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The aim of the present work was to investigate the influence of fasting and refeeding on body condition, gut physiology and microbiota in reared O. mykiss. Ninety-six fish were randomly allotted among three groups subjected to different feeding plan: C (control, fed for 5 weeks); R (restricted ration over 3 weeks followed by 2 weeks feeding); F (fasted over 3 weeks followed by 2 weeks feeding) in a well’s fresh water flow-through rearing plan. Sampling occurred at 0, 1, 2, 4, 7, 14 days during the refeeding period. At day 0 and throughout the feeding period until day 14, the weight of the fish was significantly affected by the feeding restriction. Feed deprivation reduced significantly the viscerosomatic and hepatosomatic indexes. Brush border membrane enzymes’ specific activity was modulated by feeding regimes until day 7, to level in all experimental groups at day 14. At the end of the restricted/fasted period, the microbiota of the C group was made up of 70% of Actinobacteria, 24% of Proteobacteria, 4.2% of Firmicutes and

The production of insects on an industrial scale has attracted the attention of the research and agricultural industry as novel protein sources. To detect the presence of Gryllodes sigillatus (GS) in feed and food, a real-time PCR method based on the mitochondrial cytochrome b (CYB) gene is proposed by this study. Forty DNA samples of animal and plant origin were used to confirm the specificity of the qPCR system. The detection method’s performance was evaluated on different processed GS matrices including native GS (UnGS) and different commercial products: crunchy roasted samples (RoGS), insect meal mixtures (ACGS) and energetic snacks containing GS (GSS). Data on sequencing were aligned with the reference gene to confirm the PCR products. The regression curve (y = −3.394 x + 42.521; R2 = 0.994, d.f. 14) between Ct values and Log DNA concentrations of Gryllodes sigillatus resulted in an efficiency of 96.4%. The severity of the technological processing treatments and the matrix structure affected the intensity of the PCR signal with the same amount of insect DNA as observed by different y-intercepts of the three-regression lines for RoGS, ACGS, and GSS. The real-time PCR method resulted in robust and sensitive outcomes able to detect low amounts of GS DNA (5 g/100 g) in a complex matrix, making it suitable for detecting the presence or absence of labeled Gryllodes sigillatus material both in feed and food.

One hundred twenty, 12 weeks old laying Japanese quails (JQ) were equally divided into 4 groups (6 replicates of 5 birds/group). The control group (CON) fed a corn-soybean diet; TML1.4, TML2.8, and TML5.6 groups fed a diet where a Tenebrio molitor larvae meal (TML) was included at 1.4, 2.8, and 5.6%, respectively. The trial lasted 54 days. The villi height (VH) and the crypt depth (CD) linearly decreased from the control to the TML5.6 group (P < 0.01) in the duodenum, while an opposite trend was observed for the Ab+ mucous cells count (P < 0.01). The highest VH/CD ratio was found in the TML1.4 group (P < 0.01). In the jejunum a lower VH was observed in the TML1.4 compared to the CON group; the Ab+ mucous cells increased (P < 0.01) according to the increase of the TM inclusion in the diet, while the highest VH/CD ratio (P < 0.01) was recorded in the TML2.8 group. In the duodenum only the L-ANP has been affected by TML (P < 0.001), with a quadratic and linear effect. The L-ANP is affected by the dietary treatment in the jejunum (P < 0.05), where showed a quadratic effect with the highest value in TML2.8. The % of butyric acid is maximized (P < 0.05) with the TML1.4 diet and that of the isobutyrate and valeric acids increased (P < 0.01) from TML1.4 to TML5.6. The use of TML at 1.4% in laying quail diets can be considered as a way to improve the intestinal health of the birds.

