Effect of dietary protein regime during the growing period on growth performance, feed utilization and whole-body chemical composition of Nile Tilapia, Oreochromis niloticus (L.)

This study was conducted to evaluate the effect of various dietary protein regimes on growth performance, feed utilization and whole-body chemical composition of Nile tilapia, Oreochromis niloticus (L.). Twenty cages (1 m³ each) were randomly allocated to a four-replicate experiment to represent five treatments (T1–T5) where fish were randomly stocked at a rate of 50 fish (1.5–2.2 g) per cage. Fish in T1–T5 fed on a 45% crude protein (CP) diet for the first 4 weeks. In T1, T2 or T3 fish fed on 45%, 35% or 25% CP diets for the last 8 weeks respectively. In T4 fish fed 35% CP diet for the second 4 weeks followed by 25% CP diet for the last 4 weeks and in T5 fish fed 25% CP diet for the second 4 weeks followed by 35% CP diet for the last 4 weeks. Diets were offered to satiation and provided manually twice a day in the morning and in the afternoon, 6 days a week. The optimum fish growth and feed utilization were obtained at T1, T2 and T4. Protein efficient ratio and apparent protein utilization were lower at T1 and T2 than those of T3–T5. On the other hand, no significant changes in energy utilization were observed among the different treatments. There were no major changes in the carcass composition except in ash content, which was higher in T3 and T5 only. This study recommended that the dietary protein regime is an important management in tilapia culture, and the protein level could be reduced from 45% to 35% then to 25% on increasing the fish size.     

Capability of some agricultural wastes for removing some heavy metals from polluted water stocked in combination with Nile tilapia,Oreochromis niloticus (L.)

Heavy metal (HM) pollution is one of the major problems that adversely affect the aquatic ecosystem and inhabiting biota. Heavy metals adsorption by low-cost adsorbents is one of the techniques used for HM removing from polluted water. In the present study, agricultural wastes (AW), i.e., rice straw, sugarcane bagasse, and maize stalks, were washed with distilled water, dried in a dry-oven, cut into small pieces (<0.5 cm long), and immersed at 1.0 g/L in aquaria containing synthetic mixture of lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn). Nile tilapia, Oreochromis niloticus (L.), fingerlings (25.2 ± 0.88 g) were stocked at a density of ten fish per 100-L aquarium for 72 h, during which fish were fed on a fish diet containing 25% crude protein ad libitum twice daily. Samples of water, AW, and fish were collected at different times to determine HM concentrations. The HM removal from polluted water was depending on the type of the metal ions, AW, and the contact time. However, HM concentrations in aquaria waters of all AW treatments decreased significantly by increasing contact time up to 24 h after which their concentrations were almost the same. Concentrations of waterborne Pb, Cd, Cu, and Zn in AW-containing aquaria were significantly lower than those of AW-free aquaria. The presence of any AW reduced significantly HM concentrations. In AW-free aquaria, HM-exposed fish accumulated more HM in their body than those reared in AW-containing aquaria. The results of this experiment showed that all AW had the capability to remove HM levels from the polluted water and reduce their bioaccumulation in fish body. However, rice straw was the more efficient adsorbent for all metals.     

Improving productivity of steviol glycosides in Stevia rebaudiana via induced polyploidy

Journal of Crop Science and Biotechnology - The polyploidy induction using mutagenic chemicals is one of the breeding approaches to improve enhancing productivity of yield and secondary metabolites...     

Plant community dynamics in arid lands: the role of desert ants

Ants (Formicidae, Hymenoptera) play an important role in seed bank, seedling establishment andplant composition of arid ecosystems. Thus, knowing plant-ant interaction provides useful information formanagers to design restoration and conservation plans. In this study, the roles of desert harvester ants (Messorintermedius and Messor melancholicus) and scavenger ants (Cataglyphis nodus and Lepisiota semenovi) on plantcommunities were investigated in arid ecosystems of southeastern Iran. Two vegetation types weredistinguished in the study area and the nest density of ant species was determined. Furthermore, plantcomposition and soil seed bank were estimated at different distances from the ant nests. Results showed thatthe density of M. intermedius and M. melancholicus nests was higher in dwarf shrub-shrub vegetation type and thedensity of C. nodus and L. semenovi nests was higher in dwarf shrub vegetation type. The harvester and scavengerants had enhanced the seed bank to 55% and 70%, respectively. Therefore, the role of scavenger ants on theplant communities' seed bank was greater than that of harvester ants. Although the scavenger ants were moreinfluential on the annuals and the invasive plant species, the radius impact of the harvester ants on theperennials was greater, i.e., a positive interaction existed between the perennial plants and the harvester ants. C.nodus and L. semenovi played an important role in enhancing the ecosystem's potential for restoration throughestablishment of pioneer species in early stage of succession. The activity of M. intermedius is crucial for thedevelopment and maintenance of climax plant communities in arid ecosystems through assisting the plantspecies' establishment in late stage of succession. It is essential to preserve the diversity of these key ant speciesfor the maintenance and sustainability of shrubs in arid ecosystems.     

