Growth Performance Of Fish Research Articles

Effects of saline and alkaline stresses on the survival, growth, and physiological responses in juvenile mandarin fish (Siniperca chuatsi)

Saline-alkaline water is widely distributed and abundant worldwide. It plays a critical role in the advancement of the aquaculture and the comprehensive utilization of saline-alkaline resources. The mandarin fish (Siniperca chuatsi), a freshwater species with high economic value, and has potential for cultivation in such environments. We evaluated its tolerance to acute salinity and alkalinity, and investigated the growth and physiological changes under chronic saline and alkaline stress. Initially, the effects of acute salinity and alkalinity were estimated on mandarin fish (4.33 ± 0.31 g), and found that the LC50 for 96 h of salinity and alkalinity was 13.91 ppt and 13.45 mmol/L, respectively. Subsequently, over a 60-day period, we measured the survival, growth performance, and physiological responses in mandarin fish (22.53 ± 0.60 g) reared in freshwater (FW, the control group), saline water (SW; fixed salinity of 5 ppt) and alkaline water (AW; carbonate alkalinity of 8 mmol/L). The results indicated that neither SW nor AW group adversely affected survival rates, and growth performance in SW group was significantly superior to the FW group. Additionally, compared to the FW group， the AW group had a lower hepatosomatic index, while the SW group exhibited significantly higher meat content. In terms of physiological responses, the AW group showed elevated V-H+-ATPase (VHA) activity, whereas the SW group had decreased prolactin (PRL) levels. Furthermore, the mitochondria-rich cells (MRCs) in mandarin fish underwent morphological adaptations to saline and alkaline stress, indicating their role in osmoregulation and acid-base balance. Our results suggested that the mandarin fish demonstrated good tolerance to both salinity and alkalinity, indicating suitability for breeding in low saline and alkaline water. This research contributes to a broader understanding of saline and alkaline tolerance in aquaculture species and provides theoretical support for the cultivation of mandarin fish in saline-alkaline water. Moreover, the results of this study suggested that saline-alkaline areas and agricultural irrigation water in the world could be successfully utilized for sustainable aquaculture.

Enhancing Indoor Culture of Weather Loach (Misgurnus anguillicaudatus) and Caipira Lettuce (Lactuca sativa) in a Decoupled FLOCponics System

Interest in aquaponics (AP) is increasing due to its ability to minimize sewage and maximize feed efficiency in fish farming. However, owing to limitations of intensive cultures and a lack of nutrients such as NO3 for growing crops, AP requires the use of artificial nutrients. Therefore, novel approaches are required to develop AP-intensive culturing methods. An AP system based on biofloc technology (BFT) called FLOCponics (FP) has been recommended. Here, the productivity of the weather loach (Misgurnus anguillicaudatus) in the FP system, BFT system, and flow-through systems (FTSs), as well as these systems’ effect on Caipira lettuce (Lactuca sativa) growth, was analyzed. To compare crop productivity, a hydroponic (HP) bed was installed. The growth rate of M. anguillicaudatus showed significant differences, at 51.1 ± 3.69% in the FP system, followed by 24.0 ± 4.16% in the BFT system and −14.3 ± 1.4% in the FTS. Its survival rates were better in the FP system (91.1 ± 2.64%) than in the BFT system (82.1 ± 10.98%) or the FTS (66.8 ± 2.75%) (p < 0.05). Total ammonia nitrogen and NO2−-N concentrations were stabilized in every plot during the experimental period. However, the NO3−-N concentration continuously increased in the BFT system but decreased in the FP system and was maintained. The shoot weight of the Caipira lettuce was 163.6 ± 8.65 g in the FP system and 149.6 ± 9.05 g in the HP system. In conclusion, FP system can provide a large amount of nutrients and improve the growth performance of both fish and crops in the FP system.

