The influence of the degradability of concentrate protein in the rumen and of the lysine content of the concentrate on growth and feed efficiency in early-weaned calves.

In two feeding trials involving 96 rearing calves each and based on a 2 x 3 factorial design, a comparison was made between concentrates containing rapidly and slowly rumen-degradable protein and among concentrates with lysine 6, 7 and 8 g/kg or 7, 8 and 9 g/kg. In a third trial involving 84 animals, 2 feeds containing rapidly and slowly degradable protein were compared. Calves were weaned at 6 weeks and remained in the trial an additional 5 to 6 weeks. Concentrates were fed freely from 21 days old and in 2 trials after weaning the calves were fed according to a plan based on body weight. Hay or prewilted grass silage was given freely. Difference in protein degradability between feeds with rapidly degradable protein and those with slowly degradable protein was 28 and 36% in the second and third trials. Treatments involving concentrates with slowly degradable protein resulted in a higher daily weight gain. Feed efficiency was usually improved. Increase in lysine content of the concentrate from 6 to 8 g/kg or from 7 to 9 g/kg resulted in a significant linear rise in daily weight gain and a linear rise in feed efficiency. In 2 of the 3 trials intake of roughage (1 x prewilted grass silage, 1 x hay) was positively affected by presence in the concentrate of slowly degradable protein. Lysine content of the concentrate had no effect on roughage intake. (Abstract retrieved from CAB Abstracts by CABI’s permission

Lysine-behoefte van Peking-eenden

In een proef met Peking-eenden werd het effect getest van verschillende lysine-gehalten in het voer op de technische resultaten en de slachtkwaliteit

Methionine-behoefte van Peking-eenden

Onderzocht is het effect van verschillende gehalten verteerbare methionine + cystine in het voer op de technische resultaten en slachtrendementen van Peking-eenden

Ook bij eenden werkt fytase

Een belangrijk probleem in de eendenhouderij is de uitscheiding van fosfaat via de mest. Het is van belang de mineralen-aanvoer terug te dringen in verband met overschotheffingen. In een proef is gekeken of fytase -net als bij kippen- daarbij kan helpe

Bepaling fytase-effectiviteit in het startvoer van vleeseenden

Verslag van onderzoek naar de fosforbehoefte en fytase-effectiviteit bij vleeseenden t/m drie weken leeftijd. In dit artikel aandacht voor de bepaling van het effect van fytase in het startvoer op de beschikbaarheid van fosfor aan de hand van lichaamsgewicht, botbreuksterkte en botasgehalte op drie weken leeftijd

A novel in vitro model for the study of plaque development in atherosclerosis.

For the study of atherogenesis in vitro, coculture systems have been devised, in which two or more cell types can be cultured in close contact to each other. Herein, we describe a novel in vitro model that aims at the simulation of the morphology of a normal muscular artery allowing for the study of the initial events in atherosclerosis. Using a modified fibrin gel as a scaffold for the coculture of endothelial cells (ECs) and smooth muscle cells (SMCs), we generated an autologous in vitro model with a multilayer growth of SMCs (intima-like structure) covered by an endothelium. The production of extracellular matrix (ECM) could be visualized histologically and verified by (i) ascorbic-acid dependent secretion of procollagen I into the supernatant and (ii) deposition of collagens I and III as well as laminin in the gel as assessed by immunohistochemistry. By BrdU-incorporation and Ki67 expression, the SMCs exhibited minimal proliferative activity, even when the culture period was extended to 6 weeks. Lipoprotein insudation was investigated under simulated hypo-, normo- and hypercholesterolemic conditions through addition of 0.5, 1 or 2 mg/mL LDL to the medium with subsequent time and dose dependent insudation of LDL. When human monocytes were added to the culture medium, infiltration and foam cell formation of macrophages and SMCs as well as expression of interleukin-8 (IL-8) was demonstrated. The in vitro model of the human vascular wall described herein appears to be suitable for the study of pivotal events in atherosclerotic plaque development. The applicability for long-term culture, the ability to study cell-matrix interactions and the opportunities for histomorphological and immunohistochemical examinations represent additional advantages of this model