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Nutritional aspects of nile tilapia (Oreochromis niloticus) silage
Arruda, Lia Ferraz de;Borghesi, Ricardo;Brum, Aelson;D'Arce, Marisa Regitano;Oetterer, Marília;
Ciência e Tecnologia de Alimentos , 2006, DOI: 10.1590/S0101-20612006000400006
Abstract: one third of the world's fishing produce is not directly used for human consumption. instead, it is used for making animal food or is wasted as residue. it would be ideal to use the raw material thoroughly and to recover by-products, preventing the generation of residues. with the objectives of increasing the income and the production of the industry, as well as minimizing environmental and health problems from fish residue, chemical silage from tilapia (oreochromis niloticus) processing residues was developed after homogenization and acidification of the biomass with 3% formic acid: propionic, 1:1, addition of antioxidant bht and maintenance of ph at approximately 4.0. analyses to determine the moisture, protein, lipids and ash were carried out. the amino acids were examined in an auto analyzer after acid hydrolysis, except for the tryptophan which was determined through colorimetry. the tilapia silage presented contents that were similar to or higher than the fao standards for all essential amino acids, except for the tryptophan. the highest values found were for glutamic acid, lysine and leucine. the results indicate a potential use of the silage prepared from the nile tilapia processing residue as a protein source in the manufacturing of fish food.
Toxicity of Malathion to Nile Tilapia Oreochromis Niloticus (Linn.) Fingerlings  [cached]
Virginia Cari?o,,Emmanuel Capinpin
Science Diliman , 1993,
Abstract: The toxicity of a commercial grade malathion on Nile tilapia, Oreochromis niloticus, fingerlings was determined. The 24, 48, 72, and 96-h LC50 of malathion on Nile tilapia fingerlings were 7.19, 5.43, 5.34, and 5.30 mg/l, respectively. Behavioral changes in fish included rapid opercular movement, hyperexcitability, darkening of the body, and contraction of trunk muscles. Moribund fish displayed labored opercular movement, severe contraction of the trunk muscles, erratic swimming, and total loss of equilibrium. A safe level of less than 0.53 mg/l malathion for Nile tilapia fingerlings was considered.
Toxicity and Efficacy of Lidocaine as an Anesthetic for Nile Tilapia; Oreochromis niloticus
H.H.H. Abbas,A.S. Abdel-Gawad,A.A. Akkr
Pakistan Journal of Biological Sciences , 2006,
Abstract: The anesthetic lidocaine was tested for its toxicity, efficacy and safety on Nile tilapia (Oreochromis niloticus). Toxicity values were variable and depended mainly on concentration and time of exposure. Concentrations of 60, 80 and 100 mg L-1 lidocaine were all effective for rapid anesthesia with 100% survival. In moderately rapid anesthesia, 40 mg L-1 lidocaine induced loss of equilibrium in Nile tilapia within 20 min exposure and 100% survival. Safety Index (SI) values for lidocaine on Nile tilapia indicated that the shorter the exposure time, the higher SI values. Repeated anesthesia in freshly prepared solution of lidocaine did not appear to affect on Nile tilapia sensitivity in terms of anesthetization, recovery and survival. However, results were in contrast and variable when previously prepared (old) solutions of lidocaine were used.
Skeletal Ossification Impairment in Nile Tilapia (Oreochromis niloticus) after Exposure to Lead Acetate  [PDF]
Mohey A. Hassanain,Wafaa T. Abbas,Taghreed B. Ibrahim
Pakistan Journal of Biological Sciences , 2012,
Abstract: Heavy metal pollution represents a serious problem facing many of the aquatic organisms. Lead is one of the most toxic elements found in many industrial effluents which are metabolized inside bodies and can cause skeletal deformities by impairing developmental processes and bone formation. This study was undertaken to determine the LC50 of Pb-acetate and detect the effect of 1/10 LC50 exposure on fingerlings of Nile Tilapia (Oreochromis niloticus). Modern and accurate diagnostic methods were used; Scanning Electron Microscopy (SEM) of gills, plain X-ray and Energy-dispersive X-ray Spectroscopy (EDX) of the spinal column to explain the elemental analysis. The results indicated that the 96 h LC50 of lead acetate was 146.8 mg L-1. SEM showed a distinct degeneration in gill filaments and pavement cells with increasing of mucus secretion after lead exposure. X-ray revealed slight dorsal spinal curvature. EDX analysis of the spinal column of treated fish showed decrease in calcium and phosphorus weight percents, on the other hand Pb appeared in treated fish but not in control ones. Finally this study can spot a light on the dangerous effects of lead toxicity in developing of fish and impairment of their skeletal ossification which may lead to skeletal deformities.
