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Research Article
Jun 10, 2019
Effects of Dietary Yeast Extract Levels on Growth Performance, Digestibility and Antioxidant Capaci ... ty of the Taiwan Loach
An 8-week feeding trial was conducted to determine the effects of different levels of dietary Yeast Extract (YE) on growth performance, digestibility and antioxidant capacity of the Taiwan loach. The trial contained 6 diets with different levels of wet YE, namely 0%, 1%, 2%, 3%, 4% and 5% (groups T1-T6). Each group contained 8 replicates with 12 loaches. Results indicated that the Specific Growth Rate (SGR) of loaches that were fed T5 diet were significantly higher than those of the other groups, whereas the feeding rate and feed conversion rate were just the opposite. The association of the regression analysis between different dietary YE and the loach SGR were: SGR=−9244YE3+622.03YE2-3.7768YE+3.9325(p<0.05). The apparent digestibility coefficient of the dry matter and the Amylase activity levels of the loaches fed with the YE were higher than those that were fed the T1 diet. The liver SOD activity was increased significantly following the increase in the YE supplementation (p<0.05). In conclusion, YE supplementation in the loach diet could promote growth, improve feed digestion and utilization, and enhance antioxidant capacity. The optimum levels of wet YE required for feeding the Taiwan loach species were estimated to 4.16%
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Research Article
Jun 07, 2019
Optimum Harvest Time of the Nile Tilapia (Oreochromis niloticus) in Honduras: A Two Step OLS Proced ... ure to Obtain the Growth Function
Several aquaculture firms in Honduras lack a profit function for tilapia production, which complicates their decision-making. Furthermore, several statistical procedures used to obtain a production function are too complex for these firms to implement on their own. Thus, a simple, yet efficient, model was developed for these firms to follow. The model for this function consists of a gross-margin function composed of an income and a cost function. The OLS procedure in this model differs from several studies by using the OLS obtained length-weight parameter, “b” as an input to estimate “k” in a second OLS regression. The latter regression is applied to a log-lin model of a weight-based von Bertalanffy growth function. The estimated length-weight exponent, “b” used in the growth function, the growth parameter per day, “k” and the mortality parameter per day, “z” are 2.92289, 0.00821 and 0.00086 respectively. The optimum harvest time estimated for one period is 199 Days after Stocking (DAS) when there is no restriction in the market for the size of fish and 208 DAS when minimum market length is 20 cm. The optimum harvest time for infinite time horizon is 117 DAS if there is no size restriction
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Research Article
May 27, 2019
Studies on the Physicochemical Properties of Ebonyi River in Ebonyi State, Nigeria and on the Abund ... ance of Benthic Fauna during the Rainy Season
The study of physicochemical parameters have been documented, however little may still be known on how those parameters determine the abundance and composition of benthic fauna. We investigated, from May to August, 2018 the relationship between physicochemical parameters and the abundance of some benthic fauna found in Ebonyi River. Using a scoop-net, we collected samples ranging from vertebrates and invertebrates. Four sampling stations were chosen so as to encompass as a wide range of physical conditions. The mean values of dissolved oxygen (10.56 ± 0.6 mg/L), alkalinity (25.5 ± 0.3 mg/L) and hardness (15.3 ± 0.4 mg/L) were determined. We found out that the abundance of benthos was influenced by physicochemical quality of the water, habitat, and immediate substrate of occupation, tropic condition, resource partitioning and predation. Six classes of both vertebrates and invertebrates were recorded of which the class Insecta was dominant. The genera of Coenagrion nymph, Sympetrum, and Chironomus negatively correlated to the depth and velocity of water. However, we found a positive relationship between the water temperature and Belostoma genus. The negative relationships may be as a result of pollutants acquired through anthropogenic activities. However, the positive relationship between temperature and Belostoma genus may be as a result of essential resources e.g. food and mating season.