The effects of replacement of maize grain with ancient wheat by-products on intestinal morphometry and enzymatic activity in laying hens was studied. Eighty hens were divided into two groups (40 each, 8 replicates, 5 hens/replicate) fed two isoproteic and isoenergetic diets. In the treated group, part of the maize was replaced by a mix of ancient grains (AGs) middling, in a 50:50 ratio of Triticum aestivum L. var. spelta (spelt) and Triticum durum dicoccum L. (emmer wheat). The AG diet affected the weight of all the large intestine tracts, decreasing the weight of caeca (p &lt, 0.01) and increasing those of colon (p &lt, 0.01), rectum and cloaca (p &lt, 0.05). Villus height in the AG group was higher (p &lt, 0.01) than the control for the duodenum and jejunum, while for the ileum, the control group showed the highest values (p &lt, 0.01). The submucosa thickness was higher (p &lt, 0.01) in the control group for the duodenum and ileum, while the jejunum for the AG group showed the highest (p &lt, 0.05) submucosa thickness. The crypts depth was higher (p &lt, 0.01) in the control group for the duodenum and ileum. Enzyme activity was enhanced by AGs (p &lt, 0.01) in the duodenum. Regarding the jejunum, sucrase-isomaltase and alkaline phosphatase had higher activity (p &lt, 0.05 and p &lt, 0.01, respectively) in the AG group. In the ileum, sucrase-isomaltase showed higher activity (p &lt, 0.01) in the control group, while alkaline phosphatase showed the highest values (p &lt, 0.05) in the AG group. Overall, results suggested that the dietary inclusion of AGs exerted positive effects in hens, showing an improved intestinal function.

Microalgae have been used as live food in aquatic species. In recent years, the interest in microalgae has considerably increased, thanks to the evolution of production techniques that have identified them as an ecologically attractive aquafeed ingredient. The present study provides the first data about the effects of dietary inclusion of a microalgae consortium grown in a high-rate algal pond system on zootechnical performance, morphometric indices, and dietary nutrient digestibility as well as morphology and functionality of the digestive system of European sea bass,Dicentrarchus labrax. A dietary treatment including a commercial mono-cultured microalgae (Nannochloropsissp.) biomass was used for comparison. Six hundred and thirty-six European sea bass juveniles (18 ± 0.28 g) were randomly allotted into 12 experimental groups and fed 4 different diets for 10 weeks: a control diet based on fish meal, fish oil, and plant protein sources; a diet including 10% ofNannochloropsisspp. biomass (100 g/kg diet); and two diets including two levels (10% and 20%) of the microalgal consortium (100 and 200 g/kg diet).Even at the highest dietary inclusion level, the microalgal consortium (200 g/kg diet) did not affect feed palatability and fish growth performance. A significant decrease in the apparent digestibility of dry matter, protein, and energy was observed in diets including 10 and 20% of the microalgal consortium, but all fish exhibited a well-preserved intestinal histomorphology. Moreover, dietary inclusion with the microalgal consortium significantly increased the enzymatic activity of maltase, sucrase-isomaltase, and ɤ-glutamil transpeptidase in the distal intestine of the treated European sea bass. Algal consortium grown using fish farm effluents represents an attempt to enhance the utilization of natural biomasses in aquafeeds when used at 10 % as substitute of vegetable ingredients in diet for European sea bass.

The rise in the demand and the limited availability of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids claim to obtain these important long chain polyunsaturated fatty acids (LCPUFA) from novel sources. Skin of rainbow trout is a fish industry by-product but still contains valuable LCPUFA amounts with great potential applications in human nutrition and health. This study aimed to explore the nutritional composition of rainbow trout skin for its use as source of n-3 LCPUFA and its composition modification according to fish diet. Rainbow trout were fed three diets including increasing substitution levels of fishmeal with full-fat black soldier fly (Hermetia illucens) larvae meal (0%, 25%, 50% substitution levels) over 98 days. DHA was the major representative of the n-3 LCPUFA in the skin of all dietary groups, being the H25 group the richest in this fatty acid. The present study shows that the skin of rainbow trout can be a promising source of n-3 LCPUFA. Reusing the skin of farmed fish represents a possible way to decrease food industry by-products, to reduce n-3 LCPUFA shortfall and could lead to the development of functional foods and nutritional supplements including n-3 LCPUFA from fish skin.

Over the last years, the potential use of Black Soldier Fly meal (BSF) as a new and sustainable aquafeed ingredient has been largely explored in several fish species. However, only fragmentary information is available about the use of BSF meal-based diets in sturgeon nutrition. In consideration of a circular economy concept and a more sustainable aquaculture development, the present research represents the first comprehensive multidisciplinary study on the physiological effects of a BSF diet during sturgeon culture in an aquaponic system. Siberian sturgeon (Acipenser baerii) juveniles were fed over a 60-days feeding trial on a control diet (Hi0) and a diet containing 50% of full-fat BSF meal respect to fish meal (Hi50). Physiological responses of fish were investigated using several analytical approaches, such as gas chromatography-mass spectrometry, histology, Fourier Transformed Infrared Spectroscopy (FTIR), microbiome sequencing and Real-time PCR. While aquaponic systems performed optimally during the trial, Hi50 group fish showed lower diet acceptance that resulted in growth and survival reduction, a decrease in hepatic lipids and glycogen content (FTIR), a higher hepatic hsp70.1 gene expression and a worsening in gut histological morphometric parameters. The low feed acceptance showed by Hi50 group sturgeon highlighted the necessity to improve the palatability of BSF-based diet designed for sturgeon culture.

