Olufemi Owolabi
@unilorin.edu.ng
Associate Professor, Faculty of Life Sciences
University of Ilorin
RESEARCH, TEACHING, or OTHER INTERESTS
Animal Science and Zoology, Aquatic Science
Scopus Publications
Scopus Publications
Bernard Edah and Olufemi David Owolabi
Springer Science and Business Media LLC
AbstractA twin-screw hot extrusion processing study was performed using defatted black soldier fly larvae (DBSFL) meal as a complete substitute for Danish fishmeal (DFM) in the production of aqua-feed. The defatting process of full-fat black soldier fly larvae (BSFL) reduced its crude fat content by 60%. This was mixed together with other ingredients (soybean meal, cassava flour, vitamin and mineral mix, vitamin C, and anti-mold) to formulate a fish diet containing 40% crude protein. The moisture content of the formulated mixture was 300 g/kg prior to extrusion. The extruder feeder motor speed, main motor speed and cutter motor speed were set at 210, 300 and 700 rpm respectively. Results show a significant increase (P < 0.05) in the crude protein (CP) content of DBSFL meal when compared with full-fat BSFL meal with values of 51.83 ± 0.03 and 47.44 ± 0.2 respectively. However, CP values of the DBSFL meal were significantly (P < 0.05) lower than those obtained for DFM with values of 51.83 ± 0.03 and 72.13 ± 0.18 respectively. The physical properties of extruded floating pellets showed significant differences (P < 0.05) between DFM-based extrudates and DBSFL-based extrudates in terms of expansion ratio (ER), sinking velocity (SV), Unit density (UD), bulk density (BD), and pellet durability. However, no significant differences (P > 0.05) were observed in terms of floatability, moisture content and water absorption index (WAI). It was concluded that, the extrusion of DBSFL-based pellets compared favourably with DFM-based extruded pellets thus, the processing of full-fat BSFL into DBSFL meal makes the latter suitable for extrusion purposes and appropriate in the production of good quality floating feed pellets desired by fish farmers and suitable for feeding fish.
Olagbemide P. T. and Owolabi O. D.
Journal of Experimental Biology and Agricultural Sciences
In Ekiti State, southwest Nigeria, Oreochromis niloticus is significant to live. This investigation was conducted to improve its sustainable management and access the length-weight relationship and condition factor of O. niloticus across important reservoirs in Ekiti State from November 2017 to October 2019. Collected specimens were weighed to the nearest gram, while the entire lengths were measured to the closest centimetre. Log-transformed regression was used to determine the fish's growth pattern in the reservoirs. The gradient comparison was done using the T-test. The length and weight of the species in the reservoirs showed a significant association. All length-weight relationships had r2 values greater than 0.8150 and were significant at P < 0.05. In the length-weight relationship of O. niloticus, the values of the exponent b in Egbe, Ero, and Ureje reservoirs varied from 2.45 to 2.87, 3.02 to 3.20, and 2.45 to 2.82, respectively. The results of regression coefficient b obtained showed that in the combined season, male, female and combined sexes from the Ero reservoir had isometric growth patterns with growth exponent b values of 3.18, 3.20 and 3.19 respectively that were not statistically different from 3. These results contradicted the negative allometric growth pattern in the Egbe and Ureje reservoirs. The condition factor during the dry season ranged from 1.93-2.05, 2.05-2.11, and 1.93-2.03 for fish in Egbe, Ero, and Ureje reservoirs, respectively while in the rainy season, it ranged from 2.00-2.02; 2.08-2.09 and 1.96-2.01 respectively. The fish species studied in the reservoirs lived above- average life and thus indicate that the prevailing ecological conditions in the reservoirs were not beyond the forbearance range for the fish species since their condition factors were within the range considered adequate for freshwater fishes in tropical waters.
Olagbemide P. T. and Owolabi O. D.
