Survival Of Fry Research Articles

Effect of dietary enhanced Moina macrocopa (Straus, 1820) on the growth, survival and nutritional profiles of hybrid Nile tilapia fry

The cladocera Moina macrocopa serves as a common live feed that is suitable for most freshwater fish species. Seven diets for the cladocera, viz. Chlorella sp., rice bran, soybean meal, chicken manure, swiftlet waste, canola oil, and artificial micro pellet were compared in this study. This study's objective was to analyse the effect of enriched M. macrocopa on the growth, survival, and dietary profiles of hybrid Nile tilapia fry. The feeding experiment lasted for over 60 days. The M. macrocopa enriched with rice bran has produced the highest weight gain (5.83 g), survival (86.67%), protein (24.88%), and lipid (6.85%) in Nile tilapia fry. While, fatty acid such as α-linolenic acid (ALA; 4.67%) was found to be the highest in fry fed with M. macrocopa enriched with soybean meal. Arachidonic acid (ARA; 3.69%) and docosahexaenoic acid (DHA; 0.47%) were the highest in tilapia fry fed with M. macrocopa enriched with rice bran, while eicosapentaenoic acid (EPA; 6.33%) was the highest in tilapia fry fed with M. macrocopa enriched with Chlorella sp. In conclusion, the manipulation of nutrient such as protein, lipid and fatty acid Scompositions in M. macrocopa diet has successfully improved the nutrient compositions and production of Moina sp. culture that indirectly increased the growth and survival of hybrid tilapia fry.

Preferences for rohu fish (L. rohita) traits of women and men from farming households in Bangladesh and India

As selective breeding programs are time-consuming and expensive, it is critical that clients preferred traits are accurately identified. This is important to achieve value for money and adoption of selectively improved fish, and an essential foundation for effective contributions of genetic improvements to farming system. Data on fish trait preferences of smallholder farmers are rare; when these do exist, there is no information on whether the preferences of men and women are similar or not. The present work reports the first gender-disaggregated study of trait preferences of men and women from farming households for rohu carp (L. rohita) in Bangladesh (288 respondents) and India (270 respondents), addressing a major segment of aquaculture production in south Asia. The paper generates a nuanced, novel, and comparative understanding of the preferred characteristics through a survey of smallholder farmers that: 1) uses open-ended questions relating to producer and consumer perspectives; and, 2) applies a stated choice experiment using 1000minds software to address trade-offs in choices between traits for a subset of (58–38) respondents. General preferences derived from expressed likes or dislikes emphasized the importance of good taste, characteristics indicating freshness and safety such as aspects of appearance and color, as expected for a perishable product, and of value for money, including size of fish or relative flesh quantity. The overall pattern of preferences were similar for men and women, but there were differences in that men focused more on economic-related characteristics and women more on characteristics associated with nutritional value and food safety. When producers identified what to improve, they focused on larger size fish, reduced culture period, fry survival and disease resistance. When choosing between traits in pair-wise comparison exercises, ranking of traits was similar for both men and women in both Bangladesh and India. Significant differences were only observed between genders for the lower ranked traits in Bangladesh. Larger size fish as a charateristic ranked first in all groups, but there were marked differences between the importance of price and taste in the two countries. Methodologically, the study demonstrated that general preferences, do not automatically translate into characteristics for improvement by breeding programs, and the latter were not necessarily an accurate guide to the preferences expressed when specific tradeoffs were considered. These findings emphasize the need for well-designed and targeted surveys to be able to accurately define trait preferences, in particular to identify the relative values of heritable traits for practical application in breeding programs.