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Research Article
May 21, 2019
Chemical and Microbial Quality Assessments of Some Economic Important Artisanal Fresh Water Fish Sp ... ecies (Tilapia zilli, Clarias gariepinus, Chrysichthys nigrodigitatus and S. melanotheron) in Selected Coastal Markets of Lagos State, Nigeria
Nutritional qualities of some selected fresh water fish species sold for consumption in the Badagry, Epe, Ikorodu and Ojo areas of Lagos state, Nigeria was assessed to ascertain the wholesomeness and health risk associated with consuming the most common sort after fish in these locations. A total of 100 fish samples, Red belly Tilapia (T. zilli), African Mud Catfish (C. gariepinus), Silver Catfish (C. nigrodigitatus) and Black Chin Tilapia (S. melanotheron) (25 specimens each) with a weight ranges between 50-180 g, were collected from different locations. The samples were iced and taken to the Biochemistry and Pharmaceutical laboratory sections of the College of Medicine University of Lagos, Idi-Araba, Lagos, Nigeria. The iced samples were maintained in alternate layers of ice until spoilage was noticed. Chemical analysis was conducted using Spectrophotometer, Atomic Absorption Spectrophotometer, Sohxlet Extraction Apparatus, Thiobarbituric Acid (TBA), The Acid Value (AV), Peroxide Value (PV), Iodine value, Free Fatty Acids (FFA) and Saponification value were determined. The result indicates higher TBA (8.79 ± 0.05), (7.59 ± 0.06), (7.46 ± 0.04) and (6.99 ± 0.05) for T. zilli, C. nigrodigitatus, S. melanotheron and C. gariepinus respectively in Ojo Lagoon, higher iodine value (9.69 ± 0.01) for T. zilli in Ojo Lagoon; (8.75 ± 0.21), (9.35 ± 0.07) and (8.45 ± 0.07) for C. nigrodigitatus, S. melanotheron and C. gariepinus respectively in Epe Lagoon and the acid values (3.31 ± 0.04), (2.45 ± 0.04) and (3.79 ± 0.04) for T. zilli, C. nigrodigitatus and S. melanotheron respectively in Badagry Lagoon and (2.25 ± 0.04) in Ojo Lagoon were within the standard limits. Higher mean mould load recorded were (1.22×104), (1.78×103), (1.90×103) for C. gariepinus, S. melanotheron and T. zilli respectively in Ikorodu Lagoon, while (3.47×103) was recorded for C. nigrodigitatus in Badagry Lagoon. The results indicated a notable quality improvement leading to a high quality fish in terms of the taste, colour, odour, shelf life and market value. The high iodine value recorded in this study from different locations suggests that the fish species contain high level of unsaturated oil and as such could reduce the risk of heart diseases, high cholesterol, depression, anxiety, low immunity, cancer, eye disorders and ulcers in humans when consumed. None of the fish samples exceeded the mould load limit for fish thereby exhibiting no risk on public health; therefore the fish are wholesome and safe for human consumption.
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Research Article
Apr 26, 2019
Growth Performance of the African Catfish, Clarias gariepinus (Burchell), Fed Varying Inclusion Lev ... els of Castor Seed (Ricinus communis L.)
An 84 day feeding trial was conducted to evaluate raw and boiled castor seed (Ricinus communis L.) in the diet of Clarias gariepinus (Burchell, 1822) fingerlings with average body weight of 9.55 g ± 0.24 g. The fish were assigned to five treatments. The fish in five treatments, each replicated thrice, were fed with 37% crude protein experimental diets containing raw castor seed meal, (D1) and boiled seed diets subjected to boiling at 100ºC for 20 (D2), 35 (D3), 50 (D4) and 65 (D5) minutes respectively. Diet1 (D1) served as control and was fed to the fish in the first treatment. Castor seeds served as an isonitrogenous source of protein in the experimental diets. There were no significant differences (p>0.05) in the Mean Weight Gain (MWG), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR) and Protein Efficiency Ratio (PER) of the experimental fish fed diets D2, D3, D4 and D5. Highest percentage weight gain, SGR, FCR, PER, Net Protein Utilization (NPU) and digestibility rate were recorded in diet D4 containing castor seed boiled for 50 minutes at 100ºC. Hence, boiling of castor seeds for 50 minutes at 100ºC is considered the best approach for processing castor seeds through boiling
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Research Article
Apr 22, 2019
Dietary Tridax procumbens Meal Improved Growth and Hematology Profiles of African Catfish, Clarias ... gariepinus juveniles
