Role and use of evidence in policymaking: an analysis of case studies from the health sector in Nigeria.

Background Health policymaking is a complex process and analysing the role of evidence is still an evolving area in many low- and middle-income countries. Where evidence is used, it is greatly affected by cognitive and institutional features of the policy process. This paper examines the role of different types of evidence in health policy development in Nigeria. Methods The role of evidence was compared between three case studies representing different health policies, namely the (1) integrated maternal neonatal and child health strategy (IMNCH); (2) oral health (OH) policy; and (3) human resource for health (HRH) policy. The data was collected using document reviews and 31 in-depth interviews with key policy actors. Framework Approach was used to analyse the data, aided by NVivo 10 software. Results Most respondents perceived evidence to be factual and concrete to support a decision. Evidence was used more if it was perceived to be context-specific, accessible and timely. Low-cost high-impact evidence, such as the Lancet series, was reported to have been used in drafting the IMNCH policy. In the OH and HRH policies, informal evidence such as experts’ experiences and opinions, were reported to have been useful in the policy drafting stage. Both formal and informal evidence were mentioned in the HRH and OH policies, while the development of the IMNCH was revealed to have been informed mainly by more formal evidence. Overall, respondents suggested that formal evidence, such as survey reports and research publications, were most useful in the agenda-setting stage to identify the need for the policy and thus initiating the policy development process. International and local evidence were used to establish the need for a policy and develop policy, and less to develop policy implementation options. Conclusion Recognition of the value of different evidence types, combined with structures for generating and using evidence, are likely to enhance evidence-informed health policy development in Nigeria and other similar contexts

Water Quality of Trickling Biological Periwinkle Shells Filter for Closed Recirculating Catfish System

Studies were carried on the design, efficiency and economics of trickling biological periwinkle shells filter in recirculating aquaculture systems for catfish production. The designed biofilter and other system components were constructed, assembled and commissioned for pilot catfish production. The system with the designed biofilter served as the treatment system, while that without biofilter served as the control system. Data were collected daily (except for BOD5) on water quality parameters such as total ammonia-nitrogen (TAN), nitrite-nitrogen, unionized ammonia–nitrogen (UAN), pH, dissolved oxygen (DO), surface water temperature, secchi transparency, total alkalinity, Chloride content, total hardness  free carbon dioxide and biochemical oxygen demand (BOD). The Total length and weight of fish stocked in the treatment and control systems were measured at the beginning of the study and subsequently every four weeks. Results showed that total ammonia–nitrogen for the treatment system ranged from 0.00 to 4.00 ppm, with a mean of 1.26±0.92 ppm, while that of the control varied from 0.00 to 6.50 ppm, with a mean of 2.23±1.80 ppm. The nitrite–nitrogen values of the treatment system ranged from 0.00 to 1.80 ppm, with a mean of 0.67±0.40 ppm, while that of the control system ranged from 0.00 to 2.50 ppm, with a mean of 1.18±0.79 ppm. The un-ionized ammonia–nitrogen values for the treatment system varied from 0.000 to 0.022 ppm, with a mean of 0.007±0.006 ppm, while that of the control system ranged from 0.000 to 0.036 ppm, with a mean of 0.015±0.016 ppm. Results of fish growth showed that final fish weight for the treatment system ranged from 287.50 to 1280.00 g, with a mean of 765.35±259.24 g, while that of the control ranged from 50.00 to 800.00 g, with a mean of 490.31±185.65 g. Mean value of final fish weight stocked in the treatment system was significantly (p<0.05) higher than that of the control. Apart from total hardness, nitrite–nitrogen and unionized ammonia-nitrogen the mean values of all other water quality parameters for the treatment system were not significantly (p>0.05) different from that of the control system. It is therefore concluded that the trickling biological periwinkle shells filter provided adequate biological water treatment for closed recirculating catfish system.       Keywords: Water quality, Periwinkle shells biofilter, recirculating catfish syste

The Efficiency of Periwinkle Shells Filter as Biofilter Medium in Closed Recirculating Catfish Systems

