Lower Food Conversion Ratio Research Articles

Effect of copepod Apocyclops dengizicus addition on growth, survival, and proximate composition of Macrobrachium rosenbergii postlarvae cultured in brackish‐water biofloc system

AbstractObjectiveThe effects of periodically adding the cyclopoid copepod Apocyclops dengizicus (every 4 days at a rate of 4 individuals/mL) with biofloc technology (BFT‐C) was compared with conventional biofloc technology (BFT; without copepod) or a clear‐water control for Macrobrachium rosenbergii postlarvae nursery culture.MethodsSurvival, growth, proximate composition, and economics of SMacrobrachium rosenbergii postlarvae was calculated. Water quality and biofloc proximate composition were also measured among treatments. For the BFT, maize starch was applied to achieve a C:N ratio of 20:1. Triplicate 125‐L polyethylene tanks containing 500 postlarvae each (9.40 ± 1.88 mg) were evaluated.ResultSpecific growth rate was significantly greater in the BFT‐C group (8.40 ± 0.24% per day) than BFT (7.23 ± 0.21% per day) and control (7.12 ± 0.42% per day) groups. Postlarvae survival was significantly increased with the BFT‐C (94.46%) treatment compared with the BFT (87.33%) and control (82.60%). A significantly lower food conversion ratio (1.08) was obtained in BFT‐C than both the BFT (1.73) and control (1.90), possibly due to significantly higher biofloc crude protein and lipid contents in the BFT‐C than BFT. Postlarvae whole‐body protein and lipid contents were significantly elevated in BFT‐C compared to the BFT and control treatments. Economics of gross return, net return, and cost‐benefit ratio were significantly better at BFT‐C than in either the BFT or control groups.ConclusionThis study indicates that copepod additions with BFT enhanced prawn postlarvae survival, growth, and whole body protein and lipid, as well as economics, which could augment productivity and sustainability in this industry.

Performance of nursery Litopenaeus vannamei post-larvae in a BFT system enriched with Rhizoma coptidis broth

The shrimp farming industry has historically been limited by outbreaks of bacterial diseases. The current study aimed to investigate the performance of adding Rhizoma coptidis (R. coptidis), an herbal medicine, to the biofloc system of Litopenaeus vannamei culture. A broth of boiled R. coptidis was added to four experimental groups (C0 (control), C2, C4, and C6, with respective dry weights of 0, 2, 4, and 6 g/L R. coptidis). The results showed that the nitrase and dehydrogenase activities of the biofloc enriched with R. coptidis were enhanced compared to the control group. Shrimp reared in the systems enriched with R. coptidis showed significantly better growth performance, digestion, and immune enzyme activity and a lower food conversion ratio compared to the control group. The mortality rate for Groups C4 and C6 in a Vibrio infection test was less than 50 %, while Group C0 experienced 100 % mortality. There were no significant differences in ammonia or nitrite concentration among the treatment groups. These results suggested better performance of nursery Litopenaeus vannamei post-larvae in BFT systems by enrichment with 4 g/L R. coptidisL broth.

Natural Food Intake and Its Contribution to Tambaqui Growth in Fertilized and Unfertilized Ponds

Natural food available in ponds can complement formulated feed in fed aquaculture. This study elucidated the natural food intake and its contribution to tambaqui (Colossoma macropomum) growth in fertilized and unfertilized ponds, using stable isotope and stomach contents analyses. Additionally, it described the impact of fertilization management on natural food availability, fish performance, and production costs. Tambaqui juveniles (93.8 ± 15.0 g) were stocked (0.55 fish/m2) in fertilized (Fert) and unfertilized (NoFert) ponds (600 m2) for a culture period of 10 months in quadruplicate. A lower food conversion ratio was observed in Fert ponds. The main natural food items ingested by tambaqui were insects, vegetables, and cladocerans. Plankton contributed 39.4% and 10.7% of muscle formation in Fert and NoFert ponds, respectively. Pond fertilization (2.45 g of nitrogen and 0.80 g of phosphorus per square meter every two weeks) did not significantly affect fish growth, survival, or productivity but had a slightly influence on water quality parameters. However, fertilization increased the zooplankton density (through phytoplankton) in the water, thereby increasing autochthonous food availability for tambaqui consumption. This species demonstrates the ability to alternate between natural food sources and commercial feed without compromising its development. Consequently, tambaqui exhibits suitability for farming within restorative and integrated aquaculture systems as well as intensive systems reliant on commercial feed.