The aim of this study was to evaluate nutrient digestibility, growth response, carcass and fillet yields, muscle tissue composition and skin colour appearance of European sea bass (D. labrax) fed graded levels of a mixture of Tisochrysis lutea and Tetraselmis suecica freeze-dried biomass in partial substitution for fish meal and oil in diets containing substantial levels of vegetable oils and protein-rich derivatives. Five complete diets were formulated to be grossly isoproteic and isolipidic and prepared by including a blend of the two freeze-dried microalgae biomass in a 2:1 weight ratio, to replace approximately 15, 30 and 45% fish meal protein and 12, 24 and 36% fish lipid of a positive control diet. A negative control complete feed high in soybean meal was also prepared. Each diet was offered in triplicate, during 105 days until visual satiety of fish (204 ± 12.7 g) kept in a semi-closed recirculating marine water system ensuring optimal water quality to E. sea bass. The results of the study have shown that replacing about 45% crude protein and 36% lipid from fish meal and lipid by a mixture of Tisochrysis lutea and Tetraselmis suecica dried biomass, did not adversely affect growth performance and feed conversion efficiency of European sea bass. A slight decline in dry matter, protein and energy digestibility occurred in response to graded levels of dietary microalgae biomass, which was compensated by increased feed intake. Moreover, the diet including the dried microalgae resulted in a higher nutritive value than that of the negative high-soybean meal control feed. No major changes were observed in biometry traits and slaughter yield while the nutritional properties of the edible muscle tissue were little affected in terms of n-3 PUFA. The presence of the dried microalgae in the diet resulted in a greenish pigmentation of the skin, with a slight tendency towards redness and diminished lightness and hue. Overall the results obtained here reveal a potential improvement in sustainability in terms of reduced reliance on halieutic feed resources in case of the microalgae-containing diets. Hence the sustainable use of the dried mixture of the 2 marine microalgae biomass as feed ingredients in diets for the E. sea bass seems to be mainly limited by the low availability and unaffordable market price which are both expected to improve over the next 10 years.

Despite a growing interest in microalgae and cyanobacteria as potential sources of nutrients in aquafeeds, little information is presently available on their nutritive value for carnivorous fish species. The aim of this study was to evaluate chemical composition and nutrient digestibility of a panel of microalgae and cyanobacteria dried biomasses (MACB), using rainbow trout (Oncorhynchus mykiss W.) as a fish model. Nine test diets were obtained by mixing 80 parts of a reference diet, added with 20 g/kg of acid insoluble ash as an indigestible marker, to 20 parts of each of the following dried whole-cell biomass: Arthrospira platensis, Nostoc sphaeroides, two strains of Chlorella sorokiniana, Nannochloropsis oceanica, Tisochrysis lutea, Phaeodactylum tricornutum, Porphyridium purpureum and Tetraselmis suecica. The digestibility measurements were conducted with rainbow trout (52.4 ± 1.5 g) kept in six tank units each including three 60-L vessels singularly stocked with 12 fish and fitted with a settling column for faecal recovery. Per each diet, faeces were collected over three independent 10-day periods. Apparent digestibility coefficients (ADCs) of dry matter, crude protein (CP), organic matter and gross energy (GE) of single MACB were calculated by difference relative to those of the reference diet. The MACBs had heterogeneous chemical composition (CP, from 20 to 69%; Lipid, 5-27%; GE, 12.5--22.6 MJ/kg dry matter basis) reflecting their overall biodiversity. Most of them can be considered as virtually good sources of minerals and trace elements and exhibit an essential amino acid profile comparable or even better than that of soybean meal commonly used in fish feeds with P. purpureum showing the best protein profile. The digestibility results obtained with rainbow trout allowed ranking the MACBs into two major groups. A first one, including C. sorokiniana, N. oceanica and T. suecica, resulted in markedly lower (P < 0.05) crude protein and energy ADC (64-73%; 51-59%, respectively) compared to a second group including P. purpureum, T. lutea and cyanobacteria (CP-ADC, 83-88%; GE-ADC, 74-90%) while P. tricornutum resulted in intermediate values. Overall, the present study confirms the consistently reported role of cell-wall structure/composition in affecting accessibility of nutrients to digestive enzyme. Based on the overall outcomes, only T. lutea and cyanobacteria actually meet the requirements for being used as protein sources in aquafeeds provided their mass production becomes more feasible and cost-effective, hence attractive for the feed-mill industry in the near future.