Nano-selenium (nano-Se) removes the detrimental impacts of plant-based diets on the production performance and well-being of common carp (Cyprinus carpio)

Fishmeal (FM) is not a sustainable source of nutrients due to the over-exploitation of fisheries resources and increasing aquafeed costs. Plant protein (PP) sources have been utilized as FM alternatives in diets. A 60-day nutritional experiment was conducted to study the effects of the complete replacement of FM with PP ingredients in diets supplemented with nano-Se on growth performance, plasma physiological and immunological parameters, and liver antioxidant capacity of common carp (Cyprinus carpio). Five experimental diets were prepared, where FM-Control contained 35 % FM, PP-Control contained complete PP ingredients, and NSe1, NSe2, and Nse3 contained complete PP ingredients supplemented with 1, 2, and 3 mg/kg nano-Se, respectively. The growth performance of fish fed the FM-Control and NSe3 diets was higher than in the PP-Control group (P < 0.05). The best feed conversion and protein efficiency ratios were detected in the NSe3 group but were not significantly different from the FM-Control group (P > 0.05). While the highest levels of antioxidant parameters, including reduced glutathione, superoxide dismutase, catalase, and glutathione peroxidase, were detected in the liver of fish fed with the FM-Control diet, the lowest malondialdehyde concentration was measured in the NSe3 group (P < 0.05). Plasma levels of lysozyme activity, alternative complement activity, and total immunoglobulin of the FM-Control and NSe3 groups were significantly higher than in other groups (P < 0.05). The best plasma physiological parameters including the lowest levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, cholesterol, triglycerides, and low-density lipoprotein, and the highest levels of total protein, triiodothyronine (T3), and high-density lipoprotein were observed in fish fed with the FM-Control and NSe3 diets (P < 0.05). These results suggest that FM can be entirely substituted by PP in diets containing nano-Se at 3 mg/kg without harmful impacts on the performance and immunity of common carp.

Maximization of brackish water productivity for the sustainable production of striped catfish (Pangasianodon hypophthalmus) and grain sorghum (Sorghum bicolor (L.) Moench) cultivated under an integrated aquaculture–agriculture system

Freshwater scarcity, salinity, and poor soil fertility are the major challenges affecting both food and feed productions in arid and semi-arid regions of the world. Utilization of brackish water in the production of saline-tolerant fish and valuable field crops under an integrated system is promising in the maximization of yield per crop. The aim of this study, therefore, was to (1) assess the effect of saline aquaculture wastewater on the growth, yield, forage quality, and nutritive composition of sorghum seeds and (2) assess the effect of different water qualities on the survival, growth performance, and health status of Pangasianodon hypophthalmus. The experiment was conducted in a randomized completely block design of four salinity treatments with three replicates, i.e., control (freshwater mixed with inorganic fertilizers), 5000 ppm, 10,000 ppm, and 15,000 ppm. Our results indicated that although the control exhibited the highest growth (plant height, leaf number, internode number, leaf area, and soil–plant analysis development), grain, and forage yield, no significant differences were noted among the treatments. Likewise, no significant difference in the grain nutrient composition was noted among all the treatments. Assessment of the forage quality revealed improved crude protein content in the control compared to the saline treatments. However, no significant differences in the leaves and stalks fiber fractions were noted among all the treatments. Furthermore, rumen fermentation in terms of in vitro digestibility indicated no significant differences in the in vitro digestible dry matter, digestible organic matter, metabolic energy, net energy, microbial protein, short-chain fatty acids, and total dissolved nutrients among the treatments. However, rearing P. hypophthalmus in water salinities exceeding 10,000 ppm reduced the growth performance and health status of fish. Therefore, the integration of sorghum and P. hypophthalmus production in water salinities not exceeding 5000 ppm is a viable alternative to maximize brackish water productivity in freshwater-scarce regions.

