A non-invasive method for silencing gene transcription in honeybees maintained under natural conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interference of cage fish farm on diet, condition factor and numeric abundance on wild fish in a Neotropical reservoir

Historically, the ichthyofauna of large Brazilian rivers has been subject to anthropogenic interference, such as impoundments. Currently, cage fish farming systems are a new source of impact on aquatic ecosystems. The objective of this study was to characterise the impact of freshwater fish farms on the feeding of five species of Neotropical freshwater fish. Specimens of Astyanax altiparanae, Galeocharax knerii, Iheringicthys labrosus, Pimelodus maculatus and Plagioscion squamosissimus were sampled in areas around two systems of cage fish farming (CF), and two control areas (CT) that were not influenced by this activity. Results show that there were significant changes in the diet of trophic generalist species (A. altiparanae, P. maculatus and I. labrosus) accompanied by a related increase in the condition factor values of these species in cage areas. Trophic specialist species, such as the carnivorous fish species G. knerii and P. squamosissimus, presented small differences between the CF and CT areas with regard to diet and showed no differences in other analyses performed. In conclusion, cage fish farms can affect the natural diet of trophic generalist fish species, directly affecting the nutritional status (condition factor), where food wastes was found to be one of the principal items consumed by this trophic guild. Results indicate that these species are responsible for recycling a great quantity of organic matter transferred by this type of activity, which, along with local fishery activities, contribute to mitigation of associated processes of eutrophication. © 2013 Elsevier B.V.

Técnica de criação e parâmetros biológicos de Stegasta bosquella em amendoim

Studies with Stegasta bosquella in peanut crop are little explored by researchers, mainly by the need of obtaining, in the field, a large quantity of closed leaflets. Therefore, it was sought a way of rearing in a natural diet that facilitates the attainment of the insect. The research was developed at the Laboratorio de Resistencia de Plantas a Insetos (FCAV/Jaboticabal) (T: 25 +/- 2 degrees C, RH 60 +/- 10% and photophase: 12 hours) (Runner IAC 886). The rearing stock of was carried out by collecting caterpillars from the field and keeping them in flat bottom glass tubes until adult emergence and test performance. Caterpillars were individualized in Petri dish plates, lined with moistened filter paper, which contained closed and early opened leaflets, but closed with paper clips (imitating the closed leaflet). A randomized design with two treatments and 36 repetitions was used. After the pupae formation, they were separated into five couples and the adults were kept in transparent plastic cages containing a peanut stem with leaves for oviposition, and fed with a 10% honey solution. The duration and viability of the larval and pupal periods, male and female longevity with and without food, and fertility were evaluated. The two forms of larvae rearing (closed leaflet and leaflet closed with clips) did not influence on any of the studied parameters. Therefore, the rearing of S. bosquella becomes feasible in natural diet, which means there is no need to use the enclosed leaflets for this purpose, and implies the easiness for rearing.

Feeding preference of the South American endemic anomuran Aegla platensis (Decapoda, Anomura, Aeglidae)

In order to determine the feeding preference of Aegla platensis in streams and the importance of microorganisms in its detritivore diet, we carried out two experiments designed to evaluate the food preferences of A. platensis (1) among leaves with different levels of microbial colonization and (2) among insect larvae (Chironomidae, Simuliidae, Hydropsychidae) and microbially conditioned leaves. A. platensis preferred animal over plant food items; when only leaves were offered, this aeglid preferred the leaves with higher levels of microorganism conditioning.

Crescimento e digestibilidade de dietas com diferentes teores de fibra para a tartaruga-da-Amazônia - Podocnemis expansa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Intestinal mucosa development in broiler chickens fed natural growth promoters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Performance of broilers fed diets containing natural growth promoters

The present study evaluated the effect of different probiotics on the performance of broiler chickens. A thousand and fifty one-day-old male Cobb chicks were distributed in a completely randomized design in a 3 x 2 + 1 factorial arrangement (3 probiotics sources in the diet, 2 probiotics concentrations in drinking water and 1 control group), with 5 repetitions of 30 birds per parcel. The results showed better feed conversion (p<0.01) (1-21, 22-35 and 1-45 days) and weight gain (p<0.05) (22-35 and 1-45 days) in the control group in relation to the groups receiving probiotics. The use of Bacillus subtilis in the diet improved (p<0.05) feed conversion during the growing phase, but this was not seen in the following period. Thus, it was concluded that probiotics supplementation had no beneficial effects on the performance.

