Growth Performance Of Fish Research Articles

Impact of dandelion polysaccharides on growth and immunity response in common carp Cyprinus carpio

Natural products have gained considerable attention for improving fish growth performance and immunity to enhance disease resistance. This study evaluated the effect of dandelion polysaccharides (DP) on skin mucosal immune parameters, immune-related gene expression, and susceptibility to pathogen challenge in the Common carp Cyprinus carpio. Diets containing four different concentrations of DP (g Kg−1):0 g [basal diet], 0.5 g [D1], 1.5 g [D2], 2.5 g [D3], and 4.0 g [D4] were fed to the carp (average weight: 13.92 ± 0.83 g) for eight weeks. Growth parameters were analyzed four and eight weeks after feeding. Immunological, hematological, and antioxidant parameters were examined eight weeks post-feeding. Growth performance was significantly higher on D3, with a final weight gain of 71.48 ± 1.57 g and a specific growth rate of 3.06 ± 0.12. Among hematological parameters examined, erythrocyte, hematocrit, and mean corpuscular volume (MCV) levels were significantly higher in D3. Skin mucosal immune parameters, such as lysozyme (31.04 ± 1.02 Unit mL−1), alkaline phosphatase (122.6 ± 3.8 IU L-1), and protein level (10.6 ± 0.74 mg mL−1) were significantly higher in D3, while peroxidase activity was higher in D4. Furthermore, SOD activity was higher in D2–D3, whereas catalase activity was higher in D2–D4 (P < 0.05) than in the control. Malondialdehyde level decreased significantly in D3 (5.43 ± 0.36 nmol mL−1); whereas, serum ALT and AST levels were significantly lower on D2-D4. Intestinal tight-junction-related genes ZO-1 and Claudin 7 were significantly higher in the DP-fed groups; however, DP had no significant effect on claudin 3. Occludin expression was higher (p < 0.05) on D3 only. Pro-inflammatory cytokines (IL-1β and TNF-α) and IFN–γ strongly upregulated in the head kidney at D3. Conversely, the expression of the anti-inflammatory cytokine interleukin-10, HSP70, and TOR were considerably downregulated in D3. Fish from D3 exhibited markedly higher relative post-challenge survival (66.67%) against Aeromonas hydrophila challenge. The results of the present study suggest that dietary supplements of DP at 2.5 g kg−1 can significantly improve the growth performance, skin mucosal, and serum antioxidant parameters, and strengthen the immunity of C. carpio. Therefore, DP is a promising food additive for carp aquaculture.

Estimation of the Optimum Dietary Protein to Lipid Ratio in Juvenile Pengze Crucian Carp (Carassius auratus Var. Pengze)

An 8-week feeding experiment was conducted to evaluate the effect of dietary protein to lipid ratio on fish growth performance, digestive enzyme activity, body composition, serum biochemistry, immunity, and antioxidant capacity of Carassius auratus var. Pengze juveniles. Nine experimental diets were formulated in a 3 × 3 factorial design to contain three protein levels (30%, 35%, and 40%) and three lipid levels (5%, 8%, and 11%), with protein-to-energy (P/E) ratios ranging 19.2–27.1 mg/kJ and named as Diet 1 (30/5), Diet 2 (30/8), Diet 3 (30/11), Diet 4 (35/5), Diet 5 (35/8), Diet 6 (35/11), Diet 7 (40/5), Diet 8 (40/8), and Diet 9 (40/11), respectively. Each diet was randomly assigned to triplicate groups of 20 fish per cylindrical fiberglass tank. The fish fed with Diet 4 had the highest specific growth rate (SGR) among the 9 groups. The whole-body lipid content increased significantly with increasing dietary lipid levels regardless of dietary protein content ( P &lt; 0.05 ), whereas moisture content showed an opposite trend ( P &lt; 0.05 ). The highest values of activities of serum lysozyme (LZM) and alkaline phosphatase (AKP) were detected in the fish fed Diet 4 (35/5), whereas malondialdehyde (MDA) was lowest in the fish fed Diet 4. In addition, serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were the lowest, while high-density lipoprotein (HDL-C) and high-density lipoprotein to total cholesterol ratio (HDL-C/TC) were the highest in the Diet 4 group. The results indicate that a combination of 35.1% protein and 5.1% lipid with dietary CP/GE (mg/kJ) ratio of 24.0 is optimal for the culture of Carassius auratus var. Pengze juveniles.

