Fry Weight Research Articles

АРАЛ ҚАЯЗЫНЫҢ (LUCIOBARBUS BRACHYCEPHALUS) ШАБАҚТАРЫН ҚОЛДАН ӨСІРУ ТӘЖІРИБЕСІ

This article presents the results of research to assess the growth of fingerlings of the rare and endangered Aral barbel (Luciobarbus brachycephalus) in fish farms in the Kyzylorda region. The research cover in detail the work on the cultivation of larvae in pond conditions obtained from individuals of barbel caught in the Syrdarya River in the territory of the Kyzylorda region. For research purposes, the characteristics of the pond and the water source in it are given, as well as a description of the tools for conducting control catches. The results of control catches of barbel larvae from the moment they were planted in the pond were analyzed to determine the growth rates of their main biological indicators. The deadlines and intervals of control work are also described in detail. In the conditions of the pond, the obtained results of analyses of indicators of the Fulton fatness index of barbel fry in comparison with representatives of barbel in their natural habitat are presented. During the results of growing barbel fingerlings, it was shown that the average weight of fry in the 2nd decade of September reached 15.1 g, and this indicator gives full opportunity to harvest fish planting material in the conditions of fish farms in the region.

Effect of stocking density on growth performance, survival and production of Monosex Tilapia (Oreochromis niloticus) under nursery ponds in northern regions of Bangladesh

The present study was to assess and evaluate the culture potential of Tengra with short-cycle species in the seasonal water bodies of farmers’ fields and disseminate the cultural technologies in a different part of the country. The research study was evaluating the improvement of nursery management technique in drought prone area of Northern region in farmer field level. Before conducting research fish farmers of Different upazila were selected by departmental authority and pre training management. Growth, survival and production performances of Oreochromis niloticus fingerlings were evaluated for 40 days in nine nursery ponds having an area of 20 decimal each with an average depth of 1.0 m. Three stocking densities such as 1000 dec-1 (T1=Treatment-1), 1200 dec-1 (T2= Treatment-2) and 1400 dec-1 (T3=Treatment-3) were tested with three replications. Fry were fed with commercial nursery feed (30% crude protein). The rate of feeding was 25% to 8% of the estimated body weight of fry. The physico-chemical and biological parameters of pond water were within the suitable range for fish culture. Growth in terms of final weight, final length, weight gain, length gain and specific growth rate was significantly higher in T1 than those obtained from T2 and T3. The survival of fish fingerlings was higher in T1(85.67%) than T3 (76%) and T2 (83%) respectively. Maximum of fingerlings was produced in T2 than those in T1 and T3. Among the treatments evaluated, 1000 dec-1 was the best stocking density considering the growth performance of the fingerlings of monosex Tilapia, O. niloticus in nursery ponds.

The regulatory effects of water probiotic supplementation on the blood physiology, reproductive performance, and its related genes in Red Tilapia (Oreochromis niloticus X O. mossambicus)

Probiotics are becoming increasingly popular as eco-friendly alternatives in aquaculture. However, there is limited research on their impacts on the reproductive efficiency of Red Tilapia (Oreochromis niloticus x O. mossambicus) broodstock. Therefore, this experiment aimed to explore the combined effects of selective probiotics Bacillus subtilis and B. licheniformis (BSL; 1:1) added to water on blood hematology, serum metabolites, gonadal histology, reproductive performance, and reproductive associated genes in Red Tilapia broodstock. Tilapia broodfish weighing 140–160 g were stocked in four treatment groups: control (T0), and the other three groups were added different levels of BSL to the water as follows: T1 (0.01 g/m3), T2 (0.02 g/m3), and T3 (0.03 g/m3), respectively. Results indicate that BSL administration significantly improved RBCs, hemoglobin, hematocrit, MCH, and MCHC, with the highest improvement seen in the T3 group (P < 0.05). BSL added to the fish water significantly enhanced serum protein fractions (total protein, albumin, and globulins), while AST, ALT, ALP, creatinine, uric acid, and glucose were significantly diminished in a dose-dependent way (P < 0.05). Adding 0.02–0.03 g/ m3 of BSL resulted in higher antioxidant status (superoxide dismutase and catalase) compared to other groups (P < 0.05). Testosterone levels were higher in T3 than in other groups (P < 0.05). All female hormones (LH, FSH, estradiol, and progesterone) were substantially augmented by the addition of BSL. Additionally, the BSL groups exhibited higher GSI, HSI, VSI (male only), egg diameter (mm), mean number of fry/fish, and mean fry weight (g) compared to the control group (P < 0.05). Expression of reproductive-associated genes (vasa, nanos1a, nanos2, dnd1, pum1, AMH, and vtg) were significantly up-regulated in the gonads of fish in the 0.03 g/m3 treatment. The histological gonadal structure exhibited that BSL improved gonad maturation in both genders of Tilapia fish. Overall, adding a mixture of B. subtilis and B. licheniformis (0.03 g/m3 water) can accelerate reproductive performance in Red Tilapia through up-regulation of reproductive genes and enhance the health profile.