Diet-induced obesity in rats leads to a decrease in sperm motility

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Natural killer activity in a medium-term multi-organ bioassay for carcinogenesis

Natural killer (NK) cell activity was evaluated after the initiation and promotion steps in a medium-term multi-organ bioassay for carcinogenesis. NK cell activity was assessed in vitro by Cr-51 release assay at the 4th and 30th weeks of the experiment. Male Wistar rats were sequentially initiated with N-diethylnitrosamine (DEN i.p.), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN drinking water), N-methyl-N-nitrosourea (MNU i.p.), dihydroxy-di-N-propylnitrosamine (DHPN drinking water) and N,N'-dimethylhydrazine (DMH s.c.) at subcarcinogenic doses for 4 weeks (DMBDD initiation). One group was evaluated at the 4th week and the other was maintained without any further treatment until the 30th week. Two initiated groups were exposed through the diet to 2-acetylaminofluorene (2-AAF) or phenobarbital (PB), from the 6th until the 30th week, Five additional groups were studied to evaluate the effects of each initiator on NK activity. All groups submitted to initiation only, initiation plus promotion, or promotion only, developed significantly more preneoplastic lesions than the untreated control group. The main target organs for tumor development in the initiated animals n ere the liver and the colon, irrespective of treatment with 2-AAF or PB. NK cell activity was not affected bal exposure to genotoxic carcinogens after initiation, at the 4th week. Treatments only with PB or 2-AAF did not change NK cell activity, However, decreased NK cell activity was registered in the group only initiated with DMBDD and in the group given DMBDD+2-AAF. This late depression of NK cell activity at the 30th week could be related to the production of suppressing molecules by the tumor cells.

Infiltrating CD8(+) T lymphocytes, natural killer cells, and expression of IL-10 and TGF-beta 1 in chemically induced neoplasms in male Wistar rats

The present study aimed to estimate the number of CD8(+) T and natural killer (NK) infiltrating cells and the expression of interleukin-10 (IL-10) and transforming growth factor beta 1 (TGF-beta1) in chemically induced neoplasms in an initiation-promotion bioassay for carcinogenesis. Male Wistar rats were treated with N-nitrosodiethylamine, N-methyl-N-nitrosourea, N-butyl-N-(4-hydroxybutyl) nitrosamine, dihydroxy-di-N-propylnitrosamine, and 1,2-dimethylhydrazine for 4 weeks. Two groups were subsequently exposed through diet to phenobarbital (0.05%) or 2-acetylaminofluorene (0.01%) for 25 weeks. An untreated group was used as a control. Immune cells and cytokines were immunohistochemically evaluated in neoplasms and in surrounding normal tissues at the liver, kidneys, lung, and small and large intestines. When compared to the respective normal tissues, an increased number of NK cells was verified infiltrating the colon, lung, and kidney neoplasms, while the number of CD8+ T cells decreased in the intestine and lung neoplasms. Expression of IL-10 was found mainly in kidney tumors. TGF-beta1 was expressed mainly in the liver and kidneys tumors. The results indicate that the differential occurrence of immune cells between neoplastic and normal tissues could be dependent upon tumor microenvironment.

Stable carbon (delta(13)C) and nitrogen (delta(15)N) isotopes as natural indicators of live and dry food in Piaractus mesopotamicus (Holmberg, 1887) larval tissue

This study proposed the use of the stable isotope technique to track the type of food utilized by pacu Piaractus mesopotamicus larvae during their development, and to identify the moment when the larvae start using nutrients from the dry diet by retaining its carbon and nitrogen atoms in their body tissues. Five-day-old pacu larvae at the onset of exogenous feeding were fed Artemia nauplii or formulated diet exclusively; nauplii+formulated diet during the entire period; or were weaned from nauplii to a dry diet after 3, 6 or 12 days after the first feeding. delta(13)C and delta(15)N values for Artemia nauplii were -15.1 parts per thousand and 4.7 parts per thousand, respectively, and -25.0 parts per thousand and 7.4 parts per thousand for the dry diet. The initial isotopic composition of the larval tissue was -20.2 parts per thousand and 9.5 parts per thousand for delta(13)C and delta(15)N respectively. Later, at the end of a 42-day feeding period, larvae fed Artemia nauplii alone reached values of -12.7 parts per thousand and 7.0 parts per thousand for delta(13)C and delta(15)N respectively. Larvae that received the formulated diet alone showed values of -22.7 parts per thousand for delta(13)C and 9.6 parts per thousand for delta(15)N. The stable isotope technique was precise, and the time at which the larvae utilized Artemia nauplii, and later dry diet as a food source could be clearly defined.