Valorized Palm Kernel Cake and Bambaranut Meal Affects Amino Acids, Growth and Nutrient Utilization in African Catfish, <i>Clarias gariepinus</i>

The high cost of fishmeal and plant protein like soybean has necessitated the search for alternative aqua feed ingredients like proteinous agro waste products. Agro waste are cheap and plausible alternative but lacks some essential amino acids and has several anti-nutritional factors (ANF) like phytic acid, non-starch polysaccharides, high fiber, and protease inhibitors. Solid-state fermentation of the agro wastes can reduce the ANF and improve the protein and nutritional values of feed ingredients. Palm kernel cake (PKC) is a byproduct of palm kernel oil production, and it is proteinous and abundant in Nigeria. Bambaranut meal (BNM) is a neglected proteinous legume high in methionine and lysine and is abundant and cheap. Freshly produced PKC and BNM were solid-state fermented for 5 days in a bioreactor using Saccharomyces cerevisiae and used to produce five novel diets. The inclusion levels of solid-state fermented PKC: BNM per diet were as follows: F1, 450:50, F2,350:150, F3,250:250, F4,150:350, and F5,50:450. There was a control diet labeled as feed F6 which was a control. A total of 270 African catfish fingerlings of average weights distributed as follows F1, 2.63±0.06g, F2, 2.70±0.13g, F3, 2.40±0.08g, F4, 2.30±0.05g and F5, 2.70±0.09g, were acclimatized for 7 days and stocked at 15 fish per 3 replicates aquaria per treatment feed. The catfish were fed ad libitum two times daily with the treatment feeds for 70 days. Culture water was changed daily. Catfish were weighed every 14 days. The catfish that received feed F4 (PKC:BNM;150:350g) had the best specific growth rate (SGR) of 4.43±0.06% day-1, lowest food conversion ratio (FCR) of 1.01±0.07 and highest protein efficiency ratio (PER) of 1.24. The catfish fed feed F3 (PKC: BNM) 250:250g, was next to F4 with SGR, Final weight, gut volume, and gut weight were all higher for catfish receiving feed F4 followed by those fed feed F2. There were no significant differences between the PER of catfish-fed diets F2, 0.39±0.03 and F3, 0.39±0.06. The lysine and methionine content of the feed increased with inclusion of FBNM than FPKC. In conclusion, solid state fermented BNM and PKC should be included in catfish feed for optimal growth and profitability.

Effect of dietary nutmeg (Myristica fragrans) on growth performance, antioxidant status, immune response, and gene expression of common carp (Cyprinus carpio)

The aim of this study was to assess the effects of dietary nutmeg (Myristica fragrans (MF)) on growth, innate immunity parameters of serum and mucus, antioxidant defence, and expression of immune genes in common carp (Cyprinus carpio). Three hundred fish (3.79 ± 0.02 g) in four groups were distributed in twelve glass aquariums with a capacity of 150-L. The groups were T1 or control (0% MF), T2 (0.5% MF), T3 (1% MF), and T4 (2% MF), and the fish were sampled after 42 days. According to the results, diet supplementation showed significantly higher weight gain (WG) and lower food conversion ratio (FCR). Final weight (FW) increased in groups fed 1% and 2% MF and specific growth rate (SGR) improved in those provided 1% MF (P < 0.05). Alternative complement activity (ACH50) and the total immunoglobulin (total Ig) level were found to be significantly higher in T4 and T3 groups, respectively than in the T1 (P < 0.05). However, lysozyme (LYZ) and total protein (TP) in all treatment groups showed no significant variation compared with the T1. Similarly, feeding fish with supplemented diets did not affect the antioxidant status and mucus immune parameters. Additionally, fish fed 1% MF showed a significantly higher intestinal catalase (CAT) and superoxide dismutase (SOD) gene expression (P < 0.05). However, LYZ expression significantly decreased in the fish fed MF (P < 0.05). The results of the present study revealed the addition of MF to the diet affects the expression of both antioxidant and immune genes in common carp.

