Fish Feed Research Articles

The impact of extension delivery through private local service providers on production outcomes of small-scale aquaculture farmers in Bangladesh

ABSTRACT Purpose This study delves into the effectiveness of local service providers (LSP) in improving production outcomes of small-scale aquaculture farmers in Bangladesh. Design/methodology/approach To gauge the effectiveness of LSPs, the research employs a performance-based assessment approach, focusing on 1653 fish farming households distributed across four different participation levels. Essentially, it compared quantifiable variables like the number of species cultured, productivity, proportion of fish sold and revenue metrics of the LSP-trained farmers against a control group that has not received training from LSPs. Data analysis was conducted with Multivalued Treatment Effects (MTE) estimated using an augmented inverse-probability weighting method that allows for heterogeneous treatment effects. Findings Findings revealed that farmers who received the LSP extension training exhibited a significant increase in all outcomes compared to their counterparts. The LSP extension participating farmers are more likely to adopt better management practices like improved feeding routines, dike constructions, pond cleanliness, and fish growth monitoring. Practical implications LSP extension model with enhanced capacity can be a catalyst for improved production of small-scale aquaculture farmers. Theoretical implications This study contributes to a research agenda related to the efficiency of emerging pluralistic extension service systems that favors decentralization, privatization, and outsourcing of extension service, and their capability to enhance the production outcomes of small-scale farmers. Originality/value This study addresses an important research gap in the agricultural extension literature, which is the value-for-money of Local Service Providers, and their capability to enhance the production outcomes of small-scale farmers.

Microplastics contamination in commercial fish meal and feed: a major concern in the cultured organisms

The growing scale of plastic pollution causes a devastating impact on the aquatic ecosystem. The people largely depend on animal-based food for their protein requirements. In this study, we analysed 10 different fish meal samples and 20 feed samples used in farming to understand the level of microplastic (MPs) contamination and estimate the amount of MPs ingested by farmed fish, shrimp, and chicken through feed. The abundance of MPs in fish meal samples ranges from 210 ± 98.21 to 1154 ± 235.55 items/kg. The fish meal produced from dried fish is more prone to MPs contamination than that produced from fresh fish. In the case of fish feed, MP abundances range from 50 ± 22.36 to 160 ± 36.57 items/kg in shrimp feeds, 60 ± 26.74 to 230 ± 52.32 items/kg in fish feeds and 90 ± 25.11 to 330 ± 36.12 items/kg in chicken feeds. The exposure rate of MPs is higher in the grower- and finisher-stage feeds than in the starter feed. Fiber-shaped MPs of size 100–500 μm with PE and PP polymers were predominantly found in fish meal and feed samples. EDAX analysis showed the presence of Cr, Cd, Ti, Ni, Cu, As, Al, Pb, Hg, Cd, Ti, Fe, Ca, K, and Si in fish meal samples and Ca, Na, Zn, Cu, Ni, Cl, Al, Si, S, Pb, Cd, Ti, Cr, Mg and Fe in feed samples. The possible level of exposure of microplastic particles was calculated based on MP contamination in feed, feed consumption rate, and body weight. We estimated an MP exposure level of 531-1434 items/kg feed for farmed shrimp, 234–4480 items/kg feed for fishes, and 3519–434,280 items/kg feed for chicken. This study concludes that fish meal and feed are one of the important exposure routes of MPs to the farmed animals.

Carp growth, body composition, lipidomics, and flesh quality in response to replacing dietary fish meal with a complex protein source

Alternatives to fish meal (FM) in fish feed are urgently required in aquaculture. We therefore examined the effect of replacing FM with a complex protein source (CPS) comprising soybean meal, peanut meal, corn protein meal, feather meal, and yeast protein, on carp (Cyprinus carpio) growth, body composition, lipidomics, and flesh quality. Lipidomics analysis was conducted to reveal the impact of dietary changes on fish lipid composition and metabolism, which is closely related to flesh quality and nutritional value. Over an eight-week growth trial, fish meal was replaced with CPS at 0 % (FM only), 20 %, 40 %, 60 %, 80 %, or 100 %. Weight gain and other growth parameters did not differ significantly among the treatments. Lipid deposition (LD) was positively correlated, and protein deposition negatively correlated, with CPS levels. LD and fillet ether extract were significantly elevated at 100 % CPS, whereas superoxidase dismutase expression, claudin-1 expression, and lipase activity were significantly reduced. The n-3 PUFA level and n-3/n-6 PUFA ratio were significantly lower following CPS feeding, reducing flesh quality. These findings indicate that CPS successfully replaced 60–80 % of dietary FM in carp diets, while the 100 % replacement group provided insights into the comprehensive effects of total substitution. Future studies will further optimize formulations based on these results to resemble practical production more closely. CPS with nutrient supplementation may therefore present a viable and safe partial replacement for dietary FM.

