Replacement Of Fish Meal Research Articles

Balanced replacement of fish meal with Hermetia illucens meal allows efficient hepatic nutrient metabolism and increases fillet lipid quality in gilthead sea bream (Sparus aurata)

In the present study, gilthead sea bream (Sparus aurata) was reared using sustainable feeds containing insect meal from Hermetia illucens larvae. Proteomics and proton nuclear magnetic resonance-based metabolomics analysis were used to assess the metabolic impact of the tested feeds in sea bream liver, whereas the composition of muscle fillets was characterized by means of metabolomics and gas chromatography of fatty acid methyl esters. Including 10% of insect meal while correspondingly reducing fish meal did not substantially alter the metabolism of dietary nutrients, leading to small but significant effects solely on lauric acid content of sea bream fillets. Furthermore, a few alterations in some markers of immune response, such as leukocyte elastase inhibitor-like, granzyme B (G, H)-like, and two associated ortholog groups, serpin B and chymase, were found. In the fish group fed with insect meal, liver morphology analysis showed no structural damage or inflammation and a lower amount of hepatic lipid deposition and accumulation.

Salmon hydrolysate as a protein source for Atlantic salmon; prion content and effects on growth, digestibility and gut health

Feeding unhydrolyzed protein to the same species from which it came from have caused prion disease in some mammals, but this has not been observed in fish. In this study, we characterized a salmon protein hydrolysate (FPH) for prion content and investigated how partially replacing fish meal with salmon hydrolysate, affected growth, digestibility and gut health of Atlantic salmon (Salmo salar). The salmon hydrolysate was analysed for prion content by shotgun and targeted proteomics, but no prions were found. Atlantic salmon post smolts were fed one of the following: a control diet containing 30% fish meal (FM), a 20% FM with 9% salmon hydrolysate diet (FPH-09) or a 10% FM with 18% salmon hydrolysate diet (FPH-18). Salmon fed the hydrolysate diets had higher specific growth rate over the first 25 days. The FPH-18 diet contained more digestible proteins and amino acids than the FM diet, and the ash digestibility increased linearly with the FPH content, indicating increased mineral uptake. Histological analysis of midgut and hindgut did not reveal any significant differences between the FM and FPH-18 diets, and the intestines were assessed to be normal and healthy. These results imply that salmon hydrolysate is a promising novel feed ingredient for Atlantic salmon, due to its excellent amino acid profile and high digestibility.

Affecting mechanism of Chlorella sorokiniana meal replacing fish meal on growth and immunity of Litopenaeus vannamei based on transcriptome analysis

The purpose of this study was to analyze the affecting mechanism of Chlorella sorokiniana meal replacing fish meal on the growth performance and immune function of Pacific white shrimp, Litopenaeus vannamei by transcriptomics analysis. In a control diet containing 560 g % /kg fish meal, chlorella was used to replace 0 %, 20 %, 40 %, 60 %, 80 % and 100 % of dietary fish meal to form six iso-nitrogenous and iso-lipidic diets (C0, C20, C40, C60, C80, C100). The six diets were fed to white shrimp (1.37 ± 0.02 g) for 8 weeks. Compared to the control group, the final body weight (FBW), specific growth rate (SGR) and feed efficiency (FE) of the C20 group were significantly improved (P < 0.05). There was no significant difference in growth performance between the C40 group and the C0 group (P > 0.05). When the replacement level of fish meal by chlorella was ≥ 60 %, the FBW, SGR and FE of shrimp were significantly decreased (P < 0.05). In the analysis of the hepatopancreatic transcriptome, the amount of differentially expressed genes (DEGs) in C20, C40, C60, C80 and C100 groups were 322 (176 up and 146 down), 482 (246 up and 236 down), 804 (487 up and 317 down), 1080 (684 up and 396 down) and 1262 (827 up and 435 down), respectively, when compared to the C0 group. GO Term and KEGG pathway enrichment analysis of DEGs showed that DEGs between the C20 and C0 groups were significantly enriched in chitin binding and inositol metabolism processes. Several immune-related signaling pathways were also enriched, including the C-type lectin receptor pathway, complement and coagulation cascades, the B-cell receptor pathway, and most of these genes were up-regulated in the C20 group. Compared to the C0 group, DEGs in C40, C60, C80 and C100 groups were significantly enriched in lysosomal, protein digestion, and absorption pathways. In addition, in the C80 and C100 groups, the DEGs were also significantly enriched in lipid catabolism process. The high replacement of fish meal with chlorella meal affected the absorption and utilization of nutrients by regulating the signaling pathways related to protein digestion and absorption, and aggravated lipid catabolism of the body, thereby affecting the growth of shrimp. The high replacement of fish meal might also affect the homeostasis of shrimp cells and reduce immunity through the lysosomal signaling pathway. In summary, the low replacement of fish meal (20 %) with chlorella meal significantly improved the growth performance of Litopenaeus vannamei, which might be realized through activating the C-type lectin receptor signaling pathway to regulate immune function of the body, but the high substitution of fish meal (≥ 60 %) reduced the growth performance and immunity by affecting the lysosomal signaling pathway.

