Specific Growth Rate Of Fish Research Articles

Effects of dietary tocotrienol on growth, digestive enzyme activities, antioxidant capacity, histology, and disease resistance of Largemouth Bass fingerlings

AbstractObjectiveWe sought to assess the efficacy of feeding tocotrienol, a member of the vitamin E family, as it impacts physiological functions in fingerling fish.MethodsFingerling Largemouth Bass Micropterus nigricans with an initial mean body weight (±SD) of 0.98 ± 0.09 g were fed five diets containing tocotrienol at 0, 10, 20, 30, and 40 mg/kg (T0, T10, T20, T30, and T40 diets, respectively) for 42 days. After the feeding experiment, fish were challenged with Largemouth Bass ranavirus (LMBV) and monitored for 48 h.ResultFindings indicated a positive impact of tocotrienol‐supplemented diets on fingerling survival. Furthermore, the weight gain and specific growth rate of fish that received the T30 and T40 diets were significantly higher than those of fish that were fed the T0 diet. Tocotrienol supplementation improved the protein efficiency ratio and condition factor and increased the whole‐body lipid and protein content. Conversely, the hepatosomatic index, viscerosomatic index, and feed conversion ratio were significantly decreased by tocotrienol supplementation. Fish that were fed the T30 and T40 diets exhibited significantly higher hepatopancreas lipase activity and intestinal protease activity. Generally, superoxide dismutase and catalase activities in the liver increased as the tocotrienol level increased. Additionally, the liver malondialdehyde concentration decreased, and there was an improvement in the structure of liver cell tissue. Survival at 48 h after the LMBV challenge was significantly higher in fish that were fed the T30 and T40 diets compared to fish that were given the T0 diet. Maximum specific growth rate was observed at a tocotrienol concentration of 33.63 mg/kg.ConclusionResults suggest that supplementation of Largemouth Bass fingerling diets with appropriate quantities of tocotrienol can enhance survival, growth, antioxidant capacity, digestion, and uptake of nutrients as well as disease resistance.

Effect of Dietary Lysine and DL-Methionine Supplementation in Roasted Soyabean-Based Diet on the Growth Performance and Blood Profiles of Clarias gariepinus

This study was designed to investigating the growth performance, hematology, and serum biochemistry of Clarias gariepinus nourished with roasted soyabean based diets with varied inclusion of dietary amino acid. A total of 360 Clarias gariepinus juveniles, aged eight weeks and weighing 19.0±0.4 grams, were randomly assigned to six different diets with varying inclusion levels of lysine and DL-methionine (g/100g). The diets were as follows: RS1 (Control) without lysine or DL-methionine supplementation; RS 2 - 0g + 1g; RS 3 - 0.25g + 0.75g; RS 4 - 0.5g + 0.5g; RS 5 - 0.75g + 0.25g; and RS 6 - 1g + 0g of Lysine and DL-methionine. For 84 days, the fish were fed until they were completely satisfied. Each treatment was in triplicate. Supplementing lysine and methionine in a diet based on roasted soybeans did not significantly (P>0.05) effect on the growth parameter such as final weight, feed conversion ratio, and/or specific growth rate in fish. A significantly higher survival rate was observed in fish on diet RS 5 (85.60±0.60) and was closely followed by fish fed diet RS 3 and RS 4. Fish fed diets RS 4 and RS 5 exhibited significantly higher (P<0.05) packed cell volume (PCV %) and hemoglobin levels. While, White blood cell counts (x10^9/L) varied significantly among the different diets. The addition of supplemental amino acids did not significantly (P>0.05) affect total protein (g/L), and the values ranges from 6.60±0.52 (RS 6) to 7.87±0.55 (RS 4). This study showed that supplementation of lysine and DL-methionine in Roasted Soyabean based diet could improve growth performance of fish with no adverse effect on fish health.

Evaluation of Gamma Aminobutyric Acid and Sodium Butyrate in Juvenile Red Seabream (Pagrus major) Diets Containing Graded Levels of Fish Meal and Soy Protein Concentrate.