Nitrogenous compounds, fish and plant growth were impacted by hydraulic loading rates on the aquaponic bed with açai seed (Euterpe oleracea)

The study investigated the hydraulic loading rate (HLR) for an aquaponic bed with açai seed in a hybrid system with tambaqui (Colossoma macropomum). 240 juveniles tambaqui with an initial average weight and length of 21.8 ± 7.74 g and 11.28 ± 6.88 cm were distributed in 12 independent aquaponics systems. HLRs were calculated and four different rates of 1.4, 5.4, 13.6 and 23.3 m3 day−1 m−2 were established, all in triplicate and applied for eight weeks. Water quality, as well as fish growth performance, germination and growth of açai seeds were evaluated. HLRs modified dissolved oxygen, pH, alkalinity, conductivity, total dissolved solids, ammonia, nitrite, and nitrate between treatments. Ammonia removals (mg h−1) were 2.6 times higher in HLR of 23.3 and 13.6 m3 day−1 m−2. Phytotechnical performance of açai seedlings (germination) and fish growth performance were significantly reduced at HLR 1.4 m3 day– 1 m−2. The final weights of the tambaqui were significantly higher (116.3 ± 5.77 g) at HLR 5.4 m3 day−1 m−2. Given the results observed, the HLR for improved system performance was 13.6 m3 day−1 m−2, considering the experimental model presented in the present study.

Application of Herbal Medicine in Aquaculture Sector for the Control of Fish Disease and Growth Performance: A Review

Aquaculture is a fast-growing animal food-producing industry in India. With the growing human population, dependence on aquaculture to provide a proteinaceous and economical supply of food has increased. The use of antibiotics is becoming increasingly widespread in the aquaculture industry to provide a protein-rich food supply, which is having negative impacts on human populations. As the benefits of medicinal herbs become clear, the use of antibiotics can be reduced gradually. Various medicinal herbs are known to have excellent some properties, such as antiviral, antibacterial and antifungal activity, enhancing fish growth, etc. The purpose of this paper is to provide the latest scientific information on the application of medicinal herbs in aquaculture sectors as well as to review the potential problems and recommendations for the application of medicinal herbs in aquaculture.

Integrative analysis of metagenome and metabolome provides new insights into intestinal health protection in Coilia nasus larvae via probiotic intervention

With the development of large-scale intensive feeding, growth performance and animal welfare have attracted more and more attention. Exogenous probiotics can promote the growth performance of fish through improving intestinal microbiota; however, it remains unclear whether intestinal microbiota influence physiological biomarkers. Therefore, we performed metagenomic and metabolomic analysis to investigate the effects of a 90-day Lactiplantibacillus plantarum supplementation to a basal diet (1.0 × 108 CFU/g) on the growth performance, intestinal microbiota and their metabolites, and physiological biomarkers in Coilia nasus larvae. The results showed that the probiotic supplementation could significantly increase weight and body length. Moreover, it could also enhance digestive enzymes and tight junctions, and inhibit oxidative stress and inflammation. The metagenomic analysis showed that L. plantarum supplementation could significantly decrease the relative abundance of Proteobacteria and increase the relative abundance of Firmicutes. Additionally, pathogenic bacteria (Aeromonadaceae, Aeromonas, and Enterobacterales) were inhibited and beneficial bacteria (Bacillales) were promoted. The metabolome analysis showed that acetic acid and propanoic acid were significantly elevated, and were associated with Kitasatospora, Seonamhaeicola, and Thauera. A correlation analysis demonstrated that the digestive enzymes, tight junction, oxidative stress, and inflammation effects were significantly associated with the increased acetic acid and propanoic acid levels. These results indicated that L. plantarum supplementation could improve intestinal microbial community structure and function, which could raise acetic acid and propanoic acid levels to protect intestinal health and improve growth performance in C. nasus larvae.

