The Feasibility of Using Agarophyte Processing Waste

When agarophytes are processed, 16-89% algal waste (AW) is formed. Due to the high content of minerals in this waste and the presence of proteins that are resistant to the action of proteolytic enzymes, such AW is mainly used in the production of feed for farm animals. The significant content of polysaccharides in dry AW indicates that it could be used as a raw material for the production of dietary fiber (DF). Due to the difference in the chemical composition of AW depending on the type of red algae, different approaches for its deproteinization have been used. Thus, a 3% alkali solution should be used for the deproteinization of algal waste from the red algae Gracilaria, a 0.5% alkali solution for GelidiumAW, and a 1% sodium carbonate solution for A. plicataAW.The duration of the deproteinization process is 30 min at a temperature of 97±2 ∘C for all types of AW. In this study, functional and technological solutions of DF from AW were developed. The results showed that their water binding capacity was 6-22 g of water per 1 g of the preparation, the fat binding capacity was 1.6-3.3 g of fat per 1 g of the preparation, and the swelling capacity was 46-312% depending on the type of red algae.The obtained DF was used in the production of minced fish food products of the ‘fish sticks’ type, based on minced fish and consisting of cod and pink salmon. The study of the chemical composition and calorie content of the developed food product showed the possibility of its use in dietary nutrition. Keywords: red algae, algal waste, deproteinization, dietary fiber

Establishment of metrological parameters of the method for measuring the protein mass fraction in fish food products by the Kjeldahl method

In laboratory practice, there are many protein quantification methods, and all of them have their own advantages and disadvantages. The most common and widely used method for the protein analysis in food products, including fish, is the Kjeldahl method. However, the current standards for measurement methods for the determination of the protein content in fish food products do not provide for the use of devices that meet the modern level of technical development, and also do not contain metrological indicators that guarantee the reliability of the results obtained. The aim of the study was to substantiate the method for measuring the protein mass fraction in fish food products by the Kjeldahl method on an automatic analyzer and to establish metrological parameters. The assessment of the quality indicators of the Kjeldahl measuring method was carried out using a Kjeltec System 2300 Nitrogen Analyzer (Foss Analytical AB, Sweden) in the form of a characteristic of the measurement error and its components, which will provide results with the required accuracy.

Histological digestive tract of milkfish’s (Chanos chanos Forskal.) from District Ujung Pangkah, Gresik

Milkfish is a commodity with a high production rate. From the milkfish commodity, Gresik is the center of fishery production in East Java. Milkfish belongs to the herbivore group with the type of food from the plant group. Milkfish cultivation in traditional ponds still uses natural food as the main food for the cultivated commodities. Fish food affects the structure of the digestive tract, especially the intestines of fish. herbivorous fish have very long intestines even many times the body length, compared to omnivorous and carnivorous fish. Thus, this study aims to find out more clearly about the structure of the milkfish gut tissue. The digestive tract is related to the process of digestion, absorption and disposal of food waste, so it has an important role in the growth of fish. The research method used was descriptive experimental by making preparations of fish intestinal tissue and staining with Hematoxylin Eosin. The intestines of the fish observed were the front, middle and back. Observation of the preparations using a microscope with a dot slide scan photo. From the results of the study obtained an overview of the intestinal tissue structure of the upper (proximal), middle (middle) and lower (distal) fish. The structure of the front, middle and back of the milkfish gut tissue is similar, the difference lies in the number and thickness of the villi.