Black Soldier Fly (BSF) meal is considered as an alternative, emerging and sustainable ingredient for aquafeed production. However, results on fish physiological responses are still fragmentary and often controversial, while no studies are available on fish behavior in response to these new diets. The present work represents the first comprehensive multidisciplinary study aimed to investigate zebrafish physiological and behavioural responses to BSF-based diets. Five experimental diets characterized by increasing inclusion levels (0, 25, 50, 75 and 100% respect to fish meal) of full fat BSF prepupae meal were tested during a 2-months feeding trial. Prepupae were cultured on coffee silverskin growth substrate enriched with a 10% Schizochytrium sp. to improve insects’ fatty acids profile. The responses of zebrafish were assayed through biometric, histological, gas chromatographic, microbiological, spectroscopic, molecular and behavioural analyses. Results evidenced that BSF-based diets affected fish fatty acid composition, while behavioural tests did not show differences among groups. Specifically, a 50% BSF inclusion level diet represented the best compromise between ingredient sustainability and proper fish growth and welfare. Fish fed with higher BSF inclusions (75 and 100%) showed hepatic steatosis, microbiota modification, higher lipid content, fatty acid modification and higher expression of immune response markers.

Promoting circularity in the aquaculture sector through the conversion of great amount of organic by-products produced on land is a valuable strategy for a further development of the aquaculture sector. In this regard, insects represent a very promising example of bio-converting organisms; their application in aquafeeds, however, still faces possible limitations because of their lack in polyunsaturated fatty acids and the presence of chitin. The aim of the present study was to apply circularity to Black Soldier Fly (BSF) (Hermetia illucens) culture and to improve the insect's biomass fatty acid composition by culturing them on a land-produced by-product (coffee silverskin) enriched with a 10% Schizochytrium sp. The insect biomass was then used to formulate five fish diets containing 0, 25, 50, 75 and 100% of insect meal respect to fish meal, respectively. Diets were used for a feeding trial during zebrafish (Danio rerio) larval development (21 days) and a multidisciplinary approach including biometry, histology, gas chromatography, spectroscopy (FTIR), microbiota analyses and molecular biology was applied to better understand fish responses to the new diets. Results showed that the 50% substitution of fish meal with insect meal represented the best compromise between ingredient sustainability and proper fish growth and welfare. Fish fed with higher BSF inclusions (75 and 100%) showed a severe degree of hepatic steatosis, microbiota modification, a higher lipid content (FTIR), fatty acid modification and higher expression of both stress and immune response markers.

Gracilaria gracilis and Nannochloropsis oceanica, single or blended, were tested in European seabass (Dicentrarchus labrax) diets. A control (CTRL) diet was compared with experimental diets including either 8% G. gracilis (GRA8), 8% N. oceanica (NAN8), or a blend of 4% of each alga (NAN4GRA4). After 106 days of feeding, growth, nutrient utilization, antioxidant defense, immunological status, and end-product quality were evaluated. All fish exhibited similar feed intake (1.4–1.5%), body weight, growth, and feed conversion ratio (1.6). Dietary inclusion N. oceanica did not affect digestible N intake and gain. Fish fed GRA8 had the lowest digestible N and energy intake (P

Insects are able to bio-convert organic by-products into a sustainable biomass for aquafeed formulation. Specifically, among several insect species, Hermetia illucens (H) is particularly interesting for its nutritious traits but, unfortunately, the lipidic fraction is poorly represented by polyunsaturated fatty acids n-3 and poses some limits in its application in aquafeed formulation. The present study undertook an interdisciplinary approach to explore the effects of three experimental diets containing increasing levels of full-fat H meal (H0 diet based on fishmeal and purified protein-rich vegetable ingredients; H25 and H50 diets containing 25% or 50% of full-fat H meal replacing fishmeal, respectively), on rainbow trout (Oncorhynchus mykiss) fed over a 98 days experimental period. The expression of genes related to lipid metabolism by RT-qPCR, liver histology, as well as the qualitative traits of fillets and fatty acid (FA) composition were investigated. Interestingly, fads2 gene expression in pyloric caeca increased in fish fed diets containing the highest full-fat H meal inclusion (H50 > H0; p The overall results showed that the dietary full-fat H meal inclusion under study did not impair fish fillet quality, guaranteeing its nutritional value. Some effects on lipid metabolism were observed, as suggested by liver, pyloric caeca and mid intestine gene expression and liver FA profile. Future studies on the biological mechanisms behind the macroscopic traits of fish fed unprocessed insects are warmly encouraged.