Age‐Structured Interactions among Reintroduced Sockeye Salmon, Resident Kokanee, Invasive Mysids, and their Zooplankton Prey in Skaha Lake, British Columbia

AbstractIn 2004, after an 85+ year absence, Sockeye Salmon Oncorhynchus nerka were reintroduced into Skaha Lake, British Columbia. Prior to this, the lake’s planktivore community was dominated by kokanee (lacustrine Sockeye Salmon) and an invasive freshwater shrimp Mysis diluviana, and British Columbia fisheries managers were concerned that reintroduced Sockeye Salmon fry might reduce the abundance of zooplankton prey and negatively affect the abundance and size of kokanee available for the recreational fishery. We looked for possible adverse effects by introducing contrasting densities (0–2,309 fish/ha) of marked, hatchery‐origin Sockeye Salmon fry to Skaha Lake over 12 years (2005–2017). During each year, we monitored state change indicators of lake flushing, water temperature, nutrients, phytoplankton, microzooplankton, M. diluviana, kokanee, and Sockeye Salmon. Zooplankton consumption by Sockeye Salmon, kokanee, and M. diluviana was estimated via bioenergetics models. We found that (1) average densities of pelagic fish gradually increased above premanipulation densities and (2) survival (egg to winter) of kokanee fry was variable but positively associated with increased abundances of Sockeye Salmon fry. Average survival of age‐0 to age‐3+ kokanee in Skaha Lake exhibited no significant trends. We also found that (3) growth rates for age‐0 Sockeye Salmon fry and kokanee were stable during 2005–2013, despite moderate increases in fish abundance, but declined in 2017. This decline was associated with record‐high biomasses of kokanee and M. diluviana, record rates of zooplankton loss from predation and lake flushing, and reduced zooplankton production. We found that (4) bioenergetics data showed that, on average, 1.8% of annual zooplankton prey consumption was attributable to hatchery‐origin Sockeye Salmon fry, 2.8% to Lake Whitefish Coregonus clupeaformis, 13.9% to older kokanee, and 79.6% of the zooplankton was consumed by M. diluviana. We concluded that during 2005–2015 consumption by planktivores never exceeded production by zooplankton, but in 2017, when lake flushing rates were exceptionally high, consumption by planktivores exceeded lake‐carrying capacity for pelagic fish. Sockeye Salmon fry played virtually no part in these events.

Light spectra influence the reproductive performance and expression of immune and anti-oxidative defense genes in endangered golden mahseer (Tor putitora) female brooders

Present study was aimed to assess the effects of different light spectra on reproductive performance and mRNA expression of some immune and anti-oxidant defense genes in endangered golden mahseer. The relative fecundity of brooders and fertilization rate of eggs did not change due to different light spectra. Whereas there was significantly higher rate of hatching (%) of eggs and survival (%) of fry obtained from brooders reared in white and green light compared to blue light. No significant effect of light spectra was observed on the expression levels of il1β, il10, tlr5, and inos. There was a linear increase in the relative expression of serum amyloid A (saa) (Y = 1.980x – 0.118, R2 = 0.972) and igl (Y = 1.077x + 0.093, R2 = 0.998) from white light to green light with maximum values found under green light. The mhc1 level was higher in white and green lights compared to blue spectra. A positive linear correlation was noticed between mRNA expression of crfb4 and hatching percentage (Y = 13.95x + 69.07, R2 = 0.920) of the eggs as well as survival percentage of fry (Y = 0.054x – 3.520, R2 = 0.985) obtained from brooders under different light spectra. The expression levels of all three anti-oxidative defense genes were significantly and similarly affected by light spectra. The maximum expression of anti-oxidative genes was registered in white light, and the minimum was observed in blue light. Overall, the results suggested a higher reproductive performance and immune status of golden mahseer female brooders reared under green light. Hence, green lights could be a better option for broodstock management of golden mahseer in captive conditions.

Fry Survival Rate as a Predictive Marker of Optimal Production of Silver Carp (Hypophthalmichthys molitrix, Valenciennes 1844): A Biostatistical Study in Deroua Fish Farm, Morocco

Several indicators show that the world population is rapidly increasing with prospects of reaching close to 10 billion people in 2050. Optimal production of fish is a tentative goal to ensure human feeding and resources sustainability. The present study was performed on eggs of the silver carp, collected during the breeding season of consecutive years with different environmental temperature profiles at the Deroua Fisheries Station to evaluate the seasonal and inter-seasonal changes of eggs quality in order to promote a predictive marker for optimal production of silver carp. The viability of the obtained eggs was detected using ANOVA followed by the Tukey test to analyze fertilization rate, embryos survival rate, and fry survival rate. Data analysis showed no significant difference in the fertilization and survival rate of the embryos during the two breeding seasons, and therefore these can not be used as an adequate criterion to predict the viability of the fry of silver carp. Although the survival rate of the fry did not change during the first season, it changed significantly during the second when there was an increase in the environmental temperature. This factor could be responsible for the disturbance of the females' oogenesis and consequently the degradation of the eggs' quality. The results showed that the fry survival rate could be used as a parameter to predict the yield of silver carp production rather than the success of fertilization and the survival of embryos. This paper discusses the importance and scope of this approach.