Effects of fermented soybean meal substitution for fish meal on intestinal flora and intestinal health in pearl gentian grouper.

This study explored the role of replacing fish meal protein with fermented soybean meal (FSBM) protein on the growth performance and intestinal morphology, immunity, and microbiota of the pearl gentian grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂). Three isonitrogenous and isolipidic diets with increasing levels of FSBM (0%, 20% and 40%; referred to as FM, FSBM20 and FSBM40 diets, respectively) as a replacement for fish meal were selected for this study. The pearl gentian grouper were fed these diets for 10 weeks. The findings revealed that the growth of fish fed the FSBM diets (FSBM20 and FSBM40) were remarkably lower than the fish fed the FM diet. Pathological manifestations of intestinal inflammation, such as shortened intestinal mucosal folds and thickened lamina propria, were observed in the fish fed the FSBM diets. Moreover, the gene expression levels of IL1β, IL12, IL17, and TNFα were remarkably upregulated in fish fed the FSBM40 diet, in contrast to the gene expression levels of IL4, IL5, IL10, and TGFβ1, which were remarkably downregulated (p < 0.05). The FSBM diets significantly affected the stability of the fish gut microbiota. Photobacterium was the dominant phylum in all experimental groups, and the proportion of these bacteria gradually decreased with increasing FSBM substitution. The composition of intestinal flora at the genus level was not the same in the three experimental groups, with a richer composition of intestinal bacteria detected in the FSBM20 and FSBM40 groups (p < 0.05). The correlation between intestinal flora balance and immune gene expression revealed that only Photobacterium was negatively correlated with the above upregulated genes, while other bacteria were positively correlated with these pro-inflammatory factors (p < 0.05). Photobacterium was positively correlated with the above downregulated genes, while other bacteria were negatively correlated with these anti-inflammatory factors (p < 0.05). In conclusion, high levels of substitution of FSBM for fish meal causes intestinal inflammation in pearl gentian grouper. This is likely associated with changes to the intestinal flora. More attention should be paid to the negative role of dietary FSBM on intestinal flora.

Effects of dietary replacement of fishmeal by cottonseed meal on the growth performance, immune and antioxidant responses, and muscle quality of juvenile crayfish Procambarus clarkii

The current research was aimed to determine the impacts of cottonseed meal substitution levels for fishmeal on the growth performance, immune indices, antioxidant ability, and muscle texture of red swamp crayfish (Procambarus clarkii). Five isonitrogenous and isolipidic diets were formulated to feed the crayfish for 8 weeks. The basal diet contained 20% fishmeal (FM), while the other four experimental diets substituted fishmeal in FM diet with cottonseed meal at levels of 25%, 50%, 75%, and 100%, referred to as CM25, CM50, CM75, and CM100 respectively. A total of 750 crayfish with an average initial weight of 4.00 g were selected and randomly allocated to fifteen cages. Each diet was randomly assigned to triplicate groups of crayfish. Weight gain and specific growth rate declined, and feed conversion rate, asparate aminotransferase and alanine transaminase activities appear to increase as cottonseed meal substitution levels increased. Serum total cholesterol levels declined in crayfish fed CM100 diet compared to crayfish fed the FM diet. Serum phenoloxidase and lysozyme activities, and muscle hardness and mef-2a mRNA expression were the highest for crayfish fed fishmeal-based diet and showed no significant difference among other four groups. Dietary cottonseed meal levels did not significantly influence hepatopancreas index, viscerosomatic index, condition factor, serum glucose, triglyceride, albumin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and creatinine contents, as well as the contents of acid phosphatase, and alkaline phosphatase, and muscle texture profile (cohesiveness, springiness, adhesiveness, and chewiness) and mef-2b and mstn mRNA expression. High dietary fish meal replacement by cottonseed meal tended to upregulate mRNA expression of nuclear factor erythroid 2-related factor 2, glutathione peroxidase, glutathione reductase, manganese superoxide dismutase, glutathione S-transferase, and catalase. Taken together, dietary cottonseed meal reduced growth performance and feed utilization, induced hepatopancreas oxidative stress, and influenced some serum and muscle parameters. The gossypol content and unbalanced amino acid profile are considered the limiting factor influencing the fish meal replacement by cottonseed meal.

