Growth Rate Of Fish Research Articles

Effects of Potassium Diformate (KDF) on Growth Performance and Some Physiological Parameters of Cultured Rainbow Trout (Oncorhynchus mykiss) in Commercial–Scaled Net Cages

This study was conducted to evaluate the feed utilization and protein effect ratios of combined and single diet administration of potassium di formate (KDF) in juvenile rainbow trout (Oncorhynchus mykiss). 600.000 trout fry were stocked as 50.000 in each cage and were fed 3 meals a day in the range of 25-80 grams and two meals a day up to 80-250 grams (until harvest time) and fed with commercial feeds until satiation. 3 kg/ton (T1), 5kg/ton (T2) and 7 kg/ton (T3) KDF were added to the diets and given to fish for 11 months. In the study, when the specific growth rates (SGR) of fish were compared, the results obtained in the T1, T2 and T3 groups were generally higher than in the control group. While no significant difference was found between T1 and T2 groups (p>0.05), there is a significant difference between T3, the other experimental groups and the control (p<0.05). In the study, a significant difference was found between the feed conversion rate (FCR of all groups, (p<0.05)). When the protein efficiency ratio (PER) was compared to the control group and the other groups, a significant difference was detected, while the same situation was found among the KDF supplemented groups (p<0.05). While the survival rate (SR) was significantly different between the control and experimental groups (p<0.05), there was no statistical difference between the experimental groups (p>0.05). The results of the study showed that the application of 7 kg/ton KDF can be considered a useful feed additive and a growth promoter for rainbow trout juveniles.

Corn-starch based formulated diet has growth and feed utilization efficiency advantages over trash fish diet for juvenile golden pompano Trachinotus ovatus

Until now, trash fish/low valued fish continues to be widely used in marine cage culture of pompano and many other carnivorous species in China and other Asian countries. This study is the first attempt to compare the performance of juvenile golden pompano Trachinotus ovatus fed trash fish or starch-based formulated diets. Three isonitrogenous (41 %) and isolipidic (11 %) diets containing 16, 22 or 28 % corn starch were prepared. Juvenile pompano (mean initial weight: 28.0 ± 0.3 g) were fed either formulated diets or trash fish on a equivalent dry-matter basis for 8 weeks. The survival rates were significantly higher in fish fed starch diets than fish fed trash fish (P < 0.05). Specific growth rate (SGR) of fish fed the 22 % and 28 % starch diets was significantly higher than fish fed 16 % starch diet and trash fish. Feed intake (FI) of fish fed trash fish was significantly higher than those fed formulated diets; however, feed efficiency (FE) and protein efficiency ratio (PER) of fish fed the formulated diets were higher than those fed trash fish, with the 22 % starch dietary group having a significantly higher FE value than fish fed trash fish. The whole-body energy retention (ER) of fish fed the diet containing 22 % starch had the highest ER, significantly higher than those fed 16 % starch and trash fish. The moisture in whole-body tissues of fish fed trash fish was significantly higher than the formulated dietary groups. On the other hand, whole-body protein and lipid contents of fish fed the 22 % starch diet was significantly higher than the other dietary treatments. The whole-body lipid level of fish fed trash fish was significantly lower than the other dietary groups. The body condition indices were significantly higher for fish fed formulated diets compared to those fed trash fish. The viscerosomatic index (VSI) was decreased with increasing dietary starch levels. Hexokinase (HK) activity significantly increased with increasing dietary starch levels, whereas pyruvate kinase (PK) activity had an opposite trend. The liver and muscle glycogen contents were generally increased with increasing dietary starch levels. In addition, the intestinal microbial communities of fish fed the formulated diets and trash fish was distinctly different. The results shown that formulated diet had advantages in performance and feed utilization efficiency over trash fish. Corn starch can be used as a suitable dietary carbohydrate. Evaluated on growth and FE, the optimal dietary corn starch level for T. ovatus is 22–24 % of diet.

