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171.
M. A. Gomez J. A. Navarro S. Gomez P. Camara J. C. Gomez A. Bernabé 《Anatomia, histologia, embryologia》1989,18(4):305-315
The structure and ultrastructure of the adenohypophyseal pars distalis in kids of the Murciano-granadiana breed (18 males and 12 females), aged 2-3 months and with an average carcass weight of 8 kg has been studied. Techniques of staining (Tetrachrome Herlant's, and Cleveland-Wolfe) and histochemistry (PAS, PAS-OG and BA-PAS-OG) contrasted with immunolabelling (PAP) have been used. In addition an ultrastructural study has been made and nucleus and cytoplasm, secretory granules, mitochondria and lysosomes have been measured with a semiautomatic image analyzer (IBAS-1). TSH cells are found in sagittal section in the anterior area and in an antero-caudodorsal band, and transversally in the ventral and medial region; they are 6% and their average size is 14.15 microns. Ultrastructurally they are a single cellular type with spherical granules whose size is 195 nm in males and 149 in females; these granules are characterized by a clear halo and a variable electronic density. The rough endoplasmic reticulum is found as slightly enlarged vesicles with a homogeneous and moderately electro-dense content or in concentric stratifications. 相似文献
172.
N E Forsberg M A Ilian A Ali-Bar P R Cheeke N B Wehr 《Journal of animal science》1989,67(12):3313-3321
The objectives of this study were to examine effects of a beta-adrenergic agonist (cimaterol) on growth and muscle development in rabbits and to examine cimaterol's effects on myofibrillar protein degradation (MPD) and on activities of several proteolytic enzymes including the calcium-dependent proteinases (CDP). Twelve New Zealand White rabbits were assigned to either control diets or to diets containing cimaterol for 35 d, after which they were killed and effects on performance and tissue weight gains were determined. Urine was collected from d 21 through 28 from each rabbit for assessment of N tau-methylhistidine (NMH) excretion. Cimaterol increased rates of gain, efficiency of gain and skeletal muscle weights. Enhancement in muscle weight was associated with an increase in total DNA and with a reduction in NMH. Cimaterol did not affect activities of cathepsin B, cathepsin D or neutral serine proteinase, but it reduced activities of the millimolar and micromolar forms of the CDP by 58 and 57%, respectively, and it reduced activity of the inhibitor of the CDP (calpastatin) by 52%. Cimaterol-dependent myofibrillar protein accretion was likely mediated, at least in part, by a reduction in MPD. The change in MPD was associated with a reduction in muscle CDP activities. Cimaterol-dependent muscle hypertrophy therefore may involve changes in calcium-dependent proteolysis of myofibrillar proteins. The significance of the effects of cimaterol on calpastatin activity is not known. 相似文献
173.
174.
Three strip test kits which measure calcium and/or magnesium in mares' mammary secretions were compared and assessed for their accuracy in:- 1) measuring these electrolytes compared to standard laboratory measurements, and 2) predicting the time of parturition. Daily samples of mammary secretions were obtained pre-partum from 35 Thoroughbred mares and allocated a score. Measurement of mammary secretion calcium and/or magnesium by the strip tests and laboratory methods correlated significantly (P less than 0.001). The results obtained for prediction of parturition were analysed by two methods. Method i) indicated that the majority of mares had a maximum score on the day of birth. However, the second method of analysis included all prepartum scores and this demonstrated that maximum scores occurred on more occasions prior to the day of birth than on the day of birth itself. The number of nights spent attending mares, and the percentage of occasions when foaling was missed, were also calculated for given strip test scores. The results indicate that the test kits are not particularly accurate in predicting time of parturition although they are a reliable means of measuring mammary secretion calcium and/or magnesium. It is suggested that the test kits may be more helpful by indicating when it is not necessary to attend mares at night. 相似文献
175.
