Fish Meal Diet Research Articles

Fish Meal Replacement by Chicken By-Product Meal in Diet: Impacts on Growth and Feed Availability of Juvenile Rockfish (Sebastes schlegeli), and Economical Analysis.

A 56-day feeding experiment was carried out to evaluate the effects of substituting fish meal (FM) with chicken by-product meal (CBM) in diets on the growth and feed utilization of rockfish (Sebastes schlegeli). Six experimental diets were formulated to be isonitrogenous and isolipidic. The control (Con) diet included 55% FM. In the Con diet, 10%, 20%, 30%, 40%, and 50% of FM was replaced with CBM, named as the CBM10, CBM20, CBM30, CBM40, and CBM50 diets, respectively. A total of 540 juvenile fish were distributed into 18 tanks (30 fish per tank and 3 tanks per diet) and fed to apparent satiation two times daily for 56 days. The weight gain and specific growth rate of rockfish fed the CBM10 and CBM20 diets were comparable to rockfish fed the Con diet. The feed consumption of rockfish fed the Con and CBM10 diets was significantly (p < 0.001) higher than that of fish fed all other diets, except for the CBM20 diet. However, protein retention, biometric indices, chemical composition, amino acid profiles, and plasma and serum parameters of rockfish were not significantly influenced by dietary FM substitution with CBM. The Con, CBM10, and CBM20 diets showed superior (p < 0.001) economic profit index (EPI) compared to the CBM30, CBM40, and CBM50 diets. Conclusively, FM up to 20% could be substituted by CBM in diets without impairing growth, feed availability, chemical composition, amino acid profiles, and blood parameters of rockfish grown from 2.5 g to 12.5 g. However, the long-term effects of CBM substitution or the potential use of combined CBM and other alternative protein sources for FM in rockfish diets are needed in future.

Selection of Nonlethal Early Biomarkers to Predict Gilthead Seabream (Sparus aurata) Growth.

One of the main challenges in aquaculture is the constant search for sustainable alternative feed ingredients that can successfully replace fishmeal (FM) without any negative effects on fish growth and health. The goal of the present study was to develop a toolbox for rapidly anticipating the dynamics of fish growth following the introduction of a new feed; nonlethal, biochemical, and molecular markers that provide insights into physiological changes in the fish. A nutritional challenge by feeding a conventional feed rich in FM protein (FM diet) versus an experimental feed rich in plant protein (PP) and low FM inclusion (PP diet), in 20 different families of gilthead sea bream (Sparus aurata) was performed. Fifteen and 30 days after the initiation of the nutritional challenge, the transcriptional response of gilthead seabream erythrocytes along with classical hematological biochemical markers were compared. Zootechnical, biochemical, and transcriptome data from each family under different dietary treatments were combined into a classification model to identify variables that can predict the growth rate at the end of the 14-month farming period (July 2018-September 2019). A highly accurate model was produced (A > 80%) based on the combination of seven markers (five molecular and two biochemical markers) and with high potential in separating faster and slower growing fish as early as 30 days after the initiation of feeding.

The Use of Black Soldier Fly Larvae Meal H. illucens for the Pre Growth of Oreochromis niloticus (Linnaeus, 1758) Fingerlings Reared in Floating Cages in Benin

To increase the value of black soldier fly (Hermetia illucens) larvae in the diet of Tilapia reared on aquaculture farms in Benin, three diets RR, RT and R55 were tested in triplicate in floating cages for 35 days on Oreochromis niloticus fingerlings with a mean initial weight Pmi = 7±0.220 g. The stocking density was 70 fingerlings/m3. RR is an imported commercial feed while RT is a fishmeal diet. R55 is a diet based on Black Soldier Fly Larvae (BSFL) meal with an incorporation rate of 55%. Control fishing was carried out every 7 days and hematological constants were determined. The results show that the feed tested significantly affect zootechnical parameters (p ˂ 0.05). The Final Mean weight (FMW) of fingerlings fed the experimental diets ranged from 16.37±1.18 (RT) to 21.53±1.42 (R55). The best specific growth and economic conversion rates were obtained with R55 (3.21±0.064 %day-1 and 0.95±0.18%), which also had better Hb levels. An incorporation rate of 55% of BSFL meal in the feed of O. niloticus fingerlings therefore induced good zootechnical performance and better economic profitability.

