Effect of caloric restriction on myenteric neuroplasticity in the rat duodenum during aging.

The objective of this study was to evaluate the effects of caloric restriction (CR) on myenteric neurons in the duodenum of Wistar rats during aging. Thirty rats were divided into three groups: the C group (six-month-old animals that were fed a normal diet from weaning until six months of age), the SR group (18-month-old animals that were fed a normal diet from weaning until 18 months of age) and the CR group (18-month-old animals that were fed a 30% CR diet after six months of age). After 12 months, the animals were euthanized. Whole-mount preparations of the duodenums were either stained with Giemsa or underwent NADPH-diaphorase histochemistry to determine the general myenteric neuron population and the nitrergic neuron subpopulation (NADPH-d+), respectively. The NADPH-d-negative (NADPH-d-) neuron population was estimated based on the difference between the Giemsa-stained and NADPH-d+ neurons. The neurons were counted, and the cell body areas were measured. Aging was associated with neuronal loss in the SR group, which was minimized by caloric restriction in the CR group. The density (mm(2)) of the Giemsa-stained neurons was higher in the SR group (79.09 ± 6.25) than in the CR (92.37 ± 11.6) and C (111.68 ± 15.26) groups. The density of the NADPH-d+ neurons was higher in the SR group (44.90 ± 5.88) than in the C (35.75 ± 1.6) and RC (39.14 ± 7.02) groups. The density of NADPH-d- neurons was higher in the CR (49.73 ± 12.08) and C (75.64 ± 17.05) groups than in the SR group (33.82 ± 4.5). In the C group, 32% and 68% of the Giemsa-stained myenteric neurons were NADPH-d+ or NADPH-d-, respectively. With aging (SR group), the percentage of nitrergic neurons (56.77%) increased, whereas the percentage of NADPH-d- neurons (43.22%) decreased. In the CR group, the change in the percentage of nitrergic (42.37%) and NADPH-d- (57.62%) neurons was lower. As NADPH-d- neurons will be mostly cholinergic neurons, CR appears to reduce the loss of cholinergic neurons during aging. The cell body dimensions (µm(2)) were not altered by aging or CR. Thus, CR had a protective effect on myenteric neurons during aging.

Effect of autoclaving diets use for growing rats: digestibility and performance - DOI: 10.4025/actascibiolsci.v26i1.1668 / Efeitos da utilização de ração autoclavada para ratos em crescimento: digestibilidade e desempenho - DOI: 10.4025/actascibiolsci.v26i1.1668

Experiments were carried out to evaluate the use of autoclaving diets for growing rats. To evaluate the performance, rats born from females receiving or not autoclaving diets during the gestation were distributed in a randomized experimental design, with two treatments and a one-animal experimental unit. The diet used for female rats in gestation did not influence the weight of the rats either at birth or during the weaning period. As for digestibility and performance assays, rats from both kinds of females (with and without autoclaving diets during gestation) were distributed in a 2x2 factorial outline (normal or autoclaving diets until weaning versus normal or autoclaving diets after weaning). There was a reduction in the digestive use of the autoclaving diet gross energy after weaning and a worsening in the alimentary conversion in the period up to 42 days. The protein solubility in KOH test is a good indicative of the diet"s nutritional quality loss

Foram conduzidos experimentos para avaliar o fornecimento de ração autoclavada ou não para ratos em crescimento. Para analisar o desempenho, ratos nascidos de fêmeas recebendo ração autoclavada ou não durante a gestação, foram distribuídos em um delineamento experimental casualizado com dois tratamentos e unidade experimental de um animal. A ração fornecida para ratas em gestação não influenciou o peso dos ratos ao nascer nem ao desmame. Nos ensaios de digestibilidade e desempenho utilizaram-se ratos oriundos de fêmeas que receberam ração autoclavada ou não na gestação distribuídos em um esquema fatorial 2x2 (ração normal ou autoclavada até a desmama versus ração normal ou autoclavada após a desmama). Evidenciou-se redução no aproveitamento digestivo da energia bruta da ração autoclavada fornecida após a desmama e piora na conversão alimentar no período até 42 dias. O teste de solubilidade da proteína em KOH é um bom indicador da redução da qualidade nutricional da ração