Niloticus Fingerlings Research Articles

Digestibility and feeding value of some feed ingredients fed to tilapia Oreochromis niloticus (L.)

The apparent digestibility of protein, organic matter and energy of high-fibre and fibre-reduced sunflower cakes, Kenya's ‘omena’ fishmeal, anchovy fishmeal and wheat bran were investigated in tilapia Oreochromis niloticus (L.) fingerlings. The feeding values and protein qualities of the above ingredients were also determined at two dietary protein levels. Fourteen diets were formulated, and each was provided to three tanks containing 12 fish in Expt 1 (digestibility study) and 25 fish in Expt 2 (feeding trial). Water temperatures and dissolved oxygen concentrations were maintained above 26 °C and 5.5 mg L−1 respectively. Anchovy and ‘omena’ fishmeals each had an apparent digestibility coefficient for protein (ADC-P) of 90%, whereas the fibre-reduced and high-fibre sunflower cakes had ADC-P values of 89% and 86%. Wheat bran had an ADC-P value of 75%, which was significantly lower than those found for the other test ingredients. Apparent digestibility coefficients for energy (ADC-E) and digestible energy values (DE) were 86% and 78% and 4003 kcal kg−1 and 3624 kcal kg−1 for anchovy and omena fishmeals respectively. The corresponding values for the plant protein sources were 42% and 30% and 2200 kcal kg−1 and 1400 kcal kg−1 for the fibre-reduced and high-fibre sunflower cakes respectively. Diets based on the fibre-reduced cake had higher levels of all amino acids than those based on the high-fibre cake. Fish fed diets with 30% protein gained 40 g and had a feed conversion ratio (FCR) of 1.87, whereas those fed diets with 20% protein gained 35 g and had a FCR of 2.2. The source of protein had a significant effect on weight gain.

Evaluation of Sun-Dried Water Fern, Azolla africana and Duckweed, Spirodela polyrrhiza in Practical Diets for Nile Tilapia, Oreochromis niloticus Fingerlings

Two aquatic plants: water fern, Azolla africana and duckweed, Spirodela polyrrhiza were evaluated as feedstuffs in production diets for Nile tilapia, Oreochromis niloticus fingerlings. Eleven diets (30% crude protein) containing fish meal protein substituted at a rate of 5, 10, 20, 30, and 100% for either of the plant ingredients were formulated. A diet without any of the plant ingredients served as the control. Nile tilapia fed diets containing duckweed showed superior growth performance. There were no significant differences (P > 0.05) in growth responses of fish fed either 10% duckweed and 5% water fern dietary inclusion or the control diet. There was a growth depression in fish with increased dietary inclusion of both plants. The most cost-efficient diet was obtained in a diet with 30% duckweed dietary inclusion. Results of this study indicated that duckweed and water fern could be substituted for fish meal protein up to 10% and 5%, respectively, in low-cost diets for Nile tilapia without compromising growth. However, complete replacement of fish meal or soybean meal by water fern or duckweed decreases growth rates and should not be used in tilapia diets.

Acceptability and digestibility by tilapia Oreochromis niloticus of feeds containing cocoa husk

The acceptability, digestibility and nutrient utilization of feeds containing cocoa husk were determined for tilapia Oreochromis niloticus fingerlings reared in a recirculation system. Three semipurified isonitrogenous diets formulated to contain 0, 100 and 200 g kg−1 of cocoa husk were fed to satiation three times daily. Although the feeds containing cocoa husk were acceptable to the fish, as indicated by their voracious consumption and positive weight gains, there were significant (P 0.05) by the 100 g kg−1 cocoa husk feed treatment. The consumption of the cocoa husk feeds could compensate for their low digestibility under acceptable fish yields and returns.

Replacing dietary corn with barley seeds in Nile tilapia,Oreochromis niloticus(L.), feed

Four isocaloric–isonitrogenous rations containing 0%, 15%, 30% and 51% of ground barley seeds as a replacement for dietary corn were fed to three replicate groups of Oreochromis niloticus (Linnaeus) fingerlings with a mean initial weight of 3.5 g. The randomly selected fish were tested for 9 weeks in 60 L circular tanks. Each tank was considered as an experimental unit. The tanks were put together in a water recirculating system using filtered and aerated ground well water (24 ± 3 °C). Tilapia weight gain, feed conversion, specific growth rate and protein efficiency ratio were similar in fish fed diets containing 15% and 30% barley and were superior to those fed diets containing 0% control and 51% barley. There were no differences between tilapia fed diets containing 0% and 51% barley. Body moisture, crude fat, crude protein and total ash did not change as the level of barley in the feeds was increased.