Feasibility of molasses-fermented banana peel as a protein source in practical diet for hybrid tilapia (Oreochromis spp.): effect on growth and feed efficiency

This study aims to increase the utilization of banana peels, a local agricultural by-product, by improving nutrient value and partially reducing the presence of anti-nutritional factors (ANFs) as an alternative ingredient in fish feed. The feasibility of molasses-fermented banana peels (MFBP) as a protein source in a practical diet for hybrid tilapia (Oreochromis spp.) fries was investigated. Five isonitrogenous experimental diets containing 0 (control), 25, 50, 75, and 100% substitution levels of fish meal by MFBP were formulated. Twenty tilapia fries per group with three replicates were fed for eight weeks. The growth performance and feed efficiency values of fish were recorded and evaluated. Fish fed with 0, 25, and 50% MFBP levels showed significantly higher growth parameters, survival rate, and feed utilization efficiency than those fed with 75 and 100% MFBP levels. Although the control diet produced better growth performance and feed utilization efficiency than MFBP-based diets there was no significant difference between fish fed with the control diet and the low MFBP levels (0-50%) diet. Based on the present findings, it could be concluded that the molasses-fermented banana peels (MFBP) could efficiently replace the fishmeal by up to 50% without affecting the growth performance of red tilapia.

Dual Role Of Streptomyces Strains: Reduction of Aeromonas Counts In Both Culture Water And The Intestine, And Growth Enhancement of Discus Fish (Symphysodon sp.)

Discus fish (Symphysodon sp.) brings the largest export turnover to the ornamental fish industry in Vietnam. The intensive farming of discus fish to meet export market demand leads to a higher risk of bacterial disease, with Aeromonas being the main infectious agent. Continuous antibiotic use exerts selective pressure, fostering the emergence of antibiotic-resistant bacterial strains capable of causing diseases in fish. Streptomyces sp. considered as probiotics with the role of replacing antibiotics in applications such as promoting growth, improving survival rates, and controlling pathogenic bacteria in aquaculture. The primary objective of this study was to assess the influence of Streptomyces sp. on the growth performance, and Aeromonas density in intestine of discus fish and in culture water. Discus fish fed diets containing Streptomyces sp. TM1, TM7, and TM22 showed significantly higher growth parameters (45.24 - 58.72% of final body weight - FBW, 14.8 - 16.66% of final body length -FBL, 16.03 – 20.87 % of specific growth rate of weight – SGRW, 10.79 - 12.05 % of specific growth rate of length – SGRL, and 41.48 – 46.54 % of feed conversion ratio – FCR) compared to the control. Additionally, total Aeromonas densities of the fish treated with TM1, TM7, and TM22 showed a notable decrease compared to the control treatment in the rearing water with log CFU/ml values of 4.517 (Control), 2.554 (TM1), 2.571 (TM7), 2.222 (TM22) and in the intestines of fish with log CFU/g values of 5.597 (Control), 3.828 (TM1), 3.806 (TM7), 3.648 (TM22). Streptomyces sp. TM1, TM7, and TM22 could decreased total Aeromonas count in the gut of discus fish and in the rearing water, and boost the growth performance of discus fish (Symphysodon sp.).

Comparative Study of Growth Performance of Three Tilapia Strain in Intensive Culture System

High stocking density is an important factor in cultivation to increase the eficency if fish farming for nutrition requirements. High stocking density generally impact on fish physiology and growth performance. However, many studies on individual fish have different growth perfromance from different strain. Some technology had been developed to optimize tilapia production in high stocking density. This study aimed to determine the growth performance of three different strain of tilapia (red tilapia, nirwana tilapia, and jatimbulan tilapia) reared in 20 m3 of round tarpaulin with additional of microbubble generator. This study used an intensive system with 100 fish/m3 of stocking density. The results showed that the microbubble generator was able to increase the carrying capacity of water quality such as increasing dissolved oxygen in the waters, temperature and pH. The high content of dissolved oxygen in the water significantly increasing the growth of tilapia. The highest weight was found in red tilapia with a final weight of 199.56 ± 0.05 gr, followed by Nirwana tilapia with 176.59 ± 0.10 gr, and Jatimbulan tilapia with 153.91 ± 0.06 gr. In addition, the high content of dissolved oxygen in the waters also affect the rearing period of tilapia.

