Showing papers on "Nile tilapia published in 1992"
TL;DR: It is demonstrated that O. niloticus fry require 45% protein and 400 kcal/100 g for maximum growth when reared under laboratory conditions, compared to those fed moderate- and high-energy diets.
167 citations
TL;DR: The results demonstrate net Ca2+ uptake by vertebrate skin and strongly implicate mitochondrion-rich cells as the site of Ca2+.
Abstract: The skin, particularly the opercular membrane of some teleosts, contains mitochondrion-rich "chloride" cells and has been widely used as a model to study branchial salt-extrusion mechanisms in seawater fish. Skin isolated from the operculum of the freshwater Nile tilapia (Oreochromis niloticus) can transport Ca2+ against an ionic and electrical gradient. Adaptation of Nile tilapia to a low-Ca2+ environment increased the capacity of the opercular membrane to transport Ca2+. The density of mitochondrion-rich cells increased in parallel with Ca2+ transport capacity. The results demonstrate net Ca2+ uptake by vertebrate skin and strongly implicate mitochondrion-rich cells as the site of Ca2+ uptake in fresh water.
138 citations
TL;DR: The optimal daily feeding rates of Lemna were 5, 4 and 3% of the total fish body weight on a duckweed-dry-weight basis for fish of 25 to 44 g, 45 to 74 g and 75 to 105 g in weight, respectively.
79 citations
TL;DR: Results of this study indicate that young Nile tilapia utilizes Azolla more efficiently than the adults, and fish performance continued to deteriorate with increasing dietary Azolla level in the diets.
Abstract: . Dry and fresh Azolla pinnata were evaluated as feed ingredients for fingerling and adult Nile tilapia, Oreochromis niloticus (L.). Dry Azolla was incorporated into practical diets containing approximately 30% crude protein and 360–400kcal/lOOg of GE lo replace 25,50,75 and 100% of the fish meal (FM) protein in the control diet. Fresh Azolla was also tested as a total diet for these fish. Formulated diets were fed to duplicate groups of fingerling (2–54g ± 0093) and adult (4033g ± 103) fish at a daily rate of 5% and 3% of their body weight respectively for 10 weeks. Growth and feed utilization efficiency of fish fed the control diet were significantly higher than of those fed Azolla-supplemented diets. Fish performance continued to deteriorate with increasing dietary Azolla level in the diets. This reduction was extremely sharp when dry and fresh Azolla were used as total diets. Furthermore, adult tilapia fed fresh Azolla started losing weight from the 7th week. Fish fed fresh Azolla had significantly higher moisture content than those fed formulated diets. Body protein and lipid contents were negatively correlated with Azolla levels in the diets, while body ash content showed a positive correlation. Results of this study indicate that young Nile tilapia utilizes Azolla more efficiently than the adults.
69 citations
TL;DR: Different performance rankings at each feeding phase represent strong genotype X environment interaction among these commercially important lines and grew best during the commercial feed phases, the Israel and nifi strains during the different feeding phases using the reference strain as a covariate.
40 citations
Journal Article•
TL;DR: In this article, the authors report on the socioeconomic study made on tilapia culture in seasonal ponds/ditches in Bangladesh and show that simple technology, requiring very low labor input, is economically viable and brings other benefits.
Abstract: The book reports on the socioeconomic study made on tilapia culture in seasonal ponds/ditches in Bangladesh. Results show that the simple technology, requiring very low labor input, is economically viable and brings other benefits.
38 citations
TL;DR: A bioenergetic growth model was developed to examine the integrated effects of fertilization, stocking density, and spawning on the growth of tiiapia, Oreochromis niloticus (L.), in pond aquaculture, showing that growth rates increase with higher levels of organic ferlilization and decreases with increased levels of stocking density.
Abstract: A bioenergetic growth model was developed to examine the integrated effects of fertilization, stocking density, and spawning on the growth of tiiapia, Oreochromis niloticus (L.), in pond aquaculture. The analyses showed that growth rates increase with higher levels of organic ferlilization up to 5(HJkg/ha/week. Growth rates increased with added food rations in ponds, reaching a maximum growth of 2-07g/day at about 44-48 days after stocking. Fish growth rates decreased with increased levels of stocking density. The stocking density for optimal growth is 1 fish/m"; the optimal density for total harvesting weight and fish size is 2 fish/m". Model sensitivity analysis indicated that tiiapia growth is most sensitive to catabolism (metabolism) and anabolism (synthesis) coefficients, both of which are geometrically related to the fish body weight. Food assimilation efficiency (b) and the food consumption coefficient (h) have a modest effect on fish growth. Spawning in grow-out ponds can have a major effect on fish growth.
34 citations
TL;DR: Optimum harvest time was similar for either maximizing fish yield or maximizing profit of fish harvested because the daily change in fish production cost was low for the low-input Nile tilapia, Oreochromis niloticus (L.), production system in Thailand.
