Fish Silage Research Articles

Zootechnical Performance, Protease Activity and Proximate Composition of Nile Tilapia Fed Diets Containing Fish Silage Produced from Fish Waste

The present study was carried out to evaluate the impact of fish silage (FS) on the growth performances, protease enzyme activity and muscle compositions of Nile tilapia. In this regard, FS was produced from the waste parts of carp, pangus and tilapia and five iso-nitrogenous (containing 35% crude protein) diets were formulated in which fishmeal (FM) was used as the primary protein source in the control diet (0% FS, T1). The remaining four diets were formulated by replacing 25% (T2), 50% (T3), 75% (T4), and 100% (T5) FM protein with the FS. These diets were fed to tilapia at 8-6% of their body weight rearing them in glass tanks at the density of 15 fish/tank in triplicates. After fifty-days feeding trial, survival (%) of fish remained unaffected among the dietary treatments. Tilapia fed with 75% FS based diet showed improved growth and lower FCR, whereas those fed a diet with 100% FS exhibited lower growth rates. Notably, protease enzyme activity (mg/ml/min) increased with higher levels of FS inclusion. Increased crude protein content was observed in the fish fed the 75% FS diet. These findings underscore the potential of including FS up to 75% to enhance the growth performance of Nile tilapia.

Exploring Sustainable Aquafeed Alternatives with a Specific Focus on the Ensilaging Technology of Fish Waste

The global increase in population has placed significant pressure on food security, leading to the emergence of aquaculture as a vital source of aquatic foods. However, rising costs and limited fish meal availability in aquafeeds have driven the search for alternative protein sources. While plant-based ingredients have been integrated into commercial aquafeeds, they come with challenges such as low protein content, palatability issues, and the presence of antinutritional factors. In this context, fish silage, made from fish waste and discarded fish, stands out as a promising alternative technology due to its cost-effectiveness and sustainability attributes. The production of fish silage involves the addition of organic/inorganic acids or lactic acid bacteria to homogenized fish waste, yielding a valuable mixture rich in peptides and free amino acids, offering significant nutritional benefits for animal diets. This review aims to promote sustainable practices in the aquaculture industry by analyzing research results related to ensiling technology, appraising the advantages and disadvantages of using fish silage as a feed ingredient, and focusing on emerging trends in this field.

To Standardise Parameters for Preparation of Extruded Feed Using Various Conventional and Non-Conventional Ingredients

The purpose of this research was to optimise extruder parameters for the preparation of floating fish diets with appropriate physicochemical qualities. The impact of temperature (90-120oC), moisture content (15%-30%), die diameter (2.0-4.0 mm) and pre-conditioning duration (15-30 m) on physical properties of the pellets such as bulk density, floatability, expansion ratio and water stability, were examined. Accordingly, four iso-nitrogenous (crude protein 35%) experimental diets were formulated for GIFT tilapia advance fry by replacing 50% of GNOC protein of the control diet (T0) by sunflower oilcake (SFOC) (T1), by linseed oilcake (LSOC) (T2) and by fish based silage (T3) protein. The pellets extruded using a combination of 120 oC extruder barrel temperature, 25% moisture content of feed mix, 2.0 mm die diameter and 30 minute of pre-conditioning duration gave most required pellet floatability (90-100%), expansion ratio (1.43-1.61), water stability (95-99%) and bulk density (0.8 - 0.9 g/cm3) for T1 and T2. However, fish silage when incorporated in the feed mix, it affected negatively in all the physical characteristics of a floating feed and resulted in higher bulk density and lower floatability, expansion ratio and also water stability.

Evaluation of Nutritional Content of Fermented Fish Visceral Silage using Sorbic Acid and Effective Microorganism (EM4)

Fish silage is a liquid product produced from whole or part of a fish processed by fermentation utilizing the activity of enzymes produced by microba. The fermentation process can be carried out chemically or biological. The purpose of this research is to determine the nutritional content of fish silage fermented using Sorbic Acid and EM4. This research uses an experimental method by mixing cleaned fish with 3% Sorbic Acid and 20% EM4. The highest protein content is found in fish silage fermented with Sorbic Acid, that is 55.05% followed by fat and carbohydrate content of 22.01% and 19.61%. Meanwhile the protein content of fish silage fermented with EM4 is 26.55%. Research results show that fish silage fermented with Sorbic Acid has the best performance by increasing the protein content of the silage.

