Commercial Pellets Research Articles

Protocol for the production of micro- and nanoplastic test materials

Micro- and nanoplastics (MNP) are ubiquitous, but little is known about the risks they pose to human health. Currently available data are of limited use for developing relevant risk assessments due to poor quality control, the lack of a standardised approach to particle characterisation and environmental analysis, and the use of test materials that do not reflect those found in the environment. A set of well-characterised MNP test materials would greatly alleviate this. Here, we present a robust method to produce, fractionate and characterise such test materials of PP and PVC. Initial size reduction of commercial powders or pellets to 500 µm was performed using a centrifugal mill under cryogenic conditions. Further ball-milling between room temperature and -50 °C in 1-propanol was then performed to reach the final particle sizes. Fractionation into size ranges of < 1, 1–5, 5–10, 10–30, 90–180 and 180–300 µm was performed by sedimentation and filtration. Characterisation of the reference materials through SLS, SEM–EDX, XRF and TGA demonstrated that the fractions were of the desired size and levels of contamination from the procedure were < 1 wt%. Stability testing in both 1-propanol and 0.05 wt% BSA solution showed that whilst some agglomeration occurred during storage in 1-propanol the suspensions were stable in BSA over 9 months and some of the previous agglomeration was reversed.

10 Preliminary Effect of Cottonseed as a Source of Gossypol on Hepatic Portal Blood Flow as an Indicator of Metabolism in Meat does Artificially Infected withHaemonchus Contortus

Abstract Cottonseed diets provide animals with increased levels of protein and energy to support growth. Recently, it was suggested that although the gossypol content of cottonseed could result in adverse animal reproduction, it could have a potential anthelmintic property beneficial to small ruminant operations. In addition, gossypol is primarily cleared and excreted from the animal via liver glucuronidation, which is a primary pathway for steroid clearance in ruminants. The objective of this experiment was to determine the effect of a cottonseed diet and parasite load on the hepatic portal blood flow an indicator of hepatic clearance rates and metabolism. Forty Boer x Spanish cross does were assigned to of 4 treatments (n = 10 per treatment group) in a 2x2 factorial design consisting of cottonseed supplementation and no parasite infection (CNP), cottonseed supplementation plus artificial infection with Haemonchus contortus (CP), commercial pellets with no parasite infection (NCNP), or commercial pellets plus artificial infection with Haemonchus contortus (NCP). On week 8 post-treatment, hepatic portal blood flow measurements were collected via Doppler ultrasonography on the right side of the animal at the 10th intercostal space. Blood flow was then calculated using the following equation: blood flow (mL/min) = mean velocity (cm/s) x vessel area x 60 seconds. The mean velocity was calculated by the following formula: (systolic – diastolic)/pulsatility index. Hepatic portal blood flow and body weight of does were analyzed with a One-way ANOVA using the MIXED procedure of SAS with diet and parasite load as the main effects and their interactions. A diet by parasite interaction (P = 0.026) was observed for the mean velocity of the hepatic portal vein, which was decreased in CP versus CNP treatments. A diet by parasite interaction (P = 0.012) was observed for the diameter of the hepatic portal vein, which was increased in the CP treatment versus all other groups. However, absolute hepatic portal blood flow was not different (P &amp;gt; 0.12) amongst treatments. A tendency for the main effect (P = 0.087) of diet was observed for hepatic portal blood flow relative to body weight, which was an increase in cottonseed (27.8 ±.8 mL/min*kg) versus NCS (23.2 ±.8 mL/min*kg). Body weight was not different (P &amp;gt; 0.35) amongst treatments at the time of Doppler ultrasound examination. In conclusion, cottonseed interacted with parasites to decrease mean velocity and increase the diameter of the portal vein. In addition, cottonseed appears to increase liver blood flow relative to body weight. This change in relative liver blood flow could have implications for mediating hepatic metabolism and clearance.

Immunogenicity and Efficacy of a Feed-Based Bivalent Vaccine against Streptococcosis and Motile Aeromonad Septicemia in Red Hybrid Tilapia (Oreochromis sp.).