EFFECT OF CARROT FLOUR (Daucus carota) TO INCREASE GROWTH AND COLOR BRIGHTNESS IN LEMON CICHLID FISH (Labidochromis caeruleus)

Ornamental fish is one of the main merchandise from the fisheries sector whose ability can generate income for the state and create income that can help the community's economy, especially those who are engaged in fisheries or cultivators. The most effective and dominant type of carotenoids for coloring fish is carotenoids derived from carrot flour because it is a natural source of beta carotene which can improve the quality and color brightness of ornamental fish such as lemon fish. The research design used a completely randomized design (CRD) with four treatments (carrot flour 0%, 5%, 10% and 15%) and three replications. The feed was tested on lemon cichlid fish measuring 3.7 - 4 cm and weighing 0.8 - 1 g which were kept in a 10 L jar. Parameters observed were growth rate, absolute weight, absolute length growth rate, survival rate, water quality and color increase in lemon fish. The results showed that the addition of 15% carrot flour had an effect on the color 9% brightness of lemon fish (Labidochromis caeruleus). The results showed that the addition of carrot flour for growth and color improvement was in the 15% carrot flour treatment, the absolute weight growth value was 0.73 g/fish, length 0.56 cm/fish, survival rate was 96.6%. The addition of carrot flour to the growth and color improvement can be concluded that a dose of 15% affects growth and can increase the color of lemon fish

Wild fish beat the heat

Wild animals can adapt to a wide range of temperatures. The ability to perform well in a constantly changing environment is called physiological plasticity. Physiological plasticity allows ectothermic animals, such as fishes, to maintain their metabolism even when the water that the fish is in heats up or cools down wildly. Fishes living in laboratories are less likely to have experienced temperature changes, so will their metabolism still perform well if there is a big temperature shift in their tank? Or have they lost their physiological plasticity because they have only experienced steady temperatures for more than 150 generations? Can living in steady environments affect a fish's behavior, metabolism or gene expression compared with living in a more turbulent environment? To study these questions, Rachael Morgan and colleagues from the Norwegian University of Science and Technology and the University of Greenwich, UK, compared the physiological plasticity of two populations of zebrafish: a wild population collected from India and a population raised in the lab. They aimed to understand whether living in a stable environment can change a fish's ability to perform when there is a big change in temperature.The researchers collected 300 zebrafish from the two populations and exposed each group to a variety of temperatures (from 10 to 38°C) for 1 month. They then measured the fish's swimming ability, escape response, growth rate, metabolic rate and gene expression and compared the measurements of the two groups to learn whether the lab-raised group had more difficulty in adapting to large temperature shifts than the wild group because they have less physiological plasticity.Sure enough, the lab-raised fish were less able to adjust to temperature change than the fish that had come from India. The lab-raised zebrafish were slower swimmers than wild zebrafish at all temperatures, and when escaping, lab-raised zebrafish responded more slowly than wild zebrafish, especially when in colder temperatures. In addition, the lab-raised zebrafish grew faster than the wild zebrafish, likely because domesticated animals are selected for faster growth rates. When comparing metabolism between the groups, the researchers measured the range of temperatures at which the fish could reach their maximum metabolic rates. They found that lab-raised fish could only reach their maximum metabolic rate in water temperatures between 26 and 36°C, but wild fish could reach their maximum metabolic rate over a much broader temperature range (21–38°C). Gene expression was also different among the two groups. The lab fish had greater levels of proteins that deal with stress compared with the wild fish. Interestingly, very cold temperatures were especially difficult for both groups, which may suggest that physiological plasticity is limited at these extreme temperatures.This study tells us that lab domestication affects the ability of animals to adjust to changes in their environment across several biological levels, from behaviour to gene expression. With this knowledge, scientists should take into account that domestication can change animals’ responses to an experiment when choosing study animals. Morgan and colleagues also suggest that there may be a trade-off between high levels of physiological plasticity and growth rates and warn that domestication can quickly lead to a loss of physiological plasticity.

Linking variation in planktonic primary production to coral reef fish growth and condition.

Within low-nutrient tropical oceans, islands and atolls with higher primary production support higher fish biomass and reef organism abundance. External energy subsidies can be delivered onto reefs via a range of physical mechanisms. However, the influence of spatial variation in primary production on reef fish growth and condition is largely unknown. It is not yet clear how energy subsidies interact with reef depth and slope. Here we test the hypothesis that with increased proximity to deep-water oceanic nutrient sources, or at sites with shallower reef slopes, parameters of fish growth and condition will be higher. Contrary to expectations, we found no association between fish growth rate and sites with higher mean chlorophyll-a values. There were no differences in fish δ15N or δ13C values between depths. The relationship between fish condition and primary production was influenced by depth, driven by increased fish condition at shallow depths within a primary production ‘hotspot’ site. Carbon δ13C was depleted with increasing primary production, and interacted with reef slope. Our results indicate that variable primary production did not influence growth rates in planktivorous Chromis fieldi within 10–17.5 m depth, but show site-specific variation in reef physical characteristics influencing fish carbon isotopic composition.