The Effects of Vitamins C and E on the Growth Performance of Guppy (Poecilia reticulata Peters, 1860) Fry [*

This study was carried out to find the effects of water-soluble vitamin C and fat-soluble vitamin E on the growth of both guppies, Poecilia reticulata (Peters, 1860), a kind of live-bearing species. The control feed did not contain vitamins C and E, while the other 15 experimental feeds were prepared by changing the amount of starch, without altering the chemical structure, and adding vitamin C (100, 500, 1000 mg/kg) and vitamin E (75, 150, 300 mg/kg) in various levels. At the end of the trial had an ascending amount of both vitamin C and E in the diet and resulted with an increase in the developmental parameters in the offspring of guppies (p<0.05). In addition after a three month trial the group 16 of guppies had reached maturity, and juvenile. According to the results of this study, there is an increase in growth and survival of fry as the amount of vitamin C and E added in feed increases.

Bahasa Indonesia

Ornamental fish is a potential commodity because it has its own charm. One of the ornamental fish that currently has a lot of interest is Cupang fish (Betta sp.). Cupang fish at the seed stage really need good and quality feed to support success during cultivation. The purpose of this study was to analyze the effect of different natural feeds on the growth and survival of Cupang fish fry (Betta sp.) and to determine the best type of natural food for Cupang fish survival and growth. This study used a completely randomized design (RAL) with 3 treatments and 3 replications. Parameters observed were absolute weight growth, absolute length growth, specific growth rate, and survival rate. The results showed that different natural feeds had a significant effect on absolute weight growth, absolute length growth, and specific growth rates, while different natural feeds had no significant effect on Cupang seed survival. Furthermore, giving silkworms (Tubifex sp.) is the best natural food compared to water fleas (Moina sp.) and mosquito larvae (Culex sp.,) for the growth of Cupang fish seeds during maintenance.

Effect of stocking density on growth, feed utilization and survival of an endangered Tor khudree fry in floating cages in a tropical reservoir

Effect of stocking density on growth, feed utilization and survival of an endangered Tor khudree fry in floating cages in a tropical reservoir

Protocol development for the improved hatchery propagation of Tiger grouper Epinephelus fuscoguttatus (Forsskål, 1775) in Palawan, Philippines

The expanding grouper cage farming in Palawan, Philippines requires stable seed supplies from hatcheries to sustain the demands of fish cage operators. To improve the current hatchery practices for Tiger grouper Epinephelus fuscoguttatus (Forsskål, 1775), four experiments were undertaken. The first experiment (E1), involving three different temperatures ranges (T1: 24-26°C; T2: 27-29°C; and T3: 30-32°C) revealed significantly higher hatching rates at 27-32°C. The second experiment (E2) found that survival rates after 38 days from hatching were inversely proportional with density (T1: 3; T2: 5; and T3: 10 larvae L-1). The third experiment (E3) found that the growth and survival of fry raised at three different stocking densities for three weeks (from 21 to 42 days after hatching) were not significantly different. The fourth experiment (E4) compared the growth and survival of fingerlings (from 70–91 days after hatching) fed with two brands of commercial feeds. After three weeks, both treatments had comparable total lengths. These desirable results are attributed to the weekly thinning or reduction in the density of juveniles in E3 and E4 and the use of small rearing containers.

