Fat Content Of Fish Research Articles

Annual Variation in Proximate Chemical Composition of Fish Sold in Ludhiana Market: Punjab, India

A study was carried out to investigate the nutritional composition of four different fish species (Wallago attu, Labeo rohita, Pangasianodon hypophthalmus, and Rastrelliger kanagurta) sourced from the inland and marine sector comprising both culture and capture fisheries marketed in Ludhiana fish market from September 2021 to August 2022, encompassing four distinct seasons: post-monsoon, winter, pre-monsoon, and monsoon. The proximate parameters including protein, lipid, carbohydrate, ash and moisture content were analysed following the standard methods. The moisture content across the four species ranged from 72.48% to 81.08% in selected fish. Lowest moisture content was recorded during the pre-monsoon season, contrasting with their highest levels during the monsoon season. Protein levels ranged from 9.72% to 18.36% across different seasons. Specifically, P. hypophthalmus displayed the lowest protein content (9.72±0.18%), while R. kanagurta exhibited the highest (18.36±0.18). W. attu, L. rohita, P. hypophthalmus, and R. kanagurta exhibited their lowest lipid content in flesh during the monsoon season, measuring at 0.69%, 1.59%, 9.33%, and 2.47%, respectively, contrasting with their highest levels during the winter season at 1.07%, 2.05%, 11.04%, and 4.05%, respectively. Across different seasons, carbohydrate content varied from 0.23% to 2.04%. R. kanagurta exhibited the lowest carbohydrate values; while L. rohita displayed the highest. Across different species, ash content varied from 1.62% to 4.34%, with the lowest observed in P. hypophthalmus and the highest in W. attu. Overall in fish muscle, water content reached its peak levels while muscle protein content decreased during the monsoon. The decline in protein and the rise in water content of the muscle were attributed to gonadal development and maturation, which depleted muscle protein reserves during the monsoon season. Inverse relationship between moisture and fat content in fish were observed, suggesting that fatty fish typically exhibit relatively lower moisture content. Lower levels of carbohydrate content are found in the total proximate composition of fish muscle, indicating that most of the glycogen in freshwater fish does not significantly contribute to body reserves.

Effect of Beta vulgaris L. as feed ingredient on muscle growth, nutritional factors, and quality of common carp, Cyprinus carpio.

The purpose of this study was to evaluate the utilization of Beta vulgaris powder as feed ingredient in the diet of Cyprinus carpio for a period of 56 days. Common carp fry with an average weight of 20 ± 0.2 g were fed using the diet containing B. vulgaris leaves with different concentrations. Fry of Cyprinus carpio were equally distributed in four feeding groups having three replicates each. The study was conducted indoors, in FRP tanks, and aeration was provided to individual rearing units, and it was a flow-through system. The basal diet was replaced at 0.5%, 1%, and 2% with B. vulgaris powder. The basal diet without B. vulgaris powder (0%) served as control (T1). Significantly higher feed conversion ratio, protein efficiency ratio, and fat and protein indices were recorded in fish fed with B. vulgaris powder in treatments. Different feeding groups showed greater acceptability of B. vulgaris powder mixed diet without any adverse behavioral response. The protein and fat average percentages were 43.32 and 10.79 g, when fish reached commercial weight (48.02, 11.85 g) after 56 days for treatment 2%. After fish feeding with the B. vulgaris, for treatment 2% lower moisture than the control was recorded. The carp fish diet containing 1% B. vulgaris leaf powder caused a significant decrease in the fish fat content. It can be concluded that the diet containing 2% B. vulgaris leaf powder in the common carp led to better growth performance. The presence of B. vulgaris leaves in the fish diet increased the fillet protein and ash content.

Boiling for 15 minutes improves nutrient profiles in fishes included in the diets of dialysis patients.