Effect of pellet-size on fish growth, feeding behaviour and natural food web in pond polyculture

In carp-tilapia pond polyculture, carps are stocked once and usually harvested each 12 to 24 months, while, tilapia is stocked and harvested each 4 to 6 months. Therefore, per carp cycle there are 3 to 6 tilapia cycles. With time, carps grow bigger while tilapia reach only 10 to 50% the mass of carps. Pellet size can offer a feeding management tool in the ponds with large carp and small tilapia. This experiment investigated whether pellet-size can steer the growth of large carps (∼ 500 g) and small tilapias (∼30 g) in polyculture ponds. Four pellet-size treatments were applied in this study, each with a different combination of small (2 mm) and large (6 mm) pellets (on weight basis): S100L0 (100% small, 0% large), S50L50 (50% small, 50% large), S25L75 (25% small, 75% large) and S0L100 (0% small, 100% large). Each treatment was applied to six replicate ponds. The experiment lasted for 8 weeks. The treatments did not alter carp production, but tilapia production was highest in S100L0 treatment ponds (P < 0.001). The fish always needed more time to consume large pellets than the small pellets. Small pellets were consumed much quicker when the portion fed was small, indicating strong competition. A similar trend was observed with large pellets but the difference in feed intake time across the treatments was smaller than with small pellets. This is because tilapia ate the majority of both small and large pellets while carps ate less pellets. Tilapia at treatment S0L100 had a lower protein and fat content and a higher ash content than at the other pellet-size treatments. Carp's body composition remain unaffected by pellet-size treatment except the ash content of rohu which was highest at S100L0 and lowest at S0L100. By volume, tilapia had a higher amount of food in the stomach in treatments S100 L0 and S50L50 than in the other treatments. In contrast, more food was found in the gut of rohu in treatments S0L100 and S25L75 than in the other treatments. Pellet-size treatments did not affect water quality and the pond food web (P > 0.05) except phytoplankton diversity which was positively influenced when feeding more large pellets. The plankton population increased with the progression of the experiment, suggesting the food web was not fully exploited. In conclusion, pellet-size proves to be a feeding management tool to steer the production of tilapia as well as of total fish biomass, but not of carp's biomass in carp-tilapia pond polyculture.

Evaluation of Quality and Stability of Fish-vegetable Composite Bio-silage based Fish Feed Stored at Room Temperature

Evaluation of Quality and Stability of Fish-vegetable Composite Bio-silage based Fish Feed Stored at Room Temperature

Assessment of Encapsulated Probiotic Lactococcus lactis A12 Viability Using an In Vitro Digestion Model for Tilapia.

Probiotics face harsh conditions during their transit through the gastrointestinal tract (GIT) of fish because of low-pH environments and intestine fluid. Therefore, the evaluation of probiotic viability under simulated gastrointestinal conditions is an important step to consider for probiotic supplementation in fish feed prior to in vivo trials. Therefore, this study aimed to evaluate the effect of stomach and intestinal simulated conditions on the viability of encapsulated Lactococcus lactis A12 using an in vitro digestion model for tilapia. A Box Behnken design was used to evaluate the potential effect of three factors, namely stomach pH, residence time in the stomach, and enzyme quantity, on the viability of encapsulated Lactococcus lactis A12. As the main results, low pH (4.00), long residence time (4 h), and enzyme quantity (2.68 U of total protease activity) led to lower final cell counts after the phases of the stomach and intestine. Encapsulated probiotic bacteria showed higher viability (p < 0.05) and antibacterial activity (p < 0.05) against the pathogen Streptococcus agalactiae than non-encapsulated bacteria. The results suggest that L. lactis A12 survives in GIT conditions and that the proposed in vitro model could be used to explore the viability of probiotic bacteria intended for fish feed supplementation.