Потенціал росту стерляді прісноводної (Acipenser ruthenus Linnaeus, 1758) в ювенальний період за використання пробіотичного препарату «Емпробіо»

Purpose. To study the effect of the complex probiotic “Emprobio” on the survival and growth rates of larvae and fry of the sterlet (Acipenser ruthenus) as well as to assess its effect on the morphological structure of the intestine and liver. Methodology. The study of the effect of the probiotic was carried out on larvae and fry of sterlet. 6-hour enrichment of live feed organisms was carried out in 2 variants. In the variant 1, the concentration of the probiotic preparation was 0.4 cm3/dm3 of the incubation mixture. In the variant 2, similarly, the preparation concentration was 4.0 cm3/dm3. Larvae and fry were fed with Artemia nauplii, which were the transfer of the probiotic. Every 7 days, the average fish weight, the growth and survival rates were analyzed. Determination of the number of colonies of lactic acid bacteria in the intestines of fish was carried out by the method of deep seeding in Petri dishes. Determination of unicellular fungi was carried out by the method of serial dilutions of intestinal contents in a peptone-buffer solution with subsequent inoculation on a sterile wort-agar medium. Light-optical examination of cells and tissues was carried out in penetrating light using the equipment “E. Leitz “diaplan” Wetzlan” (Germany), halogen illuminator “Linvatec-2” (USA). General morphometric studies of tissue structures were performed with the help of a built-in eyepiece-micrometer as well as with the use of an eyepiece-micrometer overlay grid (eyepiece 7x (Huygens). In-depth studies of individual tissue areas were carried out using a 100x objective, “I-Plan” with a built-in iris diaphragm of 5.5 units of a compensation 20x eyepiece “K. Zeiss”. The data were statistically processed in MS Excel. Findings. During the 1st 7 days of the experiment, there were no significant differences in the growth rate of larvae between the groups.In the 2nd week of the experiment, an increase in the average daily weight gain of fish was observed in the experimental groups, which exceeded the control by 47.0% and 24.7%, respectively.At the end of the experiment, the average weight of fry of the 1st group was higher by 26.9%, and of the 2nd — by 27.9%, compared to the control group. As a result of the use of the probiotic preparation for 28 days, the survival rate of sterlet juveniles in the 1st experimental group was 75.0%. That is, it was 47.1% higher than the results of the control group. In the 2nd experimental group, the survival rate of sterlet juveniles was 80.1%, which was 6.8% higher than in the 1st group, and 57.1% higher than in the control group. The use of “Emprobio” in the feed at a concentration of 4.0 cm3/dm3 contributed to a faster process of microflora redistribution in the intestine. Therefore, already after the 1st 5 days of exogenous feeding, the average daily growth rates of the juveniles in this experimental group had higher values (by 8.8%) compared to the control group. The results of inoculation the intestine contents in the experimental groups showed that the use of the probiotic preparation in the incubation mixture in the amount of 0.4 cm3/dm3 ensured the inoculation of probiotic lactic acid bacteria in the intestines of sterlet juveniles. Their functioning was reflected in fish productive parameters, starting from the 14th day of the experiment. However, the lack of intestinal inoculation by one of the components of the preparation, namely saccharomycetes, indicated the insufficiency of such a concentration to show the full potential of the probiotic. In the 2nd experimental group, positive growth dynamics of the entire microbiome can be seen. Histological studies showed a positive effect of the probiotic preparation at a concentration of 4.0 cm3/dm3 on the morphological structure of the liver. In particular, the area of hepatocytes, which increased by 42.9% after 7 days of the experiment and by 63.0% after 21 days of the experiment. The sizes of the nuclei and the ratio of the diameter of the nucleolus/nucleus of hepatocytes also increased. At the same time, the probiotic did not cause probable changes in the morphological structure of the intestinal wall. Originality. For the first time, the possibility of using the complex probiotic “Emprobio”, introduced by enrichment in live feed for growing sterlet in the juvenile period was analyzed.A positive effect of probiotics at a concentration of 4.0 cm3/dm3 on growth processes and survival of starlet juveniles was shown. The effect of microorganisms on the histostructure of the intestine and liver of the sterlet was clarified. Practical value. The obtained results will be useful for improving the technology of growing sturgeon larvae and fry. Keywords: sterlet, growth rate, survival, enrichment, probiotic, Emprobio, intestine, liver.