Little is known about the effects of boiling on nutrient levels in fishes that have a relatively high phosphorus-to-protein ratio (PPR), which are important sources of omega-3 polyunsaturated fatty acids. We hypothesized that the beneficial effects of boiling for a shorter duration (15 min) on nutrient contents in fishes were similar to those of boiling for a longer duration (30 min), which has been shown to decrease the PPR in meat. The protein, fat, and phosphorus contents and the PPR of three cooked fish species and their corresponding fish broths were chemically analyzed. The effects of boiling on changes in protein, fat, phosphorus, and the PPR was examined by comparing fish that were prepared with usual cooking methods (no boiling), boiled for 15 min, and boiled for 30 min. The nutrients in fish broths that were boiled for 15 min were also compared with those boiled for 30 min. There were no significant differences in the changes in phosphorus, PPR, protein, and fat content in fish and fish broths prepared with the two boiling methods. In the fish boiled for 15 min, the phosphorus content was 24% lower (p= 0.001), and the PPR was 20% lower (p= 0.04) than those in nonboiled fish. Additionally, boiling for 30 min reduced the phosphorus content by 31% (p= 0.001), and the PPR by 27% (p= 0.04) compared to nonboiled fish, but the protein and fat contents were unchanged after both 15 and 30 min of boiling. The 15- and 30-min boiling methods resulted in a similar reduction in phosphorus and the PPR in fish, with minimal effects on protein and fat. A shorter duration of boiling is recommended to achieve better nutrient profiles in fishes consumed by dialysis patients.

Transgenic red carp (Cyprinus carpio) with LcMSTN1 propeptide: Enhanced growth and unchanged muscle fat content

Growth and meat quality are concerned issues in aquaculture. The inhibition of MSTN can lead to significant muscle proliferation in mammals, as well as a decrease in muscle fat content. In fish, the effect of MSTN inhibition on muscle fat content is ambiguous. In this study, we constructed transgenic red carp with Larimichthys crocea MSTN1 propeptide (LcMSTN1 propeptide) to study how the inhibition of MSTN1 affects the growth and muscle fat content in fish. Southern Blotting showed that LcMSTN1 propeptide was integrated into the red carp genome. In muscle tissue, the expression of MSTN1 propeptide in transgenic red carp was significantly higher than that of non-transgenic red carp (P < 0.001). The mRNA levels of growth-related genes, MyoD, MyoG and MyHC, in the muscle tissue of transgenic red carp were also significantly higher than those in non-transgenic red carp (P < 0.01). However, there was no significant difference in both muscle fat content and the mRNA levels of lipid metabolism-related genes FAS and LPL between transgenic and non-transgenic red carps. Microscopical observation showed that the muscle fiber diameter in transgenic red carp was significantly larger than that of non-transgenic red carp, implying hypertrophy of muscle fibers. These results indicate that LcMSTN1 propeptide can promote the muscle growth, and does not affect muscle fat content in transgenic red carp, which is different from mammals.

Salmonids as Natural Functional Food Rich in Omega-3 PUFA

Salmonids are valuable fish in the human diet due to their high content of bioactive omega-3 very long-chain polyunsaturated fatty acid (VLC PUFA). The aim of this study was to assess the omega-3 VLC PUFA content in selected salmonid fish present on the food market regarding whether they were farm-raised or wild. It was assumed that farm-raised fish, by eating well-balanced feed enriched with omega-3 PUFA, might contain omega-3 VLC PUFA in levels similar to that of wild fish. Fat content, fatty acid composition and omega-3 VLC PUFA content in fish fillets were measured. Farm-raised salmon from Norway, wild Baltic salmon, farm-raised rainbow trout and brown trout were bought from a food market whereas wild trout (rainbow and brown) were caught alive. The fat content in fish ranged from 3.3 to 8.0 g/100 g of fillet. It was confirmed that although wild salmonid fish contain 10–25% more omega-3 VLC PUFA in lipid fraction, the farm-raised ones, due to the 60–100% higher fat content, are an equally rich source of these desirable fatty acids in the human diet. One serving (130 g) of salmonid fish fillets might provide a significant dose of omega-3 VLC PUFA, from 1.2 to 2.5 g. Thus, due to very high content of bioactive fatty acids eicosapentaenoic (EPA), docosapentaenoic (DPA) and docosahexaenoic (DHA) in their meat, salmonid fish currently present on the food market, both sea and freshwater as well as wild and farm-raised, should be considered as natural functional food.

Effects of Partial Substitution of Fishmeal by Crustacean (Callianassa) Meal on the Growth Performance, Feed Efficiency and Survival Rate of Nile Tilapia (Oreochromis niloticus)

