The Efficacy of Moina micrura Enriched with Probiotic Bacillus pocheonensis in Enhancing Survival and Disease Resistance of Red Hybrid Tilapia (Oreochromis spp.) Larvae

The administration of probiotics via live feeds, such as Artemia and rotifers, has gained significant attention. Moreover, indiscriminate use of antibiotics in conventional aquaculture practices in order to prevent or control disease outbreaks has resulted in the occurrence of residues and antimicrobial resistance. Thus, the application of eco-friendly feed additives, such as probiotics, as a safer alternative has received increasing attention in recent years. However, only minimal information on the administration of probiotics via freshwater cladoceran Moina micrura is available despite being commonly used for larval and post-larval feeding of freshwater crustaceans and fish. Thus, this study aimed to evaluate the application of Bacillus pocheonensis strain S2 administered via M. micrura to red hybrid tilapia (Oreochromis spp.) larvae. Bacillus pocheonensis that has been previously isolated from Spirulina sp. was subjected to preliminary in vitro evaluation of antagonistic properties. The agar well-diffusion assay revealed that this probiont could inhibit the growth of Streptococcus agalactiae and Aeromonas hydrophila. The size of inhibition zones ranged from 8.8 ± 0.2 to 18.2 ± 0.4 mm. Moina micrura was later used as a biological model in preliminary in vivo bacterial challenge assays to evaluate the efficacy of B. pocheonensis in protecting the host from diseases. Moina micrura was pre-enriched with B. pocheonensis at 104 and 106 CFU mL-1 before S. agalactiae and A. hydrophila were introduced into the culture. The study revealed that B. pocheonensis at 104 CFU mL-1 was able to significantly enhance the survival of M. micrura after being challenged with both pathogens (63 ± 3%) in comparison to the control group. The relative percentage survival (RPS) of M. micrura was highest (p < 0.05) when treated with B. pocheonensis at both concentrations 104 and 106 CFU mL-1 (38.33) after being challenged against S. agalactiae. To assess the efficacy of B. pocheonensis in protecting red hybrid tilapia against streptococcosis, the larvae were fed with either unenriched (control) Moina or probiont-enriched Moina daily for 10 days. A significantly (p < 0.05) higher survival rate (77 ± 3%) was observed in larvae fed with probiont-enriched M. micrura compared to other treatments, and the RPS was recorded at 62.90. In addition, the S. agalactiae load was suppressed in larvae fed probiont-enriched M. micrura (6.84 ± 0.39 CFU mL-1) in comparison to the control group (7.78 ± 0.09 CFU mL-1), indicating that the probiont might have contributed to the improvement of tilapia health and survival. This study illustrated that M. micrura was suitable to be used as a vector for probiotics in freshwater fish larvae as an alternative to hazardous antibiotics for disease control.

Challenges in Controlling Vibriosis in Shrimp Farms

Recently the shrimp farming has blooming as a crucial counterpart in the aquaculture industry which contribute the remarkable role in sea food production as well economy of the country. However, this could be fluctuated every year through several circumstances such as unfavorable (Poor water and soil quality) environmental factors. The environmental factors includes disease causing bacterial pathogens in the soil and water which causes the bacterial diseases in the aquatic animals, like this hectic problems are prevented through bioaugmentation strategies. The pond environment plays a vital role in determining the healthy culture system, but there is high risk for manipulation by bacterial community which takes care of waste generated in the system through in situ bioremediation. Due to the impact of rapidly growing bacterial diseases of shrimps throughout the world, numerous studies have been carried out to find immunostimulants, immunomodulators and biotic component that can be used against vibrio causing pathogens, and can also be used as an alternative for antibiotics. Recent research focus towards the marine resources such as microalgae, seaweed, live feeds (like artemia, copepods, rotifers), bacteriophage, and probiotics have been found to have higher potential in reducing vibriosis. Eco-based shrimp farming includes green water technology, phage therapy bio-floc technology (BFT) and integrated multi-trophic aquaculture (IMTA), these methods hold a promising alternative to antibiotics in the near future. Bacterial diseases caused by vibrios have been reported in penaeid shrimp culture systems implicating at least 14 species and they are Vibrio harveyi, V. splendidus, V. parahaemolyticus, V. alginolyticus, V. anguillarum, V. vulnificuslogei etc.

