Physico - chemical chyme conditions and mineral absorption in broilers

In the Netherlands the efficiency of mineral absorption from the gastrointestinal tract of farm animals is a topic of interest to reduce the mineral concentration in animal manure. This study was done with broilers. It was focused on physico-chemical chyme conditions. These conditions were related to the absorption of minerals. Carboxy methyl cellulose was used as a model substance to affect the intestinal viscosities. Retention time parameters, pH and osmolalities were recorded. The site of mineral (Na, K, Ca, P, and Mg) absorption and apparent absorption values up to successive gastrointestinal segments were determined. Effects of the intestinal viscosity were verified using wheat-based broiler diets.Dietary inclusion of carboxy methyl cellulose (up to 1%) increased the intestinal viscosity, the mean retention time and decreased the ileal pH. The absorption of small osmo-active chyme components was reduced, which was reflected in less variable osmolalities as the chyme moved from the proximal small intestine onwards. The main site of mineral absorption is between the duodenum and the lower jejunum. In these segments the absorption is negatively affected by the inclusion of carboxy methyl cellulose in the diet. It was discussed that the intestinal viscosity was the main cause for this reduction in mineral absorption. Negative effects were partially compensated in the ileum. Similar effects were shown in wheat-based diets, but effects were less pronounced

Effecten van diermeel in het voer op gezondheid en welzijn van pluimvee en varkens

Productivity of poultry and pigs is similar or slightly improved by dietary inclusion of processed animal protein (PAP). In some studies it was demonstrated that gut health was improved by dietary inclusion of PAP. The risk for feather pecking and cannibalism in layers may be decreased by use of PAP. In all vegetable diets higher supplementation levels of free amino acids, minerals to the diet should be used in order to meet the nutrient requirements of the animals. Inclusion of PAP in compound feeds for poultry and pigs enlarges the matrix of ingredients rich in protein

Schatting van de uitscheiding van stikstof en fosfor door paarden, pony's en ezels

De vastlegging van N en P voor de verschillende diercategorieën is afhankelijk van de samenstelling van de diercategorieën, het volwassen gewicht van de dieren, en het aantal veulens dat per jaar wordt geboren. Op basis van de verschillende stamboeken (frequentieverdeling en volwassen gewicht per ras) zijn de gemiddelde gewichten van een volwassen dier per categorie bereken

Schatting van de uitscheiding van stikstof en fosfor door diverse categorieën graasdieren

Expertisecentrum LNV heeft de Animal Sciences Group benaderd met de vraag de forfataire stikstof (N)- en fosfor (P) excreties zoals die door Tamminga et al.(2000) voor een aantal diercategorieën zijn afgeleid te herberekenen en zo nodig bij te stellen, of deze af te leiden voor zover er nog geen excretiegetallen voorhanden zijn. Tevens is gevraagd voor zover relevant het aantal diercategorieën te verminderen

Ascites and venous carbon dioxide tensions in juvenile chickens of highly selected genotypes and native strains

A previous study by this group demonstrated that a high carbon dioxide tension in venous blood (pvCO2) of juvenile broiler chickens is a reliable predictor for ascites susceptibility. In a new experiment with five highly selected genetic stocks and two ascites resistant old breeds we studied levels and variability of pvCO2 within each stock at an early age. Effects of different selection traits (principally growth rate) between fast growing sire lines and slower growing dam lines and a commercial hybrid on blood gas (pCO2, pO2) tensions, pH and haematocrit in venous and arterial blood were examined at different ages and compared to values found in ascites resistant breeds. All birds were housed in floor pens in a climate controlled room and subjected to an ascites-predisposing cold environment. From each stock, 16 birds with the highest (high risk: HRc) and 16 birds with the lowest (low risk: LRc) pvCO2 values were selected at 12 days of age. These birds were marked for future blood sampling to determine changes in haematological characteristics with age and to relate these values to ascites susceptibility. At day 14, eight non-selected birds from each stock were randomly chosen for dissection to determine initial pulmonary arterial pressure index (API) values. Subsequently, all birds were allotted to 8 floor pens (13 birds per pen including two HRc and two LRc birds) per stock. Production performances from 104 birds per stock were measured from 16 to 33 days of age (feed intake (FI); feed conversion ratio (FCR); body weight (BW) at day 33). Mortality was recorded during the complete experimental period. At 5 wk of age, all HRc and LRc birds were necropsied and API values were recorded, which was used to classify the severity of the ascites syndrome. A convincing effect of pvCO2 values in juvenile chickens on API at 5 wk of age in modern lines confirmed results obtained in the previous study. At an early age, pvO2 values were much less predictive for high pulmonary pressure induced ascites at wk 5 than pvCO2 values. Hypercapnia combined with low blood pH values and followed by hypoxemia (inducing high haematocrit values) provoked a marked high incidence of ascites and high API values in modern breeds. A total absence of ascitic symptoms within native breeds corresponded with unchanged low API values during ageing from 12 to 33 days of age and with lower pCO2 values in venous and arterial blood compared to modern breeds at all ages. The pvCO2 difference (mean values) between HRc and LRc groups were similar for all modern lines irrespective of age and showed no relationship to growth rate. API, as a reliable indicator for ascites susceptibility, of modern breed chickens correlated with pvCO2 values, but not with growth rate. The high correlation between pvCO2 in juvenile chickens and API values at 5 wk of age indicated that a strong genetic selection pressure on low pvCO2 values at an early age will be an effective method to reduce decisively the occurrence of the ascites syndrome at sea level

Forced oscillations in a hydrodynamical accretion disk and QPOs

This is the second of a series of papers aimed to look for an explanation on the generation of high frequency quasi-periodic oscillations (QPOs) in accretion disks around neutron star, black hole, and white dwarf binaries. The model is inspired by the general idea of a resonance mechanism in the accretion disk oscillations as was already pointed out by Abramowicz & Klu{\'z}niak (\cite{Abramowicz2001}). In a first paper (P\'etri \cite{Petri2005a}, paper I), we showed that a rotating misaligned magnetic field of a neutron star gives rise to some resonances close to the inner edge of the accretion disk. In this second paper, we suggest that this process does also exist for an asymmetry in the gravitational potential of the compact object. We prove that the same physics applies, at least in the linear stage of the response to the disturbance in the system. This kind of asymmetry is well suited for neutron stars or white dwarfs possessing an inhomogeneous interior allowing for a deviation from a perfectly spherically symmetric gravitational field. We show by a linear analysis that the disk initially in a cylindrically symmetric stationary state is subject to three kinds of resonances: a corotation resonance, a Lindblad resonance due to a driven force and a parametric sonance. The highest kHz QPOs are then interpreted as the orbital frequency of the disk at locations where the response to the resonances are maximal. It is also found that strong gravity is not required to excite the resonances.Comment: Accepte