Effect of heat stress on endotoxin flux across mesenteric-drained and portal-drained viscera of dairy goat.

This study was designed to evaluate the effect of heat stress on endotoxin flux across mesenteric-drained and portal-drained viscera of dairy goats. Three Saanen first lactation dairy goats were surgically fitted with indwelling catheters in the portal vein, the mesenteric vein and carotid, and were kept in thermal-neutral and then heat stress environment, for examining the effect of heat stress on endotoxin absorption and redox status. Average net absorption of endotoxin (EU/h) across mesenteric-drained viscera (MDV) and portal-drained viscera (PDV) during the whole period of heat stress increased by 279.05% and 227.92% in relation to thermo-neutral period. Plasma concentration of glutathione peroxidase (GSH-Px) and catalase (CAT) in mesenteric and portal vein, and that of superoxide dismutase (SOD) in mesenteric vein, increased significantly during heat stress. Main conclusions were: (i) net absorption of endotoxin in portal vein is mainly from non-mesenteric tissues both in heat stress and in thermo-neutral condition; (ii) heat stress may lead to the significant decrease in plasma SOD, GSH-Px, CAT flux across PDV and MDV, and the significant increase in endotoxin flux across PDV and MDV; and (iii) the increase in gastrointestinal permeability in dairy goats during heat stress may not be induced by the increase in oxidative stress.

Artérias dos estômagos de fetos de bovinos da raça Nelore / Stomach arteries in Nelore bovines

Foi pesquisado o comportamento dos ramos arteriais destinados aos estômagos de fetos de bovinos da raça Nelore. Foram utilizados 30 fetos, os quais tiveram suas artérias injetadas a partir da aorta com látex Neoprene e dissecadas. De acordo com as observaçöes realizadas, o rúmen recebia ramos arteriais (artérias ruminais) derivados da artéria esplênica, a qual supria também o retículo (artéria reticular) através de colateral originado a partir da artéria ruminal esquerda. O omaso recebia irrigaçäo sanguínea a partir da artéria gástrica esquerda, a qual emitia um ou mais ramos para os sacos craniais do rúmen, e na curvatura do abomaso dava origem a artéria gastroepiplóica esquerda. As artérias gástricas direita e esquerda e as artérias gastroepiplóicas direita e esquerda anastomosaram-se entre si, respectivamente na pequena e grande curvaturas do abomaso

The stomach of the Kafue lechwe (Kobus leche kafuensis).

The Kafue lechwe is endemic to the Kafue Flats area of Zambia. It is semi-aquatic in habit, feeding upon grasses above and below the waterline. The volume of the lechwe rumen is 17 L in the male and 14 L in the female. It has strong and definite pillars. The interior of the rumen is papillated except in the roof area and on the pillars. The omasum has more than 70 laminae which are papillated on the reticular end. The anatomy of the lechwe stomach is similar to the stomachs of other water dependent grazers such as Bohor Reedbuck, Waterbuck, Uganda Kob and Puku.

Partition of portal-drained visceral net flux in beef steers. 1. Blood flow and net flux of oxygen, glucose and nitrogenous compounds across stomach and post-stomach tissues.

1. Blood from chronic indwelling catheters in the caudal aorta and anterior mesenteric, gastrosplenic and hepatic portal veins was used to measure blood flow and net flux of oxygen, glucose and nitrogenous compounds across hepatic portal-drained viscera (PDV), post-stomach (anterior mesenteric-drained viscera (MDV] and stomach tissues of two beef steers (390 kg mean live weight). 2. Steers were fed in sequence on (1) chopped lucerne (Medicago sativa) hay (twelve meals/d), (2) chopped lucerne hay (two meals/d) and (3) a pelleted concentrate diet containing 780 g ground maize/kg (two meals/d). The lucerne hay and concentrate contained 26.5 and 16.8 g nitrogen/kg respectively. 3. Five measurements of net flux (blood flow multiplied by venous-arterial concentration differences (VA] were obtained hourly on 2 d for each dietary regimen, beginning 0.5 h before feeding at 08.00 hours. Blood flow was measured by downstream dilution of p-aminohippurate (PAH). 4. Blood flow across MDV averaged 42% of PDV blood flow (665 litres/h). 5. Net use of O2 across MDV accounted for 51% of net PDV use of O2 (920 mmol/h). This disproportionate use of O2 in relation to blood flow was due to greater VA for O2 across MDV than across stomach tissues. Dietary regimen had no effect on the proportions of PDV blood flow and net O2 consumption attributable to MDV or stomach tissues. 6. When lucerne was given, net glucose use across MDV represented 69% of PDV use (35 mmol/h). When concentrate was given, MDV glucose use switched to net absorption (29 mmol/h), reducing net PDV glucose use to 1 mmol/h. 7. When concentrate was given, net MDV absorption of alpha-amino-N (AAN) increased from 98 to 190 mmol/h, yet net PDV absorption (101 mmol/h) was not affected. Net stomach AAN flux increased from -7 to -69 mmol/h when concentrate was given, negating the increase in net MDV absorption. 8. Net absorption of ammonia-N across MDV represented 28 and 52% of net PDV absorption when lucerne and concentrate were given respectively. Net NH3-N absorption across PDV was lower when lucerne was given than when concentrate was given (295 v. 154 mmol/h), reflecting lower dietary N intake (153 v. 83 g/d). Net MDV absorption of NH3-N was not affected by diet. Net removal of blood urea-N (BUN) across PDV (101 mmol/h) was not affected by diet. Across MDV, BUN removal was lower when concentrate was given than when lucerne was given (32 v. 77 mmol/h).(ABSTRACT TRUNCATED AT 400 WORDS)

