https://commons.ru.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://commons.ru.ac.za/vital/access/manager/Repository/vital:3300 Wed 22 Jun 2022 12:59:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2638 Wed 20 Jul 2022 12:21:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:989 Wed 07 Jul 2021 12:03:52 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:7203 Tue 24 Aug 2021 16:22:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1432 Tue 10 Aug 2021 12:38:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5483 Thu 26 Aug 2021 14:37:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:734 Thu 13 May 2021 15:32:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3927 3 h), depolymerizing the pectin backbone while releasing the inulins from within the chicory roots. Analysis of various mixtures of FOS by mass spectrometry, HPLC and ¹H-NMR was undertaken. Results indicated that MS with electrospray ionization and ¹H-NMR are capable of providing relative quantitative data of the FOS present in the mixtures. The pharmaceutical effects of various sc-FOS (0.5%, v/v) and SCFA (0.3%, v/v) on certain bacterial enzymes (β-glucuronidase, urease and β-glucosidase) associated with the formation of carcinogens were also studied. These enzyme activities were not directly influenced by the sc-FOS, but were found to be remarkably decreased by SCFA, pointing toward the prebiotic effect of FOS in intestinal microflora modulation.]]> Thu 13 May 2021 11:50:24 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3760 Thu 13 May 2021 09:28:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5460 Thu 13 May 2021 09:13:17 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4888 Thu 13 May 2021 08:24:02 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4594 Thu 13 May 2021 08:18:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:795 Thu 13 May 2021 08:18:04 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:987 Thu 13 May 2021 08:11:35 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1954 Thu 13 May 2021 08:09:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1652 Thu 13 May 2021 08:04:16 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4368 Thu 13 May 2021 07:39:04 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2102 Thu 13 May 2021 07:30:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4757 Thu 13 May 2021 07:21:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2832 Thu 13 May 2021 07:15:47 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4305 Thu 13 May 2021 07:09:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1647 Thu 13 May 2021 07:06:48 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5576 Thu 13 May 2021 06:55:34 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3721 Thu 13 May 2021 06:49:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5406 Thu 13 May 2021 06:49:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3088 Thu 13 May 2021 06:48:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5352 20°C). The aim of the study was to develop size and temperature specific diets for H midoe through optimisation of dietary protein, energy and lipid levels. Abalone were cultured under farm-like conditions in three partially recirculating temperature controlled systems at either 18, 22 or 24°C and fed formulated diets containing graded levels of protein (18,22 and 26 %) and energy (11.6, 13.5 and 16.2 MJ.kg·I ). Abalone were stocked into baskets at 5 % of available of surface area (n=36) and each diet (n=9) was fed to four baskets of abalone at each of the three temperature regimes for ten weeks. Abalone growth was temperature dependent, with growth declining from 4.33 g.month-I for abalone cultured at 18°C to 0.77 g.month-I at 24°C. Dietary protein could be reduced from 26 to 18 % provided dietary energy levels were maintained at 13.5 MJ.kg- l • A dietary energy level of 11.6 MJ.kg-1 was insufficient to meet the energetic requirements of H midae regardless of the protein content of the diet. The effects of water temperature and body size on the protein requirements of H midae were investigated by culturing abalone at temperatures within the optimal range for abalone farming (i.e. 14, 16 and 18°C). Three size classes of abalone (15, 50 and 80 mm) were fed formulated feed containing graded levels of dietary protein (20, 26, 32, 38 and 44 %) under controlled laboratory conditions for 12 weeks, and, in a separate experiment, under commercial farm conditions for 24 weeks. It was not possible to convincingly define the optimal protein levels for abalone of different sizes in this experiment because growth rates fell below average commercial growth rates obtained on farms. Growth was temperature dependent in the laboratory trial, with the rate of weight gain of the 15 mm (ANOV A: p=0.002) and 50 mm abalone (ANOV A: p=0.02) increasing significantly with an increase in temperature from 14 to 18°C. In the farm trial, dietary protein content did not affect the growth rate of the 10-15 or 80 mm abalone (ANOVA: p>0.05), however, the 50 mm abalone displayed significantly higher weight gain on the 32 % (4.72±0.20 g.month-I ) and 38 % (5.01±0.34 g.month-I ) protein diets compared to those fed the 20 % protein diet (3.75±0.13 g.month-I ) (ANOVA: p=O.OI). Although definition of optimal dietary protein levels were not possible, the effects of dietary protein content and water temperature on the growth of H midae were independent signifying that the protein requirements of abalone are temperature independent. In addition, there was no evidence to indicate that abalone of the different sizes tested here had different dietary protein requirements. The size specific dietary lipid and protein requirements of H midae were investigated by feeding two size classes of abalone (30 and 60 mm initial shell length) diets containing graded levels of dietary lipid (4, 7, 10, 13 and 16 %) and protein (34 - 39 %) for 12 weeks. The 30 and 60 mm abalone were stocked at 7 (n=200) and 9 % (n=36) of the available basket surface area respectively and each diet was fed to four baskets of abalone of each size class. The protein requirements of H. midae are influenced by the amount of available dietary energy and thus it is possible