Increased pancreatic islet mass is accompanied by activation of the insulin receptor substrate-2/serine-threonine kinase pathway and augmented cyclin D(2) protein levels in insulin-resistant rats

It is well known that glucocorticoids induce peripheral insulin resistance in rodents and humans. Here, we investigated the structural and ultrastructural modifications, as well as the proteins involved in beta-cell function and proliferation, in islets from insulin-resistant rats. Adult male Wistar rats were made insulin resistant by daily administration of dexamethasone (DEX; 1mg/kg, i.p.) for five consecutive days, whilst control (CTL) rats received saline alone. Structure analyses showed a marked hypertrophy of DEX islets with an increase of 1.7-fold in islet mass and of 1.6-fold in islet density compared with CTL islets (P < 0.05). Ultrastructural evaluation of islets revealed an increased amount of secreting organelles, such as endoplasmic reticulum and Golgi apparatus in DEX islets. Mitotic figures were observed in DEX islets at structural and ultrastructural levels. Beta-cell proliferation, evaluated at the immunohistochemical level using anti-PCNA (proliferating cell nuclear antigen), showed an increase in pancreatic beta-cell proliferation of 6.4-fold in DEX islets compared with CTL islets (P < 0.0001). Increases in insulin receptor substrate-2 (IRS-2), phosphorylated-serine-threonine kinase AKT (p-AKT), cyclin D(2) and a decrease in retinoblastoma protein (pRb) levels were observed in DEX islets compared with CTL islets (P < 0.05). Therefore, during the development of insulin resistance, the endocrine pancreas adapts itself increasing beta-cell mass and proliferation, resulting in an amelioration of the functions. The potential mechanisms that underlie these events involve the activation of the IRS-2/AKT pathway and activation of the cell cycle, mediated by cyclin D(2). These adaptations permit the maintenance of glycaemia at near-physiological ranges.

Reduced pancreatic β-cell mass is associated with decreased FoxO1 and Erk1/2 protein phosphorylation in low-protein malnourished rats

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

Effect of crude protein levels and organic selenium supplementation in the diets fed during the breeding season on reproductive parameters of red-winged tinamous (Rhynchotus rufescens)

There is little information on the nutrition of red-winged tinamous (Rhynchotus rufescens) reared in captivity, and their nutritional requirements still need to be determined. This study aimed at determining dietary crude protein requirements and testing four organic selenium supplementation levels in the diet of red-winged tinamous during the breeding season. Birds were housed in a conventional broiler house divided in 16 boxes with one male and three females each. Iso-energy (2800kcal ME/kg) pelleted feeds, based on corn and soybean meal, were supplied in tube feeders. In the first experiment, treatments consisted of four different diets containing different crude protein (CP) contents (15, 18, 21, or 24%) and in the second experiment, the four diets contained equal protein level (22.5%) and four different organic selenium levels (0, 0.2, 0.4, or 0.8ppm). Data were analyzed by the least square method. The best egg weight and eggshell thickness were obtained with 22.5% dietary CP. Organic selenium did not influence the studied reproductive traits of red-winged tinamous (Rhynchotus rufescens) males or females.

Brain and hepatic Hsp70 protein levels in heat-acclimated broiler chickens during heat stress

In the present study we have investigated the effects of heat acclimation on brain and hepatic Hsp70 protein levels and body temperature of broiler chickens in response to gradual heat stress. Two groups of broilers were raised up to 47 days of age under distinct temperature conditions: thermoneutral (TN, according to bird age) or hot environmental (HS, 31-33°C). At 46 days of age, the birds reared at high ambient temperature were transferred to thermoneutrality conditions. After 18 h, these birds and the birds reared at thermoneutral temperature were submitted to gradual heat stress in a climatic chamber so that environment temperature was increased from 28 to 40ºC at a rate of 2ºC/h. Colonic temperature was measured using a thermometer sensor probe at each two hours, and hepatic and brain tissues were collected immediately after slaughter in order to assess Hsp70 protein level by Western blotting analysis. The colonic temperatures of birds reared at high temperature increased steeply during the first 2 h of heat stress (1.06ºC/h) and more slowly thereafter (0.59ºC/h). Broilers reared at thermoneutral temperature showed a small increase in the first 4 h of heat stress (0.18ºC/h) and then colonic temperature increased sharply (0.72ºC/h). Nevertheless, both groups presented similar final colonic temperature by the end of the stress period. Hsp70 levels (ng Hsp70 µg total protein-1) did not change in the liver or brain of the birds reared at high temperature. on the other hand, both liver and brain Hsp70 levels increased significantly during heat stress in the animals reared at thermoneutrality, with a higher expression of this peptide in brain tissue.