Impacts of dietary zinc oxide nanoparticles on the growth and immunity of Nile tilapia could be ameliorated using Nigella sativa oil

BackgroundZinc nanoparticles are documented to be harmful to fish because their accumulation in fish bring about many irreversible changes in their health. Nigella sativa and its oil have been endorsed in aquaculture to improve fish health. MethodsTwo hundred seventy experimental fish (113 ± 5 g body weight) were divided into 6 groups G1–6; control fish fed a diet without any treatment (G1), 0.3% of NSO (G2), 0.5% of NSO (G3), ZnO NPs (40 mg/kg diet) (G4), 0.3% of NSO and ZnO NPs (40 mg/kg diet) (G5), 0.5% of NSO and ZnO NPs (40 mg/kg diet) (G6), the trial lasted for six weeks. ResultsGrowth performance was enhanced in fish received diets containing NSO, final weight (FW), weight gain (WG), daily weight gain (DWG), and relative growth rate (RGR) were significantly increased with lower food conversion ratios (FCR) compared to the control. The hepatic glutathione peroxidase (GPx), catalase (CAT), and metallothionein (MT) were increased in response to ZnO NPs stress and only 0.5% NSO supplementation could ameliorate such increment. The immune-related genes [interleukin1-beta (IL-1β), tumor necrosis factor-beta (TNF-β), transforming growth factor-beta 2 (TGF-β2) and C-type lysozyme] as well as growth-related gene [insulin-like growth factor 1 (IGF1)] in liver showed an upregulation in fish fed with NSO diets. Administration of ZnO NPs lowered the resistance of Oreochromis niloticus against bacterial infection with Aeromonas hydrophila and NSO could enhance the immunity in the highest tested concentration (0.5%) (G6). ConclusionsThe obtained results implied that NSO could enhance the oxidative and immune status of O. niloticus which could compensate ZnO NPs stress as well as experimental infection of a virulent strain of A. hydrophila. Our results revealed that NSO might increase fish growth and immunity only at a high dose (0.5%).

Enhancement of body coloration of sword-tail fish (Xiphophorus helleri): Plant-derived bio-resources could be converted into a potential dietary carotenoid supplement

The effects of natural plant-derived carotenoid sources on body coloration and growth performance of Sword-Tail Fish (Xiphophorus helleri) were investigated using four different dietary treatments; Commercial Feed (CF), China Rose Flower (CRF), Marigold Flower (MFF), and Carrot (CAF). CF was used as the control treatment without a natural source of carotenoids. The sources were mixed with feed (15 g/100 g) during the diet preparation. Fish were fed with four treatments twice a day for eight weeks, and then sampling was done weekly. A total of 96 fish were used for the experiment, and the mean initial weights were 3.314 g. MFF-treated fishes showed better growth performance in terms of mean weight, length and Specific Growth Rate (SGR), and carotenoid gain than the other treatments. The lowest Food Conversion Ratio (FCR) was also observed in the MFF-treated fish. The study suggested that marigold flower mixed feed could increase the body coloration and boost the growth performance of sword-tail fish and may be manufactured.

Growth performance of Pangasius sp. cultured at different stocking density in floating net cages in Bijuri coalmine pond of Anuppur district (M.P.) India