Effects of partial replacement of fish meal with porcine meat meal on growth performance, antioxidant status, intestinal morphology, gut microflora and immune response of juvenile golden pompano (Trachinotus ovatus)

This study was conducted to investigate the effects of partial replacement of fish meal (FM) with porcine meat meal (PMM) on growth performance, plasma antioxidant parameters, intestine morphological parameters, gut microflora and expression of intestinal Nrf2 and Nf-κB signaling pathway of juvenile golden pompano. Fish were fed with six experimental diets (0 (PC), 10% (P10), 20% (P20), 30% (P30), 40% (P40) and 50% (P50) replacement levels) for 8-weeks. The percent weight gain and specific growth rate in fish fed with P40 and P50 diets were significantly lower than those of the control group (P < 0.05). Compared with the control group, the plasma antioxidant indexes including the activities of superoxide dismutase, catalase, glutathione peroxidase, total antioxidant capacity and malondialdehyde content in fish fed with P30, P40 and P50 diets were significantly affected (P < 0.05). With dietary replacement of FM with PMM increasing 0 to 30%, the relative expressions of IL-10, TGF-β, Nrf2, SOD, Cu/Zn-SOD and GSH-Px were significantly down-regulated, while the relative expressions of NF-κB, TNF-α, IL-1β and IL-8 were significantly up-regulated (P < 0.05). Villus heights and crypt depths of proximal and mid intestine were significantly affected with dietary replacement of FM with PMM increasing 0 to 40% (P < 0.05). The structure of the intestinal microbial flora showed that the relative abundances of beneficial bacteria decreased, and the relative abundances of pathogenic bacteria increased in fish fed with P50 diet compared with the control group. In conclusion, replacing FM with PMM up to 30% had no significant impact on growth performance and feed utilization of golden pompano. However, 30% replacements of FM with PMM exerted adverse effects on antioxidant capacity and immune response of fish. In addition, replacement of a high proportion of FM with PMM negatively affect the gut microflora of fish.

Assessing the feasibility of particle size reduction and fermentation as pre-processing techniques to utilize enzyme-treated feather meal in zero fish meal diets for Nile tilapia (Oreochromis niloticus)

In this study, a growth trial and digestibility assays were conducted to evaluate the applicability of particle size reduction and fermentation as pre-processing techniques to treat enzyme-treated feather meal (ETF) for zero fish meal diet of Nile tilapia (Oreochromis niloticus). According to particle size, ETF was mechanically sieved and separated into three different categories (un-sieved (EFM), particles < 850 µ (EFM850), particles < 425 µ (EFM425)) while a portion of each category was separately fermented for 24 h using Baker’s yeast to produce fermented ingredients, un-sieved (FEFM), fermented 850 µ (FEFM850) and fermented 425 µ (FEFM425). Seven isoproteic and isoenergetic diets were prepared including a control diet with 10 % fishmeal. The fishmeal component of the control diet was completely replaced by one of the six types of EFM in test diets. Sex-reversed male Nile tilapia (~ 6 g initial weight) fingerlings were stocked (20 fish per tank) in circular concrete tanks (200 L). Each treatment with three replicates was randomly allocated into 21 tanks using a complete randomized design. Fish were hand-fed twice a day to near satiety for 56 days. In-vivo digestibility study and in-vitro protein hydrolysis assays of six EFM types were evaluated by mixing 30 % of test ingredients and 70 % of reference diet having 0.5 % of chromic oxide. In vitro assay was performed by using crude enzymes extracted from Nile tilapia. Results of the growth trial revealed that the final mean weight, daily weight gain, and % specific growth rate of fish fed EFM425 and FEFM were significantly higher than that of other treatments (p < 0.05) while FEFM425 showed significantly lowest growth performances. Feed intake of fish in FEFM treatment was significantly higher than that of control. The effects of different dietary treatments on survival rate and feed utilization efficiency were not statistically different (p > 0.05). The highest protein (77 %) and dry matter (68 %) digestibility were observed for EFM425 and FEFM while the dry matter digestibility positively correlated to the daily weight gain (R2 = 0.80). Based on growth performance, feed utilization efficiencies, and digestibility, EFM425 and FEFM were best among tested treatments. But in practice, particle size reduction is more convenient than fermentation. It was concluded that fish meal components of Nile tilapia diets can be replaced by EFM by reducing their particle size up to 425 µ.