Protozoan and metazoan parasites of Nile tilapia Oreochromis niloticus cultured in Brazil
Wanderson Pantoja MF,Ligia Neves R.,Márcia Dias RD.,Renata Marinho GB
Revista MVZ Córdoba , 2012,
Abstract: Objective. This study describes the parasitic fauna and relative condition factor (Kn) in Nile tilapia Oreochromis niloticus L. (Cichlidae) from fish farms in the State of Amapá. Material and methods. 123 fish from four fish farms in the state of Amapá, Brazil were necropsied for parasitological and Kn analysis. Results. 64.2% of the examined fish, had the gills infected with Cichlidogyrus tilapiae Paperna, 1960 (Monogenoidea: Dactylogyridae); Ichthyophthirius multifiliis Fouquet, 1876 (Protozoa: Ciliophora), Trichodina Ehrenberg, 1830 and Paratrichodina africana Kazubski & El-Tantawy, 1986 (Protozoa: Trichodinidae). The highest prevalence found corresponded to Monogenoidea C. tilapiae while the lowest corresponded to Trichodinidae. However, I. multifiliis was the parasite that presented the greatest intensity and abundance. The differences found in the infection rates of the different fish farms due to causes further discussed. The parasitism did not influence the relative condition factor (Kn) of fish. This was the first record of P. africana in Brazil and occurred in the Eastern Amazon. Conclusions. In Brazil, Lamproglena sp. is an emerging parasite in the Southern and Southeastern regions, but this crustacean was not found in the Nile tilapia in the State of Amapá. The parasitic infections in Nile tilapia farmed in Brazil are caused by protozoan, monogenoidea, crustacea and digenea species, and the regional differences on their prevalence and intensity rates are discussed in this study.
An immunohistochemical study of gill epithelium cells in the Nile tilapia, Oreochromis niloticus.  [cached]
Sandra Mariza Monteiro,António Fontainhas-Fernandes,M??rio Sousa
Folia Histochemica et Cytobiologica , 2010, DOI: 10.5603/4239
Abstract: This study reports the first complete mapping of the gill epithelium in a tilapia species. Different gill epithelial cell types of the Nile tilapia, Oreochromis niloticus L. have been identified and located using different antisera against mammalian proteins and various histochemical techniques: Periodic Acid Schiff (PAS), Alcian Blue pH 1.0, 2.5, 3.5, Giemsa and Grimelius. The results show that the stratified filament epithelium of O. niloticus gill can be divided into two distinct regions, a superficial layer, where pavement, mucous and mitochondria rich cells can be found, and a deep layer, constituted by undifferentiated, myoepithelial-like, granular and neuroendocrine cells. V-ATPase and Na+/K+-ATPase presence allowed the identification of pavement and mitochondria-rich cells, respectively, suggesting that, in O. niloticus, pavement cells are implicated in Na+ uptake, whereas mitochondria-rich cells have a role in Cl- uptake. The use of PAS and Alcian Blue allowed the recognition of different sub-populations of mucous cells that differentiate from a common deeper precursor. Neuroendocrine markers were detected in different cell populations, stating evidence for a neuroendocrine role of mitochondria- rich cells, and suggesting the existence of distinct neural pathways, a putative O2-chemosensory and an ion regulatory pathway. A defence role was attributed to the deep filament epithelium, suggested by the presence of resident giemsa positive- eosinophil granular cells. The antibody raised against proliferating cell nuclear antigen identified two different cell types, the undifferentiated cells and myoepithelial-like cells. In the superficial layer, it is here stated for the first time the existence of vimentin positive support cells.
Growth of Nile tilapia Oreochromis niloticus fed with different levels of alcohol yeast
MEDRI, V.;PEREIRA, G. V.;LEONHARDT, J. H.;
Revista Brasileira de Biologia , 2000, DOI: 10.1590/S0034-71082000000100014
Abstract: two hundred and forty 45-day-old fingerlings of nile tilapia (oreochromis niloticus), sexually reverted with an initial average weight of 1.25 ± 0.14 g, distributed in a totally casualized delineation, during 330 days. the effect of the substitution of 10%, 20% and 30% of the ration by distillery yeast (saccharomiyces cerevisae) in balanced experimental rations on the development in the breeding of tilapias did not show a harmful effect up to the maximum tested level of 30%, showing that the choice of the yeast in the ration for these fishes depends on the availability and occasional cost. the yeast provides fish with good resistance to unfavorable environmental conditions, which could be verified since there were no statistical differences among the treatments with different levels of yeast and the witness. the long growth rate in terms of length and weight can be attributed to the little available space for each specimen, not obeying the limit of populational density, as well as reduction of food ingestion, which coincide with the winter season, above of the absence of natural feeding.
Growth of Nile tilapia Oreochromis niloticus fed with different levels of alcohol yeast  [cached]
MEDRI V.,PEREIRA G. V.,LEONHARDT J. H.