The future of fish in Africa: Employment and investment opportunities

One of the most pressing challenges facing food systems in Africa is ensuring availability of a healthy and sustainable diet to 2.4 billion people by 2050. The continent has struggled with development challenges, particularly chronic food insecurity and pervasive poverty. In Africa’s food systems, fish and other aquatic foods play a multifaceted role in generating income, and providing a critical source of essential micronutrients. To date, there are no estimates of investment and potential returns for domestic fish production in Africa. To contribute to policy debates about the future of fish in Africa, we applied the International Model for Policy Analysis of Agriculture Commodities and Trade (IMPACT) to explore two Pan-African scenarios for fish sector growth: a business-as-usual (BAU) scenario and a high-growth scenario for capture fisheries and aquaculture with accompanying strong gross domestic product growth (HIGH). Post-model analysis was used to estimate employment and aquaculture investment requirements for the sector in Africa. Africa’s fish sector is estimated to support 20.7 million jobs in 2030, and 21.6 million by 2050 under the BAU. Approximately 2.6 people will be employed indirectly along fisheries and aquaculture value chains for every person directly employed in the fish production stage. Under the HIGH scenario, total employment in Africa’s fish food system will reach 58.0 million jobs, representing 2.4% of total projected population in Africa by 2050. Aquaculture production value is estimated to achieve US$ 3.3 billion and US$ 20.4 billion per year under the BAU and HIGH scenarios by 2050, respectively. Farm-gate investment costs for the three key inputs (fish feeds, farm labor, and fish seed) to achieve the aquaculture volumes projected by 2050 are estimated at US$ 1.8 billion per year under the BAU and US$ 11.6 billion per year under the HIGH scenario. Sustained investments are critical to sustain capture fisheries and support aquaculture growth for food system transformation towards healthier diets.

IoT System on Dynamic Fish Feeder Based on Fish Existence for Agriculture Aquaponic Breeders

Maintaining and breeding fish in a pond are a crucial task for a large fish breeder. The main issues for fish breeders are pond management such as the production of food for fishes and to maintain the pond water quality. The dynamic or technological system for breeders has been invented and becomes important to get maximum profit return for aquaponic breeders in maintaining fishes. This research presents a developed prototype of a dynamic fish feeder based on fish existence. The dynamic fish feeder is programmed to feed where sensors detected the fish's existence. A microcontroller board NodeMCU ESP8266 is programmed for the developed hardware. The controller controls the feeding and feedback mechanism based on attached sensors. An ultrasonic sensor is programmed with the controller to detect the level of food and waterproof ultrasonic to detect existing fish. The humidity sensor was used to measure the humidity in the food container to control the food freshness. Two servo motors were used to move the waterproof sensor to attract the fish and to dispense the food to the fish when existed. The result presents four measured levels that are the temperature of the food container, the quality of food based on humidity measured, fish detection counter and level of fish food in the container. Data analytics on all the measured levels was presented on the ThingSpeak platform by using Blynk to get data collections from all sensors. This research is significant for fish breeders that support IR4.0 system connected online and mobile apps which also contribute to today’s agriculture.

PELATIHAN ENRICHMENT DAPHNIA UNTUK MENINGKATKAN KECERAHAN WARNA IKAN CUPANG (Betta sp.)