Assessing the impacts of in-feed probiotic on the growth performance and health condition of pangasius (Pangasianodon hypophthalmus) in a farm trial

The effects of in-feed probiotics on growth performance, haematological parameters, gut microbial content, and morphological changes to pangasius fish were assessed. The trial had three phases, i.e., larvae to fry (20 days), fry to fingerlings (45 days), and grow-out phase from fingerlings to marketing (90 days). The stocking densities were 400 m–3, 200 m–3, and 12 m–3 for phases 1, 2, and 3, respectively. Phases 1 and 2 were conducted in hapas in the same pond, whereas phase 3 was performed in concrete tanks. The in-feed probiotic was administered at a rate of 0.2 g kg–1 of feed three times per day in phases 1 and 2 only. In phase 3, in-feed probiotics was not applied to any groups. The treated group exhibited higher growth performances (p < 0.05) than the control in all three phases of experiment. The survival % in phase 1 and 2 were found significantly (p < 0.05) higher in treatment groups. This indicates that pangasius nurserers would benefit from using probiotics as a safeguard to increase fry survival to a greater extent. Two haematological parameters including red blood cells (RBC) and white blood cells (WBC) levels were found significantly (p < 0.05) higher in treated groups in phase 2 and 3, while glucose and hemoglobin level were found significantly (p < 0.05) higher in the treated groups during phases 2 and 3, respectively. The gut microbiota content was relatively higher in the treated groups in phase 2 and 3. Histological findings indicate that the use of probiotics during the nursing phases of pangasius induced a positive change in the intestinal morphological structures. The positive impacts of probiotics on the phase 3 confirmed an immediate and long-term growth performance and health of pangasius.

Evaluating the Potential for Rearing Walleye in Lined Ponds Filled with Well Water

Walleye (Sander vitreus) fingerlings (30 to 35 mm) are commonly reared in ponds filled with surface (i.e., lake) water, but the use of ground (i.e., well) water would provide increased biosecurity. We assessed the potential for using well water to rear walleye by comparing plankton and water quality over 30 days between organically fertilized lined ponds that were filled with either unfiltered lake or well water. All ponds were inoculated with plankton that originated from Blue Dog Lake, filled by May 15, 2020, and remained fishless. Zooplankton density and body size were consistently reduced in well ponds suggesting that fry survival and growth would be reduced. Initially, well ponds exhibited higher ammonia-nitrogen and alkalinity, but lower pH owing to the inherent chemistry of the well water. Later, reduced ammonia-nitrogen combined with increased dissolved oxygen and pH suggest that decomposition of the organic fertilizer occurred slower in well ponds. A phytoplankton bloom was successfully initiated but was difficult to maintain despite consistently lower zooplankton density in well ponds. While the use of well water would enhance biosecurity, these data suggest that walleye fingerling production would be reduced relative to lined ponds filled with productive, lake water. Increasing organic fertilizer, supplementing with liquid 28N:0P:0K, and/or filling ponds earlier (e.g., 30 days) may provide a more favorable environment for walleye culture in lined ponds filled with well water.

The Dietary Chitosan Positively Modulates the Growth and Survival of Barbonymus gonionotus Fry

The dietary chitosan has been largely used in the supplemental diets of terrestrial animals to improve growth and development. However, there is little information on the roles of dietary chitosan in growth and development of aquatic animals like fishes. Thus, this study aimed at determining the effects of dietary chitosan on growth performances and survival of Barbonymus gonionotus fry. A total of 600 B. gonionotus fry (2.12±0.02 g) were considered for this study. This experiment consisted of four treatments (0, 1, 2 and 3 g Kg-1 formulated feeds) and each treatment had three replications with a stocking density of 50 fry/tank. The dietary chitosan was supplied as 8% of body weight of each fry twice daily for 60 days. Fish fry treated with the dietary chitosan exhibited significant (P &lt; 0.05) improvement in growth (body weight gain, % body weight gain, specific growth rate, and feed conversion ratio) and survival of B. gonionotus in comparison with untreated control. The water quality parameters, such as temperature, pH and dissolved oxygen showed no significant variations, and maintained suitable range throughout the study period for fish growth. Among the treatments, application of 1 g chitosan kg-1 feed showed the highest positive effects on growth and survival of B. gonionotus fry, indicating their potentials for practical application in promoting sustainable aquaculture.&#x0D; Ann. Bangladesh Agric. (2020) 24(1) : 41-50

Influence of water mineralization and dissolved main cations on survival, size and seismosensory characteristics of perch fry (Perca fluviatilis L.)