Tryptophan can alleviate the inhibition in growth and immunity of tilapia (GIFT Oreochromis spp.) induced by high dietary soybean meal level

A 85-day feeding trial was designed to verify the effects of soybean meal on growth, feed utilization, antioxidants, and immune response of tilapia (GIFT Oreochromis spp.), and evaluated the effects of dietary tryptophan on alleviating the negative responses induced by high inclusion of soybean meal. Five experimental diets, two of which substituted 15 % and 45 % of the fish meal with soybean meal, the others supplemented with 0.2 %, 0.4 % and 0.6 % L-tryptophan on the basis of 45 % soybean meal, respectively, were fed 400 juvenile fish (initial weight: 2.98 ± 0.04 g). The results showed that the crude ash content, red blood cell count (RBC), lipase (LPS) and glutathione peroxidase (GSH-Px) activities of tilapia significantly decreased when the soybean meal replaced fish meal by 45 % (p < 0.05). Although the growth performance values of replacing 45 % soybean meal were slightly lower than that of replacing 15 % soybean meal, while there was no significant difference between them (p > 0.05). However, supplementation with tryptophan in the high soybean meal replacement groups significantly improved the final weight, weight gain rate (WGR), specific growth rate (SGR), phagocytosis index (PI), RBC, trypsin (TPS), LPS and GSH-Px activities of tilapia (p < 0.05), and the apparent digestibility and feed coefficient of tilapia were significantly decreased (p < 0.05). Taken together, these results suggested that excessive soybean meal inhibited the feed utilization and immunity of tilapia to a certain extent, while the inclusion of 0.2 %−0.4 % tryptophan in the diet could alleviate the negative effects of high soybean meal diet in tilapia. This study will provide ideas and a theoretical basis for further expanding the application of soybean meal in tilapia feed.

Fishmeal replacement and its effects on nutrition and the physiology of Penaeus vannamei shrimp juveniles

The replacement of fishmeal with plant protein sources has been studied in Penaeus vannamei. However, it has only been studied from the point of view of protein replacement, forgetting the integral role that fishmeal plays in the nutrition of shrimp. This study aimed to determine if a supplement of dietary phosphorus can sustain the fishmeal replacement by a blend of plant protein feedstuffs, with betaine and tauren as attractants and still supporting homeostasis, growth, digestive enzymes, and lipid-soluble antioxidant systems at normal levels in juveniles of P. vannamei. A standard feed (25% fishmeal) for juvenile P. vannamei was partially replaced with a mix of plant ingredients (soybean and canola paste, soy protein concentrate, and wheat meal). These feedstuffs were supplemented with amino acids (MET, LYS, TAU) plus microencapsulated exogenous phytase, betaine, and dicalphosphate. P. vannamei juveniles (2.56 g) were maintained in 100 L fiber tanks for 70 days. Biomass was significantly affected by the treatments (P &lt; 0.05), being better as the fishmeal was replaced in the diet and comparable to commercial feed. No significant changes were observed in blood parameters. Muscle superoxide dismutase activity was significantly affected by the diets (P &lt; 0.05). There were adaptive changes in digestive enzymes, and homeostasis remained stable. Fishmeal replacement may depend on supplementation with taurine and soluble phosphorus, not only for performance but flesh quality, and here, the shear strength of the shrimp muscle remained within the acceptable value (69-81 mJ).