GROWTH AND SURVIVAL OF SPINY LOBSTER, Panulirus homarus JUVENILES FED WITH DIFFERENT FORMULATED FEEDS

Article Highlights- Indonesia has remarkable natural resources of spiny lobster Panulirus homarus and an exceptional opportunity to establish the largest lobster aquaculture industry in the world.- However, culturing lobsters still relies on natural feeds (trash fish of fresh fishery by-catch) which are inefficient and environmentally unsustainable.- Developing formulated feed based on locally available ingredients is invaluable for replacing natural feeds to support sustainable lobster culture.- Formulated feed made of local fish meal provided the best growth of juvenile spiny lobster Panulirus homarus compared to imported fish meal. AbstractSeveral studies suggested that good growth performance and survival of lobster juveniles can be achieved by feeding the lobsters with formulated feeds. This study aimed to (1) evaluate the growth and survival of spiny lobster Panulirus homarus juveniles fed with different diets having profiles based on a basal diet formulation and (2) to compare the growth of lobsters fed with an identical formulated feed with variations only in sources of fish meal and dry matter content. The feeding experiment was designed following a completely randomized design (CRD) with five diet treatments and five replicates for each treatment. Five experimental diets were prepared in this experiment, i.e., Diet A (basal diet prepared as moist pellets); Diet B (moist pellets with the same formulation as Diet A, using local fish meal); Diet C (moist pellets with the same formulation as Diet A, using imported fish meal); Diet D (dry pellets with the same formulation as Diet A, using imported fish meal); and Diet E (fresh fish). Juveniles of spiny lobster with an average weight of 3.00±0.07 g were allocated in 25 net cages (60 x 60 x 60 cm) placed in a circular HDPE canvas tank (7.5 m in diameter) at a density of 15 lobsters/cage in a flow-through seawater system. The juveniles were fed with the experimental diets twice/day for 12 weeks. The experiment showed that the best growth was observed in juveniles fed with moist feed containing local fish meal (Diet B) with the final weight reaching 18.74±2.30 g. Moist feed containing imported fish meal (Diet C) resulted in a higher survival rate (46.66%), and the lowest survival rate (13.33%) was obtained from juveniles fed with fresh fish (Diet E).

Supplemental effects of Haematococcus pluvialis in a low-fish meal diet for Litopenaeus vannamei at varying temperatures: growth performance, innate immunity and gut bacterial community

This study examined the effects of Haematococcus pluvialis on the growth performance, innate immunity, and gut microbiota of Litopenaeus vannamei under different water temperature conditions. Feeding regimens included a 20% fishmeal diet (control), a low-fish meal (LFM) diet with 10% fishmeal and an LFM diet supplemented with 0.03% H. pluvialis. These diets were administered to six groups of L. vannamei at normal (30°C) (NT) and low (20°C) (LT) temperatures (NT_C, NT_LFM, NT_LFM_HP, LT_C, LT_LFM, and LT_LFM_HP) over 8 weeks. The weight gain rate of L. vannamei in group NT_LFM_HP was significantly higher compared to group NT_LFM. Astaxanthin levels and body pigmentation intensity in L. vannamei were significantly increased in the NT_LFM_HP and LT_LFM_HP groups. Moreover, hepatopancreatic antioxidant capacities, such as superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC), were lower in normal-temperature groups compared to the low-temperature groups. Nevertheless, antioxidant capacity was significantly higher in both the NT_LFM_HP and LT_LFM_HP groups compared to the control group. Meanwhile, the expression levels of antioxidants were significantly higher at lower temperatures compared to higher temperatures, with the NT_LFM_HP and LT_LFM_HP groups exhibiting the highest expression levels. Additionally, the mRNA levels of genes associated with the Toll and IMD pathways indicated immunoregulatory effects in the organism. The expression levels of immune genes were significantly higher at lower temperatures, especially in the NT_LFM_HP and LT_LFM_HP groups compared to the control groups. Notably, significant differences in gut microbial composition were observed in the NT_LFM_HP group compared to other groups, with variations influenced by temperature and fishmeal content. Specifically, Vibrionaceae abundance was significantly lower in the LT_LFM_HP group compared to the control group. The results also revealed that the abundance of Actinomarinales was significantly higher in low-temperature groups, with the LT_LFM_HP group displaying the greatest increase. Overall, these findings suggest that L. vannamei may be susceptible to reduced fishmeal levels, potentially impacting growth and immune function. Furthermore, H. pluvialis supplementation may assist L. vannamei in acclimating to prolonged low-temperature conditions.

Fishmeal intervention after short-term novel proteins stimulates compensatory growth and affects intestinal health in largemouth bass (Micropterus salmoides).