Streptococcosis and motile Aeromonad septicemia (MAS) are the main bacterial diseases in tilapia culture worldwide, causing significant economic losses. Vaccination is an effective method of preventing diseases and contributes to economic sustainability. This study investigated the immuno-protective efficacy of a newly developed feed-based bivalent vaccine against streptococcosis and MAS in red hybrid tilapia. The feed-based bivalent vaccine pellet was developed by incorporating the formalin-killed S. agalactiae and A. hydrophila antigens into a commercial feed pellet with palm oil as the adjuvant. The bivalent vaccine was subjected to feed quality analyses. For immunological analyses, 900 fish (12.94 ± 0.46 g) were divided into two treatment groups in triplicate. Fish in Group 1 were unvaccinated (control), while those in Group 2 were vaccinated with the bivalent vaccine. The bivalent vaccine was delivered orally at 5% of the fish's body weight for three consecutive days on week 0, followed by boosters on weeks 2 and 6. Lysozyme and enzyme-linked immunosorbent assays (ELISAs) on serum, gut lavage, and skin mucus were performed every week for 16 weeks. Lysozyme activity in vaccinated fish was significantly (p ≤ 0.05) higher than in unvaccinated fish following vaccination. Similarly, the IgM antibody levels of vaccinated fish were significantly (p ≤ 0.05) higher after vaccination. The bivalent vaccine provided high protective efficacy against S. agalactiae (80.00 ± 10.00%) and A. hydrophila (90.00 ± 10.00%) and partial cross-protective efficacy against S. iniae (63.33 ± 5.77%) and A. veronii (60.00 ± 10.00%). During the challenge test, fewer clinical and gross lesions were observed in vaccinated fish compared with unvaccinated fish. Histopathological assessment showed less severe pathological changes in selected organs than the unvaccinated fish. This study showed that vaccination with a feed-based bivalent vaccine improves immunological responses in red hybrid tilapia, and thus protects against streptococcosis and MAS.

Survival and Growth of Pangasianodon hypopthalmus Fed with Moringa oleifera Enriched Pellets and Reared in Tank With Aquaponic System and Dark Condition

Pangasianodon hypophthalmus grows well in a dark tank completed with an aquaponic system. To improve the growth, a feed supplement made from Moringa oleifera might be used as it is rich in protein, vitamins A, B, C, and minerals. To understand the effect of M.oleifera addition in the feed of fish, research has been conducted in June-July 2022. M. oleifera leaves were dried and powdered and then mixed with commercial fish feed pellets. There were 4 treatments of M. oleifera dosages, namely T0 (no M. oleifera), T1 (10 g/kg), T2 (15 g/kg), and T3 (20 g/kg). The fish was reared in a 100L container (30 fishes/tank, around 4 g BW and 8 cm TL), covered with a dark-colored tarp, and completed with the aquaponic system using Ipomoea aquatica. The feed was given 2 times/day, ad libitum. Samplings were conducted once/10 days, for 40 days. Results showed that the survival of fish in all treatments was 93.3 – 98.89%. The growth of fish, however, was different. There was no difference in fish body weight (BW), total length (TL), and specific growth rate (SGR) of fish fed with Moringa, they were around 23.5 g BW, 5.8 cm TL, and 4.3 cm SGR respectively. While those of the control fish were 13.0 g BW, 4.23 cm TL, and 2.89% per day SGR respectively. The fish that was fed with Moringa-enriched pellets showed the highest Feed Efficiency (90.42-97.46%) and the lowest FCR (1.03 – 1.11). While in the fish that was not fed with Moringa showed the lowest FE (75.48%) and the highest FCR (1.33%). Data obtained indicate that Moringa positively improves the growth of fish as well as improving feed efficiency

Gastric evacuation in European seabass Dicentrarchus labrax (Linnaeus, 1758), forced-fed on commercial pellets