Automated CNN back-propagation pipeline generation for FPGA online training

Training of convolutional neural networks (CNNs) on embedded platforms to support on-device learning has become essential for the future deployment of CNNs on autonomous systems. In this work, we present an automated CNN training pipeline compilation tool for Xilinx FPGAs. We automatically generate multiple hardware designs from high-level CNN descriptions using a multi-objective optimization algorithm that explores the design space by exploiting CNN parallelism. These designs that trade-off resources for throughput allow users to tailor implementations to their hardware and applications. The training pipeline is generated based on the backpropagation (BP) equations of convolution which highlight an overlap in computation. We translate the overlap into hardware by reusing most of the forward pass (FP) pipeline reducing the resources overhead. The implementation uses a streaming interface that lends itself well to data streams and live feeds instead of static data reads from memory. Meaning, we do not use the standard array of processing elements (PEs) approach, which is efficient for offline inference, instead we translate the architecture into a pipeline where data is streamed through allowing for new samples to be read as they become available. We validate the results using the Zynq-7100 on three datasets and varying size architectures against CPU and GPU implementations. GPUs consistently outperform FPGAs in training times in batch processing scenarios, but in data stream scenarios, FPGA designs achieve a significant speedup compared to GPU and CPU when enough resources are dedicated to the learning task. A 2.8×, 5.8×, and 3× speed up over GPU was achieved on three architectures trained on MNIST, SVHN, and CIFAR-10 respectively.

The Effects of Live Feeding on Swimming Activity and Exhibit Use in Zoo Humboldt Penguins (Spheniscus humboldti)

Penguins are considered among the most popular animals for zoo and aquarium visitors to observe. Swimming is considered a desirable activity, both for the visitor experience and the welfare of the penguins. However, little is known about the amount of time exhibited penguins spend swimming, or how such swimming is related to regular feeding events. We examined the effects of introducing live prey in the form of trout on 22 Humboldt penguins living at the Woodland Park Zoo. Of primary interest was how the live feeds changed (1) daily and hourly swimming activity, and (2) variability in enclosure use. We hypothesized that the live feedings would increase swimming activity prior to and during the delivery of the live trout, as well as create an overall increase in total swimming activity for live feed days compared to non-live feed days. We also predicted that the penguins would be more likely to use the entire exhibit around these live feeds, since they are likely to chase fish throughout the exhibit. Penguins did show an increase in swimming activity in the hour prior to and during the live feed, with a small decrease in swimming activity following the live feed when compared to non-live feed days. There was also a more than 30% increase in the total swimming activity for live feed days when compared to all other non-live feed days. In addition, a single measure of variability in enclosure use (entropy) showed greater overall enclosure use for the live feed days compared to the non-live feed days. These results demonstrate that live fish can be a useful way of enriching the behavioural welfare of Humboldt penguins.

Replacement of Artemia spp. with zooplankton in Penaeus vannamei larviculture

Supplying healthy and cost-effective postlarvae is critical to the success of the shrimp industry. Given the cost of Artemia in larvae culture, there is considerable interest in using alternative live feeds such as copepods. This study's objective was to evaluate five diets with different proportions of Artemia and copepods offered to Penaeus vannamei larvae. Biological factors such as growth, survival to postlarvae, and final weights were evaluated in conjunction with economic factors. The diets offered were: 1) 100% Artemia 2) 75% Artemia and 25% copepods 3) 50% Artemia and 50% copepods 4) 25% Artemia and 75% copepods and 5) 100% copepods. Concerning the biological response, there were no significant differences observed between the five treatments. The economic evaluation was based on a partial budget. It was concluded that there were no significant differences in survival or yields. However, the data collected in this experiment concluded that the treatment with 100% Artemia had higher annual net benefits due to the combined effect of survival rates and cost. These net benefits can vary in other repetitions, so it is recommended to experiment more times to observe differences in profits among diets.

Probiotic correction of Daphnia magna microbial profile using Lactobacillus casei UCM7280

The anthibiotics use in aquaculture these days is severely restricted by European standarts of marketable fish products quality. According to this, one of the most efficient alternatives are probiotics. So the search of applicable probiotic microorganisms that can be applied in aquaculture is relevant. On the other side, probiotics introduction into the fish body is usually accomplished in composition with dry feed as a biofilm. But a lot of fish larvae are not capable of consuming dry artificial feed due to numerous reasons. For their transmission for endogenic nourishment from exogenic live feeds are used in aquaculture, which have a higher level of digestibility compared to granulated feed. One more advantage of live feed is that they can be used as vectors to provide the targeted delivery of probiotics into fish body. In this work Lactobacillus casei IMV 7280 was firsly tested for the needs of aquaculture. It is shown that the usage of this probiotic during the growing of carp whitebaits stimulates it growth and leads to unwanted microflora suppresion in water as well as in fish bodies. The optimal schedule of L. сasei UCM 7280 bioencapsulation into live feed with Daphnia magna as an example is designed and suggested. It is shown that bioencapsulation procedure realization does not repress D. magna΄s normal mocrobiome, provides the increase of proteins and lipids level for 1,2 and 1,4 times accordingly and spends up the increasing of density level of fodder organisms.