Evaluation of gallbladder volume and contraction index with three-dimensional ultrasonography in healthy dogs

Three-dimensional (3D) ultrasonography has been shown to be an accurate and appropriate tool for measurement of gallbladder volume in humans. Therefore, we applied this novel technique for the first time to study fasting and postprandial gallbladder volume in 10 healthy dogs and compared the results with those of 2-dimensional (2D) ultrasonography. Fasting gallbladder volumes determined by 3D ultrasonography were significantly higher than corresponding volumes determined by 2D ultrasonography (P<0.01). Additionally, gallbladder volumes were significantly decreased in the postprandial state compared with the fasting state using 3D ultrasonography (P<0.001), but 2D ultrasonography showed no significant difference (P=0.189). The Gallbladder contraction index was higher in 3D ultrasonography than 2D ultrasonography; however, it did not reach statistical significance (P=0.25). In conclusion, 3D ultrasonography was able to measure gallbladder volume in healthy dogs in this study. It is suggested that 3D ultrasonography can be used to accurately estimate gallbladder volume and contractility.     

Die Einwirkung von Insektiziden auf die neurosekretorischen Zellen vonPemphigus bursarius L. (Aphidina)

Zusammenfassung Die histologischen Veränderungen nach der Anwendung der drei Insektizide, E 605, Systox und Plantaced, ergaben für die neurosekretorischen Zellen keine gleichartigen Veränderungen, vielmehr verhielten sich die verschiedenen Generationen in den untersuchten Entwicklungsphasen verschieden.Bei der Fundatrix traten eine Aufblähung des Plasmas und nekrotische Veränderung der Zellkörper sowie deutliche Volumenzunahme der Zellkerne bis zu ca. 78 ³ auf. Die NSZ zeigten abgeschwächte Färbbarkeit.Bei den geflügelten Nachkommen der Fundatrix wurden riesengroße NSZ beobachtet; das Volumen der Zellkerne war bis zu ca. 268 ³ gestiegen.Bei den Salatwurzelläusen konnten nach der Behandlung mit den genannten Insektiziden im Unterschlundganglion keine NSZ beobachtet werden. Eine starke Volumenabnahme der Zellkerne wurde, von ca. 268 ³ auf 50 ³ festgestellt. Nekrotische Veränderung der Zellkerne und Fragmentation (Karyorrhexis) des Chromatins waren nachweisbar. Der Unterschied im Verhalten der NSZ der Wurzelläuse im Vergleich zu den anderen Generationen ist vielleicht dadurch bedingt, daß die Wirkung der Insektizide im Boden anders ist.Bei den Sexuparae zeigte das Zellchromatin nach der Begiftung eine Pyknose, was schließlich zu einer Degeneration des Kernes führte. Außerdem trat eine Volumenzunahme des Nucleolus auf.Bei den Weibchen der zweigeschlechtlichen Generation war eine Veränderung der Kerne durch Schwellung zu beobachten, die mit großem Verlust der Färbbarkeit einherging.Bei den Männchen mit Flügelanlagen schließlich trat bei den Zellkernen der NSZ eine Volumenzunahme ein, jedoch zeigten die Nucleoli keine Vergrößerung. Am Zellchromatin war beginnende Pyknose zu bemerken. Beachtenswert war die wenig veränderte Gesamtanzahl der NSZ trotz Insektizideinwirkung. Die Prüfung mit dem t-Test ergab, daß die festgestellte Differenz zwischen den Mittelwerten normaler und behandelter Tiere nicht signifikant war.