The experiment was conducted to evaluate the supplementary effects of gamma aminobutyric acid (GABA) and sodium butyrate (SB) when a graded level of fish meal (FM) was replaced with soy protein concentrate (SPC) in diets for juvenile red seabream (Pagrus major). A control diet was designed to contain 60% FM (F60). Two other diets were formulated by reducing FM levels to 40% and 20% with SPC (F40 and F20). Six more diets were formulated by adding 0.02% GABA or 0.2% SB to each F60, F40 and F20 diets (F60G, F60S, F40G, F40S, F20G and F20S). Each diet was randomly assigned to a triplicate group of fish (5.52 g/fish) and provided for eight weeks. Final body weight, weight gain and specific growth rate of fish fed F60G, F60S, F40G and F40S diets were comparable and significantly higher (p < 0.05) than other groups. The growth of fish fed SB-containing diets was significantly increased (p < 0.05) compared to fish fed the respective control diets. The feed efficiency and protein efficiency ratios were significantly higher (p < 0.05) in the fish fed all diets containing 60% and 40% FM compared to F20 and F20G groups. The F40S diet resulted in the highest feed utilization values. The F20S group exhibited significantly higher (p < 0.05) feed utilization than the F20 and F20G groups. Serum lysozyme activity was significantly higher (p < 0.05) in fish fed the GABA- and SB-containing diets compared to the F20 group. The F60S group exhibited the highest lysozyme activity which was significantly higher (p < 0.05) than in the F20 and F40 groups. Therefore, the growth performance, feed utilization and innate immunity of red seabream can be enhanced by dietary supplementation with GABA or SB in low-FM diets containing SPC. The FM level in the juvenile red seabream diet can be reduced to 40% with SPC and GABA or SB while maintaining performance better than a diet containing 60% FM.

Effects of puerarin on growth, liver immunity and antioxidant capacity of yellowfin seabream (Acanthopagrus latus) under oxidized fish oil stress

Puerarin, an isoflavone, exhibits protective effects against liver damage. This study investigated the effects of puerarin on the growth, liver immunity, and antioxidant capacity of yellowfin seabream fed with oxidized fish oil. A total of 135 yellowfin seabream (13.00±0.05 g) were randomly divided into nine tanks (15 fish per tank), and fed with three types of diets for 56 days: a normal control fed with 6 % fresh fish oil (NC), an experimental control fed with 6 % oxidized fish oil (OFO), and a treatment fed with 6 % oxidized fish oil and supplemented with 400 mg/kg puerarin (OFP). Results showed, oxidized fish oil decreased the growth of fish, caused liver damage, and suppressed the fish's immunity. Compared to the NC group, the weight gain (WG) and specific growth rate (SGR) of the fish in the OFO group were significantly reduced; the activities of superoxide dismutase (SOD) and catalase (CAT) in serum were significantly decreased; liver morphology showed loose cytoplasm with a large amount of fatty degeneration; the lysozyme (LZM) activity in serum and liver was significantly reduced. On the other hand, compared to the NC and OFO groups, the WG and SGR of fish in the OFP group were significantly improved. Additionally, compared to the OFO group, the serum SOD and liver CAT activities in the fish of the OFP group were significantly increased, and the MDA content in serum and liver was significantly reduced. The extensive fatty degeneration in the liver was alleviated. The LZM activity in the serum and liver of fish in the OFP group was significantly higher than that in the OFO group, returning to the levels of the NC group. Meanwhile, puerarin significantly enhanced the expression of Nrf2. In conclusion, puerarin alleviated the adverse reactions induced by oxidized fish oil and promoted the growth of yellowfin seabream.

Integrating of the domestic goat into the rice-fish coculture systems: Rice paddy yield, diet, growth parameters, and intestine microbiota of common carp Cyprinus carpio (Linnaeus, 1758)

