Growth Performance Of Fish Research Articles

Effects of dietary protein substitution of fishmeal with black soldier fly larval meal on growth and physiological responses of juvenile striped catfish, Pangasianodon hypophthalmus

A 10-week feeding trial was conducted to determine the effects of dietary black soldier fly larval meal (BSFLM) on growth performances, digestive enzyme activity, haematological responses and muscle growth-related gene expression of juvenile striped catfish (Pangasianodon hypophthalmus). Six isonitrogenous and isolipidic diets were formulated with BSFLM to replace fishmeal at 0 per cent (T0), 20 per cent (T20), 40 per cent (T40), 60 per cent (T60), 80 per cent (T80) and 100 per cent (T100). A total of 540 fingerlings were randomly distributed into 18 tanks and fed thrice a day. Growth performance and feed utilization of fish fed T20, T40 and T60 diets were not significantly different from T0 diet. However, increasing the percentage of fishmeal replacement with BSFLM to 100% at an inclusion level of 292 g/kg resulted in a substantial reduction in growth and feed efficiency of striped catfish. Fish fed T80 and T100 diets had significantly lower whole-body crude protein, crude lipid, total cholesterol and triglyceride value than fish fed other experimental diets, while dietary inclusion of BSFLM had no significant effect on the whole-body amino acid profile, haematological responses and intestinal and liver protease and amylase activity of striped catfish. However, lipase activity was increased in fish fed T80 and T100 diets. T80 and T100 hepatocytes were shown to have greater congestion in histology than other groups. The relative expression of MyoD and myogenin was significantly maximized in fish fed the T60 diet. Fishmeal may be replaced with BSFLM up to 60 per cent at an inclusion level of 174 g/kg in the diet of juvenile striped catfish.

Effect of dietary supplementation of astaxanthin and beta-carotene on colouration, growth and survival in pearlspot (Etroplus suratensis) fingerlings under controlled conditions

The pearlspot (Etroplus suratensis) is dull greenish black color in and less attractive cichlid fish to the customer. The present study investigated the effects of different concentration of astaxanthin and beta-carotene incorporated feeds on pigmentation of E. suratensis skin and flesh. Seven carotenoid content incorporated diets were formulated at different concentrations of axtaxanthin (100 ppm, 200 ppm and 300 ppm) and beta-carotene (30 ppm,40 ppm and 50 ppm). During the experimental period (60 days), the fishes were fed at the rate of 5% of body weight per day. The highest mean weight gain was observed in fishes fed with 300 ppm of astaxanthin (24.06+0.01 g) and 50ppm of beta-carotene (21.56+0.01 g), compared to other treatments and control. Significant improvement in the growth parameters were recorded in the experimental fishes than control. The highest carotenoid content was found in fishes fed with 300 ppm of astaxanthin and 50 ppm of beta-carotene compared to other treatments and control. There was no significant difference (P>0.05) in the growth performance of fishes by dietary carotenoid supplementation. However, significant (P<0.05) difference was observed in the flesh and skin of fishes fed with 300 ppm astaxanthin and 50 ppm beta-carotene treatment. Pearlspot fingerlings fed with carotenoid content incorporated diets showed better growth performance and feed utilization. Dietary carotenoid content influenced digestive enzyme activity, haemotological and biochemical responses. In order to improve the consumer preference and the market value of E. suratensis, these flesh and skin colouration could be improved by feeding with diets containing astaxanthin (300 ppm) and beta-carotene (50 ppm).

