A pot experiment was conducted to investigate the effect of vermicompost and chemical fertiliser on the growth of yield and nutrient content of Ipomoea aquatic and Basella alba during the period of 14th May to 13th July, 2013. The experiment was laid to fit a completely randomized design (CRD) with three treatments [control (T0), vermicompost (T1) and chemical fertiliser (T2)] each having three replications for each plant. After plant harvesting, the laboratory investigation was carried out in the Soil, Water and Environment Discipline, Khulna University, Khulna, Bangladesh. Yield contributing characters like plant height, stem length, rooting depth, number of leaves, fresh weight and dry weight were significantly (P < 0.05) influenced by different (vermicompost and chemical fertiliser) treatments. All yield character was decreased in order to T1>T2>T0, except rooting depth for the both plants Ipomoea aquatica and Basella alba. The causes of variation may due to the nutrient availability in soil. In addition, the nutrient (P, K and S) content of both plants varied significantly (P < 0.05) with the treatments T1>T0>T2. From the experiments it has been observed that the effect of vermicompost and chemical fertiliser on the growth of yield and nutrient content of Ipomoea aquatic and Basella alba were T1>T2>T0 and T1>T0>T2, respectively. The highest yield was found for the vermicompost treatment (T1) due to the nutrient availability of the soil.
Fish is a highly perishable product and major causes of spoilage are autolysis, bacterial decomposition and oxidative rancidity in fatty fishes. One of the cheapest form of fish preservation is smoking. Although deteriorative changes occur after smoking, the need to further freeze to extend the shelf life of the fish product is therefore expedient. Deteriorative changes and shelf-life of cold smoked Clarias gariepinus were studied at ambient temperature and under cold storage temperature of -250c for a period of twelve weeks. The organoleptic analysis, chemical analysis: peroxide value (P.V); free fatty acids (FFA) and total volatile base (TVB) and bacterial count/flora isolation were studied to determine the rate of spoilage. A total of sixty (60) live samples of Clarias gariepinus, average weight 200-300 g and cold smoked for 18 hours at a temperature of 300C were used for this experiment.
significant differences (P<0.05) were found in proximate composition values of fresh, cold smoked and fish stored for twelve weeks. The chemical assessment and bacteriological parameters also differed significantly. Higher values were recorded for all measured parameters at ambient temperature as compared to cold storage temperature of -250c. There was an increase in the crude protein (C.P) level due to loss of moisture during smoking. Fat content increased as a result of gradual oxidative rancidity of poly unsaturated fatty acids from zero weeks of initially smoked Clarias gariepinus to the 12th week. Total Volatile Base-Nitrogen values, Peroxide values (PV), Free Fatty Acid and Bacterial count values also increased.
Seven (7) species of bacteria were identified from the cold stored cold smoked fish while nine (9) species were identified at the ambient stored smoked fish, this showed that spoilage condition is faster in ambient storage rather than in the cold storage. There was significant difference (P<0.05) in the number of bacteria isolated under ambient condition (9 species) and cold storage (6 species) cold smoked Clarias gariepinus. Based on this, there is need for further cold storage of cold smoked Clarias gariepinus in order to increase its shelf-life.
Vitamin C is a micronutrient necessary for the proper functioning of fish body. It is needed for absorption of ions and nutrients and its deficiency in fish is evident mostly by structural deformities such as curvature of the spine, broken skull and hemorrhage. It is therefore important to incorporate Vitamin C into fish diets at recommended dosages for active uptake. It is a major component in the synthesis of collagen which enables fish to maintain its structural and skeletal integrity. During feed formulation, the use of phosphorylated form should be used for optimal stability in feeds because a great portion of the micronutrients can be lost during feed processing and storage. Based on all these facts, research is continuously being carried out to study the beneficial effects and how it can be adequately composed in fish feeds to meet the particular requirements of fish.
Feeding of fish with artemia involves a lot of financial investment and it is therefore essential to source for a cheap and yet adequate source of production of life food for fish. This research compares the effects of different organic manures on zooplankton production in culture systems. The manures used were Poultry droppings, Cow dung, Cassava peels and a Control (without manure) and were added into the culture systems at the rate of 57 mg dm-3 of water. The research was carried out for a period of twelve weeks after then identification and counting of species of zooplankton was done by taking 1ml/day from culture systems and water quality parameters in each culture system was also determined once daily. Zooplankton observed were Filinia sp. and Brachionus sp. belonging to Rotifera, Moina sp. and Daphnia sp. belonging to Cladocera and Cyclopods belonging to Copepoda. Moina sp. accounted for 11751 out of the total abundance of zooplankton irrespective of culture system while Daphnia sp. accounted for 11683, Cyclopods 7332, Filinia sp. 5594 and the least was Brachionus sp. accounting for 5230 total zooplankton. Poultry droppings stimulated the highest production having a total of 18908 zooplankton, followed by Cow dung (11845), Cassava peels (9505) and the least was from the Control (1332). The mean values for temperature were 27.4°C for poultry droppings, 27.1°C for Cow dung, 27°C for Cassava peels and 27.3°C for the Control. pH recorded 7.5 for Poultry droppings, 7.0 for Cow dung, Cassava peels 6.9 and 7.1 for the Control. Dissolved oxygen was 5.0 mg dm-3 throughout the culture systems. Ammonia recorded 0.9 mg dm-3 for Poultry droppings, 0.4 mg dm-3 for Cow dung, 0.0 mg dm-3 was recorded for Cassava peels and Control. Nitrite was 3.5 mg dm-3 for Poultry droppings, 0.25 mg dm-3 in Cow dung, 0.5 mg dm-3 in Cassava peels and 0.1 mg dm-3 in Control. Nitrate was 80 mg dm-3 for Poultry droppings, Cow dung was 22.5 mg dm-3, 25.0 mg dm-3 was Cassava peels while 12.5 mg dm-3 was the Control. ANOVA results showed significant relationship (P<0.05) between the number of zooplankton produced in relation to the various types of Manures applied. In conclusion, Poultry droppings gave the best result and Cassava peels can also serve as an option in areas where poultry droppings are in short supply. The Control gave the poorest result and this clearly indicates that fertilization is essential in culture systems.
Survey of insects on sweet potato, Ipomoea batatas (Lam) was conducted in Southern Nigeria during two cultivation periods within a season, March-July and August-December, to identify key pests and beneficial species that can be exploited in future biocontrol programmes. The recorded insects consisted of thirty four different species and approximately 80% were defoliators. The Order Orthoptera had the highest number of individual species (29.4%), followed by Coleoptera and Lepidoptera pests in equal percentages (23.5%). Members from these Orders were the key pests and they were responsible for the most significant damage to the foliage and the tuber. Specifically, economic damage was caused by sweet potato butterfly (Acraea acerata), leaf folders (Brachmia and Helcystogramma spp), and sweet potato army worms (Spodoptera spp) and white plume moths (Pterophorus pentadactyla) and they are considered as potential targets of control programmes. The beneficial insects (5.9%), comprised of Adonis lady beetle (Hippodamia variegate), Transverse lady beetle (Coccinella transversalis) (Coleoptera: Coccinellidae), Black cockroach-wasp (Dolichurus spp), Cicada killer (Sphecius speciosus) and Praying mantids (Mantis religiosa) (Mantodea: Mantoididae). About 80-100% damage to foliage was recorded, indicating a severe pest pressure on sustainable sweet potato production under organic system in Southern Nigeria and the need to develop ecologically adaptable management approaches.