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Objective: We sought to assess the efficacy of feeding tocotrienol, a member of the vitamin E family, as it impacts physiological functions in fingerling fish. Methods: Fingerling Largemouth Bass Micropterus nigricans with an initial mean body weight (±SD) of 0.98 ± 0.09 g were fed five diets containing tocotrienol at 0, 10, 20, 30, and 40 mg/kg (T0, T10, T20, T30, and T40 diets, respectively) for 42 days. After the feeding experiment, fish were challenged with Largemouth Bass ranavirus (LMBV) and monitored for 48 h. Result: Findings indicated a positive impact of tocotrienol‐supplemented diets on fingerling survival. Furthermore, the weight gain and specific growth rate of fish that received the T30 and T40 diets were significantly higher than those of fish that were fed the T0 diet. Tocotrienol supplementation improved the protein efficiency ratio and condition factor and increased the whole‐body lipid and protein content. Conversely, the hepatosomatic index, viscerosomatic index, and feed conversion ratio were significantly decreased by tocotrienol supplementation. Fish that were fed the T30 and T40 diets exhibited significantly higher hepatopancreas lipase activity and intestinal protease activity. Generally, superoxide dismutase and catalase activities in the liver increased as the tocotrienol level increased. Additionally, the liver malondialdehyde concentration decreased, and there was an improvement in the structure of liver cell tissue. Survival at 48 h after the LMBV challenge was significantly higher in fish that were fed the T30 and T40 diets compared to fish that were given the T0 diet. Maximum specific growth rate was observed at a tocotrienol concentration of 33.63 mg/kg. Conclusion: Results suggest that supplementation of Largemouth Bass fingerling diets with appropriate quantities of tocotrienol can enhance survival, growth, antioxidant capacity, digestion, and uptake of nutrients as well as disease resistance. Impact statementThe survival and growth performance of Largemouth Bass fingerlings were improved by adding tocotrienol at a concentration of 33.63 mg/kg in the diet. [ABSTRACT FROM AUTHOR]

Abstract Newly synthesized vaccines prepared from formalin-killed bacteria Streptococcus pyogenes were investigated in the current study to evaluate the effectiveness of the newly synthesized vaccine as well as their safety by injected intraperitoneal. The study involved several steps 1st step is the preparation of the vaccine followed by the 2nd step: Evaluate the effectiveness and vaccine safety against pathogenic S. pyogenes through 4 different groups including control (Group I). Group II (Bacterial, infected group), Group III (Vaccine), and the Last group was the challenged group after the vaccination (Vacc + Bac). Different Immunological and biochemical parameters were measured in addition to hematological and histopathological examinations. For example, oxidative/antioxidants, inflammatory biomarkers, fragmentation and cell damage, and finally the histopathological study. The current study showed an increase in all oxidative, inflammatory, and cell damage (DNA fragmentation assays), additionally markedly elevation in histopathological cell damage in the infected group (Group II) compared with the control group. The vaccine and challenged after vaccination group (vaccine + Bacteria), showed great improvement in oxidative biomarkers (LPO) and an increase in antioxidants biomarkers (GSH, SOD, GST, DPPH, ABTS, GR and GPx), Also the inflammation and histopathological examination. The newly synthesized vaccine improved the resistance of Oreochromis niloticus and can be used as a preventive therapy agent for pathogenic bacteria S. pyogenes.

Newly synthesized vaccines prepared from formalin-killed bacteria Streptococcus pyogenes were investigated in the current study to evaluate the effectiveness of the newly synthesized vaccine as well as their safety by injected intraperitoneal. The study involved several steps 1st step is the preparation of the vaccine followed by the 2nd step: Evaluate the effectiveness and vaccine safety against pathogenic S. pyogenes through 4 different groups including control (Group I). Group II (Bacterial, infected group), Group III (Vaccine), and the Last group was the challenged group after the vaccination (Vacc + Bac). Different Immunological and biochemical parameters were measured in addition to hematological and histopathological examinations. For example, oxidative/antioxidants, inflammatory biomarkers, fragmentation and cell damage, and finally the histopathological study. The current study showed an increase in all oxidative, inflammatory, and cell damage (DNA fragmentation assays), additionally markedly elevation in histopathological cell damage in the infected group (Group II) compared with the control group. The vaccine and challenged after vaccination group (vaccine + Bacteria), showed great improvement in oxidative biomarkers (LPO) and an increase in antioxidants biomarkers (GSH, SOD, GST, DPPH, ABTS, GR and GPx), Also the inflammation and histopathological examination. The newly synthesized vaccine improved the resistance of Oreochromis niloticus and can be used as a preventive therapy agent for pathogenic bacteria S. pyogenes. [ABSTRACT FROM AUTHOR]

Microplastics are an emerging pollutant of marine environments, affecting fish and other marine biota such as copepods and rotifers. The current study assesses the impact of plastic microbeads on the growth of roho (Labeo rohita) in a 4-month feeding experiment under laboratory conditions. Over a period of 120 days, roho fingerlings were exposed to different concentrations of plastic microbeads (50 mg to 200 mg/kg of feed) mixed into their feed. It was found that the ingestion of plastic microbeads negatively affected the growth of roho and that the concentration of the plastic microbeads directly influenced the growth rate of the fish. [ABSTRACT FROM AUTHOR]

As tilapia aquaculture expands globally, cold sensitivity remains a critical issue, leading to significant losses due to poor growth, disease susceptibility, and high mortality. This study evaluated the cold tolerance in fry of three tilapia varieties, incorporating a comprehensive analysis of 3240 specimens. The fry, segregated by variety into different tanks, were observed during summer to assess their performance. The study focused on two commercially prominent varieties, known for their rapid weight gain, and a third variety developed by the Federal University of Lavras, specifically bred for resilience to local climatic conditions. Following a 15-day acclimation period in experimental tanks, the fry were monitored for feeding to apparent satiety. Daily assessments included counting mortalities and measuring water temperature and dissolved oxygen levels. Survival data were analyzed using multivariate Cox regression, with survival curves derived via the Kaplan-Meier method. Lifespan predictions from these curves were compared using the log-rank test. Results indicated that older fry were more resilient to cold stress. Notably, the MGTUP variety, bred for local environmental adaptability, demonstrated superior cold tolerance. This variety also exhibited the lowest mortality rates across all age groups. These findings suggest that utilizing locally adapted tilapia varieties can significantly mitigate losses in aquaculture, especially in cold-prone regions.