Total replacement of fish meal with animal protein sources in Nile tilapia, Oreochromis niloticus (L.), feeds

The effects of total replacement of dietary fish meal (FM) with animal protein sources on the growth, feed efficiency and profit indices of Nile tilapia, Oreochromis niloticus (L.), were investigated. Shrimp meal (SM), blood meal (BM), meat and bone meal (MBM), BM + MBM mix and poultry by-product meal (PBM) replaced FM in six isonitrogenous (30% crude protein), isocaloric (400 kcal GE 100 g–1) diets. The diets were fed to O. niloticus fingerlings (12.5 g) to satiation twice a day for 150 days. The growth of fish fed SM, PBM and MBM was not significantly different from those fed the FM-based diet, while feed conversion and protein efficiency ratios were significantly retarded. Further reduction in fish performance was noticed when BM or BM + MBM replaced FM in the control diet. Cost–benefit analyses of the test diets indicated that these sources were economically superior to FM. The PBM-based diet produced higher carcass lipid than other diets. Fish fed SM, MBM and PBM diets had significantly higher ash contents (P < 0.05).

Physical and nutritional properties of moist fermented fish silage pellets as a protein supplement for tilapia ( Oreochromis niloticus)

Fish silage was prepared by fermentation of stunted tilapia with 50 ml/kg Lactobacillus plantarum starter culture and 150 g/kg sugar beet molasses at 30°C for 7 days, pasteurized, neutralized, and stored at 30°C for 180 days. Addition of 50 ml/kg onion extract proved effective as lipid antioxidant, with peroxide values lower than the control ( P<0.05). The wet silage was mixed (2:1, w:w) with poultry by-product meal, soybean-hydrolysed feather meal blend or menhaden fish meal; and each mixture pelleted by cold extrusion method. The moist pellets maintained a firm consistency during water immersion for 10 min and pellet stability was similar ( P>0.05) among diets. Protein and lipid losses were low (<15%) on a per gram diet recovered basis. All-male Oreochromis niloticus fingerlings (mean weight, 56.2±3.7 g) were fed each pellet at 4% of body weight/day for 15 days in a recirculated system (temperature, 27°C; flow, 3 l/min). Apparent digestibility coefficient (ADC) for dry matter, crude protein and gross energy of the pellets were high (>80%) and similar ( P>0.05) among diets. Moist fish silage pellets were physically stable and highly digestible to O. niloticus, and suitable as farm-made feeds for fish.

Replacing dietary starch with pitted date fruit in Nile tilapia Oreochromis niloticus (L.) feed

Four isocaloric-isonitrogenous rations containing various levels (0%, 15%. 30% and 45%) of wasted date as a replacement for starch were fed to three replicate groups of Oreochromis niloticus (Linnaeus) fingerlings with a mean initial weight of 2.5 g. Ten randomly selected fish were tested for 9 weeks in 60-1 circular tanks. Each tank was considered as an experimental unit. The tanks were put together in a flow-through system utilizing filtered and aerated ground or well water (24 ± 3°C). Tilapia weight gain, feed conversion, specific growth rate and protein efficiency ratio were improved with diets containing date (15%, 30% and 45%) as compared with the starch diet (0% date diet). The diet containing 30% date was superior to all other test diets in terms of all the above growth parameters. Body moisture, crude protein and total ash were gradually increased as the level of date in the feeds was increased, while body fat was reduced.

Replacing palm oil for soybean oil in tilapia, Oreochromis niloticus (L.), feed

Four isonitrogenous and isocaloric semi-purified feeds containing various levels of palm oil (0,1, 2 and 3%) as a replacement for soybean oil were fed to three replicate groups of tilapia, Oreochromis niloticus (L.), fingerlings, mean initial weight 5.5 g, in 45-l aquaria for 5 weeks under controlled laboratory conditions. Weight gain, feed conversion ratio, protein efficiency ratio and the chemical composition of the fish bodies did not vary significantly (P > 0.05). These results indicate that palm oil could replace soybean oil in feeds for O. niloticus fingerlings without any negative effect on the fish growth or body composition under these conditions.

Replacing fish meal with chicken offal silage in commercial Oreochromis niloticus (L.) feed

Four isocaloric isonitrogenous rations containing various levels (0,10, 15 and 20%) of chicken offal silage as a replacement for fish meal were fed to three replicate groups of Oreochromis niloticus (L.) fingerlings with a mean initial weight of 10.8g. Ten fish per tank were tested for 5 weeks in 40-1 aquaria. The aquaria were put together in a flow-through system utilizing underground water (24 ± 3°C). Weight gain, feed conversion, protein efficiency ratio and proximate body composition did not vary significantly between treatments. These results indicate that, on an isocaloric/ isonitrogenous basis, chicken offal silage can make up as much as 20% of O. niloticus commercial feed as a replacement for fish meal without any effect on growth or proximate body composition under the experimental conditions.

