Development of an arterial thrombosis model in pigs for investigating the thrombogenicity of different dietary fats

A surgically induced model of arterial thrombosis in pigs (60–80 kg live weight) has been developed using a balloon angioplasty technique. The purpose of this model is to assess the thrombogenicity of milkfat in comparison with other dietary lipids, thereby assessing its importance in the pathogenesis of human coronary heart disease. Balloon angioplasty catheters (Meditech, 3 cm X 8 mm balloon) are inserted into the left and right femoral arteries via a cut-down on to the saphenous artery. The balloons are inflated five times for 30 seconds with 30 second intervals between inflations. This results in endothelial denudation, exposure of sub-endothelial connective tissue and formation of platelet rich thrombi. Thrombus size is quantitated using autologous blood platelets labelled with ⁹⁹Tc-HMPA0 (technetium - “Deretec”).     

Leptospirosis in a lamb

Abstract

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Recently, we reported on outbreaks of Leptospira interrogans serovar pomona infection in newly weaned lambs(1) Vermunt, JJ, West, DM, Cooke, MM, Alley, MR and Collins-Emerson, J. 1994. Observations on three outbreaks of Leptospira interrogans serovar pomona infection in lambs. New Zealand Veterinary Journal, 42: 133–6. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]. It was suggested that wet environmental conditions played an important role in the pathogenesis of the disease in that class of sheep. This communication presents observations on another case of ovine leptospirosis, one that occurred under different circumstances, i.e. different season, age and environmental conditions.     

Clinical hypocalcaemia associated with Yarr (Spergula arvensis) ingestion

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Spergula arvensis (Spurrey, known locally as Yarr) is a fine- stemmed, viscid, erect or sprawling annual up to 30cm tall, with small white flowers and narrow, needle-shaped leaves in whorls at each stem node. It is a common weed of recently cultivated pastures. We have found no record of toxicity associated with ingestion of this plant, apart from a suggestion of illness when fed to caged birds (Roy et al., 1998). One of the authors (JDH) can recall a calcium-responsive recumbency in a small number of ewes grazing a poorly established swede crop in summer in which Yarr was the predominant green feed available.     

Granulosa cell tumour: An interesting case in a pregnant mare

This report describes the successful management of a pregnant 14‐year‐old seven‐eighths Thoroughbred mare with an ovarian granulosa cell tumour. The mare initially presented with unilateral ovarian enlargement whilst being managed for artificial insemination, demonstrating normal ovarian function with ovulation from the contralateral ovary leading to conception. The mare subsequently re‐presented with stallion‐like behaviour at 3.5 months gestation and ovarian suppression was evident. The mare maintained her pregnancy and delivered a live colt foal at term. Ovariectomy was performed 3 months post foaling and the mare regained cyclic activity 9 months post surgery. The mare then conceived and became pregnant once more. The diagnostic and therapeutic challenges during pregnancy are discussed.     

Caecal lipomatosis as a cause of colic in a 9‐year‐old gelding

Lipomatosis is an uncommon cause of colic. This case report details the pre‐ and intraoperative findings of a 9‐year‐old gelding, presented with acute abdominal pain. Exploratory laparotomy revealed a massive fatty infiltrate involving an extensive portion of the base and mid‐body of the caecum. To the authors' knowledge, this is the first report of an infiltrative lipomatous lesion of the equine caecum.     

Early postmortem biochemical factors influence tenderness and water-holding capacity of three porcine muscles

The objective of this study was to determine whether differences in pork tenderness and water-holding capacity could be explained by factors influencing calpain activity and proteolysis. Halothane-negative (HAL-1843 normal) Duroc pigs (n = 16) were slaughtered, and temperature and pH of the longissimus dorsi (LD), semimembranosus (SM), and psoas major (PM) were measured at 30 and 45 min and 1, 6, 12, and 24 h postmortem. Calpastatin activity; mu-calpain activity; and autolysis and proteolysis of titin, nebulin, desmin, and troponin-T were determined on muscle samples from the LD, SM, and PM at early times postmortem. Myofibrils from each muscle were purified to assess myofibril-bound (mu-calpain. Percentage drip loss was determined, and Warner-Bratzler shear (WBS) force was analyzed. Myosin heavy-chain (MHC) isoforms were examined using SDS-PAGE. The pH of PM was lower (P < 0.01) than the pH of LD and SM at 30 and 45 min and 1 h postmortem. The PM had a higher (P < 0.01) percentage of the MHC type IIa/IIx isoforms than the LD. The-LD had the greatest proportion of (P < 0.01) MHC IIb isoforms of any of the muscles. The PM had the lowest (P < 0.01) percentage of MHC IIb isoforms and a greater (P < 0.05) percentage of type I MHC isoforms than the LD and SM. The PM had less (P < 0.01) drip loss after 96 h of storage than the SM and LD. The PM had more desmin degradation (P < 0.01) than the LD and SM at 45 min and 6 h postmortem. Degradation of titin occurred earlier in the PM than the LD and SM. At 45 min postmortem, the PM consistently had some autolysis of mu-calpain, whereas the LD and SM did not. At 6 h postmortem, some autolysis of mu-calpain (80-kDa subunit) was observed in all three muscles. The rapid pH decline and increased rate of autolysis in the PM paralleled an earlier appearance of myofibril-bound mu-calpain. The SM had higher calpastatin activity (P < 0.05) at 45 min, 6 h, and 24 h and had higher WBS values at 48 h (P < 0.01) and 120 h (P < 0.05) postmortem than the LD. At 48 and 120 h postmortem, more degradation of desmin, titin, and nebulin were observed in the LD than in the SM. These results show that mu-calpain activity, mu-calpain autolysis, and protein degradation are associated with differences in pork tenderness and water-holding capacity observed in different muscles.     

Protein and lipid sources affect cholesterol concentrations of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone)

Two experiments were conducted to evaluate the effects of protein and lipid sources on cholesterol, AA, and fatty acid content, and on biological performance of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone). In Exp. 1, seven isonitrogenous and isocaloric diets were prepared using fish meal; soybean meal; casein; fish meal + soybean meal; fish meal + casein; soybean meal + casein; and fish meal + soybean meal + casein. In Exp. 2, seven isonitrogenous and isocaloric diets were prepared using fish oil; soy oil; poultry fat; fish oil + soy oil; fish oil + poultry fat; soy oil + poultry fat; and fish oil + soy oil + poultry fat. Nine shrimp (average BW 570 mg) were stocked per 60-L tank, with three tanks per diet in each experiment. Shrimp were fed to apparent satiation twice daily for 28 d. Protein sources affected shrimp cholesterol, feed consumption, feed efficiency, protein consumption, protein efficiency ratio, and crude body fat (P < or = 0.05), but not weight gain, survival, hepatosomatic index, body protein, ash, and AA composition. Body (without hepatopancreas) cholesterol concentrations were the highest in shrimp fed the diet containing fish meal (0.81%), lowest for those fed the casein diet (0.64%), and intermediate in the other dietary treatment groups (range 0.71 to 0.74%). Lipid source also affected shrimp body cholesterol, body fatty acid profiles, and fatty acid profiles in the hepatopancreas (P < or = 0.05), but not growth performance, body protein, fat, ash, and cholesterol concentrations in the hepatopancreas. Shrimp fed the fish oil diet had the highest body cholesterol (0.75%), whereas those fed the soy oil or poultry fat diets were lowest (0.66 and 0.65%, respectively). Results indicate that by replacing fish meal and fish oil with soybean meal and soy oil, shrimp growth performance is not affected, but body cholesterol concentration is reduced.