Browsing by Author "Munubi, Renalda N"

Now showing 1 - 5 of 5

Comparative evaluation of water quality parameters and growth performance of sex-reversed Nile tilapia (Oreochromis niloticus) raised in two different climatic conditions in Tanzania
(2020-06) Komba, Emma A; Munubi, Renalda N; Chenyambuga, Sebastian W
A study was done to compare water quality parameters, growth and production performance of Sexreversed Nile tilapia (Oreochromis niloticus) cultured in two districts of Tanzania, which experience different climatic conditions (cold and moderately warm). Fingerlings (1.00 g average weight) were stocked in earthen ponds (2 fish/m3), then raised for six months. Fish were fed twice daily and ponds were inorganically fertilized fortnightly. Measurements of water quality parameters and fish growth parameters (weight, length and width) were done biweekly. The results revealed significant differences on various water quality parameters; including temperature, salinity, conductivity and alkalinity between the two districts (p≤0.05). Mean growth rate, specific growth rate, mean final weight, estimated annual yield and Food Conversion Ratio were significant better for fish grown in warm than those in cold climate (p≤0.05). It is concluded that, fish growth and water quality parameters are better in warm than cold condition.
Comparison of body length-weight relationship and condition factor for Nile tilapia (Oreochromis niloticus) cultured in two different climatic conditions in Tanzania
(2020-04) Komba, Emma A; Munubi, Renalda N; Chenyambuga, Sebastian W
This study compared length-weight relationship and condition factor of male Nile tilapia raised in two districts experiencing different climatic conditions in Tanzania, Mbarali and Mufindi. Fish were raised for six (6) months and measurements were done biweekly. The results suggests negative allometric growth pattern (b < 3) for the fish grown in both experimental locations. The “b” values for the lengthweight relationships were 2.87 and 2.94 in Mbarali and Mufindi, respectively. The correlation coefficient and coefficient of determination indicated strong relationship (>99%) between length and weight of the fish. The condition factor (K) ranged from 2.74 to 3.50 in Mbarali and 1.96 to 2.40 in Mufindi, throughout the experimental period. Significantly higher condition factor was observed for fish grown in Mbarali (3.168 ± 0.056) than those in Mufindi (2.166 ± 0.056). It is concluded that, the climate of Mbarali provides better conditions for growth of fish than that of Mufindi.
Effects of inorganic fertilizer application and supplementary feeding on water physico-chemical parameters, growth performance and yield of Nile Tilapia (Oreochromis niloticus) cultured in earthen ponds
(International Journal of Fisheries and Aquatic Research, 2020) Shabani, Salimu; Munubi, Renalda N; Chenyambuga, Sebastian W; Madalla, Nazael A.; Quagrainie, Kwamena; Frimpong, Emmanuel; Egna, Hillary
This study was carried out for 180 days to assess the growth performance, water physico-chemical parameters, yield and profitability of Nile tilapia (Oreochromis niloticus) culture in earthen ponds. The fish were reared in nine earthen ponds with average size of 177 m 2 and subjected to three treatments i.e. pond fertilization alone (T 1 ), concentrate feeding alone (T 2 ) and a combination of pond fertilization plus concentrate feeding (T 3 ). Sex- reversed Nile tilapia fingerlings were stocked at a density of 3 fish/m 2 . For T 1 and T 3 , urea and Diammonium phosphate (DAP) fertilizers were applied in pond water weekly at a rate of 3 g/m 2 and 2 g/m 2 , respectively. For T 2 and T 3 the fish were fed a diet containing 25.1% crude protein (CP) at a rate of 5% and 2.5% of body weight, respectively. Pond water physico-chemical parameters were measured weekly. A total of 30 fish from each pond were harvested biweekly and individually measured for body weight and length. Dissolved oxygen (DO), pH, Secchi disk reading, conductivity, salinity, phosphorous, nitrate and alkalinity differed (p ≤ 0.05) but temperature did not differ (p > 0.05) among treatments. In all treatments the water quality parameters were within the acceptable range for tilapia culture. Within a 24 hours period, DO, pH and temperature were highest at 1500 hours and lowest at 0600 hours. The fish reared under T 3 showed higher (p < 0.05) body weight gain (194.1 ± 4.5 g), growth rate (GR) (1.5 ± 0.1 g/day), estimated yield (13 065 ± 458 kg/ha/year) and gross margin (12 364.41 ± 1 376.75 USD/ha) than those under the other treatments. The FCR was higher (4.1 ± 0.3) for the fish subjected to T 2 and lower (2.0 ± 0.1) for the fish reared under T 3 . The highest condition factor (K) (2.54 ± 0.0) was observed for the fish reared in ponds under T 1 whereas fish under T 2 had the lowest value (2.05 ± 0.0). It is concluded that, the combination of pond fertilization plus concentrate feeding (T 3 ) is the best strategy for rearing Oreochromis niloticus, since it reduces feed utilization and results into higher growth performance and profit.