A review and meta-analysis of selected plant protein sources as a replacement of fishmeal in the diet of tilapias

Abstract Numerous studies on the replacement of fishmeal with plant protein sources in tilapias have been undertaken. In order to quantify the effect of replacing fishmeal with plant protein sources on the growth performance of tilapias, a meta-analysis approach was applied. Despite the high heterogeneity and funnel plot asymmetry, the meta-analysis showed that replacing fishmeal with plant protein sources has a significant positive effect on the growth performance of tilapias. Thus, tilapias appear to be preadapted to utilizing plant protein sources. Furthermore, the feed value, nutritional quality and cost of the commonly used plant ingredients (soybean, sunflower, canola, cottonseed, kikuyu and azolla meals) were explored. The Solver function in Excel was used to formulate least-cost diets using the plant meals. Azolla had the highest nutritional index (9.7436). This was attributed to its excellent amino acid profile that exceeded the requirements of tilapias. Nutritional index and feed value were lowest in kikuyu because of its poor amino acid profile as it registered the lowest amino acid index (0.4918). These results indicate that the amino acid profile is more important in the determination of nutritional quality than the percent protein content. Azolla and soybean meal are good candidates for the replacement of fishmeal in the diets of tilapias.

Effect of Japanese sandfish (Arctoscopus japonicus) meal in paste diet for Anguilla japonica in terms of growth, feed efficiency and digestibility

In this study, the effect of replacement of high-quality fish meal (HQFM) with Japanese sandfish (Arctoscopus japonicus) meal (SFM) and the utility of a viscous culture broth of Leuconostoc mesenteroides (VCL) as binding material in paste diet for Japanese eel (Anguilla japonica) was tested in terms of growth, feed efficiency and digestibility. Four experimental paste diets contained, fish meal and binding materials as, HQFM and starch (F0, control), SFM and VCL (F1), SFM and a mixture of starch and VCL (F2) and SFM and starch (F3). Each diet was formulated to be iso-nitrogenous and iso-lipidic. Each group of 10 juvenile eels with an average initial body weight of 20 ± 2.5 g were randomly distributed into 15 tanks in triplicates and fish were fed twice daily with one of the 4 experimental paste diets for 90 days. Eels fed with diet F2 exhibited good growth performance (final mean weight; 55.3±0.67 g, WGR; 169±5%), being similar to eels (55.5±0.26g, 170±7%) fed a control diet (p&gt;0.05). In spite of iso-nitrogenous and iso-lipidic diets, the feed efficiency of F1 and F3 were inferior to other diets and the same trend was observed in growth performance also, probably due to reduced feed intake owing to poor water stability of the feeds. It should be considered that incorporation of SFM could lead to the discharge of undesirable matters such as phosphorus into the water environment, though it would contribute to lowering production costs.Therefore, further investigations are needed to improve the quality of SFM. Keywords: Fish meal replacement, Growth performance, Iso-lipidic diet, Iso- nitrogenous diet, Leuconostoc mesenteroides, Water stability.

Replacement of Dietary Fishmeal with Clostridium autoethanogenum Protein on Lipidomics and Lipid Metabolism in Muscle of Pearl Gentian Grouper.

Clostridium autoethanogenum protein (CAP) is an economical and alternative protein source. Here, three experimental diets were formulated with CAP replacing 0% (CAP-0), 30% (CAP-30), and 60% (CAP-60) of fishmeal to investigate the alterations of structure integrity, fatty acids profiles, and lipid metabolism in the muscle of pearl gentian grouper. With increasing levels of CAP substitution, the percentages of 16 : 0 or 18 : 0 were decreased in triglycerides (TG) and diacylglycerols (DG); 18 : 1 or 18 : 2 was increased at the sn-1 and sn-2 positions in phosphatidylethanolamines; 20 : 5n-3 was increased in TG and DG. The phosphatidylcholines (PC) (18 : 3/20 : 5), PC(22 : 6/17 : 1), and sphingomyelins (d19 : 0/24 : 4) were identified as potential lipid biomarkers between CAP treatments. The CAP-30 treatment enhanced lipolysis and lipogenesis, while the CAP-60 treatment inhibited lipogenesis. In conclusion, fishmeal replacement with CAP affected the lipid characteristics and lipid metabolism, whereas it did not affect the structural integrity and fatty acids profiles in the muscle of pearl gentian grouper.

Specific Blood Plasma Circulating miRs Are Associated with the Physiological Impact of Total Fish Meal Replacement with Soybean Meal in Diets for Rainbow Trout (Oncorhynchus mykiss).