This study investigated the use of black soldier fly (Hermetia illucens) larvae (BSFL), provided in either full-fat (FBSF) or defatted (DBSF) forms, as an alternative protein source in the diet of Nile tilapia (Oreochromis niloticus) fingerlings. Specifically, the influence was assessed of BSFL on growth performance, hematological parameters, body composition, and histology. Nine diets (including the control) were formulated to be isonitrogenous (35 % crude protein) and isolipidic (6 % crude lipid), relying on fish meal as the primary protein source and gradually replacing it with BSFL meal at levels of 25 %, 50 %, 75 %, or 100 % on an equivalent protein basis, corresponding to dietary inclusion levels of 5.25 %, 10.25 %, 15.5 %, and 20.0 %, respectively. Fish with an initial mean weight ± standard deviation of 1.3 ± 0.26 g were fed for 12 weeks until the fish final weight was in the range 24.08–34.95 g. Based on the results, there were no significant (p>0.05) differences in the growth performance or feed conversion ratios among the treatments. Additionally, there were no significant differences in the hematological responses or the proximate body composition. Furthermore, 100 % substitution of fish meal with FSFL and DBSF meal caused blood congestion in the hepatopancreas region and several intraepithelial leukocytes in the intestine. There were no detrimental impacts at levels of 25 %, 50 %, and 75 % on growth performance, hematological responses, body composition, or the intestines or liver histological characteristics of the O. niloticus fingerlings. This information should provide useful guidance for the management of Nile tilapia, an economically important species.

ABSTRACTFishes are hosts to a range of taxonomically diverse parasites. This survey was intended to provide insight into the occurrence, distribution, prevalence, and intensity of parasites infesting the fingerlings of the tilapia, in Tigray. A total of 384 Oreochromis niloticus specimens were collected from Midmar consisting of 227 males and 157 females. External and internal organs were examined for parasite infection. Squash preparation of fish eyes was also examined to reveal the organisms through microscopic examination. The major groups of parasites were trematode, nematodes, protozoa and hirudinea. A total of 3762 genus Diplostomum were recorded affecting the health of 93% of fishes. Contracaecum species was the second most prevalent distributed majorly in the intestine (77.8%), pericardial cavity (19.1%), swim bladder (2.4%), gill (0.2%) and mouth (0.8%). The prevalence and mean intensity of Diplostomum spp., Contracaecum, Myxosporea, Clinostomum spp., Eustrongylides and Leeches was 93%(10.5), 62.2%(5.3), 39.3%(8.3), 2.1%(8.8),1.8%(5.7) and 1.6% (2.5), respectively. The mean temperature, dissolved oxygen, conductivity, and pH of the dam were 24.4°C, 7.55 mg/l, 849.5µs/cm, and 7.5, respectively. Therefore, responsible bodies in fisheries should perform a pre-stock assessment and provide fish farming extension services for optimum production and marketing of fish products with management and production enhancement methods.

The research was conducted to evaluate the use of sugar cane yeast (Saccharomyces cerevisiae) dehydrated by the spray dryer method in the diets of Nile tilapia. We used 144 fingerlings with average initial weight 3.6 ± 0.03 g, distributed in 24 tanks with a capacity of 80L, connected to a recirculating water system, using a biological filter for the mineralization of ammonia to nitrite, and nitrite to nitrate, and a continuous aeration system. The experimental design was completely randomized design consisting of four treatments (0.00, 10.00, 20.00 and 30.00% inclusion of yeast) and six repetitions. The experiment last 60 days and was evaluated the final weight, total length, survival rate, weight gain, feed intake, apparent feed conversion, protein efficiency rate, carcass yield, hepatosomatic and liposomatic index. Regarding the analyzed parameters, no significant effect was observed for total length, feed intake, feed conversion, protein efficiency rate, carcass yield, hepatosomatic and liposomatic index. However, the final weight and weight gain showed a quadratic effect, with the best level of yeast inclusion indicated by the regression for these parameters were 2.26 and 3.04%, respectively. As for the survival rate of the animals, a linear increase was observed. Based on the results obtained, the inclusion of 3.04% of yeast for Nile tilapia fingerlings is recommended. [ABSTRACT FROM AUTHOR]

The article presents the results of research on the growth dynamics of rainbow trout from fingerling to marketable fish using feeds with different compositions of components and nutrient contents. For the experiment, two age groups of rainbow trout individuals, control and experimental, were formed, which were kept in tanks with a total volume of 30 m3 and fed with feeds with different nutrient contents. For feeding the experimental fish, dry pelleted feed for trout was used, which has an optimal balance of cost and nutritive value, resulting in high growth rates with a low feed coefficient. The feed is made from high-quality Ukrainian ingredients with good nutritional and flavor characteristics, stimulating fish feed intake, and is balanced in terms of essential nutrients and biologically active substances, which positively affects the physiological condition of salmonid fish and their growth rates. The daily ration was determined depending on the fish's weight and the water temperature in the tanks according to the feed manufacturer's recommendations. The effectiveness of using pelleted compound feeds for trout was evaluated based on indicators such as fish survival, fish productivity, and feed consumption. At the same time, the physicochemical parameters were monitored throughout the entire experimental period. The duration of growing rainbow trout fingerlings was 245 days. As a result, 3230 specimens of fingerlings with a mass of 25.6 g were obtained in the control, and 3400 specimens were obtained in the experiment with a mass of 28.5 g. The yield from the cultivation was 76 % and 80 %, respectively. Fish productivity was slightly higher in the basin where the experimental group of fingerlings was kept. The total weight of the harvested fish from the experimental group was greater by 14.2 kg. To obtain marketable products, rainbow trout fingerlings were stocked in 30 m3 tanks. The average weight of fish in the control group at stocking was 25.6 g, and in the experimental group, it was 28.5 g. 3100 specimens of fingerlings were stocked in each tank. The duration of cultivation was 215 days. 2805 specimens were harvested from the tanks, 250.5 g from the control tank, and 268.5 g from the experimental tank. The total weight of the harvested fish and fish productivity were slightly higher in the fish from the experimental group. As a result of the conducted research, it was established that feeding fish with feeds differing in nutritional value contributes to increasing the productivity of rainbow trout farming. [ABSTRACT FROM AUTHOR]

AbstractThis study investigated the application of anaesthetics in 23 private and government-owned hatcheries in 10 provinces of Zambia. The study employed both qualitative and quantitative research designs and used a structured questionnaire to collect data from the respondents. The results showed that most hatcheries (65%) were not using anaesthetics in handling fish and all (100%) that were using anaesthetics (35%) used clove powder as the only type. Most respondents (61%) were not sure or did not have information about the availability of the anaesthetic substances in their localities while only 26% reported wider availability but 13% had a divergent claim. The mortality rate for fingerlings in hatcheries that applied anaesthetics ranged between 15–30% with consistently high demand while those that did not use anaesthetics reported mortality rates of more than 50% and had low demand. The majority of the respondents (53%) had received training up to certificate level, followed by those who had attained up to a diploma qualification (27%) while those that attained up to a degree (13%) and general skills (7%) levels were in the minority. Furthermore, most respondents (35%) did not know the importance of fish anaesthetics. We conclude that the use of fish anaesthetics in Zambian hatcheries is very low and could partly be the cause of high fingerling mortalities, and there is an urgent need to address the situation.