The addition of papaya leaf powder (Carica papaya L.) in feed to increase digestibility of milkfish fry (Chanos chanos)

The purpose of this study was to see the effect of adding papaya leaf powder with different doses to increase the growth rate and digestibility of milkfish fry (Chanos chanos). The method in this study used a completely randomized design (RAL) with 4 treatments each with 5 repetitions. The treatment used in this study was feed without the addition of papaya leaf powder or control treatment (A), the addition of papaya leaf powder 2% (B), 2.5% (C) and 3% (D). The feed that has been made is added with chromium which functions as an indicator of digestibility. Feeding is carried out for 40 days. The results showed that the addition of papaya leaf powder had a significant effect (P&lt;0.05) on increasing the specific growth rate, growth in absolute length and absolute weight, FCR and digestibility of milkfish fry, but had no significant effect (P&gt;0.05) on survival rate (SR). The best results in this study were shown in treatment D (with the addition of 3%/kg papaya leaf powder to the feed) showed a specific growth rate 0.93%, absolute length and absolute weight growth respectively 1.12 cm and 0.37 g, FCR 1.86%, and digestibility were 77.7%.

Dietary mannan-oligosaccharides enhance hematological and biochemical parameters, reproductive physiology, and gene expression of hybrid red tilapia (Oreochromis niloticus x O. mossambicus)

This study was carried out to evaluate the effects of dietary supplementation of mannan-oligosaccharides (MOS) on physiological performance, reproduction capacity and gene expression of hybrid red tilapia (Oreochromis. niloticus x O. mossambicus) broodstock reared in concrete tanks (3.5 × 3.2 × 0.9 m). Four isonitrogenous (30% cp), isocaloric (18.72 MJ kg−1) diets containing 0.0, 0.5, 1.0 and 1.5 g kg‐1 MOS were prepared. The diets were fed to triplicate groups of red tilapias broodfish (155 ± 5.65 g) stocked at a male: female ratio of 1:3, to satiation twice a day for two months. At the termination of the feeding trial, fish in each tank were netted and weighed. Blood samples were collected from five fish per tank to determine the hematological and biochemical parameters. The fish were then dissected for assessing the reproductive performance and its related genes. The results indicate that the values of hematological parameters (RBCs, Hb, and Htc) total protein, albumin, globulin, and reproductive hormones (testosterone, follicle-stimulating hormone and luteinizing hormone) were significantly increased by MOS dietary inclusion (1.0–1.5 g kg-1), while liver function enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were significantly decreased in fish fed with 1.5 g /kg of MOS (p < 0.05). Reproductive performances, including GSI, total number of fries per female and mean fry weight were significantly improved with increasing dietary MOS to 1.5 g kg−1. Gonads maturation was also enhanced with supplemental MOS to 1.5 g kg−1. In males, the highest testosterone concentration was recorded at 1.5 g MOS kg−1 diet. In females, FSH and LH were significantly increased with increasing MOS levels up to 1.0 g kg−1, and then leveled off. Conversely, the highest E2 and Prog concentration was obtained at 1.5 g kg−1. The expression of CYP19a, FSHR, FOXL2, CYP1A, ESR1, and ESR2A were significantly upregulated in the gonads of fish fed diets treated with MOS, up to a concentration of 1.5 g kg-1. These results suggest that a dietary supplementation of MOS (1.5 g kg−1) could enhance the reproductive performance of red tilapia.