Effects of Mulberry (Morus alba L.) Leaf Extracts on Growth, Immune Response, and Antioxidant Functions in Nile Tilapia (Oreochromis niloticus)

Abstract This study evaluates how white mulberry (Morus alba L.) leaf extracts affect the growth, antioxidant activity, and immune response in Nile tilapia Oreochromis niloticus. Mulberry leaf extracts were obtained through aqueous extraction (AE) and ethanol extraction (EE). Powder of mulberry leaf (PML) was added directly to feed and compared with the effects of feeds supplemented with the different extracts. Fish were divided into eight groups for an 8-week feeding trial where they were fed the basal diet or supplemented with 10% PML, 10% AE, 20% AE, 40% AE, 10% EE, 20% EE, or 40% EE. The inclusion of mulberry leaf extract obtained with either method showed better effects on fish growth performance, antioxidant activities and acid phosphatase activity (ACP) in serum, immune cytokine expression, and intestinal morphology as compared with controls or fish fed the 10% PML diet. The specific growth rate was significantly higher in the 10% AE, 10% EE, and 20% EE groups compared with all other groups (P&lt;0.05). Catalase activity was significantly greater in most groups fed an extract, and in the 10% PML group, when compared with controls. Similarly, ACP, interleukin (IL)-1, and IL-2 expression was significantly increased in groups fed an extract, and in the 10% PML group, when compared with controls (P&lt;0.05). IL- 1, IL-2, IL-10, and Toll-like receptor 2 expression was significantly greater in the 10% EE group than in the 10% PML and 10% AE groups (P&lt;0.05). Villus length in the middle intestine was significantly increased in the 10% AE and 10% EE groups compared with controls and the 10% PML group (P&lt;0.05). Thus, 10% mulberry leaf ethanol extract added to feed is recommended for enhancing the growth rate and health of cultured Nile tilapia.

Dietary Glutamine Inclusion Regulates Immune and Antioxidant System, as Well as Programmed Cell Death in Fish to Protect against Flavobacterium columnare Infection.

The susceptibility of animals to pathogenic infection is significantly affected by nutritional status. The present study took yellow catfish (Pelteobagrus fulvidraco) as a model to test the hypothesis that the protective roles of glutamine during bacterial infection are largely related to its regulation on the immune and antioxidant system, apoptosis and autophagy. Dietary glutamine supplementation significantly improved fish growth performance and feed utilization. After a challenge with Flavobacterium columnare, glutamine supplementation promoted il-8 and il-1β expression via NF-κB signaling in the head kidney and spleen, but inhibited the over-inflammation in the gut and gills. Additionally, dietary glutamine inclusion also enhanced the systematic antioxidant capacity. Histological analysis showed the protective role of glutamine in gill structures. Further study indicated that glutamine alleviated apoptosis during bacterial infection, along with the reduced protein levels of caspase-3 and the reduced expression of apoptosis-related genes. Moreover, glutamine also showed an inhibitory role in autophagy which was due to the increased activation of the mTOR signaling pathway. Thus, our study for the first time illustrated the regulatory roles of glutamine in the fish immune and antioxidant system, and reported its inhibitory effects on fish apoptosis and autophagy during bacterial infection.

Effects of black soldier fly (Hermetia illucens) enriched with Schizochytrium sp. on zebrafish (Danio rerio) reproductive performances

Nutrient quality, with emphasis on lipid and fatty acid composition of broodstock diet, is one of the major dietary factors influencing fish oocytes maturation, reproductive success and offspring quality/survival. The Black Soldier Fly (BFS) (Hermetia illucens) is a valuable insect species characterized by a balanced essential amino acid profile comparable to fishmeal and has been demonstrated to be an eco-friendly and low-cost protein source in fish diets. However, as regards lipids, BFS is usually characterized by a poor content in polyunsaturated fatty acids which are essential for fish during critical life-cycle stages including oocyte maturation and reproduction.In the present study, full-fat enriched BSF prepupae meal was obtained from BSF larvae reared on coffee by-product (coffee silverskin) enriched with 10% of Schizochytrium sp. Successively, five experimental diets containing different full-fat enriched BSF prepupae meal inclusion levels (corresponding to the 0, 25, 50, 75 and 100% fish meal replacement) were tested during a six-month feeding trial performed on zebrafish (Danio rerio) to investigate, for the first time, the physiological effects on female fish growth, stress response, lipid metabolism and reproductive performances. A multidisciplinary approach including biometric, gas-chromatographic, histological and molecular analyses was used during the present study to have a comprehensive overview of fish responses to the test diets. Results highlighted that up to 50% of fish meal replacement with enriched BSF meal did not impair zebrafish physiological responses while higher replacement levels (75 and 100%) negatively affected fish stress response, oocytes maturation stages, spawning and hatching success.