Transcriptomic Analysis of the Liver and Brain in Grass Carp (Ctenopharyngodon idella) Under Heat Stress.

Temperature is a major environmental factor that influences growth, development, metabolism, and physiological performance in fish. Grass carp (Ctenopharyngodon idella) is a highly productive fish in freshwater culture. To understand the molecular mechanism of grass carp under heat stress, we used RNA-Seq to analyze the liver and brain transcriptome of 12 libraries constructed from high-temperature (36 °C) and control (28 °C) groups. We obtained 42.49 and 42.57GB of clean data from six liver and six brain libraries, respectively, and identified 2,534 genes that were differentially expressed in liver tissue and 1622 in brain tissue (P < 0.05). According to KEGG analysis, significant differences occurred in the expression of genes involved in metabolic and immune pathways, such as the cAMP signaling pathway, apoptosis, calcium signaling pathway, lipid metabolism, and protein processing in endoplasmic reticulum and peroxisome proliferator-activated receptor signaling pathways. This study revealed that high temperature enhanced lipid metabolism, reduced fatty acid synthesis, and disrupted the immune system of grass carp. These results investigated the molecular regulation of heat stress in grass carp and provided valuable information for the healthy culture of grass carp under high temperatures.

Insect meals in feeds for juvenile gilthead seabream (Sparus aurata): Effects on growth, blood chemistry, hepatic metabolic enzymes, body composition and nutrient utilization

Alternative and sustainable fish diets are required by modern aquaculture. We investigated the possibility of using insect (Tenebrio molitor TM, Hermetia illucens HI or Musca domestica MD) larvae meals (as 19.5% of the feed formulation) to replace 30% of the in the fish meal (FM) in a gilthead seabream (Sparus aurata) feed formulated to contain 65% FM. The feeds were isonitrogenous (ca 57% crude protein of dry matter) isolipidic (ca 17% lipid dry matter) and isoenergetic (ca 22 MJ kg−1 dry matter). To achieve similar energy content among the experimental diets, the fish oil inclusion was adjusted. Fish (average initial weight of 29.5 g) were fed up to apparent satiation three times a day, 7 days per week in a 93-days trial. Each diet was assigned to three 500 L tanks with fish density 2 kg m−3. Five fish from the initial population and two fish per tank were taken for whole-body composition analysis. At the end of the experimental period, nine fish per treatment were taken for the analysis of plasma metabolites and liver enzyme activities. Growth performance, feed intake, feed conversion and somatic indices of fish fed the different insect meal diets were similar to the FM fish. However, among the insect meal fish groups, the feeding with the TM diet resulted in higher specific growth rate compared to the HI diet (1.57% and 1.51% per day, respectively). The whole-body proximate composition was similar among experimental groups. Fish fed HI had the lowest fat retention (57.0% compared to 69.3–74.2%). Additionally, the HI group had also lower dry matter and energy retention (30.5% and 36.6%, respectively) compared to the FM group (33.8% and 41.5%, respectively). The whole-body saturated and mono-unsaturated fatty acids content was similar to all the experimental groups. Fish fed diets higher in fish oil (FM and HI) had higher eicosapentaenoic, docosahexaenoic and total ω-3 poly-unsaturated fatty acids content. Whole-body amino acid composition was similar among all experimental groups, while the amino acid retention exhibited significant differences. The plasma metabolites and enzyme activities as well as the hepatic lipogenic enzyme activity were not affected by the different diets. Fish fed the HI diet exhibited higher liver alanine aminotransferase (ALT) activity in comparison to the TM group. Overall, this study shows that FM can be successfully replaced by TM, HI or MD meals in 30% by weight in the diets of gilthead sea bream. Comparing insect meals, HI meal was inferior in terms of growth performance and dry matter-fat retention compared to TM and MD, respectively.