Combined effect of temperature, salinity and dissolved oxygen on the survival of Nile tilapia (Oreochromis niloticus) fry during transportation, at different densities and durations

The transport of live fish is a delicate aquaculture operation that is carried out to distribute the fry or juveniles produced in the laboratories, to the culture farms. In the present work, survival after transport, survival during the subsequent 8 days (8-D PTS), and blood glucose as an indicator of stress, were determined in a simulated transport of Oreochromis niloticus tilapia fry of two sizes (1.2 ± 0.3 g and 2.4 ± 0.3 g), to find the best transport conditions. A total of 63 treatments per size, were tested combining three transport times (4, 8, and 24 h), three densities (54, 66, and 80 g/L), three temperatures (20, 22, and 24 °C), three salinities (3, 6, and 9 ‰) and three concentrations of dissolved oxygen (DO) (10, 15, and 20 mg/L). The tests were carried out in 2 L plastic bags, containing 0.5 L of water and an atmosphere above of pure oxygen. In general terms, the tested conditions of temperature, salinity, DO and density did not produce fry mortality at the end of transport in any of the treatments. However, the 8-D PTS gradually declined during the first 4–5 days and stabilized up to day 8 of experimentation. Survival of small fry of 1.2 ± 0.3 g was significantly (P < 0.05) lower (77.7 ± 10.4%) compared to that (94.2 ± 6.1%) obtained in 2.4 ± 0.3 g fry. The expected 8-D PTS was plotted as response surfaces to show 8-D survival as a function of density, transport time, and fry weight. Mortality during the 8-day post-transport period was the result of the combined effect of temperature and handling of the fry, rather than due to a lack of oxygen or ammonia concentrations since both variables were at tolerable levels for the species. With these results, it is concluded that the best transport conditions, under the evaluated scenarios, are obtained with fry of 2.4 ± 0.3 g transported at a density of 80 g/L for up to 24 h, at 24 °C and 3 ‰.

Potensi Pakan X Terhadap Pertumbuhan Benih Ikan Lele (Clarias batrachus ) dalam Pelestarian Sumber Daya Alam Hewani

Catfish is a leading commodity for the people of Indonesia because it is easy to cultivate and nutritious. The purpose of this study was to determine the potential of feed X on the growth of catfish fry. This study used an experimental laboratory method. The research design used RAL with 3 replications. The stages of the research included qualitative and quantitative measurements of the content of carbohydrates, fats, proteins, and measuring the weight of catfish fry every week for 1 month. The results of the qualitative test showed that feed X was positive for carbohydrates, fat and protein. Quantitative test results for carbohydrates, fats and proteins on feed X were: 84.72%; 0.60g ; and 0.12%. The results of measuring the weight of catfish seeds for 1 month showed an increase from week to week. The conclusion of this study is that feeding X can increase the weight growth of catfish fry so that it is very potential for the preservation of animal resources

Pemanfaatan Kubis sebagai Bahan Pakan Buatan untuk Pertumbuhan Benih Ikan Lele Mutiara (Clarias gariepinus)

Pearl catfish has the main advantage of fast growth. To maximize this growth, one of the things that must be considered is the feed given. The use of factory feed for catfish seeds is common, so it is necessary to use feed raw materials that are around to be used as raw materials for homemade feed. Vegetable waste such as cabbage and tofu dregs can be used as fish feed which is processed into pellets. Cabbage vegetable waste, tofu dregs, bamboo shoots and bran have protein and carbohydrates that can be used for fish growth. This study consisted of 2 stages, namely stage 1 analyzing the comparison between factory feed and homemade feed and stage 2 analyzing the difference in dosage of homemade feed on the growth and efficiency of pearl catfish (C. gariepinus) seed feed. Data were analyzed using 2 independent samples (unpaired) t-test and ANOVA test. The results showed that the provision of factory feed and homemade feed did not have a significant effect on the growth of length, weight, and feed efficiency of catfish fry. Catfish seeds can be fed homemade feed with ingredients from fermented cabbage waste, tofu dregs flour, rebon flour, bran flour, plus vitamins and minerals. The results of the analysis of variance in the treatment of different feed doses (4%, 5%, 6%, 7%, and 10% per fish body weight), had a significant effect on the growth of catfish length and weight, and had no significant effect on feed efficiency. The higher the dose given for the maintenance period of 30 days of catfish fry gave a good effect with the best dose of 10% per fish body weight

Small scale shrimp (Litopenaeus vannamei) nursery technology at high stocking density