Molecular weights and optimum temperature and pH for pepsin activity of three sciaenid finfish species from the Gulf of California

By-products from finfish processing from fisheries and aquaculture are often discarded. However, the enzymatic content of viscera has potential biotechnological and industrial applications. Such is the case for the sciaenids Cynoscion othonopterus, Cynoscion xanthulus, and Cynoscion parvipinnis, which are food and game fishes from the Gulf of California and whose viscera are commonly discarded after fish dressing. In this study, optimum temperature and pH for activity, as well as molecular weights of pepsin from the stomach of C. othonopterus, C. xanthulus, and C. parvipinnis were evaluated for the first time. Pepsin molecular weights were 30, 32.1, and 32.3 kDa, respectively. The highest activity of pepsin against hemoglobin was recorded between 40 and 45?C for C. othonopterus and C. xanthulus and at 40?C for C. parvipinnis. The optimum pH was 2.0 for the three sciaenids. Biochemical characteristics were comparable to pepsins from other marine and freshwater fish species, so they could likely be used in some processes using this enzyme, like collagen extraction, fish silage production, or fish processing, among others.

Crude protein and crude fiber content of fish silage fermented with kombucha tea

Fish silage production using mineral acid is considered to have a negative effect because it is highly corrosive. As an alternative, kombucha tea which contains several organic acids and microorganisms can be used as a starter for fish silage fermentation. This study aims to determine the effect of different doses and duration of fermentation on the crude protein and crude fiber content of fish silage. The research method used was a factorial completely randomized design (CRD) method with 2 factors, namely factor A (dose) and factor B (fermentation time). The results showed that the difference in the dose of kombucha tea was not significantly different (p>0.05) on the increase in crude protein, while the difference in fermentation time was considerably different (p<0.05). Meanwhile, the difference in kombucha tea dose was not significantly different (p>0.05) on the decrease in crude fiber, but the difference in fermentation time was significantly different (p<0.05). Based on these results, there was an interaction between the dosage and the length of fermentation time on the crude protein content, while there was no interaction in crude fiber content. In conclusion, fermentation of fish silage using kombucha tea increased crude protein content while decreasing crude fiber content.

Diet impact on the reproductive characters of male red claw Cherax quadricarintus during the juvenile-adult transition

Male decapod reproduction involves gametogenesis, spermatozoa packaging in spermatophores, changes in cheliped´s growth, and specific behaviors such as courtship, male-male agoniztic interactions, and territory defense. These reproductive-related morpho-functional processes are supported by feed, one of the higher operative costs in aquaculture. This study aimed to evaluate the reproductive variables during the juvenile-mature transition of the male red claw Cherax quadricarinatus fed with two low-cost diets (T1 and T2). Pre-adult males (∼7 g) were individually distributed in plastic containers and fed a diet with fish silage (T1) (n = 9), a diet without fish silage (T2) (n = 8), and a commercial diet for ornamental fish used as a reference diet (T3) (n = 7). The proximal composition of T1, T2, and T3 was 34 %, 28 %, and 47 % for crude protein; 13 %, 9 %, and 6.5 for lipids; and 34 %, 47 %, and 28 % for carbohydrates, respectively. All males acquired sexual maturity with a body weight between 16 and 21 g. All groups showed similar chelae growth (based on the evaluation of the chelae height, and chelae thickness indexes) and red patch development. The gonadosomatic index was significantly lower in the T2 group with respect to T1. The lowest proportion of mature testicular lobes (filled with spermatids/spermatozoa) was detected in the T2 group (49 %), followed by T1 (59 %) group. There was also a lower protein content (∼ 27 %) in the vasa deferentia of the T2 group. However, all males showed a well-developed reproductive system and the histology of the testes and vasa deferentia showed no evidence of structural differences among groups. Under transmission electron microscopy analysis, both the primary and secondary layers of the spermatophore did not show qualitative differences among groups, including the spermatozoon morphology and acrosome size. This study highlights that males fed low-cost diets (0.56 and 0.65 U$S kg− 1, for T1 and T2 respectively), in particular T1, showed reproductive performances as good as the group fed on the reference diet. This is the first analysis of a pool of morpho-functional and biochemical reproductive variables in red claw males, to evaluate the effects of formulated diets on male sexual maturation.