Oils Combination with Microalgal Products as a Strategy for Increasing the N-3 Long-Chain Polyunsaturated Fatty Acid Content in Fish Oil-Free Diets for Meagre (Argyrosomus regius)

Diversification of species and ingredients is essential for further developing aquaculture production. The present study aimed to evaluate the potential of a blend of microalgae oils and poultry oil as total replacers of fish oil in aquafeeds, a fast-growing species for aquaculture diversification, that was shown to require high dietary n-3 LC-PUFA levels. For that purpose, meagre juveniles ( 2.74 ± 0.01 g initial body weight) were fed one of the four experimental diets for 30 days. A control diet (FO diet) was based on 5% fish oil and 7% of rapeseed oil, whereas in the other three diets, fish oil was totally replaced by either poultry oil only (PO diet), or blending poultry oil and one of two commercial algal oils (ED and DD diets). Growth performance, tissue composition, and the expression of genes related to fatty acid biosynthesis, antioxidant defense system, and heat shock proteins were determined. Diets with blends of poultry and microalgae oils supported good growth and feed utilization of meagre. Besides, these diets maintained high DHA tissue contents and good fillet lipid quality indices, like in those fish fed the control diet containing fish oil. Furthermore, the meagre fed ED diet showed the highest expression of gpx, in agreement with the highest dietary polyunsaturated fatty acid content. These results demonstrated the good potential of blending these two commercial microalgae oils with poultry oil to completely replace fish oil cost-effectevily in diets for meagre. In contrast, PO as the sole replacer of fish oil was not able to support fish growth performance and tissue contents of n-3 LC-PUFA, leading to an increased thrombogenic index in fish fillets. Additionally, the low dietay n-3 LC-PUFA content of PO diet upregulated the relative expression offads2 while downregulating gpx compared to microalgal diets.

Dietary Arachidonic Acid (20:4n-6) Levels and Its Effect on Growth Performance, Fatty Acid Profile, Gene Expression for Lipid Metabolism, and Health Status of Juvenile California Yellowtail (Seriola dorsalis)

Arachidonic acid (ARA, 20:4n-6) fed to Seriola dorsalis juveniles at different levels was evaluated. After a seven-week feeding trial, growth performance, hepatopancreas and muscle fatty acid (FA) composition, expression of lipid-relevant genes, and blood parameters were evaluated. Four isoproteic and isolipidic experimental diets were formulated to contain 44% crude protein and 11% lipids with graded inclusion levels of ARA, 0% (Control), 0.4, 0.9, and 1.4% of the total diet. S. dorsalis juveniles (14.54 ± 0.18 g) were randomly divided into twelve tanks with fifteen animals each. The animals were hand fed three times per day to apparent satiation. Dietary treatments did not significantly affect the growth performance, SGR, FCR, and feed intake of fish. Different levels of ARA in the experimental diets directly influenced liver and muscle FA profiles, with significant changes in ARA and EPA deposition between Control treatment and 1.4%, in both tissues. The expression of arachidonate 5-lipoxygenase (alox5), acyl-CoA dehydrogenase very long chain (acadvl), carnitine O-palmitoyltransferase 1(cpt1a) was significantly affected by dietary treatments, with an expression increasing accordingly to the increasing ARA levels. In contrast, a reduction of fatty acid synthase (fas) and proliferator-activated receptor alpha (ppara) expression was significantly reduced as ARA increased in the diet. In addition, a significant reduction in blood cortisol and glucose was found at a 0.9% ARA level compared to the other treatments. Based on the performance, cortisol levels, the gene expression for eicosanoids synthesis, and lipid metabolic pathways, the present study suggests a maximum ARA inclusion of 0.9% in diets for California yellowtail juveniles, S. dorsalis.

Mulberry leaf meal: A potential feed supplement for juvenile Megalobrama amblycephala “Huahai No. 1”

This study was performed to evaluate the potential application of mulberry leaf meal (ML) and fermented mulberry leaf meal (FML) as feed supplements in aquatic animals for developing varieties of practical and economical feed ingredients. Juveniles Megalobrama amblycephala were fed a basal diet (35.7% crude protein, 10.4% crude lipid; control group) supplemented with 2.22% and 4.44% mulberry leaf meals (ML2, ML4) and fermented mulberry leaf meals (FML2, FML4) for 8 weeks. Generally, the two-way ANOVA showed the supplementation level exhibited a prominent effect on the growth performance and physiological status of fish. Furthermore, the two-way ANOVA showed the supplementary fermented mulberry leaf meal increased plasma complement 4 (C4) content (P < 0.05). The weight gain rate (WGR, 145.87%) and the specific growth rate (SGR, 1.63%) were significantly increased in FML2 group compared with the control group (P < 0.05). The muscle crude lipid content and hepatosomatic index (HSI) were higher in FML2 group than that in ML2 group (P < 0.05). The hepatic GSH content in ML4 group and CAT, T-SOD activities in FML4 group were significantly increased compared with the control group (P < 0.05). The hepatic MDA content in FML4 group was significantly decreased compared with the FML2 group (P < 0.05). Total cholesterol (TC) contents showed a significant decrease in ML4 and FML4 groups compared with the control group (P < 0.05). Regarding the gene expression, sirtiun 1 (Sirt1) gene expression was elevated in FML2 group compared with the ML2 group (P < 0.05). Compare to the control group, FML2 diet significantly increased the expression of i-kappa-B alpha (IKBα) gene in liver, and decreased the expression of forkhead box O1 α (FoxO1α), toll-like receptors 4 (TLR4) and nuclear factor-kappa B (NF-κB) genes (P < 0.05). In conclusion, 2.22% FML promoted the growth performance of M. amblycephala and enhanced the anti-inflammatory responses by inhibiting TLR4/NF-κB signaling pathway. On the other hand, 4.44% FML reduced plasma lipid content (hypolipedemic effect) and improved the hepatic antioxidant capacity of M. amblycephala.