This research utilized a compensatory growth phenomenon aimed at reducing the use of fishmeal in aquatic animal feed. However, the compensatory growth triggered by fishmeal restriction with novel protein replacement has yet to be understood. Five isonitrogenous and isolipidic diets containing different proteins were manufactured, with fishmeal serving as the control and diets containing novel proteins, i.e., Chlorella (Chlorella vulgaris), cottonseed protein concentrate, Clostridium autoethanogenum, and yellow mealworm (Tenebrio molitor), serving as the experimental diets. Largemouth bass (Micropterus salmoides) with a starting body weight of 4.73 ± 0.04g were respectively fed these five diets for the first 29days (first stage), followed by a fishmeal diet for the remaining 29days (second stage). The diet of fishmeal, Chlorella vulgaris, cottonseed protein concentrate, Clostridium autoethanogenum, and Tenebrio molitor was referred to as FM, ChM, CSM, CAP, and TM, respectively. All novel protein groups showed a 60-73% higher weight gain compared to the fishmeal group during the second phase; however, they did not reach the weight level seen in the control group. In addition, the second stage of fishmeal intervention resulted in a reduction of approximately 35% in the area of positive Alcian blue (AB) staining of intestinal tissues in the CSM group, and about 40% in the CAP group, compared to the first stage. Furthermore, the area of intestinal apoptosis in TM was enlarged after fishmeal intervention while it was decreased in other experimental groups. At day 58, gene expression analysis of the CAP group fish at the end of the trial revealed increased levels of the anti-apoptotic gene bcl-2, as well as higher expression of intestinal inflammatory cytokines il-1β, tnf-α, nf-κb p65, and il-10, compared to the FM group. In terms of the biochemical indices, the levels of catalase (CAT) and glutathione peroxidase (GSH-Px) were reduced in CSM on day 58. An assessment of potential microbial function at end of trial demonstrated that CAP could reduce the lipid metabolism and amino acid metabolism, and increased carbohydrate metabolism pathways in the largemouth bass intestine. In conclusion, both CAP and ChM groups showed promise to reduce fishmeal with respect to intestinal health rather than growth. This study should be of value to practitioners wishing to use novel proteins to reduce fishmeal via the utilization of the compensatory growth phenomenon.

Quantitative Genetics of Feed-Efficiency-Related Traits for the Pacific Whiteleg Shrimp Penaeus vannamei in a Plant-Based Diet Environment.

Selecting shrimp strains that perform well on a plant-based diet holds promise for solving the fishmeal (FM) shortage issue, with genetic improvement of feed efficiency (FE) being a key focus. This study compared a plant-based (fishmeal-free) diet with a 25% FM diet for the Pacific whiteleg shrimp (Penaeus vannamei) to determine whether the FE-related traits, including residual feed intake (RFI), average daily weight gain (ADG), and daily feed intake (DFI), exhibit diet-specific genetic variations and genotype-by-diet (genotype × diet) interactions. Results showed that RFI was significantly higher under the plant-based diet treatment compared to the FM-based diet treatment (0.0049 g/d vs. -0.0045 g/d, p < 0.001), while ADG was notably lower (0.043 g/d vs. 0.110 g/d, p < 0.001), indicating that a plant-based diet may lead to reduced yields and impact the profitability of shrimp culture. In the case of being unable to estimate common environmental effects, the heritability estimates of RFI under the plant-based and FM-based diets were 0.743 ± 0.157 and 0.440 ± 0.125, respectively, and those of ADG and DFI ranged from 0.314 ± 0.121 to 0.947 ± 0.158. Genetic correlations between diets for RFI and DFI were 0.646 ± 0.162 and 0.549 ± 0.163, respectively, suggesting a degree of genotype × diet interactions. In contrast, the genetic correlation between diets for ADG was only 0.296 ± 0.259, indicating a strong genotype × diet interaction. These findings highlight the importance of considering selective breeding for improved feed efficiency in a plant-based diet environment.

Liver Structure and Function in Yellowtail Kingfish, Seriola lalandi, in Response to Reduced Fish Meal Diets

ABSTRACTAlterations to lipid storage, and the consequent effects on liver structure, need to be considered when replacing wild‐derived fish meal (wd‐FM) with alternative ingredients in formulated diets for commercially aquacultured species. The replacement of wd‐FM is likely to alter the available level of precursors for bile acid production, potentially impacting the absorption of dietary lipids and fat‐soluble vitamins. In this 252‐day study, Yellowtail Kingfish, Seriola lalandi (2.52 ± 0.25 kg; 546 ± 20 mm [fork length; mean ± standard deviation]) were fed five different diets. A 30% wd‐FM diet served as a control. Dietary wd‐FM inclusions were reduced to 20% and 10%, replaced with FM by‐product meal. In addition, dietary wd‐FM levels were reduced to 20% and replaced with poultry meal (PM) or soy protein concentrate (SPC) in two other separate diets. Fat deposition in the liver was similar amongst all treatment groups with bile duct proliferation and periductular fibrosis observed in the livers of fish fed diets with wd‐FM replacement with 10% PM or 10% SPC. Fish fed FM by‐product meal at 10% and 20% replacement displayed similar liver structures to control fish. Yellowtail Kingfish fed a 30% wd‐FM diet may have the FM replaced by up to 66.67% FM by‐product, 33.3% PM or 33.3% SPC without any significant impact on total bile acid synthesis, storage and excretion and liver lipid storage. This research expands our ability to deliver cost‐effective nutritional solutions in support of Yellowtail Kingfish culture.