Dietary lipid and protein levels influence the growth and feed utilisation of large yellowtail kingfish (Seriola lalandi) at summer water temperatures

Yellowtail Kingfish (Seriola lalandi; YTK) have a fast growth rate, and as a result, a high energy demand that could be satisfied by dietary lipids. The aim of this experiment was to determine the optimum dietary protein and lipid levels for large YTK maintained during a summer growing season. In this 84-day experiment (2 × 3 factorial design), the growth, feed utilisation and health of YTK (initial weight 2.13 ± 0.02 kg, mean ± SE) fed two nominal lipid levels 25% crude lipid (CL) (20 MJ kg−1 energy) and 30% CL (21 MJ kg−1 energy) and three nominal crude protein (CP) levels (40, 44 and 48%) were investigated. The specific growth rate of fish was significantly affected by the interaction between dietary CP and CL level. The results indicate that fish fed the 25% CL diets grew better than those fed the 30% CL diets. The interaction effect was primarily driven by the significant increase in growth for fish fed diet 1 (40% CP × 25% CL) and diet 2 (44% CP × 25% CL) compared to their respective 30% CL diets, diet 4 (40% CP × 30% CL) and diet 5 (44% CP × 30% CL). The growth of fish fed diet 3 (48% CP × 25% CL) and diet 6 (48% CP× 30% CL) was not significantly different. Feed conversion ratio (FCR) was not significantly influenced by diet however, the fish fed the 25% CL diet series and 40% protein series consumed the most feed. Fish fed the 25% CL series increased their feed intake with decreasing dietary CP level, to potentially compensate for reduced dietary protein. In contrast, fish fed the 30% CL series did not. Crude protein intake was higher when fish were fed the 48% CP diets and was reduced when fed the 40% and 44% CP diets. This response was more pronounced in the 30% CL diet series. There were no negative health effects noted during the study for various analyses including blood biochemistry and haematology, and gastrointestinal tract morphology. Numerically, the highest final weight, biomass gain, SGR, and FCR were consistently observed in the fish fed diet 2, however these were not significantly different to diet 1. Based on the combined results for 2.1–3.5 kg YTK raised during summer, the diet should contain at least 42.9% CP and 25.3% CL (equivalent to diet 2) corresponding to 19.9 MJ kg−1 GE diet with and a CP: GE ratio of 21.6 g MJ−1. In terms of actual protein and energy intake required this corresponds to 5.2 g CP−1 kg BW−1 d−1 (4.5 g DP−1 kg BW−1 d−1) and 242 KJ−1 GE kg BW−1 d−1 (207 KJ−1 DE kg BW−1 d−1) which appears to be optimal. We do not recommend diet lipid levels of approximately 30% over summer periods, as demonstrated in this experiment.

Dietary combination of maggot and commercial feed enhance the growth rate and feed conversion ratio of snakehead fish (Channa striata)

Snakehead fish (Channa striata) is a carnivorous freshwater fish commodity that has high economic value. However, this cultivation takes a long period due to its poor growth rate. Maggot has been proposed as a possible alternative to fish feed because it is less expensive and has nutritional value. This study aimed to determine the effect of the dietary combination of maggot and pellets on the growth rate and feed conversion ratio of snakehead fish. This study used a completely randomized design (CRD) with five treatments and four replications. The treatments were P0: 100% pellet, P1: 100% maggot, P2: 75% pellets and 25% maggot, P3: 50% pellets and 50% maggot, P4: 25% pellets and 75% maggot. The result showed a combination of pellet feed and maggot feed had a significant improvement (p<0.05) on the growth rate of snakehead fish. However, there were no significant differences in the feed conversion ratio (p>0.05). The treatment of 75% pellet feed and 25% maggot feed (P2) generated the highest growth rate of 0.154 g/day and the lowest feed conversion ratio of 3.121. It can be concluded that the combination of maggot and pellet experienced better growth performance and feed conversion ratio of snakehead fish.