Evaluation of different stocking densities and carbon:nitrogen ratios on growth, body composition and production performance of Labeo rohita (Hamilton, 1822) spawn in biofloc based‐nursery system

Biofloc technology (BFT) is an intensive sustainable farming technique that increases the carrying capacity of the culture system by controlling the C/N ratio. The present study aims to assess the potentiality of BFT for intensive nursery production of Labeo rohita spawn (6–8.5 mm). The assessment was done at different stocking densities, that is, 1 (D1), 2 (D2), 3 (D3), 4 (D4) and 5 (D5) spawn/L (study I) and at different C/N ratios, that is, 10:1, 15:1 and 20:1 (study II), by evaluating survival, growth, feed utilization and biochemical composition of spawn in biofloc culture system. The cultures reached at the end of 20 days showed a higher mean survival rate, that is, 89%, 91.38% and 80.4% in D1, D2 and D3 respectively. Moreover, these BFT groups exhibited spearheading growth in terms of final length, final weight and specific growth rate. The coefficient of variation and food conversion ratio was lowest in D2, but the highest production was achieved in D3. In study II, the biofloc culture (at 2 spawn/L density) with C/N ratio >15:1 effectively reduced the total ammoniacal and nitrite nitrogen and produced in situ live food adequately. In addition, the C/N ratio showed an interactive effect on the growth performance of fish by the substantial increase in final length, weight gain percentage, specific growth rate and feed utilization in C/N 20 and 15 groups than that in C/N 10 group. The crude protein and lipid level of biofloc in C/N 20 and 15 treatments was notably higher than in other treatments. The findings suggest that the BFT can be effectively applied to enhance the nursery production of L. rohita, preferably at 2–3 spawn/L stocking density and 15:1C/N ratio.

Partial and total fishmeal replacement by defatted Tenebrio molitor larvae meal do not alter short- and mid-term regulation of food intake in European sea bass (Dicentrarchus labrax)

Understanding the underlying mechanisms responsible for regulation of food intake in fish is crucial for proper formulation of aquafeeds and consequently ensure the best growth performance of fish. Over the last decade, the study of the impact of insect meal-based diets on growth performance and voluntary feed intake of several fish species has emerged, but little is known about their influence on anorexigenic potential. This is the first study evaluating short- and mid-term responses of European sea bass (Dicentrarchus labrax) fed diets not only with partial, but also with total fishmeal (FM) replacement by defatted Tenebrio molitor larvae meal (dTM). A fishmeal-based diet was used as a control (CTRL) and two other diets were formulated to include 20% and 40% of dTM, replacing 50% and 100% of fishmeal (FM), respectively. The short-term response was evaluated after the first exposure to the experimental diets, whereas the mid-term response was evaluated after 7 days of feeding. In both short- and mid-term trials, food intake was registered. Hepatic and plasmatic metabolites and the expression of hypothalamic and telencephalic neuropeptides involved in food intake were assessed 2 and 24 h post-feeding. No differences occurred in food intake levels, neither in the short- nor mid-term. In the short-term, plasmatic glucose levels increased in fish fed TM100, regardless post-feeding sampling time. In the mid-term, fish fed TM100 had the highest levels of triglycerides in liver and the lowest levels of α-amino-acids in plasma, irrespective of post-feeding sampling time. At central level, dietary treatment did not alter the expression of neuropeptide Y (npy), agouti-related protein 2 (agrp2), pro-opio melanocortin a (pomca) or cocaine- and amphetamine-related transcript 2 (cartpt2) in hypothalamus and telencephalon. The obtained results suggest that partial and total FM replacement by dTM does not influence short- and mid-term regulation of food intake in European sea bass. Nonetheless, changes observed in hepatic and plasmatic metabolite levels of fish fed TM100 may indicate alterations of intermediary metabolism in the long-term.