Effects of energy and protein levels on egg quality and performance of laying hens at early second production cycle

One hundred sixty-two commercial 70-wk-old ISA Brown laying hens, previously subjected to induced molting by feed restriction, were distributed in a completely randomized design with 3 x 3 factorial arrangement (i.e., 3 metabolizable energy levels: 2,850; 2,950, and 3,050 kcal of ME/kg) and 3 protein levels (16, 18, and 20% CP), which totaled 9 treatments with 3 replicates of 6 birds each. Experimental diets were offered to birds after the feed restriction period. Performance and egg quality parameters were evaluated in 14-d intervals from the 4th to 12th weeks after forced molting for a total of 4 evaluation periods. Increases in dietary energy and protein levels did not improve performance or egg quality. The levels of 2,850 kcal of ME and 16% protein were sufficient for laying hens starting the second production cycle without decreasing their performance or egg quality.

Small intestine development of laying hens fed different fiber sources diets and crude protein levels

The objective of the presente study was to evaluate the effects on different dietary fiber sources and crude protein levels on the intestinal morphometry of commercial layers. Isa Brown® layers with 48 weeks of age were distributed in a completely randomized experimental design with a 3 x 2 + 1 factorial arrangement, resulting in seven treatments with seven replicates of eight birds each. At the end of the fourth experimental period (28 days each), birds were 64 weeks of age and were randomly chosen (two birds per replicate, totaling 14 birds per treatment), weighed and sacrificed by neck dislocation. Their intestine was dissected and the duodenum, jejunum and ileum were collected for subsequent analysis of intestinal morphometry. Treatments consisted of diets containing three different fiber sources (cottonseed hulls, soybean hulls or rice husks) and two crude protein levels (12% or 16%). Soybean hulls and 16% crude protein level promoted, in general, an increase in villus height and crypt depth in the three intestinal segments. In the duodenum, the control diet resulted in higher villus height and crypt depth relative to the diets containing fiber. In the jejunum, higher crypt depth values. In the ileum, dietary fiber increased villus height as compared to the control diet.

Carcass characteristics of broilers at 42 days receiving diets with phytase in different energy and crude protein levels

Objetivou-se, com este trabalho, estudar as características de carcaça e qualidade da carne do peito depois da inclusão de fitase em dietas para frangos de corte, com diferentes níveis de energia metabolizável aparente corrigida para nitrogênio (EMAn) e proteína bruta (PB) reduzida, suplementadas com aminoácidos essenciais seguindo o conceito de proteína ideal. Foram utilizados 1.500 frangos machos Cobb dos 22 aos 42 dias de idade com peso inicial de 833 ± 7 g e final de 2741 ± 48 g distribuídos em delineamento inteiramente casualizado em esquema fatorial 3x3+1 (três níveis de EMAn - 2950, 3100 e 3250 kcal/kg - e três de PB - 14, 16 e 18% - e um tratamento adicional - controle, sem fitase, com 3100 kcal/kg EMAn, 19,2% de PB e 0,4% de fósforo disponível) em seis repetições com 25 aves cada. Ao final do experimento, duas aves de cada parcela foram sacrificadas para a mensuração do rendimento de carcaça e de cortes e determinação da composição química da carne do peito. Os níveis de energia e proteína em rações com fitase influenciaram (P<0,05) os rendimentos de carcaça, peito e gordura abdominal a porcentagem de umidade, proteína e lipídios no músculo pectoralis major das aves, sendo os níveis de 3100 kcal EMAn/kg e 18% de PB os que proporcionaram maiores rendimentos de carcaça e de peito e menor deposição de gordura abdominal, mas em maior teor de lipídios na carne do peito. Conclui-se que a manipulação da energia em rações com reduzido teor de proteína e suplementadas com aminoácidos e fitase influencia o rendimento de cortes e a qualidade da carne do peito de frangos aos 42 dias.