High dietary SBM content is known to induce important physiological alterations, hampering its use as a major FM alternative. Rainbow trout (Oncorhynchus mykiss) juveniles were fed two experimental diets during 9 weeks: (i) a FM diet containing 12% FM; and (ii) a vegetable meal (VM) diet totally devoid of FM and based on SBM (26%). Fish fed the VM diet did not show reduced growth performance when compared with fish fed the FM diet. Nevertheless, fish fed the VM diet had an increased viscerosomatic index, lower apparent fat digestibility, higher aminopeptidase enzyme activity and number of villi fusions, and lower α-amylase enzyme activity and brush border integrity. Small RNA-Seq analysis identified six miRs (omy-miR-730a-5p, omy-miR-135c-5p, omy-miR-93a-3p, omy-miR-152-5p, omy-miR-133a-5p, and omy-miR-196a-3p) with higher expression in blood plasma from fish fed the VM diet. Bioinformatic prediction of target mRNAs identified several overrepresented biological processes known to be associated with high dietary SBM content (e.g., lipid metabolism, epithelial integrity disruption, and bile acid status). The present research work increases our understanding of how SBM dietary content has a physiological impact in farmed fish and suggests circulating miRs might be suitable, integrative, and less invasive biomarkers in fish.

Retrospect of fish meal substitution in Pacific white shrimp (Litopenaeus vannamei) feed: Alternatives, limitations and future prospects

AbstractPacific white shrimp (Litopenaeus vannamei), the most cultured crustacean in the world, has become one of the key species in the international aquatic trade accounting for 11.96% of the total aquaculture production value in 2020. The development of the aquafeed industry, especially the large‐scale use of fish meal (FM) and fish oil, contributed to promoting the expansion of shrimp production. However, the supply of FM has fluctuated at about 5 million tons per year affected by the El Nino during the last decades. This finite supply in combination with continued demand contributes to high prices, prompting the development and use of alternative protein sources. This review contributes to the development of appropriate FM replacement strategies in shrimp feed and summarises the status of research on alternative protein sources, including plant, animal and single‐cell proteins in commercial feeds for Pacific white shrimp. Furthermore, several key aspects of nutritional balances were mentioned including amino acid profiles, fatty acid nutrients and trace elements in low FM diets as well as some easily overlooked concepts that deserve attention such as epigenetics, feed processing characteristics, animal growth stages, and shrimp species improvement. Also, the prospects of future research are proposed including the application of advanced technologies (16S rRNA sequencing, transcriptomics, proteomics and metabolomics), developments in the new feed additives, along with the optimisation of new protein sources and the establishment of a precise nutritional programming for shrimp.

Dietary glutamine enhances growth performance and gut integrity of Totoaba macdonaldi juveniles fed low fishmeal diets but has limited synergetic effects in combination with a prebiotic

Fishmeal (FM) replacement using cost-effective blends of complementary ingredients is commonly used in carnivorous marine fish diets for economic and sustainable purposes. The use of functional compounds such as prebiotics or functional ingredients is a nutritional strategy in low FM diets to maximize growth and feed utilization, as well as reducing enteropathies caused by plant proteins, in particular soybean meal (SBM) that can induce enteritis in Totoaba macdonaldi juveniles. Therefore, this study was conducted to evaluate the effects of glutamine (Gln) and agavin (AGA) as a novel prebiotic or a combination of both on growth parameters, digestive capacity, whole-body proximate composition, gut health, and sustainable and economic indexes in totoaba juvenile fed low FM (17%) diet for 56 days. Juvenile totoaba with an initial weight of 168 ± 4 g were fed one of four isoproteic and isolipidic diets formulated with poultry by-product meal and FM in a 2:1 ratio and 24% of SBM. For the control basal diet (SBM), no Gln or AGA was added. The other three experimental diets consisted of the basal diet with either 1.5% glutamine (GLN), 1% prebiotic agavin (AGA), or 1.5% glutamine and 1% agavin (Gln + AGA) supplementation. Fish fed the Gln diet significantly improved growth, feed utilization and increased trypsin, total alkaline proteases, and L-aminopeptidase activities. Additionally, an enhanced brush border height (BBH) in the distal intestine was observed in the Gln group, suggesting improved intestinal health compared to the rest of the treatments. However, no significant synergistic effect was observed in fed fish the Gln + AGA diet. Interestingly, no signs of enteritis among the fish fed the four experimental diets was observed. These results suggest that fish with an initial size of 168 g are less susceptible to the adverse effects of SBM compared to previous studies. The inclusion of 1.5% dietary glutamine is recommended in totoaba diets with low FM containing 24% of SBM. Since the fish fed the diet supplemented with glutamine + agavin resulted in intermediate values for the parameters evaluated, it is recommended to evaluate different levels of agavin in combination with glutamine or perform longer bioassays using immunological or environmental challenges to aid in elucidating potential benefits of these functional compounds and their synergistic effects.