Aquaculture contributes significantly to the food source for human consumption. Tilapia Oreochromis niloticus is one of the main fish in aquaculture production, so its reproduction phases are vital to ensure the quality and quantity of organisms available for production systems. The reproductive parameters in fish aquaculture activities, such as fertility, fecundity, egg diameter, gonadosomatic index, survival rate in larvae and fingerlings, among others, are relevant for an economically profitable and sustainable production, and these can vary according to the diet, environmental conditions, age, genetic characteristics of the fish or the quality of the water. Therefore, this document aims to identify the reproductive parameters that influence on the production of fingerlings tilapia to present a general description in a simple way of the different reproductive parameters involved in aquaculture production activities of fingerlings tilapia. A search of the information in the last 20 years incorporated in various specialized databases was carried out. In this research, information is compiled to date on the reproductive parameters in tilapia, the results indicate that there is no more important reproductive parameter than another, since it is a cluster of factors and synergy that intervene in reproduction, hence it is necessary to establish clear management plans and research in the production systems to improve and enhance their production. Knowing the reproductive parameters of tilapia can help reduce production costs, thus it is necessary to establish clear management plans and research in production systems to improve and enhance their production. [ABSTRACT FROM AUTHOR]

Paraquat is a toxic chemical used as a broad spectrum, contact herbicide for aquatic weed control in many countries including Nigeria that has been implicated in many non-target effects in the environment. Clarias gariepinus, an important fish in aquaculture in Nigeria is also used as a bio-indicator species, as it plays an increasing important role in the monitoring of water pollution because it responds with great sensitivity to the changes in the aquatic environment. Therefore, this study investigated the effect of paraquat-based herbicide on the survival C. gariepinus fingerlings. Fingerlings were exposed to three concentrations of paraquat viz 3.44ml, 6.88ml and 13.75ml in tanks of 5 replicates. Percentage mortality was recorded after 24, 48 and 72-hour exposure. Paraquat exhibited a high degree of mortality against fingerlings, but the observed mortality was observed to be concentration and exposure time dependent. All concentrations used were below the manufacturer’s recommended concentration for aquatic weed control and they caused between 85 to 100% mortality after 72-hour exposure. Results from this study suggest that paraquat is highly toxic to C. gariepinus fingerlings and can therefore serve as reliable indicators of toxicity in environmental impact assessment programmes. Studies focusing on the effects of paraquat on aspects of the behaviour and physiology of juvenile stages of C. gariepinus are needed to fully understand the effects of this herbicide as results like this study show that paraquat can affect food supply (protein) and income to fish farmers.

Paraquat is a toxic chemical used as a broad spectrum, contact herbicide for aquatic weed control in many countries including Nigeria that has been implicated in many non-target effects in the environment. Clarias gariepinus, an important fish in aquaculture in Nigeria is also used as a bio-indicator species, as it plays an increasing important role in the monitoring of water pollution because it responds with great sensitivity to the changes in the aquatic environment. Therefore, this study investigated the effect of paraquat-based herbicide on the survival C. gariepinus fingerlings. Fingerlings were exposed to three concentrations of paraquat viz 3.44ml, 6.88ml and 13.75ml in tanks of 5 replicates. Percentage mortality was recorded after 24, 48 and 72-hour exposure. Paraquat exhibited a high degree of mortality against fingerlings, but the observed mortality was observed to be concentration and exposure time dependent. All concentrations used were below the manufacturer's recommended concentration for aquatic weed control and they caused between 85 to 100% mortality after 72-hour exposure. Results from this study suggest that paraquat is highly toxic to C. gariepinus fingerlings and can therefore serve as reliable indicators of toxicity in environmental impact assessment programmes. Studies focusing on the effects of paraquat on aspects of the behaviour and physiology of juvenile stages of C. gariepinus are needed to fully understand the effects of this herbicide as results like this study show that paraquat can affect food supply (protein) and income to fish farmers. [ABSTRACT FROM AUTHOR]

Purpose.To investigate the peculiarities of pikeperch fingerlings (Sander lucioperca Linnaeus, 1758) cultivated with the use of pool technology and different stoking densities, also to provide a comprehensive fishery-biological assessment of the produced fish. Methodology. The material for the study were juvenile and young-of-the-year pikeperch. They were cultivated in 17.3 m3 pools (in the first series of the experiment) and 2.16 m3 pools (in the second series of the experiment). According to the physiological needs of pikeperch at the studied stage of ontogenesis, its diet consisted of salt brine shrimp (Artemia salina Linnaeus, 1758) nauplii and combined feed. They were fed according to a scheme with a sequential change of 3 stages: 1 – feeding exclusively with brine shrimp nauplii; 2 – combined feeding (brine shrimp nauplii and combined feed were mixed); 3 – feeding exclusively with combined feed. Also, 3 options of stocking density were used at each of the above-mentioned growing stages. Namely: at the 1st stage ‒ 40, 60 and 80 thousand individuals/m3; in the II stage ‒ 10, 15 and 20 thousand individuals/m3, and in the III stage ‒ 5, 7, 10 thousand individuals/m3. During the entire growing process, according to the schedule, test catches were carried out, during which weighing was carried out, based on the results of which absolute and relative weight gains were calculated. Statistical processing of the received data was carried out using a package of standard Microsoft Office software. Findings. The study established that the highest growth rates were found in fish that were grown at the stocking density: at first 40 thousand individuals/m3 (I stage), and then 10 thousand individuals/m3 (II stage) and 5 (III stage) individuals/m3 after that — experimental group No 1. The individual weights in the fish from this experimental group were 1.7–1.8 g at the first stage of rearing, and at the second stage of rearing, the intensity of weight accumulation in them increased almost twice (2.4–2.2 g). The survival rate of fish from the experimental group No 1 was 37.5–41.0% at the I stage of rearing and 74.0–78.0% at the II stage. Under such scheme (feeding and stocking density as in experimental group No 1) of pikeperch juveniles and young-of-the-year cultivation in pools, the fish productivity of the latter ranged from 21 to 35.8 kg/m3 (depending on the initial size of the pools for rearing). Originality.For the first time in the conditions of Ukraine, a comparative analysis of young-of-the-pikeperch cultivation using intensive technology was carried out, and practical recommendations were given to improve the existing technology. Practical Value. The use of the pool method of young-of-the-pikeperch cultivation allows expanding the existing technologies of aquaculture for this fish species and increase the market of its additional products.