Protein levels for heat-exposed broilers: Performance, nutrients digestibility, and energy and protein metabolism

Heat stress causes significant economic losses on broilers production due to poorer performance and carcass quality. Considering that protein has the highest heat increment among nutrients, it has been suggested that protein levels should be reduced in diets for heat-exposed broilers. Nevertheless, there are no conclusive results on the benefits of such practice, and further studies should be performed to elucidate some reported discrepancies. Thus, a trial was carried out to evaluate the effects of dietary protein levels (17, 20 and 23%) and environmental temperature (22 and 32°C) on the performance, nutrients digestibility, and energy and protein metabolism of broiler chickens from 21 to 42 days of age. Nutrients digestibility was determined by total excreta collection, and energy and protein metabolism was evaluated by comparative slaughter method. It was concluded that (1) heat exposure impairs broilers performance and increases nitrogen excretion, but do not change nutrients digestibility; (2) high-protein diets are technically feasible and promotes lower heat production for broilers reared under thermoneutral or hot environments, however, high-protein diets increases nitrogen excretion. © Asian Network for Scientific Information, 2007.

Experimental infection of commercial layers with wild or attenuated Salmonella Gallinarum mutant strains: Anatomic pathology, total blood cell count and serum protein levels

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

Interleukin 4 haplotypes of susceptibility to chronic periodontitis are associated with IL-4 protein levels but not with clinical outcomes of periodontal therapy

Different IL4 haplotypes were associated to susceptibility to/or protection against chronic periodontitis (CP). The aim of this study was to investigate if individuals carrying different haplotypes would present differences in clinical periodontal parameters and in the IL-4 levels at baseline, 45 and 90 days after non-surgical periodontal therapy. 62 patients were subdivided: genetically protected without CP (PH), genetically protected with CP (PCP), genetically susceptible with CP (SCP), genetically susceptible without CP (healthy) (SH). Clinical examination and gingival crevicular fluid (GCF) collection were performed for all patients, and IL-4 levels were measured by ELISA. At baseline, higher values for plaque index (PI, p = 0.013), gingival index (GI, p = 0.005) were observed for the SCP group in comparison to the PCP group but not after the completion of periodontal therapy. 45 and 90 days after the non-surgical therapy, PCP demonstrated significantly higher IL-4 levels than the SCP (p = 0.000002). Correlation analysis showed different results between clinical parameters and IL-4 production or GCF volume for groups with different genetic loads. The IL4 gene which was previously associated with susceptibility to CP was related with differences in the IL-4 protein levels in the GCF. However, independent of genetic carriage, individuals responded similarly to this therapy. © 2013 American Society for Histocompatibility and Immunogenetics.

Treadmill Training Increases SIRT-1 and PGC-1 alpha Protein Levels and AMPK Phosphorylation in Quadriceps of Middle-Aged Rats in an Intensity-Dependent Manner

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Protein levels and environmental temperature effects on carcass characteristics, performance, and nitrogen excretion of broiler chickens from 7 to 21 days of age

This trial was conducted to evaluate the utilization of low-protein diets formulated based on the ideal protein concept for broiler chickens from 7 to 21 days of age reared at different environmental temperatures. Nine hundred male Cobb-500® chickens were used. At day seven chicks were distributed according to a completely randomized design in a 3 x 3 factorial with four replications of 25 birds each. It was used three crude protein levels in the diet (21.5; 20.0 and 18.5%) and three environmental temperatures (low, thermoneutral and high). The performance, carcass characteristics (yield and chemical composition), and nitrogen ingestion and excretion were assessed. There was no significant interaction among the factors for the evaluated variables. Environmental temperatures affected differently chicken performance. High environmental temperature resulted in lower weight gain and higher wing fat percentage, whereas cold temperature resulted in higher feed conversion. on the other hand, low-protein diets decreased weight gain, breast yield, nitrogen excretion and influenced breast and wings chemical composition. Birds reared at high environmental temperature showed lower nitrogen intake and excretion. The results showed that the decrease in protein levels from 7 to 21 days of age contributed to lower nitrogen excretion in broiler chickens, but impaired performance and carcass characteristics independent of rearing temperature.