Effects of Replacement of Dietary Fishmeal by Cottonseed Protein Concentrate on Growth Performance, Liver Health, and Intestinal Histology of Largemouth Bass (Micropterus salmoides).

An 8-week feeding trial was conducted to explore the effects of replacement of dietary fishmeal by cottonseed protein concentrate (CPC) on growth performance, liver health, and intestine histology of largemouth bass. Four isoproteic and isolipidic diets were formulated to include 0, 111, 222, and 333 g/kg of CPC, corresponding to replace 0% (D1), 25% (D2), 50% (D3), and 75% (D4) of fishmeal. Two hundred and forty largemouth bass (15.11 ± 0.02 g) were randomly divided into four groups with three replicates per group. During the experiment, fish were fed to apparent satiation twice daily. Results indicated that CPC could replace up to 50% fishmeal in a diet for largemouth bass without significant adverse effects on growth performance. However, weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE), and condition factor (K) of the largemouth bass were significantly decreased when 75% of dietary fishmeal that was replaced by CPC. The whole body lipid content was increased with the increasing of dietary CPC levels. Oil red O staining results indicated that fish fed the D4 diet showed an aggravated fat deposition in the liver. Hepatocytes exhibited serious degeneration, volume shrinkage, and inflammatory cells infiltration in the D4 group. Intestinal villi appeared shorter and sparse with severe epithelial damage in the D4 group. The transcription levels of anti-inflammatory cytokines, such as transforming growth factor β (tgf-β), interleukin 10 (il-10), and interleukin 11 β (il-11β), were downregulated in the D4 group. The lipid metabolism-related genes carnitine palmitoyl transferase 1 (cpt1), peroxisome proliferator-activated receptor α (pparα), and target of rapamycin (TOR) pathway were also significantly downregulated in the D4 group. It was concluded that suitable replacement of fishmeal by less than 222 g CPC/kg diet had a positive effect on growth performance of fish, but an excessive substitution of 75% fishmeal by CPC would lead to the suppressed growth, liver inflammation, and intestinal damage of largemouth bass.

Effect of fish waste hydrolysate on growth performance and health status of milk fish (Chanos chanos) and its potential to reduce feed

The study was undertaken to unravel the potential of fish waste hydrolysate (FWH) on enhancing phytoplankton production and reducing formulated feed in milkfish (Chanos chanos) culture. Milkfish fry (Average Body Weight (ABW): 0.137 ± 0.004 g) were randomly distributed in 27 Fiber Reinforced Plastic (FRP) tanks with 20 fry per tank. The experiment was conducted with three levels of FWH supplementation (0, 20 and 40 ppm) and three levels of feed supplementation (0, 50 and 100%). The FWH supplementation at 40 ppm significantly (p < 0.01) improved the average daily gain (ADG), total biomass gain and survival (%) of C. chanos. Further, the FWH supplementation at 40 ppm with 50% feed reduction showed similar ADG, specific growth rate (SGR), biomass gain in C. chanos compared with group received 100% feed without FWH. The FWH supplementation significantly (p < 0.01) increased the microalgae diversity and abundance compared to other treatments and has positive correlation with the enhanced growth performances of fish. The gut microbial study showed that 40 ppm of FWH significantly (p < 0.01) increased total bacterial load but inhibited Vibrio population. The FWH supplementation improved haematological parameters signifying better health status of C. chanos. Healthy histopathology of liver of C. chanos supplemented with FWH and fed with 50% feed also supported the effect of FWH on the enhancement of health status of C. chanos. It can be concluded that FWH supplementation at 40 ppm can save 50% of required feed without affecting growth performance and survival of C. chanos.