Microbial count, chemical composition and fatty acid profile of biological silage obtained from pacu and spotted sorubim fish waste using lactic acid bacteria fermentation

With the increasing production and processing of fish, managing the generated waste is a growing concern. Fish processing by-products, like viscera, are rich in energy and nutrients and can be transformed into valuable raw materials, including fish silage, which represents an alternative to fishmeal. This study evaluated the quality of biological silage obtained from the fermentation of the waste of two fish species, pacu and spotted sorubim, by seven lactic acid bacteria inoculants. Cultivations were conducted using either 100% fish viscera or mixture of 90% fish viscera and 10% sugarcane molasses as the substrate at 30 or 35 °C, for 120 h, with an inoculum concentration of 6% (v/w) in the bioreactors. Results showed variations (P < 0.05) in microbiological count, chemical composition, and fatty acid profile in the silages after 5 days of fermentation. Spotted sorubim-based media supported better lactic acid bacteria growth, and the silages exhibited varying fatty acid profiles, depending on the formulation. Media inoculated with Lactobacillus brevis NRRL-B 4527 containing 90% spotted sorubim viscera and 10% sugarcane molasses at 30 °C had the highest protein content (44.6 ± 0.7% dry basys). Oleic (C18:1n-9), palmitic (C16:0), and stearic (C18:0) acids were the most abundant fatty acids. The LAB/MES ratio of 0.96 and pH final of 4.21 underline the microbial quality of this silage.

Assessing the Changes in Protein Content During the Ensilage of the Indian Mackerel (Rastrelliger kanagurta) by Biological Method

Fish silage is a liquefied product resulting from tissue hydrolysis and the richness of the silage is characterized by its nutritional profile comprising of proteins, amino acids, and fats. For the production of fish silage of high nutritional value, a precise assessment of the degree of hydrolysis, particularly proteolysis becomes a paramount importance. The goal of this study is to assess the changes in protein content in fish silage prepared from the Indian mackerel (Rastrelliger kanagurta) waste using 10% (v/w) sugarcane molasses, during 8 days of fermentation (DoF). The resultant ensiled product was evaluated for changes in titratable acidity, nutrients, total protein, total carbohydrate, total lipids content, and amino acid composition. Altogether, 17 types of amino acids were identified. Concentrations of total amino acids (TAAs, 15.627 ± 0.03 mg/g) and free amino acids (5.556 ± 0.08 mg/g) peaked at the end of 6 DoF with the predominance of histidine, arginine, alanine, asparagine, aspartic acid, and glutamic acid. Results of the non-metric multidimensional scaling (nMDS) plots and one-way analysis of similarities (ANOSIM) test indicated significant differences in the composition of TAAs at different DoF were discernible (nMDS, stress 0.03162, one-way ANOSIM R = 1; p < 0.0001). Similarity percentage (SIMPER) analysis indicated that the maximum content of amino acids (TAA and FAA) were released in silage during 4–6 DoF. A significant difference was observed in concentrations of most amino acids except cysteine, serine, and tryptophan (ANOVA, p < 0.05) at 2, 4, 6 and 8 DoF. Considering the vital role played by amino acids in providing resistance to plant pathogens as well as contributing to animal nutritional supplements, the results of the present study are highly noteworthy.

Pilot-scale valorisation of salmon peptone into polyhydroxyalkanoates by mixed microbial cultures under conditions of high ammonia concentration