Feeding the World while ensuring food security and biodiversity conservation is one of the sustainable development challenges. Integrating farming systems holds great promise for enhancing agricultural sustainability. To reach this goal, the domestic goat (Capra hircus) was integrated into the rice fish system. Four plots each 5 m × 10.65 m were made in two experimental systems, goat-rice-fish (GRF) and rice-fish (RF). We compared the impacts on rice productivity, fish growth performance, water quality, dietary patterns, and gut microbiota composition between both systems. On the one hand, the rice yield indicators, survival rate (SR), specific growth rate (SGR), pH temperature, dissolved oxygen (DO), total nitrogen (TN), and total phosphorus (TP) were compared. On the other hand, the frequency of occurrence (FOC) of food items of fish (Cyprinus carpio), and the microbiota communities in goat faeces (GoFe) and fish intestines were also examined and compared among both systems. The results showed that the rice yield, the number of filled spikelets per panicle, the number of panicles per land area, and the 1000-grain weight were significantly increased with the integration of goat in the rice-fish coculture system. The SR of fish under the goat-rice-fish system was 12.12% significantly higher than that of the fish under the rice-fish system, as well as the SGR of fish in the GRF system was 21.85% significantly higher than that of the rice-fish system. However, the water quality analyses indicated that the integration of goats significantly increased the concentration of TN and TP. The DO concentration in the GRF system was 25.93% lower than that in the RF system. Dietary analysis of the common carp in goat-rice fish systems revealed shifts in foraging behaviors and diet composition compared to the rice-fish system. Furthermore, the study showed higher diversity in the gut microbiota communities of fish in response to goat-rice-fish integration. In conclusion, this comprehensive investigation underscores the complex and interconnected dynamics within the goat-rice-fish integrated system. It highlights the importance of balanced management practices to harness the system's potential for improved rice yield, fish ecology, and water quality. The findings contribute to a deeper understanding of sustainable integrated farming practices and inform strategies for optimizing the productivity and ecological resilience of this integrated agroecosystem.

Evaluation of the effects of dietary cinnamaldehyde on growth and nutrient use in Nile Tilapia (Oreochromis niloticus)

Cinnamaldehyde is an active organic compound and an aromatic aldehyde substance found in cinnamon oil. It is a new feed supplement for animals that can improve growth, nutrient digestion and absorption, lipid use, and immunity. The present study evaluated the effects of dietary trans-cinnamaldehyde 98 % (CIN) on nutrient utilization, antioxidant capacity, and growth performance in Nile tilapia (Oreochromis niloticus). Juveniles used was weighing at about 19.77 ± 0.10 g received dietary CIN at different doses (0, 0.25, 0.5, 0.75, and 1.0 g/kg feed). The fish were maintained in a glass aquarium of 95 × 45 × 35 cm3 in size at a stocking density of 20 fish per aquarium and fed three times a day to clear satiation. Dietary carbohydrate digestion and absorption were significantly improved in fish fed 0.75 g/kg CIN, as indicated by increased amylase activity and glucose tolerance test. The latter was subsequently confirmed by increases in relative ir, glut4, hx and gs expression that indicated the increase in glucose absorption led to an increase in glucose utilization as an energy source and the synthesis of glycogen as an energy reserve. Interestingly, dietary CIN supplementation also resulted in the downregulation of fas, which facilitates the conversion of glucose to fatty acids, and the upregulation of cpt1a and hsl, indicating increased fatty acid oxidation for energy. CIN at a range of 0.5–0.75 g/kg improved the antioxidant status in the liver, as illustrated by elevated glutathione peroxidase and superoxide dismutase activities (both P < 0.05). Final weight, feed consumption, the specific growth rate, feed efficiency, and protein retention increased were significantly in all CIN groups, with the highest values reached in the 0.5 g/kg CIN (all P < 0.05). Based on a polynomial orthogonal analysis of the fish-specific growth rate, the optimum dosage of CIN inclusion is 0.42 g/kg.

Dietary Lycium barbarum Polysaccharide Modulates Growth Performance, Antioxidant Capacity, and Lipid Metabolism in Common Carp (Cyprinus carpio) Fed with High-Fat Diet.

To investigate the ameliorative effects and mechanism of Lycium barbarum polysaccharide (LBP) on growth performance, oxidative stress, and lipid deposition in common carp (Cyprinus carpio) fed with high-fat diets, fish with an initial weight of 5.29 ± 0.12 g were divided into five experimental groups-including normal-fat diets, high-fat diets, and high-fat diets-supplemented with LBP (0.5, 1.0, and 2.0 g/kg) for 8 weeks. The results showed that high-fat diets resulted in significant decreases in final body weight, weight gain rate, and specific growth rate of fish, as well as causing a significant decrease in hepatic total antioxidant capacity, catalase, and glutathione peroxidase activities. These changes were accompanied by a significant decrease in lipase activity and ATP level and a significant increase in malondialdehyde content. The expression levels of lipid metabolism-related genes (acetyl coenzyme A carboxylase 1, stearoyl coenzyme A desaturase 1, fat synthase, peroxisome proliferator-activated receptor-γ, fructofuranose bisphosphatase, and glucose-6-phosphatase) were also markedly elevated by high-fat diets. Supplementation with 0.5-2.0 g/kg LBP in high-fat diets improved the reduced growth performance, increased hepatic total antioxidant enzymes, catalase, and glutathione peroxidase activities, and lowered malondialdehyde level in fish fed with high-fat diets. Additionally, dietary supplementation with LBP significantly downregulated hepatic gene expression levels of acetyl coenzyme A carboxylase 1, stearoyl coenzyme A desaturase 1, fat synthase, sterol regulatory element-binding protein 1, peroxisome proliferator-activated receptor-γ, fructofuranose bisphosphatase, and glucose-6-phosphatase. In conclusion, fish fed with high-fat diets demonstrated impaired growth performance, antioxidant capacity, and lipid metabolism, and dietary supplementation with 0.5-2.0 g/kg LBP ameliorated the impairments induced by high-fat diets.