Fish Growth Performance in RAS Pond Using Hydrocyclone Mechanical Filter

The high feeding and the metabolic output of the fish in intensive aquaculture can cause various problem, such as poor water quality and slowing down the fish growth performance. Recirculating Aquaculture System (RAS) is a solution to maintain water quality. Unfortunately, the conventional mechanical filter in RAS such as japmat is inefficient. One strategy that can be applied is to use a hydrocyclone. This research aims to observe the fish growth performance in RAS pond using hydrocyclone mechanical filter and its comparison with the use of japmat. Research method was performed by comparing hydrocyclone and japmat in the pond with the RAS system. The research design is completely randomized design (CRD), with three replications in each treatment. The research was carried out through five stages, namely hydrocyclone set-up, RAS ponds set-up, water quality analysis, fish growth measurement, and statistical analysis. Based on the Independent Samples Test, the use of hydrocyclone mechanical filters has a significant effect (P&lt;0.05) on the measured water quality parameters (DO, Temperature, pH, TDS, NH3) except for NO2. Hydrocyclone significantly affect Average Daily Growth and Specific Daily Growth parameters. Whilst, the Survival Rate and Feed Conversion Ratio parameters, it did not give significant effect

Effects of Psidium guajava and Phyllanthus amarus extracts on digestive enzyme activity and growth of Pangasianodon hypophthalmus fingerlings under high-temperature stress

The rise in water temperature by global warming is of high concern to aquaculturists. In this study, the effects of extracts-based diets on digestive enzymes, and growth performance in Pangasianodon hypophthalmus fingerlings under elevated temperatures were investigated. Four distinct diets (control, Psidium guajava, (0.2%/kg) – Pg0.2, Phyllanthus amarus (0.5%/kg) – Pa0.5, and a mixture of Pg0.2 and Pa0.5 - Mix.) were administered to fish fingerlings for 42 days, followed by 4 days of temperature elevation. Fish were then continuously subjected for 42 days to temperatures of 27, 31, and 35°C to evaluate enzymatic activities and growth performance of fish. The results showed that although there is no interaction between two experimental factors on digestive enzyme activity and growth performance of fish, Pg0.2 followed by Mix groups accelerated digestive enzymes (trypsin, chymotrypsin, amylases and pepsin). Besides, enzymatic activities increased from 31°C to 35°C. The highest growth was observed from fish at 35°C followed by those at 31°C (p&lt;0.05) which was significantly higher than the control (27°C); however, there was no significant difference in survival rate. In conclusion, these findings suggested 2 appropriate diets (Pg0.2 and Mix) for optimizing growth of this species and consequently contributing to the sustainable aquaculture under the global warming scenario.

Effects of exercise training on the external morphology, growth performance, swimming ability, body composition and metabolism of juvenile black seabream Acanthopagrus schlegelii

Multiple studies have shown that exposure to moderate water currents (exercise training) can improve growth and physiological performance of hatchery-reared fish. Proactive implementation of sustained aerobic swimming training can be particularly beneficial for improving post-release performance of fish in stock enhancement- or ‘ranching’ programs. Black seabream Acanthopagrus schlegelii is an important species in aquaculture and stock enhancement in the East China Sea. For juveniles of this species, we assess the impacts of exercise training at various flow rates on the morphology, growth performance, swimming ability, body composition and locomotors metabolism. A group of sibling juvenile fish (initial mass: 13.72 ± 0.29 g) underwent daily exercise training for 12 h (9:00–21:00) over 30 days at four different water velocities (0, 1, 2, or 4 body lengths per second, BL/s). All the trained fish exhibited a significant decrease in their respiratory metabolic rate during the test of swimming ability. Fish from the 2 BL/s training group exhibited a significantly increased burst swimming speed compared to the other groups. Fish from 1 BL/s training group showed elevated hexokinase activities in the white muscle and citrate synthase activities in the liver compared to the 0 BL/s group. Citrate synthase activities in the white muscle of fish from the 2 BL/s training group were elevated, along with citrate synthase activities in the liver, as compared to 0 BL/s. The fish in the 4 BL/s training group showed a tendency for increased crude protein content and a corresponding decrease in crude lipid content. Morphological analysis revealed that fish in the 4 BL/s group exhibited larger dorsal fins and more streamlined body profiles, compared to 0 BL/s. Activities of white muscle citrate synthase as well as liver hexokinase activity were higher in the 4 BL/s group, while lactate content activity in the white muscle were lower compared to 0 BL/s. These findings underscore the effectiveness of training at 2 BL/s, offering a promising strategy to enhance the performance of juvenile black seabream for stocking initiatives.

