Replacement Of Fish Meal Research Articles

Effect of replacing dietary fish meal protein with combined animal meals on the growth performance of olive flounder (Paralichthys olivaceus)

The effect of various levels of fish meal (FM) protein substitution with combined animal meals on the growth and feed utilization of olive flounder (P. olivaceus) was elucidated. A total of 630 juvenile olive flounder averaging 12.5 g was distributed to 21 tanks, with 3 tanks per diet. A two-way ANOVA experimental design was adopted, incorporating two replacement sources [combined plasma powder and chicken by-product meal (PC), and combined plasma powder and tuna by-product meal (PT)] and three FM replacement ratios (25%, 50%, and 70%). A control (Con) diet contained 70% FM. In the Con diet, 25%, 50%, and 70% FM protein were substituted with PC and PT, labeled as the PC25, PC50, PC70, PT25, PT50, and PT70 diets, respectively. Fish were hand-fed to apparent satiation twice a day for 56 days. Upon completion of the feeding experiment, both dietary replacement source and ratio significantly affected the weight gain (WG), specific growth rate (SGR), and feed consumption of fish (P < 0.001 for all). The PT replacement source achieved better WG, SGR, and feed consumption than the PC replacement source. Additionally, dietary increased FM replacement ratio reduced WG, SGR, and feed consumption. WG, SGR, and feed consumption of fish fed the PC25 and PT25 diets were comparable to fish fed the Con diet, but superior to fish fed all other diets, except for feed consumption of fish fed the PT50 diet. None of proximate composition, AA profiles, plasma parameters as well as selected innate immunity (lysozyme and SOD activities) of fish was influenced by dietary treatments. In conclusion, up to 25% of FM protein (35.7% of FM replacement) in a 70% FM-based diet could be successfully substituted with PC and PT without negatively affecting growth, feed consumption and utilization, proximate composition, AA profiles, and selected innate immunity (lysozyme and SOD activities) of olive flounder.

The Effects of Replacing Fish Meal Protein with Black Soldier Fly Meal and Sodium Butyrate Supplementation on the Growth Performance, Lipid Peroxidation, and Intestinal Villi Status of Jade Perch, Scortum barcoo Fingerlings

This study investigated the effects of different protein sources and butyric acid contents in aquafeed on the growth, survival rate, lipid peroxidation enzymes, and intestinal villi of 7.3 g jade perch, Scortum barcoo. The experimental treatment groups were the whole fish meal protein (FM) group, the FM + butyric acid (FMB) group, the 50% fish meal protein and 50% black soldier fly meal protein (FBM) group, the FBM + butyric acid (FBMB) group, the whole black soldier fly meal protein (BM) group, and the BM + butyric acid (BMB) group. The experimental results showed that the jade perch fed with the FMB feed had a significantly higher weight gain rate and antioxidant enzyme activity than the other treatment groups. The red blood cell count, hemoglobin concentration, and hematocrit contents in the blood of jade perch were not affected by the protein source, but they increased with the addition of butyric acid. The intestinal villi length of the jade perch that were fed diets containing butyric acid were significantly higher than that of the jade perch that were fed diets without butyric acid supplementation. The results of this study show that the addition of butyric acid to a balanced feed composed of protein can contribute to the growth of jade perch.

The Effects of Replacing Fish Meal with Enzymatic Soybean Meal on the Growth Performance, Whole-Body Composition, and Health of Juvenile Gibel Carp (Carassius auratus gibelio)

Fish meal (FM) constitutes the main, expensive component in aquatic diets. However, the supply of FM is no longer sufficient to sustain global aquaculture production. This study had the primary goal of assessing if the replacement of FM with enzymatic soybean meal (ESBM) can affect the performance of growth and immunological response in juvenile Gibel carp. Juvenile fish with an initial weight of 45.02 ± 0.03 g were arbitrarily assigned to 18 fish cages of 1 m3 each, then fed with diets of different levels of ESBM (0% (control group), 4%, 8%, 12%, 16%, and 20%) for 159 days. These diets corresponded, respectively, to the replacement levels of 0% (control group), 20%, 40%, 60%, 80%, and 100% FM by ESBM. For the parameters of growth and whole-body composition, no obvious differences were found between the control group and other replacement levels (p &gt; 0.05). Similarly, none of the replacement levels showed significant effects for alanine transaminase (ALT), total cholesterol (TC), alkaline phosphatase (ALP), and glucose (GLU) levels (p &gt; 0.05). Malondialdehyde (MDA) levels, as well as the activities of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in plasma, were not significantly affected at all replacement levels, according to the findings of this study (p &gt; 0.05). The replacement level of 60% significantly increased the activities of catalase (CAT), whereas the replacement levels of 20% and 100% markedly decreased the activities of this enzyme (p ˂ 0.05). Hepatic and intestinal tissues in this study did not show obvious alterations at all levels of replacement.