The Addition of Immunostimulant in Self-Formulated Feed to Improve Immunity and Growth of Juvenile Cobia (Rachycentron canadum)

The aims of the experiment were to determine optimum dietary immunostimulant level in self-formulated on nonspecific immune response and growth performance of juvenile cobia fish. Fish were kept in net cages (0.8 x 0.8 x 0.6 m 3 ) installed in fiberglass tanks which were completed with aeration and flow-through water system for 30 days. Design of the study was completely randomized design with 4 treatments, each consisting of 3 replications. Initial density was 50 fish for each replication with average body weight 4.69 g. the self-formulated feed (crude protein 46% and lipid 9%) containing three levels of immunostimulant additional levels, namely A (0.3%), B (0.5%), and as control, K (commercial feed as first control) and M (0.0% as second control without added immunostimulant. The data observed were growth performance which were consisted of absolute weight, total feed consumption, survival rate, specific growth rate, feed conversion rate and protein retention and mortality rate after challenge test with LD50 (1.0 x 10 9 CFU/ml) of pathogenic bacteria Vibrio alginolyticus. The growth performances showed that fish fed with addition of immunostimulant 0,3% (A) obtained higher absolute weight values and significantly different (p&lt;0,05) from M, but not significantly different from K. Challenge test at the end of the study showed that treatment A had lower mortality compared to other treatments which was indicated had higher immunity level compare to other treatments. Based on the results above, it can be concluded that the self-formulated feed with added immunostimulant 0.3% (0.7% total in the feed) showed the survival rate and optimal growth performance of juvenile cobia .

Hematological parameters, liver integrity and growth of Nile tilapia fingerlings fed diets supplemented with propolis extract

Aim of study: To assess the effects of propolis extract supplementation in diets for Nile tilapia (Oreochromis niloticus) fingerlings on growth performance, hematological and histological parameters. Area of study: The study was carried out in Paraná (Brazil). Material and methods: The experimental design was based on six treatments including the control diet and propolis supplementation (2%, 4%, 6%, 8% and 10% in the diet). Three hundred Nile tilapia fingerlings, with an initial weight of 0.61± 0.02 g, were distributed in 30 plastic mesh hapas (0.15 m3 each) arranged in a concrete tank of 25 m3 of water volume. The duration of the experimental period was 90 days. Main results: The increasing levels of propolis did not influence the growth performance and proximate composition of fishes. Red blood cells and hematological indices were not affected by propolis supplementation. However, total leukocytes and thrombocytes were higher in fish fed on propolis diets, being significant in fish fed 2% and 8%, and 6% and 8% supplemented diets groups, respectively. Research highlights: The supplementation of propolis alcoholic extract in the range of 2, 4, 6 and 8% in the diet for Nile tilapia fingerlings promote healthier fish with increased immunity in the evaluated culture conditions.

Effect of dietary fish oil replacement with grape seed oil on growth performance, feed utilization and fatty acid profile of mirror carp, Cyprinus carpio , fingerlings

This study aimed to investigate the effect of grape seed oil (GSO) on growth performance, feed utilization and the fatty acid profile of mirror carp fingerlings. Five isonitrogenous (36 g/100 g) and isoenergetic (3650 kcal/kg) diets supplemented with 0% (control), 0.5%, 1%, 2% and 3% of GSO were prepared. Three hundred fish (3.65 g) were randomly allocated in five trial groups in triplicate with 20 fish per aquarium and fed three times a day with experimental diets at satiation level for 84 days. Growth performance and feed utilization in fish were similar among all test groups, except for the GSO-0.5 group. The condition factor, feed intake, hepatosomatic index, viscerosomatic index and proximate composition were not affected by GSO inclusion levels, except fatty acid profiles in fish flesh. The highest Σn3-PUFA and Σn6-PUFA values were observed in the GSO-3 group, whereas this group showed the lowest atherogenic and thrombogenic index values compared with the other test groups. The ratio of hypocholesterolaemic/hypercholesterolaemic fatty acids in fish also increased by GSO inclusion levels. The results suggest that GSO supplementation up to 3% could improve fish flesh fatty acid profile and lipid quality without adverse effect on growth performance and feed utilization in mirror carp fingerlings.