The helminths of fingerlings of the gray toad Bufo bufo (Linnaeus, 1758) have been studied in some specially protected natural areas (protected areas (PAs)) of the Urals. Only four species of helminths belonging to a Nematoda type are found. The nematodes Oswaldocruzia filiformis and Rhabdias bufonis are common for the studied populations of amphibians. The species composition of geohelminths does not differ in fingerlings or sexually mature amphibians; the infection in adult toads is higher than in fingerlings. The analysis of helminth fauna in the gray toad demonstrated that the nematodes Oswaldocruzia filiformis and Rhabdias bufonis dominate in Bufo bufo in most regions of Russia. The richest species composition of trematodes is noted in the gray toads of Mordovia. [ABSTRACT FROM AUTHOR]

Rapidly increasing hatchery-raised Nile tilapia (Oreochromis niloticus) in most developing countries lack informed recommended fingerling weight for stocking in semi-intensive grow-out ponds. The current study assessed the growth performance, survival and productivity of all-male Nile tilapia fingerlings of 0.2 g, 1 g, and 5 g in an on-farm experiment. The final mean weight of fingerlings stocked at size 5 g was significantly higher (113.80±4.21 g) (P<0.05) compared to the 0.2 g (36.99±1.14 g) and 1g (91.93±5.59 g) fingerling sizes. The mean daily weight gain was highest in 5 g stocked fingerlings (0.91±0.04 g day -1) resulting in significant differences in the final mean weight. The coefficient of correlation between fish body length and weight was high and positive ranging (R=0.95-0.98). Significantly low percent survival was recorded in 0.2 g stocked fingerlings (64.4 3±1.93%). The net annual fish yield (NAY) and profit index (PI) were significantly lower at the 0.2 g. The highest NAY and PI were recorded in the 5 g stocked fingerlings (8.59±0.09 tons ha-1 year-1 and 6.6±2.08), respectively. Thus, with appropriate Nile tilapia fingerling weight at stocking, fish farmers can maximize fish growth, yield and profits. [ABSTRACT FROM AUTHOR]

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This study was conducted to evaluate the efficiency of isolates of probiotic bacteria Lactobacillus acidophilus 4453 and Streptococcus thermophiles 5935 on performance of common carp fingerlings which had initial body weight attained (44±0.69) g. A total of 72 fish were used and randomly divided into 4 treatments with 3 replicates (6 fish per replicate). An experimental diet was prepared with a crude protein attained (29.14%) and gross energy of 417.95 kcal / g. The probiotics were prepared in the form of bacterial suspensions at a dilution of (10-7 cfu/ml) and were added to the suspension of 20% Arabic gum and phosphate buffer salt as an enveloping and adhesive material of bacterial cells to increase their stability and survival on feed pellets. The liquid probiotics were added to specified amounts of the experimental diets according to the following treatments (T0 control treatment, T1 Lactobacillus acidophilus 4453, T2 Streptococcus thermophiles 5935, and T3 Lactobacillus acidophilus 4453 + Streptococcus thermophiles 5935). Fish performance was assessed after 83 days of the experiment according to weight gain, daily growth rate, relative growth rate, specific growth rate, metabolic growth rate, feed conversion rate, feed conversion efficiency, and protein efficiency ratio. The results of the statistical analysis showed that all the probiotic treatments were significantly exceeding as compared with T0 in the following order T1 and T3 with no significant difference followed by T2 of the weight gain, daily growth rate, relative growth rate, specific growth rate, and metabolic growth rate, whereas T1, T2, and T3 gave the best feed conversion rate, feed conversion efficiency and protein efficiency ratio. Therefore, we conclude that the single and multi-bacterial isolate probiotics of Lactobacillus acidophilus 4453 and Streptococcus thermophiles 5935, within the conditions of this study, were highly influential in achieving the best utilization of the food intake and the best performance of common carp fingerlings. [ABSTRACT FROM AUTHOR]

The toxicity and behavioural response of fingerlings of Clarias gariepinus (mean total length, 5.04± 0.7cm; mean body weight 4.05 ± 0.3g) to inorganic fertilizers (NPK, 20:10:10) was studied under laboratory conditions to determine the acute toxicity of NPK, 20:10:10 fertilizer to fingerlings of Clarias gariepinus using a static bioassay test. The fingerlings were exposed to increasing concentrations of NPK, 20:10:10 (0.00g/l, 8.00g/l, 12.00g/l, 16.00g/l and 20.00g/l) fertilizer in the static renewal bioassay for 96 hours. Exposed fish showed behavioural responses such as agitated swimming, air gulping, restlessness, loss of balance, caudal, frequent attempts at jumping out of the tank and quietness. Water quality examinations showed a decrease in the dissolved oxygen content and increase in total hardness and alkalinity as the concentration of fertilizer was increased. Clarias gariepinus fingerlings were more susceptible to fertilizer NPK, 20:10:10 at higher concentrations as indicated by the percentage of death in the results and the LC50= 12g/L, safety limit =1.20g/L. The concentrations of the toxicants were dose dependent and caused changes in skin colouration of the fish, mortality was highest in the highest concentration of fertilizer and no mortality in the control. Mortality rates were concentration-dependent and death rate in the highest concentrations were significantly higher (P<0.05) than the others. Mortality rate was influenced by both concentration and time. The findings from this study show that NPK, 20:10:10 fertilizer could be classified as toxic to Clarias gariepinus fingerlings at certain concentrations. [ABSTRACT FROM AUTHOR]