Within two months the growing of the perch fry Perca fluviatilis L. carried out in the aquarium experiment. Fertilized eggs of this fish species were taken from the spawning ground of a small and unpolluted natural reservoir and placed in laboratory conditions for subsequent incubation under different hydrochemical conditions. Experimental groups of perch were created in two replicates that developed under control conditions with a water salinity of 160 mg/l, under conditions of fresh water diluted to 100 mg/l, and under conditions with water whose salinity was increased relative to the control to 400 mg/l in three different ways - by adding calcium, magnesium or sodium chloride salts. Temperature, light, and oxygen conditions for growing fry in all groups were the same. The perch larvae were fed first with small natural zooplankton, then with artificially grown nauplia of Artemia; perch fry - with tubificid from vermiculture. The average survival rates of late larvae and early fry of perch in the second half of the experiment were maximal in the groups that developed under hydrochemical conditions with the addition of Na+ and Mg2+ (73% and 67%), and minimal in the groups that developed in the least mineralized water (46%). At the end of the experiment, the surviving fry from the groups affected by the increased content of sodium chloride had statistically significantly (p &lt; 0.05) larger linear sizes than the fry from the control groups and groups that developed in the least mineralized water. Perch fry from the groups affected by increased concentrations of Ca2+ were characterized by a statistically significant (p &lt; 0.05) smaller number of pores in the infraorbital and mandibular seismosensory canals of the head, compared with fry formed in conditions of least water mineralization and the minimal content of this main cation in it. Thus, salinity values and features of the ionic composition of fresh water can significantly affect the development of perch fry, which should be taken into account when breeding it in aquaculture.

Potential role of L-ascorbic acid with Field cricket (Gryllus bimaculatus) meal in diets of Nile Tilapia (Oreochromis niloticus) during sex reversal and nursing

A synthetic androgen 17-α methyltestosterone (MT) commonly used in the production of mono-sex fry of Nile tilapia (Oreochromis niloticus) during the first 21 days for sex reversal has been considered to suppress immunity thereby reduce survival. Present trial was conducted to evaluate whether vitamin C (L-ascorbic acid, AA) supplementation would benefit in terms of survival, growth, and stress resistance. Nile tilapia fry were fed with isonitrogenous (57.8±0.2% CP) diets formulated using Field cricket (Gryllus bimaculatus) meal (approx. 79%) and fish meal (approx. 20%) to use as control, and five other diets were prepared by supplementing 10, 20, 30 40 and 50 g of vitamin C (L-ascorbic acid per kg diet). Eighteen aquaria or glass tanks (100 L) were used having three replicates per treatment. Each aquarium was stocked with 300 fish (0.01±0.00 g). Fry were nursed for another 91 days to check their sex-ratio. Gonad histology showed increased number of spermatogonia when L-ascorbic dose was 30g/kg diet. At the end of the feeding trial results indicated significant increase (P&lt;0.05) in growth, feed utilization and survival when fed with vitamin C at the dose of 10 g/kg diet during sex-reversal and nursing periods as compared to the control. Similarly, hematological information also showed 10 g vitamin C dose per kg diet. Polynomial regression showed that the optimum dietary ascorbic acid doses were calculated at 15.9, 10.0 and 12.0 g AA per kg diet for highest survival (83.5% max), weight gain and SGR, respectively, but the doses higher than 20 g of L-ascorbic acid/kg diet was not beneficial. Highest apparent digestibility (AD%) of protein (84.1%) was at 15.37g and AD% of lipid (91.4% max) was 17.8g of vitamin C/kg diet. Salinity challenge test also showed highest survival can be achieved at 15.8 g AA per kg diet. As the survival of fry is the most important parameter at these stages, the dose which resulted highest survival i.e., 15 g/kg diet is recommended.

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.