The effect of substituting fishmeal with crustacean (Callianassa) meal in the diets of mixed sex Nile tilapia (Oreochromis niloticus) fry (0.2 g) was evaluated. Three isonitrogenous and isolipidic diets were formulated to contain 30% CP and 15% CL where fishmeal was substituted with Callianassa meal at 0, 25 and 50% in diets R1, R2 and R3 respectively. The experiment lasted for 6 weeks. The stocking density was 10 fish per tank in an isolated system and the capacity of each tank was 50L. Each treatment was administered in duplicates and fish were fed three times per day (09h, 13h, and 17h). The daily ration corresponds to 10% of the live weight of the fish during the first 2 weeks and was reduced to 8% and then 6% for the second and last two weeks of the trial period. At the end of the experiment, fish fed on R1 (control) diet and R2 diet (25% fishmeal replacement) had similar final weight (0.62 g), absolute mean weight gain (0.42 g), relative mean weight gain (210 %) and specific growth rate (2.50 %) and were significantly different from the values obtained from those fed on R3 diet (50% fishmeal replacement). R3 diet had the best FCR (1.42) and was significantly different from the values obtained from R1 and R2 diets but the values of the diets were not significantly different. The dry matter content of the initial fish (96.33%) and those of the R1 (94.12%) and R2 (95.71%) diets did not differ significantly but were slightly higher than that of the value obtained from fish fed on R3 diet (91.15). The protein content of the initial fish (49.63%) was significantly lower than the values obtained from fish fed on R3 diet (61.95%), R1 diet (54.74%) and R2 diet (52.59%). The fat content of the initial fish (41.51%) was higher than the values obtained when fish were fed on the experimental diets. Among the tested diets, the higher the crustacean meal in the diet, the lower the fat content of the fish muscle. The fat content of R1 (control) diet (29.56%) was slightly higher than the value of R3 diet (24.44%) and slightly lower than R2 diet (32.56%). It is concluded that crustacean meal can replace 25% of fishmeal in the diet of Nile tilapia (Oreochromis niloticus) fry at 0.2 g without any effect on the growth performances and feed efficiency.

Effect of microencapsulated fish oil powder on selected quality characteristics of chicken sausages.

Encapsulation of fish oil for use as oil powder for the human food industry offers new product design possibilities. The fat content of fish is unique in the amount of of long chain n-3 fatty acid that it contains. It can be expected that developing innovative food products with significantly improved nutritional value can simultaneously affect their rheological and sensory qualities in different ways. The present study aimed to compared the influence of the addition of fish oil and microencapsulated fish oil on the mechanical, structural, and sensory properties of poultry sausages during 21-day storage. In comparison with other systems, sausages enriched with microencapsulated fish oil were characterized by a greater capacity to accumulate potential strain energy (G') and by statistically significantly greater hardness measured in all the storage periods that were tested. The sausages enriched with microencapsulated fish oil were characterized by higher water activity than the other sausage variants. The analysis of cryo-scanning electron microscopy (cryo-SEM) images indicated the presence of a large evenly dispersed oil phase and microcapsules in the structure of the sausages. The sample with the addition of microcapsules was characterized by higher values on the smell and consistency parameters. The better results in the sensory evaluation of the structural parameters of the sample with microcapsules were consistent with the results of instrumental assessments. The use of microencapsulated fish oil powder as an ingredient of chicken sausages therefore seems to be a promising concept. © 2019 Society of Chemical Industry.

Growth performance of Heterobranchus longifilis, (Valenciennes, 1840) Fingerlings Fed with Nymphaea lotus (Linné, 1753)

A 56-day feeding trial was performed to examine the effects of using Nymphaea lotus leaf meal (NLM) on growth performance, feed utilization, body composition, and survival rate of African catfish (Heterobranchus longifilis). Five treatment groups in triplicates with an average of the initial weight of 0.26±0.07g were fed diets incorporated with graded levels of NLM (0, 10, 20, 30 and 40%). The obtained results showed that higher final body weight (FBW), daily weight gain (DWG), and specific growth rate (SGR) were observed with fish fed the control diet (CD) and NLM at the level of 20% compared to those of fish fed other diets. Protein efficiency ratios (PER) were not altered with dietary treatment. In addition, feed conversion ratio (FCR) of fish groups fed up to 30% of NLM were not varied (p&gt;0.05), meanwhile, daily feed intake of fish fed NLM diets exhibited lower values compared to those of fish fed CD. Final whole body proximate compositions of catfish showed no significant differences (P&gt;0.05) except for the body total fat and ash contents. Fat contents of fish fed diets incorporated with NLM were significantly lower than those of fish fed the control diet (CD) (P&lt;0.05). Meanwhile, ash contents of fish fed diets incorporated with high levels of NLM (30, 40%) were significantly lower than those of fish fed the control diet (CD) (P&lt;0.05). Survival rates ranged between 72 - 80% and there were no differences among all groups (P &gt; 0.05). Therefore, the results of the present study suggest that up to 20% of NLM protein can be incorporated in the diet of African catfish with no adverse effects on growth performance, feed utilization, and survival rate.