The effects of two dietary synbiotics on growth performance, hematological parameters, and nonspecific immune responses in Japanese Eel.

Feed additives have attracted increased attention in aquaculture due to their ability to modulate fish gut microbiota, resulting in improved fish growth and immunity. This study assessed the effects of two synbiotics in Japanese Eel Anguilla japonica: Bacillus subtilis with mannooligosaccharides (MOS) and Enterococcus faecium with fructooligosaccharides (FOS). Six diets, including a control (CON) diet, oxytetracycline (OTC) diet, and four synbiotic diets (B. subtilis at 1 × 106 or 1 × 107 colony-forming units [CFU]/g with MOS at 5 g/kg [BS6MO and BS7MO; collectively, BSMOS diets] and E. faecium at 1 × 106 or 1 × 107 CFU/g with FOS at 5 g/kg [EF6FO and EF7FO; collectively, EFFOS diets]), were fed to triplicate groups of 20 fish (average weight ± SD = 6.00 ± 0.07 g) for 8 weeks. Fish fed the BSMOS diets showed significantly higher weight gain, specific growth rate (SGR), and feed efficiency compared to fish fed the CON and OTC diets, but the values were not significantly different from those of fish fed the EFFOS diets. Weight gain and SGR of fish that were given EFFOS diets were not significantly different from those of fish fed all other diets. Fish fed the OTC diet showed a higher mean aspartate aminotransferase level, although the difference was not statistically significant. The myeloperoxidase activity of fish fed the BS7MO diet was significantly higher than those of fish receiving all other diets, and the superoxide dismutase activity of fish fed the BS7MO diet was also significantly higher than that of fish fed the EF7FO diet. Overall, the BSMOS synbiotic diets were significantly more effective than the CON diet in enhancing fish survival against a Vibrio anguillarum challenge. Our findings suggest that synbiotics can be a preferable alternative to antibiotics in aquaculture.

Haematological, biochemical, enzymological changes and mitochondrial dysfunction of liver in freshwater climbing perch Anabas testudineus during their acute and chronic exposure to sodium fluoride

Anthropogenic activities are increasing fluoride concentration in watercourses. The present study focuses on the sublethal toxicity of sodium fluoride during sub-chronic and chronic time periods in the freshwater fish Anabas testudineus. The 96-hour LC50 value for fluoride was found to be 616.50 mg/L. Excessive mucous production and hyper excitability, followed by loss of balance, were seen in fish under acute fluoride exposure. Significant reduction in yield and specific growth rate of fish were assessed at 15, 30 and 45-days exposure intervals. Different bio-indicators like Hepatosomatic-index, Gonadosomatic-index and fecundity were reduced significantly in fish exposed to 10% (61.6 mg/L) and 20% (123.2 mg/L) of 96 h of LC50 values of fluoride in comparison to control. Toxicant concentrations directly correlated with parameter lowering. Fluoride exposure increased plasma glucose, creatinine, AST, and ALT and reduced total RBC, haemoglobin content, Hct (%), plasma protein, and cholesterol. Moreover, fluoride exposure significantly reduces the mitochondrial membrane potential in liver. This may result in metabolic depression, haematological, biochemical, and enzymological stress. The in-silico structural analysis predicts that fluoride may impede cytochrome c oxidase of the electron transport system, hence inhibiting mitochondrial functionality. These findings collectively highlight the urgent need for stringent regulation and monitoring of fluoride levels in freshwater ecosystems, as the subchronic and chronic effects observed in A. testudineus may have broader implications for aquatic ecosystems.

