Rivers State University of Science and Technology

About: Rivers State University of Science and Technology is a education organization based out in Port Harcourt, Rivers, Nigeria. It is known for research contribution in the topics: Population & Threatened species. The organization has 1826 authors who have published 1833 publications receiving 15183 citations.

Foraging mode, relative prey size and diet breadth: A phylogenetically explicit analysis of snake feeding ecology

Abstract: Foraging modes (ambush vs. active foraging) are often correlated with a suite of morphological, physiological, behavioural and ecological traits known as the "adaptive syndrome" or "syndrome hypothesis." In snakes, an ecological correlate often reported in the literature is that ambush-hunting snakes have a higher relative meal size compared to actively foraging snakes which feed on smaller prey items. This "large meal versus small meal" feeding hypothesis between ambush and active foragers has become a widely accepted paradigm of snake feeding ecology, despite the fact that no rigorous meta-analysis has been conducted to support this generalization. We conducted a phylogenetically explicit meta-analysis, which included ca. 100 species, to test this paradigm of snake feeding ecology. We gathered data on prey size by inducing regurgitation by palpation in free-ranging snakes and by examining the stomach contents of preserved museum specimens. When we found prey, we recorded both snake and prey mass to estimate relative prey mass (prey mass/snake mass). We also reviewed published studies of snake feeding ecology to gather similar information for other species. Ambush and active foragers did not differ in minimum or average meal size but the maximum meal sizes consumed by ambush-foraging snakes were larger than the maximum meal sizes eaten by active foragers. This results in ambush-foraging snakes consuming a significantly wider range of meal sizes, rather than being large meal specialists compared to active foragers. We argue that ambush foragers evolved to be more opportunistic predators because they encounter prey less frequently compared to active foragers. This hypothesis is further supported by the fact that ambush foragers also exhibited marginally wider diet breadths, consuming a broader range of prey types in comparison with active foragers. Our study challenges aspects of the foraging syndrome as it is currently conceived, and our results have important implications for our understanding of how foraging mode has shaped the behaviour and physiology of ambush-foraging snakes.

Size-relative Effectiveness of Clove Oil as an Anaesthetic for Rainbow Trout (Oncorhynchus mykiss Walbaum, 1792) and Goldfish (Carassius auratus Linnaeus, 1758)

Abstract: The purpose of this work was to investigate the size-relative effectiveness of clove oil as an anaesthetic for rainbow trout and goldfish. In total, 128 rainbow trout (Oncorhynchus mykiss) (two groups of 20-23 and 30-33 cm mean fork length) and 160 goldfish (Carassius auratus) (four size groups of 1.5-2.5, 5-7, 11-15 and 20-25 cm) were anaesthetized at different clove oil concentrations of 50, 100, 150 mg·l -1 for trouts and 75, 100, 150 mg·l -1 for goldfish. Rainbow trout exhibited total loss of balance and no response to external stimuli with shorter induction time as dosage increased (120.5 s, 64.4 s and 44.3 s, respectively). Goldfish exhibited total loss of balance and no response to external stimuli after induction time that varied with dosage used and body size of fish. The small fish (1.5-7 cm) exhibited shorter induction time which ranged from 84.28 s at 75 mg·l-1 clove oil to 41.14 s at 150 mg·l-1 clove oil. The larger fish had a longer induction time inversely related to the dosage. Recovery time was longer than induction time in both species. Both species recovered within 6 min after anaesthesia at 150 mg·l-1 clove oil. Clove oil did not produce marked changes (P 0.05). For both fish species, clove oil was effective, producing minimum stress and zero mortalities, and can be recommended as an effective anaesthetic. Syzygium aromaticum, fish anaesthesia, animal welfare Rapid expansion of the aquaculture industry that occurred in previous decades prompted scientific debates on the potential suffering of fish being handled during common aquaculture procedures or during slaughtering. Research aimed at lessening the suffering of cultured fish is vital to meet the concern for farmed fish welfare (Ashley 2007). Handling stress and various manipulations in aquaculture can have a negative impact on fish health and their growth (Hoskonen and Pirhonen 2006). Anaesthetics are therefore applied to reduce these negative effects to the minimum. The dosage required to induce general anaesthesia varies according to the anaesthetic used and other factors such as water temperature, hardness, salinity, oxygen concentration, length of exposure, body weight, the ratio of gill area/body surface area and the species of fish. In general, small fish are more sensitive to anaesthesia than larger fish (Ross and Ross 1999). An ideal anaesthetic for fish should induce anaesthesia in less than 3 to 5 min, with total loss of balance and muscle tone, allowing an uneventful and rapid (i.e. less than 10 min) recovery with low tissue residues after recovery, thus being safe to users and consumers. The anaesthetic should be inexpensive and easy to use (Gilderhus and Marking 1987;

HIV Infection in Long-Distance Truck Drivers in a Low Income Setting in the Niger Delta of Nigeria

Abstract: The aim of this study was to determine the seroprevalence, and correlates of HIV infection among long-distance truck drivers in Port Harcourt, Nigeria. A total of one hundred (100) long-distance truck drivers aged between 21 and 60 years and mean age of 42.36 ± 5.23 years were screened for the presence of HIV antibodies. The results showed that, out of the total number screened 10 (10%) were positive for HIV while 90 (90%) were negative. The prevalence of HIV was significantly higher in the 31–40 years age group 6/26 (23%) compared to 1/13 (7.6%) in the 21–30 years age group and 2/37 (7.4%) in the 51–60 years age group (P = 0.04).The lowest prevalence of HIV occurred in the 41–50 years age group 1/24 (4.2%). HIV 1 was the predominant viral subtype among the subjects 9 (90%) while 1 (10%) had HIV-2. None of the HIV-positive subjects had dual HIV 1 and 2 infections. The mean CD4 lymphocyte count for subjects positive for HIV was 380 ± 68.0 (range 312–448 cells/μl) while CD4 count for HIV negative subjects was 780 ± 76 cells/μl (range 704–856 cells/μl. A significant negative correlation was observed between HIV positivity and CD4 count r = −0.010 (P = 0.01). It is recommended that intensive preventive measures be instituted coupled with the implementation of a vigorous enlightenment campaign targeting behavioral change from high risk culture among truckers. Efforts are urgently needed to provide access to sexual health education, treatment services and HIV testing facilities to reduce their vulnerability to HIV infection.