ANALISIS KADAR PROTEIN DAN LEMAK PADA IKAN JULUNG-JULUNG ASAP (Hemiramphus far) ASAL KECAMATAN KAYOA MALUKU UTARA DENGAN METODE KJELDAHL DAN GRAVIMETRI

Content Analysis of Protein And Fats In fish smoked julung-julung (Hemiramphus far) Origin of North Maluku, Subdistrict Kayoa with Kjeldahl Method and Gravimetri Method . An investigation of analysis of protein and fat content in fish smoked julung-julung ( Hemiramphus far ) Origin Of North Maluku,District kayoa with kjeldahl method and gravimetri method. This study aimed to obtain scientific data about the content of protein and fat in fish smoked julung-julung ( Hemiramphus far ) .This includes research on the protein nitrogen content of the test by Kjeldahl Method and analysis of fat content by using the method showed that the levels Gravimetri. The result showed that the samples of smoked fish fated to be unlucky-fated to unlucky ( Hemiramphus far ) obtained A water content of 13,90%, protein content of 71,03% and fat content 4,13% and in fish simple fated to be unlucky-fated to unlucky ( Hemiramphus far ) obtained B water content of 14,07%, protein content of 71,67% and fat content 5,38%. Keywords : Smoked fish julung-julung, protein, fat, kjeldahl and gravimetri.

ANALISIS KADAR PROTEIN DAN LEMAK PADA IKAN JULUNG-JULUNG ASAP (Hemiramphus far) ASAL KECAMATAN KAYOA MALUKU UTARA DENGAN METODE KJELDAHL DAN GRAVIMETRI

Content Analysis of Protein And Fats In fish smoked julung-julung (Hemiramphus far) Origin of North Maluku, Subdistrict Kayoa with Kjeldahl Method and Gravimetri Method . An investigation of analysis of protein and fat content in fish smoked julung-julung ( Hemiramphus far ) Origin Of North Maluku,District kayoa with kjeldahl method and gravimetri method. This study aimed to obtain scientific data about the content of protein and fat in fish smoked julung-julung ( Hemiramphus far ) .This includes research on the protein nitrogen content of the test by Kjeldahl Method and analysis of fat content by using the method showed that the levels Gravimetri. The result showed that the samples of smoked fish fated to be unlucky-fated to unlucky ( Hemiramphus far ) obtained A water content of 13,90%, protein content of 71,03% and fat content 4,13% and in fish simple fated to be unlucky-fated to unlucky ( Hemiramphus far ) obtained B water content of 14,07%, protein content of 71,67% and fat content 5,38%. Keywords : Smoked fish julung-julung, protein, fat, kjeldahl and gravimetri.

Fish Consumption in Infancy and Asthma-Like Symptoms at Preschool Age

JC Kiefte-de Jong, JH de Vries, OH Franco. Pediatrics. 2012;130(6):1060–1068 This study evaluated whether the timing of introduction of fish and the amount of fish consumed were associated with asthma-like symptoms at age 48 months. Patients were recruited from a population-based, multiethnic prospective birth cohort of 7210 children in Rotterdam, Netherlands, who were born between April 2002 and January 2006. Nutritional data were collected from children at age 14 months by using a semiquantitative food frequency questionnaire, which assesses timing of fish consumption, fat content of fish, and amount …

Metals and other elements in tissues of wild fish from fish farms and comparison with farmed species in sites with oxic and anoxic sediments

Farmed fish and wild fish aggregating in the vicinity of four Mediterranean fish farms with different environmental conditions were sampled. Levels of metals (including As and Se) were measured in the muscle, liver, gills, bone and intestine. The wild fish from sites with anoxic substrata accumulate metals (including As and Se) from the ambient habitat in their gills whereas those from sites with oxic substrata concentrate these elements through their diet in their intestine. Tissues of wild fish aggregating around farm cages accumulate a greater number of these elements and with higher concentrations than farmed fish. Habitat, diet, ecological needs, fat content of fish, and protein expression may play an important role in these element differences between fish species. Fe in flathead grey mullet, As in surmullet, rainbow wrasse, grey gurnard and picarel and Hg in bogue may pose a risk for human health. Farmed and wild fish are good sources of P, K, Cr and Se while flathead grey mullet, picarel and comber are excellent sources of Ca and Se.