Supplementation of Yupingfeng polysaccharides in low fishmeal diets enhances intestinal health through influencing the intestinal barrier, immunity, and microflora in Macrobrachium rosenbergii.

This study aimed to investigate the effects of a low-fishmeal diet (LF, substituting soybean meal for 40% fish meal) and the supplementation of 500 mg/kg and 1000 mg/kg Yu Ping Feng (YPF) polysaccharides on the growth performance, antioxidant enzyme activities, intestinal ultrastructure, non-specific immunity, and microbiota of Macrobrachium rosenbergii. The study involved the administration of different diets to M. rosenbergii, including a control diet, a low-fishmeal diet (LF), and LF diets supplemented with 500 mg/kg and 1000 mg/kg YPF polysaccharides. Growth performance, antioxidant enzyme activities, intestinal ultrastructure, non-specific immunity, and microbiota were assessed. The LF diet significantly reduced growth performance parameters compared to the control group. However, YPF supplementation notably improved these parameters, with the greatest improvement observed at a 1000 mg/kg dosage. Antioxidant enzyme activities (SOD, GSH-PX) were diminished in the LF group, accompanied by elevated MDA levels, whereas YPF supplementation restored these activities and reduced MDA levels. Ultrastructural analysis revealed that the LF diet caused intestinal villi detachment and peritrophic matrix (PM) shedding, which were alleviated by YPF. Gene expression related to PM formation (GS, CHS, EcPT) was downregulated in the LF group but significantly upregulated in the 1000P group. Non-specific immune gene expressions (IMD, Relish, IκBα) and enzyme activities (NO, iNOS) were suppressed in the LF group but enhanced by YPF supplementation. Microbial community analysis showed reduced diversity and altered composition in the LF group, with increased Proteobacteria and decreased Firmicutes, which were partially restored by YPF. Correlation analysis revealed that Lactobacillus and Chitinibacter play pivotal roles in regulating intestinal health. Lactobacillus exhibited a positive relationship with the intestinal PM and immune-related indicators, whereas Chitinibacter was negatively associated with these factors. These results highlight the adverse impacts of a low-fishmeal diet on the intestinal health of M. rosenbergii and demonstrate the beneficial effects of YPF polysaccharides in alleviating these negative consequences through various mechanisms, including improved growth performance, enhanced antioxidant enzyme activities, restored intestinal ultrastructure, and modulated immune responses. The findings suggest that YPF supplementation could be a valuable strategy for mitigating the negative effects of low-fishmeal diets in aaquaculture.

Effect of Poultry By-product Meal as Replacement for Fish Meal in Diets of Gilthead Seabream (Sparus aurata) Juveniles

This study investigated the effects of replacement of fish meal (FM) with poultry by-product meal (PBM) at 55%, 65% and 75% on growth performance and amino acid metabolism of juvenile gilthead seabream (Sparus aurata) with an initial weight of 35.01±0.11 g for 120 days. The study also evaluated protein and amino acid digestibility to determine their influence on protein metabolism in juvenile seabream. The results indicated that partial replacement of FM with PBM in diets of juvenile gilthead seabream is feasible up to 65% without compromising their growth performance, feed consumption and digestibility (P&gt;0.05). Additionally, hepatosomatic (HSI) showed no significant differences between all groups (P&gt;0.05). The viscerosomatic index (VSI) level was at the highest value, whereas the condition factor (K) was at the lowest value in CTRL (P&lt;0.05). The highest feed conversion ratio (FCR) value was in the 75PBM group (P&lt;0.05). However, there was no statistically significant difference between CTRL and the other PBM groups (P&gt;0.05). Similarly, feed intake and whole-body protein content did not significantly differ among dietary groups (P&gt;0.05). The protein efficiency ratio (PER) values suggest that replacing FM with PBM (up to 65%) in diets of juvenile gilthead seabream is effective and produces diets with high-quality proteins and digestibility coefficients comparable to those of the control group (P&gt;0.05). Additionally, amino acid profiles of juvenile gilthead seabream fed with diets containing up to 75% PBM showed no deficiencies in essential amino acids. Nevertheless, we can suggest that 75% PBM substitution for FM can be used in the diets of gilthead seabream, although it causes a slight decrease in growth, FCR and protein digestibility. These results suggest that partial replacement of FM with PBM can be a viable strategy for feeding juvenile gilthead seabream, offering a sustainable advantageous alternative.

