Israel José da Silva

Avaliação da qualidade da água e percepção higiênico-sanitária na área rural de Lavras, Minas Gerais, Brasil, 1999-2000

In addition to personal interviews, laboratory analyses were performed using 80 water samples from 45 rural areas that are crossed by the Agua Limpa and Santa Cruz streams close to the city of Lavras, southern Minas Gerais State. The results allowed comparing the quality of water used for agriculture and the identification of determinant factors. The Agua Limpa stream mostly crosses an area used primarily for housing and characterized by low schooling. Many houses are supplied by shallow water wells and have ordinary cesspits for human waste disposal. All springs are polluted. The Santa Cruz stream displays a different scenario. The land is used mostly for agricultural purposes. Most owners live in town, with widely varied levels of school, from none to university. The houses are supplied by surface water. Most of the springs are polluted. The perception by both home and land owners concerning quality of the drinking water is determined solely by the waters physical and organoleptic characteristics. Sanitary parameters are not taken into account. Moreover, there is no relationship between fecal contamination and the type of spring. Land use and anthropic activity are far more important than the type of spring for water quality.

Evaluation of performance of UASB reactor in swine wastewater treatment

This research presents the development and evaluation of a system for treatment of swine wastewaters constituted by slat settler, followed by upflow anaerobic sludge blanket (UASB) reactor, at full scale. The UASB reactor was completely made of masonry and reinforced concrete. The evaluation of the treatment system was carried out through samples collected in the influent and effluent from the settler and UASB reactor. The following parameters were analyzed: temperature, pH, alkalinity, total volatile acids (VFA), suspended solids (TSS), volatile suspended solids (VSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), according to the methods established by the Standard Methods (APHA, 1998). The mean results of COD and BOD removal were 93 and 92%, respectively. The mean concentrations of COD, BOD and TSS in the final effluent were 790, 1818 and 854 g L-1, respectively. The volumetric organic load (VOL) in the UASB reactor ranged from 1.1 to 17.5 kg COD m-3 d-1. The system slat settler-UASB reactor showed itself to be a promising alternative for the treatment of swine wastewaters.

Postnatal somatic cell proliferation and seminiferous tubule maturation in pigs: A non-random event

Although seminiferous tubule maturation in horses begins in the central area of the testis, this process is thought to occur randomly throughout the testis in most mammals. Studies in our laboratory revealed that the establishment of spermatogenesis may not be a synchronous event in the testicular parenchyma of pigs. The objectives of the present study were to evaluate the pattern of seminiferous cord/tubule maturation and the morphological and functional characteristics of testicular somatic cells during postnatal development in three regions of the pig testis: a) near the tunica albuginea (TA); b) in the transitional area between the seminiferous tubules and mediastinum (TR); and c) in the intermediate area (ID) between the TA and TR. Based on the diameter of seminiferous cords/tubules, nucleus size of Sertoli cells and fluid secretion, mainly at 90 and 120 d of age, seminiferous tubule maturation was more advanced in the ID and TR. The mitotic activity of Sertoli cells was higher (P<0.05) in the TR than the ID and TA at 7 and 120 d. Except for the mitotic index of the Leydig cells, which was lower (P<0.05) in the ID at 7, 30, and 180 d than in the TA and TR, other Leydig cell ebd points, e.g., individual cell size, nuclear volume, and cytoplasmic volume, were consistently higher (P<0.05) in the ID, suggesting that steroidogenesis was more active in this region during the period investigated. Overall, we inferred that Leydig cells in the ID may play a pivotal role in postnatal testis development in pigs and this type of cell is likely related to asynchronous testicular parenchyma development, with the transitional area providing the primary zone for growth of seminiferous tubules.

Desenvolvimento de um sistema de resfriamento e conservação de sêmen suíno

A container with controlled cooling rate from 37oC to 17 or 5oC was constructed for the preservation of boar semen. The container produced a cooling rate initially of -0.16oC/min for a final temperature of 17oC and of -0.17oC/min for a final temperature of 5oC. The cooling process, during cold shock temperatures (17oC - 8oC) was of -0.0049oC/min. The container temperature was stable for 53.58h at internal temperature of 17±1oC and for 43.32h at 5±1oC.

ISOLATION AND GENOTYPING OF CLOSTRIDIUM PERFRINGENS FROM FREE-LIVING SOUTH AMERICAN COATI (NASUA NASUA).

Abstract:   The importance of Clostridium perfringens for most wild animal species remains unclear. This study aimed to isolate and genotype C. perfringens in stool samples from free-living South American coati (Nasua nasua) in Brazil. Forty-six free-living N. nasua were trapped and stool samples were collected. Two different protocols for C. perfringens isolation were tested: direct plating onto selective agar and pre-enrichment in broth followed by plating in selective agar. Clostridium perfringens type A was isolated from 15 (32.6%) animals by direct plating and 36 (78.3%) animals by broth PE, and the rate of isolation was significantly different between these two methods (P < 0.01). Twelve of the 36 (33.3%) isolated strains by the PE protocol were positive for the β-2 toxin-encoding gene (cpb2) whereas the enterotoxin-encoding gene (cpe) and necrotic enteritis like-B toxin gene (netb) were not found. These results suggest that C. perfringens is commonly part of the microbiota of free-living coatis. Additionally, the use of a PE protocol appears to be essential for studies on C. perfringens in this species.