Effects of Dietary Bile Acids on Growth Performance, Lipid Deposition, and Intestinal Health of Rice Field Eel (Monopterus albus) Fed with High-Lipid Diets.

The purpose of this trial was to study the positive effects of bile acids (BAs) on growth performance and intestinal health of rice field eel fed with high-lipid diets (HLDs). Rice field eels (initial weight 17.00 ± 0.10 g) were divided into four groups, each group containing four repetitions and feeding with different isonitrogenous diet: control diet containing 7% lipid content, HLDs containing the lipid content increased to 13%, HLDs supplementing with 0.025% BAs and 0.05% BAs, respectively. After 8 weeks, compared control group, the fish fed HLDs had no significant effect on weight gain rate and specific growth rate (P > 0.05), but increased the lipid deposition in tissues and intestinal lipase activity, and damaged to intestinal oxidative stress, inflammatory response, physical barrier, and structural integrity (P < 0.05). Dietary BAs significantly increased weight gain rate and specific growth rate in fish fed with HL diets (P < 0.05) and reduced feed conversation rate (P < 0.05). Further, the eels fed with BAs reduced the total lipid content in liver, muscle, and whole body (P < 0.05). Dietary BAs decreased the activity of intestinal lipase (P < 0.05). Meanwhile, BAs supplemented in HLDs improved intestinal antioxidant capacity through increasing the activities of T-SOD (total superoxide dismutase), GSH-PX (glutathione peroxidase), CAT (catalase), T-AOC (total antioxidant capacity), whereas reducing MDA (malondialdehyde) content (P < 0.05). Moreover, dietary BAs regulated the mRNA expression related to inflammatory response, oxidative stress, and physical barrier in intestine, such as tnf-α, il-8, tlr-8, il-10, nrf2, keap1, claudin12, and claudin15 (P < 0.05). Dietary BAs supplementation also enhanced the intestinal structural integrity characterized by increased fold height and lamina propria width (P < 0.05). This study showed that dietary BAs supplemented in HLDs (13% lipid) could increase the growth performance of rice field eel, reduce lipid deposition in tissues and whole body, and enhance intestinal health.

Growth performance, gut microbiota composition, health and welfare of European sea bass (Dicentrarchus labrax) fed an environmentally and economically sustainable low marine protein diet in sea cages

The large use of fish meal/fish oil in carnivorous fish feeds is the main concern regarding environmental sustainability of aquaculture. Here, we evaluated the effects of an innovative diet, designed to be (1) environmentally sustainable by lowering the marine protein content while being (2) cost effective by using sustainable alternative raw materials with acceptable cost and produced on an industrial scale, on growth performance, gut microbiota composition, health and welfare of European sea bass (Dicentrarchus labrax), a key species of the Mediterranean marine aquaculture, reared in sea cages. Results show that the specific growth rate of fish fed the low marine protein diet was significantly lower than those fed conventional diet (0.67% vs 0.69%). Fatty acid profile of fillets from fish fed a low marine protein diet presented significant lower n-6 and higher n-3 content when compared to conventional ones. Then, a significant increase in the abundance of Vibrio and reduction of Photobacterium were found in the gut of fish fed with the low marine protein diet but effects on sea bass health needs further investigation. Finally, no major health and welfare alterations for fish fed the low marine protein diet were observed, combined with a potential slight benefit related to humoral immunity. Overall, these results suggest that despite the low marine protein diet moderately affects growth performance, it nevertheless may enhance environmental and economic sustainability of the sea bass aquaculture.

Effect of substituting fish meal with various by-product meals of swine-origin in diet on olive flounder (Paralichthys olivaceus)