Protein Fishmeal Replacement in Aquaculture: A Systematic Review and Implications on Growth and Adoption Viability

Aquaculture is growing rapidly as a food-producing sector and in recent years fishmeal prices have climbed more than two-fold on a global scale. This review of previous studies was performed to contribute to the extant literature on the aquaculture sector to aid cost reduction of aquafeeds by identifying substitute proteins that can replace fishmeal. The review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) using the SCOPUS and WOS (Web of Science), DOAJ (Directory of Open Access Journals), Academia, and PubMed Central databases. A total of 59 articles were included in the synthesis after screening for duplicates and articles that did not conform to the criteria. Results have shown that the 100% replacement of fishmeal with blood meal (BM) did not affect the growth of fish, nor did the 75% to 100% combination of poultry-by-product (PBM), feather meal (FEM), and BM. Moreover, a 10% replacement of fishmeal using seaweed (Gracilaria arcuata) had no adverse effect on the feed efficiency and growth performance of tilapia. Similarly, a 50% replacement of fishmeal using black soldier fly (Hermetia illucens), and a 25% replacement using soybean (Glycine max) also showed better results for fish growth. Our review shows that alternative protein can replace fishmeal in the aquaculture sector and reduce the cost of aquafeeds since alternative proteins are much cheaper than the usual fishmeal. Adoption of these alternative protein sources hinges on financial support, start-up incentives for companies, and ongoing studies on waste-to-feed production, which the government can also support.

In vitro modelling of the influence of alternative feeds (Hermetia illucens, Arthrospira platensis) on the resistance of different rainbow trout populations (Oncorhynchus mykiss) against the viral haemorrhagic septicaemia virus and Yersinia ruckeri.

Replacing fishmeal, a finite resource with high market demand, in the diet of carnivorous rainbow trout with proteins from alternative sources may be a challenge for these fish. Therefore, this study investigated whether replacing fishmeal with protein derived from Hermetia illucens or Arthrospira platensis could promote disease susceptibility in local trout populations with different growth performance. This was assessed in vitro by measuring susceptibility to infection with the viral haemorrhagic septicaemia virus (VHSV) or the bacterium Yersinia ruckeri. Analysis of fin tissue explants and primary cell cultures from scales from the three trout populations infected in vitro with VHSV and gill explants infected with Y. ruckeri showed no significant differences in virus replication or bacterial counts. Evaluation of the virucidal or bactericidal effect of skin mucus showed a significant reduction in viral load and bacterial count for all samples with mucus addition, but no significant difference was observed between the experimental groups. This study documents no apparent impairment of innate immune mechanisms in the skin and gills of trout after feeding a diet replacing fishmeal with Arthrospira or Hermetia proteins. This underlines the potential of these alternative protein sources for the further development of sustainable trout aquaculture.

Influence of genetic adaption of rainbow trout (Oncorhynchus mykiss) fed with alternative protein sources based on Arthrospira platensis and Hermetia illucens on intestinal health and animal welfare

Genetic adaptation to new environmental conditions, such as changing diets, has always played a key role in the evolution of animals. Fish, in particular, have a great genetic potential for adaptability to regional environmental demands. Feeding diets devoid of marine resources to carnivorous fish species is paramount to enable fully sustainable aquaculture and independence of capture fisheries. Therefore, novel sources of protein substituting fishmeal in fish feed are of increasing interest in aquaculture. However, the use of plant-based protein sources in the diet of carnivorous fish is in controversial discussion because of their association with several issues related to food conversion, growth rate, fish health and welfare effects. The current study aims at making use of the genetic variability of rainbow trout (Oncorhynchus mykiss) in order to gain new insights into their adaptability to innovative raw materials with a particular focus on the question of how the replacement of fishmeal by Arthospira platensis and Hermetia illucens in fish feed affects the intestinal health. Therefore, 20% fishmeal of the total composition was completely replaced in each case with Arthrospira platensis or Hermetia illucens. The results showed that the stress response, investigated by analysing the concentration of heat shock protein 70 in liver samples, proved to be at very low values for all investigated groups. A chronic stress exposure due to the supplementation could thus be excluded. Regarding growth, the genetic background played a decisive role. Despite morphological and histological changes in the anterior intestine of experimental feeding groups, no negative influence on growth could be detected. A significantly higher expression of occludin in the posterior intestine of the Arthrospira groups with respect to the epithelial barrier was noted. Altogether, no signs of cell infiltration were detected in the intestines of the animals despite the Arthrospira fed groups and one Hermetia fed group showing partially significantly higher gene expressions according to IL1β, TNFα and singular antimicrobial peptides than fish from other feedings. Therefore, the current study reveals that supplementing the fishmeal portion of rainbow trout diets with Arthrospira platensis or Hermetia illucens does not negatively affect fish health and animal welfare.