The aquaculture industry produces vast amounts of organic side streams that are often ensilaged for later use in low value applications. However, the potential of converting fish silage, particularly the proteinaceous fraction, into more economically valuable products such as biodegradable polyhydroxyalkanoates (PHA), has not been explored. This study investigates the valorisation of salmon peptone, the proteinaceous fraction obtained from salmon silage, into PHA by mixed microbial cultures (MMC) under conditions without nutrient limitation, where the high concentration of ammonia (up to 2.3 ± 0.2 gN/L) which the culture was subjected to has not been previously reported. Acidogenic fermentation of salmon peptone (SP) was attained in a continuous reactor, resulting in the production of a fermentate rich in acetate and butyrate (16.4 ± 1.6 gCODFP/L). The enriched MMC with PHA-accumulating organisms was selected in a sequential batch reactor (SBR) under nutrient-rich conditions (100 gCOD: 27.6 gN: 0.48 gP at OLR 7.1 gCODFP/(L.d)). The dominant microorganisms in the enriched culture were from the genus Brachymonas, which are described as capable of simultaneous cell growth and PHA accumulation, storing up to 53.0 ± 3.4% wt. of P(3HB-co-3HV) with a 3HV content of 34% wt.. Despite the high ammonia concentration and constant nutrient availability, a good overall PHA yield (189 gPHA/kgSP) and global volumetric PHA productivity (3.10 ± 0.11 gPHA/(L.h)) were achieved. The results demonstrate the technological feasibility of producing PHA from salmon peptone under conditions that are typically considered unfavorable for PHA accumulation, which represents a significant novelty of this work.

Fish waste silage, a green process for low feedstock availability. A Review

Introduction. Different fishing activities generate a waste volume related to the processing species (viscera, heads and bones), the discards of the companion fauna, species of low commercial value and the losses related to handling problems. Fish meal production is the most common process for recovery nutrients from these fish processing byproducts. However, those places with reduced infrastructure or where the volume of wastes produced do not justified the economic equation for conversion into fish meal or oil, the biological silage could be the technology of choice to promote a sustainable waste management. Objective. To compilate, organize and summarize literature related to biological fermentation of fish waste and its applications. Development. A bibliographic review was carried out (January 1994 - December 2020) referring to the comprehensive use of fishing residues mainly focused on the use of lactic acid bacteria in fish waste fermentation. The information was organized in different sections: fish silage, lactic acid bacteria and carbohydrate sources for biological silage. Conclusions. The studies analyzed in this review highlight the possibility of using a wide variety of carbohydrate sources, biological starters and fish waste fermentation conditions. The satisfactory results show the potential use of fish waste in different applications. This work could contribute to the fisheries that decide to adopt this kind technology in order to provide an innovative and viable recycling bioeconomy.

Pengujian Mutu Silase Ikan Tembang yang Ditambahi Bakteri Asam Laktat (Konsentrasi 20%) Tepung Jagung Dengan Atau Tanpa Larutan Urea

Fish silage is a semi-liquid product of fish preservatives with the addition of lactic acid, to change the fermentation process that converts carbohydrate sources into acids. Silage can be processed using lactic acid bacteria (LAB). The lactic acid bacteria used in this study were sourced from palm sap isolates. Lactic acid bacteria are a type of beneficial non-pathogenic bacteria that are very helpful in the fermentation process of feed and food ingredients. To determine the effect of adding 10% LAB concentration combined with corn flour and urea on the quality of fish silage and to compare the quality of fish silage based on various aspects of sensory evaluation, namely (aroma, texture, color) and the degree of fish silage. The stages of implementing this research include sampling, making fish silage, fermentation and organoleptic testing and testing the degree of storage. Based on the results of the study, it was found that the results of the organoleptic tests carried out showed that the fish silage produced was of good quality which was characterized by an acidic silage aroma, a silage texture that was not lumpy and not too soft, and an increase in the color of brown silage. The results of the study that the addition of 10% LAB combined with ground maize and urea gave a significantly different effect (P&lt;0.05) on the quality of fish silage. Combined use of fish silage will affect the pH of the silage.

Use of fish waste to silage preparation and its application in animal nutrition

In recent years, global aquaculture production has increased, leading to an increase in fish waste. These wastes, which in many cases are disposed directly without trying to take advantage of them, are a major environmental and economic problem that may affect the sustainability of the fishing and aquaculture industry. Therefore, their use seems necessary to reduce pollution and make the aquatic industry more efficient. Most of well-known technologies for using fish waste are not economically attractive due to the need for high initial investment. But an easy and inexpensive way to use these wastes is to convert them into silage. Fish silage is a product of good nutritional quality included in animal diets as part of the feed. Fish silage is a liquid product made from whole fish or parts of it to which lactic acid-producing acids, enzymes or bacteria are added, and the liquefaction of the material indicates the action of enzymes present in the fish. Therefore, the purpose of this review is to investigate the use of aquatic waste for preparing silage and the possibility of using it in animal nutrition.

