RESUMEN
Os resíduos provenientes da aquicultura são derivados da ração e da excreção dos peixes e podem estar sedimentados, suspensos ou dissolvidos, ocasionando elevados valores de DBO, DQO, nitrogênio e fósforo. A produção de camarões no Brasil tem gerado elevadas quantidades de resíduos sólidos, tendo em vista que os exoesqueletos dos camarões correspondem a cerca de 40% do seu peso total, resultando num forte impacto ambiental. Diversas pesquisas envolvendo a quitina estão sendo desenvolvidas na área de tratamento de água, devido principalmente a sua capacidade de formar filme, sendo utilizada em sistemas filtrantes. Este polissacarídeo também pode ser utilizado como agente floculante no tratamento de efluentes, como adsorvente na clarificação de óleos, e principalmente na produção de quitosana. Atualmente a quitosana possui aplicações multidimensionais, desde áreas como a nutrição humana, biotecnologia, ciência dos materiais, indústria farmacêutica, agricultura, terapia genética e proteção ambiental. A quitosana é muito eficiente na remoção de poluentes em diferentes concentrações. Apresenta alta capacidade e grande velocidade de adsorção, boa eficiência e seletividade tanto em soluções que possuem altas ou baixas concentrações. O uso da biotecnologia, através do processo de adsorção utilizando adsorventes naturais e baratos, como a quitina e quitosana, minimiza os impactos ambientais da aquicultura tanto em relação aos provocados pelo lançamento de efluentes no meio ambiente quanto aos causados pelo descarte inadequado dos resíduos do processamento de camarões.(AU)
Aquaculture residues are derived from fish feed and excretion and may be sedimented, suspended or dissolved, resulting in high BOD, COD, nitrogen and phosphorus values. Shrimp production in Brazil has generated high amounts of solid waste, since shrimp exoskeletons account for about 40% of their total weight, resulting in a strong environmental impact. Several researches involving chitin are being developed in the area of water treatment, mainly due to its ability to form film, being used in filter systems. This polysaccharide can also be used as a flocculating agent in the treatment of effluents, as an adsorbent in the clarification of oils, and especially in the production of chitosan. Currently, chitosan has multidimensional applications, from areas such as human nutrition, biotechnology, materials science, pharmaceutical industry, agriculture, gene therapy and environmental protection. Chitosan is very efficient in the removal of pollutants at different concentrations. It presents high capacity and high adsorption velocity, good efficiency and selectivity both in solutions that have high or low concentrations. The use of biotechnology, through the adsorption process using natural and cheap adsorbents such as chitin and chitosan, minimizes the environmental impacts of aquaculture both in relation to those caused by the release of effluents into the environment and those caused by the inappropriate disposal of processing residues of shrimps.(AU)
Los residuos procedentes de la acuicultura se derivan de la ración y de la excreción de los peces y pueden estar sedimentados, suspendidos o disueltos, ocasionando elevados valores de DBO, DQO, nitrógeno y fósforo. La producción de camarones en Brasil ha generado grandes cantidades de residuos sólidos, teniendo en cuenta que los exoesqueletos de los camarones corresponden a cerca del 40% de su peso total, resultando en un fuerte impacto ambiental. Varias investigaciones involucrando la quitina se están desarrollando en el área de tratamiento de agua, debido principalmente a su capacidad de formar película, siendo utilizada en sistemas filtrantes. Este polisacárido también puede ser utilizado como agente floculante en el tratamiento de efluentes, como adsorbente en la clarificación de aceites, y principalmente en la producción de quitosana. Actualmente la quitosana posee aplicaciones multidimensionales, desde áreas como la nutrición humana, biotecnología, ciencia de los materiales, industria farmacéutica, agricultura, terapia genética y protección ambiental. La quitosana es muy eficiente en la eliminación de contaminantes en diferentes concentraciones. Presenta alta capacidad y gran velocidad de adsorción, buena eficiencia y selectividad tanto en soluciones que poseen altas o bajas concentraciones. El uso de la biotecnología, a través del proceso de adsorción utilizando adsorbentes naturales y baratos, como la quitina y quitosana, minimiza los impactos ambientales de la acuicultura tanto en relación a los provocados por el lanzamiento de efluentes en el medio ambiente en cuanto a los causados por el descarte inadecuado de los residuos del procesamiento de camarones.(AU)