The effects of Tridax procumbens supplemented into the experimental diets at different inclusion levels of Clarias gariepinus juvenile fish with mean weight 42.87 0.92 g for 56 days were investigated for growth performance and hematology profile. Ten fishes each were distributed to five treatments that contained 0, 0.05, 0.10, 0.15, and 0.20% of T. procumbens leaf meal, separately. Each treatment was replicated three times, and the fishes were fed with diets according to treatments. Physicochemical properties were monitored weekly; feeding was carried out in the morning (8:00-8:30 am) and evening (4:00-4:30 pm) daily. Routine monitoring and mortality occurrences were recorded. The growth of fish was assessed fortnightly on randomly selected fish samples, and morphometric measurements on length and weight gain of fish were assessed. Hematology examination of fish was assessed fortnightly. The results revealed that water parameters ranged within recommended limits. Fish fed inclusion level of 0.10% of T. procumbens leaf meal-based diet had the best growth weight (37.20 0.82 g). Hematology analysis shows fish fed with a diet containing 0.05% of T. procumbens to be the best: packed cell volume (PCV) (31.00 3.00%) and red blood cell (RBC) (3.43 0.33 106 ). However, a decrease in the hematology indices from fishes fed with 0.15% of T. procumbens was as follows: PCV (21 3.00%) and RBC (2.38 0.33 106 ). Highest white blood cell (WBC) was recorded in fish fed 0.15% (8100 900) and least in fish fed 0.20% (5300 500). Moreover, there is no significant difference (p 0.05) in PCV, hemoglobin (Hb), WBC, RBC, mean cell hemoglobin concentration (MCHC), mean cell hemoglobin (MCH), mean corpuscular volume (MCV), neutrophil (NEU), and lymphocyte (LYM) of the fish samples in the varying treatments; however, there was significant difference (p 0.05) in the monocyte (MON) and eosinophils (EOS). The fish were found to have developed antibodies to fight disease conditions, which enable robust growth performance and good health status
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Research Article
Mar 21, 2019
Edwardsiella Species Infection in Fish Population and Its Status in Ethiopia
The genus Edwardsiella (E.) is a Gram-negative, glucose fermentative, catalase positive, and capable of producing H2S and indole (except E. ictaluri). It comprises the three previously isolated E. tarda, E. hoshinae, E. ictaluri and the two recently isolated E. piscicida, E. anguillarum species. Except E. hoshinae, other Edwardsiella spp. are pathogenic to fish, and only E. tarda is known to cause human infection. Pathogenic Edwardsiella spp. uses the virulence factors that include flagellin, adhesin, hemolysin, type III and type VI secretion systems to gain entry into and survive within the host. The status and distribution of edwardsiellosis in fish and its public health significance in Ethiopia is poorly understood, and thus needs further studies as aquaculture is growing in the country. Since differentiation of Edwardsiella spp. based only their phenotypic characteristics is less discriminatory than their genotypic characteristics, thus phenotypic studies should always be followed by genetic analysis of the bacterium. Therefore, the objective of this seminar paper is to review Edwardsiella infections in fish, its zoonotic importance and status in Ethiopia.
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Research Article
Mar 04, 2019
Liver Enzyme Activity of Tilapia zillii and Mugil capito Collected Seasonally from Qarun Lake, Egyp ... t
Lake Qarun is an inland closed basin, located about 80 Kms south west of Cairo. It suffers from a serious water pollution problem which is due to uncontrolled solid and liquid domestic, in addition to agrochemical contamination and lack of sustainable wastewater management. The present study aimed to follow up the changes in the activities of liver enzymes (ALT, AST, and ALP) in fish (T. zillii and M. capito) Collected from different sites (east, middle and west) of the lake in four seasons. The results showed that in the two fish species at the studied sites, aspartate aminotransferase (AST) activity in the liver showed decreased values in comparison with the control fish samples collected from unpolluted site (fish farm) with percentage ranged between 10.86%-45.56%. Also, alanine aminotransferase (ALT) activity in the liver decreased significantly in comparison with the control fish samples with percentage ranged between 10.23%-54.07%. The alkaline phosphatase (ALP) activity in the liver decreased in comparison with the control fish samples with percentage ranged between 16.34%-49.54%.
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Research Article
Feb 28, 2019
The Effects of Different Stunning Techniques on Meat Quality of Brown Trout (Salmo Trutta Fario)
This study was conducted to assess the effects of various stunning methods on meat quality traits of Salmo trutta fario. A total of seventy five fish (1 year old, female/male) were exposed to one of the five stunning procedure: iced water, electrical shock, carbondioxide (CO2) saturated water, percussive stunning and asphyxia. Highest initial fillet pH was measured in CO2 group’s meat on the first day of the trial and the lowest initial pH belonged to asphyxia, but the difference among groups was not statistically significant (P>0.05). Significant relation was determined between pH and storage period of the fillets (P<0.01). No significant relation was obtained between killing methods and L* value of the meat. Killing method and storage period did not affect the water holding capacity and pH of the fillets. However; carbondioxide was thought to be the best method for better total volatile base nitrogen (TVBN) values; for better thiobarbituric acid-reactive substances (TBARS) of the meat, iced water method should be preferred.