Tracing the journey of elements from fish feed to Nile tilapia faeces to black soldier fly larvae: a comparative approach

Tracing the journey of elements from fish feed to Nile tilapia faeces to black soldier fly larvae: a comparative approach

Biochemical Evaluation of Millet-Based Fish Feed and its Effect on Danio Rerio (Zebrafish) on its Growth Parameters

Biochemical Evaluation of Millet-Based Fish Feed and its Effect on Danio Rerio (Zebrafish) on its Growth Parameters

CFFI-Vit: Enhanced Vision Transformer for the Accurate Classification of Fish Feeding Intensity in Aquaculture

CFFI-Vit: Enhanced Vision Transformer for the Accurate Classification of Fish Feeding Intensity in Aquaculture

Overview on the role of dietary Spirulina platensis on immune responses against Edwardsiellosis among Oreochromis niloticus fish farms

Edwardsiellosis is a bacterial fish disease that mostly occurs in freshwater farms and is characterized by a high mortality rate. Edwardsiella tarda strain was recovered from 17 fish out of 50 Nile tilapia, which were harboring clinical signs of systemic septicemia. The level of un-ionized ammonia (NH3) in the fish farm’s water was 0.11–0.15 mg/L, which was stressful for the Nile tilapia.Sequencing of the gyrB1 gene confirmed that the isolate was E. tarda JALO4, and it was submitted to NCBI under the accession number PP449014. The isolated E. tarda harbored the virulence gene edw1 AHL-synthase (quorum sensing). In addition, the isolate was sensitive to trimethoprim and sulfamethoxazole mean while it was intermediate to florfenicol. The median lethal dose (LD50) of E. tarda JALO4 was determined to be 1.7 × 105 CFU/mL in Nile tilapia.In the indoor experiment, Nile tilapia (45.05 ± 0.4 g), which received dietary Spirulina platensis (5 and 10 g/kg fish feed), showed optimum growth and feed utilization. Meanwhile, after receiving dietary S. platensis, the fish’s feed conversion ratio (FCR) was significantly enhanced compared to the control, which was 1.94, 1.99, and 2.88, respectively. The expression of immune-related genes interleukin (IL)-1β and tumor necrosis factor (TNF)-α were upsurged in E. tarda-challenged fish with higher intensity in S. platensis groups. Dietary S. platensis at a dose of 10 g/kg fish feed could provide a relative protection level (RPL) of 22.2% Nile tilapia challenged against E. tarda. Nile tilapia experimentally infected E. tarda, drastically altering their behavior: higher operculum movement, low food apprehension, and abnormal swimming dietary S. platensis (10 g/kg fish feed) could rapidly restore normal status.It was concluded that Edwardsiellosis could alter Nile tilapia behavior with a high loss in fish population. Fish received dietary-S. platensis could rapidly restore normal behavior after E. tarda infection. It is recommended the incorporation of S. platensis at doses of 10 g/kg into the Nile tilapia diet to boost their immunity and counteract E. tarda infection.

Suction Feeding Turned on Its Head: A Functional Novelty Facilitates Lower Jaw Protrusion.

Functional novelties play important roles in creating new ways for organisms to access resources. In fishes, jaw protrusion has been attributed to the massive diversity of suction-based feeding systems, facilitating the dominant mode of prey capture in this group. Nearly all fishes that feed by suction use upper jaw protrusion, achieved by rotation of the mandible at its base, which then transmits forward motion to independently mobile upper jaw bones. In this study, by contrast, we explore an unusual form of lower jaw protrusion in the freshwater invertivore, Nannocharax fasciatus, enabled by a novel intramandibular joint (IMJ). We combine morphological, kinematic, and biomechanical data to show that the added mobility created by the IMJ influences the pattern of suction-based prey capture movements and contributes to lower jaw protrusion (increasing it by 25%, based on biomechanical modeling). Interestingly, the upper jaw bones are fused in N. fasciatus and rotate about a single fixed joint, like the lower jaws of most other suction feeding fishes. We suggest that this vertical inversion of the jaw protrusion mechanism for ventrally directed suction-feeding on benthic prey is a likely exaptation, as the IMJ is used for biting in related taxa. This work highlights the ability of novelties to facilitate ecological specialization by enabling new functional capabilities.