The expected future demand for highly nutrient animal food products will push the animal production system to search for new sources of high-quality protein feedstuffs. In this scenario, economic and environmental issues will have to be considered while reducing the competition with the plant-based human food chains. Legume grains and some oilseed cakes, by-products from the oil industry, are the main protein sources for ruminants and terrestrial monogastrics such as pigs and poultry. Their relevant role will hold in the next decades, but it is necessary to increase the diversification of sources that can be grown profitably throughout the world, including European countries. Microalgae are a promising source of protein and other nutrients for animal feeding. However, an amazing richness of biologically active substances makes these organisms very interesting as feed ingredients, as their role go far beyond the supply of nutrients. Due to the limited usage of microalgae as human foodstuffs or food ingredients, low competition between microalgae-based feed and food chains is predictable. This review aims to synthesise current knowledge on minor pulses and other protein-rich plant products and microalgae, as alternative ingredients to the conventional animal protein sources, focussing on their production, availability, and nutritional values. Points of strength, weakness, opportunity and threat related to the use of these protein sources in animal feeding are separately analysed through a SWOT approach to underlie future needs in terms of research and/or technological development that could help valorise these nutrient sources as feed ingredients.

Algae are natural sources of nutrients, but the presence of anti-nutritional factors often compromises nutrient apparent digestibility coefficients (ADCs) in several fish species. In this study, physical-mechanical and enzymatic technological processing was applied to two seaweeds (Gracilaria gracilis and Ulva rigida) and three microalgae (Nannochloropsis oceanica, Chlorella vulgaris, and Tetraselmis sp.) in order to evaluate its effectiveness in improving nutrient ADC values in diets for European seabass. A practical commercial-based diet was used as reference (REF) and experimental diets were prepared by replacing 30% of REF diet with each test alga used either intact or after processing. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fast performance liquid chromatography (FPLC) analyses revealed that enzymatic processing was more effective than the physical one in changing the protein and peptides composition, increasing the amount of low-molecular-weight compounds in seaweeds and N. oceanica microalgae. Protein digestibility was significantly affected by algae species and in the case of the microalgae by the technological process. Gracilaria gracilis is better digested than U. rigida and physical processing enhanced protein and energy ADC values. Nannochloropsis oceanica and C. vulgaris are better digested than Tetraselmis sp.; the highest protein and energy ADCs were observed in diets containing enzymatically processed N. oceanica (NAN-ENZ) and physically processed C. vulgaris (CHLO-PHY), followed by the diet with physically processed Tetraselmis sp. (TETR-PHY). Results clearly showed that it is possible to increase nutrient accessibility and digestibility of algae by fish, by selecting the most adequate method to disrupt the cell wall. Moreover, the physical-mechanical and enzymatic technological processes used in this study are scalable to the industrial level.

In a preliminary in vitro study, a Panax ginseng extract exhibited an evident antibacterial activity against Yersinia ruckeri and Lactococcus garvieae and affected the respiratory burst and proliferation of rainbow trout Oncorhynchus mykiss leukocytes. Subsequently, the effects of a dietary ginseng extract supplementation on growth, blood biochemical profile, innate immune response and resistance against Y. ruckeri infection were investigated in vivo in rainbow trout juveniles. Four experimental diets were obtained by adding 0.0%, 0.01%, 0.02%, 0.03% of ginseng ethanolic extract to a commercial feed. Each diet was fed to triplicate groups of fish (mean body weight 30.5 ± 0.15 g) at 1% of body weight day−1 for 10 weeks. The dietary supplementation with ginseng extract did not affect growth performance, feed utilization, biometric traits and fish whole body composition (P > 0.05). No major changes due to graded levels of ginseng extract in the diet were observed in blood biochemical parameters except for increasing plasma triglycerides and non-esterified fatty acids in fish fed diets including 0.01% and 0.02% of extract (P 0.05). The dietary administration of ginseng extract induced a reduction in mortality of rainbow trout infected with Y. ruckeri, although no significant differences between treated and control groups were observed (P > 0.05).