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Research Article
Jan 18, 2019
Some Targeted Reference Points for Thin Lip Grey Mullet Liza Ramada Management in Bardawil Lagoon, ... North Sinai, Egypt
The evaluation and management of fisheries resources requires knowledge of spatial and temporal changes in the habitat-associations of fishes as well as studying the biology and dynamics of commercial fishes of that fishery. The thin lip mullet, L. ramada is one of the most important and high valued species in Bardawil lagoon, Egypt. Long term commercial catch statistics show a significant decrease in the commercial landings of grey mullet in Bardawil lagoon since 1995. By learning more about this species and protecting the habitat upon which it depends, we can ensure that this important valuable fish remains abundant. Age was determined based on scale’s readings of fish collected in May 2017 to December 2017 and in May 2018 to October 2018. Growth parameters, mortality rates, exploitation level as well as the critical lengths and ages were estimated. Based on yield per recruit analysis, the mullet fishery in Bardawil lagoon was found to be heavily exploited. The study suggested some applicable reference points for sustaining and optimizing the thin lip grey mullet yield in Bardawil lagoon.
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Research Article
Dec 31, 2018
Ovarian Development of the Penaeid Shrimp Penaeus Indicus (Decapoda): A Case for the Indian Ocean C ... oastal Waters of Kilifi Creek, Kenya
The Indian prawn Penaeus indicus, is one of the major commercial shrimp species globally. It is widely distributed in the Indo-West Pacific; from eastern and south-eastern Africa, through India, Malaysia and Indonesia to southern China and northern Australia. The species has been recorded to reach 22 cm, inhabiting depths of 100 m. Globally P. indicus is widely studied, although majority of the studies have focused on developmental stages between shallow waters and the deep seas. Studies indicate that development takes place in the sea before the larvae move into estuaries to grow, then return as sub-adults. However, studies on the maturity of this species in shallow waters and especially creeks and embayments are clearly lacking for the Kenyan coastline. This study was conducted in the Kilifi Creek, north coast Kenya, from the mouth at the Kilifi Bridge to past Kibokoni, some 5 km into the creek. Samples were collected from 6 landing sites. Morphometric and biological data including total length (TL, cm), carapace length (CL, cm), body weight (BW, g) and sex were recorded, and the specimens dissected to check for ovarian development and maturity. Ovarian development stages were determined from size, shape and colour of the ovaries, and through frequency analysis of the cortical granules. A total of 1,149 specimens were sampled from January to April, 2018. The catch mostly comprised of the 1.5 cm to 2.5 cm CL size class. However some individuals in the >4.0 cm CL size class were also recorded suggesting that some individuals still matured in the creeks although majority are known to migrate deep sea. Regression analysis showed a strong positive correlation between CL, and TL (r2=0.7548) and BW (r2=0.7497).The condition factor ranged from 0.19-0.94 indicating presence of both immature/spent (4.7%) and ripe individuals (95.3%) in good condition. Size frequency analysis of the ovary cortical granules displayed a poly-modal pattern with 2 peaks of immaturity and 3 peaks for developing and near-ripe respectively. The presence of spent stages as well as mature specimens in the creek waters indicated that apart from using these habitats as nursery and feeding grounds, some of the individuals might also be growing, maturing and spawning in the creek, calling for further studies into the assessment of the growth patterns and reproductive aspects of this species in the Kilifi Creek and other coastal waters.