A question of digestion: How microalgae species affects lipid and fatty acid digestibility in rainbow trout (Oncorhynchus mykiss)

Alternative nutrient sources for fish feed are currently of high interest. Feed ingredients with suitable lipid contents and valuable amounts of essential fatty acids are especially needed to relieve the usage of fish oil and maintain high product quality of fish from aquaculture. Microalgae contain promising nutrient contents and suitable fatty acid profiles that cover dietary requirements of fish. Nutrient digestibility, however, can be hindered by their rigid cell wall. Therefore, in the presented study, the microalgae species Isochrysis galbana and Tetraselmis chui were processed by freeze-drying and centrifugal milling to evaluate their nutrient and fatty acid digestibility in fish nutrition. For T. chui, an additional treatment with enzyme supplementation was tested. Test diets contained 70% of a fish meal based reference diet and 30% of the respective microalgae meal, as well as titanium dioxide as an inert marker to calculate apparent digestibility coefficients (ADC). Rainbow trout (Oncorhynchus mykiss) were fed for 14 days and faeces were collected via manual stripping. The ADCs of Kjeldahl nitrogen (∼ 64–79%), nitrogen-free extracts (∼ 40–54%) and energy (∼ 52–66%) were not significantly different between the algae species, but I. galbana inclusion resulted in reduced lipid digestibility (∼ 57% to 77%), which was linked to the high content of saturated fatty acids. The fatty acid ADCs were higher for T. chui except for arachidonic acid (20:4 n-6) and lauric acid (12:0). Mechanical or enzyme-treating processing did not increase nutrient and fatty acid digestibility for the microalgae used in this trial, and sole freeze-drying sufficiently ensured nutrient availability. The high digestibility of nutrients and, particularly, polyunsaturated fatty acids of I. galbana and T. chui underscore their potential as fatty acid and nutrient sources in fish feed.

Polyculture of Genetically Improved Farmed Tilapia (GIF tilapia) and Penaeus vannamei Using Biofloc Technology – A Review

According to Food and Agriculture Organization of the United Nations (FAO), aquaculture has grown faster and its expansion aimed at meeting the increase of world fish demand, and preserving natural fish stocks. Currently, to produce fish in quantity and quality requires reduction of the environmental impact from aquaculture, through the improvement of culture systems. Disease is the major factor affecting the development and expansion in aquaculture. Losses due to disease in shrimp farming are high. Various approaches to minimize the impact of disease on production are possible. Another approach to keep the pathogen pressure low is polyculture of shrimp and finfish. This practice makes shrimp farming more sustainable by reducing the environmental impact and the incidence of shrimp disease. Antimicrobial peptides in the fish skin kill shrimp pathogens, keeping pathogen pressure of bacteria and viruses low. In polyculture, shrimps can eat tilapia faeces and unused fish feed, while tilapia filter phytoplankton, reducing the risk of low dissolved oxygen levels at night. In addition, shrimp bioturbation at the pond bottom returns nutrients to the water column, enhancing phytoplankton production and consequently the natural feed available for the tilapia. Biofloc technology (BFT) is one of the most applicable and promising systems for sustainable aquaculture development. This technology is essentially based on the recycling of nutrients via microorganisms, primarily (i) heterotrophic bacteria, which convert nitrogen compounds into microbial biomass, in addition to serves as a source of food for aquatic organisms, and (ii) chemoautotrophic bacteria, which convert ammonia to nitrite and nitrate.