The increased global market value of fish meal (FM) and the overfishing of wild fishery resources have boosted efforts to identify protein sources that can be cheaply and reliably supplied as an alternative to FM, which is commonly used as a main protein source in fish diets. Numerous studies over the years have demonstrated that animal by-product meals are the effective alternatives for FM in fish diets. This study aimed to elucidate the effect of substituting FM with various by-product meals of swine-origin in diet on growth, feed utilization, chemical composition, plasma biochemical parameters, and superoxide dismutase (SOD) and lysozyme activity of juvenile olive flounder (P. olivaceus). All experimental diets were formulated with five isonitrogenous (56.5%) and isolipidic (10.0%) diets. The control (Con) diet included 65% FM and 12% dehulled soybean meal as the protein sources and 4.2% fish oil as a lipid source. Thirty percent of FM was replaced with plasma powder, heme powder, globin powder, and pork greaves meal, named as the PP, HP, GP, and PM diets, respectively. Three hundred and seventy-five juvenile (9.2 ± 0.01 g; mean ± SD) fish were placed into 15 flow-through tanks with three replicates. Fish were carefully hand-fed to apparent satiation twice a day for 56 days. At the end of the feeding period, weight gain and specific growth rate of fish fed the GP and PM diets were comparable to fish fed the Con diet. Feed consumption of fish fed the PP, GP, and PM diets was comparable to fish fed the Con diet. Feed utilization and condition factor of fish fed the HP diet were the lowest. Plasma biochemical parameters, chemical composition, amino acid profiles, and SOD and lysozyme activity of fish were unaffected by dietary treatments. Thus, GP and PM are the appropriate replacers for FM in the olive flounder diets, wherein 30% FM is substituted by diverse by-product meals of swine-origin.

Effects of dietary hydrolysate supplementation on growth, body composition, hematological responses, and liver histology of juvenile giant trevally (Caranx ignobilis Forsskal, 1775).

A feeding study was conducted to investigate how fish protein hydrolysate (FPH) supplementation affected the growth, feed utilization, body composition, and hematology of juvenile giant trevally (Caranx ignobilis Forsskal, 1775). Seven isonitrogenous (52% protein) and isocaloric diets (10% lipid) were formulated, wherein shrimp hydrolysate (SH) and tuna hydrolysate (TH) were used to replace fishmeal at inclusion levels of 0 (control), 30, 60, and 90 g/kg and labeled as control, SH30, SH60, SH90, TH30, TH60, and TH90, respectively. Each diet was fed to triplicate groups of juvenile giant trevally for 8 weeks. The results showed higher final body weight and specific growth rate in fish fed SH30, SH60, TH30, and TH60 than fed control diet. No difference was observed in feed intake, but reduced feed conversion ratio (FCR) was found in fish fed SH30, SH60, TH30, and TH60, demonstrating these diets improved feed utilization. TH90 caused deposition of lipid droplet in the hepatocyte, a sign of liver damage. Total monounsaturated fatty acids, polyunsaturated fatty acids (PUFA), and highly unsaturated fatty acids in fish were not affected by FPH supplementation. Fish fed TH30 showed lower ∑n - 3 PUFA than the fish fed remaining dietary treatments. The elevated serum protein was seen in fish fed control, SH30, SH60, and TH30, demonstrating that these diets were beneficial for the innate immune response in giant trevally. The results indicate that TH and SH could be incorporated into diets of giant trevally at 30-60 g/kg, replacing 7%-13% fishmeal with enhanced growth and health benefits.

Effects of chronic saline-alkaline stress on gill, liver and intestinal histology, biochemical, and immune indexes in Amur minnow (Phoxinus lagowskii)

The need to maximize the efficiency with which saline-alkaline waters are used for aquaculture is continually increasing due to unabated increases in the global demand for aquaculture products. Here, the effects of chronic saline-alkaline stress on the growth performance, energy consumption, digestion parameters, antioxidant capacity, ion regulation, and non-specific immunity of Phoxinus lagowskii were studied. Fish were exposed to saline environments (10 parts per thousand) varying in the concentration of sodium bicarbonate [5 (T1), 7 (T2), 9 (T3), and 11 mmol L−1 (T4)]. We observed no significant differences in the weight gain and specific growth rate of fish in environments varying in alkalinity concentrations. Exposure to saline-alkaline stress resulted in a decrease in gills LH (lamellar height) and an increase in LT (lamellar thickness) and intestines VH (villous height) in P. lagowskii. The mean corpuscular hemoglobin concentration; mean corpuscular volume; serum albumin and total protein content; the activity of liver acid phosphatase, alkaline phosphatase, and alanine transaminase; and the messenger RNA (mRNA) expression levels of liver TNF-α, which encodes tumor necrosis factor-α, were significantly higher in the T4 group than in the control and other groups. Exposure to saline-alkaline stress also induced a strong antioxidant response that enhanced cellular defenses. Levels of serum glucose and triglycerides, lipase activity, and the expression of Glut-1 in the intestine significantly increased following exposure to saline-alkaline stress. The activity of Na+/K+-ATPase and Ca2+-Mg2+-ATPase and mRNA expression levels of Na+/H+ exchanger isoform 3 in the gills were significantly higher in the saline-alkaline treatments than in the control group. These findings, coupled with the fact that no mortality was observed, suggest that P. lagowskii could be cultured in saline-alkaline waters, and the optimal alkalinity concentration was <11 mmol L−1. Our study is the first to characterize the effects of exposure to saline-alkaline stress on the histological, biochemical, and immunological parameters of P. lagowskii. Our data indicate that P. lagowskii can adapt rapidly to saline-alkaline environmental stress, suggesting that P. lagowskii could be cultivated at commercial scales in saline-alkaline waters.