Effect of different inclusion levels of defatted Hermetia illucens larvae meal on fillet quality of gilthead sea bream (Sparus aurata)

Abstract In recent years, insect meal has attracted increasing interest as an innovative protein source to replace fish meal in feed formulation due to its valuable nutritional profile. This research aimed to compare the effects of different dietary inclusion levels (5, 10, and 15%) of Hermetia illucens (HI) larvae meal on Sparus aurata (initial weight: 98.6 ± 0.6 g) sensorial, technological, and nutritional fillets quality. Fish were fed experimental diets over 113 days. Results showed that the inclusion of defatted HI larvae meal did not induce off-flavours in gilthead sea bream fillets. No significant differences were found in appearance, mouthfeels, and texture, while a difference emerged in the trait ‘cooked chicken breast’ for odour and flavour characteristics. Moreover, fillets’ quality traits and proximate composition analyses performed did not show significant differences between the treatments. The fillets’ fatty acid content showed that higher inclusion of HI meal leads to higher saturated fatty acids content, while no significant difference in polyunsaturated fatty acids was observed among treatments. Results have a positive implication as dietary HI did not negatively affect the fatty acids composition or quality of sea bream fillets.

Partial replacement of fish meal by cottonseed protein concentrate and the effects of preconditioning water content and die temperature on pellet physical quality of extruded floating fish feed

A two-factorial central composite design was performed to investigate the effects of preconditioning water content (PCwater: 21, 22.5, 26, 29.5 or 31%) and die temperature (Dtemp: 115, 119.4, 130, 140.6 or 145 ℃) on the physical properties of extruded floating fish feed. This design was applied to two separate diet formulas to study the effect of cottonseed protein concentrate (CPC) inclusion (replacing 67% of fish meal-FM in the diet). A total of 26 batches of diets were prepared. Response surface methodology was used for regression and parameter optimization. Averaged over all PCwater and Dtemp combinations, CPC-pellets had a lower bulk density, oil leakage, higher expansion rate, oil absorption, hardness, pellet durability index and a longer hydration time than FM-pellets. A negative correlation between oil absorption and oil leakage was presented in the CPC-pellets but not in the FM-pellets. Moreover, the influence of PCwater on the PPQ was uniform across both formulas except for oil leakage. However, the effect of Dtemp on the PPQ differed between the formulas. For oil leakage, it was maximal at both the highest PCwater and Dtemp combination in the FM-pellets, while it was maximized at both the lowest PCwater and Dtemp combination in the CPC-pellets. Furthermore, exchanging fish meal with CPC improved the optimal processing conditions and enlarged the operating window to produce the desired feed. This reduces water and energy consumption in feed production.

Breeding Substrate Containing Distillation Residues of Mediterranean Medicinal Aromatic Plants Modulates the Effects of Tenebrio molitor as Fishmeal Substitute on Blood Signal Transduction and WBC Activation of Gilthead Seabream (Sparus aurata).