Revista Brasileira de Biologia , 2000,
Abstract: Two hundred and forty 45-day-old fingerlings of Nile tilapia (Oreochromis niloticus), sexually reverted with an initial average weight of 1.25 ± 0.14 g, distributed in a totally casualized delineation, during 330 days. The effect of the substitution of 10%, 20% and 30% of the ration by distillery yeast (Saccharomiyces cerevisae) in balanced experimental rations on the development in the breeding of tilapias did not show a harmful effect up to the maximum tested level of 30%, showing that the choice of the yeast in the ration for these fishes depends on the availability and occasional cost. The yeast provides fish with good resistance to unfavorable environmental conditions, which could be verified since there were no statistical differences among the treatments with different levels of yeast and the witness. The long growth rate in terms of length and weight can be attributed to the little available space for each specimen, not obeying the limit of populational density, as well as reduction of food ingestion, which coincide with the winter season, above of the absence of natural feeding.
Visual communication stimulates reproduction in Nile tilapia, Oreochromis niloticus (L.)
Castro, A.L.S.;Gon?alves-de-Freitas, E.;Volpato, G.L.;Oliveira, C.;
Brazilian Journal of Medical and Biological Research , 2009, DOI: 10.1590/S0100-879X2009000400009
Abstract: reproductive fish behavior is affected by male-female interactions that stimulate physiological responses such as hormonal release and gonad development. during male-female interactions, visual and chemical communication can modulate fish reproduction. the aim of the present study was to test the effect of visual and chemical male-female interaction on the gonad development and reproductive behavior of the cichlid fish nile tilapia, oreochromis niloticus (l.). fifty-six pairs were studied after being maintained for 5 days under one of the four conditions (n = 14 for each condition): 1) visual contact (v); 2) chemical contact (ch); 3) chemical and visual contact (ch+v); 4) no sensory contact (iso) - males and females isolated. we compared the reproductive behavior (nesting, courtship and spawning) and gonadosomatic index (gsi) of pairs of fish under all four conditions. visual communication enhanced the frequency of courtship in males (mean ± sem; v: 24.79 ± 3.30, ch+v: 20.74 ± 3.09, ch: 0.1 ± 0.07, iso: 4.68 ± 1.26 events/30 min; p < 0.05, two-way anova with lsd post hoc test), induced spawning in females (3 spawning in v and also 3 in ch+v condition), and increased gsi in males (mean ± sem; v: 1.39 ± 0.08, ch+v: 1.21 ± 0.08, ch: 1.04 ± 0.07, iso: 0.82 ± 0.07%; p < 0.05, two-way anova with lsd post hoc test). chemical communication did not affect the reproductive behavior of pairs nor did it enhance the effects of visual contact. therefore, male-female visual communication is an effective cue, which stimulates reproduction among pairs of nile tilapia.
Influence of Tricaine Methanesulfonate on Streptococcus agalactiae Vaccination of Nile tilapia (Oreochromis niloticus)
D.J. Pasnik,J.J. Evans,P.H. Klesius
Veterinary Research , 2012,
Abstract: Experiments were conducted to study the influence of tricaine Methanesulfonate (MS-222) on blood glucose levels and percent cumulative survival of Nile tilapia (Oreochromis niloticus) challenged with Streptococcus agalactiae 30 days post-vaccination with S. agalactiae vaccine or sham-vaccination with Tryptic Soy Broth (TSB). Anesthesia-treated fish were placed in an MS-222 (50 mg L 1) solution to achieve stage 3 of anesthesia, while control fish were placed in a sham anesthetic solution containing water but no MS-222 for an equal amount of time. All fish were then injected intraperitoneally with S. agalactiae vaccine or TSB and later injected intraperitoneally with 750 cfu S. agalactiae/fish. Blood glucose levels among the groups immediately after anesthesia (92.8 5.6 and 73.2 4.2 mg dL 1) or sham anesthesia (56.7 2.6 and 58.9 3.5 mg dL 1) were significantly higher in the MS-222-treated groups (p<0.0001). No other significant differences in blood glucose levels between treatment groups were observed at subsequent sampling points. Percent cumulative survival among challenged vaccinated fish was 50% when treated with MS-222 versus 100% when not treated with MS-222 (p<0.0001). However, percent cumulative survival among challenged non-vaccinated fish was 80% when treated with MS-222 versus 29% when not treated with MS-222 (p<0.0007). Increased blood glucose levels prior to vaccination were significantly correlated to decreased percent cumulative survival after challenge (r2 = 0.5364; p = 0.0022). Given increased blood glucose and decreased survival among MS-222-treated, vaccinated fish, consideration should be given when anesthetizing Nile tilapia with MS-222 prior to vaccination.
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