Asunto(s)
Quitina/administración & dosificación , Adsorción/efectos de los fármacos , Quitosano/administración & dosificación , Aguas Residuales/química , Biopolímeros/análisis , Acuicultura , Eutrofización/fisiología , Amoníaco/químicaRESUMEN
Oral administration of an antigen can result in local and systemic priming or tolerance and the basis of this dichotomy is poorly understood. The intestinal microenvironment, and factors such as nature of the antigen, dose, genetic background, uptake and concentration of the antigen that gain access to the internal milieu via the mucosa influence these active immunologic processes. Chitosan is a biocompatible natural polysaccharide able to promote the transmucosal absorption of peptides and proteins. The aim of our work was to study the effect of the co-administration of type II collagen (CII) and chitosan during the initial contact of the antigen with the immune system. Sixteen hours after feeding we evaluated several molecular events in mucosal and in systemic lymphoid tissues. We determined in Peyer's patches (PP) and spleen cells the number and activation of T cells, the arrival of the antigens, and the cytokine profile. In PP we found a reduction in the cell number without changes in CD3(+) cells. In spleen, instead, we observed an increase in CD3(+) cells as well as the internalization of the CD3 complex. CII:chitosan-fed animals exhibited a reduced secretion of IL-2 with an increase of IL-10 in PP and spleen respectively. In addition, in PP, CII:chitosan-fed rats showed increased levels of mRNA for transforming growth factor-beta, IL-4 and IL-10. Together, our data suggest that the co-administration with chitosan modifies the uptake and/or the distribution of the relevant antigen, and promotes an anti-inflammatory environment early after feeding.
Asunto(s)
Quitina/análogos & derivados , Quitina/farmacología , Colágeno Tipo II/farmacología , Citocinas/biosíntesis , Inmunidad Mucosa , Administración Oral , Animales , Complejo CD3/inmunología , Complejo CD3/metabolismo , Muerte Celular , Quitina/administración & dosificación , Quitina/metabolismo , Quitosano , Colágeno Tipo II/administración & dosificación , Colágeno Tipo II/química , Citocinas/genética , Femenino , Expresión Génica , Interleucina-10/análisis , Interleucina-2/análisis , Pepsina A/antagonistas & inhibidores , Pepsina A/química , Ganglios Linfáticos Agregados/inmunología , ARN Mensajero , Ratas , Ratas Wistar , Bazo/citología , Bazo/metabolismo , Linfocitos T/inmunología , Linfocitos T/metabolismoRESUMEN
1. An experiment was designed to evaluate the effects of the addition of shark cartilage (SC) or chitosan (CH) to layer diets on egg component weights, yolk lipids and hen plasma lipids. 2. Hy-Line laying hens (80) were used during a 56 d feeding trial. Treatments were: basal diet (BD), BD + 20 g/kg SC, BD + 30 g/kg SC, BD + 20 g/kg CH and BD + 30 g/kg CH. Eggs were analysed on d 14, 28, 42 and 56. 3. Egg weight and egg component weights were not affected by these treatments throughout the experimental period. 4. After 14d of experimental feeding, cholesterol levels were higher in eggs from birds given BD + 20 g/kg CH and BD + 30 g/kg CH than in those from birds given BD. 5. Furthermore, eggs from hens given BD + 20 g/kg SC or BD + 20 g/kg CH were higher in palmitic and stearic acids and lower in oleic acid than those from birds fed on BD. After 56 d feeding, however, palmitic and stearic acid contents in eggs from hens given any of the supplemented diets were lower than in those from hens given BD, and oleic acid in eggs from hens given BD + 20 g/kg SC, BD + 30 g/kg SC and BD + 30 g/kg CH was higher than in those from birds fed on BD. 6. Plasma cholesterol and triacylglycerol levels were not significantly affected by dietary treatment. 7. Shark cartilage or chitosan at up to 30 g/kg in layer diets did not affect egg component weights (yolk, white and shell) and total lipid contents. During the period from 42 to 56d of experimental feeding, diets containing up to 30 g/kg chitosan reduced egg yolk contents of cholesterol, palmitic and stearic acids and increased the content of oleic acid.