This work assesses the dietary use of two insect meals of Tenebrio molitor (TM) larvae reared in conventional (TM-10) or MAP-enriched substrates (MAP-TM-10) as fish meal replacements (10%) in the diets of gilthead seabream (Sparus aurata). Fish (n = 4500; 207.19 ± 1.47 g) were divided into three groups with triplicates: control (fed conventional diet), TM-10, and MAP-TM-10 groups. The fish were reared in floating cages for 12 weeks and the dietary effects on white blood cell activation, heat shock proteins, MAPKs, and apoptosis of the fish were evaluated. The MAP-TM-10 group exhibited the highest eosinophilic induction. Phosphorylated levels of p38 MAPK, p44/42 MAPK, HSP70, and HSP90 increased in the TM-10 and MAP-TM-10 groups. In terms of apoptosis, Bax levels were lower in the TM groups compared to the control, and the MAP-TM-10 group showed even lower levels than the TM-10 group. Bcl-2 levels increased in the TM-10 group compared to the control, and further increased in the MAP-TM-10 group. The Bax/Bcl-2 ratio, an apoptosis indicator, decreased in the TM groups, with the MAP-TM-10 group showing a further decrease compared to TM-10. These findings suggest that insects' breeding substrate being enriched with MAPs modulated the effect of TM on cellular stress and apoptosis.

Dried porcine soluble benefits to increase fish meal replacement with soy protein concentrate in large yellow croaker Larimichthys crocea diet

AbstractThe effect of dried porcine soluble (DPS) supplementation on replacement of dietary fish meal with soy protein concentrate (SPC) for large yellow croaker, Larimichthys crocea, was assessed in a feeding trial conducted in inshore net pens. Five isoproteic and isolipidic diets were tested. A basal diet (BD) contained 400 g/kg fish meal, and SPC was used as an alternative ingredient to replace 40% (F24) and 60% (F16) of the fish meal in BD at an equal protein basis. DPS was added at 5 g/kg in F24 (FD24) and F16 (FD16). Fish weighing 33.6 ± 7.4 g were fed with the test diets in 1.5 × 1.5 × 2 m net pens for 9 weeks. The fish meal replacement level significantly affected weight gain, feed conversion ratio, phosphorus retention efficiency, body phosphorus content, and ratio of fish meal consumption to fish production (RCP), while the DPS supplementation level significantly affected weight gain. The weight gain of fish fed FD24 was higher than that of fish fed F16, while no significant difference was found in weight gain between fish fed BD and fish fed FD24, F24, FD16 and F16. The feed cost, RCP and phosphorus waste of fish fed BD were higher than those of fish fed FD24, F24, FD16 and F16. Fish fed FD24 exhibited the best production performance, and the production performance of fish fed F24 and FD16 was close to that of fish fed BD. The present study indicates that the fish meal level in large yellow croaker diet could be lowered to 240 g/kg with SPC alone as a fish meal substitute, and could be further reduced to 160 g/kg by supplementation of 5 g/kg DPS. Therefore, DPS supplementation can benefit to increase fish meal replacement with SPC in large yellow croaker diet.

Farmed Fish Feeds: Use of Non-Conventional Feed as Fishmeal Replacement in Nigeria

Fish feeds are an integral part of commercial and personal aquaculture, which provides a balanced diet and nutrition for farmed fish. High cost and competition with human food of fish feed is a major concern amongst the livestock and aquaculture feed industries. The objective of this paper is to analyze the current state of understanding on the use of non-conventional feed to replace normal fish feeds in Nigeria using information from secondary data. The mastery and use of substitute sources of fishmeal at all stages of fish development is crucial to reducing the demand on aquatic resources caused by the use of fishmeal in fish feed. Non-conventional feed ingredients are not usually the traditional ingredients used for commercial fish feed production. Many unconventional sources are of very good nutrient profiles which when incorporated into feeds can meet parts of the protein and energy requirements of the fish. Most of these indigenous fish feed resources are non-competitive in terms of human consumption, their prices are relatively very low and sometimes are of no cost value. They are usually byproducts or waste products from agricultural industries, domestic waste, and wild plants, thus their utilization as feed resources can help to reduce the cost of fish feeds and fish production in Nigeria.

Dietary starch level affects nutrient digestibility, faecal waste production and characteristics in yellowtail kingfish (Seriola lalandi) depending on the level of fish meal replacement