The dependence of the growth of carp yearlings (cyprinus carpio) on the density of planting in cages in the conditions of the Karkidon reservoir of Uzbekistan

The effect of stocking density on the growth of common carp (Cyprinus carpio) in cages was studied. Common carp yearlings (22 g) from the pond hatchery were stocked at 30, 60, 90 ind./m3 (in triplicate). Fish were fed with “Huvalon siliao” aquafeed (Uzbekistan) (35% protein) with ratio 3% of the fish biomass per day. The growth rates of fish in different variants, both in absolute terms and in relative terms (growth rate, specific growth rate), were the same. Carp yearlings were brought from a pond fish nursery and planted evenly in cages. A week was allo-cated as a period of adaptation of fish to the conditions of cages, during this period they were fed at the rate of 3% of the fish biomass. At the beginning of the experiment (May 10) the fish were planted in 30, 60, 90 yearlings of carp in a cage (in triple repetition), the average individual weight of carp (w1, g) in each of the nine cages was 22 g.

The effect of different stocking densities on specific growth rate and survival rate of striped snakehead (Channa striata) culture in bucket system

Striped snakehead culture in bucket system with high stock rate at a good living environment, and also adequate feeding can lead to the maximization of production. However, if the stocking density is too high, it can inhibit the survival and growth of fish caused by competition for space, feed and oxygen as well as increased metabolic waste. The purpose of this study was to determine the effect of different stocking densities on the specific growth and survival rate of snakehead fish (Channa striata) in buckets. This study used is Completely Randomized Design consisting of 5 treatments and 4 replications, namely P0 (1 fish/L), P1 (2 fish/L), P2 (3 fish/L), P3 (4 fish/L) and P4 (5 fish/L). The ANOVA results showed that the difference in stocking density had a significant effect (P<0.05) on the growth rate of specific weight and length as well as the survival rate of fish. DMRT showed that P1 was the highest result for specific weight and length growth rates (0.90%/day and 0.80%/day) and the lowest at P4 (0.62%/day and 0.40 %/day). In addition, the highest of survival rate are also shown at P1 (95.42%) and the lowest at P4 (32.75 %).

Effect of dietary levels of folic acid on growth performance, blood biochemistry, antioxidant capacity, and immunity of juvenile largemouth bass, Micropterus salmoides

AbstractTo obtain the optimal requirement of dietary folic acid (FA) in feed of juvenile largemouth bass, Micropterus salmoides, five experimental diets were prepared with 0, 0.5, 1.5, 4.5, and 13.5 mg/kg of supplemental FA in the basal practical diet (measured FA value &lt;0.18 mg/kg in the basal diet) and fed to juvenile largemouth bass with an initial body weight of (14.49 ± 0.06) g for 7 weeks. The results showed that the weight gain rate and specific growth rate of the experimental fish in each FA supplementation group were higher than those in the control group to varying degrees and reached maximum values at 1.5 mg/kg in the experimental group, which were significantly higher than those in the FA‐free group; the increase in the addition of FA to the diet significantly reduced the visceral to body ratio (visceral somatic index), liver to body ratio, and relative intestine weight. The addition of ≥0.5 mg/kg FA to the feed significantly increased the whole fish protein content. The hemoglobin content and hematocrit of whole blood cells were significantly increased in the fish group supplemented with 0.5–1.5 mg/kg FA, and the addition of 0.5 mg/kg FA significantly increased the number of red blood cells. Plasma total protein and albumin levels increased and then decreased with the addition of FA, reaching a maximum at 1.5 mg/kg, and differed significantly from the FA‐free group. The addition of 0.5 mg/kg and more of FA significantly decreased plasma alanine transaminase (GPT) activity and improved liver GPT activity, the addition of 0.5 mg/kg and more of FA significantly decreased serum malonaldehyde activity, 0.5 mg/kg of FA significantly increased total hepatic antioxidant capacity, 1.5 mg/kg of FA significantly increased hepatic catalase and head kidney lysozyme activity. The addition of 0.5 mg/kg and above of FA significantly reduced liver glycogen content. In conclusion, the addition of FA to the diet significantly improved the growth performance, hematopoiesis, metabolism of protein and carbohydrate, antioxidant capacity of the liver, and protected liver health of juvenile largemouth bass. Regression analysis based on growth performance showed that the optimal amount of FA in the feed of juvenile largemouth bass was 1.42–1.46 mg/kg.