Recently, the insects meal has been released by the European Union as an ingredient in aquafeeds and only seven insect species have been allowed to be used for these preparations. To avoid misleading results, a suitable method for the detection of these insect species in food/feed, would be highly desirable. In this paper, we present an innovative, sensitive, specific and low-cost Point-of-Care apparatus, based on DNA probes for the detection of one of the most popular insects used in aquafeed preparation, Hermetia illucens (HI), commonly known as black soldier fly. The DNA probes adopted for this genosensor have been designed to enable a very specific insect recognition which were derived from DNA primers. The DNA primers were first tested with qPCR. Forty different samples (animal species and common aquafeed ingredients) have been tested to check the possible cross-reactivity, confirming the adequate primers specificity. The primers have been used in a practical application, like the detection of HI in complex matrices of practical aquafeeds. The DNA probes derived by these primers have been then applied to implement an Organic Light Emitting Diode (OLED) based genosensor. The developed genosensor has been tested with HI DNA directly extracted from the insect, without any DNA amplification; a good test sensitivity has been obtained, being 0.75 ng/μl its detection (LOD) limit. Then, the genosensor has been tested with the DNA extracted from the same aquafeeds used in the qPCR experiments. The results obtained by these two methods have then been compared giving very good consistency and both allowed to detect HI meal up to a minimum threshold of 5 g/100gr feed.

To evaluate the effects of feeding a Hermetia illucens (HI) larvae meal on the different intestinal traits of hens, and to determine the toxic elements&rsquo, concentration in the insect meal and diets, 162 hens were randomly allotted to three groups. The control received a corn-soybean meal-based diet (SBM), the HI25 and HI50 groups received two diets in which the 25% and 50% of the dietary protein were replaced by the HI protein, respectively. The duodenal and jejunal villi height and villi/crypt were higher (p &lt, 0.01) in the SBM than in the HI groups. The ileal villi height was higher (p &lt, 0.05) in the SBM and HI25 groups than the HI50. The HI50 group exhibited a lower duodenal maltase activity. The intestinal alkaline phosphatase (IAP) activity linearly decreased in the duodenum and jejunum as the dietary insect meal inclusion increased. The HI50 group had a higher acetate and butyrate level than the SBM. The levels of cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As) in the diets and insect meal were lower than the maximum values established by the EU Commission. The 25% soybean protein replacement with Hermetia illucens larvae meal in the diet of laying hens was more suitable and closer to the optimal level than 50%.

Intensive fish farming relies on the use of feeds based on fish meal and oil as optimal ingredients; however, further development of the aquaculture sector needs new, nutritious and sustainable ingredients. According to the concept of circular economy, insects represent good candidates as aquafeed ingredients since they can be cultured through environmental-friendly, cost-effective farming processes, on by-products/wastes, and many studies have recently been published about their inclusion in fish feed. However, information about the physiological effects of insect-based diets over the whole life cycle of fish is presently missing. At this regard, the present study investigated, for the first time, the effects of Black Soldier Fly based diets (25 and 50% fish meal substitution) administration for a six months period in zebrafish (Danio rerio), from larvae to adults. A multidisciplinary approach, including biometric, biochemical, histological, spectroscopic and molecular analyses was applied. Aside a general reduction in fish growth and lipid steatosis, six-months feeding on Black Soldier Fly based diets did not show major negative effects on zebrafish. Gut histological analysis on intestine samples did not show signs of inflammation and both stress markers and immune response markers did not show significant differences among the experimental groups.

The aim of this study was to evaluate nutrient digestibility, growth performance, biometry, dressing out parameters, fillet muscle proximate and fatty acid composition of European sea bass (Dicentrarchus labrax, L.) of nearly marketable size, fed increasing levels of a freeze-dried biomass of Isochrysis sp. (clone T-ISO) as a partial substitute for protein and lipid from fish derivatives, in diets where the level of n-3 long chain (LC) PUFA were reduced through a partial replacement of fish oil for crude palm oil. Since diets including the test ingredients could possibly result in changes of certain quality attributes, fish were also subjected to overall sensory evaluation by a trained panel of assessors according to a triangle test. Three diets were formulated to be grossly iso-nitrogenous (N, 7.5 % dry matter). A preparation in which fish meal/trimmings and fish oil were the major protein and lipid sources was used as a positive control diet. Two test complete diets were obtained from the control preparation so that approximately 10 and 20% crude protein from a high quality fish meal and 18 and 36% lipids from fish oil were supplied by the dried microalgae biomass. To stress the role of Isochrysis sp. as a source of n-3(LC)PUFA, the diets including increasing levels of the microalgae biomass were made grossly iso-caloric-lipidic by replacing a part of fish oil with palm oil which is known to be virtually free from n-3 PUFA. Each diet was fed to apparent satiety to quadruplicate groups of sea bass (142 g) over 121 days. The results have shown that replacing up to 20% crude protein from fish meal with a dried Isochrysis biomass and up to 36% fish lipid for those supplied by the microalgae in a diet with reduced level of fish oil, did not adversely affect feed intake or growth performance relative to controls even if the highest substitution rate resulted in a decline (P