The role of microorganisms in solid biofertilizer production

Trials of making organic fertilizer using seaweed, fish silage, molasses, and a consortium of microbes were carried out. This study aimed to determine the activity of Bacillus subtilis, Pseudomonas florescent, and Trichoderma sp to produce micro and macro nutrients, humic acid, water content, and growth hormone. The organic fertilizer formula consisted of 26.6% sargassum flour, 16% fish silage, 1.8% molasses, 2.4% K. alvarezii paste; and 53.2% sargassum paste. The treatments consisted of formulated without adding microbial consortium (SK) and with adding microbial consortium (SM) as much as 10% volume per weight (v/w), then fermented for 10 days at room temperature. The balance values of growth hormone auxin (IAA), gibberellin (GA3) and cytokinins in SM treatment were the best measured at 181 ppm, 73 ppm, and 120 ppm, respectively.

Potential inert diets to supplement Artemia in larviculture of the giant Africa river prawn Macrobrachium vollenhovenii (Herklots, 1857) (Crustacea: Palaemonidae)

The protocol of culture of Macrobrachium vollenhovenii the main indigenous candidate for freshwater prawn culture in Africa is still under study. Though just few information exists, the transition of larvae from stage V to stage VI has been reported as the critical rearing period in larviculture. This study was to evaluate the efficiency of two locally diets to supplement Artemia in the feeding scheme from stage V to post larvae in the larviculture of this species. The two experimental diets were differentiated by the main source of protein: fish silage (Diet 1) and shrimp meat (Diet 2). One batch of larvae was cultured till stage V. The experiment itself was conducted in triplicate with three treatments: feeding Artemia exclusively (TA, control); fed partial replacement of Artemia with inert diet 1 (T1) or fed partial replacement of Artemia with diet 2 (T2). Larval development in T2 was significantly faster than TA and T1. Survival rate was significantly higher in T2 (12.64±1.2%) than TA (6.57±0.29%) and T1 (6.77±0.17%). The total length of larvae in T2 was significantly higher than TA and T1. Though the highest survival obtained in this study is still low, it’s however higher than those reported in other studies with this species. Also, the importance of finding alternatives to Artemia and cheaper diets remains very important.

Supply of Fish Waste and Level of Awareness of Fish Vendors in the City of Baybay, Leyte Province on the Potential Use of Fish By Products as Local Fish Silage

Fish by-products from fish markets represent a huge portion of underutilized resources that could be a potential as a source of protein-rich feed ingredient. This study was conducted to determine the supply of fish waste and awareness of fish vendors on the potential use of fish by-products as silage. This study specifically determined the socio-demographic profile of fish vendors in the barangays and public market of Baybay City. Additionally, it identified the supply and means of disposal of local fish by-products and most importantly, determined the awareness of fish vendors on the utilization of fish by-products. Using descriptive research design, a total of 42 respondents were surveyed and interviewed. The data were analyzed using descriptive statistics such as percentage and ranking. The results showed that fish vendors were mostly female with age ranges from 51- 60 years and high school graduates. These vendors earned around P10, 000.00 per month from selling fish that were sourced out from nearby towns. Top fish varieties being sold in Baybay City public market were Blackfin scad, mackerel tuna, and milkfish were among the top fish being sold in Baybay City. Fish waste by products weighing1-5 kilograms per vendor were disposed based on three (3) times a day based in the daily schedules using garbage truck to prevent foul odors. These fish wastes were not sold to consumers, although a few would ask for it as pet food. With this, there is a huge potential on the utilization of these by products as animal feeds, and therefore offers a possible sustainable project between the government and the academe.