Effects of hydrolyzed hairtail protein partially replacing fish meal in diets on growth and protein turnover rate for hybrid grouper (Epinephelus fuscoguttatus♀×E. lanceolatus♂)

The high protein content and digestibility of hydrolyzed hairtail protein (HHP) promise a superior protein source for aquatic animal diets. In this experiment, the feasibility of HHP as an alternative for fishmeal (FM) in diets of hybrid grouper (Epinephelus fuscoguttatus♀×E. lanceolatus♂) was evaluated by exploring its impact on growth and protein turnover rate. For this, three iso-nitrogenous and iso-energetic extruded diets were formulated: one with FM (33 %, HHP0); two with 10 % (HHP1) and 20 % (HHP2) FM protein replaced by HHP. After a 60-day feeding trial, an independent effect of dietary HHP levels on grouper growth performance, body composition, and nutrient retention efficiency was recorded. However, a second-order increase in the hepatosomatic index (HSI) and dry matter apparent digestibility coefficient (ADC) was plotted with increasing dietary HHP levels. Furthermore, results showed no adverse effect on protein turnover rate in muscle tissue at different dietary HHP levels, while the relative contribution ratio (RCR) from HHP on growth was lower than that from the equal amount of FM. Overall, our finding indicated that up to 20 % FM protein could be replaced by HHP without adverse effects on growth, body composition, nutrient retention efficiency, digestibility coefficient, and protein turnover rate.

Assessment of the nutritional impact of substituting fishmeal with enzymatically hydrolyzed jojoba meal (Simmondsia chinensis) in the diets of Nile tilapia, Oreochromis niloticus

Enzymatic hydrolysis is a technology that is widely used to enhance the biological and functional characteristics of plant proteins and deactivate anti-nutritious components. In order to tackle this pressing issue, considerable research has been conducted on plant-based proteins as a potential substitute. This study sought to comprehensively examine the impacts of replacing fish meal with enzymatically hydrolyzed jojoba meal (EHJM) in the Nile tilapia, Oreochromis niloticus diets. After the enzymatic hydrolysis process for jojoba meal, hydrolyzed amino acid content increased in enzymatically hydrolyzed jojoba meal (EHJM), while fiber content, phytic acid, saponins, and trypsin inhibitors dramatically decreased. A thorough evaluation of key parameters included growth, gene expression, digestive enzyme activity, digestibility, intestinal histomorphometry, biochemical indicators, and antioxidant enzyme activity. Fish (n = 360, 6.41 ± 0.05 g fish−1) were allocated at random to four groups consisting of four replacement levels of fishmeal protein content with EHJM: 0 % (control diet), 25 % (EHJM25), 50 % (EHJM50) and 75 % (EHJM75) for 74 days. The results showed both the control diet and the EHJM25 groups showed remarkable improvements in performance metrics such as final body weight, specific growth rate, weight gain, feed conversion ratio, and protein efficiency ratio, with no discernible variations between them. The inclusion of EHJM up to 50 % produced a noteworthy (P < 0.05) rise in the intestinal lipase and amylase activities. Furthermore, a high apparent digestibility coefficient for crude lipid and protein values was observed in EHJM25% and EHJM50%. The presence of EHJM up to 25 % in tilapia diets, as a substitute for FM, had a significant impact (P < 0.05) on various parameters in the intestine, including goblet cells, muscularis mucosa, villi height, villi width, absorption area, and height muscularis. Moreover, the inclusion of EHJM with different levels in tilapia diets resulted in a noticeable reduction (P < 0.05) in alkaline phosphatase (ALP) and serum alanine aminotransferase (ALT) levels, with fish given the EHJM75% diet showing the lowest amounts in their plasma. In addition, the amount of plasma total protein, albumin, and globulin were found to rise sharply with the escalating replacement of EHJM in fish diet, reaching the highest values in the EHJM25% and EHJM50% diets. Interestingly, the catalase (CAT) and superoxide dismutase (SOD) levels in fish that were given the control diet and EHJM25% showed a remarkable increase compared to the other treatments (P < 0.05). Fish fed EHJM50% diet had the highest glutathione peroxidase and the lowest malondialdehyde levels. In addition, the fish that were fed the control diet exhibited the highest expression of insulin-like growth factor and growth hormone genes, compared to those fed the EHJM25% diet. Based on the results, the EHJM25% and EHJM50% diets were more effective than the EHJM75% diet in improving the efficiency of Nile tilapia. The inclusion of EHJM in Nile tilapia diets had a neutral effect on growth indices compared to a fishmeal diet (control diet). The optimal replacement level is 55.3 %.