The effects of meal size and body size on gastric evacuation rates were parameterised for European seabass Dicentrarchus labrax (Linnaeus, 1758). A total of three gastric evacuation experiments were performed on small (15.7±0.8 cm) and large (21.5±0.4) size fish forced-fed with meals of 0.5 and 1.5 g composed of commercial pellets. The stomach contents were then recovered by serial slaughtering the fish at predetermined post-prandial times. The surface-area dependent function adequately describes the gastric evacuation in European seabass independently of meal size. A power function of fish length L was then employed to evaluate the impact of body size, revealing its notable effect on gastric evacuation rates of European seabass. Keywords: Aquaculture, Feeding regimes, General power function, Surface-area dependent

An evaluation of the growth and immunity of New Zealand black-footed abalone (Haliotis iris) treated with encapsulated feed and probiotics

Encapsulation technology has been applied in aquaculture for developing more efficient delivery systems of nutrients and probiotics to various species. This study aims to investigate the effect of an encapsulated probiotics feed on the growth and health of New Zealand black-footed abalone (Haliotis iris). Juvenile abalone were fed with four different dietary treatments, including commercial pellets, commercial feed sprayed with probiotics, combination of commercial feed and chitosan-coated alginate (CCALG) beads containing probiotics and CCALG beads containing both probiotics and nutrients. A multi-technique approach was used to evaluate the growth performance and health parameters of the experimental animals after 57 days in feeding trial. The results showed a significantly higher growth rate (p < 0.05) in shell length (50.06 ± 5.91 µm/day) and weight (25.55 ± 2.55 mg/day) of abalone fed with CCALG beads containing both probiotics and nutrients (optimal diet) compared to the other groups. The feed conversion rate (FCR) for abalone fed with the optimal diet (1.04 ± 0.06) was significantly (p < 0.05) lower than the other experimental diets. Furthermore, a low level of haemocytes with reactive oxygen species (ROS) was found associated with the optimal diet (13.24 ± 4.2%). A total of 31 differently regulated metabolites across the four treatments were revealed with a characteristic enhancement of free amino acids in the samples obtained from abalone fed with the optimal diet. The combined results from the growth parameters, flowcytometry and metabolomics indicate that CCALG beads encapsulating probiotics and nutrients can efficiently improve the growth and immunity of juvenile abalone.

Faecal waste characteristics of yellowtail kingfish (Seriola lalandi) fed with pelleted and natural feed

Yellowtail kingfish (Seriola lalandi) is a fast-growing fish species. One of the challenges of farming yellowtail kingfish in recirculating aquaculture systems is their poor faeces integrity, also referred to as ‘diarrhoea-like’ faeces. Whether diarrhoea-like faeces occur under conditions when feeding on its natural feed items or are diet induced, is unclear. This study assessed the effect of feed type (pelleted vs. natural feed) on the faecal characteristics and faecal waste production of yellowtail kingfish. Three dietary treatments were studied over a 35-d experimental period: a pelleted diet based on marine ingredients (Marine; open formula); an experimental pelleted feed based on the ingredient composition of a commercial kingfish feed (Commercial Dummy, CD; closed formula); and a diet composed of four, individually fed raw (unprocessed) natural ingredients and commercial dummy pellets at a ratio of 1:1 on dry matter basis (Natural and Commercial Dummy, NCD). The NCD treatment was intended to clarify whether diarrhoea-like faeces are naturally occurring in yellowtail kingfish. Each dietary treatment was tested in four tanks, which were stocked with 27 yellowtail kingfish (mean initial weight 39 g). Fish were fed to apparent satiation twice daily for 1 h. For each tank nutrient digestibility and faecal characteristics were measured. The inclusion of natural ingredients reduced the faecal waste production (p < 0.001). Furthermore, the faeces integrity of yellowtail kingfish fed with natural ingredients was not poor (not diarrhoea-like). At the natural treatment, fish excreted faecal pellets and short strings, which were not observed at the other treatments. Faecal waste collected from fish receiving only pelleted feed was classified as diarrhoea-like. The highest faeces removal efficiency by settling was observed at the NCD treatment compared to the other treatments (p < 0.001). Consequently, the lowest amount of non-removed faeces per feed intake (p < 0.001) was observed at the NCD treatment (62.9 g OM/kg OM FI), followed by the Marine (101.1 g OM/kg OM FI) and Commercial Dummy treatment (111.7 g OM/kg OM FI). In conclusion, this study shows the potential of dietary interventions to alter the amount and integrity of faecal waste. This offers possibilities to reduce the total suspended solid load for yellowtail kingfish farming in recirculating aquaculture systems.