One of the potential management measures to improve shrimp production is by the application of progressive system of vannamei shrimp cultivation, which is applied by many cultivators by spreading fingerlings. The advantage is that the fry has a high level of vitality and is adapted to the pond environment, which can be used by compensators to catch up during the rearing process, and shorten the rearing time in the enlargement phase. However, the need for a high number of fries, especially in the intensive and super-intensive technology, requires a nursery technique with the principle of high stand density and narrow volume. This research examines the vannamei shrimp nursery technology at high density. The container used was a 20 m3 volume round fiber tank, equipped with aeration, scattered with PL-10 vannamei shrimp at a stocking density of about 5,000 - 20,000 PL/m3, and maintained for 21 days. The results have an average vannamei fry weight of 0.26 ± 0.11 g / ind, a survival rate of 97.63 ± 1.93%, a feed conversion ratio of 0.52 ± 0.13, and a productivity of 3.20 ± 1.03 kg / m3. The average production cost of vannamei fingerling was IDR. 61.1 ± 6.56 per individu with the highest profit rate of IDR. 6,419,294 obtained at a stocking density of 20,000 PL/m3 per production cycle.

Larval rearing of fringe‐lipped carp,Labeo fimbriatus(Bloch) with low cost diets including green bottle flyLucilia sericata(Meigen) larvae meal incorporated diet

A study was conducted with non-conventional ingredients to test their efficacy as fishmeal (FM) replacers in the diet of fringe- lipped carp. Labeo fimbriatus first feeding larvae and fry were reared for 30 and 60 days in indoor, 50 L, aerated, circular plastic tanks at 100 and 30 numbers tank−1, respectively. In the first feeding larvae to fry rearing experiment (Exp. 1), the fish were fed with either of the following isonitrogenous and isocaloric diets – live plankton, FM diet, green bottle fly (Lucilia sericata) larvae meal (GBFLM) diet and silkworm pupa (SWP) diet. The fry to fingerling rearing (Exp. 2), was also conducted using the same diets described above except live plankton. All compounded diets were formulated to contain 40% crude protein for the experiment 1 and 35% for experiment 2 and were fed ad libitum. Triplicate tanks were maintained for each treatment in both the experiments. In Exp. 1, the mean final weight of fry was higher with plankton and FM diets, while no difference (p > .05) was observed between FM and GBFLM diets. Weight of fish fed SWP diets was not statistically different from those fed GBFLM diet. No difference (p > .05) in final length, survival and condition factor was recorded. Analysis of digestive enzyme activity of whole fish revealed lower (p < .05) activity of amylase in fish fed plankton. In Exp. 2, no difference (p > .05) was observed between the different diet groups in terms of mean final weight, length, survival and condition factor. Analysis of digestive enzyme activity of whole fish revealed no difference (p > .05) in the activity of digestive enzymes between the treatments except a lower (p < .05) activity of trypsin in FM diet and lipase in FM and GBFLM diets. Since the survival and condition factors of animals is the most important aspect during nursery rearing, similar (p > .05) values recorded in different treatments indicate the possibility of incorporation of these non-conventional protein sources in the diet of L. fimbriatus during first feeding larvae to fry and fry to fingerling rearing.

Effects of Light Intensity and Photoperiod on the Growth Performance of Largemouth Bass (Micropterus salmoides) in Recirculating Aquaculture Systems

HighlightsLight design is needed in recirculating aquaculture systems.A long photoperiod is beneficial to largemouth bass growth.Low light intensity is beneficial to largemouth bass growth.Abstract. In this study, recirculating aquaculture systems (RAS) were used to culture juvenile largemouth bass, and the effects of LED light intensity and photoperiod on the survival and growth performance of juvenile largemouth bass were studied. In the light intensity experiment, largemouth bass juveniles with an initial weight of 0.53 ±0.02 g were subjected to a two-month feeding experiment under two different light intensities: group A, at 0.5 W m-2 in the first month and 5 W m-2 in the second month; and group B, at 5 W m-2 in the first month and 0.5 W m-2 in the second month. The results showed that in the first month of the experiment, the growth rate of fry was faster in group A than in group B. After changing the light intensity, the weight of the fry in group B after one month of growth had exceeded and was significantly higher than that in group A. Based on the above experimental results, we conducted a photoperiod experiment. Largemouth bass juveniles with an initial weight of 0.56 ±0.02 g were cultured for two months under four different photoperiods (24L:0D, 16L:8D, 8L:16D, and 0L:24D). The light intensity of the four groups was 0.5 W m-2. The fry growth rate was fastest in the 24L:0D photoperiod group and slowest in the 0L:24D photoperiod group. The growth rate of the 24L:0D photoperiod group was significantly higher than that of the 0L:24D photoperiod group (p &amp;lt; 0.05). The final fry weight was highest in the 24L:0D group, followed by that in the 16L:8D group and 8L:16D group, with the lowest weight observed in the 0L:24D group (p &amp;lt; 0.05). Although the different light conditions in the two experiments had no significant effect on the survival rate of juvenile largemouth bass (p &amp;gt; 0.05), a low-intensity light environment with a continuous photoperiod during the juvenile largemouth bass culture process promoted growth and development. Keywords: Growth, Largemouth bass, Light intensity, Photoperiod, RAS.