Yellowtail kingfish have a poor faecal integrity when fed with pelleted diets which may be due to the presence of dietary starch. Moreover, whether dietary starch interacts with plant protein ingredients, is not known. In this study, we investigated the effect of dietary starch level, protein source and their interaction effect on faecal waste production and characteristics (visual appearance, faecal removal efficiency and particle size distribution (PSD)). Four diets were formulated according to a 2 × 2 factorial design (starch level × protein source). The effect of starch level was tested by either including 0% (LS - low starch, 4% starch) or 20% gelatinized wheat flour (HS - high starch, 20% starch). FM diets contained fish meal as protein source, whilst at FM/P diets approximately 65% of the fish meal was replaced by plant protein ingredients. Twelve tanks were stocked with 21 fish (mean initial weight 53 g) and fish performance, nutrient digestibility, faecal waste production and characteristics were evaluated over a 36-day experimental period. Both starch level and protein source affected the organic matter digestibility (p < 0.05). The effects of starch and protein source were additive regarding macro nutrient digestibility indicated by the absence of an interaction effect (p > 0.05). Growth was similar between the FM and FM/P at low starch diets (p < 0.05), but was reduced at the FM/P at high starch inclusion level (p < 0.05). The high starch and FM/P diets resulted in more faecal waste production (p < 0.05). Faecal integrity of yellowtail kingfish was adversely affected by starch inclusion. Fish receiving low starch diets excreted faecal pellets and short strings, while faecal waste collected from fish receiving high starch diets was classified as inconsistent. This was also reflected in a higher faecal removal efficiency and larger faecal PSD for fish receiving the low starch diets compared to the high starch diets (p < 0.05). No protein source or interaction effect was observed for faecal removal efficiency (p > 0.05). Consequently, lowering starch level and excluding plant protein ingredients reduced the amount of non-removed faeces by 71.1% and 30.6%, respectively. In summary, our study showed that the reduction of dietary starch offers possibilities to replace fish meal with plant protein ingredients without limiting growth performance in yellowtail kingfish. Moreover, lowering dietary starch level may have the potential to reduce solid loading in recirculating aquaculture systems for yellowtail kingfish.

Optimization of fish and plant production in tilapia-spinach aquaponics systems using black soldier fly larvae meal and mineral supplementation

Aquaponics is a sustainable food production system that combines aquaculture and hydroponics. Fishmeal is a common protein source in aquaponics feeds, but it is expensive and has environmental and ethical issues. Black soldier fly larvae (BSFL) are a promising alternative protein source that can be produced from organic waste. However, the optimal level of fishmeal replacement by BSFL meal and the effects of mineral supplementation on fish and plant growth, nutrient utilization, and microbial quality in aquaponics systems are not well understood. In this study, the researcher conducted three experiments to evaluate the effects of full-fat (FF) BSFL meal, defatted (DF) BSFL meal and mineral supplementation on tilapia-spinach aquaponics systems. The researcher found that FF or DF BSFL meal can replace up to 30% of fishmeal protein in tilapia-spinach aquaponics systems without compromising fish and plant growth, nutrient utilization, or microbial quality. Mineral supplementation can further enhance the performance of tilapia fed with FF or DF BSFL meal in aquaponics systems. This study provides valuable information for optimizing fish and plant production in tilapia-spinach aquaponics systems using BSFL meal and mineral supplementation as sustainable protein and mineral sources.

Replacement Effect of Fish Meal by Plant Protein Sources in Olive Flounder (Paralichthys olivaceus) Feeds with an Addition of Jack Mackerel Meal on Growth, Feed Availability, and Biochemical Composition.

Application of feed stimulants is very helpful to increase the feed intake of fish, especially in the development of low fish meal (FM) diets. FM replacement effect by various plant protein sources (corn gluten meal (CGM), soy protein concentrate (SPC), and corn protein concentrate (CPC)) in diets with an addition of jack mackerel meal (JMM) as feed stimulants on growth, feed availability, and biochemical composition of olive flounder was elucidated. An experimental design of two-way (two replacement levels (25% and 50%) × 3 replacement sources (CGM, SPC, and CPC)) analysis of variance was adopted. Seven diets were formulated. Amount of 60% FM was contained in the control (Con) diet. In the Con diet, 25% and 50% FM were replaced by CGM, SPC, and CPC with an addition of 12% JMM as feed stimulants, referred to as the CGM25, CGM50, SPC25, SPC50, CPC25, and CPC50 diets, respectively. Four hundred and twenty juvenile fish were distributed into 21 flow-through tanks. All diets were assigned to triplicate groups of fish. Fish were hand-fed to satiation twice a day for 56 days. Both dietary replacement levels and sources had statistical effect on weight gain (P < 0.0001 and P < 0.045, respectively), specific growth rate (SGR) (P < 0.0001 and P < 0.033), and feed consumption (P < 0.0001 and P < 0.03) of fish. Dietary increased FM replacement levels lowered weight gain, SGR, and feed consumption of fish. Weight gain, SGR, and feed consumption of fish fed the Con and CGM25 diets were statistically (P < 0.05) greater than those of fish fed the CGM50, SPC50, and CPC50 diets. Both replacement level and source had no statistical effect on feed utilization, biochemical composition except for statistical effect of replacement source on glycine content of fish, and lysozyme and superoxide dismutase (SOD) activities of fish. FM up to 25% could be substituted with CGM, SPC, and CPC in the olive flounder feeds supplemented with 12% JMM as feed stimulants without compromising growth, feed utilization, and lysozyme and SOD activities.