Asunto(s)
Alimentación Animal , Cartílago/química , Pollos/fisiología , Quitina/análogos & derivados , Quitina/administración & dosificación , Yema de Huevo/química , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Cartílago/metabolismo , Pollos/metabolismo , Quitina/farmacología , Quitosano , Colesterol/análisis , Relación Dosis-Respuesta a Droga , Ácidos Grasos/análisis , Femenino , Lípidos/sangre , Oviposición/fisiología , Distribución Aleatoria , TiburonesRESUMEN
In this work we evaluated the efficacy and safety of a bread formulation containing chitosan in dyslipidemic type 2 diabetic subjects. For this purpose a total of 18 patients were allowed to incorporate to their habitual diets 120 g/day of bread containing 2% (wt/wt) chitosan (chitosan group, n= 9) or standard bread (control group, n= 9). Before the study and after 12 weeks on the modified diet, the following parameters were evaluated: body weight, plasma cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglyceride, and hemoglobin A(1c) (HbA(1c)). Compared with the control group, the patients receiving chitosan-containing bread decreased their mean levels of LDL-cholesterol and significantly increased their mean levels of HDL-cholesterol at the end of the study. There were no significant differences in the body weight, serum triglyceride, and HbA(1c). These results suggest that chitosan incorporated into bread formulations could improve the lipoprotein balance similar to typical biliary salts trappers, increasing the HDL- and lowering the LDL-cholesterol, without changing the triglyceride levels. These results warrant further studies over a longer period of time to evaluate if a persistent improvement in levels of lipoproteins can be attained with this strategy.
Asunto(s)
Pan , Quitina/análogos & derivados , Quitina/administración & dosificación , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Diabetes Mellitus Tipo 2/dietoterapia , Hiperlipidemias/dietoterapia , Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Quitina/efectos adversos , Quitosano , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/complicaciones , Aditivos Alimentarios/farmacología , Aditivos Alimentarios/uso terapéutico , Hemoglobina Glucada/análisis , Humanos , Hiperlipidemias/sangre , Hiperlipidemias/complicaciones , Resultado del Tratamiento , Triglicéridos/sangreRESUMEN
The present clinical study was performed to comparatively assess the therapeutic effect of Low and High Molecular Weight Chitosan (LMWCh and HMWCh), hexetidine, triclosan. Plaque index, saliva buffering capacity and bacteriological controls for S. mutans and lactobacilli, were performed. The plaque and bacterial indices revealed statistically significant differences between groups. Buffering capacity was similar using, hexetidine, and triclosan, whereas it was maximum in 100% of the patients in the LMWCh and HMWCh groups. Only 0.5% HMWCh induced low activity of S. mutans in 100% of the patients and caused complete inhibition of lactobacilli growth. No changes were observed in the profile of salivary proteins. The present clinical study confirms the therapeutic efficacy of the chitosan as a bacteriostatic agent.
Asunto(s)
Antiinfecciosos Locales/administración & dosificación , Quitina/análogos & derivados , Quitina/administración & dosificación , Placa Dental/tratamiento farmacológico , Hexetidina/administración & dosificación , Triclosán/administración & dosificación , Adolescente , Adulto , Quitosano , Recuento de Colonia Microbiana , Placa Dental/microbiología , Método Doble Ciego , Femenino , Humanos , Lactobacillus/efectos de los fármacos , Masculino , Peso Molecular , Antisépticos Bucales/farmacología , Antisépticos Bucales/uso terapéutico , Saliva/microbiología , Streptococcus mutans/efectos de los fármacosRESUMEN
The ability of a novel chitosan formulation to influence gastrointestinal fat absorption in vivo was examined in a double-blind, placebo-controlled, crossover study by determining the content of total fat in feces in two groups of subjects. Twenty-nine normal healthy subjects were recruited for the study. Twenty-four participants completed the test period with the chitosan formulation, and 21 completed the placebo phase of study. During the placebo and the test periods, the subjects were administered six capsules three times daily 10 minutes before meals for three days and for the two days of the stool collection. A daily serving of six tablets of the test compound contained 2100 mg chitosan and 300 mg psyllium husk seeds. In respect to the baseline period, the test compound increased fat excretion significantly whether the test period preceded or proceeded the placebo period (p<0.02 and p<0.05 respectively). In contrast, essentially no changes were seen during the placebo loading periods. Compared to the difference between placebo period and its baseline period, a statistically significant increase in fecal fat excretion was observed over baseline following oral supplementation of a novel formulation of chitosan and psyllium husk seeds [+3.63 gm/day +/- 0.83 (SEM) vs. -0.15 gm/day +/- 0.94 (SEM) (p=0.004)]. The average daily increase in fecal fat of 3-4 grams over control could account for a decrease in calorie consumption of 30-40 kcal per day. A total of 19 subjects completed both parts of the study. Examining the data from these 19 subjects by ANOVA, it was found that the period when the test compounds were given was statistically significantly different from the placebo baseline, placebo experimental, and test baseline periods. Using multiple comparisons, it was ascertained that the novel formulation containing chitosan plus psyllium husk seeds increases fecal fat excretion.