Effect of Different Salinity on Osmolarity and Survival of Common Carp (Cyprinus carpio) with Fed Fermented Herbs

Giving fermented herbs feed can increase appetite, feed digestibility, growth, and fish health. Rearing fish in salinity media aims to find the best salinity levels for osmolarity and survival, so that fresh water fish can also be reared in saline waters. This study used an experimental method with a completely randomized design (CRD), 5 treatment levels 3 replications, namely P0(0 ppt), P1(3 ppt), P2(6 ppt), P3(9 ppt), and P4(12 ppt). Salinity treatment was made by diluting seawater (35‰) with fresh water. The test fish used were common carp measuring 6-8 cm, kept in an aquarium measuring 60x40x40cm with a stocking density of 1 fish/3 liters of water. The feed given was in the form of commercial pellets plus fermented herbs at a dose of 200 mL/kg of feed dissolved in 500 mL of clean water. This research was conducted for 60 days. The results showed that the osmolarity of carp for 60 days of rearing ranged from 135-332 mOsm/kg H2O The highest absolute weight growth in P2 with a value (10.52 g) and lowest at P4 (8.36 g). The highest survival rate of carp was in the P0, P1 and P2 with a value (100%), while in P3(95%) and P4(75%). Common carp are able to tolerate salinity levels up to 12 ppt.

Optimization of Sago Dregs as Pellet Feed of Broiler in Tanjung Meranti Islands Village

Tanjung Kepulauan Meranti Village, Riau has production large sago plants so that the waste is used as animal feed with pellet technology. The purpose of this service to utilize sago pulp that has not been used as feed of broiler. The service method uses PAR, which is a method of involving community groups as whole in research activities so that positive social change occurs. The results show that community groups are very enthusiastic about participating in community service activities with indicators the ease with which community groups understand the material provided. Some of the material conveyed that sago pulp can be fermented to increase nutritional value, especially protein and reduce crude fiber, then fermented sago pulp can be used as broiler feed pellets. In conclusion, sago pulp can be used as a pellet product at a low price as an alternative to commercial pellet feed to reduce costs in broiler farming

Composition of Chinook salmon faecal wastes with implications for environmental management

Intensive salmon aquaculture is now a major industry globally, with Chinook salmon (Oncorhynchus tshawytscha) the dominant culture species in New Zealand. Understanding the composition of Chinook salmon wastes is important for assessing environmental risks of coastal open-cage aquaculture, both in terms of nutrient inputs, and for evaluating potential characteristics that could be used as fish waste markers in the environment. The aim of our study was to describe the biochemical composition of faecal waste from Chinook salmon with a view to describing the characteristics most important for assessing waste inputs in the environment. A broad suite of biochemical characteristics, including nutrient, mineral and trace element concentrations, bulk carbon and nitrogen stable isotope and compound specific Ᵹ13C fatty acid and amino acid values, were measured during an experiment on fish kept in a recirculating aquaculture system (RAS) and fed a standard commercial pellet diet. We found that all biochemical characteristics of feed were conserved in faecal material, but some were conserved better than others. Fatty acid composition was similar in feed and faeces, but element profiles differed and showed high variability in faeces. Carbon and nitrogen bulk stable isotope values of faecal samples were generally lower than mean feed signatures, particularly for Ᵹ15N. For compound specific stable isotopes, the Ᵹ13C values in most fatty acids were similar to that of feed, however, Ᵹ13C values in amino acids were lower (with the exception of phenylalanine and glutamic acid). Based on our findings, we suggest that it may be possible to predict biochemical composition of faeces for well-conserved, or predictably-altered indicators using composition of feed samples alone. The differences between feed and faeces for some markers (e.g., elements, nutrient ratios, Ᵹ15N and Ᵹ13C in amino acids) may be useful for distinguishing between the presence of these two farm-derived wastes in the environment. Our results also suggest that the elemental composition of Chinook salmon waste is generally similar to that of other salmonid species, and supports the transfer of element composition data from other salmonids when setting mass balance model parameters for Chinook salmon.