Effects of Dietary Fish Meal Replacement with Alternative Protein Ingredients and Their Combinations on Growth Performance, Feed Utilization, Fillet Composition, and Biochemical Parameters of Red Seabream (Pagrus major).

The experiment was conducted to evaluate alternative protein ingredients in a low-fish meal (FM) diet for red seabream (Pagrus major). Twelve experimental diets were formulated. Control diet (CON) was designed to contain 60% FM. Other experimental diets were formulated by replacing 50% of FM from the CON with soy protein concentrate (SPC), corn gluten (CG), meat meal (MM), and/or chicken byproduct meal (CBM). Four diets were designed including one of SPC, CG, MM, or CBM as FM replacer and designated as SPC, CG, MM, and CBM. Six other diets were formulated by adding two ingredients as SPC and CG, SPC and MM, SPC and CBM, CG and MM, CG and CBM, or MM and CBM, and designated as SCG, SMM, SCM, CMM, CCM, and MCM, respectively. The 12th diet (MIX) was formulated by including SPC, CGM, MM, and CBM. Triplicate fish groups (50.2 ± 0.1 g) were hand-fed for 12 weeks. Weight gain (WG) of fish was significantly improved by MM and MCM diets compared to CG, SCG, CMM, and CCM diets. WG of CON, SPC, CM, SMM, SCM, and MIX groups were comparable with MM and MCM groups. The lowest WG was observed in CG and CMM groups. Feed efficiency (FE) was significantly higher in MM group compared to SPC, CG, SGC, and CMC groups. FE of MCM group was significantly higher than CG and SCG groups. Fillet linolenic acid (C18:2n-6) level in CG group was significantly higher than CON, MM, CM, SCM, CCM, and MCM groups. Serum lysozyme activity was significantly higher in MCM and MIX groups. Therefore, a high level of dietary CG reduces the growth performance and feed utilization of red seabream. A mixture of MM and CBM seems to be more efficient in replacing FM from red seabream diet.

Isolation and identification of protease-producing Bacillus amyloliquefaciens LX-6 and its application in the solid fermentation of soybean meal.

Soybean meal (SM) is considered an ideal substitute for fish meal; however, its application is mainly limited because of its antigen proteins, glycinin and β-conglycinin. To improve the value of SM in the aquaculture industry, we employed an aerobic bacterial strain (LX-6) with protease activity of 1,390.6 ± 12.5 U/mL. This strain was isolated from soil samples and identified as Bacillus amyloliquefaciens based on morphological and physiological biochemical characteristics and 16S rDNA gene sequence analyses. Subsequently, we quantified the extent of glycinin and β-conglycinin degradation and the total protein and water-soluble protein content after SM fermentation with B. amyloliquefaciens LX-6. At 24h of fermentation, the macromolecular antigen proteins of SM were almost completely degraded; the maximum degradation rates of glycinin and β-conglycinin reached 77.9% and 57.1%, respectively. Accordingly, not only did the concentration of water-soluble proteins increase from 5.74% to 44.45% after 48h of fermentation but so did the concentrations of total protein and amino acids compared to those of unfermented SM. Field emission scanning electron microscopy revealed that the LX-6 strain gradually disrupted the surface structure of SM during the fermentation process. In addition, B. amyloliquefaciens LX-6 exhibited broad-spectrum antagonistic activity and a wide pH tolerance, suggesting its application in SM fermentation for fish meal replacement.