A desirable goal of the aquaculture sector is to replace most of fish meal and fish oil with more sustainable, cost-effective, and environmental friendly ingredients ensuring fish health and welfare standards. Due to minimal environmental impact, compared with most conventional feed commodities, insects deserve a growing attention as candidate ingredients for aquafeeds. The present study investigated, for the first time, the possible application of a 100% insect diet in zebrafish larval rearing. Through a multidisciplinary approach, the major biological responses of fish to the new diets were assessed. Results of biometry, fatty acid composition, expression of genes involved in fish growth, stress response, lipid metabolism, chitinolytic activity, gut inflammation, and liver macromolecular composition suggested a possible application of insect larvae for zebrafish larval rearing. However, further studies are necessary to better understand the use of this insect species in the rearing of fish.

This research investigated the ileum morphometry and enzymatic activity, the caecal volatile fatty acid production and the apparent nutrient digestibility in laying hens fed a Hermetia illucens larvae meal (HILM) as a complete replacement of diet soybean meal (SBM). The hens fed HILM exhibited a lower live weight (P < 0.05) and a higher incidence of the full digestive tract (P < 0.05) than the SBM group. In the duodenum, the maltase exhibited a higher (P < 0.05) activity in the HILM group while the intestinal alkaline phosphatase (IAP) had a higher (P < 0.05) activity in the SBM group. In the ileum, the maltase and saccarase had a higher activity in the HILM hens (P ≤ 0.01) while the IAP and ɤ glutamil transferase had a higher activity in the SBM group (P < 0.05 and P < 0.01, respectively). The HILM group showed a higher (P < 0.05) villi height in the duodenum, while the opposite happened in the jejunum and the ileum. Only in the ileum the crypt depth resulted higher (P < 0.05) in the HIML group than in the SBM. The higher production of acetate (P < 0.05) and butyrate (P < 0.01) affected the total production of volatile fatty acids of the HILM group. The coefficient of apparent digestibility of dry and organic matter as well as of crude protein was higher (P < 0.05) in SBM group. The total replacement of SBM with HILM in laying hens diet from 24 to 45 weeks of age resulted in a higher caecal production of butyric acid while the enzymatic activities of brush border membrane were partially reduced.

Due to minimal environmental impact, compared to most conventional feed commodities, insects deserve a growing attention as candidate ingredients for aquafeeds. This study tested, for the first time during zebrafish larval rearing, the effects of an increasing replacement (0%-25%-50%) of fish meal by black soldier fly (BSF) full-fat prepupae meal. All diets were formulated to be isonitrogenous and isolipidic. A multidisciplinary approach, including biometrics, histology, gas chromatography-mass spectrometry, and molecular analyses, was applied to better understand the biological responses of larval zebrafish to the different partial inclusions of BSF in the feed. Generally, results are promising, but a 50% of BSF meal inclusion in the diet affected both lipid composition and accumulation in the larvae.

The dietary methionine (Met) and total sulfur amino acid (TSAA) requirements of European sea bass (Dicentrarchus labrax) (initial body weight 13·4 (sd 0·2) g) were estimated in a 12-week dose–response experiment. Seven isonitrogenous (7·6 % DM) and isoenergetic (gross energy, 21·2 MJ/kg DM) diets, based on soya protein and crystalline l-amino acids containing graded levels of l-Met (1·6–16·2 g/kg) at a constant cysteine (4 g/kg) level and a fish meal-based diet, were fed each to triplicate groups of fifty fish kept in 250 litre tanks in a thermoregulated (23 ± 0·5°C) seawater system. The Met and TSAA-deficient diet resulted in higher mortality, impaired feed intake and growth relative to the other treatments (P 0·75 per d, which represents 23 % of the total (maintenance+accretion) requirement.