Natural killer activity in the experimental privational rickets

To study the 'in vivo' importance of vitamin D on the natural killer (NK) activity, rats were submitted to privational rickets induced by a diet deficient in vitamin D and phosphorus (D-P-). Thirty days after the beginning of treatment the animals showed low body weight, changes in the bone development, and decreased levels of 25-hydroxyvitamin D-3 (25-OH D-3). NK activity, evaluated using a cytotoxicity assay against Cr-51-labeled Yac.1 target cells, was not modified by the rickets-inducing treatment during the first 30 days. Following a long-term treatment (60 days) the rachitic rats (D-P-) exhibited higher NK activity than control animals (D + P +) (P < 0.05). on the other hand, D - P + animals showed higher cytotoxic activity than D - P - and D + P + groups. Feed replacement to the rachitic rats by a complete diet (D - P - /D + P +) led to a partial recuperation of growth, bone development, and 25-OH D-3 scrum. levels. The NK activity was also influenced by vitamin D intake, decreasing after treatment. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Natural history of the South American water snake Helicops leopardinus (Colubridae : Hydropsini) in the pantanal, Central Brazil

The South American water snake Helicops leopardinus is very abundant in the Pantanal wetlands of Central Brazil. We studied the biology of this species based on specimens collected by local workers in the Paraguay River. Females attained greater body lengths and had larger heads than males, but the latter had longer tails. Helicops leopardinus fed on a wide variety of fishes (70% of the total prey items) and frogs, with fishes of the order Gymnotiformes (33.34%) and frogs of the family Hylidae (23.34%) representing the most common prey items. There was relatively lows diet overlap between the sexes and between juveniles and adults. Mean litter size was 6.6 and ranged from 4-11. The reproductive cycle was seasonal, with birth occurring late in the wet season (simultaneous with the flooding of the Paraguay River), facilitating dispersal of young snakes by floating vegetation. Floating vegetation may be a critical habitat for H. leopardinus, and management plans for their maintenance need to be developed.

Uranium levels in the diet of São Paulo City residents

Natural levels of uranium in the diet of São Paulo City residents were studied, and radionuclide concentrations were measured by the fission track method on samples of typical adult food items. This information was used to evaluate the daily intake of uranium in individuals living in São Paulo City which is, according to our findings, around 0.97 mu g U/day. Using the ICRP Uranium-model, we estimated the uranium accumulation and committed doses in some tissues and organs, as function of time. We compared the output of the ICRP uranium biokinetic model, tailored for the conditions prevailing in São Paulo, with experimental data from other localities. Such comparison was possible by means of a simple method we developed, which allows normalization among experimental results from different regions where distinct values of chronic daily intake are observed. (c) 2006 Elsevier Ltd. All rights reserved.

EFFECTS OF PROTEIN-DEFICIENCY AND NATURAL INTESTINAL INFECTION WITH GIARDIA-LAMBLIA ON JEJUNAL INTRAEPITHELIAL LYMPHOCYTES IN RATS OF DIFFERENT AGES

1. The interaction between experimental protein deprivation and natural intestinal infection by Giardia lamblia was studied in terms of its effects on the intraepithelial lymphocyte (IEL) population and morphology of the jejunal mucosa of rats of different ages.2. Young, adult and old male Wistar rats received a protein-deficient diet (2% casein) or a control diet (20% casein) for 42 days. Mucosal height and the number of lymphocytes located among 500 consecutive epithelial cells (EC) along the villi or crossing the basement membrane were determined in PAS-stained jejunal fragments.3. The number of IEL increased progressively with animal age, from 14 to 25 per 100 epithelial cells, with significant differences between age ranges. However, the number of IEL did not differ between control and protein-deficient rats in any of the age groups. The proportion of lymphocytes crossing the basement membrane was approximately two-fold greater in young (2.8/100 EC) and adult (5.8/100 EC) protein-deficient animals than in their respective controls (1.6 and 2.8/100 EC). The intensity of parasite colonization was moderate, from 3 to 5/100 EC and did not differ between groups. The pattern of morphologic changes of jejunal mucosa in protozoal infection did not differ between control and protein-deficient animals in any of the three age groups.4. We conclude that intestinal infection with Giardia lamblia probably stimulated the local immune response, masking the reduction of the IEL population induced by protein deficiency. The increase in lymphocyte numbers with age may be related to prolonged antigenic stimulation promoted by infection.