Performance of Particulate and Structured Pt/TiO2-Based Catalysts for the WGS Reaction under Realistic High- and Low-Temperature Shift Conditions

The water–gas shift (WGS) activity of Pt/TiO2-based powdered and structured catalysts was investigated using realistic feed compositions that are relevant to the high-temperature shift (HTS) and low-temperature shift (LTS) reaction conditions. The promotion of the TiO2 support with small amounts of alkali- or alkaline earth-metals resulted in the enhancement of the WGS activity of 0.5%Pt/TiO2(X) catalysts (X = Na, Cs, Ca, Sr). The use of bimetallic (Pt–M)/TiO2 catalysts (M = Ru, Cr, Fe, Cu) can also shift the CO conversion curve toward lower temperatures, but this is accompanied by the production of relatively large amounts of unwanted CH4 at temperatures above ca. 300 °C. Among the powdered catalysts investigated, Pt/TiO2(Ca) exhibited the best performance under both HTS and LTS conditions. Therefore, this material was selected for the preparation of structured catalysts in the form of pellets as well as ceramic and metallic catalyst monoliths. The 0.5%Pt/TiO2(Ca) pellet catalyst exhibited comparable activity with that of a commercial WGS pellet catalyst, and its performance was further improved when the Pt loading was increased to 1.0 wt.%. Among the structured catalysts investigated, the best results were obtained for the sample coated on the metallic monolith, which exhibited excellent WGS performance in the 300–350 °C temperature range. In conclusion, proper selection of the catalyst structure and reaction parameters can shift the CO conversion curves toward sufficiently low temperatures, rendering the Pt/TiO2(Ca) catalyst suitable for practical applications.

Characterisation of the Gut Bacteria of Cultured and Wild Spiny Lobster Panulirus ornatus

The commercial onshore aquaculture of the spiny lobster Panulirus ornatus, while in its infancy, has progressed rapidly from the enabling research that continues at the University of Tasmania. The development of lobster feeds, both fresh and manufactured, has been critical to the success of this emerging aquaculture sector. Fresh feeds derived from mussel represent the gold standard in terms of the growth performance of juvenile lobsters. Nonetheless, concerns regarding availability, sustainability, and potential biosecurity issues of fresh feeds highlight the importance of developing manufactured feeds for lobster aquaculture. Wild lobsters are assumed to have a balanced natural diet that allows for standard growth and development, and as such natural diets are often used as a reference for feed development. Similarly, the gut microbiota associated with a natural diet is assumed to reflect a healthy microbial assemblage. The aim of this study was to compare the microbiota of the hindgut and hepatopancreas of cultured P. ornatus fed with a commercial prawn pellet or mussel to that of wild spiny lobster juveniles. Gut samples were analysed using Oxford Nanopore 16S rRNA gene sequencing. Based on principal coordinate analysis, the gut bacteria of cultured lobsters were different from the wild juveniles. The core microbiota of the hindgut and hepatopancreas libraries were phyla Proteobacteria (Gamma, Alpha) and Bacteroidetes. Vibrio was the most dominant genus in both organs. The differences in bacterial relative abundance were mainly between cultured (pellet-, mussel-fed) and wild lobsters. In conclusion, bacteria in the cultured lobsters had significantly different profiles to that of the wild juveniles, indicating that current onshore aquaculture practices alter the gut microbiota. A number of different feeding and culture practices may be required if the aim of closed culture practices is to attain a gut microbiota in cultured animals that is representative of that found in wild spiny lobsters.