Modulation of Muscle Growth Related Genes in Fish in Response to Plant Based Ingredients

Fish meal and fish oil have been the mostly used ingredients (protein and lipid respectively) in aquaculture feeds due to their excellent source of well-balanced amino acid profile and n-3 long chain polyunsaturated fatty acids (LC-PUFA) respectively. However, due to escalating prices and fluctuation in production, there are calls for alternative protein and lipid sources to be used. Plant based ingredients have been recognized as alternatives that could enhance growth performance as well as reduction in cost of production. The regulation of muscle growth by plant based lipids and protein is not fully elucidated. Growth performance and muscle growth of fish is affected by diets. Acceleration of growth through alteration of genes by diets can be useful as it can reduce cost and decrease time of production. The objective of this review is to discuss the genes that affect muscle growth of fish and how plant based ingredients affect these genes.

Functional Molecules of Intestinal Mucosal Products and Peptonesin Animal Nutrition and Health.

There is growing interest in the use of intestinal mucosal products and peptones (partial protein hydrolysates)to enhance the food intake, growth, development,and healthof animals. The mucosa of the small intestine consists of the epithelium, the lamina propria, and the muscularis mucosa. The diverse population of cells (epithelial, immune, endocrine, neuronal, vascular, and elastic cells) in the intestinal mucosa contains not only high-quality food protein (e.g., collagen) but also a wide array of low-, medium-, and high-molecular-weight functional molecules with enormous nutritional, physiological, and immunological importance. Available evidence shows that intestinal mucosal products and peptonesprovide functional substances, including growth factors, enzymes, hormones, large peptides, small peptides, antimicrobials, cytokines, bioamines, regulators of nutrient metabolism, unique amino acids (e.g., taurineand 4-hydroxyproline), and other bioactive substances (e.g., creatine and glutathione). Therefore, dietary supplementation with intestinalmucosal products and peptonescan cost-effectively improve feed intake, immunity, health (the intestine and the whole body), well-being, wound healing, growth performance, andfeed efficiency in livestock, poultry, fish, and crustaceans. In feeding practices, an inclusion level of an intestinal mucosal product or a mucosalpeptone productat up to 5% (as-fed basis) is appropriate in the diets of these animals, as well as companion and zoo animals.

Effects of ascorbic acid and iron nanoparticles supplements on hyperthermia-induced stress in African catfish, Clarias gariepinus (Burchell, 1822)

BackgroundThermal stressors in tropical aquaculture are unavoidable and cause many harmful effects. This study assessed the effects of ascorbic acid (AA) and iron nanoparticles supplementation in the diet of African catfish, Clarias gariepinus, and exposed to hyperthermia-induced stress. C. gariepinus juveniles weighing 6.89 ± 0.05 g were randomly distributed into plastic tanks of 48 cm by 30 cm by 31 cm dimension at ten fish per tank in a triplicate treatment. Five isonitrogenous and isocaloric diets containing 35% crude protein were formulated with AA and iron nanoparticles supplementation at (10, 8, 6, 4, 0) g/kg of AA and (0, 4, 6, 8, 0) g/kg of iron nanoparticles in treatment 1, 2, 3, 4 and 5, respectively. After 8 weeks of feeding, fish were exposed to hyperthermia-induced stress. Blood was collected from the fish for haematological and biochemical analyses.ResultsResults showed that there were significant differences (P < 0.05) in the growth performance and nutrient utilization of fish subjected to hyperthermia-induced stress. Treatment three had the highest specific growth rate of 1.89 g per day and the best feed conversion ratio (FCR) of 1.48.ConclusionMortality was reduced with the supplementation of the fish diets with AA and iron nanoparticles. Based on the result of this study, a supplementation level containing AA and iron nanoparticles supplementation of 6 g/kg and 4 g/kg were sufficient as a stress-reducing agent in the production of C. gariepinus during hyperthermia stress.