Epidemiological studies of piglet diarrhoea in intensively managed Danish sow herds. II. Post-weaning diarrhoea 总被引:1,自引:0,他引:1
This study comprised 48,931 litters in 89 sow herds. During the study (1976-82) weaning age decreased from approx. 42 days to approx. 30 days. The mean incidence of post-weaning diarrhoea was 6.0% of litters weaned, with little variation by year but with considerable variation among herds. Within the individual herd increased incidence occurred over limited periods, probably associated with specific infections. Litters with diarrhoea during the suckling period had increased risk of post-weaning diarrhoea. The incidence of post-weaning diarrhoea increased with litter size at weaning. Thus, a litter of 11-12 piglets at weaning had 1.2 times higher risk than litters with 8-10 piglets. In contrast to pre-weaning diarrhoea, there was no association between parity of the sow and diarrhoea in the litter after weaning. Litters weaned below 2 weeks of age had a 2-fold risk of developing diarrhoea after weaning and a 2.4-fold higher mortality rate than did litters weaned at 6-7 weeks. Similarly, litters weaned at an individual piglet weight below 3 kg bodyweight had a 3-fold higher risk of developing diarrhoea after weaning and a 5-fold higher mortality rate than did pigs from litters weaned at a bodyweight of 7-8 kg. The incidence of post-weaning diarrhoea decreased with increasing herd size. Piglets from litters with post-weaning diarrhoea had reduced weight gains after weaning and were 2.3 days older at 25 kg bodyweight than piglets from non-diarrhoeic litters. Likewise, diarrhoea after weaning was associated with an increased incidence of diseases of the skin and respiratory tract. Thus the risk of contracting respiratory disease was 4 times greater in diarrhoeic litters. 相似文献
176.
The ultrastructure of sarcocysts of macro- and microscopic species of Sarcocystis was compared from naturally infected water buffalo from India. Grossly visible sarcocysts had walls consisting of cauliflower-like villar protrusions, typical of S. fusiformis. The sarcocyst wall of the microscopic species of Sarcocystis was 6.4 microns thick and consisted of tightly packed conical villar protrusions that were 9.6 microns long and 3.7 microns wide at the base. At approximately 3 microns above the base, the distal two-thirds of the villar protrusion became conical shaped and was bent laterally at an angle of 45 degrees to the sarcocyst surface. The granular layer beneath the villar protrusions was 0.9 microns thick. In S. levinei the granular layer was 1.9 microns thick, the villar protrusions were narrow and it had a highly undulating primary cyst wall. Whether the microscopic S. levinei-like sarcocysts of Indian and Malaysian water buffalo are distinct species of Sarcocystis will require further investigation. 相似文献
177.
Calcium fluxes were measured, in vivo, in both directions across the ovine reticulorumen wall of four sheep when the luminal potassium concentration was either 30 mmol litre-1 or 90 mmol litre-1. Neither fluxes were affected by an increased potassium concentration although net magnesium absorption was decreased (PO less than 0.05) and the transmural potential difference was increased (P less than 0.01) under these conditions. The results obtained suggest that, unlike magnesium, calcium is transported bidirectionally across ovine ruminal tissue independently of the transmural potential difference across the rumen wall. 相似文献
178.
179.
M Contrepois H C Dubourguier A L Parodi J P Girardeau J L Ollier 《Veterinary microbiology》1986,12(2):109-118
Three strains of Escherichia coli with a common surface antigen, 31a, capable of adhering to calf enterocytes in vitro were compared to reference strains of septicaemic E. coli (RVC 330 and vir E. coli). The surface antigen 31a was present in the RVC 330 reference strain. E. coli vir had a surface antigen which was not present in E. coli 31a or E. coli RVC 330. The RVC 330 and vir reference strains also adhered to calf enterocytes in vitro. Oral infection of calves not receiving colostrum with E. coli 31a was generally followed by septicaemia and death in less than 48 h. Post-mortem examination revealed pneumonia and oedema of the kidneys and gall bladder. Oral infection of calves receiving colostrum had no effect, but intravenous inoculation produced arthritis within 15 days. The comparison of these results with those previously described by other workers did not lead to the identification of pathognomonic characteristics, which could be clearly correlated with properties specific to E. coli 31a. It is suggested that, like ColV and vir, antigen 31a may be a virulence marker for certain strains of bovine septicaemic E. coli. Furthermore, the 31a antigen appears to be carried on a plasmid. 相似文献
180.