Ciclo reprodutivo do marisco-do-mangue Mytella guyanensis (Lamarck, 1819) no manguezal do Rio Tavares - Ilha de Santa Catarina/SC

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Aquicultura.O presente trabalho teve por objetivo estudar o ciclo reprodutivo do marisco-do-mangue Mytella guyanensis no manguezal do Rio Tavares, Ilha de Santa Catarina. Foram efetuadas 24 coletas quinzenais, de julho de 2002 a junho de 2003. Dos 480 indivíduos amostrados, 49% eram machos , 50% fêmeas, 0,2% hermafroditas e em 0,8% dos casos não foi possível identificar o sexo, devido à ocorrência de parasitismo. De acordo com a análise histológica, foram caracterizados os seguintes estágios do ciclo sexual: gametogênese, repleção de gametas, desova parcial, desova total e repouso (este último, observado somente em fêmeas). De um modo geral, a reprodução foi contínua, com a grande eliminação de gametas ocorrendo de agosto a outubro. Esta é a melhor época para proteção dos estoques naturais e para testes de fixação de larvas dessa espécie em coletores manufaturados

PRODUTOS NATURAIS DE ALGAS MARINHAS E SEU POTENCIAL ANTIOXIDANTE E ANTIMICROBIANO

Esta revisão de literatura teve como objetivo apresentar os produtos de algas marinhas disponíveis no mercado, as atividades antioxidante e antimicrobiana por elas apresentadas, os principais compostos envolvidos nessas bioatividades, além de aspectos fundamentais sobre a exploração e comercialização desses produtos naturais. Os dados descritos na literatura evidenciam o grande potencial das algas marinhas como fontes naturais de ingredientes funcionais. O estudo da composição química, além da descoberta dos mecanismos de ação que envolvem as atividades biológicas das diversas espécies de algas, será interessante fonte de dados para a exploração de novas drogas de interesse para as indústrias farmacêutica e de cosméticos, bem como de novos ingredientes funcionais para a indústria alimentícia

Shelf Life and Quality Study of Minced Tilapia with Nori and Hijiki Seaweeds as Natural Additives

The extraction of mechanically separated meat has emerged as an attractive process. However, it increases the incorporation of oxygen and, consequently, of flavors due to rancidity. Thus, preservatives must be added. The objective of this study was to evaluate the shelf life of minced tilapia to replace synthetic preservatives with Hijiki and Nori seaweeds extracts. The application of the extracts had no effect on the chemical composition of the minced tilapia. The seaweed extracts had inhibitory effect on total volatile base nitrogen. The minced tilapia complied with the microbiological standard set by Brazilin law. The panelists detected no differences in the rancid aroma and only minor differences were detected in the color of the products. It can be concluded that the minced tilapia with added seaweed extracts were within quality standards during frozen storage

DEVELOPMENT OF AN ELECTRONIC CONTROLLER FOR LETTUCE PRODUCTION IN GREENHOUSES

The objective of this study was to develop an electronic controller for microclimate control in greenhouses, as well as to verify if the automated control system affects the productivity of two varieties of lettuce “Lactuca sativa”. The control system was developed based on the Atmega 2560 and compatible transducers. An experimental field analysis was carried out over a production cycle for two lettuce varieties. The experimental results showed that the designed equipment worked according to the implemented programming algorithm. However, the ventilation, nebulization and shading actuators did not control environmental variables, due to under sizing. The irrigation process was correctly controlled throughout the experimental period. The electronic controller promoted increase in the productivity of lettuce varieties. There was increase of 28% in total fresh weight; 10% in stem diameter; 7 and 8% in height gain and average diameter, respectively

Can Road Tires be Applied in Agriculture?

The mechanization of crops causes problems in soil structure as it causes compaction. Compaction can be severe depending on the type of tire adopted in the field. Producers are concerned with selecting wheelsets that harm the soil less and remembering to save resources when buying agricultural tires. Agricultural tires are more expensive than road tires, and truck tires can be an alternative for producers to save money. The present study evaluated the interaction between wheelset and ground in a fixed tire testing unit, comparing the impact of different tire models on bare ground. The 6 treatments performed consisted of 3 tire models (p1: road radial, composed of double wheelset - 2×275/80r22.5; p2: agricultural radial - 600/50r22.5; and p3: agricultural diagonal - 600/50-22.5) versus two contact surfaces, one rigid and the other with bare agricultural soil. Seven response variables were used to apply Regression analysis and descriptive statistics. Agricultural tires applied less pressure to the soil, and the most significant resistance to soil penetration was obtained with the road tire, reaching severe compaction levels. We verified an increase in the contact area of the tires on a hard surface of 473% for p1, 417% for p2, and 625% for p3. Road tires must be applied in crops cautiously, as these models can cause more significant stress on the soil, especially in high humidity conditions.Federal University of Lavras - UFLAFederal University of Santa Catarina - UFSCState University of Mato Grosso - UEMSState University of São Paulo - UNESPState University of São Paulo - UNES

Road Tires Use inAgricultural Areas is Possible by Maintaining Soil Biomass

Brazil has a robust agricultural sector; however, the mechanization of crops causes several problems in the physical soil structure, including surface compaction. Compaction reduces crop productivity and producer profits. The intensity of compaction varies depending on the wheelset model used, tire type, water content, and soil load applied. Recent studies have shown that soil compaction in sugarcane can be attenuated by maintaining the vegetation cover (straw biomass) on the surface after harvesting. The present study used different tire models to evaluate the interaction between wheelset-soil as a function of different amounts of biomass left over from the sugarcane harvest. A physical simulation system (fixed tire testing unit) was used for the tests. The wheelsets were subjected to controlled loads on tanks with confined and standardized soil samples. The treatments consisted of 3 tire models (p1: road radial, composed of double wheelset - 2×275/80R22.5; p2: agricultural radial - 600/50R22.5; and p3: agricultural diagonal - 600/50-22.5) and three contact surfaces (s1: without vegetation cover; s2: soil with straw cover equivalent to 15mg ha-1; and s3: soil with 30Mg ha-1 vegetation cover), considering three replications. We performed principal component analysis (PCA) and regression analysis to results. We verified tire-soil contact area (CA) increased with the increase straw coverage and was inversely proportional to soil resistance penetration (PC). The highest resistance to soil penetration was obtained with the p1 tire on uncovered soil (s1). Road tires cause intense impact when no vegetation covers. We verified that intensity impact caused by the wheelsets in the crop would be determined by cover straw and tire model. For better results to soil preservation, it must maintain a minimum of 15Mg ha-1 of coverage biomass.Federal University of Lavras - UFLAFederal University of Santa Catarina - UFSCState University of Mato Grosso - UEMSState University of São Paulo - UNESPState University of São Paulo - UNES