Valorisation of brown seaweed ( Sargassum wightii ) waste as a feed ingredient in rohu ( Labeo rohita ): Effects on growth and metabolism

A study was conducted to assess the role of supercritical-fluid-extracted-seaweed residue as a feed ingredient. 120 Labeo rohita fingerlings with an average weight of 1.83 ± 0.25 g were randomly distributed into four experimental groups and fed with diets containing seaweed waste as a dietary supplement at 0, 150, 250 and 350 g/kg of feed for a period of 60 days. The beneficial role was assessed in terms of growth-performance, metabolic, and defense mechanism. Animals fed with seaweed-waste showed significantly (p < .05) higher weight gain and specific growth rate (SGR). Activities of metabolic enzymes such as ALT, AST, LDH, MDH and SOD showed significantly (p < .05) lower activity in the animals fed with seaweed waste in the diet. The highest lysozyme activity was recorded in the animal's group fed with 250 g/kg of seaweed waste in the diet. Significantly, higher serum serotonin level was recorded in the animals fed with 250 g/kg of seaweed waste. It can be inferred, that the supplementation of seaweed waste as a fish feed ingredient at a 250 g/kg inclusion level improves the growth-performance, metabolic, and defense mechanisms in fish. Inclusion of seaweed waste as feed ingredients in the aqua-feed industry could possibly play an important role in reducing the cost of feed with added functional benefits.

Effect of different fish feeds on water quality and growth of crucian carp (Carassius carassius) in the presence and absence of prometryn

Few data are available regarding comprehensive or quantitative assessment of fish feed considering both the environmental and feeding impacts. Aiming to fill the gap, an experimental study to investigate the effects of three fish feeds on concentrations of nutrients and crucian carp (Carassius carassius) growth was conducted in laboratory aquariums in the presence and absence of prometryn. Results showed that weight gain rates of crucian carp treated with Tong Wei (TW) feed were 106.3% and 2.0% higher than that of Zhong Shan (ZS) and Zhong Liang (ZL) feeds, a possible explanation was that the quality of protein in TW feed was highest as evidenced by the protein efficiency ratios. Meanwhile, TW feed posed relatively lighter effects on water qualities (between ZL and ZS). Prometryn significantly inhibited the growth of crucian carp and thus affected concentrations of nutrients in water indirectly. The relationships between weight gain rates of fish and concentrations of nutrients in water (R2 = 0.929–0.990) were developed. In sum, this study suggested that it is realizable to obtain better fish growth performance with lesser degrading effects on water qualities by producing and selecting appropriate feed regardless of prometryn existence, and the developed equations could be used as a basis for future studies.

KOMBINASI SUHU DAN WAKTU KEJUT PANAS TERHADAP KEBERHASILAN TRIPLOID IKAN SEURUKAN (Osteochilus sp.)

The purpose of the research is to obtain the most desirable zygote age for the triploidization process using heat shock and to determine the growth performance of Seurukan fish breed as triploidized. The method used in this study is experimental method with a completely randomized design model, through 4 treatments, and 3 replications. P0: Normal spawning (control) P1: Temperature 42°C, zygote age 15 minutes old, temperature shock duration 2 minutes. P2: Temperature 42°C, zygote age 20 minutes old, temperature shock duration 2 minutes. P3: Temperature 42°C, zygote age 25 minutes old, temperature shock duration 2 minutes. The preferable hatching was found in P3 treatment with a zygote age of 25 minutes old and immersed duration for 2 minutes which was 91.27%. In addition, the highest survival rate was found in the control treatment which was 89.98% and the percentage of triploids successfulness was found in P2 with a zygote age of 20 minutes old and an immersed duration for 2 minutes which was 60%. The results present that the triploidization of Seurukan fish through a temperature shock of 42oC for 2 minutes at the zygote age of 20 minutes old after fertilization succeeded in inducing triploid fish. The optimum treatment that able to produce the highest triploid (60%) with a survival rate of 81.1% is a temperature shock of 42oC for 2 minutes at the zygote age of 20 minutes old after fertilization.