Replacement of dietary fish meal by fermented soybean meal improves growth, energy metabolism, and innate immune response in Penaeus vannamei Boone, 1931 (Decapoda: Dendrobranchiata: Penaeidae)

Abstract Fishmeal (FM) is considered a preferred source of protein for aquatic feed due to its good palatability and digestibility, a balanced amino acid profile, and a low level of anti-nutritional factors (ANFs). Shortage of FM supply and increases in price, however, are major challenges faced by feed producers and aquaculture farmers. Fermented soybean meal (FSBM) has been proposed to partially replace FM because of its high nutritional value and low cost. The optimal FSBM concentration for substituting FM and effects of FSBM substitution on growth performance, energy metabolism, and immune response nevertheless remain unclear. We evaluated the effects of shrimp diets containing FSBM at 0% (FM), 25% (FSBM25), 50% (FSBM50), 75% (FSBM75), and 100% (FSBM100) on the shrimp Penaeus vannameiBoone, 1931. FSBM50 led to a significantly higher weight gain (postlarvae 1927.36 ± 46.64%, young juveniles 237.00 ± 8.25%, and juveniles 153.96 ± 2.18%) than the other experimental and control diets in different stages of the shrimp. The FM group consumed less oxygen than the experimental diet groups. FSBM75 and FSBM100 led to a significantly higher ammonia-N excretion than FM, FSBM25, and FBSM50. All experimental diet groups exhibited a significantly higher O:N ratio (8.3 ± 0.8–9.4 ± 1.7) than the FM group (7.1 ± 0.2). Shrimp fed with FSBM25- and FSBM50-containing diets exhibited an increased total hemocyte count, and FSBM25, FBSM50, and FSBM100 led to a significantly higher superoxide anion production than FSBM75 and FM. FSBM substitution in shrimp diets resulted in a significantly higher phagocytic activity than the FM diet, suggesting that FSBM substitution improves the cell-mediated immune response in shrimps. In challenge trials with white spot syndrome virus (WSSV), all experimental diets led to a higher survival rate than the FM diet, and in Vibrio parahaemolyticus challenge trials, FSBM50 led to a higher survival rate than the other experimental and control diets, indicating that FSBM substitution in shrimp diets could improve the defense capacity of shrimps against WSSV and V. parahaemolyticus.

Using Azadirachta indica protein hydrolysate as a plant protein in Nile tilapia (Oreochromis niloticus) diet: Effects on the growth, economic efficiency, antioxidant-immune responseand resistance to Streptococcus agalactiae.

A feeding trial for 90 days was conducted on Nile tilapia (Oreochromis niloticus) (average weight: 25.50 ± 0.05 g) to evaluate the effect of dietary inclusion of Azadirachta indica seed protein hydrolysate (AIPH). The evaluation included the impact on the growth metrics, economic efficiency, antioxidant potential, hemato-biochemical indices, immune response, and histological architectures. A total of 250 fish were randomly distributed in five treatments (n = 50) and received diets included with five levels of AIPH (%): 0 (control diet, AIPH0), 2 (AIPH2), 4 (AIPH4), 6 (AIPH6)or 8 (AIPH8), where AIPH partially replace fish meal by 0, 8.7%, 17.4%, 26.1%, and 34.8%, respectively. After the feeding trial, a pathogenic bacterium (Streptococcus agalactiae, 1.5 × 108 CFU/mL) was intraperitoneally injected into the fish and the survival rate was recorded. The results elucidated that AIPH-included diets significantly (p < 0.05) enhanced the growth indices (final body weight, total feed intake, total body weight gain,and specific growth rate) and intestinal morpho-metrics (villous width, length, muscular coat thickness, and goblet cells count) in comparison to the control diet, with the AIPH8 diet recording the highest values. Dietary AIPH inclusion significantly improved (p < 0.05) the economic efficacy indicated by reduced feed cost/kg gain and increased performance index. The fish fed on the AIPH diets had noticeably significantly higher (p < 0.05) protein profile variables (total proteinsand globulin)and antioxidant capabilities (superoxide dismutase and total antioxidant capacity) than the AIPH0 group. The dietary inclusion of AIPH significantly (p < 0.05) boosted the haematological parameters (haemoglobin, packed cell volume %, and counts of red blood cells and white blood cells) and immune indices (serum bactericidal activity %, antiprotease activity, and immunoglobulin Mlevel) in a concentration-dependent manner. The blood glucose and malondialdehyde levels were significantly (p < 0.05) lowered by dietary AIPH (2%-8%). The albumin level and hepatorenal functioning parameters (aspartate aminotransferase, alanine aminotransferase, and creatinine) were not significantly (p > 0.05) altered by AIPH diets. Additionally, AIPH diets did not adversely alter the histology of the hepatic, renalor splenic tissues with moderately activated melano-macrophage centres. The mortality rate among S. agalactiae-infected fish declined as dietary AIPH levels rose, where the highest survival rate (86.67%) was found in the AIPH8 group (p < 0.05). Based on the broken line regression model, our study suggests using dietary AIPH at the optimal level of 6%. Overall, dietary AIPH inclusion enhanced the growth rate, economic efficiency, health status, and resistance of Nile tilapia to the S. agalactiae challenge. These beneficial impacts can help the aquaculture sector to be more sustainable.