Potential role of sulfide precipitates in direct interspecies electron transfer facilitation during anaerobic digestion of fish silage

Fish waste (FW) contains large amounts of protein and is a challenging feedstock for biogas production due to possible H₂S and ammonia generation. Adding FeCl3 to an anaerobic digester can precipitate H₂S. Mackinawite and greigite are conductive and magnetic substances formed from H₂S precipitation. Direct interspecies electron transfer (DIET) can be stimulated by developing these conductive materials and by applying an external magnetic force. In this study, FW was digested in batch reactors and exposed to magnets magnetic fields from 3 to 115 mT. The results showed that the use of magnetic fields could increase the biomethane yield by up to 36 %. XRD analyses showed that mackinawite and greigite were accumulating in the solid phase in digesters added FeCl3. Genetic analysis of the microbial community suggested that applying a magnetic field not only increased the relative abundance of protein-hydrolyzing bacteria but also potentially improved methane production through DIET.

Balık silajı üretimi için basit bir yöntem: İnokulum olarak yoğurt kullanımı

The evaluation of seafood processing wastes is an important issue in terms of both preventing environmental pollution and adding value to these wastes economically. The most practical method that can convert seafood processing waste into a valuable feed source and plant fertilizer is to make silage. In this study, the ripening times and nutritional components of fish silages prepared with direct addition of lactic acid bacteria culture (Streptococcus thermophilus), acidifying chemicals (formic acid) and yogurt, which is a fermented food, were compared. In the research, sardine fish (Sardina pilchardus) wastes (head, skin, bones, internal organs, etc.) were used in fish silage production. It was observed that all fish silages completed the ripening phase within a maximum of 10 days. It was determined that the moisture, ash, protein and lipid contents of the groups prepared with acid, bacteria and yoghurt ranged between 63-66%, 5.6-5.7%, 11.3-11.8% and 12.18-13.65%, respectively. As a result of the research, it was observed that fish silages made with the addition of yoghurt as an alternative to silages made with direct addition of pure bacterial culture or acid addition met the expectations in terms of both ripening time and nutrient components.

Quality of Chemically Processed Flying Fish (Hyrundicthys oxycephalus) Waste Silage

Flying fish are the fish that are widely found in the waters of the Makassar Strait, especially in Majene Regency. During the harvest season, flying fish leave a lot of waste that pollutes the environment. This research aimed to evaluate flying fish waste silage's physical and chemical qualities. The design used was a completely randomized design (CRD) with four treatments and four replications groups. To process the sample, formic acid at concentrations of 0%, 2.5%, 3%, and 3.5% was used. Anova was applied for data analysis, followed by Duncan's test if the treatments differed significantly. Parameters observed were chemical quality, including crude protein and fat content, total bacteria count, and pH, while physical-chemical quality included aroma, color, and texture of flying fish waste silage. The results showed that the addition of formic acid to fly fish silage had a significant effect (P &lt; 0.05) on protein, fat, pH, and total bacteria levels but had no significant effect (P&gt; 0.05) on the aroma, color, and texture of the hay. This research concludes that chemically processing flying fish silage with the addition of 2.5% formic acid can increase the protein content to the optimum level in the P1 treatment resulting in the highest protein content of 48.81% and the fat content of 1.63%, pH 3.5, total bacteria 4 x 104, sour taste, gray color and liquid texture that can be safely used as raw feed.

Confirming the presence of selected antibiotics and steroids in Norwegian biogas digestate

Farms utilizing sewage sludge and manure in their agronomic plant production are recognized as potential hotspots for environmental release of antibiotics and the resulting promotion of antibiotic resistance. As part of the circular economy, the use of biogas digestates for soil fertilizing is steadily increasing, but their potential contribution to the spreading of pharmaceutical residues is largely unknown. Digestates can be produced from a variety of biowaste resources, including sewage sludge, manure, food waste, and fish ensilage. We developed a method for the detection of 17 antibiotics and 2 steroid hormones and applied the method to detect pharmaceutical residues in digestates from most municipal biogas plants in Norway, covering a variety of feedstocks. The detection frequency and measured levels were overall low for most compounds, except a few incidents which cause concern. Specifically, relatively high levels of amoxicillin, penicillin G, ciprofloxacin, and prednisolone were detected in different digestates. Further, ipronidazole was detected in four digestates, although no commercial pharmaceutical products containing ipronidazole are currently registered in Norway. A simplified risk assessment showed a high risk for soil microorganisms and indicates the tendency for antibiotic-resistant bacteria for penicillin G and amoxicillin. For prednisolone and ipronidazole; however, no toxicity data is available for reliable risk assessments.Graphical abstract