Effect of Dietary Incorporation of Yellow Mealworm as a Partial Fishmeal Replacer on Growth, Metabolism, and Intestinal Histomorphology in Juvenile Meagre (Argyrosomus regius).

Efforts have been made to find alternatives to fish meal (FM), as the sustainability of aquaculture depends on it. Insect meal (IM) is a potential candidate to partially replace FM, being more sustainable and economically viable. In this experimental trial, three diets were tested with different yellow mealworm incorporation: a control diet with no IM, a diet with an inclusion of 10% IM (Ins10), and a diet with an incorporation of 20% IM (Ins20). The diets were tested on 10.5 g meagre for 47 days. The results showed that an IM inclusion higher than 10% affected both growth (2.6 vs. 2.2) and FCR (1.5 vs. 1.9) of meagre juveniles. However, this reduction in growth did not result from lower protein retention or changes in muscle fibre area or density. Little differences were observed in the activity of pancreatic and intestinal enzymes except for aminopeptidase total activity which was higher in the control and Ins10 compared to Ins20 (3847 vs. 3540 mU/mg protein), suggesting no limitations in protein synthesis. Also, the alkaline phosphatase intestinal maturation index was higher in the control group compared to the IM groups (437 vs. 296). On the contrary, several differences were also found in the proteolytic activity in the hepatic and muscle tissues of meagre juveniles fed the Ins10 diet. The inclusion of IM had no impact on intestine histomorphology but changes were detected in the enterocytes of fish from control and Ins10 which showed hypervacuolization and nucleus misplacement compared to the Ins20 treatment. Nevertheless, a higher percentage of Vibrionaceae was recorded for meagre fed on the Ins20 diet. Since no signs of inflammation were observed in the distal intestine, this suggests IM incorporation could have had an important impact on intestinal health due to its antimicrobial properties. This is supported by an increase in the haematocrit in the treatments where IM was added (20 to 25%). In conclusion, incorporations of IM at percentages up to 10% do not seem to have a negative impact on meagre performance at this age but can enhance the fish immune system and protection against intestinal inflammation.

Influence of fish protein hydrolysate on intestinal health and microbial communities in turbot Scophthalmus maximus

This study aimed to investigate the effect of fish protein hydrolysate (FPH) on intestinal microbiota and health of turbot Scophthalmus maximus (average initial body weight 25.5 g). Two control diets were formulated to contain 360 g kg −1 (high fish meal, HFM) and 240 g kg−1 (low fish meal, LFM) of fish meal. Two experimental diets were derived from the HFM diet by replacing fish meal with FPH at levels of 100 g kg−1 (appropriate level, FPH10) or 300 g kg−1 (excessive level, FPH30). The supplementation of FPH at an appropriate level showed a positive effect on growth performance. According to chyme amino acid concentrations, moderate FPH in diets can alleviate the rate of amino acid absorption in middle intestine than excessive one (FPH30), and more thoroughly absorbed in distal intestine than fish meal (HFM) and plant protein (LFM). Histology of distal intestine showed that an appropriate level of FPH in diets could serve to alleviate the symptoms of structural damage (villi height and wall thickness) to the intestine caused by plant protein. The expressions of tight junction proteins and mucin 2 in the FPH10 and FPH30 diets was up-regulated in middle intestine compared to the LFM diet. FPH at a moderate level reduced the levels of pro-inflammatory factors (IL-1β and TNF-α) but didn't increased anti-inflammatory factors (IL-10 and TGF-β) in middle intestine compared with the LFM diet. To turbot, mucosa and chyme-associated microbiota from middle and distal intestine mainly belonged to Proteobacteria and Firmicutes. The bacterial richness, diversity and/or evenness decreased in middle intestine chyme, distal intestine mucosa and/or chyme when fish were fed diets containing FPH. Fish fed an appropriate level of FPH showed an increase of genera Bacillus in middle intestine mucosa and a decrease of genera Vibrio in distal intestine mucosa, while there was an inverse trend in fish fed an excessive level of FPH. Overall, FPH at an appropriate level showed a positive effect on intestinal health by improving middle or distal intestinal structure integrity and barrier function, as well as regulating immune-related inflammatory factors. Meanwhile, moderate FPH in diets may modulate the abundance of potentially probiotic (Bacillus) and pathogenic (Vibrio) in the intestine.

