Lighting programs for male and female meat quails (Coturnix coturnix) raised in equatorial region

The aim of the present study was to evaluate the effect of lighting programs for male and female meat quails raised in an equatorial region on performance and carcass traits. A total of 1,500 sexed quails (Coturnix coturnix) was distributed in a completely randomized design in a 2 × 3 factorial arrangement, with 2 sexes (male and female) and 3 lighting programs (natural, intermittent, and continuous) with 5 replicates of 50 birds. The lighting programs were applied in the period from 7 to 49 d of age, being natural (12 h and 30 min of natural light and 11 h and 30 min of dark), intermittent (12 h and 30 min of natural light and 5 h and 30 min of artificial light, alternating lighting periods with one h and 06 min and periods of darkness with one h and 12 min), and continuous (23 h of natural + artificial light and one h of dark). Regardless of lighting program, female quails were heavier than males, and birds subjected to natural light weighed less than those exposed to continuous and intermittent lighting programs. Quails exposed to intermittent and continuous light presented higher weight gain and feed intake, and worse feed conversion ratio compared to birds under a natural light regimen. It is concluded that in an equatorial region, it is possible to use a lighting program with only natural light for raising male and female meat quails from 7 to 49 d of age.

Agentes causadores de mastite e relações entre a CCS com a produção e com a composição do leite em vacas leiteiras

Este estudo teve por objetivo avaliar o efeito da prevalência de patógenos causadores de mastite e da contagem de células somáticas (CCS) sobre a produção e composição do leite. Amostras de leite de 1163 vacas da raça Holandesa com 30.97±10.22 kg·d-1 de produção de leite foram coletadas e avaliadas. Staphylococcus spp. foi o patógeno mais prevalente. No geral, o aumento da CCS reduziu a produção de leite e a concentração de lactose e aumentou a concentração de proteína. Coliformes tiveram uma relação diferente entre CCS e teor de proteína no leite. A relação entre CCS e concentração de lactose foi diferente para S. aureus e Streptococcus spp. Lactose e proteína bruta são os componentes do leite mais sensíveis à variação da CCS e esta relação é dependente da presença do patógeno.

D2 dopamine receptor regulation of learning, sleep and plasticity

Dopamine and sleep have been independently linked with hippocampus-dependent learning. Since D2 dopaminergic transmission is required for the occurrence of rapid-eye-movement (REM) sleep, it is possible that dopamine affects learning by way of changes in post-acquisition REM sleep. To investigate this hypothesis, we first assessed whether D2 dopaminergic modulation in mice affects novel object preference, a hippocampus-dependent task. Animals trained in the dark period, when sleep is reduced, did not improve significantly in performance when tested 24h after training. In contrast, animals trained in the sleep-rich light period showed significant learning after 24h. When injected with the D2 inverse agonist haloperidol immediately after the exploration of novel objects, animals trained in the light period showed reduced novelty preference upon retesting 24h later. Next we investigated whether haloperidol affected the protein levels of plasticity factors shown to be up-regulated in an experience-dependent manner during REM sleep. Haloperidol decreased post-exploration hippocampal protein levels at 3h, 6h and 12h for phosphorylated Ca(2+)/calmodulin-dependent protein kinase II, at 6h for Zif-268; and at 12h for the brain-derived neurotrophic factor. Electrophysiological and kinematic recordings showed a significant decrease in the amount of REM sleep following haloperidol injection, while slow-wave sleep remained unaltered. Importantly, REM sleep decrease across animals was strongly correlated with deficits in novelty preference (Rho=0.56, p=0.012). Altogether, the results suggest that the dopaminergic regulation of REM sleep affects learning by modulating post-training levels of calcium-dependent plasticity factors.

Aminoglycoside and nephrotoxicity

The effect of three aminoglycosides--gentamicin, netilmicin and amikacin--on renal acid excretion was studied in male rats treated with doses equivalent to those clinically used. The amikacin and netilmicin groups showed no important changes in the values of glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and U/P inulin ratio during normal and acidotic conditions. The gentamicin group, however, showed a clear tendency to decreases in these functional parameters even in normal conditions, a finding that reinforces the concept that gentamicin is more nephrotoxic than other aminoglycosides. During normal conditions net acid excretion (BH) did not change with any of the three tested drugs. However, after an acute acid load BH markedly fell regardless of the antibiotic used. The capacity to elevate the urine-blood pCO2 was preserved after an alcaline overload, suggesting that the distal tubule was not significantly affected by aminoglycoside treatment. These data suggest that the clinical use of aminoglycosides during metabolic acidosis deserves close attention due to the possible deleterious effect that can emerge as the result of an inappropriate retention of acid loads.

Effect of gentamicin on urinary acidification in the rat

The effect of gentamicin, an aminoglycoside antibiotic, on renal function and especially on acid excretion was studied in normal and acidotic rats. The doses used were 1 (G4) and 10 (G40) times the suggested human therapeutic dose on a weight basis. After 10 days of each treatment, the glomerular filtration rate (GFR) was unchanged in G4 but fell significantly (p less than 0.05) in G40. In the acidotic groups (AG4 and AG40) there was an accentuated reduction in GFR, renal plasma flow and urine/plasma insulin ratio. Normal rats showed a normal acid excretion even with the high-dose treatment but, in the acidotic group, there was a significant decrease in ammonia excretion. The amount of bicarbonate excretion was significantly elevated in those groups, leading to a greater urinary pH. These results indicate that acute metabolic acidosis enhanced the nephrotoxic effects of gentamicin and impaired the excretion of an acid overload.