Abstract: A simple method is presented for determining the optimum time to harvest fish and the effect of fertilization type on optimum harvest time for Aquaculture. Optimum harvest time was similar for either maximizing fish yield or maximizing profit of fish harvested (price of fish times fish yield minus fish production cost), because the daily change in fish production cost was low for the low-input Nile tilapia, Oreochromis niloticus (L.), production system in Thailand. At a harvest time of 150 days for an organic fertilization treatment compared to an inorganic fertilization treatment fish yield increased from l-505 t/ha to 2-295 t/ha, and profit of fish harvested increased from 15657·1 baht/ha (US$ 590-8/ha) to 25127·5 baht/ha (US$ 948-2/ha). For the organic treatment, optimum harvest time occurred at 191 days, with a fish yield of 2·328 t/ha and a profit of 25520·5baht/ha (US$ 963·0/ha), compared to the inorganic treatment where optimum harvest time occurred at 105 days with a fish yield of 1·536 t/ha and a profit of 16035·4baht/ha (US$ 605·1/ha).
25 citations
TL;DR: No positive anabolic effect was evident in response to adding FM or MT to the feed at the end of the 28-day treatment period or after an additional 6 weeks of growth without hormone.
Abstract: The androgenic and anabolic potential of fluoxymesterone (FM) was evaluated by incorporating the hormone into the feed of Nile tilapia, Oreochromis niloticus(L.) fry. Phenotypic all-male populations were produced when FM was given at 1, 5 and 25mg/kg of feed. Fry fed methyltestosterone (MT) at 60 mg/kg of feed and 0-2 mg of FM per kg of feed had a sex ratio of 97-7% and 87-3% phenotypic males.
No positive anabolic effect was evident in response to adding FM or MT to the feed at the end of the 28-day treatment period or after an additional 6 weeks of growth without hormone. Growth was less for fry which received 25 mg/kg of FM compared to those receiving lesser rates of FM, 60 mg/kg MT, and controls.
22 citations
01 Jan 1992
TL;DR: The outcomes of introductions in the Great Lakes region of Africa are reviewed in relation to the need to conserve the native fish fauna and to produce protein food for people living in the region.
Abstract: Fish introductions have been used to enhance fish production by filling a less utilized ecological niche, for aquaculture, sport and recreation, ornamental purposes and to control disease vectors and weeds. Introductions of the Nile perch Lates niliticus and the Nile tilapia Oreochromis niloticus into Lakes Victoria and Kyoga, and the clupeid Limnothrissa miodon into Lakes Kariba and Kivu have led to increases in fish catches. Unfortunately, predation by the Nile perch and competition between native cichlids and introduced tilapiine species have caused a severe decline and in some cases total disappearance of many native fish species from Lakes Victoria and Kyoga. This has generated conflicting opinions on fish introductions. This paper reviews the outcomes of introductions in the Great Lakes region of Africa in relation to the need to conserve the native fish fauna and to produce protein food for people living in the region. It also suggests guidelines to be followed before fish are introduced, e...
21 citations
TL;DR: It is supposed that exogenously administered Nα -acetylhistidine is transported to kidney via blood plasma, and effectively deacetylated to histidine by the enzyme(s) of the kidney.
Abstract: 1. 1. Nα- Acetyl - l - histidine was identified in protein-free extracts of muscle of Nile tilapia (Oreochromis niloticus), and this substance was the major component (2.8 μmol/g tissue) of the imidazole pool in the muscle of the fish. 2. 2. High Nα-acetylhistidine-deacetylating activity was found in crude enzyme solutions prepared from kidney, brain, liver and eye of the fish, and kidney was the richest source of this activity. 3. 3. After intraperitoneal administration of Nα-acetylhistidine to the fish, a drastic increase in kidney histidine concentration was observed after 2 hr. 4. 4. It is supposed that exogenously administered Nα-acetylhistidine is transported to kidney via blood plasma, and effectively deacetylated to histidine by the enzyme(s) of the kidney.
TL;DR: Ratios of 1 : 10 to 1 : 15 between Nile perch and ready-to-spawn females of O. niloticus were found to be adequate to control tilapia reproduction.
Abstract: Vulnerability of three fish groups (tilapia, common carp, mullet) to predation by Nile perch Lates niloticus was evaluated. The study was conducted in aquaria and in cages placed in concrete ponds. Common carp Cyprinus curpio was the more vulnerable to predation by Nile perch followed in order by mullet (Mugil cephulus and M. cupito) and Nile tilapia Oreochromis niloricus. Medium-size Nile perch (30–32 cm t.l.) were able to consume tilapia up to 14 cm t.l., while tilapia of 15 cm total length were not eaten. Ratios of 1 : 10 to 1 : 15 between Nile perch and ready-to-spawn females of O. niloticus were found to be adequate to control tilapia reproduction.
TL;DR: Chemical sensitivity of the Nile tilapia Tilapia nilotica to geosmin was examined by the cardiac method, and it was found that other chemoreceptors (taste buds and free neuromasts) are also important.