DUCTAL CARCINOMA IN-SITU OF THE BREAST - HISTOLOGIC CATEGORIZATION AND ITS RELATIONSHIP TO PLOIDY AND IMMUNOHISTOCHEMICAL EXPRESSION OF HORMONE RECEPTORS, P53, AND C-ERBB-2 PROTEIN

Background. Ductal carcinoma in situ (DCIS) of the breast has been diagnosed increasingly since the advent of mammography. However, the natural history of these lesions remains uncertain. Ductal carcinoma in situ of the breast does not represent a single entity but a heterogeneous group with histologic and clinical differences. The histologic subtype of DCIS seems to have an influence on its biologic behavior, but there are few studies correlating subtype with biologic markers.Methods. The authors studied a consecutive series of 40 cases of DCIS and after its histologic categorization verified its relationship with ploidy using image analysis and analyzing estrogen receptor (ER), progesterone receptor (PR), p53 and c-erbB-2 expression using immunohistochemistry.Results. The three groups proposed according to the grade of malignancy were correlated significantly with some of the additional parameters studied, including aneuploidy and c-erB-2 expression. Aneuploidy was detected in 77.5% of cases of DCIS mainly in high and intermediate grade subtypes (100% and 80% vs. 35.7% in low grade) whereas immunoreactivity for c-erbB-2 was detected in 45% of cases of DCIS mainly in the high grade group. Expression of ER and PR were observed frequently in this study (63.9% and 65.7% respectively), but without correlation with the histologic subtype of DCIS, although we found a somewhat significant association between high grade DCIS and lack of ER. p53 protein expression was detected in 36.8% of these cases, but no relationship between this expression and histologic subtype or grading of DCIS was found.Conclusions. These results provide further evidence for the morphologic and biologic heterogeneity of DCIS. Besides histologic classification and nuclear grading, some biologic markers such as aneuploidy and c-erbB-2 expression constitute additional criteria of high grade of malignancy.

EXPRESSION OF C-ERB B-2 PROTEIN AND DNA-PLOIDY IN BREAST CARCINOGENESIS

Objective.-to examine the c-erb B-2 expression and nuclear DNA content in samples of breast lesions to ascertain any relationship between c-erb B-2 expression and aneuploidy in the different types of proliferative breast lesions and in intraductal and invasive carcinomas.Design and Setting.-lmmunohistochemical analysis of c-erb B-2 expression and cytometric nuclear DNA assessment were performed in a series of 39 cases of intraductal hyperplasia without atypia, 7 cases of intraductal hyperplasia with atypia, 64 cases of intraductal carcinoma, and 85 cases of invasive breast carcinoma (30 of which had extensive intraductal component).Results.-Overexpression of c-erb B-2 was seen only in cases of carcinoma: 28 (43.7%) intraductal carcinomas and 15 (17.6%) invasive carcinomas. Aneuploidy was demonstrated in 3 (43.0%) cases of intraductal hyperplasia with atypia, in 54 (84.4%) cases of intraductal carcinoma, and in 63 (74.2%) cases of invasive carcinoma. All cases of intraductal hyperplasia without atypia were euploid and none expressed c-erb B-2. Among the carcinomas (intraductal and invasive) there was a strong relationship between aneuploidy and c-erb B-2 expression. In most instances, the intraductal and invasive components of the 30 invasive carcinomas with extensive intraductal component displayed similar DNA content and c-erb B-2 immunoreactivity; whenever there was a difference, the intraductal component tended to be aneuploid (five out of six cases) and c-erb B-2 positive (one case), in contrast to the respective invasive component.Conclusions.-The higher frequency of aneuploidy and c-erb B-2 expression in intraductal carcinomas in comparison with invasive carcinomas suggests there is not a linear relationship between DNA content abnormalities and neoplastic progression and that some invasive breast carcinomas evolve without an identifiable intraductal phase or are unrelated to disturbances at the c-erb B-2 locus.

Low intensity laser therapy (LILT) in vivo acts on the neutrophils recruitment and chemokines/cytokines levels in a model of acute pulmonary inflammation induced by aerosol of lipopolysaccharide from Escherichia coli in rat

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