Partition of portal-drained visceral net flux in beef steers. 2. Net flux of volatile fatty acids, D-beta-hydroxybutyrate and L-lactate across stomach and post-stomach tissues.

1. Net flux of volatile fatty acids (VFA), D-beta-hydroxybutyrate (BOHB) and L-lactate across post-stomach (anterior mesenteric-drained viscera (MDV], stomach and total hepatic portal-drained viscera (PDV) tissues was measured in two beef steers (mean live weight 390 kg). 2. Net flux was measured while steers were fed, in sequence, on (1) chopped lucerne (Medicato sativa) (twelve meals/d), (2) chopped lucerne (two meals/d) and (3) a pelleted concentrate diet containing 780 g ground maize/kg (two meals/d). 3. Five hourly net flux measurements were obtained on 2 d for each dietary regimen, beginning 0.5 h before a meal delivered at 08.00 hours. Net flux was calculated as venous-arterial concentration differences (VA) multiplied by blood flow (measured by downstream dilution of p-aminohippurate (PAH]. 4. Stomach tissues accounted for 85 to over 100% of net VFA and BOHB appearance across PDV. Net appearance across stomach tissues represented 74% of net PDV L-lactate appearance. 5. When lucerne was given, there was net utilization of arterial acetate and BOHB across MDV. This MDV utilization may reflect acetate and BOHB use as an energy source or their incorporation into mesenteric fat. 6. When concentrate was given, more n-butyrate and n-valerate and less L-lactate appeared across PDV and less 3-methylbutyrate appeared across stomach tissues than when lucerne was given. Postprandial increases in VFA, BOHB and L-lactate net flux across PDV followed meal-feeding of lucerne. 7. On a net basis, the relative contribution of MDV tissues of total PDV net appearance of VFA and BOHB was small (less than 15%) in these steers.

[Ultrastructure of the subepithelial capillaries and venules in the forestomach of sheep]. / Ultrastruktura na subepitelialnite kapiliari i venuli v predstomashiiata na ovtsata.

Described is the ultrastructure of the subepithelial capillaries and venules in the forestomach, of sheep. The vessels have proved to be fenestrated, with an entire endothelial lining, the fenestrae being closed by a well contoured membrane (diaphragm). Certain differences were established in the wall of the subepithelial vessels of the individual compartments of the forestomach. The fenestral portions are usually located at the side that is closer to the basal epithelium, while within the deeper layers they are replaced by nonfenestrated endothelium. A well defined pericapillary space, full of cross, olblique, and longitudinal collagen fibres was found between capillaries and epithelial basal cells. There were a number of ultrastructural findings in the walls of the capillaries, venules, and epithelium, which could be referred to as morphologic indices of the active transport of metabolic substances.

Blood flow in the various compartments of the goat stomach.

Blood flow rates in the mucosa and muscularis sections of the rumen, reticulum, omasum and abomasum of conscious goats have been measured by using radioactive microspheres. Blood flow rates to the rumen mucosa in ml/100 g tissue/min were 33.56 +/- 4.5, 11.64 +/- 3.2 and 7.18 +/- 1.6 under control conditions and during adrenaline and noradrenaline infusions respectively. The flow to the rumen muscularis under similar conditions were 12.5 +/- 2.4, 4.08 +/- 1.3 and 3.14 +/- 0.5. In the fundic mucosa, the blood flow rates were 50.52 +/- 5.8, 14.74 +/- 3.7 and 12.66 +/- 2.6 while the flow rates to the fundic muscularis were 18.26 +/- 3.8, 6.62 +/- 1.8 and 5.58 +/- 1.6. The flow rates to the pyloric mucosa were 31.28 +/- 2.8, 4.29 +/- 2.2 and 3.84 +/- 0.5 while the flow rates to the pyloric muscularis were 14.61 +/- 2.4, 5.42 +/- 1.6 and 4.62 +/- 1.9 ml/100 g tissue/min. the blood flow rates to these varius sections under control conditions were significantly higher than during adrenaline and noradrenaline infusions (P < 0.001) respectively.