Effects of spices on the chemical properties of hot-smoked catfish (Clarias gariepinus)

Effect of spices on the chemical properties of hot-smoked catfish (C.gariepinus) was examined. The experimental design was complete randomized design (CRD) with the treatments been the variously spiced hot-smoked catfish (garlic, ginger, garlic-ginger homogenate spiced and the control without spices). Proximate and mineral content analyses were carried out using standard experimental procedures. There exist significant differences (p<0.05) in the percentage moisture and crude protein content with smoked catfish without spices having the highest moisture content with mean value 6.18 ~c 0.13 and 79.44 ~c 0.13 respectively which could be as a result of the increase in the fibre content of the spiced fish products which is a function of fibre content of the spices applied to the fish products. Similar trend was also observed for the lipid and ash contents the fish products. There exist significant differences (p<0.05) in the mineral content preseent in the various fish products with the exception of magnesium. The products are rich in calcium and other minerals with garlic-ginger homogenate spiced product having the highest level of calcium (0.980 ~c 0.02)

Effects of length of delay after slaughter (Lodas) on raw catfish Clarias gariepinus (Burchell, 1822)

The effect of delay after slaughter on microbial quality, proximate composition and sensory scores of raw catfish, Clarias gariepinus was evaluated. A total of 52 live catfish (average weight 700.0~c7.0g) were used for the experiment. Ten freshly slaughtered fish samples each were selected for organoleptic assessment at 0, 4, 8 and 12 hours post-slaughter, while three fish samples each were selected for chemical and microbial analyses. Microbial load on fish samples increased significantly (P< 0.05) with increase in length of delay after slaughter, LODAS. Bacteria isolated included Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus spp and Staphylococcus aureus. Percent protein and ash contents of fish samples increased with increasing LODAS, while moisture content decreased and lipid was not affected. It was observed that raw C. gariepinus retained most of its physical attributes up to 4 hours post-slaughter. These quality attributes except colour and odour of gills, deteriorated significantly (P < 0.05) at every successive four-hour post-slaughter interval. Significant negative correlation existed between LODAS and sensory quality of raw fish (eyes, r = -0.966, P < 0.05; gills, r = -0.980, P < 0.05; skin, r = -0.998, P < 0.01; and odour, r = -0.994, P < 0.01). This study established that quality of raw C. gariepinus deteriorated with increasing LODAS and that raw C. gariepinus was not totally unacceptable when delayed for 12 hours after slaughter at ambient temperatures

Impact of feeding diets containing Luffa cylindrica seedmeal on the variable cost of production of African catfish, Clarias gariepinus (Burchell 1822)

This study investigates the use of Luffa cylindrica seed meal as soybean replacer in the diet of Clarias gariepinus. Five isonitrogenous diets containing soybean meal which was replaced by Luffa cylindrica at a rate of 0, 15,30,45 and 60% were made. The diets without Luffa cylindrical seed meal served as the control. Experimental diets were assigned randomly to the tanks and each group of fish was fed 5% body weight in equal proportion per day. The fish fed diet 1 had the highest incidence of cost, while the fish fed diet 4 had the lowest incidence of cost. There was no significant difference (P>0.05) in the incidence of cost of producing 1kg fish with the different dietary treatments. The fish fed at diet 4 had the highest profit, while the fish fed at diet 1 had the lowest profit. There was no significant difference (P>0.05) in the profit margin of producing 1kg fish with the different dietary treatments. The incidence of cost showed that it was cheaper to produce 1kg of fish with Luffa cylindrical seed meal because feeding the fish with the diet (control and tests diets) left some profit margin

Effects of soaking on artisanal polyvinyl-alcohol (PVA) synthetic fishing twine in freshwater, brackish and marine waters