Dietary combination of maggot and commercial feed enhance the growth rate and feed conversion ratio of snakehead fish (Channa striata)

Snakehead fish (Channa striata) is a carnivorous freshwater fish commodity that has high economic value. However, this cultivation takes a long period due to its poor growth rate. Maggot has been proposed as a possible alternative to fish feed because it is less expensive and has nutritional value. This study aimed to determine the effect of the dietary combination of maggot and pellets on the growth rate and feed conversion ratio of snakehead fish. This study used a completely randomized design (CRD) with five treatments and four replications. The treatments were P0: 100% pellet, P1: 100% maggot, P2: 75% pellets and 25% maggot, P3: 50% pellets and 50% maggot, P4: 25% pellets and 75% maggot. The result showed a combination of pellet feed and maggot feed had a significant improvement (p<0.05) on the growth rate of snakehead fish. However, there were no significant differences in the feed conversion ratio (p>0.05). The treatment of 75% pellet feed and 25% maggot feed (P2) generated the highest growth rate of 0.154 g/day and the lowest feed conversion ratio of 3.121. It can be concluded that the combination of maggot and pellet experienced better growth performance and feed conversion ratio of snakehead fish.

Can Insect Meal Replace Fishmeal? A Meta-Analysis of the Effects of Black Soldier Fly on Fish Growth Performances and Nutritional Values.

Simple SummarySince 2007, black soldier fly meal has become the main substitute suggested in studies to replace fish meal in fish feeds. The quantitative results of these studies have been analyzed in this paper in order to assess the relevance of such substitution. The analysis focused on the impact of this insect on the growth and nutritional quality of fish. The results showed variable conclusions between studies. These variations are due to the fish species or to the protein substitution rate of the fish meal. Although no definite conclusions have been reached, it is possible to consider high levels of substitution.The search for quality alternatives to fishmeal and fish oil in the fish feed industry has occupied many researchers worldwide. The use of black soldier fly meal (BSFM) as a substitute has increased. This study evaluated the effect of this substitution on fish growth and nutritional quality through a meta-analysis of the literature. A list of studies was selected after an exhaustive literature search followed by the extraction of growth and nutritional parameters. Two random-effects models were used to estimate the differences between the experimental parameters and the controls. The results showed significant heterogeneity between studies for all parameters. The sources of heterogeneity between studies were mainly fish species and protein substitution rate. High substitutions can be considered without necessarily worrying about an adverse effect. Financial profitability studies of the fish production chain from BSFM should be carried out to validate or invalidate the economic viability of this substitution.

Effects of Diet Supplemented with Morinda citrifolia Fermented Extract on the Growth Performance and Feed Conversion Ratio of Oreochromis niloticus

The use of additives in feeds to promote the growth of farmed fish has been rapidly expanding; among these are supplements derived from indigenous plants. Here, we analyzed the effects of satiation feeding of diet supplemented with noni (Morinda citrifolia) fermented extract on the feeding rate, growth performance and feed conversion ratio of Tilapia, Oreochromis niloticus. Fish with an initial average weight of 2.83 ± 0.01 g were fed with diets supplemented with noni fermented extract at 0 (control), 100-, 200- and 300-ml kg-1 for 12 weeks. Subsequent results showed that growth rate was correlated with or dependent on the concentration of noni fermented extract in the diet. The best result for growth performance, such as weight gain, average daily growth rate and specific growth rate, was found in a fish-fed diet supplemented with noni fermented extract at 200 ml kg-1. However, the feed conversion ratio (FCR) is still higher than the control. The high FCR compared to control may be due to the anthraquinone in noni fermented extract, which decreases nutrient absorption. Fish fed with a 300 ml kg-1 noni fermented extract supplemented diet was the lowest growth performance and highest in FCR, suggesting that concentrations over 200 ml kg-1 might be detrimental to fish. Taken together, noni fermented extract can be a natural source of feed supplement to improve fish growth performance and may act as an appetite stimulant. However, due to its laxative effect, noni fermented extract supplementation should be given at appropriate levels and effective feeding management.