Modelling the effect of prebiotics, probiotics and other functional additives on the growth, feed intake and feed conversion of European sea bass (Dicentrarchus labrax) juveniles

Dietary supplementation of aquafeeds with functional additives is a commonly employed strategy in order to reduce the potential negative effects associated to fishmeal (FM) and fish oil (FO) replacement by alternative protein and oil sources. Nevertheless, the wide variety of functional ingredients with different bioactive properties hinders the selection of appropriate dietary supplementation strategies on feed formulation. The present study aimed to develop an observational multiple-linear regression (MLR) model to identify the effects of a variety of functional ingredients supplementation on European sea bass juveniles (Dicentrarchus labrax) growth performance and feed utilization. A literature survey was conducted gathering a total of 61 dietary treatments. The functional ingredients were classified in three main groups, namely, “probiotics”, “prebiotics” or “others” (including plant derived compounds such as essential oils, extracts and powders). Three different MLR were obtained and validated, allowing to describe the effects of functional ingredients supplementation on fish specific growth rate (SGR) (with a final R-squared (R2) = 0.96, adjusted R-squared (adj R2) = 0.92 and a p-value= 7.21E-08)), fish feed intake (FI) (R2 = 0.97, adj R2 = 0.95 and a p-value= 5.42E-12)) and fish feed conversion ratio (FCR) (R2 = 0.90, adj R2 = 0.80 and a p-value= 2.02E-05)). MLR model trimming, allowed the detection of a significant positive correlation (cor) between dietary prebiotics supplementation and SGR (cor= 0.32, p-value= 8.52E-04). On the contrary, prebiotic supplementation presented a negative correlation with fish FI (cor= −0.44, p-value= 6.27E-05) and FCR (cor= −0.41, p-value= 8.96E-05).

Effects of Different Feeding Frequency on the Growth, Feed utilization and Body Composition of Juvenile Eel Anguilla japonica in Semi-RAS(Recirculating Aquaculture System)

A feeding trial was conducted to investigate the effect of feeding frequency on the growth performance and body composition of juvenile eel, Anguilla japonica. Duplicate groups of fish (initial fish weight, 0.93 g/fish) were fed to apparent satiation at one, two, three, or four meals per day for 8 weeks. The results of the present study showed that weight gain and specific growth rate of fish fed one meal per day were significantly lower than those of fish fed three and four meals per day, were not affected by two meals per day. Daily feed intake of fish fed one meal per day was significantly lower than that of fish fed four meals per day, was not affected by two meals and three meals per day. Feed efficiency, daily protein intake and protein efficiency ratio were not affected by feeding frequency. The moisture, crude protein, crude lipid and crude ash were not affected by feeding frequency. Consequently, the present results suggested that optimum feeding frequency of juvenile eel (average weigth 0.9 to 3 g) is three meals per day.

반순환여과시스템내에서 사료 공급 횟수가 붕어(Carassius auratus) 치어의 성장, 사료 이용성 및 체조성에 미치는 영향

A feeding trial was conducted to investigate the effect of feeding frequency on the growth performance and body composition of juvenile crucian carp, Carassius auratus. Duplicate groups of fish (initial fish weight, 4.7 g/fish) were fed to apparent satiation at one, two, three, or four meals per day for 10 weeks. The results of the present study showed that weight gain and specific growth rate of fish fed one meal per day were significantly lower than those of fish fed three and four meals per day, were not affected by two meals per day. Daily feed intake and daily protein intake were significantly increased following to an increasing of feeding frequency until three meal per day. Feed efficiency and protein efficiency ratio were not affected by feeding frequency. The crude lipid was significantly increased following to an increasing of feeding frequency. Consequently, we can conclude that the optimum feeding frequency of juvenile crucian carp appeared three meals per day