Elongation (cm) and breaking-load (kgf) effects on artisanal Polyvinyl-Alcohol (PVA) synthetic twine of diameters 4mm, 6mm, 8mm and I0mm soaked in fresh (0.4ppt), brackish (25ppt) and marine (37ppt) waters for 112 days were investigated. Chemical (burning) test was carried out to identify the experimental white twine as PVA, among other six locally synthetic twines (Klust, 1973). A tensile-strength gauge machine (0-200kg) was used to test the mechanical strength properties of PVA twine diameters in dry (control) and wet states. Results indicated that elongation and breaking-load of the specimens were significantly (P<0.05) influenced by R- Tex. Elongation and breaking-load were observed to be highest in dry twine 10mm with means of 20.75a ~c 1.05 and 140.00a ~c 5.37 respectively, higher in twine 10mm (with means of 20.40b ~c 3.50 and 131.75b ~c 5.l0 respectively) soaked in freshwater and lowest in twine 4mm (means of 1 4.83fg ~c 0.31 and 33.70h ~c 1.00 respectively) soaked in marine water. Twines of the same diameter (l0mm, 8mm, 6mm & 4mm) soaked in fresh water (0.7ppt) has highest significant (p<0.05) elongation and breaking load than those soaked in brackish (0.25ppt) and marine water respectively. The thicker the PVA twine diameter, the higher the significant (p<0.05) elongation and breaking load, which could lead to increased mesh sizes of fishing nets constructed from such twines. Fishermen are therefore encouraged to air-dry their fishing nets or gears when not in used to extend the shelf-life

Microbial load on smoked fish commonly traded in Ibadan, Oyo State, Nigeria

The microbial load on smoked fish sold in Ibadan, Oyo State was studied. 64 of 4 different fish species (Mackerel (Scomber scombrus), Sardine (Sardinela eba), Panla (Gadus morhua) and Cat fish (Clarias gariepinus)) were sourced from five different market locations. The microbiological analysis was done using standard microbiological procedures. The bacterial count of fish sampled from Ojo market was the highest (0.35±0.11 x 103 CFU/g) while the bacteria count of the fish sample from Bodija market was the lowest (0.07±0.04 x 103 CFU/g). There was no significant difference (p&gt;0.05) in the microbial load of the various fish species sold within Ibadan metropolis as well as fish sampled from various market locations in Ibadan metropolis. Bacterial isolated on smoked fish studied were: E. coli, Salmonella spp, Klebsiella spp, Staphylococcus aureus, Aerosomonas spp, Pseudomonas spp, Vibrio spp, Serratia spp, Chromobacterium spp, Enterobacteria spp and Shigella spp. While the following fungi were isolated from the study: Aspergillus flavus, Penicillium spp, Fusarium oxysporum, Trrichoderma spp and Ceotrichium albidium. Fish species sold in different markets within Ibadan metropolis is fit for human consumption. Caution should be exercised in consuming smoked-dried fish displayed openly, reheating may be necessary to activate such micro-organisms before consumption.Keywords: bacteria, fungi, market, fish specie

Assessment of fishing gear and crafts utilized by fishermen in Eleyele Lake, Ibadan, Oyo State

The study was conducted to assess the evolution of fishing gears and crafts utilized by fishermen in Eleyele lake reservoir in lbadan Nigeria. Data were collected from thirty fishermen using a structured questionnaire. The data obtained were analyzed using counts and chi-square. Majority (56.7%) of the respondents were married, more of respondents were male (56.7%). Fish and fishing gear construction activities in the study area is dominated by youth. More of the respondents were Christians and few were Muslims (36.7%). There was significant relationship between the type of fishing gear use (modern and traditionl) and the time spent to catch fish as well as the quantity of fish caught. The result also revealed that traditional fishing gears such as bamboo trap, hook and line and cast net were been used by the fisher folks but were later changed to modern fishing gear. However, the effectiveness and efficiency of the modern fishing gear is being hampered by aquatic weed covering the surface of the water

Effect of replacing soybean meal with water melon (Citrullus lanatus) seed meal on the growth, feed utilization and body composition of Nile tilapia (Oreochromis niloticus)

The nutritive potential of watermelon (Citrullus lanatus) seedmeal as dietary protein source in the diet of Nile tilapia (Oreochromis niloticus) using growth performance and nutrient utilization were evaluated in a 56 day feeding trial. One hundred and fifty tilapia fingerlings of average weight 6.12±0.05g were acclimatized for a week, weighed and allotted into five dietary treatments; containing 0, 15, 30, 45 and 60% Citrullus lanatus replacement levels with soybean meal respectively. The diets (35% crude protein and 10% lipid) were isonitrogenous and isolipidic. Each treatment was replicated three times with ten fish per replicate. Fish were fed 5% body weight on two equal proportions per day to determine weight gain, percentage weight gain, specific growth rate, food conversion ratio, protein efficiency ratio and net protein utilization. The result from the study indicated that there was no significant (p&gt;0.05) differences in the FCR and PER between the fish fed control diets and the fish fed test diets