Effects of Kigelia africana, Beta vulgaris and Ricinodendron heudelotti as feed additive on growth performance, survival and whole-body composition of Nile tilapia (Oreochromis niloticus) Linnaeus, 1758) fry

The effect of three African medicinal herbs used as feed additive on the growth and survival of Nile tilapia (Oreochromis niloticus) was studied. Four isoproteins (32%) and isolipid (13%) diets, namely RC (control diet or 0% plant), 3% B. vulgaris, 3% K. africana and 3% R. heudelotti, were manufactured. One hundred and eighty (180) Nile tilapia fry with an initial average weight of 0.15 ± 0.01 g were randomly distributed in 12 plastic tanks (50 L / tank) at a density of 15 fish per tank and fed three times (8.00 h am, 1.00 h pm and 5.00 h pm) per day for 90 days. For the parameters studied (average weight gain (AWG), feed conversion ratio (FCR), specific growth rate (SGR) and survival rate (SR)) no significant difference was observed between diets at the end of the experiment. Furthermore, the addition of 3% K. africana or B. vulgaris or R. heudelotti had no impact on the dry matter, ash, crude protein and whole-body fat content of Nile tilapia fry. This study showed that 3% B. vulgaris or K. africana or R. heudelotti has no adverse effect on the growth, survival and whole-body composition of Nile tilapia fry.

The performance of first generation Of domesticated javaean barb (Systomus orphoides) fry

The existence of native fish in Indonesian waters, especially in West Java, is under threat due to environmental damage. The domestication of javaean barb (Systomus orphoides) is directed to save the existence of this species and provide economic benefits for the aquaculture community. This study aims were to obtain information about the potential production of larvae and fry of javaean barb that was reared in ex-situ. The parameters observed were fecundity, fertilization rate, hatching rate, the survival rate of larvae, fry growth rate, feed conversion ratio, and fry survival rate. The results showed that javaean barb could be spawned ex-situ through induce breeding techniques. Fecundity was 96 632 ± 24 012 eggs/fish with a fertilization rate of 98.3 ± 1.50% and a hatching rate of 64.5 ± 27.10%. The survival rate of 3 days old larvae was 85.2 ± 7.50%. The growth rate of javaean barb fry was positive allometric. The weight-specific growth rate was 4.9 ± 0.22 % with an FCR of 1.7 ± 0.28 and survival rate of 89.3 ± 4.16%. The success of ex situ javaean barb seedling production opens opportunities for developing this species cultivation in the future.

Piscicidal and Prophylaxis Potentials of Neem (Azadirachta indica L) Extract in Yolk Fry of African Catfish, (Clarias gariepinus)

The study aimed to investigate the lethal range and suitable concentration of Neem leaf extract for prophylaxis use in early life stage of African catfish (Clarias gariepinus) by discovering safe dosage, capable of ensuring improved fry survival in the presence of virulent microbial pathogens.&#x0D; Powdered Neem leaf weight 465.00±0.50 g was soaked in ethanol for 72 hours using standard laboratory procedure for metabolite extraction. Extract was freeze-dried through sublimation process. Freeze-dried extracts were characterised for presence and quantity (mg/g) of 12 antimicrobial related metabolites. 100 each of day-old yolk-fry Clarias gariepinus were immersed in each of 0 mg/L, 5 mg/L, 10 mg/L, 15 mg/L, 20 mg/L, 25 mg/L, 30 mg/L, 35 mg/L, 40 mg/L, 45 mg/L, and 50 mg/L freeze-dried extracts, and in each of pre-LC50 Neem concentrations plus 1 x 10-4 Aeromonas hydrophila (ATCC 19750) inoculum in 24 hours; to respectively determine toxicity range (LC50 and LC100) and survival during prophylaxis.&#x0D; Neem leaf yielded 2.94±0.55% freeze-dried extracts. Qualitatively, 58.33% of tested phytochemicals/metabolites were negative, while Saponin, Tannin, Alkaloid, Flavonoid, and Phenol, representing 41.66%tests were positive. Metabolites’ quantity ranged 3.13±0.13mg/g(Phenol) - 14.97±0.15 mg/g(Tannin). Fry in 0-15 mg/L extract did not reach LC50 in 24 hours. LC50 occurred in 20-35 mg/L at 21-23 hours and 40-50 mg/L at 17-18 hours, LC100 occurred in 40-50 mg/L at 19-23 hour. 0%neem+fry had 100.0±0.0% survival in 24 hours. Survival ranged 0.0±0.0 (16-24 hours) - 100.0±0.0%(4-8hours) in 0neem+Fry+Aeromonas; 0.0±0.0(20-24hours) – 100.0±0.0 (4-8 hours) in 5 mg/L neem+Fry+Aeromonas; 0.0±0.0 (20-24 hours) – 100.0±0.0 (4-8 hours) in 10 mg/L neem+Fry+Aeromonas and 30.0±5.5 (24 hours) - 100.0±0.0 (4-8 hours) in 15 mg/L neem+Fry+Aeromonas.&#x0D; Neem extract contain antimicrobial related metabolites, which is toxic to at least half C. gariepinus yolk fry population at &gt;15mg/L concentrations. Fry survival in virulent A. hydrophila laden rearing medium was slightly improved at 15mg/L concentration.