Positive effects of Lithospermum erythrorhizon extract added to high soybean meal diet on growth, intestinal antioxidant capacity, intestinal microbiota, and metabolism of pearl gentian grouper

This study aims to investigate the effects of adding 2 ‰ Lithospermum erythrorhizon (LE) extract to the high soybean meal diet on the growth, intestinal antioxidant capacity, intestinal microbes, and metabolism of pearl gentian grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). Three diets included FM, SBM, and SBMLE, in which FM was the whole fish meal diet, SBM was the soybean meal replacing 50 % fish meal protein, and SBMLE was the SBM diet supplemented with 2 ‰ LE extract. After a 56-day feeding trial, the results showed the weight gain rate (WGR), specific growth rate (SGR), and feed efficiency rate (FER) of pearl gentian grouper in FM and SBMLE group was significantly higher than that of SBM (P < 0.05). Furthermore, high soybean meal dietary added LE extract inclusion significantly increased the SOD, CAT, and GSH-Px activity while significantly decreasing the MDA level (P < 0.05). Significant differences were in the gene expression of cytokines il1-β, il8, tnf-α, il10, and tgf-β between the SBMLE and SBM groups (P < 0.05). In addition, Microbiomics results revealed increased ASVs and alterations in gut microbiota composition, characterized by a decrease in Bacteroidota and an increase in Proteobacteria, Nautella, and lactococcus after adding LE extract. Furthermore, the substantial reduction in Firmicutes and Acidobacterota induced by high soybean meal feed was reversed by LE extract. Metabolic pathway enrichment analysis showed that LE extract mitigated soybean-induced enteritis (SBMIE) by affecting two critical metabolic pathways: arachidonic acid metabolism and histidine metabolism. In conclusion, adding LE extract to a high soybean meal diet can improve the growth performance and immunity of the pearl gentian grouper, and LE can play a mitigating role in SBMIE by regulating lipid metabolism, amino acid metabolism, and intestinal flora balance.

Artemisinin supplementation improves growth, lipid metabolism, and intestinal microbiota of golden pompano (Trachinotus ovatus) fed high cottonseed meal diets

This study aimed to investigate the effect of artemisinin supplementation to high cottonseed meal (CSM) diet on the growth, lipid metabolism and intestinal microbiota of golden pompano (Trachinotus ovatus). Five diets were formulated, including the control (CM, with CSM replacing 16 % of fishmeal) and experimental groups (CA0, CA2, CA4, and CA8, with CSM replacing 36 % of fishmeal and supplemented with 0 %, 0.20 %, 0.40 %, and 0.80 % of artemisinin, respectively). 375 fishes (initial weight 22.45 ± 0.07 g) were randomized into five groups of triplicates each and fed in tanks for 8 weeks. Results indicated that 0.8 % artemisinin improved final weight, weight gain rate and specific growth rate, reduced the serum lipid levels under the condition of 36 % fishmeal replaced with CSM. In the liver, artemisinin supplementation alleviated hepatocyte vacuolization and lipid deposition induced by the high level CSM replacement fishmeal diet, reduced the activity of lipogenesis-related enzymes and increased lipolysis-related enzyme activity. In the intestine, supplementation with 0.8 % artemisinin significantly increased the activities of intestinal digestive enzymes. Supplementation with 0.8 % artemisinin significantly increased the diversity and stability of the intestinal microbiota of the golden pompano, while also reducing the abundance of potentially harmful Vibrio associated with high CSM levels. In conclusion, 0.8 % artemisinin supplementation mitigated the negative effects of high CSM diets on growth, lipid metabolism, and liver health in golden pompano by enhancing lipid metabolism, intestinal digestive enzyme activity, and modulating intestinal microbiota.

Interaction of dietary replacements of fishmeal by protein blend and feeding frequency on growth performance and protein utilization of gibel carp (Carassius gibelio var. CAS Ⅴ)

Feeding frequency represents a potential strategy to improve the utilization of protein sources by fish. This study investigated its impact on the utilization of protein blend in gibel carp. The dietary fishmeal was totally substituted with three protein blends consisting of Tenebrio molitor meal, Chlorella meal, Clostridium autoethanogenum protein, cottonseed protein concentrate, at ratios of 1:1:8:2, 1:1:6:4, and 1:1:4:6, respectively. During an 8-week feeding trial, a total of 960 healthy fish (18.10 g) were randomly assigned to eight groups, each with three replicates. Then they were fed either twice daily (two meals per day) or four times daily (four meals per day) with four different diets. Higher feeding frequency increased feed intake and intestinal trypsin activity (P < 0.05), and up-regulated the expression levels of genes related to amino acid or peptide transporter (pept1, y+lat2) and sensory receptors (casr, gprc6a, mglur4) in intestine (P < 0.05). Moreover, it accelerated muscle protein turnover by increasing free amino acid content, aspartate aminotransferase activity and akt1 transcript levels (P < 0.05), ultimately promoting growth. However, higher feeding frequency reduced protein apparent digestibility and feed efficiency (P < 0.05). Dietary blended proteins elevated trypsin and chymotrypsin activities (P < 0.01). Notably, the adverse effects observed with blended proteins (ratio at 1:1:8:2) on total essential amino acid digestibility and muscle protein metabolism-related gene expression were mitigated with increased feeding frequency, thus alleviating growth inhibition. Furthermore, the blended proteins at a ratio of 1:1:6:4 increased protein apparent digestibility (P < 0.05), down-regulated mstn expression level (P < 0.05), and up-regulated expression levels of genes related to protein synthesis (akt1, mtor, s6k1, eif4b, eif4e; P < 0.05); thereby promoting protein utilization and muscle growth at four meals per day. Overall, feeding frequency interacted synergistically with blended proteins to influence growth and protein utilization in gibel carp, and a protein blend with a ratio of 1:1:6:4 was a superior alternative to fishmeal at both feeding frequencies. Future strategies aimed at replacing dietary fishmeal should consider the role of feeding frequency as a critical factor.