ABSTRAKPermasalahan yang dihadapi mitra adalah rendahnya kualitas warna ikan cupang yang mitra peroleh dari agen, sehingga harga jual ikan cupang juga rendah. Setelah mengetahui permasalahan mitra, tim menawarkan solusi yaitu pelatihan enrichment Daphnia untuk memanipulasi pigmen warna ikan cupang. Tujuan dari pengabdian ini adalah memberikan pelatihan kepada pemuda dan para penggiat ikan cupang di Gampong Teungoh, Kota Langsa tentang enrichment Daphnia sebagai pakan ikan cupang yang dapat meninngkatkan kecerahan warna ikan cupang. Metode yang digunakan adalah sosialisasi dan penjaringan mitra, pemberian materi tentang faktor-faktor yang mempengaruhi kecerahan warna ikan cupang serta teknik enrichment pakan ikan cupang dan pelatihan teknik enrichment pakan ikan cupang. Mitra yang mengikuti kegiatan ini adalah pemuda gampong dan penggiat ikan cupang di Gampong Teungoh yang berjumlah 25 orang. Evaluasi keberhasilan pelatihan dihitung berdasarkan kepahaman para peserta terhadap materi pelatihan. Hasil yang dicapai dari pelatihan ini yaitu adanya peningkatan ketrampilan para pemuda dan penggiat ikan cupang dalam meningkatkan warna ikan cupang dan juga adanya peningkatan harga jual ikan yang telah diberikan pakan Daphnia yang telah di enrichment. Kata kunci: astaxhantin; daphnia; ikan cupang; kecerahan warna; pakan alami. ABSTRACTThe problem faced by partners is the low quality of betta fish colors that partners get from agents, so the selling price of betta fish is also low. After knowing the partners' problems, the team offered a solution, namely Daphnia enrichment training to manipulate betta fish color pigments. The purpose of this service is to provide training to youth and betta fish activists in Gampong Teungoh, Langsa City on the enrichment of Daphnia as betta fish food that can increase the brightness of the color of betta fish. The methods used were socialization and partner networking, providing material about the factors that affect the color brightness of betta fish and betta fish feed enrichment techniques and training on betta fish feed enrichment techniques. Partners who participated in this activity were village youth and betta fish activists in Teungoh Village, totaling 25 people. The evaluation of the success of the training is calculated based on the participants' understanding of the training material. The results achieved from this training are an increase in the skills of young people and betta fish activists in increasing the color of betta fish and also an increase in the selling price of fish that have been given enrichment Daphnia feed. Keywords: astaxhantin; daphnia; betta fish; color brightness; natural food

Culex quinquefasciatus larvae development arrested when fed on Neochloris aquatica

Culex quinquefasciatus is a cosmopolitan species widely distributed in the tropical and subtropical areas of the world. Due to its long history of close association with humans, the transmission of arboviruses and parasites have an important role in veterinary and public health. Adult females feed mainly on birds although they can also feed on humans and other mammals. On the other hand, larvae are able to feed on a great diversity of microorganisms, including microalgae, present in natural or artificial breeding sites with a high organic load. These two particularities, mentioned above, are some of the reasons why this mosquito is so successful in the environment. In this work, we report the identification of a microalga found during field sampling in artificial breeding sites, in a group of discarded tires with accumulated rainwater. Surprisingly, only one of them had a bright green culture without mosquito larvae while the other surrounding tires contained a large number of mosquito larvae. We isolated and identified this microorganism as Neochloris aquatica, and it was evaluated as a potential biological control agent against Cx. quinquefasciatus. The oviposition site preference in the presence of the alga by gravid females, and the effects on larval development were analyzed. Additionally, microalga effect on Cx. quinquefasciatus wild type, naturally infected with the endosymbiotic bacterium Wolbachia (w+) and Wolbachia free (w−) laboratory lines was explored. According to our results, even though it is chosen by gravid females to lay their eggs, the microalga had a negative effect on the development of larvae from both populations. Additionally, when the larvae were fed with a culture of alga supplemented with balanced fish food used as control diet, they were not able to reverse its effect, and were unable to complete development until adulthood. Here, N. aquatica is described as a biological agent, and as a potential source of bioactive compounds for the control of mosquito populations important in veterinary and human health.

Phytoplankton Fuel Fish Food Webs in a Low-Turbidity Temperate Coastal Embayment: A Stable Isotope Approach