A 10-week feeding trial was carried out to evaluate strain-specific effects of Lactobacillus plantarum on blood profiles of African catfish Clarias gariepinus fingerlings. A catfish diet was formulated and divided into five portions (experimental diets). The first portion served as control (with no probiotic added to it, labeled as NP) while the second portion received 2.5g kg-1 multi-species commercial probiotics (CP). The third, fourth and fifth portions were the experimental diets that contained 2×109cfu/g of L. plantarum strains of ascension numbers LC333558, LC333559 and LC333560, and labeled as LP58, LP59 and LP60, respectively. Fifteen apparently healthy C gariepinus fingerlings (4.86±0.59g) were stocked in an experimental tank of 70 litres capacity, while the experimental feed was fed to the fish in triplicate tanks. Similar rearing conditions were maintained in all experimental tanks. The results showed significant (p<0.05) difference between the fish fed control diet and probiotics supplementation diets in some of the haematological parameters examined. Probiotics supplementations did not affect total and differential leukocytes among different experimental groups. Except for RBC counts, fish groups fed with strains LB59 and LB60 had similar effects and appeared to have better haematological values than groups fed with LB58. Strains-specific effect of L. planatrum was also observed in creatinine levels among the experimental groups. Hence, it can be concluded that strains of L. plantarum affected some haematological parameters of C. gariepinus fingerlings positively, while dietary supplementation of L. plantarum LC333559 strain could be employed to improve haematological parameters of C. gariepinus fingerlings. [ABSTRACT FROM AUTHOR]

RESUMEN | El cultivo de Oreochromis spp., representa una base económica en diferentes países debido a que la especie muestra diversos grados de tolerancia a factores fisicoquímicos y un rápido crecimiento. En esta investigación se evaluó el efecto de la inclusión de Lens culinaris en dietas de alevines de tilapia. Los alevines tuvieron pesos y tallas similares de 1,20 g ± 0,01 y 2,9 cm ± 0,01, respectivamente. Los alimentos fueron racionados cuatro veces al día donde se determinó el efecto del crecimiento mediante diferentes niveles de sustituciones (0, 80, 50 y 20 %) de harina de lenteja. Los índices productivos analizados fueron: tasa de crecimiento, tasa de eficiencia, factor de condición y conversión alimenticia. Se observaron diferencias significativas entre las dietas en cuanto al peso, talla y tasa de crecimiento específico, siendo el control eficiente con respecto a los demás tratamientos. De acuerdo, a este estudio L. culinaris puede ser incluida hasta un 20 % para la alimentación en alevines de Oreochromis spp sin afectar los parámetros productivos. ABSTRACT | The culture of Oreochromis spp., represents an economic base in different countries because the species shows various degrees of tolerance to physical-chemical factors and rapid growth. In this study, the effect of the inclusion of Lens culinaris in diets of tilapia fingerlings was evaluated. The fingerlings had similar weights and sizes 1.20 g ± 0.01 y 2.9 cm ± 0.01, respectively. The feed was rationed four times a day where the effect on growth was determined by different levels of substitutions (0, 80, 50 and 20 %) of lentil flour. The productive indexes analyzed were: growth rate, efficiency rate, condition factor and feed conversion. There where significant differences among diets with respect to weight, length and specific growth rate with the control being efficient with respect to the other treatments. According to this study, L. culinaris can be included up to 20% for the feeding of Oreochromis spp., fingerlings without affecting the productive parameters.

The purpose of this research is aimed to bring an alternative solution for the raising of fry in aquatic ponds, through the control and monitoring of water temperature, in order to optimize their development and growth, regardless of the habitat where they are located, improving the production of fish for mass consumption even in places where the climate is not suitable for their raising. The above-mentioned control and monitoring was carried out through the cost-effective Atmega328P microcontroller that make easier its configuration and implementation. This type of research is applied because it gives solution to the problem in optimize the fry raising in aquariums and was divided into the following stages for temperature control: first, the sensor measures the temperature and compares it with a mobile application baseline; second, the water temperature is stabilized by the electronic thermostat; finally, the water temperature is conditioned to get a healthy habitat for the fry. All of this is executed remotely through an application created to be used from a cell phone. Concluding, the right parameters are found to stabilize the water temperature effectively.

This study aimed to assess the effects of the addition of probiotics and sodium citrate to the diet of Asian swamp eel (Monopterus albus) fingerlings, on growth performance and gastrointestinal microbiota. Before the start of the experiment, the fingerlings were acclimatized for two days; 480 fingerlings were distributed equally in 12 tanks containing 50 l of fresh water. Treatments were designed as follows: (T1) control fed with commercial feed, (T2) feed coated with sodium citrate, (T3) feed coated with probiotics and (T4) feed coated with sodium citrate mixed with probiotics. The results of this study showed that both probiotics and the mixture of sodium citrate with probiotics improved growth, stimulated total bacteria, and reduced the number of Vibrio in the gastrointestinal tract of M. albus.

Passive Integrated Transponder (PIT) tags have been popularly used in identification of individual fish, stock, full-sib and half-sib families, year class and generations in aquaculture selective breeding programs. This study has been conducted on genetically improved Indian Major Carps (IMCs), improved rohu (Jayanti) and improved catla to compare PIT tagging of different size taggable fingerlings with respect to post tagging survival and tag retention. Six groups of improved rohu (Jayanti) and improved catla fingerlings with weight ranging from 10 to 150 g were tagged with PIT tags and mortality was recorded after 24 h. The overall mortality was thus found to be 3 % and 15 % in rohu and catla respectively. In rohu, 3 % mortality was observed after tagging in both small size fish ( 20 g) with no significant difference whereas in catla, mortality in small size fish ( 20 g) (p 0.05), whereas in catla the correlation of length, weight and tagging space on mortality % was − 0.508, − 0.510, − 0.500 respectively and significant (p 0.05). This study also revealed more sensitivity of the Indian major carp Labeo catla (Catla) to PIT tagging in comparison to Labeo rohita (rohu) and demonstrates the ideal size for PIT tagging in catla to be 20–30 g.