Selenium and Zinc Oxide Multinutrient Supplementation Enhanced Growth Performance in Zebra Fish by Modulating Oxidative Stress and Growth-Related Gene Expression.

Selenium and zinc are important dietary micronutrients having antimicrobial and antioxidant roles, thereby assisting in normal development, and an enhanced immune system. Supplementation of selenium and zinc for enhancing the growth performance and reproductive capacity in fish was explored in this study. Selenium nanoparticles (SeNPs) and zinc oxide nanoparticles (ZnONPs) were synthesized by high-energy ball milling (HEBM) using a 10-h dry milling technique at a 10:1 ball-to-powder ratio (BPR) and were premixed with basal feed followed by the administration to adult zebra fish (D. rerio) (2 months old) for 30 days. Growth analysis revealed that zebra fish fed with SeNPs + ZnONPs (2 mg/ kg, equimolar mixture) had significantly higher length and weight than only SeNP (2 mg/ kg) or ZnONP (2 mg/ kg) groups and control zebra fish (p < 0.05). The average length–weight relationships were assessed by estimating the condition factor (C), which was highest in the SeNP + ZnONP group (1.96), followed by a downward trend in SeNP (C = 1.15) and ZnONP (1.11) (p < 0.05). Relative gene expression of growth hormone and insulin-like growth factor-1 was significantly high in the SeNP + ZnONP group compared to other groups (p < 0.05), which indicated that combined administration of both the nanoparticles in basal feed enhanced the growth performance of zebra fish. Intracellular ROS generation was low in the combined group, followed by control, SeNP, and ZnONP groups, indicating higher concentrations of both nanoparticles, in particular, ZnONPs induced oxidative stress. Fecundity and the development of fertilized embryos were significantly high in the SeNP + ZnONP–treated zebra fish compared to only the SeNP- or ZnONP-treated group or control (p < 0.05). These findings indicated that supplementation of SeNP + ZnONP in basal feed could considerably improve the growth performance and development of zebra fish which could be exploited for enhancing aquaculture production.

In-Situ Biofloc Affects the Core Prokaryotes Community Composition in Gut and Enhances Growth of Nile Tilapia (Oreochromis niloticus)

Biofloc technology is commonly applied in intensive tilapia (Oreochromis niloticus) culture to maintain water quality, supply the fish with extra protein, and improve fish growth. However, the effect of dietary supplementation of processed biofloc on the gut prokaryotic (bacteria and archaea) community composition of tilapia is not well understood. In this study one recirculating aquaculture system was used to test how biofloc, including in-situ biofloc, dietary supplementation of ex-situ live or dead biofloc, influence fish gut prokaryotic community composition and growth performance in comparison to a biofloc-free control treatment. A core gut prokaryotic community was identified among all treatments by analyzing the temporal variations in gut prokaryotes. In-situ produced biofloc significantly increased the prokaryotic diversity in the gut by reducing the relative abundance of dominant Cetobacterium and increasing the relative abundance of potentially beneficial bacteria. The in-situ biofloc delivered a unique prokaryotic community in fish gut, while dietary supplementation of tilapias with 5% and 10% processed biofloc (live or dead) only changed the relative abundance of minor prokaryotic taxa outside the gut core microbiota. The modulatory effect of in-situ biofloc on tilapia gut microbiota was associated with the distinct microbial community in the biofloc water and undisturbed biofloc. The growth-promoting effect on tilapia was only detected in the in-situ biofloc treatment, while dietary supplementation of processed biofloc had no effect on fish growth performance as compared to the control treatment.

