Changes in plasma renin activity and renal immunohistochemically demonstrated renin in carbadox treated pigs

Carbadox is known to induce toxic effects on the adrenal cortex, resulting in hypoaldosteronism. To study the involvement of carbadox on the renin-angiotensin system, weaned piglets of five weeks old received feed supplemented with 0 (control group), 50, 100, 150 or 200 ppm carbadox. After four weeks the 100 and 150 ppm groups had significantly higher plasma renin activity levels than the control group and after nine weeks plasma renin activity levels of all treated groups were significantly higher than the control group. Five and 10 weeks after carbadox administration, three and two pigs, respectively, of all groups were necropsied and the kidneys were screened for immunohistochemically demonstrated renin. All dosed pigs demonstrated an increase of immunoreactive renin, which was dose- and time-related. From these results it is concluded that carbadox induces activation of the renin-angiotensin system, secondary to the suppressing effect on mineralocorticoid secretion and that these changes may be responsible for part of the clinical picture.     

Effect of GnRH and hCG administration on plasma LH and testosterone concentrations in normal stallions, aged stallions and stallions with lack of libido

Gonadotrophin-releasing hormone (GnRH) (a single intravenous injection with 0.042 mg busereline acetate) was administered to control stallions (n=5), aged stallions (n=5) and stallions with lack of libido (n=5). Jugular blood samples were taken at -10, 0, 10, 20, 40 and 80 minutes after treatment and measured for luteinizing hormone (LH) and testosterone concentrations. A single intravenous injection of hCG (3000 IE) was given 1 day later. Venous blood samples were taken at -60, 0, 15, 30, 60, 120, and 240 minutes after treatment and measured for the testosterone concentration. The experiment was performed in the breeding season. There was a wide variation between stallions in basal concentrations of LH and testosterone. The treatment groups all showed a significant increase in LH and testosterone concentrations after treatment with GnRH. There was a significant difference (P<0.05) between the control, the lack of libido stallions and the aged stallions in the production of LH before and after stimulation with GnRH. The aged stallions had higher basal LH concentrations. GnRH induced a rise in plasma LH in all groups, but the greatest response was observed in aged stallions. No response to GnRH was seen with respect to plasma testosterone. There was an increase in plasma testosterone following hCG; however, this increase was very small in aged stallions. After stimulation with hCG the control and lack of libido stallions had a significant increase (P<0.05) in testosterone production. In conclusion, stimulation with either GnRH or hCG can be a valuable method to test whether the function of the stallion's reproductive endocrine system is optimal.     

Non-pruritic granuloma in Norwegian forest cats

The eosinophilic granuloma complex is a group of skin disorders common in cats. This paper describes the clinical, haematological and histopathological features of 17 related Norwegian forest cats, six of which had a linear granuloma on the caudal thigh, three of which also had a granuloma on the lower lip, and one of which had a granuloma in combination with an indolent ulcer. The high prevalence of the disease in this population is suggestive of a genetic background.     

Bilirubin metabolism in canine hepatobiliary and haemolytic disease

Summary

The kinetics of unconjugated ₃H‐bilirubin are described in 25 healthy dogs and 35 dogs with spontaneous hepatobiliary or haemolytic disease, using a two‐compartment model. The bilirubin production rates from erythrocyte degradation (P_E), ineffective erythropoiesis (P_I) and catabolism of hepatic haemoproteins (P_I), were derived from the incorporation of ¹⁴C‐glycine into haemoglobin and stercobilin. These combined measurements permitted an integral survey of bilirubin metabolism in health and disease. The concentration of unconjugated bilirubin in plasma and its of total bilirubin levels were similar in hepatic and haemolytic disorders.

This was explained by the highly increased bilirubin production rates in both types of disease. In addition, the hepatic bilirubin clearance was severely impaired in fulminant hepatitis and in cirrhosis, and moderately decreased in the other hepatobiliary diseases and in primary haemolysis. The erythrocyte lifespan was reduced in all animals but one. In addition to haemolysis, the contribution of P_I and P_L was variable, and in two dogs P_L was the principle source of highly increased bilirubin production rates. These data indicate that the concentration of unconjugated bilirubin in plasma or its fraction of total pigments is unreliable in the discrimination of canine hepatobiliary disease from haemolytic disorders.     

Individual differences and repeatability of post-prandial changes of plasma-free amino acids in young horses

Few data are available on post-prandial changes of plasma amino acids (AAs) in horses and on the repeatability and the individual variance on different sampling days. The objective of the present study was to measure pre- and post-prandial concentrations of plasma AA in 10 yearling horses. Blood samples were taken on days 1 and 40 of the study before feeding of hay, oats and soya meal and over an 8 h post-prandial period in 2-h intervals. The plasma AAs were measured by high-pressure liquid chromatography after ortho-phthalaldehyde derivatization. Mean fasting concentrations of the AAs were not significantly influenced by the individuum and sampling day. Repeatability of the fasting AA levels in the individual horses on two different sampling days was only found for histidine, 3-methylhistidine, methionine, tryptophan and taurine. While the absolute post-prandial AA concentrations differed between sampling days, the relative changes were comparable. All AA concentrations except 3-methylhistidine increased after feeding by 13% to more than 200% of their fasting values if the combined data of both days were analysed. Four hours after feeding the concentrations of arginine, asparagine, lysine, leucine, isoleucine and threonine, decreased more than 20%. Histidine, methionine, phenylalanine, valine, tryptophan, glutamine, glycine, tyrosine and taurine concentrations decreased by less than 20%. Concentrations of aspartic acid, glutamic acid, ornithine, serine and citrulline remained elevated. Most AA approached the fasting concentrations at 8 h, only glycine increased between 6 and 8 h after meal and 3-methyl-histidine concentrations were constant throughout the entire period. In conclusion, the pre-prandial plasma AA in horses appeared less influenced by individuum or sampling day than post-prandial plasma AA concentrations. Therefore, plasma AA concentrations should be interpreted only under well-defined conditions, especially regarding the feeding regimen.     

Idiopathic gastric rupture in a Friesian foal

Acute idiopathic gastric rupture resulted in sudden death of a 4.5-months-old healthy Friesian foal. No morphological lesions were present which could explain the preceding gastric impaction. In this case hypodypsia may have been (partially) responsible for the impaction as only a mechanical drinking apparatus, unsuitably for horses, was available.     

在不使用抗生素的肉鸡中发现了抗生素耐药性菌株

禁止在家禽饲料中添加抗生素对于减少对人类健康有潜在威胁的耐药性细菌几乎没有作用。来自美国的一个科研小组通过研究得出了以上惊人的结论。