5-Aminolaevulinic acid reduced the mortality of the Pacific white shrimp Litopenaeus vannamei infected with Enterocytozoon hepatopenaei

Hepatopancreatic microsporidiosis, the shrimp disease caused by Enterocytozoon hepatopenaei (EHP) infection, has been widely spread in farmed Litopenaeus vannamei in Thailand. The symptoms include decreased feeding, muscle waste, slow growth, and chronic mortality. Since 5-aminolaevulinic acid (5-ALA), a non-protein amino acid, has been known to enhance ATP production in the cell through the increased formation of hemoproteins in the electron transport complex of mitochondria, it was hypothesized that providing 5-ALA to EHP-infected shrimp might reduce the mortality caused by the infection. Naturally EHP-infected L. vannamei were randomly sampled from a commercial shrimp pond that showed signs of hepatopancreatic microsporidiosis. The shrimp samples were reared under 30-ppt seawater in 40-L plastic tanks, divided into four groups; each receiving commercial pellets supplemented with different doses of 5-ALA: 0 (control), 15, 30, and 60 ppm. After 21 days of the experiment, it was found that the shrimp receiving 5-ALA at 60 ppm survived at a rate significantly (p < 0.05) higher than that of other groups, and had a significant increase in biomass, compared with that of the control group. Histology of the hepatopancreas of the 60-ppm group revealed significantly (p < 0.01) less percentage of atrophic tubules and larger areas of the vacuoles of the B-cells, suggesting improved hepatopancreatic functions. The levels of the EHP load in the hepatopancreas as revealed by semi-quantitative PCR were increasing in a dose-related manner of 5-ALA supplement. Histology of the hepatopancreas also revealed the presence of EHP. The ATP levels in the hepatopancreas of the 30- and 60-ppm groups were significantly (p < 0.01) higher than that of the control group. Further tests are required in commercial farms to find out if the 5-ALA supplement is beneficial to tackle the problem of hepatopancreatic microsporidiosis at the industrial level.

Effects of immunocastration and supplementary feeding level on the performance and blood biochemical markers of farmed yearling fallow deer (Dama dama).

In cervids, blood biochemical markers may reflect changes in various physiological and environmental factors, especially in response to changes in metabolism following nutrient supplementation or the manipulation of hormone production. Decreasing androgen production through immunocastration (IC) to ease the husbandry of male animals is currently a more ethically acceptable method than physical castration, but its commercial use is unexplored in fallow deer. Forty yearlings male fallow deer were grouped into four treatment combinations: IC on high (200 g commercial pellets + 600 g concentrate mixture of 90% oats and 10% wheat grains) or low (100 g commercial pellets + 300 g concentrate mixture of 90% oats and 10% wheat grains) level of feed supplementation, or noncastrated bucks on a high or low level of feed supplementation. Immunocastrated animals were vaccinated at the start of the study (Week 1) and again during Week 3 of the study. Diet affected all body growth parameters (slaughter weight, daily gain, carcass weight, dressing percentageand body condition score). Fallow deer from all treatments showed increasing concentrations of fat and energy blood biochemical markers over the study period, including plasma glucose(GLU)and triglyceride(TRIG), and decreased cholesterol(CHOL) and lipase(LIPA) concentrations. The higher level of supplementary feeding decreased plasma albumin(ALB) and creatinine (CREA), and increased globulin(GLOB) concentrations. On the other hand, IC and lower-level supplementation reduced growth performance. Overall, IC may be an interesting tool for welfare management of yearling stags for slaughter; however, the advantage appears to only be in well-fed animals, as low-level of feeding can further reduce growth performance in immunocastrated animals. Further studies should evaluate the carcass performance of animals under similar treatment conditions to ascertain the effects on muscle and fat yields.