Asunto(s)
Quitina/análogos & derivados , Quitina/administración & dosificación , Heces/química , Absorción Intestinal/efectos de los fármacos , Lípidos/análisis , Adulto , Quitosano , Estudios Cruzados , Grasas de la Dieta/farmacocinética , Fibras de la Dieta/administración & dosificación , Método Doble Ciego , Femenino , Humanos , Masculino , Obesidad/dietoterapia , Psyllium/administración & dosificaciónRESUMEN
The purpose of this study was to produce aspirin-impregnated microspheres of chitosan/poly(acrylic acid) copolymer in order to evaluate the release characteristics as a function of pH, simulating the fluids in the gastrointestinal tract. Chitosan microspheres were obtained by the coacervation-phase separation method, induced by the addition of a non-solvent (NaOH 2.0 M solution). The microspheres were cross-linked with glutaraldehyde, reduced with sodium cianoborohydride and grafted with poly(acrylic acid). The impregnation of aspirin into chitosan/poly(acrylic acid) copolymer microspheres was achieved by the dissolution of the drug in water:ethanol (2:1), which was adsorbed by the microspheres for 24h at 25 degrees C. The efficiency of aspirin impregnation was high (approximately 94%). The approach employed herein in the production of aspirin-impregnated microspheres using chitosan/poly(acrylic acid) can be a suitable drug-release control system.
Asunto(s)
Resinas Acrílicas/administración & dosificación , Aspirina/administración & dosificación , Quitina/administración & dosificación , Sistemas de Liberación de Medicamentos , Quitina/análogos & derivados , Quitosano , Concentración de Iones de Hidrógeno , MicroesferasRESUMEN
We have found that the addition of chitosan, a cationic polymer, on whole or skim milk produces destabilization and coagulation of casein micelles that takes place without changes in the milk pH or the stability of most whey proteins. The amount of lipids recovered in the chitosan-casein aggregates was similar or higher than that obtained with rennet or acid precipitation. Approximately 70% of milk Ca2+ (approximately 750 mg/L) was found in the chitosan-induced aggregates, which is 10 and 50% higher than the amounts observed with acid or rennet coagulations, respectively. Purified alpha, beta-, and kappa-caseins were extensively precipitated by different molecular weight chitosans at pH 6.8. The phosphate groups of caseins seem not to be relevant in this interaction because dephosphorylated alpha- and beta-caseins were equally precipitated with chitosans. Analysis by optical microscopy of the chitosan-casein complex reveals that the size of the aggregates increase as the molecular weight of chitosans increase. Hydrophobic and electrostatic interactions particpate in the association and coagulation of casein micelles with chitosans of different molecular weights. The phenomenon is observed over a broad range of temperature (4 to 70 degrees C) with a reduction in the concentration of chitosan needed to precipitate the caseins that parallels a reduction in the viscosity of the chitosan solutions. Taken together, the results indicate that the electrostatic interactions may contribute energetically to the association between the two biopolymers, but the hydrophobicity of the complex would be the key determinant in the overall energetics of the reaction.
Asunto(s)
Caseínas/análisis , Quitina/administración & dosificación , Micelas , Leche/química , Animales , Biopolímeros , Quelantes/administración & dosificación , Fenómenos Químicos , Química Física , Quitina/análogos & derivados , Quitosano , Coloides , Concentración de Iones de Hidrógeno , Peso Molecular , Electricidad Estática , Temperatura , AguaRESUMEN
The effect of chitin at the level of 5% in the diet on cholesterol absorption and metabolism was studied in Wistar rats fed on diet containing beef tallow (7%) and cholesterol (1%). When compared with pair-fed controls, rats fed on diet containing chitin had: (1) similar weight gain and feed efficiency, (2) lower apparent protein digestibility, (3) equivalent liver steatosis, (4) reduced levels of liver triglycerides and cholesterol, (5) similar levels of serum and fecal cholesterol, (6) higher excretion of triglycerides in feces.