Marine Fish Oil Replacement with Lard or Basa Fish (Pangasius bocourti) Offal Oil in the Diet of Tiger Puffer (Takifugu rubripes): Effects on Growth Performance, Body Composition, and Flesh Quality.

Lard (LD) and Basa fish offal oil (BFO) have similar fatty acid profiles, both containing high contents of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). The present study aimed to investigate the efficacy of partial or complete replacement of marine fish oil (MFO, herring oil) by LD or BFO in the diets of tiger puffer. The control diet contained 49.1% crude protein and 9.28% crude lipid content including 6% added MFO. In other diets, 1/3, 2/3, and 3/3 of the added MFO was replaced by LD or BFO, respectively. Each diet was fed to triplicate tanks of juvenile fish (initial body weight, 13.88 g). A 46-day feeding trial was conducted in a flow-through seawater system. Each diet was fed to triplicate 200-L rectangular polyethylene tanks, each of which was stocked with 30 fish. Fish were fed to satiation three times a day. The complete replacement of added MFO (replacing 65% of the total crude lipid) had no adverse effects on fish growth performance in terms of survival (>94%), weight gain (360-398%), feed intake (2.37-3.04%), feed conversion ratio (0.84-1.02), and somatic indices. The dietary LD or BFO supplementation also had marginal effects on fish body proximate composition, biochemical parameters, muscle texture, and water-holding ability, as well as the hepatic expression of lipid metabolism-related genes. Partial (2/3) replacement of added MFO by LD or BFO did not significantly reduce the muscle n-3 LC-PUFA content, indicating the n-3 LC-PUFA sparing effects of SFA and MUFA in LD and BFO. In general, dietary LD or BFO reduced the peroxidation level and led to significant changes in the muscle volatile flavor compound profile, which were probably attributed to the change in fatty acid composition. The results of this study evidenced that LD and BFO are good potential lipid sources for tiger puffer feeds.

Water Quality and Growth Performance of Nile Tilapia (Oreochromis niloticus), Chia (Salvia hispanica) and Lemon Grass (Cymbopogon citratus) in a Media-based Aquaponics System

High ammonia levels in enclosed fish production systems negatively impact fish growth and hinder optimum production. The objective of this study was to evaluate the (i) biofiltration potential of chia (Salvia hispanica) and lemon grass (Cymbopogon citratus) (ii) the influence of the plant filters on water quality and fish growth in an aquaponic system. Treatments included a control-without plants, S. hispanica, and C. citratus aquaponic systems. The study was conducted for 3 months in Aqualife fish farm, Machakos, Kenya. Water quality parameters, growth performance of fish and plants were monitored during the experiment. The plant treatments significantly (P&lt; 0.05) reduced ammonia levels compared to the control (0.07 ± 0.17 mgL-1). There was a remarkable 32-fold decrease in ammonia compared to the hydroponic inlet. Planted aquaponic systems significantly (P &lt; 0.05) reduced nitrite and nitrate concentrations compared to the control, indicating effective nutrient cycling and improved water quality. Notably, both S. hispanica (115. 5 ± 3.2 g) and C. citratus (130.3 ± 3.32 g) systems significantly (P &lt; 0.05) boosted the growth performance of O. niloticus compared to the control (113. 5 ± 3.2 g). C. citratus performed better (450 ± 9.17 g) than S. hispanica (217.6 ± 2.52 g). These findings highlight the potential of the plants as sustainable and efficient biofilters, enhancing overall aquaponic system performance and contributing to a more productive and environmentally friendly approach to food production.