FISH FARMING PRACTICES AND DISEASE OCCURRENCE IN THE FISH FARMS OF DHANUSHA DISTRICT, NEPAL

Dhanusha is one of the leading fish producing districts in Nepal and the fish farming is increasing in the district to establish the district as a ‘Fisheries center’. However, with the increasing fish farming and intensity, a number of diseases find their way to the farm which may hinder the progress of fish farming. Present study was carried out to assess the fish farming practices and the disease occurrence across the fish farms of Dhanusha district. Questionnaire-based personal interviews were conducted with 64-fish farmers selected from all over the district using simple random sampling. Majority of the respondents were males (89.1%), in the active age group of 30-50 years (71.9%), with average experience of more than 15 years (39%) in fish farming. The widely adopted farming system was Carp polyculture, however, some of the farmers also culture other species like Pangas, African catfish, Rupchand, Puntius etc. Only earthen ponds were common with water depths of 5-7 ft (54.7%). Majority of the respondents relied on private hatcheries (34.4%) for fish seeds and the most common stocking size was fingerlings (42.2%) and fry (29.7%). The major source of information and technical support for the farmers were successful farmers (82.8%) and government offices (73.4%). Approximately 65.6% of the farmers had received trainings on fish production and disease management. The most common feed materials were mustard oil cake (100%); rice bran (96.9%) and commercial pellet feed (54.7%). Cattle dung (87.5%); poultry manure (28.1%) and Urea/DAP (95.3%) were the major fertilizers used by the farmers. The most prevalent fish disease was Argulosis (96.9%), Lernaea (90.6%) and EUS (85.9%), but asphyxiation (82.8%) caused the reportedly highest mortality of 346.1±305.5 Kg/ha. Similarly, the most susceptible species to disease was Naini (65.6%) followed by silver carp (49.0%) and bighead carp (34.0%), while the least infected species was Grass carp (0.8%). Winter (70.3%) was reported to be the main season for the occurrence of fish diseases in Dhanusha district. The average B/C ratio in pond aquaculture in the study area was 1.36.

Growth performance of hatchery-reared mahseer (Tor soro) based on different cultural periods

This study was carried out to evaluate growth performance, length-weight relationship, and condition factors of mahseer based on different culture stages. Fish larvae were produced by artificial spawning and reared in indoor tanks. Fingerlings were stocked in three replicate concrete ponds, fed with commercial pellets, and sampled within 4, 6, 12, and 24 months. In the first six months, the growth of fish increased much slower than in the 12 and 24 months of cultures. There were no significant differences in total weight at six months of culture (p&gt;0.05) compared with two and four months. Fish started to grow significantly different from 12 and 24 months of culture periods (P&lt;0.05). The specific growth rate in the four-month culture was 2.01±0.40 (%) and slightly increased in six-month culture periods (2.10±0.22%), but it started to decrease with increasing the day of culture (12 months : 1.58±0.09% and 24 months: 1.13±0.04%). Negative allometric trends (b&lt;3) were implied for all stages, but a high correlation occurred in the 12 and 24-month rearing periods with the equation W=0.331×L1.527 and W=0.375×L1.332, respectively. The condition factor ranged from 0.99 to 1.04, indicating fish tend to be poor, long, and thin.

Small wood pellet boiler 3-D CFD study for improved flue gas emissions employing flue gas recirculation and air staging

Wood biomass fuels have become increasingly important in terms of achieving future sustainability targets regarding RES, especially to reduce GHG and the use of domestic energy sources, on other hand with these fuels the pulutant air emissions have to be addressed with great attention. Nowadays, air staging and flue gas recirculation are often used as a primary emission reduction measure in large scale biomass fuel fired boilers, but their combined application in small scale commercial wood pellet boilers is not so common. The implementation of this approach to the small scale burning devices can enable further development of small boilers, in order to achieve a more complete combustion and reduction of pollutant emissions, especially CO, NOx, and PM. In the presented work a comprehensive numerical and experimental study on the combustion parameters is performed, in order to determine the overall combustion properties. A commercial 32 kW small-scale hot water wood pellet boiler was modified numerically from the operating point of view. The findings of this study, like different combinations of recirculated flue gases and secondary air amount, can serve as useful guidelines for the new innovative design and optimisation of the air and recirculated flue gas injection process parameters. The scenarios of this study, where recirculated flue gas was added to the secondary air, were beneficial. Optimally, a CO reduction of 63% was achieved by adding 30% of recirculated flue gas to the secondary air stream, and a 22% reduction was achieved for the NO emissions.