Practical low-fishmeal diets for rainbow trout (Oncorhynchus mykiss) reared in RAS: Effects of protein meals on fish growth, nutrient digestibility, feed physical quality, and faecal particle size

To evaluate strategies for optimizing waste in recirculating aquaculture systems, 1020 rainbow trout (initial live weight 17.2 ± 7.50 g/fish) were distributed into 12 tanks after 21 d of acclimation and fed during 84 days with four practical diets (crude protein: 49% DM; crude fat 26% DM; gross energy: 23 MJ kg-1) containing different rates of fishmeal and alternative protein meals, i.e. Diet FM (307 g kg-1 fishmeal, 61.2 g kg-1 poultry by-product meal); diet PBM (183 g kg-1 fishmeal, 168 g kg-1 poultry by-product meal); diet FeM (198 g kg-1 fishmeal, 61.2 g kg-1 poultry by-product meal, 76.5 g kg-1 hydrolysed feather meal); diet FeM+RM (171 g kg-1 fishmeal, 61.2 g kg-1 poultry by-product meal, 76.5 g kg-1 hydrolysed feather meal, 60.4 g kg-1 rapeseed meal). High structural integrity of extruded pellets and low oil leakage were measured in all diets, while the lowest water turbidity at 15 min after feed administration was recorded for FeM diet (2.7 vs. 12.7 mg L-1; p < 0.05). Diets did not affect fish specific growth rate (2.16% d-1). The lowest apparent digestibility of protein was measured with diet FeM (79.6%) and the highest with diet PBM (86.0%) (p < 0.001); apparent digestibility of lipids was higher in fish fed diets FM and PBM than the other diets (84.4% and 85.5% vs. 66.4% vs. 71.1%; p < 0.001). Fish fed diet PBM showed a higher percentage of retained faeces at mesh sizes 0.5–0.8 mm (33% vs. 30%; p < 0.005) and 0.3–0.5 mm (64% vs. 59%; p < 0.001) compared with the other diets. The replacement of fishmeal with poultry by-product- meal had positive effects on nutrient digestibility and faecal particle size. The replacement with hydrolysed feathers and rapeseed meals impaired nutrient digestibility but had positive implications for water turbidity.

Growth of Clarias Gariepinus Juveniles Reared in Soilless Tanks in the Republic of Congo

The present study was conducted to assess the growth of Clarias gariépinus fingerlings introduced in Congo to improve local fish production. Fish farming is part of the concerns of the Congolese government to improve food security and savings of fish farmers. The objective of the study was to evaluate the growth of Clarias gariepinus juveniles reared in above ground tanks. A total of 60 juveniles of Clarias gariepinus of average weight (17±0.5g) were divided into two tanks. The following results were obtained: final average weights, weight gains, daily average gains and specific growth rate of fish from tank 1 (77.78± 21.74g); (61.25g); (2.04g/d); (2.24%g/d); those of fish from tank 2 of (68.45±15.48g); (50.38g); (1.68g/d); (1.93%g/d). As for the survival rates, they were (76.76%) for tank 1 and (66.66%) for tank 2. It was found that the fish in tank 1 had a significantly high survival rate, average final weight and weight gain (p ˂0.05) compared to the fish in tank 2. The study showed a good level of growth of Clarias gariépinus juveniles in artificial environment with an ability to adapt to the environmental conditions of the country.

반순환여과시스템내에서 먹이종류가 1년생 쏘가리(Siniperca scherzeri)의 성장, 사료이용 및 체조성에 미치는 영향

This study compared the effects of diets consisting of moist pellet (MP), frozen food (FF) and live food (LF) on the growth, feed utilization and whole body composition on the mandarin fish Siniperca scherzeri. Three replicated groups of 45 fish each (initial mean weight 106 g) were fed one of three experimental diets for 12 weeks. At the end of the feeding trial, weight gain and specific growth rate of fish fed the FF and LF diets were higher than those of fish fed the MP (P0.05). Feed efficiency of fish fed the FF and LF were higher than those of fish fed the MF (P0.05). Proximate composition of fish were not affected by diets (P0.05). Plasma chemical composition of fish were not affected by diets (P0.05). This suggests that frozen food (FF) can be suitable to feed growing mandarin fish.