Plankton and benthos in Lake Blagodatnoye (Iturup Island) in summer

Lake Blagodatnoye is an oligohaline meromictic reservoir with the two-layer vertical structure — a typical lagoon lake for the southern Far East of Russia. Its upper layer is occupied by fresh water and the lower layer — by brackish water. The greatest warming of water (up to 22 оC) is observed at the lake surface in late July — early August. In total, 274 species are found in phytoplankton of the lake that is the largest number among all surveyed lagoon lakes in the south of Sakhalin-Kuril region. Bacillariophyta form the basis of the phytoplankton species composition (64 % of species). Abundance and biomass of the phytoplankton vary widely from 1.15 . 106 to 160.44 . 106 cells/L and from 0.41 to 6.14 g/m3, respectively. Several peaks are noted in seasonal dynamics of these indices. Zooplankton in the lake includes 25 species. All these species are typical for lagoon lakes in the south of Sakhalin-Kuril region. Wide variations in abundance and biomass are noted for the zooplankton: from 10550 to 99350 ind./m3 and from 47.1 to 231.0 mg/m3, respectively. Two types of species composition are identified in the summer succession of the phytoand zooplankton communities. The phytoplankton groups change at the border between June and July, when temperature at the surface passes the value of 14–16 оC. The key species of the early-summer phytoplankton are Cyanobacteria of genera Aphanocapsa, Chroococcus, Microcystis, Anabaena and Bacillariophyta of the genus Asterionella, whereas Aulacoseira granulata and A. granulata var. angutissima are the most abundant in late summer. For zooplankton, the boundary between the early-summer and late-summer seasons is shifted to middle July when the water temperature rises to 17–18 оC. Rotifera of Asplanchna priodonta, Cladocera of Bosmina sp., younger copepodites of Cyclops and Eurytemora caspica tethysiana dominate in early summer, whereas Bosmina sp. and juveniles of Cyclops — in late summer. Macrozoobenthos in the lake is represented by 25 species of invertebrates. The basis of species diversity is formed by amphibiotic insects. Number of species and total distribution density and biomass of macrozoobenthos mostly declined with the depth: there were 18 species, 370 ± 50 ind./m2, 3.023 ± 0.459 g/m2 in the intertidal zone, 14 species, 580 ± 59 ind./m2, 3.477 ± 0.447 g/m2 in the elittoral zone, and 10 species, 364 ± 36 ind./m2, 2.110 ± 0.248 g/m2 in the profundal zone, and dominant species were changed from Amphipoda Eogammarus barbatus in the intertidal zone to Chironomidae Chironomus dorsalis in the elittoral zone and to Gastropoda Cincinna japonica, Oligochaeta Lumbriculus variegatus and Chironomidae C. dorsalis in the profundal zone. The phytoplankton production in the coastal zone (depth of 0–3 m) was estimated as 552.86 kcal/m2 in June-August. Zooplankton consumed only 0.7 % of this production and produced 767 cal/m2. The production of non-predatory zoobenthos was 8644 cal/m2, with the inputs of 70.2 % for detritus feeders of 70.2 %, 11.8 % for macroalgae feeders, 11.6 % for deposit feeders, 5.8 % for grazers, and 0.6 % for filtered suspension feeders. A part of this production (6.9 %) was transmitted to the feed of carnivorous zoobenthos, so 8286 cal/m2 of the macrozoobenthos production could be used for fish feeding in the coastal zone. The phytoplankton production in the open waters (depth of 3–9 m) was estimated in 2580 kcal/m2. Zooplankton consumed 1.01 % of this production and produced 3578 cal/m2. The production of non-predatory zoobenthos in this zone was 6179 cal/m2 (detritus feeders 68.1 %, deposit feeders 18.8 %, grazers 6.6 %, macroalgae feeders 3.0 %, and filtered suspension feeders 3.5 %). The portion of 12.7 % of this production was transmitted to the feed of carnivorous zoobenthos. The total macrozoobenthos production in the open waters was 5708 cal/m2. The total reserve of food for fish, including zooplankton and benthos, was evaluated in 9286 cal/m2.