Effects of Stocking Larger-Sized Fish on Water Quality, Growth Performance, and the Economic Yield of Nile Tilapia (Oreochromis niloticus L.) in Floating Cages

Earlier research has mostly focused on the impacts of stocking density on fish growth, yield, and survival rate; however, knowledge of the effects of stocking larger-sized fish, particularly Nile Tilapia, is lacking. This type of research is critically important for increasing food security, achieving sustainable goals, and facing the challenges of climate change in the near future. Therefore, we investigated the effects of initial stocking body sizes of Nile Tilapia (Oreochromis niloticus) on water quality, growth performance, and economic yield in tropical riverine cages for 120 days in two culture cycles. Nile Tilapia of three different body sizes (34.06 ± 0.22 g, 10.98 ± 0.09 g, and 5.47 ± 0.04 for the first cycle and 33.85 ± 0.01 g, 11.07 ± 0.05 g, and 5.38 ± 0.06 g for the second cycle, indicated as T1, T2, and T3) were stocked in the culture treatments where unique stocking density and feed rations were maintained. The results revealed that water quality parameters did not differ significantly (p &gt; 0.5) and were within a suitable range for Nile Tilapia culture. Treatments with larger-sized fish demonstrated a higher growth performance. The stocking fish size of 34.14–34.71 g was found to be the best among the three treatments regarding growth performance and economic return. As a result, except for T1 and T2 at a rural site and T1 at a semi-urban site, all of the treatments had negative allometry (b &lt; 3.0), indicating that larger-sized fish and the rural site of the river are more suitable for cage culture. The rural site was found to be more suitable, possibly due to less variation of water parameters, more natural foods, and less pollution. The cages with larger-sized fish stocked had a higher net present value (NPV); internal rate of return (IRR); benefit–cost ratio (BCR); and rate on return (ROI), indicating that cage culture with larger-sized fish stocked is economically viable in the riverine system. Therefore, stocking the larger-sized fish (T1) and rural site are more suitable for cage culture.

Current state and trends of the use of vegetable feedstock in aquaculture feeds (review)

Rising prices of traditional feedstock for feed preparation (fish meal and oil) is a problem for aquaculture enterprises. Their replacement with inexpensive components of vegetable origin is the way for solving the problem. The aim of the study is to generalize and analyze scientific data on using new types of vegetable feedstock in aquaculture feeds, on technologies of their preparation and use, influence on feed quality. Selection and systematic review of scientific literature on the topic of the study for the period of 2017-2022 has been carried out. The derivatives of land agricultural plant products such as oilseed meal, protein concentrates, gluten and food industry wastes are the main types of vegetable feedstock for feed preparation in aquaculture. Currently, vegetable oils are the best variants for replacing fish oil in fish diets. Partial or complete replacement of fishmeal and oil with new types of vegetable feedstock is possible and does not lead to deterioration of fish health and growth rate when these components are included in the diet at recommended doses. Such a replacement is economically advantageous. But there are negative effects in the use of vegetable feedstock, such as the presence of anti-nutritional factors that limit its use in aquaculture. The development of recipes of cost-effective fish feeds in which fish meal and oil are completely replaced by vegetable components is a research priority for the development of intensive aquaculture.

Artificial Neural Network and Near Infrared Light in Water pH and Total Ammonia Nitrogen Prediction

Water quality plays an important role in aquaculture. The operation of a freshwater aquaculture fish farming is highly dependent on the ability to understand, monitor, and control the physical and chemical constituents of the water. pH and total ammonia nitrogen (TAN) levels are two critical water quality parameters that affect fish growth rate and health. However, pH and TAN levels are affected by uncontrollable factorse.g.weather, temperature, and biological processes occurring in the water. Therefore, it is important to monitor changes in pH and TAN levels frequently to maintain optimal conditions for freshwater habitats. Near infrared spectroscopy (NIR) has been extensively investigated as an alternative measurement approach for rapid quality control without sample preparation. Therefore, this research aims to evaluate the feasibility of machine learning combined with NIR light in predicting the water pH and TAN values of a fish farming system. The proposed system contains three main components i.e.a multi-wavelength light emitting diode (LED), a light sensing element, and a machine learning model i.e.artificial neural network (ANN). First, the transmitted NIR light with different wavelengths of water samples was measured using the proposed system. Then, the actual pH and TAN values of the water samples were quantified using conventional methods. Next, ANN was used to correlate the measured NIR transmittance with the pH and TAN values. The results show that ANN with four hidden neurons achieved the best prediction performance with a mean square error (MSE) of 0.1466 and 0.3136 and a correlation coefficient (R) of 0.8398 and 0.9560 for the pH and TAN predictions, respectively. These results show that ANNcoupled with NIR light can be promisingly developed for in situ water quality prediction without sample preparation.