Trophic contributions of diverse OM sources to estuarine and coastal food webs differ substantially across systems around the world, particularly for nekton (fish, cephalopods, and crustaceans), which utilize basal resources from multiple sources over space and time because of their mobility and feeding behaviors at multiple trophic levels. We investigated the contributions of putative OM sources to fish food webs and assessed the spatiotemporal patterns, structures, and trophic connectivity in fish food webs across four seasons from three closely spaced (10–15 km) sites: an estuarine channel (EC), a deep bay (DB), and an offshore (OS) region in Gwangyang Bay, a high-productivity, low-turbidity estuarine embayment off the Republic of Korea. While nearly all previous studies have focused on few representative species, we examined δ13C and δ15N values of whole nekton communities along with dominant benthic macro-invertebrates, zooplankton, and their putative primary food sources. The δ13C and δ15N values coupled with MixSIAR, a Bayesian mixing model, revealed that these communities utilized multiple primary producers, but phytoplankton comprised the primary trophic contributor (46.6–69.1%). Microphytobenthos (15.8–20.4%) and the seagrass Zostera marina (8.6–19.8%) made substantial contributions, but the role of river-borne terrestrial organic matter was negligible. Spatially different species composition and stable isotope values, but higher utilization of coastal phytoplankton by estuarine fish, indicated disparate food webs structures between the EC and DB/OS coastal areas, with considerable trophic connectivity. Greater overlaps in fish and cephalopod isotopic niches than among other consumers and a higher estimated carbon trophic enrichment factor for EC nekton confirmed feeding migration-mediated biological transport of coastal OM sources to the estuary. Further, the seasonally consistent structures and resource utilization patterns indicate that fish food webs are resilient to changes at lower trophic levels. Our results contrast with those for other highly turbid coastal systems depending highly on diversified basal sources, including exported terrestrial and wetland detritus alongside autochthonous phytoplankton. Finally, this study provides a novel perspective on the role of OM sources in such low turbidity and highly productive coastal embayments and enhances our understanding of marine ecosystems.

Vaccination of Gilthead Seabream After Continuous Xenoestrogen Oral Exposure Enhances the Gut Endobolome and Immune Status via GPER1

In fish culture settings, the exogenous input of steroids is a matter of concern. Recently, we unveiled that in the gilthead seabream (Sparus aurata), the G protein-coupled estrogen receptor agonist G-1 (G1) and the endocrine disruptor 17α-ethinylestradiol (EE2) are potent modulators in polyreactive antibody production. However, the integral role of the microbiota upon immunity and antibody processing in response to the effect of EE2 remains largely unexplored. Here, juvenile seabreams continuously exposed for 84 days to oral G1 or EE2 mixed in the fish food were intraperitoneally (i.p.) immune primed on day 42 with the model antigen keyhole limpet hemocyanin (KLH). A critical panel of systemic and mucosal immune markers, serum VTG, and humoral, enzymatic, and bacteriolytic activities were recorded and correlated with gut bacterial metagenomic analysis 1 day post-priming (dpp). Besides, at 15 dpp, animals received a boost to investigate the possible generation of specific anti-KLH antibodies at the systemic and mucosal interphases by the end of the trial. On day 43, EE2 but not G1 induced a significant shift in the serum VTG level of naive fish. Simultaneously, significant changes in some immune enzymatic activities in the serum and gut mucus of the EE2-treated group were recorded. In comparison, the vaccine priming immunization resulted in an attenuated profile of most enzymatic activities in the same group. The gut genes qPCR analysis exhibited a related pattern, only emphasized by a significant shift in the EE2 group’s il1b expression. The gut bacterial microbiome status underwent 16S rRNA dynamic changes in alpha diversity indices, only with the exposure to oral G1, supporting functional alterations on cellular processes, signaling, and lipid metabolism in the microbiota. By the same token, the immunization elevated the relative abundance of Fusobacteria only in the control group, while this phylum was depleted in both the treated groups. Remarkably, the immunization also promoted changes in the bacterial class Betaproteobacteria and the estrogen-associated genus Novosphingobium. Furthermore, systemic and mucosal KLH-specific immunoglobulin (Ig)M and IgT levels in the fully vaccinated fish showed only slight changes 84 days post-estrogenic oral administration. In summary, our results highlight the intrinsic relationship among estrogens, their associated receptors, and immunization in the ubiquitous fish immune regulation and the subtle but significant crosstalk with the gut endobolome.