Sponges as feeding resource for the white seabream Diplodus sargus (Linnaeus, 1758) from the Mediterranean Sea

Sponges play a significant role in many marine environments. In tropical regions, the relationship between Porifera and spongivorous organisms, including fish, has been extensively studied. In the Mediterranean Sea, the dominant predators of sponges are sea stars, sea urchins and nudibranches, while knowledge of fish feeding on sponges is limited to sporadic events. This study aimed to investigate sponges as part of the diet of the white seabream Diplodus sargus. The results revealed that sponges were abundantly present in seabream stomachs, reaching up to 79.7% of the total biomass ingested by a single individual. Five different species were found in fish stomachs. The presence and organization of the spicular component seemed to affect the biting strategy of fish. Sponges with a prevalent organic component, such as Chondrosia reniformis Nardo, 1847, and Chondrilla nucula Schmidt, 1862, were ingested as fragments, while specimens of the Tethya citrina Sarà & Melone, 1965, characterized by a globular body, were engulfed entirely. Data from this study represent the first effort to investigate the trophic relationship between fish and Porifera in the Mediterranean Sea.

Optimizing winged-bean meal through oven and autoclave heating as viable alternative for plant-based aquafeed

Winged-bean meal can serve as a substitute for soybean meal in plant-based fish feed, despite its trypsin-inhibitor properties, which can be alleviated through heating processes. This study aimed to explore the potential of winged-bean meal subjected to different heating methods, namely oven (110 °C for 30 minutes) and autoclave (121 °C for 30 minutes), based on proximate analysis and trypsin activity. The study applied three treatments with four replications: oven heating (O), autoclave heating (A), and control (without heating, E). All data were analyzed using analysis of variance and Duncan’s multiple range test to determine the best treatment. Data were also compared to the nutrient requirements of several cultured freshwater fish in Indonesia. Heating treatments improved in vitro trypsin activity (1300 units/O and 1135 units/A vs. 835 units) but reduced protein (29.05±1.96%/A and 31.73±1.52%/O vs. 35.17±0.38%) and moisture contents. Additionally, the O treatment met the standards for aquafeed protein content (27-45%) and potentially fulfilled the protein requirements for catfish (25-40%), Nile tilapia (30-35%), and Java barb (30-32%). Therefore, oven heating presents a viable candidate as an alternative plant-based aquafeed ingredient. Nevertheless, the in vivo application of winged-bean meal as an aquafeed ingredient should be further evaluated to determine whether heating treatment effectively enhances digestive activity, nutrient retention, and growth performance in target fish species.

Heavy Metal Concentrations in Water, Sediment, and Fish Species in Chashma Barrage, Indus River: A Comprehensive Health Risk Assessment.

The increasing levels of heavy metals in aquatic environments, driven by human activities, pose a critical threat to ecosystems' overall health and sustainability. This study investigates the bioaccumulation of heavy metals (Pb, Cu, Cr, and Cd) in water, sediment, and three fish species (Catla catla, Labeo rohita, Cirrhinus mrigala) of different feeding zones within Chashma Barrage, located in the Mianwali district of Punjab, Pakistan, on the Indus River. A comprehensive analysis, including an assessment of associated human health risks, was conducted. Thirty samples from all three sites for each fish species, with an average body weight of 160 ± 32g, were collected from Chashma Barrage. Water quality parameters indicated suitability for fish growth and health. Heavy metal concentrations were determined using an atomic absorption spectrometer. Results indicated elevated levels of Cd, Cr, and Cu in sediment and Pb and Cd in water, surpassing WHO standard limits. Among the fish species, bottom feeder (C. mrigala) exhibited significantly (P < 0.05) higher heavy metal levels in its tissues (gills, liver, and muscle) compared to column feeder (L. rohita) and surface feeder (C. catla). Liver tissues across all species showed higher heavy metal bioaccumulation, followed by gills. Principal component analysis (PCA) revealed strong correlations among heavy metals in sediment, gills, muscle, and water in every fish species. However, the vector direction suggests that Cr was not correlated with other heavy metals in the system, indicating a different source. The human health risk analysis revealed lower EDI, THQ, and HI values (< 1) for the fish species, indicating no adverse health effects for the exposed population. The study emphasizes the bioaccumulation differences among fish species, underscoring the higher heavy metal concentrations in bottom feeder fish within Chashma Barrage.

Fish Feeding: Utilization of Rice Washing Water (RWW) and Fermented Citrus Peel (FCP) as culture Media for Bloodworms (Chironomus spp.)