Avaliação de desempenho de lagoa de polimento para pós-tratamento de reator anaeróbio de manta de lodo (UASB) no tratamento de águas residuárias de suinocultura

The performance of a polishing pond for treating swine wastewater from an upflow anaerobic sludge blanket (UASB) reactor was evaluated. The system was assembled with a slat settler, followed by an UASB reactor, on a real scale, and a post-treatment pond, on a demonstration scale. The following parameters were analyzed: temperature, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), volatile suspended solids (VSS), total Kjedahl nitrogen (NTK), ammonia nitrogen (N-am.), organic nitrogen, total phosphorus, and total and thermotolerant coliforms. The polishing pond was highly efficient, removing an average of 58.9% of BOD, 60.1% of NTK, 57% of N-am., and 95.34% of thermotolerant coliforms.

Hepatozoon ssp. (Apicomplexa: Hepatozoidae) Infection and Selected Hematological Values of the Neotropical Rattlesnake, Crotalus durissus collilineatus (Linnaeus, 1758) (Serpentes: Viperidae), from Brazil

Abstract:  This study aims to establish the hematological values of Crotalus durissus collilineatus snakes captured in Brazil as well as to verify the effects of hematozoan infection on these snakes. Eighty-three blood samples were drawn from C. d. collilineatus specimens for analysis. The sample set was composed of 30 males and 30 females, recently caught from the wild, and 11 males and 12 females bred in captivity. Blood samples were used to determine red blood cell counts, white blood cell counts, thrombocyte counts, hematocrit values, hemoglobin concentration, and total plasma protein. Blood smears were used to diagnose Hepatozoon spp. infection and to calculate the parasitic load in the sample as well as the percentage of immature red cells. Results obtained for the wild-caught animals, with and without parasites, were compared among themselves and with the values obtained for the captive-bred animals. Hematological values for C. durissus were established. Wild-caught snakes had an infection rate of 38.3%, while no Hepatozoon sp. infection was detected in the captive-bred animals. The snakes which were not infected by the Hepatozoon sp. exhibited average weight, length, and weight–length ratios higher than those of the infected animals. An increase in immature red cells was noted in the Hepatozoon-infected snakes.

Avaliação in vitro da eficiência de inóculos no tratamento anaeróbio de efluentes líquidos de suinocultura

The effect of seeding material (treatments) upon degrading liquid waste of swine was evaluated at different hydraulic retention times (0, 30, 60, 90, 120, 150, 180 hours). A commercial seeding material according to the recommended manufacture dosage, three alternative seeding materials based on bovine manure, chicken manure, and domestic sewage, all of them applied at the dosage of 5ml/l, and a control treatment (without seeding material) were used. An entirely randomized design was set to study the subdivided fragments using three repetitions. After each detention time, the following analyses have been performed: pH, biochemical oxygen demand (BOD), chemical oxygen demand, total solids, total volatile solid, settling solids, air and liquid temperatures. The commercial and alternative seeding materials based on chicken waste promoted a higher reduction of BOD than the other ones, 68.5% and 67.5%, respectively.

Eficiência de lagoas de polimento no pós-tratamento de reator UASB no tratamento de águas residuárias de suinocultura

The performance of a post-treatment pond for treating swine wastewater from an UASB reactor was evaluated. The system was assembled with an anaerobic baffle reactor (RAC), followed by an UASB reactor (UASB) on a real scale, and a post-treatment pond on a demonstration scale. The following parameters were analyzed: pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), volatile suspended solids (VSS), ammonia nitrogen (N-am.), total phosphorus (Pt), total coliforms (CT) and Escherichia coli (E coli.). The post-treatment lagoons contributed efficiently to remove nutrients, organic matter and solids, providing an effluent quality for agricultural reuse or discharge into a body of water.

Tratamento de efluentes de abatedouro de frangos por meio de reator UASB seguido de filtro anaeróbio

O Brasil e um dos maiores produtores de aves do mundo e se destaca na exportacao de carne de frango, que tem papel relevante na economia do pais. Como resultado do crescimento da industria de processamento do frango, ha tambem um significativo aumento na geracao de efluentes. Uma alternativa interessante para o tratamento desses residuos sao os reatores anaerobios. Este trabalho teve como objetivo avaliar o desempenho do sistema reator UASB-Filtro anaerobio no tratamento de efluentes de abate de frangos. O estudo foi desenvolvido em um abatedouro avicola, situado na regiao metropolitana de Belo Horizonte, Minas Gerais. O sistema de tratamento foi composto por peneira estatica, caixa de gordura, reator UASB e filtro anaerobio. A vazao media diaria de efluentes do abatedouro foi de 30m³/dia. A carga orgânica aplicada no reator UASB foi de 0,71kg DQO/m³.d. O monitoramento do sistema foi realizado por meio de analises fisico-quimicas do afluente e dos efluentes da caixa de gordura, reator UASB e filtro anaerobio. Os parâmetros avaliados foram: temperatura, pH, demanda quimica de oxigenio (DQO), demanda bioquimica de oxigenio (DBO), solidos suspensos totais (SST), e solidos suspensos volateis (SSV). Os valores efluentes medios encontrados para DBO, DQO e SST foram 106, 290 e 56mg/L, respectivamente. A eficiencia de remocao do sistema para DBO variou de 83 a 99%, e para DQO de 50 a 98%. A eficiencia de remocao media de SST e SSV foi de 92%. Conclui-se que o sistema reator UASB seguido de filtro anaerobio apresentou alto desempenho na remocao de solidos e carga orgânica. Dessa forma, esses reatores tornam-se uma alternativa viavel para o tratamento de aguas residuarias de frigorificos, ja que oferecem bons resultados de remocao de poluentes.