The study deal with the comparative growth performance of Pangasius sp. cultured at different stocking density in floating net cages in Bijuri Coalmine pond of Anuppur district (M.P.). The experiment was conducted in 05 replications at 03 stocking densities in 15 floating net cages of the size -3.65 x 3.65 x 5.48 m (L x W x D). The stocking densities were- T1 (2600 fish fingerling/cage), T2 (2800 fish/cage) and T3 (3000 fish/cage). During experiment of 60 days, the fingerlings of pangas (Pangasius hypophthalmus were fed on commercial floating pelleted feed given to fish @ 5 % of their body weight per day. The fishes were properly maintained for good health by regular feeding schedule and use of prophylactic measures and probiotics. The results indicated that the weight gain (NWG), specific growth rate (SGR), food conversion ratio (FCR) and gross conversion efficiency (GCE) were significantly different (p < 0.05) in all the treatments. Still, the significantly higher growth performance was observed in T1. In this treatment NWG, SGR and GCE were the highest 289.570c±0.928g, 1.698c±0.019 and 0.852c±0.00 respectively. The lowest FCR (1.174a±0.004) was also recorded in T1 compared to all other treatments. The net yield in 60 days was maximum in T3 (9.080/m3) and per cent increase in biomass was maximum (176.955%) in T1. The fish growth was maximum at 30-45 days of observation which corresponds with water temperature of 24.56±2.16 °C, pH-8.02±0.11 and dissolved oxygen 8.28±0.14 mg/l. The higher Ponderal index was noticed in T1 i.e. 2.403b±0.057 indicating wellness of fish. Through this study we can recommended that in above conditions 2600 fingerlings of Pangasius hypophthalmus stocked in each floating net cage gives maximum growth and per cent increase in fish yield.

Effects of polysaccharide-based silver and selenium nanoparticles on growth performance, biochemical parameters, and immune response of Cyprinus carpio

Avicennia marina mangrove leaves polysaccharide (AMLP) was used for the synthesis of polysaccharide-based selenium (AMLP-SeNPs) and silver nanoparticles (AMLP-AgNPs). The synthesized nanoparticles were further characterized by UV-Vis, DLS, FT-IR, X-ray diffraction, and HR-TEM analysis. A 60-day (8 weeks) feeding trial experiment was conducted to investigate the effects of AMLP, AMLP-SeNPs, and AMLP-AgNPs dietary supplementation on growth performance parameters, blood parameters, immunological and enzymatic profiles in Cyprinus carpio. The characterization results of AMLP-SeNPs and AMLP-AgNPs confirmed the formation of well-stabilized spherical nanoparticles with a mean particle size of 37.25 and 72.40 nm, respectively having a crystalline structure. The feeding experiment results demonstrated that 2 mg/kg of AMLP-SeNPs followed by 0.2 mg/kg of AMLP-AgNPs showed significantly (p ˂ 0.05) higher final weight, weight gain (WG), specific growth rate (SGR%), protein and lipid efficiency, and lower food conversion ratio as compared to other groups. The catalase, superoxidase dismutase, and glutathione peroxidase activity were significantly (p ˂ 0.05) higher in the group fed 2 mg/kg supplemented AMLP-SeNPs. Total protein and globulin contents were significantly (p ˂ 0.05) higher and albumin concentration was significantly lower in fish that received 2 mg/kg of AMLP- SeNPs as compared to control. A significant increase in serum HDL and decrease in LDL and MDA concentrations were observed in the group supplemented with 2 mg/kg of nano selenium. The body's crude lipid, protein, moisture, and ash were not significantly different from the control. The AMLP-SeNPs showed significantly (p ˂ 0.05) lower aspartate aminotransferase (AST), alanine aminotransferase (ALT), and higher alkaline phosphatase (ALP) activities compared to other test groups. The relative percentage survivability (RPS%) was higher in AMLP-SeNPs (84.6%) followed by AMLP-AgNPs (76.7%) after 8th weeks of supplementary diets as compared to control groups. Overall, the finding of these studies revealed that the inclusion of AMLP-SeNPs improved the growth performance and antioxidant defense system, enhance immune response, and provide resistance against Aeromonas hydrophila in Common carp.

EFFECTS OF FEED REDUCTION ON GROWTH PERFORMANCE, WATER QUALITY, AND HEMATOLOGY STATUS OF AFRICAN CATFISH, Clarias gariepinus REARED IN BIOFLOC POND SYSTEM