This study was conducted to evaluate the effect of citric acid (CA) treated Moringa oleifera seed meal (MOSM) based diet on mineral absorption, carcass composition and hematological indices in Cirrhinus mrigala fingerlings. Basal diet was supplemented with 0%, 1%, 2%, 3%, 4% and 5% CA resulting in the formulation of six experimental diets. Ten fingerlings were stocked in tanks in triplicate for each treatment. Feed was given at 5% live wet body weight of fingerlings for 90 days. Results showed that diet acidification with CA significantly (p< 0.05) improved the mineral absorption, carcass composition and hematological indices of C. mrigala fingerlings compared to control diet. Data shows that mineral absorption was higher (p=0.05) at medium levels of CA supplementation (2%, 3% or 4% levels) compared to extreme levels (1% and 5%). Maximum body crude protein and crude fat contents were observed in C. mrigala fed 2 % and 3% CA supplemented diets, respectively. Moreover, fingerlings fed CA acidified diets showed significant improvement (p< 0.05) in hematological parameters compared to control diet. Comparison of treatments showed maximum values of RBCs (2.83×106mm-3), WBCs (7.76×10³mm-3), PLT (65.96), Hb (8.47 g/100ml), PCV (24.51 %), and MCV (187.11 fl) in fingerlings fed 3% CA supplemented diet. In conclusion, 3% CA acidified MOSM based diet performed better regarding mineral absorption, carcass composition and hematological indices C. mrigala fingerlings. [ABSTRACT FROM AUTHOR]

This research is done to reveal the effect of water flow on the round container to increase the growth and survival rate in bonylip barb. The method used in this research is an experimental method using a Completely Random Design (CRD) which is consist of three treatments and five repetitions. The treatments are round container without water flow (A), round container with 0,1 m s-1 of water flow (B) and round container with 0,1 m s-1 of water flow with an additional venturi aerator. The numbers of bonylip barb fingerlings used in this research are 900 with a length of 1-3 cm. The container used in this research is 15 water gallons with a volume of 19L. The density of the container is 60 fish per container. Fish maintained for 40 days. The feeding rate given is 5% of the biomass. The observed parameters are survival rate, daily growth rate and feed conversion ratio observed every 10 days. The result showed that the water flow combined with the venturi aerator give the best result with 77.3% of survival rate, 3.12% of daily growth rate and 1.42 feed conversion ratio. [ABSTRACT FROM AUTHOR]

This community programme has been carried out in the UPR Karper Mina Group, Tanjungkerta District, Sumedang Regency, West Java, with the aim of providing knowledge and skills in cultivating natural feed Chlorella and Artemia feed as one type of natural feed for fish fingerlings. The methods used in this program include: field surveys and observations, socialization, counselling, making hemp feed cultivation media, cultivating natural feed and mentoring. The provision of natural feed for fish fingerlings cultivation has been carried out by capturing from nature, so that cultivators should have the ability to cultivate independently to maintain the quantity and quality of natural feed. The results of the survey and field observations indicated that there were potential sources of natural feed and human resources that can be optimized to support fisheries activities, including the cultivation of natural feed to increase the production of fish fingerlings. The target community group consisted of fish breeders who are members of the UPR Karper Mina Group. The first stage was counseling on the potential and important role of livelly feed in fish hatchery activities. After counseling about the types of natural feed and the media used for their cultivation, the practice of cultivating natural feed Chlorella and Artemia types was then carried out. The result of this activity is that the community understands the urgency of natural feed for the growth of fish fingerlings, knows the types of natural feed and can cultivate it independently. [ABSTRACT FROM AUTHOR]

This study aimed to determine the lysine requirement in tambatinga fingerlings (Colossoma macropomum × Piaractus brachypomum) using different diet formulation techniques. A total of 1,800 fingerlings (0.82 ± 0.39 g) were fed for 52 days with six isoenergetic diets (3,000 kcal energy kg−1) containing different levels of lysine (12.9, 14.8, 16.6, 18.5, 20.4 and 22.2 g kg−1) were formulated using amino acid supplementation and diet dilution techniques. There was a linear effect on lysine intake and a quadratic effect for weight gain, specific growth rate, feed conversion ratio, lysine efficiency for weight gain and fish body protein deposition up to estimated levels of 19.15; 19.43; 19.28; 15.92 and 19.27 g kg−1, respectively. Fish‐fed diets formulated by the dilution technique exhibited higher performance and body protein deposition. Body fat deposition and nitrogen retention efficiency of fish‐fed diets formulated by the supplementation technique increased up to estimated levels of 17.96 and 19.06 g kg−1, respectively. The recommended lysine level in diets for tambatinga fingerlings is 19.27 g kg−1, for providing greater performance and body protein deposition of fishes, and dilution technique can be used in experimental fish diets formulation. [ABSTRACT FROM AUTHOR]

Growth performance of 17 alpha-methyl testosterone treated monosex and hormone untreated mixed sex tilapia was done for a period of 180 days in cages adjacent to Lwanda Disi beach, Lake Victoria, Kenya. Mixed sex Nile tilapia is known for frequent spawning in culture systems, resulting to fish with varied sizes and stunted growth. To attain male monosex fingerlings, the newly hatched fry were sex reversed by feeding them a diet laced with 17-alpha-methyl testosterone hormone for 21 days. Thereafter, the fry were fed 40% crude protein (CP) diet until stocking into cages. Mixed sex fry of same cohort were fed 40% crude protein starter diet until the time of stocking. A total of 6 cages (2×2×2 m) were randomly stocked with 1000 male monosex and mixed sex fingerlings. The individual mean (± SD) weight at stocking was 9.5 ± 0.06 g and 8.8 ± 0.08 for monosex and mixed sex, respectively. The experimental fish were fed starter diet 40% CP at 10% of body weight for the first two months. From the third month till the end of the experiment, the fish were fed 30% CP diet at 3% of body weight. Measurement of fish total length, body weight and selected water quality parameters was done once a month. There was a significantly higher (P < 0.05) mean body weight gain (BWG), specific growth rate (SGR) and condition factor (CF) for male monosex fish. Conversely, Feed conversion ratio (FCR) was significantly higher (P < 0.05) in mixed sex Nile tilapia. Survival rates (%) and water quality parameters did not differ between the groups. Though the mixed sex Nile tilapia did not reproduce in cages they performed poorly compared to male monosex. [ABSTRACT FROM AUTHOR]

Waste dry cell batteries are frequently improperly disposed and subsequently washed into water bodies-- causing deleterious effects on fish particularly Clarias gariepinus which inhabits diverse freshwater habitats. Acute toxicity of water-soluble fractions of waste dry cell batteries was investigated on C. gariepinus fingerlings under laboratory conditions in 96 hours. Ten (10) C. gariepinus fingerlings were exposed to acute concentrations (0.31, 0.63, 1.25, 2.50, and 5.00 g/L) of waste dry cell batteries and a control (0.00 g/L), each duplicate replicated. Histopathological alterations evident in the gills were lamellar fusion, hyperplasia, inter-lamella space occlusion, hypertrophy and erosion of secondary lamellae. The liver showed nuclear and hepatocytes degeneration, vacuolation and portal congestion. Acute concentrations of water-soluble fractions of waste dry cell batteries caused significant (P<0.05) changes in the histomorphology of the gills and liver of C. gariepinus fingerlings, therefore indiscriminate disposal of waste dry cell batteries around riparian ecosystem should be safeguarded to reduce the declining diversity and abundance of freshwater fish species. [ABSTRACT FROM AUTHOR]

