzymes trypsin and chymotrypsin were performed. Whole body trypsin and chymotrypsin activities increased significantly in fish exposed to 0.5 and 1.0 mg/L PVC as compared those exposed to zero or 0.2 mg/L PVC. In fish exposed to all tested concentrations, PVCs were observed in both the proximal and distal intestine, and fish exposed to 0.5-1.0 and 1.0 mg/L PVC, respectively, and these particles were associated with localized thickening of the mucosal epithelium. No tissue damage was evident in any other internal organs or gills. This lack of damage may be attributed to the absence of contaminants associated with the PVC fragments and their relatively smooth surface. The increased whole body trypsin and chymotrypsin activities may indicate an attempt to enhance digestion to compensate for epithelial thickening of the intestine and/or to digest the plastics.

A 20-week feeding trial was conducted to measure growth, nutrient utilization and faecal/gut bacterial counts in triplicate groups of red hybrid tilapia, Oreochromis sp., when fed diets supplemented with 0.5% organic acids blend (OAB), 1.0% OAB, 0.5% oxytetracycline (OTC) or a control diet (no additives). At the end of the feeding trial, tilapia were challenged with Streptococcus agalactiae for 22 days. Fish fed the OTC diet had significantly higher (P 0.05). Phosphorus, dry matter and ash digestibility were significantly higher in the 1.0% OAB diet than the control diet. Fish fed the OAB diets had significantly lower colony-forming units of adherent gut bacteria compared to the control or OTC treatments while those fed the 1.0% OAB diet had the lowest total faecal bacterial counts. Tilapia fed the 0.5% OTC or OAB diet had significantly higher resistance to S. agalactiae than those fed the control diet. This study indicates that dietary organic acids can potentially replace OTC as a growth promoter and antimicrobial in tilapia feeds.

Dietary organic acids are increasingly being investigated as a potential means of improving growth and nutrient utilization in aquatic animals. A 9-week study was performed to compare equal amounts (2%) of different organic acids (sodium butyrate, acetate, propionate, or formate) on the growth, muscle proximate composition, fatty acid composition, cholesterol and lipid peroxidation, differential cell counts, plasma biochemistry, intestinal short-chain fatty acid (SCFA) level, and liver histopathology to red hybrid tilapia (Oreochromis sp.) (initial mean weight of 2.87 g). A second experiment was performed to determine their effects on lipid peroxidation and trimethylamine (TMA) when added at 1% to tilapia meat and left out for 24 h. The results of the first experiment showed no treatment effect to growth, feeding efficiencies, or muscle fatty acid composition, but all dietary organic acids significantly decreased intestinal SCFA. Dietary butyrate and propionate significantly decreased muscle lipid peroxidation compared to the control group, but the dietary formate treatment had the lowest lipid peroxidation compared to all treatments. Muscle crude protein and lipid in tilapia fed the formate diet were significantly lower and higher, respectively, and showed evidence of stress based on the differential cell counts, significantly higher plasma glucose and liver glycogen, as well as inflammatory responses in the liver. Although a potential benefit of dietary organic acids was a reduction to lipid peroxidation, this could be accomplished post-harvest by direct additions to the meat. In addition, inclusions of butyrate and propionate to tilapia meat significantly decreased TMA, which might be a more cost-effective option to improve the shelf life of tilapia products.

A 90-day feeding trial was conducted on the growth performance, feeding efficacy, body indices, various hematological and plasma biochemical parameters, and histopathological examination of the gonads from male and female Nile tilapia fingerlings when fed different crude plant extracts from Cinnamomum camphora, Euphorbia hirta, Azadirachta indica, or Carica papaya at 2 g kg(-1) compared to a control diet. This was followed by a 14-day challenge to Streptococcus agalactiae. All treatments were triplicated, and each treatment consisted of 30 fish. Results showed that C. papaya extracts were the most effective at delaying gonadal maturation to both male and female tilapia, as well as significantly increasing (P0.05) growth performance compared to the control treatment. Similarly, dietary C. camphora and E. hirta extracts also significantly improved growth, while no significant growth effect was detected between the A. indica and control treatments (P0.05). Further, crude body lipid was lower in the C. camphora, E. hirta and C. papaya treatments, but was only significantly lower for the E. hirta treatment compared to the control. Meanwhile, none of the hematological or biochemical parameters were significantly affected, although plasma ALT was significantly lower for tilapia fed A. indica compared to the control. After the 14-day bacterial challenge, tilapia fed C. camphora supplementation had significantly higher survival, compared to the control, but was not significantly higher than the other supplemented diets. Results indicate that dietary C. papaya extract can significantly promote growth and delay gonadal maturation to both male and female tilapia, while C. camphora was the most effective prophylactic to S. agalactiae and may be a cost-effective and eco-friendly alternative to antibiotics.