The Effect of Stocking Density on Survival Rate of Siamese Catfish (Pangasianodon hypophthalmus) Fry in Recirculation System

The research aims to determine the best stocking density in the maintenance of Siamese catfish seedlings based on the influence exerted on the survival of Siamese catfish seeds and improving water quality in the recirculation system. This research was conducted at the Green House Ciparanje FPIK Unpad Jatinangor in August 2019. Maintenance activities are carried out in a 70x70x70 cm fiber equipped with a recirculation system and filled with 150 L of water per fiber. The study was conducted with four stocking solid treatments as follows 375 fry/fiber (treatment A); 450 fry/fiber (treatment B); 525 fry/fiber (treatment C); and 600 fry/fiber (treatment D). Siamese catfish fry is 1 inch in size with an average weight of 0.307 grams. The parameters observed were the survival of Siamese catfish fry and water quality. Water quality measurements include temperature, degree of acidity (pH), and ammonia (NH3). Water quality testing was carried out at the Laboratory of Aquatic Resources, Faculty of Fisheries and Marine Sciences, Universitas Padjadjaran. During the study, there was no exchange of water or siphon. The method used in this research was analyzed descriptively and compared the results of survival rate fish and water quality parameters toward the Indonesian National Standard (SNI). The results showed that the best stocking density was 600 fry/fiber with a survival rate of 100% Siamese catfish and the ammonia value at the beginning of maintenance was 0.140 mg/L and the end of maintenance decreased to 0.137 mg/L.

Экструдированные стартовые комбикорма для клариевого сома

Industrial fish-breeding is a promising trend for freshwater aquaculture development. The production of clarid catfish in Kazakhstan has advantages over traditionally grown fish species (trout, sturgeon) due to their valuable edible qualities. Clarid catfish grows very quickly even at high seeding densities, is undemanding to the environment, resistant to diseases, and effectively assimilates food. When growing clarid catfish in water recycling systems it is possible to refuse using oxygen equipment, because the fish species can use atmospheric air for breathing. As a result, the construction of such plants can save up to 40% of capital investments. In the course of the research, the physiological nutritional requirements of clarid catfish juveniles were established. Based on the data obtained there have been developed two extruded starter compound feed recipes for clarid catfish juveniles containing protein/fat 53.5 : 11.4 and 61.85 : 5.82 and energy exchange energy value varying within 16.46 - 17.12 MJ/kg. There have been conducted the production tests on assessing the efficiency of the developed compound feed and their intake by larvae and clarid catfish fry in the fish farms of “Kapshagayskoye NVH-1973”, LLP and “HalykBalyk”, LLP. The feed Aller Agua (Denmark) served as a control feed for comparing the nutritional and consumer qualities of the developed feed for trout. The determined feeding ratio of the developed feed did not exceed 0.93 units, it was insignificantly inferior to the import feed. The fry survival rate made 76% when using both the control and developed feed. The compound feeds for clarid catfish juveniles were developed by extruding, which allowed to obtain increased digestibility, water resistance and extended storage life. Introducing these feeds into the fish breeding practice will help to increase the efficiency of clarid catfish fry growth and expand opportunities of aquaculture facilities.