The inevitable process in aquaculture is seed transportation practice before farming begins at the young stage or grow outs. This study aims to optimize the packaging density of rohu (Labeo rohita) fingerlings for different hours of transport. In this study, we investigated the changes in water quality and survival of transported fish. The fish of size 10.28 ± 1.84 cm used and packed in oxygenated polythene bags (the Closed type of transportation) with four packing densities viz., 70 g L-1, 140 g L-1, 210 and 280 g L-1 and were transported for the periods of 4 and 8 hours. Cumulative mortality of 38.39 ± 1.34% was recorded after transportation of 4 and 8 hrs of fish transportation group at 3 (210 g L-1); while the other two packing densities recorded no mortalities. Low levels of dissolved oxygen and high levels of ammonia-nitrogen were noticed in different packing densities after transportation. The results suggested that the optimum packing density for advanced rohu fingerlings for 4 hrs and 8 hrs duration of transport would be 140 g L-1 and 70 g L-1, respectively which kept the stress at low levels. [ABSTRACT FROM AUTHOR]

Purpose. To determine the effects of specific elements of biotechnologies used for rearing sterlet and paddlefish seeds for the optimization of rearing technology and their rational use in pond fish facilities of Southern Ukraine. Methodology. Rearing of young-of-the-year sterlet and paddlefish was conducted in experimental ponds (2 ha and 3 ha). In order to develop appropriate natural food supply, we added mineral and organic fertilizers (5 tons/ha). Rearing of YOY sterlet was conducted with different stocking densities (65000 and 95000 fish/ha), the control variant had 100000 fish/ha. Rearing of YOY paddlefish was conducted with a stocking density of 500 and 1500 fish/ha. Mean individual body weight while stocking experimental ponds was 69–75 mg (sterlet) and 600–700 mg (paddlefish). Findings. Results of rearing were analyzed and fishery performance of sterlet (Acipenser ruthenus L.) and paddlefish (Polyodon spathula (Walbaum)) reared according to the combined technology were analyzed. We examined pond food supply composition (phytoplankton, zooplankton, zoobenthos), growth and nutrition of YOY sterlet and paddlefish. It was found that a stocking density of 79000 fish/ha and abundant food supply for YOY sterlet can result in mean individual body weight of 3.60–4.40 g, survival rate –– 70.32– 82.78%, fish productivity –– 238.09 kg/ha. Stocking ponds with paddlefish with individual body weight of 600–700 mg and stocking density of 500-1500 fish/ha resulted in obtaining young-of-the-year with mean individual body weight of 278.0-409.8 g, survival rate –– 25.4–31.2%. Scientific novelty. Our experiment allowed better understanding of the correlation between stocking density and results of the rearing of sterlet and paddlefish seeds. We found a clear correlation between mean individual body weight, stocking density and duration of rearing for YOY sterlet. We found an effect for some biotechnological aspects on biochemical indicators of YOY sterlet. Practical value. The obtained data enriches and refines existing representation of the correlation between technological factors and efficiency of rearing viable sterlet and paddlefish seeds in the conditions of southern Ukraine and contributes to finding optimal parameters of rearing in terms of modern aquaculture.

Data on exogenous feeding in the early life stages of sturgeon in the wild and in aquaculture are analyzed. The data on food composition and feeding habits in sturgeon larvae at the stage of transition to exogenous feeding and some later in the wild are conflictive. Some data demonstrate that larvae, upon their transition to exogenous feeding, feed on zoobenthos; other data show that larvae at this stage of development feed on planktonic crustaceans and only in the fingerling period do sturgeons start feeding on benthic crustaceans and insect larvae. This contradiction has apparently resulted from different research conditions. As a whole, a high plasticity of the feeding pattern in the early life stages of sturgeons has been found. Under favorable conditions, sturgeon larvae, upon a transition to the external feeding stage and later stages, feed mainly on zoobenthos; the species composition of food and size of consumed organisms changes in the wake of larvae growth. Zooplankton is constrained food in the case of a deficit of available benthic forms. The predominance of zoobenthos in the feeding during the early life stages of sturgeon, including the transition to the external feeding stage, is connected with (a) the bigger calorie count when compared with zooplankton and (b) a higher accessibility for larvae at the stage of mixed feeding, depending on their morphology and sensory-system development, with a delay of olfactory when compared to gustatory, seismic sensorial, tactile, and electroreception systems. [ABSTRACT FROM AUTHOR]

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Objective: The objective of this article is to examine the contextual factors impeding the growth and development of aquapreneurship in Cameroon. Research Design & Methods: The empirical study was conducted during November and December on a sample of 195 aquapreneurs in the Littoral, West, and Central regions of Cameroon. The study employed self-administered structured questionnaires and individual invitations were sent out to aquapreneurs in these regions. To compile the results, 150 completely filled-out questionnaires were used. Findings: Findings revealed that fish farmers faced several challenges including the high cost of constructing, filling, and managing ponds, the high rate of fish predators, fish death due to diseases, the high cost of feed, and the lack of financing, industries to manufacture quality fish feed, and space to expand fishponds. Implications & Recommendations: The study recommends all-encompassing measures by the government regarding awareness through education, the production of fingerlings at low cost to farmers, encouraging new entrants in fish feed manufacturing industries, and credit policies to accommodate aquapreneurs and improve incorporation into the globalised economy. [ABSTRACT FROM AUTHOR]