Biofloc technique is a method of fish culture using minimal water exchange and microbial aggregates formed within the culture media as fish supplementary feed. Biofloc as a protein source is currently not being considered part of the feeding dosage in catfish culture. This present work aimed to determine the effects of commercial feed reduction on growth performance, water quality, and hematology of catfish cultured in biofloc ponds. Fish with an average body weight of 7.53 ± 0.47 g were stocked in nine ponds with a stocking density of 100 fish/pond and reared for nine weeks. The experiment was arranged in a completely randomized design, with the following treatments: full feed + non-biofloc (C100) as control; 10% less feed + biofloc (B90); 20% less feed + biofloc (B80). As such, the total feed doses given daily per each treatment fish biomass were: 5% for C100, 4.5% for B90, and 4.0% for B80. Each treatment was arranged in triplicates. The results showed that all water quality parameters (dissolved oxygen, pH, TAN, and nitrite) and biofloc concentrations did not differ significantly among the treatments (P&gt;0.05). Specific growth rate, survival rate, weight gain, and feed conversion ratio of the fish were also not significantly different (P&gt;0.05). The weight gain of biofloc-treated fish in B90 and B80 reached 2.71% and 12.65%, respectively; which were higher than the control treatment during the treatment period. The feed conversion ratios of B90 and B80 were 14.39% and 7.58%, respectively; lower than the control treatment. The biofloc treatment did not adversely alter the fish’s blood cell profiles. This study revealed that feed reduction did not affect water quality in the ponds and blood cell profiles of the fish. Moreover, fish in the biofloc-treated ponds had higher weight gain and lower food conversion ratios compared to fish cultured in the non-treated biofloc ponds. This study suggests that using the biofloc system in catfish rearing can reduce the use of feed up to 10%-20% with similar biomass yield compared to the non-biofloc system.

Use of black soldier fly (Hermetia illucens) prepupae reared on organic waste as feed or as an ingredient in a pellet-feed formulation for Nile tilapia (Oreochromis niloticus).

The growth and sustainability of freshwater aquaculture are highly dependent on economic feed which is the major running cost. Fish feed industries depend on the high-priced fish meal (FM) as protein source in feed formulations. In this context, a nutrient-rich, and palatable insect meal-based fish feed was developed incorporating the black soldier fly (BSF) (Hermetia illucens) prepupae meal (BSFPM) reared on organic waste imparting additional benefit of waste bioremediation to make cost-effective feed. Feeding trial was conducted to evaluate growth performance on monosex Nile tilapia (Oreochromis niloticus). The different treatments were (1) dried BSF prepupae, (2) BSF prepupae and BSFPM-based feed in 1:1 proportion, (3) BSFPM feed, and (4) control feed with FM. The survival, growth, feed efficiency, and haematological parameters were not significantly different between BSFPM and control feed. Fish fed with control feed and BSFPM feed showed significantly higher (P ≤ 0.05) weight gain, specific growth rate, and percentage weight gain. Lowest food conversion ratio (P ≤ 0.05) was recorded for fish fed control feed with a significantly higher feed efficiency ratio (0.65d ± 0.034) and protein efficiency ratio (2.11a ± 0.063). The mean corpuscular volume of blood in fish fed BSF prepupae (128.5a ± 3.2) is significantly higher. The good growth of fish fed BSFPM feed may be attributed to the essential amino acids which are not limiting in feed. Absence of microbes and safe level heavy metals in BSFPM feed ensures safety of the ingredient. Hence, it can be used as a suitable protein source in feed formulations.

Evaluation of cages dimension to the growth of giant trevally Caranx ignobilis

Fish growth is one of the most target in aquaculture with right method of feeding, water quality and size of cages where they were held. In this study, a 70-day research was conducted to evaluate the effect of floating net cages dimension on growth and survival of trevally Caranx ignobilis in Ambon Inner Bay of Indonesia. A total of 90 juvenile trevallies with an average weight of 17.18 ± 1.9 g was randomly stocked in six floating net cages at three different sizes as treatments in replicate groups. Fish were fed 10% of total body mass with by catch fish twice a day to satiation. Length and weight were recorded, growth performance of fish were assessed in the form of Specific Growth Rate (SGR), Food Conversion Ratio (FCR) and Survival rate (SR). The result showed there were no significant different growth rate (SGR) at different treatments (p>0,05), with the highest SR = 100% and lowest FCR = 2.9 both in treatment C. It means the best dimension of fish rare in this research was at the biggest size of cage 200 × 150 × 100 cm 3.

