1. Laying birds were allowed free access to a basal diet (treatment 1) or were restricted to either early morning and late afternoon access to the basal diet (treatment 2) or a high‐energy diet in the morning and a high‐protein, high‐calcium diet in the afternoon (treatment 3). The sum of the components fed in treatment 3 was equivalent to the basal diet. These diets were fed for 5 weeks. In the next phase of the experiment, which lasted for 3 weeks, the compositions of the diets for treatments 2 and 3 were altered so that the intakes of dietary components approached those of birds on treatment 1.
2. In both experimental phases birds on treatment 3 produced significantly fewer eggs of smaller mean weight and shell weight. Plasma calcium, inorganic phosphorus concentrations and alkaline phosphatase activity were indicative of decreased calcium status. 相似文献
1. Immature birds treated for 7 d with corticotrophin (30 IU/kg, one injection per day) had significantly poorer growth rates and decreased adrenal cholesterol concentrations. Plasma glucose, corticosterone and cholesterol concentrations and adrenal weight were within the normal range 24 h after the last injection.
2. The responses of birds pretreated as described above to a single injection of corticotrophin (30 IU/kg) were determined.
3. A similar degree of hyperglycaemia had developed in both groups after 2 h but thereafter the responses differed: the concentration of plasma glucose did not increase further in those pretreated with corticotrophin and had begun to decrease at 6 h, whereas that of the birds pretreated with saline increased progressively.
4. The concentrations of plasma corticosterone had increased similarly in the two groups to a peak at 2 h but there was a significantly more rapid decrease in the birds pretreated with corticotrophin.
5. Both groups showed a transient hypercholesteraemia but the increase was significant only in the group that had previously received saline.
6. There were decreases in the concentrations of adrenal cholesterol in both groups. The decrease, in absolute terms, was 2–4 times greater in the group receiving corticotrophin for the first time: percentage changes were similar, however. 相似文献
A 10-month-old male domestic short-haired cat was examined because of progressive lameness, a broad face with depressed nasal bridge, small ears, corneal clouding, and multiple bone dysplasia. The cat excreted excessive amounts of glycosaminoglycan (a component of connective tissue) in its urine and had evidence of lysosomal storage of glycosaminoglycans in fibroblasts and neurons. Activity of alpha-L-iduronidase, a lysosomal enzyme involved in glycosaminoglycan degradation, was deficient in cultured fibroblasts and leukocytes. The mucopolysaccharidosis was distinct from that seen in Siamese cats in terms of the pathologic changes and the specific enzyme deficiency. 相似文献
Rotavirus is a name given to a group of viruses that have similar characteristics and are generally capable of causing diarrhea in the young. Infection of pigs with porcine rotavirus is common and widespread and can result in diarrhea, especially in 1- to 4-week-old pigs. This virus is frequently associated with a diarrheal syndrome popularity known as "white scours," "milk scours," or "3-week-old scours." Pigs less than 1 week old are infrequently infected, presumably because of adequate passive immunity. The infection resembles enzootic transmissible gastroenteritis. Diagnosis can be made by immunofluorescent staining of mucosal scrappings from the small intestines. 相似文献
This serologic study was done to gain information on the spread, maintenance, and effect upon performance of five porcine viruses. Blood samples were taken from two groups of 8- to 11-week-old pigs from a large number of Indiana swine herds in a performance-testing station 1 week after entry, 7 weeks after entry (one group only), and at slaughter. The sera were tested by indirect fluorescent antibody tests for antibodies to transmissible gastroenteritis virus (TGEV), swine influenza virus (SIV), hemagglutinating encephalomyelitis virus (HEV), porcine adenovirus (PAV), and pseudorabies virus (PRV). Seroconversions to TGEV, HEV, and PAV occurred in a group of pigs entered in May and slaughtered in August (group 1). In the group that was entered in October and slaughtered in January (group 2), pigs developed antibodies to SIV, HEV, and PAV, but not to TGEV. Only 1 of the 434 pigs tested had antibodies to PRV, and there were no seroconversions to this virus. The only statistically valid effect of infection on performance was found in group 1 pigs, which had seroconverted to TGEV during the first 7 weeks of their stay. These pigs gained 0.077 kg less per day than pigs that did not develop antibodies to TGEV during that period. The pattern of serologic reactions was indicative of a relatively slow spread of these viruses in the groups. We interpret this as supporting the concept that a relatively slow spread of these viruses through large groups of pigs kept under conditions that are less than optimum for virus spread may be an important means of their interepizootic survival. 相似文献
Experimental infection of eastern cottontail rabbits (Sylvilagus floridanus) with infectious bovine rhinotracheitis virus caused acute keratoconjunctivitis and a fatal systemic infection. The clinical syndrome was characterized initially by blepharospasm and ocular discharge. The rabbits were markedly depressed on post-exposure day (PED) 5 and were dead or moribund on PED 6. The virus was readily recovered from liver and adrenal gland tissue on PED 6 and from conjunctival swabs on PED 1 to 6. Histopathologic studies revealed a few necrotic foci in the liver and multiple focal to diffuse necrosis of the adrenal glands. Viral isolation and immunofluorescence tests were used to demonstrate a direct association between infectious bovine rhinotracheitis viral antigens and the lesions. 相似文献
Pulmonic and peripheral blood lymphocyte subpopulations in healthy and Mycoplasma suipneumoniae-infected pigs were compared. The T- and the B-lymphocyte populations were counted, the B cells by the complement receptor (zymosan-complement rosettes) technique and the T cells by the ED-rosette technique (sheep RBC-dextran rosettes). The T cells were found to predominate among pulmonic, as well as blood, lymphocytes. Pulmonic B-cell and blood T-cell percentages were increased after mycoplasma respiratory tract infection. However, blood B-cell and pulmonic T-cell percentages were not significantly affected. A significant (P less than 0.001) correlation between pulmonic and blood T-lymphocyte compositions was found; conversely, no correlation was observed between blood and pulmonic B-cell percentages. These data could imply that pulmonic B cells are predominantly involved in local immune reactions after a mycoplasma respiratory tract infection. 相似文献