Effects of dietary baker’s yeast extract on the growth, blood indices and histology of Nile tilapia ( Oreochromis niloticus L.) fingerlings

Nile tilapia, Oreochromis niloticus (average initial weight, 5.91 ± 0.04 g), were fed four isonitrogenous and isolipidic diets for 84 days. The diets contained four levels of yeast extract (CW‐I) rich in nucleotides and β‐glucan: 0 (control), 5, 10 and 15 g/kg diet. Weight gain increased linearly, whereas the feed conversion ratio decreased linearly with increasing levels of yeast extract. The diet containing 15 g/kg yeast extract resulted in significantly better (p 0.05) differences were found in dry matter, protein, lipid or ash contents or in haematocrit, haemoglobin or total protein contents among the treatment groups. Blood sample profiles showed an increase in white and red blood cells in fish fed 15 g/kg yeast extract in comparison with the other treatment groups. The fish fed the diets with 10 and 15 g/kg yeast extract had significantly higher albumin and globulin levels than the control group, whereas decreased levels of cholesterol and triglycerides, aspartate aminotransferase and alanine aminotransferase were noted in fish fed the diet with 15 g/kg yeast extract. Histological analysis of the liver and intestine in fish fed the control diet showed a slightly abnormal structure in these organs. Only in fish fed diets supplemented with the highest amount of yeast extract was the structure of the hepatocytes and villi almost unchanged, which indicated that the yeast nucleotides could improve hepatic function and promote liver and gut restoration

Appraisal of a high protein distiller’s dried grain (DDG) in diets for European sea bass, Dicentrarchus labrax fingerlings on growth performance, haematological status and related gut histology

High protein distiller's dried grains (HP‐DDG) are co‐products of ethanol production that uses prefractionation technology. An 8‐week growth trial was conducted to investigate the effect of partial replacement of soybean meal (SBM) by three levels of HP‐DDG (30%, 40% and 50%) on growth performance, physiological parameters and histological changes of the intestine of European sea bass, Dicentrarchus labrax. The results indicated that an increased dietary level of HP‐DDG of more than 30% significantly increases growth performance and improved the FCR of sea bass. In addition, replacement of SBM by HP‐DDG enhanced feed intake efficiency and the health status of fish. Haematology and serum biochemistry (haemoglobin (Hb), red blood cells (RBCs), white blood cells (WBCs), packed cell volume (PCV %) and humeral immune parameters including total protein, albumin, globulin, cholesterol, lysozyme activity and total antioxidant capacity significantly increased with increase HP‐DDG inclusion levels. The findings of this study indicated that HP‐DDG is a good complementary protein source for inclusion aquaculture diets and levels above 30% as a replacement of SBM did not compromise growth performance and physiological parameters of sea bass while enhancing some important indices of health status in this species

Построение математической модели ценообразования на телекоммуникационные услуги с учётом перегрузок в сетях

This paper considers a model of dynamic pricing in the telecommunications market incomplete competition and taking into account overloads in multiservice networks. The model consists in the use of mathematical modeling methods, game theory and queueing theory. It is assumed that telecommunication companies agree on the rules of incoming and outgoing traffic charging in pairs, and this charging is built as a function of the tariffs that companies offer their subscribers for service. Companies are limited the agreement on mutual rules of reciprocal proportional charging for access traffic at first, which subsequently determine the tariffs for the multiservice network users. The reciprocity of the rules means that companies are subject to the same rules for the entire time interval during which the agreement is in force. Taking into account imperfect competition in the telecommunications market and using profit optimization method for each company the equilibrium tariffs and the volume of services are found with subject to congestion in multi-service networks.В работе строится модель динамического ценообразования на рынке телекоммуникаций при условии ограниченной конкуренции и с учётом перегрузок в мультисервисных сетях. Для построения и исследования модели был применён комплексный подход, заключающийся в использовании методов экономико-математического моделирования и теории массового обслуживания. В предлагаемой модели предполагается, что телекоммуникационные компании попарно договариваются о правилах тарификации входящего и исходящего трафика, причём эта тарификация строится как функция от тарифов, которые компании предлагают своим абонентам за обслуживание. Таким образом, эти компании ограничиваются на первом шаге договорённостями по обоюдным правилам пропорциональной тарификации за доступ трафика (ОППТДТ), которые впоследствии позволяют определить тарифы для пользователей услуг мультисервисных сетей, которыми владеют компании. Обоюдность правил означает, что компании подчиняются одним и тем же правилам на всем интервале времени, в течение которого действует договорённость. С учётом несовершенной конкуренции на рынке телекоммуникаций и при условии максимизации прибыли каждой компанией, которая является поставщиком услуг, в рамках построенной модели были найдены равновесные тарифы на эти услуги с учётом перегрузок в мультисервисных сетях, а также объёмы этих услуг

Построение математической модели ценообразования на телекоммуникационные услуги с учётом перегрузок в сетях