Bioaccumulation Influences of some heavy metals on growth performance of Solea solea fish in Lake Qaroun, Egypt

Bioaccumulation Influences of some heavy metals on growth performance of Solea solea fish in Lake Qaroun, Egypt

Comparative evaluation of raw and fermented Eichhornia crassipes leaf meal in the diet of Cyprinus carpio fingerlings: Effects on growth performance, body composition and haemato-biochemical responses

Eichhornia crassipes leaf meal (ELM) was fermented by solid-state fermentation using Chaetomium globosum MTCC 4179 that resulted in considerable changes in its nutrients and anti-nutrient profile. Both fermented ELM (FELM) and raw ELM were evaluated in the feed of Cyprinus carpio fingerlings through a feeding trial of 56 days. Five iso-nitrogenous and iso-caloric diets viz. C, Control (30% DORB and 0% ELM or FELM), ELM15 (15% ELM with replacement of 50% DORB), ELM30 (30% ELM with replacement of 100% DORB), FELM15 (15% FELM with replacement of 50% DORB), and FELM30 (30% FELM with replacement of 100% DORB) were prepared and fed on satiation basis to 180 acclimated fish (body weight 8.38–8.48 g) of five respective groups in triplicate with the stocking density of 12 fish /tank. Significantly (P<0.05) higher weight gain (%), specific growth rate, and protein efficiency ratio and lower feed conversion ratio (FCR) were observed in ELM15 and FELM15 groups compared to the control. However, the growth performance of ELM30 and FELM30 groups showed no significant (P>0.05) difference with control group. Furthermore, fermented diets (FELM15 and FELM30) could not improve the growth performance of fish as compared to their non-fermented counterparts (ELM15 and ELM30). Total red blood cell count, packed cell volume (%), and total serum protein (g/dl) were significantly (P<0.05) higher in ELM15 compared to other ELM and FELM-based groups. Better body composition was observed in fish of ELM15 group, however, fish of control, and ELM30 showed similar body protein, lipid, ash and total carbohydrate. Thus, it is concluded that raw ELM can be incorporated in the diet of common carp up to the level of 30% with complete replacement of DORB without compromising the growth performance of fish. However, the fermentation of ELM with Chaetomium could not impart any additional benefits in terms of growth performance of fish. In addition, dietary inclusion of 15% raw or fermented ELM, in replacement of 50% DORB, can result in higher growth performance with better health condition of common carp fingerlings.

Identification of SNPs and candidate genes associate with growth performance in all-female mandarin fish (Siniperca chuatsi) by a genome-wide association study

The all-female mandarin fish (Dinggui I, Siniperca Chuatsi) was recently approved by Ministry of Agriculture and Rural Affairs of the People's Republic of China as a new strain of mandarin fish (GS-04-001-2021). Select breeding of fast-growing lines is an important goal of the mandarin fish industry. However, single nucleotide polymorphisms (SNPs) associated with growth of Dinggui I mandarin fish remains unclear. Therefore, a genome-wide association study (GWAS) was performed on 5 growth traits (body weight, body length, whole length, body height and body thickness) of 192 mandarin fish. A total of 49,940 SNPs were identified by ddRAD-seq. Among them, a total of 6 significant SNPs were detected on multiple chromosomes. The proportion of phenotypic variance explained for these SNPs ranged from 9.66% to 19.47% for growth traits. Specifically, 4 SNPs were associated with all traits. Several candidate genes (AKT2, CCNT2, EPB41L2 and CAMKMT) were identified based on these SNPs. The loci were verified in 100 individuals, indicating the reliability of candidate SNPs. Our results contribute to understanding of growth traits and the development of molecular marker-assisted selection in all-female mandarin fish.