Single cell protein from methanotrophic bacteria as an alternative healthy and functional protein source in aquafeeds, a holistic approach in rainbow trout (Oncorhynchus mykiss) juveniles

Bacterial single cell protein (BSCP) obtained from methanotrophic bacteria was tested as an alternative protein source to fishmeal (FM) in compound diets for rainbow trout (Oncorhynchus mykiss) juveniles (initial body weight, BW = 11.3 ± 0.2 g, mean ± standard deviation). Different levels of FM replacement (0, 25, 50, 75 and 100%) by a BSCP (0, 3.75, 7.5, 11.25 and 15% of Uniprotein® Aqua) were tested in isoproteic (crude protein: 42%) and isolipidic (crude fat: 21%) extruded diets. The trial was divided in two different parts, a nutritional trial that lasted 83 days during which the impact of experimental diets was evaluated in terms of key performance indicators (KPIs) associated to fish growth performance and feed utilization, which was followed by a challenge with a pathogenic bacterium (Aeromonas salmonicida subsp. salmonicida) to evaluate the immunological competence of fish fed the experimental diets (15 days). At the end of the nutritional trial, somatic growth in terms of body weight (BW) responded quadratically (P < 0.05) to the dietary inclusion of BCSP with the lowest BW values (183.4 ± 4.5 g) recorded in fish fed 100% FM replacement with BSCP, whereas the rest of dietary groups showed similar BW values (191.3–201.2 g). Feed intake was not affected by the level of FM replacement by BSCP, whereas feed conversion ratio (FCR) slightly increased with increasing levels of BSCP (P < 0.05), even though the lowest FCR values were found in fish fed 50% FM replacement by BSCP (0.79 ± 0.01) in comparison to the control group (0.81 ± 0.01). When using quadratic linear regression, the optimal dietary FM replacement by BSCP in terms of BW values was estimated as 41.7%. The nutritional quality of the fillet was not altered with experimental diets; all dietary groups showed similar amino acid levels as well as their content in HUFA n-3 and n-6 that remained unaltered (P > 0.05) and lipid nutritional indexes (P > 0.05). No negative effects were observed in the histological organization of the liver nor the proximate intestine, neither in the lipid peroxidation levels nor activity of antioxidative stress enzymes in the liver from fish fed increased inclusion levels of BSCP (P < 0.05). The replacement of FM by the tested BSCP obtained from methanotrophic bacteria did not cause an imbalance or dysbiosis in the intestinal microbiota in rainbow trout regardless of the level of FM replaced. The replacement of FM by BSCP at 50% improved disease resistance in rainbow trout exposed to furunculosis when compared to the control diet (cumulative mortality = 83.3 ± 7.2% vs. 49.2 ± 15.6%; P < 0.05), which suggested that this ingredient may also have some immunomodulatory properties that would protect fish from infections, although their mode of action deserves further attention. Current results indicated that the tested BSCP from methanotrophic bacteria is a safe, functional, and sustainable alternative protein source for aquafeeds.

Genetic Identification and Traceability of Insect Meals.

Insects have been proposed as a rich alternative source of protein for the partial or total replacement of fishmeal in aquaculture. For maximum safety and effectiveness of insect meals, control of the quality composition of these products is considered mandatory. The aim of this study was the genetic analysis of the composition of commercially available insect meals at the species level. Commercially available Hermetia illucens, Tenebrio molitor and Musca domestica individuals, as well as nine insect meals produced from these species, were analyzed. The genetic identification of insects at the species level was based on a COI fragment, and analysis of the insect meals' composition was performed with the processes of cloning and colony PCR. Genetic analysis indicated that the commercially available larvae morphologically identified as Musca domestica belonged to the species Muscina stabulans. In the commercially available insect meals, no other animal species was identified beyond the expected one. However, in the insect meal produced for research purposes, fungal growth was detected. The used methodology, herein, allows for the qualitative genetic identification of insect meals and could be included in the methods of traceability of products containing insects and other animal species.