Effects of three feeding strategies (self‐feeders, automatic feeding and apparent satiety) on growth performance, haematological parameters, waste excretion and feed cost in Amazonian fish ( Colossoma macropomum )

A 127-day experiment was conducted to evaluate the effect of feeding strategies on juvenile tambaqui's (Colossoma macropomum) growth, body composition, haematological and biochemical parameters, excretion pattern and economic indices. Fifteen tanks randomly stocked 150 juvenile tambaqui (82.0 ± 0.8 g, mean ± SEM) subjected to three feeding strategies (n = 5): self-feeder system (T1); automatic-feeding with three set meals/day (T2) and apparent satiety with three meals/day (T3). The results revealed that fish T1 and T3 showed the best feed intake, feed conversion ratio, protein efficiency ratio and protein retention rate (p < 0.05). However, no significant differences were observed in growth, survival, haematological parameters, body composition and total ammonia nitrogen excretion among treatments (p > 0.05). Cortisol obtained a significantly higher value for fish T3 (122.92 ± 5.75 ng/ml), with a low water phosphorus value for fish T1 (0.43 ± 0.06 mg/L). Lastly, the feed cost based on the values deriving from diets revealed better indices (variable cost, unitary contribution margin and contribution margin index) for fish T1 and T3. In short, our findings suggest the benefits of using self-feeders for tambaqui aquaculture.

Effects of Formulated Fish Feed on Water Quality, Growth Performance, and Nutritional Properties of Catla Fish, Catla catla

Effects of Formulated Fish Feed on Water Quality, Growth Performance, and Nutritional Properties of Catla Fish, Catla catla

Effects of water temperature on the gut microbiome and physiology of Chinook salmon (Oncorhynchus tshawytscha) reared in a freshwater recirculating system

Climate change and global warming pose particular concerns to the aquaculture industry as water temperature is one of the most important influences of health and growth performance in poikilotherms. Despite increased recognition of the importance of the gut microbiome in fish health, knowledge of temperature effects on the holobiont and implications for aquaculture performance are still limited. We assessed the effect of water temperature in a freshwater recirculating aquaculture system on the gut microbiome and the physiology, health and growth of New Zealand's most important farmed fish, the Chinook Salmon (Oncorhynchus tshawytscha). Fish were reared at four temperatures (8, 12, 16, 20 °C) for 41 to 49 days. Health, growth and feed intake were assessed at the beginning and end of the experiment. Haematology, plasma biochemistry, histology and tissue composition (e.g. fatty acids, amino acids, chemical composition) and gut microbiota (faeces and hindgut wall mucosa) were characterized. We found that increased temperature resulted in an increase in feed intake and growth (plateauing as it approached 20 °C) but did not impact feed conversion efficiency. Gut microbiome community composition assessed from both sample types changed with increasing temperature, with the dominance of Vibrionaceae (Photobacterium phosphoreum and/or pisciola) being gradually replaced by Fusobacteriaceae (Cetobacterium somerae) and Brevenemataceae (Brevinema). A significant effect of temperature was also observed on fish histology, fatty acids, chemical composition, haematology, plasma biochemistry and several internal biometrics, with significant correlation of most of these data layers with the gut microbiota. Notably, glucose, lactate and magnesium concentration in plasma, whole-body palmitic and the sum of the saturated fatty acids, and Cetobacterium were positively associated with increased temperature. This study provides further knowledge on how the Chinook salmon holobiont is influenced by water temperature and how the changes observed relate to fish growth performance and health. These results will help make more informed decisions for monitoring fish gut microbiota and tailoring dietary requirements to rearing water temperature.

The Effects of Substituting Fishmeal Based-Diet With Plant Based-Diet on Nile Tilapia (Oreochromis niloticus) Fish Growth, Feed Efficiency and Production Cost-Effectiveness