This paper considers a model of dynamic pricing in the telecommunications market incomplete competition and taking into account overloads in multiservice networks. The model consists in the use of mathematical modeling methods, game theory and queueing theory. It is assumed that telecommunication companies agree on the rules of incoming and outgoing traffic charging in pairs, and this charging is built as a function of the tariffs that companies offer their subscribers for service. Companies are limited the agreement on mutual rules of reciprocal proportional charging for access traffic at first, which subsequently determine the tariffs for the multiservice network users. The reciprocity of the rules means that companies are subject to the same rules for the entire time interval during which the agreement is in force. Taking into account imperfect competition in the telecommunications market and using profit optimization method for each company the equilibrium tariffs and the volume of services are found with subject to congestion in multi-service networks.В работе строится модель динамического ценообразования на рынке телекоммуникаций при условии ограниченной конкуренции и с учётом перегрузок в мультисервисных сетях. Для построения и исследования модели был применён комплексный подход, заключающийся в использовании методов экономико-математического моделирования и теории массового обслуживания. В предлагаемой модели предполагается, что телекоммуникационные компании попарно договариваются о правилах тарификации входящего и исходящего трафика, причём эта тарификация строится как функция от тарифов, которые компании предлагают своим абонентам за обслуживание. Таким образом, эти компании ограничиваются на первом шаге договорённостями по обоюдным правилам пропорциональной тарификации за доступ трафика (ОППТДТ), которые впоследствии позволяют определить тарифы для пользователей услуг мультисервисных сетей, которыми владеют компании. Обоюдность правил означает, что компании подчиняются одним и тем же правилам на всем интервале времени, в течение которого действует договорённость. С учётом несовершенной конкуренции на рынке телекоммуникаций и при условии максимизации прибыли каждой компанией, которая является поставщиком услуг, в рамках построенной модели были найдены равновесные тарифы на эти услуги с учётом перегрузок в мультисервисных сетях, а также объёмы этих услуг

Insecticidal efficiency and safety of zinc oxide and hydrophilic silica nanoparticles against some stored seed insects

The present study was conducted to evaluate the insecticidal efficiency and safety of zinc oxide nanoparticles (ZnO NPs) and hydrophilic silica nanoparticles (SiO2 NPs) against: adults of rice weevil (Sitophilus oryzae L.); red flour beetle (Tribolium castaneum Herbst.) and cowpea beetle (Callosobruchus maculatus F.) results showed that, both ZnO NPs and hydrophilic SiO2 NPs exhibited a significant toxic effect (df, F and p < 0.5) against S. oryzae and C. maculatus at the highest concentration while T. castaneum showed high resistance against the two tested materials. At the end of the experiment, recorded mortality was: 81.6, 98.3 and 58.3% at the highest concentration used for each insect (0.3, 2 and 8 gm ⋅ kg–1 of SNPs with C. maculatus, S. oryzae and T. castaneum, respectively), while mortality was 88.3, 100 and 38.3% at the highest concentration used for each insect (0.6, 2.5 and 8 gm ⋅ kg–1 of ZnO NPs with C. maculatus, S. oryzae and T. castaneum, respectively). Both tested materials caused high reductions in F1-progeny (%) with C. maculatus and S. oryzae. Histopathological examination of male mice livers showed hepatic architecture with congested blood sinusoids, binucleated hepatocytes nuclei, dilated central vein and margainated chromatin in some nuclei. Histopathological assessment of the lungs showed normal histoarchitecture. There were no differences in alveolar septa, bronchiolar and epithelium of the treated and untreated animals. Silica and zinc oxide nanoparticles have a good potential to be used as stored seed protectant alternatives if applied with proper safety precautions

Abnormal meiotic behavior in three species of Crotalaria Comportamento meiótico anormal em três espécies de Crotalaria

The objective of this work was to compare the meiotic behavior and pollen grain viability of three species of Crotalaria. Slides for meiotic analysis were prepared by the air-drying technique. Pollen grain viability was measured by three staining procedures (Alexander's solution, tetrazolium chloride and fluorescein diacetate) and in vitro germination in a sucrose solution. Eight bivalents were observed, confirming previous reports on populations from other regions of Brazil, as well as from other countries. All species showed abnormal meiotic behavior as follows: in Crotalaria micans, cytomixis and abnormal chromosome pairing in diakinesis; in C. spectabilis, abnormal chromosome pairing in diplotene; in C. zanzibarica, shrunk nuclei in leptotene and zygotene. Pollen grains of all three species show low viability, which may be associated with the irregularities of the meiotic behavior.<br>O objetivo deste trabalho foi comparar o comportamento meiótico e a viabilidade dos grãos de pólen de três espécies de Crotalaria. A análise meiótica foi realizada por meio da técnica de secagem ao ar. A viabilidade dos grãos de pólen foi avaliada por testes de coloração (corante de Alexander, cloreto de tetrazólio e diacetato de fluoresceína) e por teste de germinação em solução de sacarose. Foram observados oito bivalentes, confirmando relatos prévios em populações de outras regiões do Brasil e de outros países. As três espécies apresentaram comportamento meiótico irregular: em Crotalaria micans, citomixia e pareamento irregular na diacinese; em C. spectabilis, pareamento irregular no diplóteno; e em C. zanzibarica, núcleo fortemente condensado nas fases de leptóteno e zigóteno. A viabilidade dos grãos de pólen das três espécies é baixa, o que pode estar associado às irregularidades do comportamento meiótico