Water stability, nutrient leaching and nutritional properties of moist fermented fish silage diets

Fermented fish silage was prepared from whole mixed-sex tilapia ( Oreochromis niloticus), 15% molasses and 5% Lactobacillus plantarum starter culture and used as protein source in tilapia diets. Four alternative binders (carboxymethyl cellulose, corn starch, guar gum or wheat gluten) were incorporated in diets at 3% and their effects on water stability and nutrient leaching were determined. Water stability of the pellets showed that high physical stability of the pellets was maintained regardless of the binder used, and losses of total nitrogen were low (< 3%) on a per gram diet recovered basis. All-male O. niloticus fingerlings (mean weight, 48·9 g) were fed the appropriate diets at a rate of 5% of body weight per day, twice daily, for 30 days in a recirculated water system with water temperature maintained at 27°C. Apparent digestibility coefficients for dry matter, nitrogen or lipid in the diets were high and similar when carboxymethyl cellulose, corn starch or wheat gluten was used as the binder; but were reduced ( P < 0·05) with guar gum.

Riboflavin Requirement of Fingerling Red Hybrid Tilapia Grown in Seawater

AbstractRed hybrid tilapia Oreochromis mossambicus×O. niloticus fingerlings were fed diets containing 0, 2.5, 5.0, 10.0, 20.0 and 40.0 mg/kg, and 0, 2.5, 5.0, 7.5, 10.0 and 20.0 mg/kg of riboflavin in separate 8 and 12 wk feeding studies, respectively. The dietary riboflavin level required to provide maximum growth and survival, and prevent deficiency symptoms in red hybrid tilapia fingerlings was found to be approximately 5 mg/kg of diet. In both trials, fish fed the diet devoid of supplemental riboflavin exhibited anorexia, reduced growth and nervous symptoms after 4–6 wk. Mortality began to occur after the sixth week. None of these abnormalities were observed during the first 6 wk in fish fed the riboflavin supplemented diets. However, by the seventh week, fish fed the diet supplemented with 2.5 mg/kg of riboflavin showed reduced appetite and growth rate. In both experiments, short body dwarfism was observed during week 8 for fish fed the diet without riboflavin supplementation. In experiment 1, fish fed the riboflavin‐deficient diet had lens cataracts at week 8. This deficiency sign was not observed in experiment 2. Histological studies of liver, kidney, spleen, lateral muscle, gill and gastrointestinal tract revealed no major histopathological changes.

Performance of juvenile Oreochromis niloticus (L.) reared on diets containing cowpea, Vigna catiang, and black gram, Phaseolus mungo, seeds

Sixteen isocaloric diets containing one of three protein levels (20, 25 and 30%) were prepared by partially or totally replacing fish meal with seeds of the legume Vigna catiang (cowpea) and Phaseolus mungo (black gram). Oreochromis niloticus fingerlings (mean weight of 2.60±0.52 g) were fed the test diets twice daily to satiation over a 70-day period. Poor growth rates were noted when fish meal was completely replaced by each of the plant protein sources. Weight gain generally declined as the dietary level of legume seeds increased. Poor feed conversion was observed for fish fed diets with higher plant materials at 20% dietary protein. PER tended to increase with decreasing dietary protein level. Carcass lipid of fish fed 20% protein diets was increased significantly except for one group. It was noted that each of the tested legume seeds could replace about 33% of the fish meal in the test diets without any adverse effect on growth rate.

Evaluation of a practical tilapia feed using a saturation kinetic model

1. 1. Two practical Tilapia feeds were fed in ten graded levels to three replicate groups of Oreochromis niloticus fingerlings (mean weight 3 g). Ten fish per group were tested for 5 weeks in 10 gallon (371) aquaria. 2. 2. The dietary nutrient response of the two practical tilapia feeds fit the saturation kinetics model. O. niloticus weight gain and net nutrient (crude protein gross energy, crude fat) deposition were described as a function of the dietary nutrient intake graphically and numerically. 3. 3. Comparison of the abilities of the two diets and their nutrients to promote O. niloticus weight gain or net nutrient deposition were based on parameters calculated from the saturation kinetics model as follows: (1) R max (maximum response such as weight gain or net nutrient deposition) of O. niloticus fingerlings as a result of feeding a specific diet or nutrient, (2) K 0.5 (dietary nutrient intake level that produced half maximum response by the fish), and (3) Ir = 0 (the dietary or nutrient intake at maintenance level no gain no loss). 4. 4. Application of the model may provide a useful comparison of diets and their nutrients. Additionally, it may provide information concerning maximum efficiency, overall efficiency, and rates of utilization.

