A note on sampling digesta from the ileum of broilers in phosphorus digestibility studies.

The responses of broilers to increments of dietary P concentration in P retention and P prececal digestibility were studied in 2 experiments using Ross 308 broilers in their fourth week of age. The low-P basal diet was mainly based on corn, potato protein, and corn starch. Titanium dioxide was used as the indigestible marker. Monobasic calcium phosphate was added in 6 (experiment 1) or 5 (experiment 2) graded levels up to a maximum of 8.1 g of P/kg of the diet. Five (experiment 1) and 6 (experiment 2) replicated pens of 10 birds were used. Excreta were collected from trays underneath the pens. Birds were asphyxiated by carbon dioxide exposure and the ileum (from Meckel's diverticulum to 2-cm anterior to the ileo-ceca-colonic junction) was dissected. Digesta was collected from the entire section (experiment 1) or from 3 subsections of equal lengths (experiment 2). Excretion of P increased linearly with increasing dietary P concentration up to a level of about 5.2 g of P/kg of the diet and increased nonlinearly with further increase in dietary P. In contrast, P flow in the ileum increased linearly over the entire range of P intake. Up to the level of 5.2 g of P/kg of the diet, P excretion was slightly lower than P flow in the ileum, but responses in P excretion and P flow in the ileum were similar, suggesting that P excretion with urine is very low and unaffected by P intake when the birds are supplied with P below their requirement. Between the 3 subsections of the ileum, calculated digestibility was significantly different for the basal diet and the diet with the 3 lowest levels of P supplementation. We concluded that the response in P prececal digestibility to increments in dietary P concentration is linear over a wider range of dietary P than the response in P retention. When digesta is collected from the ileum for determination of P prececal digestibility, the first third of the ileum should not be considered.

Treatment with Actovegin® improves sensory nerve function and pathology in streptozotocin-diabetic rats via mechanisms involving inhibition of PARP activation.

BACKGROUND: Diabetic neuropathy is one of the most severe complications of diabetes, affecting approximately one-third of diabetic patients. We investigated the potential neuroprotective effect of Actovegin®, a deproteinized hemoderivative of calf blood, in an animal model of diabetic neuropathy. METHODS: A single intravenous injection of streptozotocin (STZ, 55 mg/kg) was used to induce experimental diabetes in male Sprague-Dawley rats. Actovegin® (200 or 600 mg/kg) was administered intraperitoneally from day 11 to day 40 post-STZ exposure. N-acetylcysteine (NAC) was used as a positive control and was added to drinking water (0.2 g/l) from day 2 until day 40. Measurements to assess efficacy included sensory nerve conduction velocity (SNCV), intraepidermal nerve fiber density (IENFD), and poly(ADP-ribose) content. RESULTS: A decrease (35%) in sensory nerve conduction velocity (SNCV) was seen in STZ-induced diabetic rats from day 10 post-STZ administration and persisted at days 25 and 39. At study completion (day 41), a decrease (32%) in intraepidermal nerve fiber density (IENFD) was found in hind-paw skin biopsies from STZ-rats. Reduced SNCV and IENFD were significantly ameliorated by both doses of Actovegin®. More-over, 600 mg/kg Actovegin® markedly decreased poly(ADP-ribose) polymerase (PARP) activity in sciatic nerves from STZ-diabetic rats as assessed by poly(ADP-ribose) content. CONCLUSION: Actovegin® improved several para-meters of experimental diabetic neuropathy via mechanisms involving suppression of PARP activation, providing a rationale for treatment of this disease in humans.

Comparative studies with three-week-old chickens, turkeys, ducks, and quails on the response in phosphorus utilization to a supplementation of monobasic calcium phosphate.

We studied whether the availability of P is different among poultry species. A basal diet was mixed mainly based on corn, potato protein, and dried egg white. It was calculated according to the recommendations for young turkeys with the exception of P and Ca concentrations, which were deficient. Monobasic calcium phosphate (MCP) was added in graded levels, and analyzed P concentrations in the 7 diets were (in g/kg of dry matter) 2.9, 3.7, 4.5, 5.3, 6.2, 7.2, and 7.7. Four experiments were conducted with 3-wk-old broiler chickens, turkeys, ducks, and quails. Birds were kept in balance crates, and 8 individuals were allocated to each treatment diet. Birds were fed the treatment diets for 10 d, and excreta were quantitatively collected during the last 5 d. P utilization was calculated as the proportion of P intake that was accreted by the birds. The P accretion response of birds to incremental MCP intake was described with sigmoidal functions, and the marginal efficiency of P utilization ((delta)y/(delta)x) was calculated. Utilization of P from the unsupplemented basal diet was 58% in broilers, 55% in quails, 46% in ducks, and 39% in turkeys. Supplementation of MCP significantly increased P accretion in all species. Ninety-five percent of the estimated ymax in P accretion was achieved with 8.4, 7.3, and 4.8 g P/kg of dietary DM in broilers, ducks, and quails. No plateau in P accretion was achieved in turkeys. These differences correlate well with the differences in the feed/gain ratio, which was 1.3 in turkeys, 1.7 in broilers, 1.9 in ducks, and 3.5 in quails. The maximum in marginal efficiency of supplemented P was 96% in ducks, 81% in turkeys, 74% in broilers, and 77% in quails. These maxima were achieved at different levels of MCP supplementation. We concluded that differences in P availability exist between poultry species for plant and mineral P sources. Quails can be used as model species for broilers in P availability studies, but dietary P levels need special adjustment.

Linear regression approach to study amino acid digestibility in broiler chickens.

1. An experiment was conducted to investigate whether a linear regression approach is a suitable tool for determining the amino acid (AA) digestibility up to the terminal ileum of broiler chickens. Solvent-extracted rapeseed meal (RSM) was used as the model ingredient. 2. Ten diets with 5 different inclusion rates of RSM (60, 120, 180, 240 and 300 g/kg, corresponding to crude protein concentrations from 170 to 250 g/kg in the diet), each without or with a supplementation of phytase (500 U/kg), were fed ad libitum to broiler chickens between 14 and 21 d of age. Seven pens of 12 chickens were allocated to each treatment. Digesta were sampled on a pen basis from the section of the gastrointestinal tract between Meckel's diverticulum and 2 cm anterior to the ileo-caeco-colonic junction. Titanium dioxide was included as an indigestible marker. 3. The amounts of crude protein and AAs digested up to the terminal ileum constantly increased with increasing AA intake over the entire range of intakes. When the amount of an AA digested at the terminal ileum is linearly regressed against its intake, the deviation of the slope from 1 is caused by both the unabsorbed AA from RSM and from specific endogenous losses related to RSM. These slopes varied between 0.68 and 0.88 for individual AAs, and the slopes were unaffected by phytase supplementation. 4. It is suggested that a linear regression approach be adopted to study the AA digestibility of raw materials in chickens. Digestibility determined this way does not need any correction for basal endogenous loss.

Glutathione and peroxide metabolism in malaria-parasitized erythrocytes.

The glutathione metabolism of Plasmodium falciparum, P. vinckei and P. berghei has been investigated. Human erythrocytes with low glutathione reductase and synthetase activity are still capable of harbouring P. falciparum. Both enzymes have been demonstrated in Plasmodium spp. Moreover, evidence is given for a selenium-independent glutathione peroxidase in malaria parasites.