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Summary Histological experiments have been performed on the neurosecretory system of various generations of the poplarlousePemphigus bursarius (L.), after injection of various phosphor-acid-ester insecticides (E 605, Systox and Plantaced), in sublethal doeses.After poisoning the nuclei of the neurosecretory cells of both the fundatrix and flying generations, became very distinct, increasing in volume until finally the chromophobic could be observed. On the contrary after poisoning the lettuce-root generation, the nuclei appeared to decrease in volume from the approximately 267 ³ down to 50 ³, and nekrosis was observed.The degree to which the different insecticides effected the nuclei of the Sexuparae generation has been examined and pyknosis has been observed, culminating in the degeneration of cell nucleus material.Progressive intoxication in females of the sexual generation caused the chromatine of the nuclei to lose its distinctive colouring, whilst in males similar intoxication caused the onset of pyknosis. In these circumstances it was not possible to observe any enlargement of nucleoli.In all generations the number of active neurosecretory cells in the different parts of the nervous system decreased after poisoning. No significant difference in the total number of neurosecretory cells present in the fundatrix generation and the males of the sexual generation was found.

     

Verhalten der Mycetomzellen nach Insectizid-Einwirkung beiPemphigus bursarius L. (Aphidina)

Zusammenfassung Das Mycetom der Pappel-BlattlausPemphigus bursarius L. wurde lichtmikroskopisch untersucht.Bei allen Generationen trat nach der Behandlung mit verschiedenen Phosphorsäureester-lnsectiziden (E 605, Systox, Plantaced) in sublethaler Dosis zunächst eine Auflockerung im Plasma der in den Mycetomzellen gelagerten Symbionten auf, später zeigte sich eine Auflösung der Zellwand der Mycetomzellen und eine dadurch bedingte Zerstreuung der Symbionten. Schließlich war bei den Nymphen und der geflügelten Generation Chromatolyse und Pyknose der Kerne der Mycetomzellen zu beobachten. Bei den Embryonen der verschiedenen lebendgebärenden Generationen konnte keine Gifteinwirkung bei den Mycetomzellen festgestellt werden. Das bedeutet, daß trotz starker Schädigung der Muttertiere, das Gift nicht bis zu den Embryonen vordringen konnte.Über die Durchlässigkeit der Uteruswandung konnten bislang noch keine Untersuchungen durchgeführt werden, so daß über die Ursachen der Unversehrtheit der Embryonen zunächst nichts ausgesagt werden kann.

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Summary The organe-coloured mycetom of the Poplar-lousePemphigus bursarius (L.) have been examined with a light microscope. By all generations of insects appear after injektion of various phosphor-acid-ester insecticide (E 605, Systox, Plantaced), in sublethal dose, a special loosening of plasma of the mycetom-cells, and later dissolving of mycetomal covering membranes, and finally dispersion of saccharomycetes of mycetomal cells. The effectiveness of insecticides in the nymph and flying insects generation has been expressed by cell-nucleus materials. I could not see any symptoms on mycetom cell of the embryos of various generations of insects. It is to indicate that, possibly no impairment of absorption or centripetal transport of insecticide has been forwarded to the embryos, accordingly the mechanisms of this very efficient absorption and centripetal transport in the insects-uterus has not yet been carefully studied.

     

Wirkungen von Precocen I aufCulex quinquefasciatus Say (Diptera,Culicidae)

Zusammenfassung Es wurden die Wirkungen von Precocen I (PI) unter Laborverhältnissen auf die frühen L4 und Puppen vonCulex quinquefasciatus bei Konzentrationen von 0,001–10,0 ppm untersucht. Das Spektrum der PI-Wirkungen schloß die Larven-und Adulten-Mortalität bei 0,1–10,0 ppm ein. Die Verpuppungs-und Adultenschlüpf-Periode wurden bei Dosen von 0,001–5,0 ppm verzögert. Auf die larvalen Nachkommen vonC. qu. wirkte sich die PI-Behandlung (0,001–10,0 ppm) in verringerter Fekundität und Eischlüpfquote, verzögerte Larvenentwicklung und schließlichem Absterben aus.

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Effects of precocene I onCulex quinquefasciatus Say (Diptera, Culicidae)

The effects of precocene-I (PI) onCulex quinquefasciatus Say were studied under laboratory conditions by treating laboratory reared early 4th instar larvae and pupae with 0.001–10.0 ppm of PI. The range of PI effects included larval and adult mortalities at 0.1–10.0 ppm. Pupation and adult emergence periods were delayed at 0.001–5.0 ppm. Effects of PI were maintained to offsprings ofC. quinquefasciatus. These effects involved reduced fecundity, reduced egg hatchability and delayed larval offspring development and finally the death at 0.001–10.0 ppm of PI.

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