Bovine bone meal combined with dephenolized cottonseed protein is an effective fishmeal substitution in Trachinotus ovatus feed: A comprehensive evaluation of growth, muscle quality, and intestinal digestion physiology

To investigate the feasibility of substituting fishmeal (FM) with a combination of bovine bone meal (BBM) and dephenolized cottonseed protein (DCSP), a mixture (consisting of 60 % BBM and 40 % DCSP) was used to replace varying FM levels in Golden pompano (Trachinotus ovatus) feed. Five isoproteic (47 %) and isolipidic (12 %) experimental diets were formulated, with FM levels set at 30 %, 24 %, 18 %, 12 %, and 6 % (namely Control, FM24, FM18, FM12, and FM6). To compensate for the reduced FM content, BBM and DCSP were used as substitutes, and DL-methionine and L-lysine were added to maintain the dietary amino acid balance. Following a 63-day trial, results showed that the growth of FM24, FM18 and FM12 groups did not exhibit significant differences compared to the Control group, while those of FM6 group considerably decreased. The biochemical composition of whole fish did not display significant differences among the five groups, while the muscle protein contents of the FM12 group were higher than the Control group. Most of the muscle texture properties were positively modified in the FM 12 and FM 6 groups. With the substitution ratio increase, the contents of serum total protein, albumin, total amino acids, and cholecystokinin were elevated, while serum peptide YY contents decreased. In addition, intestinal trypsin, NaK-ATPase, and alkaline phosphatase activities in FM18, FM12, and FM6 groups decreased, and lipase activities exhibited the opposite trend. The transcription levels of genes related to amino acid-sensing receptors (asct2 and snat2) were down-regulated with increasing dietary FM substitutions, while the expression levels of appetite regulation factors (pept1, cck, and ghrl) were up-regulated. In conclusion, the FM content in the diet of T. ovatus can be reduced to 12 % through the utilization of a combination of BBM and DCSP, with no adverse effects observed on growth performance, biochemical composition, or muscle texture.

Effects of dietary fish meal replacement by Periplaneta americana meal on growth, metabolism, intestinal health and resistance against Aeromonas hydrophila of Micropterus salmoides

An 8-week culture experiment was conducted to investigate the effects of partial replacement of fish meal (FM) with Periplaneta americana meal (PAM) on growth performance, body composition, serum biochemical parameters, intestinal health and resistance against Aeromonas hydrophila of largemouth bass, Micropterus salmoides. A total of 450 healthy largemouth bass with an initial body weight (IBW) of 14.55±0.09 g were randomly divided into five groups. Five experimental diets were prepared by replacing 0 % (P0), 15 % (P15), 30 % (P30), 45 % (P45) and 60 % (P60) of the FM in the basal diet with PAM, respectively. The results showed that final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) were no significant difference in P15 and P30 compared with the control group (P > 0.05). Crude protein of whole fish body was significantly increased and crude lipid was significantly decreased in all PAM groups (P < 0.05). In the P30, the antioxidant enzyme activities were significantly higher than those in the control and other experimental groups, and malondialdehyde (MDA) was significantly decreased (P < 0.05). The activities of α-amylase and pepsin increased significantly in P15 and P30 and decreased significantly in P45 and P60 (P < 0.05). Lipase was significantly increased in all groups except P15 than in the control group (P < 0.05). There were no significant differences in villus height (VH), crypt depth (CD), and muscle thickness (MT) among all groups (P > 0.05), but villus width (VW) was significantly decreased in P45 and P60 (P < 0.05). The relative expression of IL-10 and TGF-β1 were first up-regulated and then down-regulated, while IL-8 was opposite (P < 0.05). The relative expression of Casp3, Casp9 and IFN-γ were significantly up-regulated in P45 and P60 (P < 0.05). After injecting A. hydrophila, all groups of largemouth bass experienced mortality, but cumulative mortality was lowest in the P30. In conclusion, PAM can partially replace FM in the diet of juvenile largemouth bass. The replacement of no more than 30 % is unlikely to adversely affect growth performance, and can increase the crude protein content of the whole fish body, and is beneficial to intestinal health.