Features of rainbow trout farming technology in PE “Zakhidna Rybna Kompania”, for feeding with Aguafeed Fischfutteer

The production of trout products in ponds and aquaculture farms is based on modern and long-term plans for technology and intensification of production, through the introduction of the latest approaches, by borrowing the experience of leading foreign producers, expanding production areas and sectoral investments. The main indicator that characterizes the efficiency of fisheries and reflects the state of production and the level of its economic indicators. is fish productivity Growing trout in aquaculture in a closed water supply is associated with high planting densities per unit area, the use of high-protein granular feed, which must fully meet the needs of fish in all necessary nutrients to ensure a balanced diet. In modern farms for feeding trout use high-protein feed mixtures in the form of grits and pellets. The dynamics of the intensity of growth and development of rainbow trout mainly depends on the location of the farm, the quality of the water supply source, the feeding regime of fish and the quality of feed. Therefore, the aim of the work was based on a review of literature sources and analysis of economic activity of the studied farm to give a general description of trout feed, Aquafeed Fischfutter, used for fish feeding, and determine their effectiveness, taking into account geographical location and abiotic and biotic factors . In addition, the study fish performance when feeding these feeds. Conduct research on the growth rate of rainbow trout, changes in weight and length of larvae, fry, yearlings and commercial fish, in tray, pool and pond cultivation. Develop a scheme for growing all age groups of trout on these feeds. Establish indicators of quality, nutritional value, feed ratio of starting, growth and production feeds. To give an objective assessment of their impact on the growth of larvae, fry, yearlings and commercial rainbow trout in the conditions of trout farming PE “Zakhidna Rybna Kompania”, Perimyshlyany district, Lviv region. The conducted research gives the basis to claim that this compound feed guarantees high daily gain. Being a high-energy feed, its use does not lead to obesity of fish. With intensive feeding, a good ratio of price and productivity of farmed fish is realized. The risk of contamination of water bodies and fish is very low, due to the low phosphorus content and good digestibility of feed – 1.1 kg of feed/kg of fish growth. The feed corresponds to the best world indicators in accordance with buoyancy and stability in water.

Effects on the Growth and Digestive Enzyme Activity in Nile Tilapia Fry (Oreochromis niloticus) by Lead Exposure

Lead is a metal capable of affecting physiology and metabolism in fish, including Nile tilapia (Oreochromis niloticus). However, few studies have evaluated the effects of lead on digestive enzyme activities in fry. At that stage, independent feeding begins, and there is increased demand and consumption of food, so chronic exposure to metal during this stage of development would cause null or minimal growth in organisms. In this study, fry from Nile tilapia was used to evaluate the effects of lead acetate by chronic exposure on the growth and the activities of the digestive enzymes after 30 and 60 days exposures. Four treatment groups 0.025, 0.050, 0.075 and 0.100 mg/L of lead acetate and a lead-free control were established. The activity of enzymes decreased, in the case of acidic proteases after 30 days and lipases after 60 days of exposure, from 0.025 and 0.050 mg/L of lead acetate, respectively. The amylase activity increased in metal-treated, while the chymotrypsin decreased partially at 60 days. Lipases decreasing activity might be causing an increase of triglycerides (lipids) and body mass observed during the first 30 days of exposure. Concentrations, equal to or above 0.075 mg Pb/L, cause significant effects on size and weight of fry, with nearly 54% lower than controls. At chronic exposure and early stage of development, the enzymatic activity is partially reduced along with body weight gain, which would affect subsequent growing and aquaculture production. The digestive enzyme response is discussed as a possible limited biomarker of exposure, to be used in biomonitoring.