Effect of dietary supplementation of essential oil of Pistacia atlantica on liver tissue, some blood parameters and performance of Oncorhynchus mykiss

Some herbs have a wide range of beneficial properties, including stimulating and strengthening the immune system, their use in fish farms improves growth. Sixty healthy rainbow trout were selected with 150 g weight. They were randomly divided into 2 groups of 30 each with 3 replications. The essential oil was added to the daily diet with 10 g / kg feed and after 3 months the fish were assayed and sampled. some blood parameters was performed. The results showed that the control group had lower food conversion ratio (p < 0.05). Also, consumption of essential oil at this dose had negative effect on liver function and liver enzymes significantly increased (p < 0.05). Total protein, albumin, and blood glucose were decreased and uric acid and creatinine were significantly increased (p < 0.05). The blood cells were significantly decreased. In the histological examination around the central veins of liver was severe degeneration. Evaluation of blood biochemical values showed that AST, ALT in the treatment group significantly increased and total protein and albumin in the treatment group decreased significantly (P <0.05). Uric acid was significantly higher in the treated fish than in the control group (P <0.05).oral administration of Pistacia atlantica essential oil at this dose is not recommended in rainbow trout and causes tissue damage.Until it is decided whether or not to consume or conditionally consume these essential oils and to increase the efficiency of production and productivity in the country by increasing the clinical and localization of the country in fish farms.

Impact of graded dietary protein on growth parameters of hybrid (Labeo rohita ♀ and Catla catla ♂) from Southern Punjab, Pakistan

| This study was conducted to analyze the impact of varying levels of plant based protein diets (15%, 20%, and 25% crude protein) prepared from cheaper plant proteins, to keep minimum use of fish meal, on growth performance, survival and production of hybrid fry (Labeo rohita ♀ x Catla catla♂). The hybrid fry of mean 1.05±0.08 g body weight and 4.36±0.40 cm mean length were acclimatized and transferred to 8 X 6 X 3 ft. hapas. Fry were fed with fish meal at the rate of 10 % of body weight during acclimatization period and experimental feed at the rate of 5 % of body weight up to the end of the 90 days experiment in duplicate at the fish farms facility. The growth performance of test fishes was observed at monthly interval and accordingly the fish feed was readjusted. During the study period, water quality parameters were maintained within safe limits for fish growth. Ten fish specimens from each treatment were randomly collected at the end of trial for growth parameters analysis. Different growth parameters, such as mean weight gain, mean length gain, specific growth rate, protein efficiency ratio, feed conversion ratio and production were determined. Results revealed maximum gains in T3 (25%) feed group as compared to T1 (15%) and T2 (20%) feed groups. The lowest food conversion ratio (FCR) was also noted in the T3 (25%) group showing best feed composition of T3 (25%) feed by the tested fish fry. ANOVA analysis showed highly significant (P0.05) was observed in SGR, FCR and PER values of the three treatment groups. Hence, a protein diet containing 25% dietary protein is not only cost-efficient, economical but also nutritional and wholesome for a fish’s health condition.

Effect of Dietary Inclusion of Citric Acid with Phytase as Supplement on Growth Responses of Rainbow Trout

Rainbow trout, a salmonid species has an economic importance worldwide and contributes to the indigenous food security. The present study was conducted in complete randomized design (CRD) to evaluate the dietary inclusion of citric acid with phytase as supplement on growth responses of rainbow trout. There were four treatments of diets with 0.5% citric acid (T1), 1% citric acid (T2), 1.5% citric acid (T3) and 0% control (T4) of citric acid incorporated with 1200FYT phytase as supplement. The treatments were replicated three times. Total harvest weight of fish in T3 (5720.2±105.6g) was significantly higher and different than T2 (4595.9±434.9g), T1 (4589.8±240.2g) and T4 (4567.5±217.3g). The highest daily growth rate was seen in treatment T3 (1.1±0.0) which was significantly different than T2 (0.9±0.0), T1 (0.9±0.0) and T4 (0.8±0.0). The highest specific growth rate was seen in the treatment T3 (0.8±0.01) which was significantly different than T1 (0.7±0.0), T2 (0.7±0.1) and T4 (0.7±0.0). The lowest food conversion ratio was seen in T3 (2.2±0.1) which was significantly different with T2 (2.6±0.1), T1 (2.7±0.1) and T4 (2.8±0.1). Similarly, the highest protein efficiency ratio was seen in treatment T3 (1.0±0.1) which was not significantly different with T2 (0.8±0.0) and T1 (0.8±0.1) but was significantly different than T4 (0.7±0.0). No significant changes were observed in water temperature, dissolve oxygen and pH under different treatments. The present findings demonstrated that dietary inclusion of citric acid with phytase as supplement enhance growth by reducing the pH in the gut which increases the phytate hydrolysis, kills the pathogens, decreases the rate of gastric emptying, improves mineralization and nutrient absorption.

