Keynote address on production, utilization and marketing in fisheries status and opportunities

Fish production from Nigeria comes mainly from 3 sources, namely - artisans engaged in either part-time or full-time fishing, commercial trawlers fishing in inshore and offshore waters, and fish farming in enclosures (ponds, tanks and raceways). An account is given of the current situation in Nigeria, considering over exploitation of fish, the fish's environment, fish utilization, and fish marketin

Strategies for the establishment of profitable fish farms in Nigeria

Cost projections for the establishment of a fish farm in Nigeria was conducted. It is shown that fish farming should be a lucrative venture. However, many private fish farms are not making the desired profits because of a variety of problems. Besides managerial incompetence, availability of fingerlings for stocking in the ponds is shown to be a serious handicap to the success of investments in a fish farm. It is suggested that where the funds are available, each farm should be equipped with facilities for raising its needs of fingerlings. Since useful capital would be involved and knowledgeable experts to run the hatcheries are few, it is recommended that fish farms within a state or adjacent states should combine to establish viable cooperative hatcherie

Climate change: implications for fisheries and coastal aquaculture

A keynote address at the 25th annual conference of the Fisheries Society of Nigeria. The paper presented evidence of climate change in the past and discussed the issue of global warming in the past, present and future. The Greenhouse effects are some of the topics discussed. Discussed in greater detail is the Nigerian situation in the global warming and climate change. The potential impacts on aquaculture has been enumerated. The paper is concluded by given suggestionswhich mitigate the impact of climate change and called on the Federal Ministry of Environment to strengthen research and other arms of government to create a strong synergy to work towards ameliorating the impact of climate change in the country

The influence of diets and body manipulations on the growth of African prawn Macrobrachium vollenhovenii (Herklots)

Live African prawns Macrobrachium vollenhovenii were collected from Asejire reservoir (Nigeria) by trapping. After acclimatization, the prawns were differently amputated: some had their eye-stalks cut; some had their chelae cut; some had both eyestalks and chelae cut while some were intact which served as the control. Each set was placed under different levels of crude protein viz 15%; 20%; and 25%. Weekly weight changes were monitored. Results obtained were subjected to statistical analysis including analysis of variance (ANOVA). The results showed that prawns fed with 20% crude protein had the best growth rate. Specimens with the eyestalk and chelae removed also showed superior growth when compared with the others. Specimens that had their eyestalks removed were able to feed for 18 hours in the day while those with intact body fed for 6 hours during the same period. The amputation of the chelate appendages reduced considerably the cannibalistic urge in the prawns. This enabled a high number of prawns to be grown in the experimental tank

Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria

Introduction: This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Methodology: Minimum inhibitory concentration (MIC) distributions of the isolates were determined using the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. Results: A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resistance was: tetracycline 81%, sulphamethoxazole 67%, streptomycin 56%, trimethoprim 47 %, ciprofloxacin 42%, ampicillin 36%, spectinomycin 28%, nalidixic acid 25%, chloramphenicol 22%, neomycin 14%, gentamicin 8%, amoxicillin-clavulanate, ceftiofur, cefotaxime, colistin, florfenicol and apramycin 0%. Resistance genes found among the isolates include bla-TEM (85%), sul2 (67%), sul3 (17%), aadA (65%), strA (70%), strB (61%), catA1 (25%), cmlA1 (13%), tetA (21%) and tetB (17%). Class 1 and 2 integrons were found in five (14%) and six (17%) isolates, respectively, while one isolate was positive for both classes of integrons. Seven out of eight isolates with resistance to ciprofloxacin and MIC ≤ 32 mg/L to nalidixic acid contained qnrS genes. Conclusions: Our findings provided additional evidence that the poultry production environment in Nigeria represents an important reservoir of antibiotic resistance genes such as qnrS that may spread from livestock production farms to human populations via manure and water.</jats:p

In vitro studies on the sensitivity pattern of Plasmodium falciparum to anti-malarial drugs and local herbal extracts