Can the genetic background modulate the effects of feed additives? Answers from gut microbiome and transcriptome interactions in farmed gilthead sea bream (Sparus aurata) fed with a mix of phytogenics, organic acids or probiotics

The synergies between selective breeding and feed additives remain under-explored in farmed fish, despite their sustainability. Reference (REF) and selected gilthead sea bream for growth (GS) were fed with the control (CTRL) diet during 14 days. CTRL diet was oil-coated with three functional additives (PHY: phytogenic based on garlic and medium chain fatty acid; OA: organic acid mixture with a 70% of butyric acid sodium salt; PROB: probiotic based on Bacillus subtilis, pumillus and licheniformes species). These experimental diets were then sequentially administered at high (PHY/OA = 7.5 g/kg, PROB = 2 × 1011 CFU/kg; 2 weeks) and low (PHY = 5 g/kg, OA = 3 g/kg, PROB = 4 × 1010 CFU/kg; 10 weeks) additive doses. The capacity of a given genotype and additive to modify the fish growth performance, gut health and the host interaction with its anterior intestine (AI) microbiota was evaluated as a whole population or individually (9 fish/diet/genetics). GS fish showed a better growth and feed conversion ratio, linked to a reduced individual variability of gut microbial composition. The PHY additive had a major impact upon the intestinal transcriptome of GS-PHY fish, with the up-regulation of markers of epithelial integrity, sphingolipid and cholesterol/bile salt metabolism. With the OA additive, impaired growth performance, reduced AI goblet cell area and enhanced AI granulocyte infiltration were concomitant with a down-regulation of neutrophil degranulation markers associated with a decrease of pathogenic genera (Staphylococcus/Streptococcus/Neisseria), and an over-representation of acetone/butanol/ethanol fermentation and vitamin K biosynthesis inferred pathways. Bacillus establishment and lack of AI inflammation were parallel in PROB fish of both genetic backgrounds. However, GS fish grew and utilized feed better with the additive, whereas a worsening appeared in REF fish. This amelioration was related with a higher abundance of the nitrate-reducer Kocuria, an up-regulation of markers of epithelial cell maintenance and proliferation, and a down-regulation of microbiota-correlated protein synthesis and ubiquitination markers, supporting a reduced epithelial turnover and improved intestinal barrier function. Overall, the success of nutritional innovations in gilthead sea bream is largely dependent on the host genome predisposition, but also on the intestinal microbiota according to the hologenome theory.

Effects of Dietary Inclusion of a Crude Protein Source Exhibiting the Strongest Attractiveness to Red Sea Bream (Pagrus major) on Growth, Feed Availability, and Economic Efficiency.

Dietary incorporation of an attractive feed protein source is a practical method of enhancing feed intake and consequently improving the growth of fish. The attractiveness of 18 crude protein sources to juvenile red sea bream (Pagrus major) and the effects of the dietary inclusion of the crude protein source that exhibited the strongest attractiveness on growth, feed availability, and economic efficiency were determined. Jack mackerel meal (JMM) showed the strongest attractiveness to red sea bream among 18 crude protein ingredients. In an 8-week feeding trial, 810 juveniles were randomly distributed into 27 tanks (30 fish/tank). Nine experimental diets were prepared. The control (Con) diet included 60% fish meal (FM). Various levels (1, 3, 5, 10, 20, 40, 60, and 100%) of JMM were included at the expense of FM in the Con diet, and the resulting diets were named the JMM1, JMM3, JMM5, JMM10, JMM20, JMM40, JMM60, and JMM100 diets, respectively. Fish were hand-fed to apparent satiation twice daily for 8 weeks. The weight gain, specific growth rate, and feed consumption of red sea bream that were fed the JMM40, JMM60, and JMM100 diets were significantly (p < 0.0001 for all) higher than those of the fish fed all other diets. However, dietary JMM inclusion had no remarkable impacts on the feed utilization, biological indices, and chemical composition of the whole body of red sea bream. In terms of the economic view of the study, the economic profit index of red sea bream fed the JMM40, JMM60, and JMM100 diets was significantly (p < 0.0001) greater than that of the fish fed all other diets. In conclusion, the strongest attractiveness to red sea bream among 18 crude protein sources was observed in JMM. The inclusion of more than 40% JMM at the expense of FM in the diet of red sea bream is highly recommended for practical feed formulations to induce remarkable improvement in the growth performance of fish and the economic returns for farmers.