Survival rate, growth and condition index of tank-raised Clarias gariepinus under different salinities

The study evaluated varying levels of salinity on survival, growth and condition index of tank raised Clarias gariepinus for ten weeks. A total of 120 healthy C. gariepinus fingerlings having a bulk weight and average length of 131.73 ± 0.85 g and 5.06 ± 0.24 cm respectively were procured from the hatchery complex of University of Calabar fish farm and used for the study. Sea water was collected from Ibeno Beach and diluted with borehole water to obtain various salinity concentrations of ≤1, ≤5, ≤10 and ≤15 ppt. This represented four treatments(Tanks A to D) and each treatment had three replicates. Evaluation of growth indices and culture water parameters followed standard procedure. Results revealed significant (p &lt; 0.05) differences with regards to food intake in the treatment Tanks A (≤1ppt), B (≤5ppt), C (≤10ppt) and D (≤15ppt). Food conversion efficiency (FCE), ratio (FCR) and protein efficiency ratio (PER) were significantly different (p &lt; 0.05). Body weight gain were observed to be higher in Tank A with a value of 75.83± 0.07g/kg and a total length of 11.13 ±0.38cm and the lowest weight gain was recorded in Tank D with a value of 43.56 ± 0.76g/kg and a mean total length of 6.67± 0.43cm. There were significant differences (p &lt; 0.05) in the final condition factor (K) of the fish. Hence, it could be established that C. gariepinus fingerlings can survive and be reared in 5ppt saline water without any adverse effect on growth. At salinity level above 5ppt, fish growth rate may be slow.&#x0D; Keywords: Survival rate, Growth, Clarias gariepinus, Salinity, Physicochemical parameters

Cockroach (Periplaneta Americana) as fishmeal replacer in diets of African catfish (Clarias gariepinus) Juveniles

The utilization of insects as feed has witnessed dramatic inclusion in livestock and aquaculture diets. The farming of cockroach (Periplaneta americana) is gaining acceptance among industries. However, research on its use in livestock and fish nutrition is scanty. This study aimed at investigating the growth of Clarias gariepinus juveniles fed cockroach insect meal (CIM) as fishmeal (FM) replacer. One hundred and fifty Clarias gariepinus juveniles (6.29 ± 0.06 g) were stocked at 10 fish/tank/replicate and fed 40% crude protein diets formulated thus: Diet 1 (0% CIM; control), Diet 2 (25% CIM), Diet 3 (50% CIM), Diet 4 (75% CIM) and Diet 5 (100% CIM). Fish were fed at 5% of their body weight twice daily for 56-day experimental period. The results showed that final weight, mean weight gain, specific growth rate, protein efficiency and food conversion ratios of fish fed 25 and 50% insect meal-based diets were not significantly different (p&gt;0.05) from those treated with the control diet. Survival rates were not significantly different in all dietary treatments. Quadratic regression analysis revealed that insect meal can be used at up to 58% inclusion level in diets of C. gariepinus juveniles for optimal growth.&#x0D; Keywords: Amino acid, Blattodea, fish-nutrition, growth performance, C. gariepinus

Preliminary study on the utilization of aqueous bark extracts of Khaya ivorensis in diets of Clarias gariepinus fingerlings