that the ability of abalone to utilise lipids as a source of energy differs in the presence of varying levels of dietary protein. High levels of dietary lipid negatively affected the growth, condition factor and soft tissue glycogen content of both size classes of abalone. This negative effect was greater in the 30 mm size class compared to the 60 mm abalone. The corresponding increase in feed consumption and feed conversion ratio in response to increasing levels of dietary protein also provides evidence that abalone are unable to utilise dietary lipids as an energy source and high levels of dietary lipid probably inhibit the uptake of carbohydrates and protein. High dietary lipid levels did however appear to promote gonad maturation. It was possible to reduce dietary protein from 34 to 20 % without negatively affecting growth through the maintenance of dietary energy levels and thus it is recommended that future experiments on the energy content of formulated feeds should focus on the improved use of carbohydrates. Reductions in the protein portion of formulated feeds for H. midae are possible provided the diet contains sufficient levels of energy supplied from carbohydrates. As the ability of abalone to utilise dietary lipid is limited, lipids are unlikely to play a significant role as an energy source in abalone feeds. Further investigations should focus on the utilisation of various carbohydrate sources in abalone feeds.]]> Thu 13 May 2021 06:48:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:944 Thu 13 May 2021 06:43:34 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1567 Thu 13 May 2021 06:41:30 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1642 Thu 13 May 2021 06:39:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1558 Thu 13 May 2021 06:29:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5295 1.0 dpm.g⁻¹). An analysis revealed ontogenetic differences in radium-226 uptake that may be attributed to changes in habitat or diet. Radiometric age from otolith core studies was used to describe a radium-226 uptake time-series for some species, which revealed interesting patterns over long periods. This synopsis provides information on the uptake of radium-226 to otoliths from an environmental perspective, which can be used as a basis for future studies.]]> Thu 13 May 2021 06:26:57 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4360 Thu 13 May 2021 06:16:05 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3938 Thu 13 May 2021 06:15:11 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3965 1 mM resulted in the precipitation of protein-nanoparticle bioconjugates, due to unfavourable acidic conditions. This demonstrated that the nanoparticles were binding to and becoming stabilised by general protein in the cell-free solution. Upon addition of a sodium-bicarbonate buffer, a general increase in Pt(IV) reduction to Pt(II) was observed. The addition of the buffer also resulted in an unexplained change in particle morphology and for this reason was not used in subsequent investigations. Polyvinylpyrrolidone (PVP) was shown to compromise the reduction rate of the Pt(IV) ion by SRB cells. The presence of extracellular NP’s was suggested by the colour of the supernatant turning brown and the A334 increasing over time. Attempts to visualise the particles by transmission electron microscopy (TEM) resulted in an unexpected phenomenon where nanoparticles could be observed to form dynamically upon irradiation by the electron beam. Extended irradiation by the electron beam also resulted in structural changes of the particles occurring during observation. An increase in temperature was shown to increase the reduction rate which in turn resulted in particles decreasing in size. The starting pH was shown to have a significant effect on the reduction rate and particle morphology although specific trends could not be identified. In conclusion, the cell-soluble extract from the sulfate-reducing consortium investigated, is capable of Pt(0) nanoparticle synthesis. Precise control over the particle morphology was not attained although the mechanism was further clarified and optimal conditions for nanoparticle synthesis were determined.]]> Thu 13 May 2021 06:12:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1768 Thu 13 May 2021 06:06:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3622 Thu 13 May 2021 06:02:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2417 Thu 13 May 2021 06:01:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:792 Thu 13 May 2021 05:58:26 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2840 Thu 13 May 2021 05:54:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1550 Thu 13 May 2021 05:45:02 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:757 Thu 13 May 2021 05:44:42 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1677 Thu 13 May 2021 05:41:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4838 Thu 13 May 2021 05:38:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2829 Thu 13 May 2021 05:33:08 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6619 Thu 13 May 2021 05:30:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5299 Thu 13 May 2021 05:26:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5110 Thu 13 May 2021 05:20:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5113 Thu 13 May 2021 05:16:26 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3691 Thu 13 May 2021 05:15:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5247 Thu 13 May 2021 05:14:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3686 Thu 13 May 2021 05:11:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1885 Thu 13 May 2021 05:08:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3717 Thu 13 May 2021 05:06:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:729 Thu 13 May 2021 05:03:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3928 Thu 13 May 2021 05:03:04 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:947 Thu 13 May 2021 04:59:13 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1817 Thu 13 May 2021 04:57:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3457 Thu 13 May 2021 04:49:50 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4211 