Evaluation of biofilter performance with alternative local biomedia in pilot scale recirculating aquaculture systems
(Elsevier, 2022) Munubi, Renalda N; Pedersen, Lars-Flemming; Chenyambuga, Sebastian W; Mnyoro, Samwel Mang’era
Plastic is commonly used as biofilter media in recirculating aquaculture systems. Because plastic is relatively expensive and may erode and emit microplastics to the environment, efforts are being made to test and develop more sustainable materials. Five alternative locally available biofilter media were compared with commercial plastic media and evaluated in duplicate in 1 m 3 two pilot scale Recirculation aquaculture system. Ammonium chloride and sodium nitrite were added to the systems for 4 weeks followed by stocking 20 kg of Nile tilapia in each system. Volumetric total ammonia nitrogen (TAN), nitrite and oxygen conversion rates were assessed for ten weeks. All biofilters with local media matured and reached full capacity after six weeks, while commercial plastic biomedia matured after seven weeks. This study found that the performance of commercial plastic biomedia was similar to performance of coconut shells in terms of volumetric TAN conversion rate (VTR), volumetric nitrite conversion rate (VNR) and volumetric oxygen conversion rate (VOCR). The highest VTR recorded in this study was 599 ± 15.8 g TAN/m 3 /d from coconut shells while the lowest was 343 ± 8.9 g TAN/m 3 /d from cattle horns. Biofilters with commercial plastic media had the highest VNR (704 ± 50.3 g NO 2 –N/m 3 /d) while media made of cattle horns was the lowest (457 ± 46.1 g NO 2 –N/m 3 /d). Biofilters containing coconut shells demonstrated the highest oxygen consumption around 3.0 g/m 3 /d and biofilters containing charcoal consumed less than 1.0 g/m 3 / d of oxygen. This study suggests that coconut shells can be used in place of plastic materials in simple recir culation aquaculture system biofiltration. This study also recommends further studies on comparing coconut shells with other biomedia and assessing its effects on water quality parameters and durability.
Influence of inorganic fertilizer application and supplementary feeds on periphyton biomass, quality and species composition
(International Journal of Fisheries and Aquatic Research, 2020) Shabani, Salimu; Munubi, Renalda N
A study was conducted to assess the effects of fertilization alone (T 1 ), supplementary feeding alone (T 2 ) and combination of fertilization plus supplementary feeding (T 3 ) on periphyton species composition, quantity and quality. Sex-reversed Oreochromis niloticus fingerlings were stocked in earthen ponds one week after initial pond fertilization. Urea and Diammonium phosphate (DAP) fertilizers were applied in pond water at weekly intervals at a rate of 3 and 2 g/m 2 , respectively. Fish were fed feed containing 25.1% crude protein at 5% (T 2 ) and 2.5% (T 3 ) of fish body weight daily. The results show that the ponds under combination of fertilization plus supplementary feeding (T 3 ) had higher periphyton biomass (47.35 ± 7.64 g DM/m 2 ), crude protein content (11.40 ± 0.16%) and organic matter content (OM) (25.47 ± 0.28%). The periphyton from ponds under fertilization alone (T 1 ), had the highest ether extract content (1.84 ± 0.07%) and ponds treated with supplementary feeding alone (T 2 ) had higher phosphorous content (0.48 ± 0.0 mg/L). The body of fish cultured in ponds under T 3 had higher CP (69.14 ± 0.33%) and OM (96.65 ± 0.16%) contents while those reared under T 1 had higher ether extract content (18.33 ± 0.19%) and ash content (4.78 ± 0.1%), suggesting a positive relationship between algal quality and fish muscles. In addition, fish growth rate increased as the periphyton quantity (biomass and OM) and quality (CP and phosphorous) increased. The study also revealed five classes of phytoplankton (Bacillariophyceae, Chlorophyceae, Cyanophyceae, Euglenophyceae and Zygnematophyceae) and three classes of zooplankton (Eurotatoria, Heterotrichea and Oligohymenophorea). In general, both phytoplankton (algae) and zooplankton were more abundant in ponds under T 3 than in ponds under the other treatments. It is concluded that the combination of fertilization plus supplementary feeding (T 3 ) produces higher periphyton quantity, quality and species composition and thus promotes higher fish growth rate compared to feeding alone and fertilization alone treatments.