Bio-physiological characteristics for juvenile coho salmon Oncorhynchus kisutch of artifcial and natural origin

Results of biological and physiological surveys of juvenile coho salmon from hatcheries of Magadan Region (artifcial origin) and from the main rivers of the northern Okhotsk Sea coast (natural origin) are presented. Biological and morpho-physiological indices of coho fry are compared between different salmon hatcheries and different rivers. Hematological indices for the fsh of natural origin are considered in dynamics. Positive effect of the higher water temperature and longer growing in artifcial conditions on length, body weight, fatness, feeding intensity and morpho-physiological indices of internal organs (liver, intestines) is detected for the coho fry; effect of the water temperature on length and weight of coho salmon in natural conditions is also positive. There is concluded that the coho salmon growing from the larvae under relatively high and stable temperature (4–5 oC) can provide the weight of fry over 0.6 g no later than middle July. If coho salmon is cultivated in conditions of low temperature (0.8–1.0 оС), the short-term growing before release (2.0–2.5 months) under a higher temperature (&gt; 5o) is recommended to improve its fry quality, possibly in the nursery ponds equipped in natural reservoirs — in this case, the juveniles with the weight over 1.0 g could be produced in late August. Hematological indices are measured for different age groups of coho salmon from several rivers. Their dependence on the water temperature was not determined because of high variety of physiological state. However, a signifcant deviation to decrease from the normal values was detected for the red cell count and hemoglobin content in blood of the coho juveniles caught from the Taui River in 2018, obviously reasoned by their younger age and lower size and weight. The juveniles caught from the Yana River in 2016 had no signifcant deviations from the normal values, except of the hematocrit value that indicated stable conditions of their habitat and normal age structure. The hematological indices (hemoglobin content and red cell count) of coho juveniles caught from the Taui River in 2013 and 2014 corresponded to the end of downstream migration. Increasing of hematological indices with age of juveniles is found for coho salmon of natural origin living in favorable environments (favorable water temperature, good food supply).

Comparative Study on Growth and Survival Rate of Oreochromis niloticus (Linnaeus 1758) Treating with Supplementary Feed at Different Feeding Regime

This experiment was designed with three experimental treatments namely T1 (natural feed), T2 (feeding with 10% body weight) and T3 (feeding with 5% body weight) for ten weeks. In the content of 33.8% of crude protein (CP), 11.2% of crude fiber (CF), 6% of fat and 10.2% of ash content feed were used as an experimental diet in this experiment. The stocking densities were 280 fish decimal-1 in three treatments where the mean initial weight of fry was 20 ± 0.2 g in all treatments combined and at the end of the experiment the mean final weight was found as 58.9 ± 2.86 g, 134.4 ± 3.62 g and 142.5 ± 4.23 g for T1, T2, and T3 respectively. Mean initial length was 10.2 ± 0.01 cm in three treatments and final length was found as 14.58 ± 1.60 cm, 18.74 ± 1.23 cm and 20.16 ± 2.08 cm in T1, T2 and T3 respectively. The mean weight gains 38.9 ± 1.53 g, 114.4 ± 3.05 g and 122.5 ± 1.5 g, mean length gain 4.38 ± 0.24 cm, 8.54 ± 0.65 cm and 9.96 ± 0.59 cm, mean SGR 1.76%, 3.5% and 3.82% were recorded in T1, T2 and T3, respectively. The highest weight gain, length gain and SGR were found in T3 and the lowest was found in T1. The survival rate was 82%, 88% and 94% in T1, T2 and T3, respectively. FCR values were found as 3.49 ± 0.5 and 2.51 ± 0.4 in T2 and T3. The result demonstrated that feeding with 5% body weight had a better effect on the growth and survival rate of monosex (male) O. niloticus.

Generation of Myostatin Gene-Edited Channel Catfish (Ictalurus punctatus) via Zygote Injection of CRISPR/Cas9 System

The myostatin (MSTN) gene is important because of its role in regulation of skeletal muscle growth in all vertebrates. In this study, CRISPR/Cas9 was utilized to successfully target the channel catfish, Ictalurus punctatus, muscle suppressor gene MSTN. CRISPR/Cas9 induced high rates (88–100%) of mutagenesis in the target protein-encoding sites of MSTN. MSTN-edited fry had more muscle cells (p < 0.001) than controls, and the mean body weight of gene-edited fry increased by 29.7%. The nucleic acid alignment of the mutated sequences against the wild-type sequence revealed multiple insertions and deletions. These results demonstrate that CRISPR/Cas9 is a highly efficient tool for editing the channel catfish genome, and opens ways for facilitating channel catfish genetic enhancement and functional genomics. This approach may produce growth-enhanced channel catfish and increase productivity.