The digestive enzyme activity, intestinal microbiota and immune-related genes expression of snakehead fish (Channa argus) juveniles affected by dietary cricket (Gryllus testaceus) meal

This study aimed to investigate the potential of using cricket (Gryllus testaceus) meal as the main protein source in fish feed for snakehead fish (Channa argus) juveniles. A 10-week feeding trial was conducted to assess the effects of partial replacement of fishmeal (FM) with cricket meal (CM) on growth performance, digestive enzyme activity, intestinal microbial composition, liver antioxidant capacity, immune response and determine the appropriate replacement FM level with CM in juvenile Channa argus diet. Five isonitrogenous and iso-lipid experimental diets were formulated by replacing 0 %, 15 %, 30 %, 45 % and 60 % of FM with CM, respectively named T0 (control group), T15, T30, T45 and T60 groups. The results demonstrated T45 and T60 showed a significantly decreased feed conversion ratio (FCR) than T0 (P < 0.05). Crude lipid content was significantly higher in T45 and T60 than in T0 (P < 0.05). With increasing dietary CM content, the activities of amylase and lipase were significantly increased in T60 (P < 0.05). At the phylum level, 16S rDNA sequences revealed that Proteobacteria abundance was dominant in all treatments, while Ralstonia abundance had higher significance in T60 than others at the genus level (P < 0.05). The total antioxidant capacity (T-AOC) in liver in T30 and T45 were significantly higher than in T0 (P < 0.05). Glutathione peroxidase (GPx) activities had a significant increase in fish fed groups except T0 (P < 0.05), while malondialdehyde (MDA) content was significantly lower within T45 and T60 than T0 (P < 0.05). The up-regulated gene expression level (IL-1β, IL-10, and HSP70) and down-regulated expression level (IL-8) were showed in all treatments with CM replacement. HSP90 and Iκ-Bα expression levels were increased and peaked in T30 (P < 0.05). According to the results of the current study, in Channa argus diets, FM replacement with CM can be up to 30 % without compromising growth performance, enzyme activities, antioxidant capacity, intestinal microbiota, and immune response.

Data From Balanced replacement of fish meal with Hermetia illucens meal allows efficient hepatic nutrient metabolism and increased fillet lipid quality in gilthead sea bream (Sparus aurata)

Data From Balanced replacement of fish meal with Hermetia illucens meal allows efficient hepatic nutrient metabolism and increased fillet lipid quality in gilthead sea bream (Sparus aurata)

Kidney bean protein hydrolysate as a fish meal replacer: Effects on growth, digestive enzymes, metabolic functions, immune-antioxidant parameters and their related gene expression, intestinal and muscular gene expression