Can Azolla filiculoides be a complementary feed resource for ecological intensification in small-scale fish farming? Biological effects on giant gourami (Osphronemus goramy)

Using Azolla filiculoides, a candidate macrophyte species for ecological intensification, in small-scale aquaculture requires the investigation of the potential effects of fresh plant material not only on fish growth but also on physiological status and responses to disease and stress. In this study, juveniles of giant gourami Osphronemus goramy reared into cages placed in an outdoor pond were fed for six weeks with different proportions of fresh Azolla in replacement of commercial pellets (A: 100%, B: 56%, C:26% and D: 0% of the feeding events). The condition factor (KFulton) somatic and immunological indicators were measured. Effects of Azolla on transport stress and bacterial infection with Aeromonas hydrophila were also assessed. Results showed that KFulton decreased with increasing proportions of Azolla in the diet (p &lt; 0.001). Total protein, albumin and globulin in fish from treatment A were significantly lower than in the other treatments. A decrease in lymphocytes was observed in treatments A and B (p &lt; 0.001) and fish from these treatments had higher levels of monocytes (p &lt; 0.001). Neutrophils were higher in treatment A only (p = 0.012). Plasma lysozyme levels and serum bactericidal activity increased with Azolla in the diet (both p &lt; 0.001). Before transport stress, glycaemia was lower in fish from treatment A (p &lt; 0.001) while after transport, glycaemia increased in all treatments excepted treatment A (p &lt; 0.001) where survival was the highest after 15 days post transport. One week after infection the survival of fish was higher in fish from treatments A and B (p &lt; 0.001). Azolla had positive effects on immunological indicators, and resistance to stress and disease but decreased growth. These findings suggest using Azolla at reasonable rate (i.e. &lt;30% of the diet) to reduce pellets inputs while maintaining growth and providing other benefits to fish.

Production and Characterization of Andong Bamboo (Gigantochloa pseudoarundinacea (Steudel) Widjaja) Pellets from Various Stem Parts

Bamboo is an abundant biomaterial having important potential as a resource for bioenergy development. In this study, the potential of andong (Gigantochloa pseudoarundinacea (Steudel) Widjaja) bamboo for pellet production was evaluated. Some properties of bamboo pellets as density, moisture content, moisture adsorption, compressive strength, and heating value were analysed. The results indicated that bamboo is highly prospective to be explored for fuel pellets commercially. All characteristics of pellet made of bamboo fulfilled the requisites of the commercial pellets. The heating value of the pellets achieved the minimum standard for commercial pellets along with SNI 8675:2018 (&gt;17,5 MJ/kg). The effects of culm parts on the moisture content, density, moisture adsorption were not significant. There were significant differences in compressive strength and heating value between bamboo pellets produced from different culm parts. This research showed potential of andong bamboo pellet for bioenergy resource. Keywords: Andong (Gigantochloa pseudoarundinacea), Biopellet, Mechanical Properties, Physical Properties

Field Efficacy of a Feed-Based Inactivated Vaccine against Vibriosis in Cage-Cultured Asian Seabass, Lates calcarifer, in Malaysia.

Vibrio spp. are important aquaculture pathogens that cause vibriosis, affecting large numbers of marine fish species. This study determines the field efficacy of a feed-based inactivated vaccine against vibriosis in cage-cultured Asian seabass. A total of 4800 Asian seabass, kept in a field environment, were separated equally into two groups (vaccinated and non-vaccinated) in duplicate. Fish of Group 1 were orally administered the feed-based vaccine on weeks 0 (prime vaccination), 2 (booster), and 6 (second booster) at 4% body weight, while the non-vaccinated fish of Group 2 were fed with a commercial formulated pellet without the vaccine. Fish gut, mucus, and serum were collected, the length and weight of the fish were noted, while the mortality was recorded at 2-week intervals for a period of 16 weeks. The non-specific lysozyme activities were significantly (p &lt; 0.05) higher in the fish of Group 1 than the non-vaccinated fish of Group 2. Similarly, the specific IgM antibody levels in serum and mucus were significantly (p &lt; 0.05) higher in Group 1 than in Group 2, as seen in the second week, with the highest level 8 weeks after primary immunization. At week 16, the growth performance was significantly (p &lt; 0.05) better in Group 1 and showed lower bacterial isolation in the gut than Group 2. Despite the statistical insignificance (p &gt; 0.05), the survival rate was slightly higher in Group 1 (71.3%) than Group 2 (67.7%). This study revealed that feed-based vaccination improves growth performance, stimulates innate and adaptive immune responses, and increases protection of cultured Asian seabass, L. calcarifer, against vibriosis.