Aquaculture started in The Gambia in 1979 but is still at a rudimentary stage. Many government and private interventions conducted on fish farming failed due to the high cost of feed. Fishmeal based diets are expensive thus using them makes many fish farming in the developing countries unprofitable businesses. There is a need to use locally available plant ingredients to develop fish feeds. This study was conducted to compare the growth, feed efficiency and production cost-effectiveness of the Nile tilapia (Oreochromis niloticus) fish fed on fishmeal-based diet (control diet) to that of the same fish fed on plant-based diet (test diet). The two isonitrogenous (30 % CP) experimental diets were tested on 0.81g Nile tilapia (Oreochromis niloticus) fry for a period of six (6) weeks. The control diet composed of fishmeal, soybean meal, cassava flour, and a blend of palm oil and fish oil premixed with mineral and vitamin supplements. The plant-based diet consisted of groundnut cake, wheat flour, brewery waste and rice bran supplemented with mineral and vitamin premixes. Regarding growth performance parameters, there were significant differences between the final mean weight, mean weight gain, percentage mean weight gain and the specific growth rate of Nile tilapia (Oreochromis niloticus) fish fed on the control diet and the plant-based diet. For feed efficiency parameters, there was significant difference between feed conversion ratio for fish fed the control diet and the plant-based diet. However, there was no difference between the fish fed the two diets with regards to the protein efficiency ratio or survival rate. The plant-based diet was inferior to the fishmeal-based diet in terms of growth and feed efficiency parameters of 0.81g Nile tilapia (Oreochromis niloticus) fry. When compared to the fish-meal based diet, the plant based-diet was more cost-effective in producing a kilogram of feed but less cost-effective in producing of a kilogram of fish. Therefore, a plant based-diet cannot replace a fishmeal based-diet without compromising Nile tilapia (Oreochromis niloticus) fish growth performance and production cost-effectiveness.

A new strategy: Dietary lipids protected the liver from hypoxia injury in multiple ways in grass carp (Ctenopharyngodon idella)

Hypoxia is becoming a non-negligible issue in aquaculture. The studies of dietary lipids mainly focused on growth performance, immune and meat quality of fish. There were scarce reports that dietary lipids can help fish resist stress, especially hypoxia stress. The objective of this study was to investigate the effects of dietary lipids on hypoxia-caused liver injury, oxidative damage, apoptosis, endoplasmic reticulum (ER) stress and autophagy of grass carp (Ctenopharyngodon idella), as well as make sure the lipid requirement of grass carp to resist hypoxia. Grass carp were fed diets containing six graded lipid levels (0%, 1.2%, 2.4%, 3.6%, 4.8% and 6.0%) for 60 days and exposed to hypoxia or normoxia for 96 h respectively. As shown in our results of grass carp, diets with proper lipid levels relieved hypoxia-induced adverse effects: (1) alleviated liver injury [decreased lactic dehydrogenase (LDH), glutamic oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activity, as well as reduced hepatic cellular vacuolation (HCV) and improved ER morphology]; (2) diminished liver oxidative damage [decreased reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl (PC) contents] and inhibited liver apoptosis (decreased caspase-3, −8 and − 9 activity); (3) relieved liver ER stress which might have connection with the inhibition of glucose regulated protein 78 (GRP78) -protein kinase R-1ike ER kinase (PERK) - eukaryotic translation initiation factor 2 subunit alpha (eIF2α) - activating transcription factor 4 (ATF4) and GRP78 - activating transcription factor 6 (ATF6) - X-box binding protein 1 (XBP1) pathways, rather than inhibition of inositol-requiring kinase1α (IRE1) pathway; (4) inhibited liver autophagy which might be related to the inhibition of the initiation [unc-51 like autophagy activating kinase 1 (ULK1)], elongation and closure [autophagy-related protein 5 (ATG5), autophagy-related protein 12 (ATG12) and light chain3II protein (LC3II)] of autophagosomes, rather than the inhibition of mitophagy and sequestosome 1 (P62) mediated degradation of substrates. In all, diets with proper lipid levels might be helpful to relieve hypoxia-induced adverse effects (injury, oxidative damage, apoptosis, ER stress and autophagy in the liver) on grass carp. Based on ROS and MDA contents of grass carp liver, we determined the optimal lipid levels to resist hypoxia-induced liver damage were 3.59% and 3.05%, respectively.

Effects of Microalgae Addition and Fish Feed Supplementation in the Integrated Rearing of Pacific White Shrimp and Nile Tilapia Using Biofloc Technology.