Genetic variation and correlated changes in reproductive performance of a red tilapia line selected for improved growth over three generations

The present study examines genetic variation and correlated changes in reproductive performance traits in a red tilapia (Oreochromis spp.) population selected over three generations for improved growth. A total of 328 breeding females (offspring of 111 sires and 118 dams) had measurements of body weight prior to spawning (WBS), number of fry at hatching (NFH), total fry weight (TFW) and number of dead fry (NDF) or mortality of fry including unhatched eggs at hatching (MFH). Restricted maximum likelihood (REML) analysis in a multi-trait model showed that there are heritable genetic components for all traits studied. The heritability for WBS was very high (0.80). The estimates for traits related to fecundity (NFH, TFW) and survival (NDF) were low and they were associated with high standard errors. Genetic correlations of WBS with other reproductive performance traits (NFH, TFW and NDF) were generally positive. However, NFH was negatively correlated genetically with TFW. As expected, body measurements during growth stage exhibited strong positive genetic correlations with WBS. The genetic correlations between body traits and reproductive performance (NFH, TFW, NDF) were not significant. Correlated responses in reproductive traits were measured as changes in least squares means between generations or spawning years. Except for WBS that increased with the selection programs, the phenotypic changes in other reproductive traits observed were not statistically significant (P>0.05). It is concluded that the selection program for red tilapia has resulted in very little changes in reproductive performance of the animals after three generations. However, periodic monitoring of genetic changes in fecundity and fitness related traits such as NDF or MFH should be made in selective breeding programs for red tilapia.

Cage Culture of Carps in Ox-Bow Lakes of Assam: A Case Study

A demonstrative cage culture of commercially important fish species was carried out at Gelabeel in Golaghat District and Moridikhow beel in Sivasagar District of upper Assam during 2013-14 as a technology for enhancement of fish production as well as an alternative source of livelihood for the rural people. Five carp species viz., Labeo rohita, L, calbasu, L. gonius, Catla catla and Cirrhinus mrigala were taken as candidate species for 3 months trial culture. Rice bran and mustard oil cake blended in 1:1 ratio was given in pelleted form daily @3-5% of aggregate body weight of fry. Percentage of fish recovery from a 2m3 after 90 days was 71.67 in first trial and 86.67 in second trials. The average growth increment for about 3 months was 114.8mm and 131.6g and the average growth increment per month was 38.26mm and 43.86g. On an average, a profit of Rs 840/- per cage was recorded in 3 months. At Moridikhow also, all the species showed encouraging growth However, poaching is a major problem and community participation for development of cage culture has been suggested.

Effect of Use Fresh Macro Algae (Seaweed) Ulva fasciata and Enteromorpha flaxusa With or Without Artificial Feed on Growth Performance and Feed Utilization of Rabbitfish (Siganus rivulatus) fry

This study a low-cost aquaculture diet with fresh seaweed was tested with the herbivorous rabbitfish (Siganus rivulatus) fry. Two fresh seaweed was genera, Ulva and Enteromorpha (belong to family Ulvaceae) were used to replace the artificial feed by 0, 50 and 100 percent regardless the protein percentage. Initial average weight of fry was 0.18 g. This trial consisted of sixth treatments, the first treatment (T1) fish fed on artificial feed only, the (T2) fish fed of half feeding rate on artificial feed and other fresh Ulva , the (T3) fish fed of half feeding rate on artificial feed and other fresh Enteromorph, the (T4) fish fed on fresh Ulva only, the (T5) fish fed on fresh Enteromorpha only and the (T6) fish fed of half feeding rate on fresh Ulva and other fresh Enteromorph. Feeding rat was 7% of biomass and this trial continued for 70 days. There were significant differences between the treatments in all the growth performance parameters. The T3 was the highest in final weight (W2), total weight gain (TG), average daily gain (ADG), relative growth rate (RGR) and specific growth rate (SGR), followed by both the T2 and T1. And the best feed conversion ratio (FCR) was achieved with T3, T1 and T2 followed by T6 and T5 but the T4 had the worst FCR.