Changes in Moisture, Protein, and Fat Content of Fish and Rice Flour Coextrudates during Single-Screw Extrusion Cooking

Changes in proximate composition of fish and rice flour coextrudates like moisture, protein, and fat content were studied with respect to extrusion process variables like barrel temperature, x 1 (100–200 °C); screw speed, x 2 (70–110 rpm); fish content of the feed, x 3 (5–45%); and feed moisture content, x 4 (20–60%). Experiments were conducted at five levels of the process variables based on rotatable experimental design. Response surface models (RSM) were developed that adequately described the changes in moisture, protein, and fat content of the extrudates based on the coefficient of determination (R 2) values of 0.95, 0.99, and 0.94. ANOVA analysis indicated that extrudate moisture content was influenced by x 4, protein content by x 1 and x 3, and fat content by x 3 and x 4 at P < 0.001. Trends based on response surface plots indicated that the x 1 of about 200 °C, x 2 of about 90 rpm, x 3 of about 25%, and x 4 of about 20% minimized the moisture in the extrudates. Protein content was maximized at x 1 of 100 °C, x 2 > 80 rpm, x 3 of about 45%, and x 4 > 50%, and fat content was minimized at x 1 of about 200 °C, x 2 of about 85–95 rpm, x 3 < 15%, and x 4 of about >50%. Optimized process variables based on a genetic algorithm (GA) for minimum moisture and fat content and maximum protein content were x 1 = 199.86, x 2 = 109.86, x 3 = 32.45, x 4 = 20.03; x 1 = 199.71, x 2 = 90.09, x 3 = 15.27, x 4 = 58.47; and x 1 = 102.97, x 2 = 107.67, x 3 = 44.56, x 4 = 59.54. The predicted values were 17.52%, 0.57%, and 46.65%. Based on the RSM and GA analysis, extrudate moisture and protein content was influenced by x 1, x 3, and x 4 and fat content by x 2, x 3, and x 4.

A Review on Fish Lipid: Composition and Changes During Cooking Methods

Fish lipids are known to be beneficial for human health since they are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). This benefit can be affected by some processing or cooking methods. The effects of different cooking methods on lipid content and fatty acid composition of different fish species have been previously studied. In this article, the fish lipid characteristics and their changes during different cooking methods were reviewed. The fat content and fatty acid composition of fish vary according to the species, season, and environmental conditions. The fish lipid characteristics also change during different cooking processes. Frying generally gives higher changes in the fish lipid composition than other cooking methods. For example, frying results in higher losses of DHA and EPA (compared to other cooking methods). Further, the lipid changes occurring during frying depend on the fat content of the fish, the frying oil composition, and the type of frying technology.

Fish intake and type 2 diabetes in Japanese men and women: the Japan Public Health Center–based Prospective Study

Although fish intake can improve glucose metabolism, results of some prospective studies in Western populations suggest potential adverse effects of environmental contaminants in fish on type 2 diabetes risk. However, data from populations with high fish consumption are scarce. We prospectively investigated the association between fish intake and type 2 diabetes risk in Japanese adults. The participants were 22,921 men and 29,759 women aged 45-75 y who completed a questionnaire of the second survey for the Japan Public Health Center-based Prospective Study and who had no history of diabetes. Diet was ascertained by using a 147-item food-frequency questionnaire. ORs of self-reported, physician-diagnosed type 2 diabetes over 5 y were estimated by using logistic regression. During the 5-y period, 971 new cases (572 men and 399 women) of type 2 diabetes were self-reported. In men, fish intake was significantly associated with a decreased risk of type 2 diabetes; multivariable-adjusted ORs of type 2 diabetes for the highest compared with the lowest quartile of intake were 0.73 (95% CI: 0.54, 1.00; P-trend = 0.04) for total fish and seafood and 0.68 (95% CI: 0.50, 0.92; P-trend = 0.016) for small and medium fish (horse mackerel and sardine, saury and mackerel, and eel). Additional analysis by fat content of fish did not detect any significant association for each category. In women, fish intake was not appreciably associated with type 2 diabetes risk. In a population with high fish and seafood intake, fish consumption was associated with a lower risk of type 2 diabetes in men but not in women.

