This study tested the hypothesis that the effect of lysine intake, if first-limiting, on protein retention in growing pigs is completely independent of the effects of energy intake, differences in the protein retention capacity among genotypes and gender, and body weight. Protein retention, using the nitrogen balance technique, was measured in 12 castrated male German Landrace and Pietrain pigs at 44 and 77 kg of BW and at two energy intake levels (1.1 and 1.3 MJ ME/kg BW.75). All animals received a constant amount of a basal diet that provided a protein intake of 220 g/d and a total lysine intake of 13 g/d. Appropriate amounts of cornstarch were offered additionally to reach the intended energy intake levels. The results show that neither energy intake nor breed had any effect on the level of protein retention, whereas, at 77 kg BW, protein retention was significantly lower than at 44 kg (117.8 and 123.5 g/d, respectively), which can be attributed to the higher requirement for maintenance. The results of this experiment and the linearity of the relationship between protein retention and lysine intake as shown by several authors simplify both the prediction of protein retention from lysine intake and the calculation of the lysine requirement for a particular protein retention. However, to ensure accuracy of these predictions, it is essential to know when ratios of lysine to other amino acids and to energy and capacity for protein retention in the animal become first-limiting.

Energy requirements for ingestion and standing were determined in open-circuit respiration chambers with four ruminally cannulated German Red Pied steers weighing 617 +/- 53 kg of BW (mean +/- SD). The requirement for standing over lying was derived by regressing heat production on time spent standing within 2-h periods when no feed was offered to avoid any interference with eating activity, and amounted to 14 kJ/(d x kg of BW). The energy requirement for ingestion was determined by calculating the difference between heat production during a 2-h period without feed and during a consecutive 2-h period in which straw of different particle sizes, fresh and conserved grass, or rolled barley were offered for ad libitum intake. Before measurements, the rumens of the steers were emptied, washed, and filled with a buffer solution to avoid heat production by metabolism of absorbed nutrients from the feed ingested during the experimental periods. The mean value for all feeds tested was 20 J/(min of ingestion x kg BW). Relating heat production to the amount of DM or fiber ingested did not decrease variation among feeds. This confirms the observations of earlier studies, that energy requirement for ingestion is mainly determined by time spent eating. Results of additional measurements, in which the same amounts of the respective feeds ingested in preceding periods were put into the emptied rumens via the cannulas, showed that the presence of the feed in the rumen did not increase heat production, indicating that the increment of heat production during eating is mainly caused by ingesting and chewing the feed. Further measurements in the same animals with an ingesta-filled rumen showed that ingestion of straw led to an increase in heat production per minute of chewing similar to those with emptied rumens, which confirms the validity of the experimental procedure using ruminally emptied animals to determine the energy requirement for ingestion.

Thrombosis is a recognised complication of inflammatory bowel disease (IBD), in particular venous thrombosis. Arterial thrombosis, especially stroke is rare. There is a paucity of information regarding stroke in IBD and its management. The authors describe two cases of stroke in patients with IBD during periods of increased disease activity. The literature regarding this devastating complication and the procoagulant state that exists in IBD are reviewed.

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Vagal afferent C-fibres from the heart constitute an important input to the neurogenic cardiovascular regulation. These fibres respond to altered cardiac filling pressures and to chemical stimuli. In rats, we tested whether cardiac vagal afferent C-fibres react exclusively to one stimulus (chemical or mechanical) or whether the fibres are bimodal, i.e. responsive to either kind of stimulus. As a mechanical stimulus, an indwelling balloon was inflated in the aorta to increase left ventricular end-diastolic pressure. The serotonin 5HT(3) receptor agonist phenylbiguanide was injected into the pericardial sac as a chemical stimulus. An increase of fibre activity by more than two standard deviations compared with control was considered a response to a stimulus. Most fibres (42 out of 57) responded to both stimuli and were categorized as bimodal, 9 fibres were solely mechanosensitive and 6 were solely chemosensitive. Hence, the majority of cardiac vagal C-fibres are likely to be bimodal, responding to both cardiac filling pressure and serotonin 5HT(3) receptor stimulation. Our results emphasize the potential role of endogenous mediators in the afferent limb of cardiac reflexes.