Effects of dietary pH and acid source on growth and feed efficiency of the Nile Tilapia, Oreochromis niloticus fry

Two feeding trials were conducted to investigate the effects of dietary pH (pH 2.5, 3.7, 4.6, 5.7-control, pH 7.0, and pH 8.0) and dietary acid source (acetic acid, citric acid, hydrochloric acid and control-no acid) on growth rate and feed utilization efficiency of the Nile tilapia fry. In addition, attractability of the diets at different pH and dietary acid sources were determined. Results of the first feeding trial showed that the feed with pH adjusted to 4.6 resulted in significantly highest final average body weight (FABW), weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and most efficient food conversion ratio (FCR) in the Nile tilapia fry. Survival was 100% in diets with pH 3.7 up to 7.0; the diet with pH 2.5 exhibited significantly lowest survival followed by the pH 8.0 diet. In the second feeding trial, diets that contained hydrochloric, citric or acetic acids that were used to adjust the pH to the optimal 4.6 resulted in higher FABW, WG, SGR, and PER values but lower FCR values than did the control diet; these parameters were not significantly different among the dietary groups. This study demonstrated that the dietary pH promoted growth and efficiency in the Nile tilapia fry and that the three acids that were used were similar in their effects on growth and efficiency. Furthermore, it was demonstrated that either acidifying the diet to pH 4.6 by an inorganic acid such as HCl or the provision of a dietary acidifier such as citric acid or acetic acid could enhance growth, feed efficiency and survival of the Nile tilapia.

Growth and osmoregulatory response of Cyprinus carpio haematopterus (Amur carp) reared in inland saline water

A 90 days experiment was designed to assess the growth and osmoregulatory response of Cyprinus carpio haematopterus (Amur carp) in inland saline water of sub-humid and semi-arid/ arid zones of Haryana, India. Two hundred forty fingerlings (avg. wt. 3.48±0.272 g) were equally distributed in 4 treatment groups (salinities; control C, 0 ppt; T1, 5 ppt; T2, 10 ppt and T3, 15 ppt) with 3 replicates in 500 L tanks followed by complete randomized design (CRD). There were no significant differences observed in physico-chemical parameters of water among different treatments and found in optimum range throughout the experimental period. The parameters, viz. total alkalinity, hardness (total, calcium and magnesium) and concentration of ions were varying with the salinity and displayed increasing trend with increase in salinity. At the end of experiment, 100% survival was obtained upto 5 ppt whereas decreasing trend was found with increasing salinity (T2 and T3). There was highest% weight gain obtained in control group followed by T1, T2 and T3 groups. The highest specific growth rate (SGR) and protein efficiency ratio (PER) along with lowest food conversion ratio (FCR) was reported in control group followed by T1 and T2 groups, while lowest SGR, PER and highest FCR were reported in T3 group. Serum and water osmolality showed significant increasing trend with increasing salinity, while osmoregulatory capacity was decreasing with increase in salinity. Based on the findings, it is suggested that Amur carp can be cultured with 100% survival up to 5 ppt with slightly lower production rate.