Thraustochytrids and Algae as Sustainable Sources of Long-Chain Omega-3 Fatty Acids for Aquafeeds

There is limited ability to biosynthesize long-chain omega-3 fatty acids such as EPA and DHA in food webs leading to humans. Seafood is the key source of ω3 LC-PUFA, with aquaculture expected to meet rising global demand; however, marine fish have a high dietary requirement for EPA and DHA themselves. This was traditionally met using unsustainable dietary fish oil and fish meal, but limited supply and environmental concerns have dictated research on replacements. Among the industrial sources of EPA and DHA, microalgae and especially thraustochytrids stand out as resources with high concentrations. Although unicellular, thraustochytrids are not microalgae as they are not photosynthetic but instead are microheterotrophs. This removes the light requirement and facilitates high yields of monoculture for the production of single-cell oils. The availability, in high concentrations, of usually one or the other essential fatty acid permits a calibration of the EPA and DHA dose, which is especially useful as their effects have mainly been considered together in medical and aquaculture research. EPA and DHA have different effects on cell function and are precursors of different bioactive compounds. Using thraustochytrids, microalgae, and heterotrophic dinoflagellates, the importance of DHA has been investigated. DHA was essential for optimizing the growth of the early life stages of scallops and finfish and was preferentially incorporated into fish membrane phospholipids. The production of microalgae and microheterotrophs can contribute to the treatment of wastewater and waste gas, further enhancing their sustainability and reducing the environmental costs of aquaculture.

Replacement of fish meal with defatted black soldier fly (Hermetia illucens) in diet of Pacific white shrimp (Litopenaeus vannamei): growth, flesh quality and transcriptome

Abstract This study evaluated the impacts of replacing fish meal (FM) with defatted black soldier fly (Hermetia illucens; BSF) on the growth performance, flesh quality and transcriptome of Pacific white shrimp (Litopenaeus vannamei). In a diet containing 560 g/kg FM, BSF was used to replace 0%, 20%, 40%, 60%, 80% and 100% of dietary FM (BSF0, BSF20, BSF40, BSF60, BSF80 and BSF100). Thus, six isonitrogenous and isolipidic diets were prepared, and then fed to juvenile Pacific white shrimp (1.70 ± 0.10 g) for 60 days. In growth performance, the BSF20 group showed the similar FCR and WGR to the control group (), and the other four BSF groups presented significantly lower WGR and higher FCR than the BSF0 group (). The flesh chewiness and the contents of crude lipid, collagen and total amino acid in flesh were significantly decreased (), and flesh cooking loss, thawing loss was significantly increased when the replaced FM was ≥40% (). When the replaced FM reached 60%, the flesh hardness, heat-insoluble collagen content, shear force, body surface redness and the ratio of n-3/n-6 fatty acids were significantly lower (), while n-6 polyunsaturated fatty acid content and total free amino acid content in flesh were significantly higher than those of the BSF0 group (). Hepopancreatic samples were used for transcriptomic analysis, and a total of 1,456 differentially expressed genes (DEGs) were identified between the BSF groups and BSF0 group, which were mainly involved in growth-promoting, energy metabolism and antioxidant capacity key pathways and genes, including the cathepsin L, folate synthesis pathway, redox-related genes and glutathione metabolism pathway. In conclusion, in a diet containing 560 g/kg FM, BSF could successfully replace 20% of dietary FM, and higher FM replacement (≥40%) decreased the growth performance and flesh quality of Pacific white shrimp.

Impact of dietary lysine on growth, nutrient utilization, and intestinal health in triploid rainbow trout (Oncorhynchus mykiss) fed low fish meal diets

Lysine is one of the essential amino acids for fish growth and development. This study investigated the effect of dietary lysine on growth performance, digestion, and intestinal health of triploid rainbow trout (Oncorhynchus mykiss) (initial body weight: 9.00 ± 0.33 g) fed a low fish meal diet (15 %). Five dietary lysine levels (3.66 %, 3.84 %, 4.19 %, 4.32 %, and 4.55 %) were evaluated for 56 days, with three replicates of 30 fish per level. The results showed that the weight gain rate (198.55 %), specific growth rate (1.95), and VSI were maximized when the dietary lysine level was 4.19 %. The 4.19 % lysine group exhibited minimum moisture (66.66 %) and maximum crude protein (15.47 %), with no significant differences in crude lipid and ash contents. Growth factors mTOR and 4EBP-1, on the other hand, had the highest expression in the 4.19 % group, while IGF-1 and S6K1 peaked in the 4.32 % group. The anti-inflammatory factors TGF-β, NF-κB, IL-4, and IL-10 peaked at different levels and then decreased with increasing lysine levels. The pro-inflammatory factor IL-1β, on the other hand, had the lowest expression at the 4.19 % level. Based on quadratic regression analysis of specific growth rate, the lysine requirement of triploid O. mykiss in low fish meal diets was 4.24 %.