A feeding trial for 70 days was designated on Nile tilapia, Oreochromis niloticus (O. niloticus). A total of 200 fish (34.38 ± 0.05 g) were assigned into five groups, four replicates for each (10 fish/replicate; 40 fish/group) and received five isonitrogenous and isocaloric diets with five replacement levels of fishmeal (FM) with kidney bean (Phaseolus vulgaris L) protein hydrolysate (KBH) (0, 25, 50, 75, 100%). The findings demonstrated a significant increase in the performance metrics (final body weight, total weight gain, average daily weight gain, protein efficiency ratio, and specific growth rate) with a considerable improvement in the feed conversion ratio across all replacement levels, with the greatest value obtained in the KBH75 and KBH100 groups. Regarding the broken line regression analysis, the optimum FM replacement level with KBH was 76%. By replacing FM with KBH, the growth hormone and digestive enzymes (amylase and protease) levels were significantly increased, whilst the glucose and leptin hormone levels significantly declined. The amino acid transporters (solute carrier family 15 member 2 and solute carrier family 26 member 6), insulin growth factor-1, the immune-associated genes (interleukin-8, toll-like receptors-7, and cc-chemokine), and the antioxidant-associated genes (glutathione peroxidase, superoxide dismutase, and Glutathione synthetase) expression was substantially boosted in all replacement levels, where the KBH50 group recorded the highest expression. As well as the mRNA expression of myostatin was down-turned in all replacement levels relative to the KBH0 group. Improving the immune functions (lysozyme, complement 3, nitric oxide, phagocytic %, and phagocytic index) was noticed by FM replacement with KBH. The cumulative mortality as a result of challenging with Aeromonas sobria at the end of the feeding trial was decreased by increasing the replacement level (80, 40, 37, 30, and 25% for KBH0, KBH25, KBH50, KBH75, and KBH100, respectively). From the economic point of view, the feed costs and feed cost/ kg gain declined in the KBH75 and KBH100 diets. From the aforementioned outcomes, KBH could replace the FM up to 100% with improving the growth and their related genes expression, digestive enzymes activity, and immune/antioxidant parameters and their encoding gene expression, and the optimal replacement level was 76%. The replacement of FM with KBH was economically efficient.

The effects of replacing fish meal or soy protein concentrate with wheat gluten on growth, whole-body composition, and the retention and apparent digestibility coefficient of amino acids in Japanese seabass (Lateolabrax japonicus).

The aim of this study was to evaluate the effects of replacing fish meal (FM) or soy protein concentrate (SPC) with wheat gluten on growth performance, feed utilization, and nutrient digestibility and retention in Japanese seabass (Lateolabrax japonicus). Seven isonitrogenous (441-456gkg-1 crude protein) and isocaloric (21.5-22.0MJkg-1 gross energy) diets were produced to replace 0%, 33.3%, 66.7% and 100% of FM or SPC with a mixture of wheat gluten, wheat, and taurine (GWT, 77.5% wheat gluten, 20.5% wheat and 2.0% taurine). The gradual replacement of protein in FM with GWT had no significant effects on feed intake, whole-body composition, and the hepatosomatic and viscerosomatic indices, but resulted in a linear decrease in the weight gain rate, feed efficiency, and retention of nitrogen, energy, and essential amino acids (Arg, His, Ile, Leu, Lys, Met, Phe, Thr, and Val). The apparent digestibility of most essential amino acids (Cys, His, Leu, Lys, and Phe) and total amino acids increased linearly. Replacement protein in SPC with GWT had no significant effects on feed intake, growth, the feed conversion ratio, whole-body composition, and the hepatosomatic index, but resulted in a linear decrease in nitrogen, energy, and Met retention; the digestibility of Cys and Met increased linearly. Overall, wheat gluten is a more effective alternative for replacing protein in SPC than FM.

Immunoregulation and Resistance to Aquatic Pathogens with Dietary Nucleotides in Pacific White Shrimp, Litopenaeus vannamei

Using vegetable protein sources as a replacement for fish meal (FM) in the diet of Pacific white shrimp (PWS) has a negative impact on their health. Acute hepatopancreatic necrosis disease (AHPND), caused by Vibrio parahaemolyticus, affects PWS and causes financial losses. Nucleotides modulate the immune response and could contribute to counteracting these issues. Our objective was to evaluate the effects of nucleotide supplementation on performance, immune response, and survival when challenged with V. parahaemolyticus, in PWS receiving a diet with FM partially replaced with vegetable protein sources. A feeding trial (1000 PWS; 56 days) and a challenge trial (600 PWS; 10 days) were performed using diets with different FM inclusion levels (26%, 23.4%, 22.1%, and 20.8%), with or without 0.1% nucleotides. A non-challenged, non-supplemented group was also used in the challenge trial. Adding nucleotides to diets with reduced FM allowed significantly better results in growth performance parameters and total hemocyte count (THC). In the challenge trial, compared to control, nucleotide supplementation led to significantly higher THC and survival rate 15 h post-challenge. In conclusion, adding nucleotides to PWS diets improves their immune response and resistance to aquatic pathogens, allowing FM to be replaced by vegetable protein sources without negatively affecting performance.