Accumulation of diflubenzuron in bolti fish Orechromis niloticus

Orechromis niloticus fingerlings were exposed to the insect growth inhibitor diflubenzuron 1-(2,6-Difluorobenzoyl)3-(4-chlorophenyl)urea for 21 days. Diflubenzuron was introduced to the aquariums where fish were maintained at the beginning of the experiment, then its level in water, gills and liver was detected after 1, 7, 14 and 21 days. The fish accumulated diflubenzuron 76 and 99 times greater than the water content when kept in an ambient concentration of 2.5 and 5 mg/l, respectively, indicating a low bioaccumulation potential. Some degradation products of diflubenzuron were found mainly in liver and water.

Effects of different levels of blood meal in pelleted feeds on tilapia, Oreochromis niloticus, production in floating bamboo net-cages

This paper reports the preliminary results obtained from rearing Oreochromis (= Tilapia) niloticus fingerlings (3.5 g average initial weight) at a rate of 100/m 3 in floating bamboo net-cages for 120 days to evaluate the effect of varying levels (50%, 25% and 10%) of blood meal in feeds. The pelleted feeds were fed at rates of 10%, 5% and 3% of the fish biomass during the 1st, 2nd, and 3rd plus 4th months of the experiment respectively. The feed containing 10% blood meal was the most efficient in terms of total fish production, average weight gain and average final fish weight.

Recruitment control and production of market‐size Oreochromis niloticus with the predator Lates niloticus L. in the Sudan

Experiments were conducted in earth ponds (242–1260m2) to evaluate the Nile perch (Lates niloticus L.) as a predator for recruitment control and the production of marketable Oreochromis niloticus L. in the Sudan. Supply of the predatory fish was maintained by induced spawning of L. niloticus brooders by raising the water level in a 1–0 ha earth pond. Lates niloticus fingerlings (7–5 cm total length) were then stocked with same size O. niloticus at the ratios 1:5, 1:10 and 1:15, Lates:Oreochromis, respectively. Over a period of 7 months Lates niloticus reduced young 50g) Oreochromis population and enhanced the production of preferred‐size ( 200 g) Oreochromis. The ratio 1:5 Lates:Oreochromis was established to be the most desirable for Lates‐with a total production of 0.2428 kg/m2 of O. niloticus with 55.7% (by weight) at the target size averaging 287.5g. The ratios 1:10 and 1:15 produced 0.2106 and 0.2153 kg m2 of O. niloticus, with 49.4% and 16.9% averaging 235.0 and 210.0 g, respectively.

Ascorbic acid requirements in relation to wound healing in the cultured tilapia Oreochromis niloticus (Trewavas)

. Ascorbic acid depleted Oreochromis niloticus fingerlings were fed on each of three diets providing nil, normal and luxus levels of the vitamin, after small surgical incisions had been made in the dursoluteral musculature. Fish from each group were sampled regularly over 16 days and histopathological evaluation of the lesion area carried out. The tissue ascorbate levels were measured in each group during the study. The results showed that the epithelial element of the healing process developed irrespective of the vitamin level but although fibroblast activity was marked in all three groups, coltagenization was very much slower in the deficient group, and in these the lesion was not mature, even at the termination of the experiment.

The utilization of a filamentous green alga ( Cladophora glomerata (L) Kutzin) as a protein source in pelleted feeds for Sarotherodon (Tilapia) niloticus fingerlings

Duplicate groups of S. niloticus fingerlings were fed each of five different diets for 8 weeks. The diets contained 30% crude protein supplied by varying proportions of fishmeal and C. glomerata meal. The five diets were formulated to supply fishmeal protein: C. glomerata meal protein ratios of 30 : 0 (diet 1), 25 : 5 (diet 2), 20 : 10 (diet 3), 15 : 5 (diet 4) and 10 : 20 (diet 5) respectively. A sixth diet (diet 6) containing 25% crude protein supplied entirely by C. glomerata meal was also fed. Diets 1 and 2 produced significantly the highest growth rates and best protein utilization. Highest values for protein digestibility were found in diets 2 and 3 (94.5 and 93.9% respectively) although the values were not significantly different from other treatments. Weight gain and protein utilization decreased as the level of algal protein increased in diets 2 to 6. Carcass analysis revealed a decrease in lipid and protein contents with increasing levels of algae in the diet. It is postulated that algal meals are viable partial dietary protein sources for tilapia.