Mortality of fish seeds is recognised as one of the major factors responsible for serious economic losses in fish culture business. A preliminary investigation on the effects of aqueous extracts of dried African mahogany, Khaya ivorensis bark on the growth, survival, haematology and histology of Clarias gariepinus fingerlings was conducted. A total of 135 C. gariepinus fingerlings (1.41±0.03 g/fish) were randomly allocated into three treatments, T1 (Control), T2 and T3, and fed with three different diets (40% CP) D1, D2 and D3 containing 0g/L, 25g/L and 50g/L aqueous extracts of K. ivorensis bark respectively. The experimental fish were fed ad-libitum for a period of 28 days in rectangular plastic containers (15x25x30cm3 ) and water exchange was done daily. Experimental data were analyzed for statistical differences in the growth, survival indices, haematology and histology of experimental fishes using analysis of variance (ANOVA). There was no significant difference (p&gt;0.05) in mean weight gain of Control (2.91±0.68g) and T2 (2.20±0.20g) but T3 (1.79±0.39g) was significantly low. There was a significant difference in the survival (S) of experimental fish with the S (%) values of 73.67±13.50, 68.67±16.50 and 57.00±10.00 for T2, T3 and control respectively, no significant different in the feed conversion ratio (p&gt;0.05) in the experimental groups. The haematological characteristics of all experimental fish were not significantly different, though the packed cell volume, PCV (%), haemoglobin count, HB (g/dl) and red blood cell, RBC (million/mm) were in the order T2˃T3˃Control having mean values of 22.71±4.5˃21.67±5.1˃19.67±1.53 (PCV); 22.67±4.51˃2.67±6.51˃19.67±1.53 (HB) and 2.09±0.47&gt;1.99±0.57&gt;1.73±0.13 (RBC) for T2, T3 and control respectively. The white blood cell, (No/mm) was highest in T1 (4.03±0.25) and least in T3 (3.67±1.35). Although there was no degeneration, the histological characteristics of liver of the experimental fish ranged from moderately diffused to fewer hepatocytes when compared to the normal liver, of the control. It is therefore concluded that Khaya ivorensis bark can be included in the diet of Clarias gariepinus fingerlings at 25g/L aqueous extract for good growth and high survival rates of fish under culture&#x0D; Keywords: Medicinal herbs, Extracts, African catfish, Fish culture

Prey selection and growth in 0+ Eurasian perch Perca fluviatilis L. in littoral zones of seven temperate lakes

AbstractWe studied the relationships between the planktonic food base and feeding patterns of juvenile mid‐summer/early autumn Eurasian perch Perca fluviatilis L., a common predatory freshwater fish in large parts of Europe and Asia. The feeding of 0+ perch was studied during summer and autumn in littoral habitats of seven lakes with different environmental conditions – four Latvian (Auciema, Riebinu, Vārzgūnes, Laukezers) and three Estonian (Kaiavere, Prossa and Akste) lakes. Simultaneously, the abundance, biomass and structure of zooplankton communities were examined. We focused on the littoral areas because many studies in lakes suggest that littoral habitats are particularly important for 0+ fish growth and survival. We were interested in the question: can the diet and growth of 0+ perch be explained by zooplankton community structure? We also presumed that if the amount of zooplankton is low, more benthic invertebrates will be consumed by 0+ perch. Opposite to expectations, we found that zooplankton always counted for over 90% of diet biomass in perch. There were also clear correlations between the zooplankton biomass in a given lake, the zooplankton biomass in 0+ perch stomachs, and the fish growth rate. The study also suggested that nutrient enrichment can positively impact the 0+ perch feeding conditions in lakes.

Growth Performance of Pangasius sp Fed Different Types of Diets Formulated from Varieties Fish Meal Sources

Pangasius sp is an introductory species that is widely distributed in freshwater regions in Indonesia since the 1990s and it was initiatively reared at the beginning of 2011 using a floating net cage in Lake Ngade, Ternate. Even though it has benefited economically, there is still a lack of information on its biological and ecological aspects. Growth and survival rate are two main factors that should be known to develop Pangasius aquaculture. The study aims to understand the growth and survival rate of Pangasius by mixing different fish meals into dietary. 120 Pangasius fingerlings were placed into 12 tanks. Diet was formulated using Pearson’s square method. Three different protein fish meal sources were mixed into feed formulation namely flying fish meal, Nile meal, and eel meal. Commercial feed was used as control. Filling Randomized Design (FRD) was applied with the experimental set-up of the treatments. The results show that feed stability in water ranges from 2'23" to 3'47" while feed durability ranges from 2'09" to 2'35". The survival rate of Pangasius is almost 100% except for treatment C. Growth rates vary among treatments which is the highest found in treatment A (16.42%) followed by treatment B (15.85%), D (15.57%), and C (7.00%) respectively. Nile fish meal is also significantly affected (P0.05) by the Specific Growth Rate (SGR) of fish. Nutrition ingredients and water quality parameters are conducive to maintaining the fish's life. All in all, different fish meal sources in the formulated diet are significantly supporting Pangasius growth.