Simple SummaryIn biofloc technology systems, organic matter and inorganic substances accumulate in the culture unit mainly due to low water exchange, feed input, high stocking densities, and the level of organic carbon that subsequently increase the bacterial biomass. The organic and inorganic matter in suspension are maintained in a limited concentration to avoid negative effects on animal performance and water quality. This requires the occasional removal of excess solids, which produces an effluent enriched in nutrients, such as nitrogen and phosphorus. The use of integrated aquaculture in which the residues of one species are used as a source of nutrients for another species is an approach which aims to minimize this production of waste. Still, there are aspects of integrated cultures that have to be studied, such as the provision of feed for the different species. Therefore, we evaluated the addition or not of fish feed and microalgae in an integrated shrimp and fish culture regarding animal growth performance and water quality. We found that biofloc is nutritive for fish, but feed is necessary to improve its growth. Moreover, microalgae improved fish survival. However, both of factors did not affect the solids production.This study aims to evaluate a Pacific white shrimp and Nile tilapia integrated system using biofloc technology with or without the addition of the microalgae Scenedesmus obliquus and with or without fish feed supplementation in a two-factor 62-day experiment. The shrimp (2.16 ± 0.01 g) were reared under a density of 400 shrimp m−3 and the fish (1.53 ± 0.12 g) were reared under a density of 522 fish m−3. The microalgae was added to the culture water two times a week. Growth performance, sludge production, and water microbiology were evaluated. Fish feed and the microalgae addition improved fish final biomass in 58% and 14%, respectively (p < 0.05). Fish survival was significantly higher when microalgae was added (93.9 ± 1.8%) compared with the treatments without microalgae addition (86.2 ± 7.6%) (p < 0.05). The yield of the overall system was higher in the treatments with fish feed supplementation (4.2 ± 0.2 kg m−3) compared with no addition (3.9 ± 0.2 kg m−3) (p < 0.05). These results suggest that fish feed supplementation at the rate of 1% of the biomass and microalgae inoculation can improve fish growth performance and system yield, without affecting sludge production and water microbiology. This work is an expansion of a conference paper with the same title.

Açai palm, Euterpe oleracea, seed for aquaponic media and seedling production

The overexploitation of limited resources combined with the excess of residue produced by agroindustry are worldwide concerns that are steering human activities towards cleaner and more efficient production methods. This is the first study to verify the possibility of using discarded açai seed as growth media for water biofiltration and seedling production in an Amazonian aquaponic system with tambaqui, Colossoma macropomum. To conduct the evaluation, three flooding levels (5,10 and 15 cm) with constant flow through the açai seed bed (13 cm depth) and a control (without açai seed) were performed for 30 days and the effects on water quality, vegetable and fish growth performance were analyzed. After 28 days, mean total ammonia was lower than 1 mg L−1 in treatments with açai seed, and was higher than 5 mg L−1 at control during the entire experiment. While phosphate and nitrite were not significantly affected, nitrate was lower at 15 cm of water flow. The açai seed decreased dissolved oxygen, total dissolved solids and conductivity, and increased pH and alkalinity. After 22 days, superficial açai germination was 2.63 and 3.07 times higher at the 10 cm flood level than at 5 and 15 cm respectively, though higher seedling growth was observed at 5 cm. After 30 days, no significant differences were observed in tambaqui performance, which reached more than 1 kg and at a rate of almost 10 g per day. In this context, açai seed is capable of removing nitrogen compounds, producing a high quantity of early seedlings and without negatively affecting tambaqui growth.

Dietary Sodium Butyrate Supplementation Attenuates the Detrimental Effects of High‐Fat Diets on Growth Performance, Liver Health, and Disease Resistance in Grass Carp

AbstractAn 8‐week experiment was conducted to investigate the effects of sodium butyrate (NaBT) inclusion in high‐fat (HF) diets on growth performance, liver health, and disease resistance in Grass Carp Ctenopharyngodon idella. Three diets (Control diet containing crude lipid at 58 g/kg, HF diet with 108‐g/kg crude lipid, and NaBT diet with 108‐g/kg crude lipid and 1‐g/kg NaBT) were randomly assigned to nine tanks with 30 fish (9.50 ± 0.06 g) in each tank. After the feeding trial, disease resistance was assessed by injecting the fish with Aeromonas hydrophila. Compared to the Control diet group, the HF diet group showed lower specific growth rate, feed efficiency, and survival rate (15.7%) after the A. hydrophila challenge; significantly higher activity levels of alanine aminotransferase and aspartate aminotransferase in plasma; higher malondialdehyde content; higher messenger RNA (mRNA) expression of interleukin‐8, cysteinyl aspartate specific protease (caspase) 9, and caspase 3; lower activity level of glutathione peroxidase; and lower mRNA expression of nuclear factor erythroid 2‐related factor 2 in liver. However, the NaBT diet significantly increased fish growth performance and survival rate (39.7%) after the A. hydrophila challenge and reduced hepatic oxidative stress, inflammation, and apoptosis compared to the HF diet. In conclusion, NaBT can ameliorate the detrimental effects of HF diets on fish growth performance and fish health.