Background: The resistance of human malaria parasites to anti-malarial compounds has become considerable concern, particularly in view of the shortage of novel classes of anti-malarial drugs. One way to prevent resistance is by using new compounds that are not based on existing synthetic antimicrobial agents. Results: Sensitivity of 100 Plasmodium falciparum isolates to chloroquine, quinine, amodiaquine, mefloquine, sulphadoxine/pyrimethamine, artemisinin, Momordica charantia (‘Ejirin’) Diospyros monbuttensis (‘Egun eja’) and Morinda lucida (‘Oruwo’) was determined using the in vitro microtest (Mark III) technique to determine the IC50 of the drugs. All the isolates tested were sensitive to quinine, mefloquine and artesunate. Fifty-one percent of the isolates were resistant to chloroquine, 13% to amodiaquine and 5% to sulphadoxine/pyrimethamine. Highest resistance to chloroquine (68.9%) was recorded among isolates from Yewa zone while highest resistance to amodiaquine (30%) was observed in Ijebu zone. Highest resistance to sulphadoxine/pyrimethamine was recorded in Yewa and Egba zones, respectively. A positive correlation was observed between the responses to artemisinin and mefloquine (P<0.05), artemisinin and quinine (P<0.05) and quinine and mefloquine (P<0.05). A negative correlation was observed between the responses to chloroquine and mefloquine (P>0.05). Highest anti-plasmodial activity was obtained with the ethanolic extract of D. monbuttensis (IC50 = 3.2nM) while the lowest was obtained from M. lucida (IC50 =25nM). Conclusions: Natural products isolated from plants used in traditional medicine, which have potent anti-plasmodial action in vitro, represent potential sources of new anti-malarial drugs

Entomopathogenic fungi in population of Zonocerus variegatus (l) in Ibadan, south west, Nigeria

Field survey of population of Zonocerus variegatus revealed a high fungal incidence of 76% when Sporulation tests were carried out on grasshoppers cadaver. Eight fungi with differing incidence rates were isolated. These are Fusarium sp. (8%); Beauveria bassiana (18%); Metarhizium sp. (20%); Aspergillus flavus (10%); Penicillium sp. (13%) Aspergillus niger (14%); Mucor sp. (13%) and unidentified fungus (4%). Fungal isolates virulence bioassay response showed that B. bassiana had the highest lethal time (LT50) of 2 days. Metarhizium sp with LT50 of 5 days was selected in lieu of A. niger which does not prove to be pathogenic to grasshoppers. The results were discussed in relation to the ecology of fungal pathogens of the variegated grasshopper and their possible role in control of Z. variegatus in the agroecosystem of south west, Nigeria. Key words: Fungal ecology, entomopathogenic fungi, Zonocerus variegatus infection incidence. African Journal of Biotechnology Vol.3(8) 2004: 382-38

Growth pattern and structural nature of amylases produced by some Bacillus species in starchy substrates

The growth pattern and microbial biomass formed during metabolic activities of the Bacillus species on starchy substrates was determined. The result showed that the strains B. subtilis (WBS), B. licheniformis (WBL) and B. coagulans (MBC) generally had high growth rate. B. circulans (SBC) and B. coagulans (WBC) has specific affinity for growth and some enzymatic activity on corn starch medium compared with other lower growth observed in B. polymyxa (WBP) but higher enzyme production. The amylolytic Bacillus species obtained utilized white corn starch substrate as a sole carbon source as well as soluble starch. The amylase production values range from 0.022 x 102 unit/cfu in B. circulans (WBC) to 0.912 x 102 unit/cfu in B. licheniformis (WBL) for corn starch, and 0.01 x 102 unit/cfu in both B. megaterium (SBG) and B. licheniformis (SBL) to 0.693 x 102 unit/cfu in B. subtilis (WBS) for soluble starch.Keywords: Activity, Bacillus, enzymatic, metabolic, starchy, substrat