Study on Mid-Infrared Transmittance Spectroscopy for Fast Measurement of Crude Fat Content in Fish Feeds Based on BPNN and LS-SVM

The crude fat content in fish feeds was determined using mid-infrared transmittance spectroscopy and chemometrics fast and non-destructively. A total of 225 samples were prepared for spectra collecting from a FT/IR-4000 Fourier Transform Infrared Spectrometer (400-4000cm-1). Principal component analysis (PCA) was carried out and spectral data were compressed into several new variables, which can explain the most variance of original spectra. The first six PCs were used as inputs of back-propagation neural network (BPNN) and least squares-support vector machine (LS-SVM) to create the calibration models. Compared with BPNN, a slightly better prediction precision was achieved based on LS-SVM with correlation coefficient (R) = 0.9757 and root mean square error for prediction (RMSEP) = 0.2579. The overall results indicated that mid-infrared spectroscopy incorporated to chemometrics was promising for the accurate assessment of crude fat content in fish feeds.

Fish oil: production and use now and in the future

AbstractThe global production of fish oil is around one million tonnes. This production is expected to be maintained. Rich in long‐chain omega‐3 fatty acids, especially EPA and DHA, it can supplement diets inadequate in these fatty acids such as those in many Western countries. Farmed fish, especially oily fish such as salmonids fed on fish oil provide an excellent source of these acids. Fish oil can be used directly in a purified form (nutraceuticals) in a wide range of foods. The daily recommended intake of EPA plus DHA of 0.25 to 0.50 g can then be met.

A Comparison of Selected Rapid Methods for Fat Measurement in Fresh Herring (Clupea harengus)

Several methods exist for the determination of fish-fat content. This study compares the accuracy of four of these methods against reference Soxhlet measurements, i.e., the Torry Fatmeter, a microwave method, near-infrared reflectance spectroscopy and a commercial modification of the Soxhlet procedure (the fexIKA control extraction method). Using 60 herring samples from a single 3-month period, the standard errors of prediction of these methods were 1.37, 0.79, 0.8 and 1.36%, respectively. Associated regression coefficients of 0.84, 0.95, 0.95 and 0.84, respectively were also obtained. Values predicted by Torry Fatmeter were unaffected by filleting or by previous freezing of the fish. However, icing and desiccation did affect the predictive accuracy for this instrument.

Serum phospholipid fatty acid composition and habitual intake of marine foods registered by a semi-quantitative food frequency questionnaire.

To examine the relation between consumption of fish and fish products registered by a comprehensive food frequency questionnaire and the composition of fatty acids in serum phospholipids. Cross-section study. Cardiovascular screening centre in Trondheim, Mid-Norway. Of 256 eligible women 242 agreed to participate in the present study. Altogether 234 middle-aged women (91.4%) completed the questionnaire and gave a valid blood sample. Total frequency consumption of fish for dinner showed only weak association with serum phospholipid fatty acid composition. In separate analyses of lean and fatty fish, consumption of fatty fish was negatively associated with n-6 and positively associated with n-3 fatty acids in serum phospholipids, while no significant associations were found for lean fish consumption. Cod liver oil consumption was strongly related to the phospholipid fatty acid composition. The associations improved moderately when adding portion size information. Spearman's correlation coefficient between dietary intake of eicosapentaenoic acid (EPA) and serum phospholipid EPA was 0.58, and Spearman's correlation coefficient between intake of docosahexaenoic acid (DHA) and serum phospholipid DHA was 0.53. This study suggests that in populations with a high consumption of fish and cod liver oil, habitual intake can be reflected in serum phospholipids. However, as the fat content of fish is highly variable, separate registration of lean and fatty fish consumption is needed.

Quantifying Dietary Protein Level for Maximum Growth and Diet Utilization of HybridClariasCatfish,Clarias macrocephalus×C. gariepinus

A feeding trial to quantify dietary protein level for maximum growth and diet utilization was conducted in hybrid Clarias catfish fingerlings. Five fish meal-soybean meal based diets were formulated to contain protein levels of 25-45% at 5% increments and were isocaloric with digestible energy of 280 kca1/100 g. Diets were fed to apparent satiation twice daily for 10 weeks to 2.5-g hybrid Clarias catfish held in fifteen 80-L glass aquaria. The study showed that maximum specific growth rate and lowest feed conversion ratio were attained at 40% protein level. Protein efficiency ratios and apparent net protein retention of fish fed 35 and 40% protein were higher (P < 0.05) than those fed the other diets. Fat contents of fish fed 25 and 30% protein were higher than those of fish fed higher protein levels. Ash was high only for the fish fed 25% protein, but no differences were found in those fed higher protein levels. This study indicates that juvenile hybrid Clarias catfish require a diet containing 40% prote...