The chemical composition of diets is appointed as one responsible by different results of Lcarnitine supplementation in fish. This study determined the effects of digestible dietary protein (DP; 250 and 290 g kg-1) and crude fat (CF; 100 and 150 g kg-1) at levels of DL-carnitine supplementation (DLC; 0 and 1.0 g kg-1) in plant based-diets on growth and whole-body composition of Nile tilapia Oreochromis niloticus fingerlings (1.55 ± 0.03 g). Fish were hand-fed for 74 days, three times per day until apparent satiation, in a completely randomized experimental design, 2×2×2 factorial scheme (n = 3). There was no effect (P > 0.05) of DP, CF, and DLC, or interactions, on growth performance. There was a significant interaction between DP×CF; DP×DLC and DLC×CF on feed efficiency. There was interaction (P < 0.05) between CF×DLC on feed intake (DFI). The DLC supplementation in 100 g kg-1 CF diets increased DFI 5.6% more than fish fed with the same fat level without DLC. Whole-body protein decreased significantly due to DLC supplementation in fish fed with 150 g kg-1 CF diets. The level of DLC supplementation in Nile tilapia diets is variable and should consider the dietary CF levels, but not DP. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was performed to test the effects of glycyrrhetinic acid (GA) on growth and some gene expression of hepatic lipid metabolism in channel catfish (initial body weight, 3.5 ± 0.02 g) fed high-fat diets. Fish were fed the control diet, high-fat diet (HFD), and HFD supplemented with 0.4, 0.8, and 1.2 mg/kg GA in 15 tanks at a stocking density of 21 fish/tank. Fish fed HFD were significantly lower in body weight gain and specific growth rate but higher in feed intake and feed conversion ratio in comparison to the control. Supplement of GA at 1.2 mg/kg remarkably improved these parameters as compared to the control diet. High levels of cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), and low levels of high-density lipoprotein (HDL) in plasma were observed in fish fed HFD; the opposite was observed for fish fed HFD supplemented with GA. The transcription of fatty acid synthase (FAS), sterol regulatory element-binding protein-1 (SREBP1), liver X receptor alpha (LXRα), and hormone-sensitive lipase (HSL) was upregulated, while that of carnitine palmitoyltransferase I (CPT1), peroxisome proliferator-activated receptors alpha (PPARα), acyl-CoA oxidase (ACO), and microsomal triglyceride transfer protein (MTTP) mRNA expression were downregulated in fish fed HFD. The opposite was observed in fish fed HFD supplemented with GA as well as the control group. In conclusion, supplementing the HFD with GA at 1.2 mg/kg could improve the growth performance and lipid metabolism of channel catfish consuming HFD. [ABSTRACT FROM AUTHOR]

The present study investigated the growth performance, weight gain, feed conversion ratio, growth and survival rate of European catfish (Silurus glanis L.) fingerlings reared for one month in tanks with different colours. Four colours were used: light blue, white, green and black. The experimental unit was a flow-through system (0.8 L.min-1) consisting of eight tanks with water volume of 30L, continuous air supply and water heaters. Two hundred fish with an average weight of 1.85±0.62g were stocked in each tank. Results from the study demonstrated that the weight gain and the feed conversion ratio were poorly affected by the tested tank colours. Weight gain is slightly higher in groups A (blue) and B (white) than in groups C (green) and D (black). However, no significant difference was found in terms of weight gain among the experimental groups (p>0.05). Survival rate was the highest in group C (91%) followed by group D (88.5%). Thus, for rearing of European catfish fingerlings it is preferable to use dark coloured tanks, which resemble the natural habitat of the fish. [ABSTRACT FROM AUTHOR]

The article presents biotechnical measures for harvesting spawners and individuals of different ages of pikeperch from a natural reservoir and transporting pikeperch from fishing sites to a fish farms. The values of body weight, minimum allowable length and fatness of spawners and younger age groups of pikeperch are given. Comparative characteristics of fish-breeding and biological indicators of males and females with statistical processing of indicators are given. The characteristic of the production capabilities of wild pikeperch spawners during spawning, incubation of eggs and obtaining larvae is given. The article describes the biotechnical methods of conducting pikeperch spawning in spawning cages on nests in pond conditions of fish farms, incubation of eggs in "Amur" devices. Data on the culturing pikeperch juvenile in cages and the cultivation of fingerlings and two-year-old pikeperches in ponds are presented. The characteristic of fish-breeding and biological indicators of fingerling and two-year-old pikeperch cultured in a polyculture with cyprinid fish is given. The data of statistical analysis of indicators of weight final values, minimum allowable length and fatness of fingerlings and two-year-old pikeperches cultured in ponds for selection in the formed replacementbrood stock of pikeperch are presented. The dynamics of the main hydrochemical indicators of ponds is presented. The developed biotechnical standards for the formation of replacement-brood stock of pikeperch in the conditions of fish farms in the South of Kazakhstan are recommended. [ABSTRACT FROM AUTHOR]

This article presents the results of scientific research on the growing juveniles and the rearing fingerlings of pikeperch in cages. The conditions for growing larvae, juveniles, and fingerlings of pikeperch are described, and the dynamics of hydrochemical indicators of temperature, active reaction of the aquatic environment, oxygen content in water, and the state of the natural food supply in the experimental pond are presented. The data of a comparative analysis of fish-cultivation and biological indicators for three stages of growing larvae, juveniles and six stages of growing fingerlings of pikeperch in cages are presented. Prospective planting densities of fish planting material for pikeperch have been determined. The data on the use of live and artificial feed for feeding pikeperch are presented. [ABSTRACT FROM AUTHOR]

Background. Due to the growing need to establish new farming methods that improve management and food efficiency of African catfish, 225 Clarias gariepinus fingerlings (10.1± 0.01 g, average starting weight), were included in a study to evaluate three levels of CP (35.0,40.0, and 45.0%), with an equal protein-energy ratio (20.0 g protein / MJ), and the same absolute requirement of CP (2.8 g of GW / kg of live weight), in the productive performance of these animals. Methods. A simple classification method was utilized, with three treatments and three repetitions, and the Duncan significance test was run with 5% likelihood. The foods were added at 8.0, 7.0, and 6.2% of body weight, for 50 days. Results. The food supplied did not differ among the treatments. However, the greatest final weights and the best food conversions were observed after raising the levels of diet protein. The economic analysis showed higher ration costs, but also better profits when using the diet with the highest crude protein levels. Conclusions. Protein increase with equal absolute requirement (g CP/kg live weight) improves the productive performance of Clarias gariepinus. [ABSTRACT FROM AUTHOR]

Background. Due to the growing need to establish new farming methods that improve management and food efficiency of African catfish, 225 Clarias gariepinus fingerlings (10.1± 0.01 g, average starting weight), in order to evaluate three levels of CP (35.0, 40.0, and 45.0%), with an equal protein-energy ratio (20.0 g protein / MJ), and the same absolute requirement of CP (2.8 g of CP / kg of live weight), in the productive performance of these animals. Methods. A simple classification method was utilized, with three treatments and three repetitions, and Duncan significance test with a 5% likelihood. The foods were added at 8.0, 7.0, and 6.2% of body weight, for 50 days. Results. The food supplied did not differ among the treatments. However, the greatest final weights and the best food conversions were observed after raising the levels of diet protein. The economic analysis showed higher ration costs, but also better profits when using the diet with the highest crude protein levels. Conclusions. Protein increase with equal absolute requirement (g CP/kg live weight) improves the productive performance of Clarias gariepinus. [ABSTRACT FROM AUTHOR]