European anchovy Engraulis encrasicolus, with total lengths ranging from 40·0 to 132·5 mm, were sampled during October 2002 and May 2003 in the northern Adriatic Sea in order to estimate their energy densities (E D ). A highly significant (P < 0·001) relationship between E D (y) (J g -1 wet mass) and per cent dry mass (x) was found: y = 321x - 3316·9 (n = 161, r 2 = 0·82).

Two hundred and twenty rainbow trouts (IBW: 700 g) were randomly allotted to four tanks, with a male/female ratio of 0.56. Fish were fed for 168 d with four experimental diets containing herring oil, cod liver oil and coconut oil with the following inclusion rates: diet A: 12-1-0% respectively; diet B: 6-1-6%; diet C: 0-1-12%; diet D: 0-0-13%. Irrespective of the dietary treatment, weight gains of broodstocks were high (> 3 g/d) and FCR below 2. No significant difference was observed concerning the total amount of eggs spawn, egg average weight (82.5 mg/egg) and lipid content (5.4 mg/egg). However, the fatty acid profile of eggs was significantly affected by the dietary treatments. The content of unsaturated fatty acids, particularly the n-3 fatty acid series (EPA and DHA) significantly decreased with increasing levels of coconut oil in the diet.

In the current study, two different slaughtering procedures, spiking vs immersion in water/ice slurry, were applied on electrically stunned European sea bass (Dicentrarchus labrax) and the effects on actin degradation and fillet quality attributes were investigated. Rigor mortis index was similar for the two slaughtering techniques, whereas the shear force measurement indicated that rigor mortis occurred more quickly and intensely in the water/ice handled fish than in those slaughtered by spiking. The water/ice immersion procedure also resulted in higher amount of actin fragments than spiking. Muscle tissue apparent viscosity and water holding capacity were lower in sea bass treated in water/ice slurry compared with fish handled by spiking, whereas the acidification patterns of the two groups were not easily distinguishable. In conclusion, spiking appeared to preserve actin integrity better that water/ice and it seemed to ensure less muscle damage as indicated by the higher viscosity and water holding capacity values. Finally, a role of actin as a biochemical marker for the prediction of fish quality was suggested.

Nutritional quality parameters, microbiological and technological quality indicators (condition index, meat yield and water-holding capacity) of blue mussel, Mytilus galloprovincialis , reared in the North Adriatic Sea were characterised at monthly intervals over a 1 year period. Contents of protein (7.5–11.6 g/100 g), lipid (1.0–2.2 g/100 g) and ash (2.2–3.3 g/100 g) varied significantly accordingly to condition index (6–15%). n-3 PUFAs were the predominant fatty acids (38.7–45.9% of fatty acids) and docosahesaenoic and eicosapentaenoic acids were the most abundant (167 and 93.3 mg/100 g, respectively). Glycine, glutamic and aspartic acids accounted for 40% of total amino acids. All samples exhibited limited concentrations of Cr, Mn, Ni, Cu and Zn, as well as Na. M. galloprovincialis from the North Adriatic Sea showed the highest technological and nutritional quality, considering also the inter-annual variability, in late spring, which corresponds to the period immediately before gamete release.

Previuos investigations have shown wheat gluten meal (WGM) to be a promising candidate ingredient to replace fish meal (FM) in sea bass diets, based on its high crude protein content and biavailability and the absence of antinutritional factors in the raw material (Robaina et al., 1999; Tulli and Tibaldi, 2001)...

Considering the well-known problems arising from the use of rotifers and Artemia as live prey in larval rearing in terms of fatty acid deficiencies, the aim of this study was to evaluate a partial or complete replacement of traditional live prey with preserved copepods during the larviculture of gilthead sea bream (Sparus aurata). Sea bream larvae were randomly divided into 4 experimental groups in triplicates: group A larvae (control) fed rotifers followed by Artemia nauplii; group B fed a combined diet (50%) of rotifers–Artemia and preserved copepods; group C fed rotifers followed by preserved copepods; and group D fed preserved copepods solely. Survival and biometric data were analysed together with major molecular biomarkers involved in growth, lipid metabolism and appetite. Moreover, fatty acid content of prey and larvae was also analysed. At the end of 40 days treatment, a stress test, on the remaining larvae, was performed to evaluate the effects of different diets on stress response. Data obtained evidenced a positive effect of cofeeding preserved copepods during sea bream larviculture. Higher survival and growth were achieved in group B (fed combined diet) larvae respect to control. In addition, preserved copepods cofeeding was able to positively modulate genes involved in fish growth, lipid metabolism, stress response and appetite regulation.