EFFECT OF WATER QUALITY AND DIFFERENT MEALS ON GROWTH OF CATLA CATLA AND LABEO ROHITA

The human body cannot make significant required quantities of vital nutrients but fish is minimum-fat, big-protein nutrition that delivers a variety of health advantages. Several external factors including temperature, oxygen level, alkalinity and photoperiod have impact on growth rate while water is also an important parameter in fish rising. Therefore, there is need to work and evaluate impact of fish food and water quality to improve the fish growth. For this purpose, twelve glass aquaria (six with ground water and six with surface water) were considered to assess growth and food conversion ratio (FCR) of Catla Catla and Labeo Rohita and two feeds (i.e. sunflower and bone meal) were provided. The feed has been given twice a day and changed 4% on the rate of body weight of fingerlings in the ground water pond and surface water pond as well. The fingerlings get the most elevated body weight in ground water and on sunflower meal (1.43 ± 0.01 g) as compared to surface water and bone meal (1.39 ± 0.03 g). The general lengths obtained using the fish feed have gotten to be (5.78 ± 0.03cm) on sunflower meal and (5.47±0.03 cm) on the bone meal. The values of FCR had been lower (better) on sunflower meal (2.13±0.01) as compared to bone feast (2.32±0.03). In conclusion, it was observed from the results that fishes fed on sunflower meals had shown better growth with improved morphometric parameters and lower FCR values.

Effects of antioxidant supplementation (nano‑selenium, vitamin C and E) on growth performance, blood biochemistry, immune status and body composition of rainbow trout (Oncorhynchus mykiss) under sub-lethal ammonia exposure

This study aimed to investigate the protective effect of diets supplemented with different combinations of three antioxidants (nano‑selenium (NanoSe), vitamin C and E) on rainbow trout (Oncorhynchus mykiss) under sub-lethal concentration of ammonia exposure. For this goal, triplicate groups of 25 fish/tank (11.89 ± 0.34 g) were subjected to ammonia stress (0.024 mg/L) and fed with three experimental diets as T1 (0.1 mg/kg NanoSe, 100 mg/kg vitamin C and 30 mg/kg vitamin E), T2 (0.2 mg/kg NanoSe, 200 mg vitamin C and 60 mg/kg vitamin E), T3 (0.3 mg/kg NanoSe, 300 mg/kg vitamin C and 90 mg/kg vitamin E) and a basal diet as control, for 40 days. The obtained results showed that the fish fed with T2 and T3 diets had significantly higher final weight, weight gain, specific growth rate, protein efficiency ratio and lipid efficiency ratio, when compared to T1 and the control group. Also, all the supplemented diet treatments showed lower food conversion ratio, compared to the control group. Furthermore, while serum catalase showed meaningful decrease in T3 treatment only, all T1, T2 and T3 groups had decreased superoxide dismutase activity. Similarly, a significant decrease was observed in serum malondialdehyde in fish fed the supplemented diets. In addition, while serum total protein increased in T1 and then decreased in T2 and T3, triglyceride levels increased in T2 and T3 treatments. Furthermore, total immunoglobulin levels, serum lysozyme and albumin significantly increased in T2 and T3.. In terms of body crude protein, crude lipid, crude fiber, dry matter, ash and carbohydrates, we observed no significant changes. Totally, our results suggest that diets supplemented with NanoSe, vitamin C and vitamin E in T2 could increase growth performance, antioxidant capacity and immune responses in juvenile rainbow trout exposed to ammonia stress.

Effect of feeding stimulants on growth performance, feed intake and appetite regulation of mandarin fish,Siniperca chuatsi

Mandarin fish is a typical carnivorous fish, it can accept artificial diet after domestication, which is significantly essential to optimize its artificial diet. Nevertheless, only few studies were conducted on artificial diet of mandarin fish. Therefore, an 8‐week feeding trial was conducted to evaluate the influence of feeding stimulants on growth performance, feed intake and appetite regulation of mandarin fish. In this trial, six diets were formulated, a basal diet contained 80% of Fish Meal without feeding stimulants, named as Control, 0.4% inosinic acid meal, 0.4% L‐Alanine meal, 3% Yeast meal, 3% a commercial squid extract meal and 0.4% betaine meal were added into the basal diet to make five experimental diets, which were named as IM, AM, YM, SVO and BM respectively. At the end of feeding trial, SVO group showed higher feed intake, up‐regulated mRNA expression of neuropeptide Y (NPY) and down‐regulated mRNA expression of pro‐opiomelanocorticoid (POMC) significantly as compared to control group, which suggested that squid extract improved feed acceptability and promoted appetite in mandarin fish. Similarly, compared to control group, SVO group showed low food conversion ratio, high weight gain and SGR, indicated that squid extract enhanced the growth performance. Our results suggested that the appropriate level of squid extract addition could contribute to optimize artificial diet in mandarin fish.