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Research Article
Dec 31, 2018
Stomach Content Analysis and Concentrations of Chemical Pollutants in the Clymene Dolphin (Stenella ... Clymene, Gray 1846) from the Coastal Waters of Ghana
Stomach content analysis constitutes an important component of fisheries management, providing insight into fish feeding patterns and quantitative assessment of food habits. Thus, a study aimed at obtaining dietary information from stomach contents analysis of the most common by-caught dolphin species, Stenella clymene, beached from the coastal waters of Ghana, along the Gulf of Guinea was undertaken. The stomachs of 39 by-caught clymene dolphins landed at three fisheries landing beaches along the Ghanaian coast, were analyzed. A further study correlating the chemical contaminant load in tissues of Clymene dolphins to that of their preferred prey was undertaken. The stomach contents were generally composed of digested items. Fish, cephalopods and crustaceans were identified and represented a diversity of 12 species. On taxa level, fish was the most frequent (69%) and numerically the most important prey (46.57) followed by cephalopods (3.05) with crustaceans being present in trace amounts (1.55). However, both cephalopods and fish represented a more balanced share of the diet in biomass (45% and 51%) respectively. Thus, clymene dolphins off the coastal waters of Ghana appear to rely principally on both fish and cephalopods for food. Parasites also dominated the gut contents in relative abundance (48.83%). Prey items accumulated chemical contaminants at relatively the same concentrations (50%) as the blubber, liver and muscle of the clymene dolphins, confirming that food is the main source of exposure to contaminant load for marine mammals. With regards to quantitative analysis of prey species of cetaceans, this study of diet in clymene dolphins is the first recorded in this area.
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Research Article
Dec 28, 2018
Optimization of Spirulina Platensis Biomass and Evaluation of its Protective Effect Against Chromos ... omal Aberrations of Bone Marrow Cells
There are numerous studies investigating the effectiveness and potential clinical applications of Spirulina in treating several diseases. So, the present essay was designed to Cultivate Spirulina sp. in three different media; namely (modified commercial low cost Zarrouk medium (MS), Khul medium and Sea Water enriched medium), to compare Biomass concentrations (g/lDW) and optical density (OD) for 20 days, and phytochemical screening (Total phenolic, total flavonoids and Antioxidant activity) of the crude extract of all media with commercial Spirulina (dry product). In addition, examine possible potentials of Spirulina against hepatic intoxication induced by CCl4 in albino male mice. Results revealed that, methanolic extract recorded the highest values in modified Zarrouk’s medium (88.98 mg gallic acid equivalent/ml, 78.57 mg Rutin equivalent/ml and 82.04%) in Total phenolic, total flavonoids and Antioxidant activity respectively. Conclusively, Spirulina showed an ameliorating effect of CCl4 induced chromosomal aberrations of bone marrow cells; which proves the protective role of it against the chromosomal damage
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Research Article
Nov 07, 2018
Groundnut and Cottonseed Meals in Tilapia Juvenile Diets: Effects on Apparent Nutrient Digestibilit ... y, Short-Term Growth Performance, Feed Utilization and Carcass Composition
Oilseed by-products constitute a potential ingredient in fish feeds owing to their low cost, availability, and high protein contents. However, plant proteins tend to be deficient in essential amino acids limiting their utilization and incorporation in fish diets. This study evaluated the apparent nutrient digestibility, growth performance, feed utilization and whole-body composition of Nile tilapia fed diets containing 30% of cottonseed meal (CSM) or groundnut meal (GNM). The plant proteins corresponded to approximately 12% of dietary protein and replaced 42% to 46% of fish meal protein, respectively. The test diets; groundnut meal (GND30) and cottonseed meal (CSD30) were formulated to contain 32% crude protein and 14% crude lipid, with a gross energy density of 20 MJ/kg. A fish meal based diet served as a control (CD). Overall, the results showed that, with the exception of mean final body weight, weight gain (%), SGR and FCR did not differ among the diets but was highest in CD followed by GND30 and CSD30. The CSD30 resulted in significant reductions in protein and lipid digestibility, whereas nitrogen free extract digestibility was not affected in all diets. In general, 30% inclusion level of CSM and GNM are suitable replacements for fish meal in diets for Nile tilapia.
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Research Article
Oct 18, 2018
Mini review on Vibrio Infection-A Case Study on Vibrio harveyi Clade
Pathogens respond to host immunity by secreting virulence factors which facilitate their proliferation and survival in host. Most bacteria including Vibrio harveyi coordinates gene expression by cell-cell communication termed quorum sensing. Quorum sensing (QS) involves the production, detection, and response of molecules to extracellular signals to enable bacteria monitor population density and induce specific genes in response to changes in cell number. Quorum sensing systems regulate virulence, bioluminescence, biofilm formation and antibiotic production which are necessary factors to induce infection. V. harveyi interacts inter-specially and intra-specially to overcome host defences and cause detrimental infections to a wide range of aquatic host. This review reflects the mechanism aiding infection in Vibrio species, considering V. harveyi clade.