Thu 13 May 2021 04:48:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:32275 Thu 13 May 2021 04:48:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4370 Thu 13 May 2021 04:48:05 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4836 Thu 13 May 2021 04:39:58 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3583 Thu 13 May 2021 04:36:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2399 Thu 13 May 2021 04:32:47 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1509 Thu 13 May 2021 04:31:53 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2849 Thu 13 May 2021 04:29:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2549 Thu 13 May 2021 04:26:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2778 Thu 13 May 2021 04:24:09 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4329 Thu 13 May 2021 04:20:12 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1464 Thu 13 May 2021 03:59:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3086 Thu 13 May 2021 03:57:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2194 Thu 13 May 2021 03:54:47 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:735 Thu 13 May 2021 03:53:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3993 Thu 13 May 2021 03:50:16 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:983 Thu 13 May 2021 03:45:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4764 Thu 13 May 2021 03:43:02 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3184 Thu 13 May 2021 03:40:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30662 Thu 13 May 2021 03:37:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5791 0.05). Total integrated mesozooplankton abundance and biomass during the study ranged between 3934.9 and 308521.4 ind.m-2 (mean = 47198.19; SD±62411.4 ind.m-2) and between 239.8 and 4614.3 mg Dwt.m-2 (mean = 1338.58; SD ±1060.5), respectively. Again, there were no significant spatial patterns in the total mesozooplankton abundance or biomass within the region of study (p>0.05). No significant correlations were found between biological (chlorophyll-a concentrations and zooplankton abundance) and physico-chemical variables (temperature and salinity) (p>0.05). The total mesozooplankton community was numerically dominated by copepods of the genera Pleuromamma, Calanus, Oncaea and Oithona. Other important representatives of the mesozooplankton community included the tunicate, Salpa thompsoni, and the pteropod, Limacina retroversa. At the 40% similarity level, numerical analysis identified five distinct mesozooplankton groupings within the survey area. Differences between the groupings were associated with changes in the relative contribution of numerically dominant species rather than the presence or absence of individual species. No groupings were associated with any specific feature of the front within the survey area. The feeding rates of the six most numerically abundant mesozooplankton species (Calanus simillimus, Limacina retroversa, Pleuromamma abdominalis, Clausocalanus breviceps, Oncaea conifera, Salpa thompsoni) accounting for on average 39% of the total mesozooplankton counts, were investigated using the gut fluorescence technique. For all species, the total gut pigment contents during the night time were significantly higher than the daytime values (p<0.05 for all species). The gut evacuation rates (k) for selected mesozooplankton ranged between 0.14 and 0.81 h-1. The ingestion rates ranged between 147.8 and 5495.4 ng(pigm)ind-1.day-1 which corresponded to a daily ration of between 2.4 and 10.9% body carbon. The combined grazing impact of the selected species on the daily phytoplankton standing stock was highly variable and ranged between 1.2 and 174.1% with an average of 27.3% (SD±38.78%) within the survey area. The highest grazing impact (>60%) was typically associated with those stations where the pteropod, L. retroversa, and the tunicate, S. thompsoni, contributed more than 5% of the total mesozooplankton counts. No significant differences were found in the grazing impact of any or all selected species situated either north, south or in the immediate vicinity of the front (p>0.05 in all cases). The lack of defined spatial patterns in the mesozooplankton abundance and community structure suggests that the STC did not act as a significant biogeographic barrier to the distribution of mesozooplankton during the study. It is presumed that the large scale mixing event caused by a storm prior to this study was responsible for the observed lack of elevated biological activity within the region of the STC.]]> Thu 13 May 2021 03:30:47 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2708 Thu 13 May 2021 03:30:10 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1858 Thu 13 May 2021 03:25:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1702 Thu 13 May 2021 03:21:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1149 Thu 13 May 2021 03:20:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5566 Thu 13 May 2021 03:16:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3426 Thu 13 May 2021 03:08:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:959 Thu 13 May 2021 02:44:10 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4401 Thu 13 May 2021 02:42:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2202 Thu 13 Jan 2022 11:28:09 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1999 Thu 13 Jan 2022 11:22:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6618 Thu 07 Jul 2022 20:39:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6614 Thu 07 Jul 2022 20:39:10 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6616 Thu 07 Jul 2022 20:38:47 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6615 Thu 07 Jul 2022 20:38:26 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:7200 Thu 07 Jul 2022 16:08:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2944 Mon 15 Aug 2022 13:29:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6617 Mon 05 Jul 2021 15:47:34 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2648 Mon 04 Dec 2023 09:03:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:587 Fri 26 Apr 2024 11:28:03 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3978 Fri 06 Aug 2021 11:41:17 SAST ]]>