Transcriptome analysis provides insights into the molecular mechanism of hepatocyte apoptosis in response to feeding restriction in juvenile largemouth bass Micropterus salmoides

Feeding restriction (FR) is a scientific strategy to attenuate nutrient excess-mediated liver metabolic syndromes in human beings. However, it is still unclear whether liver health could benefit from FR in cultured animals including fish. In this regard, the regulatory role of FR in liver health of juvenile largemouth bass Micropterus salmoides were investigated in this study using single-molecule real-time sequencing and next-generation sequencing. Groups of fish (20 fish per group) with an initial body weight of 6.9 g were randomly allocated into 12 rectangular tanks (250 L each) operating as a recirculating aquaculture system. The satiation (ST) fish was fed to satiation, while ration levels of the moderately restricted (MR) and highly restricted (HR) fish were maintained at 85% and 70% of the ST fish, respectively. All fish were fed a commercial extruded diet containing 49.9% crude protein and 13.2% crude lipid. After a 9-week feeding trial, growth performance of the MR fish was not affected through improving the feed utilization as compared with the ST fish. Even though feed utilization was further improved, growth of the HR fish was still impaired. The MR fish obtained superior antioxidant status in the plasma and liver (based on glutathione or malondialdehyde concentration, and total antioxidant capacity and superoxide dismutase activities) together with better liver integrity (based on HE and TUNEL staining) than the other treatments. A total of 38,909 full-length transcripts were generated from the sequencing. GO enrichment analysis of the differentially expressed genes (DEGs) showed that many terms related to immunization and wound repair were enriched in the feed restricted fish (especially the MR fish). A total of 701 DEGs were identified in the liver of the MR fish as compared with the ST fish, and the apoptosis was enriched as the prominent pathway by KEGG pathway analysis. Our results suggested that the intrinsic apoptosis pathway played an important role in the hepatocyte apoptosis inhibition in the MR fish. Specifically, the activation of Akt might mediate an anti-apoptosis role through inhibiting the release of direct IAP binding protein with low pI (DIABLO) from mitochondria and promoting the transcription of pro-survival genes such as X-linked inhibitor-of-apoptosis protein (xiap), which coordinately activated the inhibitor of apoptosis protein (IAP). Besides the intrinsic apoptosis pathway, our results indicated that the lysosome pathway and endoplasmic reticulum stress pathway might also participate in regulating hepatocyte apoptosis inhibition of the MR fish.

Evaluation of oil-based inactivated vaccine against Aeromonas hydrophila administered to Labeo rohita, Cirrhinus mrigala and Ctenopharyngodon idella at different concentrations: Immune response, immersion challenge, growth performance and histopathology

The present study aimed at developing Montanide oil based inactivated vaccine against Aeromonas hydrophila and assessing immunogenic potential of two Indian major carps (Rohu: Labeo rohita and Mori: Cirrhinus mrigala), and a Chinese carp (Grass carp: Ctenopharyngodon idella) commercially cultured in Pakistan. Fishes were randomly distributed in three vaccinated groups with three vaccine concentrations at 108, 109 and 1010 colony forming unit (CFU)/mL and an unvaccinated control group. Fixed dose of 0.1 mL was intraperitoneally injected to each fish on 1st day and a booster dose at 15 days post-vaccination (DPV). Blood samples were collected at 14, 28, 35, 48 and 60 DPV to determine antibody titers in blood serum using complement fixation test (CFT). Growth parameters were also measured on fortnightly basis. The immune response showed highest antibody Geometric Mean Titers (GMT) on 35 DPV in all vaccinated groups which remained significantly higher than control group till 60 DPV. Fishes were challenged at 60 DPV with infectious A. hydrophila with 108 CFU/mL through immersion bath. The relative percentage survival (RPS) was 89% for fishes vaccinated with 109 and 1010 CFU/mL potencies while 78% for 108 CFU/mL potency. Vaccination did not cause adverse effect on growth performance of fishes. Minor degenerations, with non-significant histopathological changes were observed in few vaccinated fishes as compared to control group in which majority of the fishes presented deteriorative changes in tissues histology.