Journal of Experimental Biology and Agricultural Sciences
Water is indispensable to life. Consequently, water and sediment contamination poses severe ecological threats to life. Thus, this investigation aimed to evaluate metal deposition in the sediments and surface water in Ekiti State's three dams and to analyze its potential ecological effects on man's bodily, social, and mental well-being. Metal levels in sediments and dam water were determined using Atomic Absorption Spectroscopy (AAS). Average values of the metals in Egbe, Ero, and Ureje dams, except for K, Mn, and Pb (in Ureje dam), were lower than the acceptable boundaries of local and foreign establishments. The values of the risk quotient (HQ) on the skin and consumption contacts with all metals (except Mn for ingestion exposure for children) were less than one in the Egbe, Ero, and Ureje dams for both adults and children. Consumption HQ values were higher than skin HQ values in the three dams for children and grown-ups. The total hazard index (HI) posed adverse non-carcinogenic risk to children in the catchment area of the dams while the adults were not affected by the non-carcinogenic hazard. The highest cancer hazard was found in the Ureje dam, while the lowest was in the Ero dam. Further, adults were prone to higher cancer risk than children. Using multiple pollution indices revealed that the sediments in Egbe, Ero, and Ureje dams were less contaminated by harmful metals in dry and wet periods. There is a need to reduce current polluting anthropogenic activities around the dams.
Olufemi D. Owolabi and Saratu I. Abdulkareem
Egypts Presidential Specialized Council for Education and Scientific Research
Degradation of aquatic environment due to chemical pollution can be implicated for fish production decline in developing countries, particularly Nigeria. Among the emerging chemical pollutants with the potential of decimating the aquatic ecosystems are the nanoparticles. Nonetheless, owing to the exceptional characteristics of negligible size, reaction activity, and extensive surface area nanoparticles have clearly shown potential beneficial use in the manufacture of consumer and industrial products. Zinc oxide nanoparticles (ZnO-NPs) are among the commonly utilised nanoparticles by most industries in the production of commercial and medicinal goods as a result of their distinguished physicochemical properties such as rigidity, photo stability, and biodegradability. Thus, ARTICLE INFO ABSTRACT Article History: Received: March 9, 2021 Accepted: July 20, 2021 Online: Sept. 7, 2021 _______________
OD Owolabi and MK Babarinsa
IOP Publishing
Abstract A 63-day experiment was conducted to determine the effects of nanoselenium formulated diets on growth performance, nutrient utilization and haematological profile of Clarias gariepinus. Fish were acclimatized for 14 days, 10 fish each were randomly introduced into different troughs. Feed supplemented with nanoselenium at 2 mg/kg, 4 mg/kg and the control without nanoselenium were fed to group of fish each in triplicate. The feed intake, weight gain, food conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER) and survival rate (SR) were determined, also the haematological profile of Clarias gariepinus fed were analyzed. There were significant increase (p<0.05) in the weight gain of fish fed 2 mg/kg of nanoselenium as compared with those fed 4 mg/kg of nanoselenium and the control. Similarly, PER and SR were significantly higher (p<0.05) in 2 mg/kg when compared with other formulated diets. The FCR of fish fed 2 mg/kg was significantly lower compared with 4 mg/kg nanoselenium formulated diets. WBC, RBC, haemoglobin, and haematocrit significantly increased in fish fed 2 mg/kg of nanoselenium as compared with those fed 4 mg/kg nanoselenium and the control group while there was variation in the values of other haematological parameters such as platelets, MCV, MCH and MPV. The research indicated that dietary inclusion of nanoselenium at 2 mg/kg may enhance better growth performance and nutrient utilization of Clarias gariepinus.
Olufemi D. Owolabi
Springer Science and Business Media LLC
Olufemi D. Owolabi
Science Alert
Olufemi D. Owolabi .
Science Alert
The influence of size, sex and season on the feeding regime of S. membranaceus were examined over a period of 24 months in Jebba Lake, Nigeria using frequency of occurrence, numerical, gravimetric and index of Relative Importance (RI) methods. Dietary composition and feeding intensity were sex dependent. RI established that there was a progression from a detritivorous diet in fish below 20 cm Standard Length (SL), through a transitional planktivorous phase (20-27 cm, SL), to a predominantly molluscivorous/insectivorous diet in fish above 27 cm SL; thus indicating a switch from a relatively passive filter-feeding habit when young to an active predatory habit at adult stage. Food preference also varied with season hence intraspecific competitions were low. Abundant food and ability to evolve trophic strategies that ensure optimum foraging in spite of seasonal changes enable S. membranaceus to maintain its overwhelming prominence and wide distribution in Jebba Lake.