Studies were carried out for twelve 12 weeks on the design, efficiency and economics of biofilter using periwinkle, Tympanotonus fuscatus, fuscatus, var radula: shells as biofilter medium in recirculating aquacuture system (RAS). The designed biofilter and the other designed system components were constructed, assembled and commissioned for a pilot mud catfish (Clarias gariepinus) production. The system with the designed biofilter served as the treatment system, while the control system had no biofilter. The efficiency of the biofilter was computed daily using the total ammonia-nitrogen (TAN) method. The biofilter efficiency indicators water quality, nitrite-nitrogen, unionized ammonia-nitrogen and total ammonia-nitrogen (TAN) of treatment and control systems were monitored daily except biochemical oxygen demand (BOD). The total length and weight (WT) of fish stocked in the treatment and control systems were measured at the beginning of the study and subsequently every four weeks. Results showed that biofilter efficiency of the treatment system varied from 0.00 to 100.00%, with a mean of 54.78+23.95%. The value of TAN for the treatment system ranged from 0.00 to 4.00 ppm, with a mean of 1.26+0.92 ppm, while that of control system ranged from 0.00 to 6.80 ppm, with a mean of 2.23+1.80 ppm. The nitrite-nitrogen value for the treatment system ranged from 0.00 to 1.80 ppm with a mean of 0.66+0.49 ppm, while that of the control ranged from 0.00 to 2.50 ppm with a mean of 1.18+0.79 ppm. The unionized ammonia-nitrogen value varied from 0.000 to 0.022 ppm, with a mean of 0.007+0.006 ppm for the treatment system, while that of the control ranged from 0.000 to 0.036 ppm with a mean of 0.015+0.016 ppm. Final fish weight for the treatment system ranged from 287.50 to 1280.00 g, with a mean of 765.35+259.24 g, while that of the control ranged from 50.00 to 800.00 g with a mean of 490.31+185.69 g. Results of statistical analysis showed that mean values of nitrite-nitrogen, unionized ammonia-nitrogen and final fish weight obtained for the treatment system were significantly (p<0.05) lower than that of the control system. Mean values of TAN, surface water temperature, pH, chloride and other water quality parameters for the treatment system were not significantly (p>0.05) different from that of the control. It was concluded, therefore, that periwinkle shell was suitable as natural biofilter medium in closed recirculating catfish systems. Keywords: Periwinkle shells, catfish, aquaculture, biofilter medium, closed recirculating syste

The design of trickling biological periwinkle shells filter for closed recirculation catfish systems

The design efficiency and economics of biofilter in reirculating aquaculture systems using local material as biofilter was carried out for 12 weeks. The type of trickling biofilter selected was vertical flow. The local, natural material selected as biofilter medium was periwinkle shells. The designed biofilter and other system components were constructed, assembled and commissioned for pilot fish production using catfish-Clarias gariepinus. The system with the designed biofilter served as the treatment system, while the system without biofilter served as the control system. Results of the biofilter design were 2.0 m depth, 150 m2 surface area, 226 m2/m3 specific surface area and 0.35 m2 cross sectional area. The specifications of the fish tank were 0.29 m radius, 0.90 m height, 0.21 m3 volume and 0.10 m free board. The results of the design of the sedimentation tank were 1.40 m length, 1.0 m width, 1.0 m depth, 2.0 hours detention time, 0.42 mm/sec settling velocity and 600 angle of inclination of the settling plates. The lift pump selected had the following specifications, 0.50 Hp power, 2.10 m3/hr discharge and 35.00 m head. The diameter of the perforation on the bottom of the distribution plate was 6.00 mm, while clearance was 0.3 m. The selected system recirculation rate was 10 times per hour, while the selected system recirculation ratio was 90% per day. Data from pilot fish production showed that mean values of final total length (TL) and weight of fish stocked in the treatment system were significantly (p<0.05) higher than that of the control. The result of the total ammonia-nitrogen (TAN), for the treatment system ranged from 0.00 to 4.00 ppm with a mean of 1.26+0.92 ppm, while that of the control varied from 0.00 to 6.80 ppm with a mean of 2.23+1.80 ppm. The nitrite-nitrogen values for the treatment system ranged from 0.00 to 1.80 ppm with a mean of 0.66+0.49 ppm while that of the control ranged from 0.00 to 2.50 ppm with a mean of 1.18+0.79 ppm. The unionized ammonia-nitrogen value (UAN) for the treatment system ranged from 0.000 to 0.022 ppm with mean of 0.007+ 0.006 ppm, while that of the control system ranged from 0.000 to 0.036 ppm, with a mean of 0.015+0.016 ppm. The mean values of nitrite-nitrogen and unionized ammonia-nitrogen for the treatment systems were significantly (p<0.05) lower than that of the control, while TAN mean value in the treatment system was not significantly (p>0.5) lower than that of the control system. Result of biofilter efficiency ranged from 0.00 to 100.00%, with a mean of 54.78+23.95%. Data on other water quality parameters such as DO, pH, temperature, BOD5, Seechi transparency, total alkalinity, free carbon dioxide, chloride, etc. in the treatment system were not significantly (p>0.05) different from that of the control system. We concluded that periwinkle shell is a suitable trickling filter medium for closed recirculation catfish system.Keywords: Periwinkle shells medium, closed recirculating catfish system, biofilter designInternational Journal of Natural and Applied Sciences, 6(3): 272-280, 201