Bloodworms are a most common and significant food source for freshwater fish, and they are also used as lures for fishing. Rice washing water accommodates important soluble nutrients. Fermented Citrus Peel is also a magnificent source of nutrients. On a daily basis, we let go of numerous wastes that can be utilised for cost-effective culturing. A possible solution is to use (RWW) &amp; (FCP) waste as nourishing sources for Bloodworms. The aim of this study was to estimate the better growth of Bloodworms that were fed with different concentrations of Rice Washing Water (RWW) and Fermented Citrus Peel (FCP). Analysis of variance and least significance difference were used as data analytics. The design for analysis obtained was testing with five treatments and three replicates. C1 = 0% rice wash water, 100% fermented citrus peel; C2 = 25% rice wash water, 75% fermented citrus peel; C3 = 50% rice wash water, 50% fermented citrus peel; C4 = 75% rice wash water, 25% fermented citrus peel; and C5 = 100% rice wash water, 0% fermented citrus peel. Altogether, the water quality lies in a temperature range of 23–28 °C, and a pH value of 6.5-8 implies an ideal environment for the growth of bloodworms. According to the results, treatment C3 showed the highest population density and growth rate.

Effects of dietary Pediocuccus pentosaceus and/or ferulic acid on performance, digestive enzymes, blood biochemistry, and growth-related genes expression in rainbow trout (Oncorhynchus mykiss)

This study investigated the effects of dietary Pediocuccus pentosaceus (PP) and/or ferulic acid (FA) on the performance, digestive enzymes, and growth-related genes expression in rainbow trout (Oncorhynchus mykiss). Fish (94.30 ± 1.77 g) were fed on the control diet (T0), 108 CFU/g of PP probiotic (T1), 100 mg/kg of FA (T2), and a combination of PP and FA (T3) for 8 weeks. The present results indicated that rainbow trout fed with PP and/or FA showed better final weight, weight gain, and feed conversion ratio than the control group (P < 0.05). The activities of trypsin and chymotrypsin were higher in T2 and T3 than in the control group (P < 0.05). Meanwhile activities protease and alpha-amylase were highest in T2, lipase activity was highest in T3. Compared to the control group, total protein, total antioxidant activity, and cholesterol levels were significantly (P < 0.05) higher in T2 and T3 with no significant (P > 0.05) differences between them. Supplemented diets with FA and/or PP decreased markedly (P < 0.05) triglycerides levels and its lowest levels were obtained in T2 and T3 with no significant (P > 0.05) differences between them. The relative expression levels of GHRL and GHr genes were significantly higher in the treatments fed with FA and/or PP (T1 – T3) than those in the control group (P < 0.05). Highest upregulation of IGF-1, and IGF-II gens were detected in T2 and T3 with no significant (P > 0.05) differences between them. In conclusion, it was shown that both dietary supplements have the potential role to enhance the performance, digestive enzymes, and growth related-genes expression in rainbow trout. Feeding fish on FA-enriched diets showed superior enhancements than that fed on the PP diet only.

Rancang Bangun Alat Penebar Pakan Ikan dengan Menggunakan Gaya Sentrifugal Tipe Apung

Cultivated in industrial scale and also household scale. One of the supporting component of catfish cultivation is a fish feeding tool that applicated. The problem of the tool was the uneven distribution of fish feed according to the pool area. The redesign of fish feeding tool was a solution to overcome the problem. This study aimed at designed, maked, and tested the fish feeding tool using centrifugal force of floating type. The research method started from sketched the tool based on predetermined measures before process of making the tool. The making of the tool produces a prototype of fish feeding tool using centrifugal force of floating type of whole dimension 80 cm long, 43 cm wide and 80 cm high. This fish feeding tool can spreaded 2 size of fish feed (2-2.3 mm and 3.2-4 mm diameter). The next process was testing the tool with 3 times repetition. The results of this research was this fish feeding tool can spreads the feeds uniformly at the distance of 500 cm to 700 cm for LP 781-1 fish feed type and the distance of 700 cm to 1000 cm for LP 781-3 fish feed type. The capacity of fish feeding tool has feeding capacity of 136.1 kg / hour for LP 781-1 fish feed type and 129.6 kg / hour for LP 781-3 fish feed type. Keywords: Centrifugal, Feed Spreader, Fish Feed, Floating Type.