A novel approach to growth promotion using auto-immunisation against somatostatin. I. Effects on growth and hormone levels in lambs

Nine three-week-old lambs were immunised against somatostatin linked to human serum globulin. Significant antibody titres were obtained in all these lambs. The rate of weight gain was greater in those animals immunised against somatostatin (treated) than in the control animals which were immunised against globulin alone (P < 0.001). The final height of the treated lambs was also significantly greater (P < 0.05) as a result of increased height velocity during the period of treatment (P < 0.01).Evaluation of the animals both before and after slaughter indicated that there was no effect of treatment upon body composition, but rather that there had been proportional growth. The carcass assessments revealed that the treated lambs had a longer leg-length (P < 0.01) and had a greater warm carcass weight (P < 0.05) than the control animals, but had similar scores for fat and muscle covering. There was no difference in wool weight between the two groups.No significant difference was found between the groups in the basal levels of either insulin or growth hormone. However, growth hormone release following arginine infusion was greater in the treated animals. There was also a small, but significant, difference (P < 0.05) in the levels of bioassayable somatomedin activity between the treated and control lambs, the treated lambs having higher somatomedin activity.Histological examination of the pancreas from control and treated lambs revealed an increased incidence of abnormalities (mainly acinar necrosis and loss of beta-cell staining) in the islets of Langerhans in the treated lambs, but it could not be concluded that auto-immunisation against somatostatin produced any specific morphological change in the betacells of the pancreatic islets.The results of this study suggest that somatostatin plays an important physiological role in regulating growth stimulation. Removal of the inhibitory effect of somatostatin (in this case by neutralisation of the effect with antibodies) can result in increased growth. The hormonal changes induced by this treatment have yet to be fully elucidated. Further investigations are required to assess the usefulness of this treatment as an alternative to the more conventional synthetic steroid treatments for growth promotion.     

The presence and distribution of beta-galactosidases in the small intestinal mucosa of the neonatal dog.

The beta-galactosidase activity of the small intestinal mucosa of the neonatal dog has been studied over the pH range 3-0 - 5-8 using different substrates and in the presence and absence of p-chloromercuribenzoate. Partial separation of two beta-galactosidases has been achieved by gel filtration. The results suggest that three beta-galactosidases, comparable with those in other mammals, exist in canine small intestinal mucosa.     

Ultrastructural features of Cowdria ruminantium in midgut epithelial cells and salivary glands of nymphal Amblyomma hebraeum

Colonies of Cowdria ruminantium were studied in midgut epithelial cells and salivary gland acini of nymphal Amblyomma hebraeum that were infected experimentally as larvae. Colonies were found in both tissues and studied with light and electron microscopy. Colonies observed within gut cells frequently contained 2 types of the organism: electron-dense and reticulated forms. The morphology of colonies from salivary glands, as seen with light microscopy, varied from compact, densely-staining, small colonies to larger ones in which individual organisms were apparent. With electron microscopy, most organisms in salivary glands were reticulated and appeared to be dividing by binary fission. In both types of host cells, colonies often contained a dense inclusion to which reticulated organisms were adhered.     

Quantitative buffy coat analysis of blood collected from dogs, cats, and horses

Using quantitative buffy coat analysis (QBCA), rapid and accurate measurements can be made of the erythrocyte PCV, total WBC count, and platelet count, and the leukocyte population can be differentiated into total granulocytes (including quantitation of eosinophils), and lymphocytes and monocytes. The QBCA is performed by placing a blood sample (50 to 111 microliters) into a high-precision-bore microhematocrit tube that contains a freely moving, closely fitting, cylindrical plastic float. After centrifugation for 5 minutes, the buffy coat components separate by density. The plastic cylinder floats in the buffy coat, thereby expanding the lengths of the buffy coat layers. The layers are measured in a manner that is similar to that used for measuring PCV. Results of QBCA of blood samples from dogs, cats, and horses indicated that the hematologic values obtained correlated with results obtained by use of conventional methods. The accuracy and ease of use of QBCA and the availability of results while the animal is still being examined make QBCA a useful tool for hematologic evaluation of animals.     

Hemodynamics in the guinea pig after anesthetization with ketamine/xylazine

The resting hemodynamics were determined in 8 guinea pigs after they were anesthetized with ketamine/xylazine. Measurements were made of blood pressure, heart rate, cardiac output, arterial blood gases, and pH. These measurements were obtained initially at 4 to 5 hours after an injection (IM) of ketamine HCl (25 mg) and xylazine (0.15 mg) was given to anesthetize the animals for catheterization (period 1), again 5 days after the operation (period 2), and finally 4 to 5 hours after a 2nd injection of ketamine/xylazine (period 3). There were no differences in heart rates, respiratory rates, or cardiac outputs among the 3 study periods. However, arterial blood pressure was slightly, but significantly, lowered after, and presumably due to, instrumentation (62 +/- 4 mm of Hg, P less than 0.05) when compared with the 5-day postoperative period (67 +/- 7 mm of Hg) or after the readministration of anesthetics (66 +/- 7 mm of Hg). The partial pressure of carbon dioxide in the arterial blood was slightly lower (4 mm of Hg, P less than 0.05) in both acutely postanesthetic periods (period 1 and period 3) than in the same animals at postoperative day 5 (period 2). This study has demonstrated that resting hemodynamics measured shortly after this anesthesia with ketamine/xylazine are not largely different from those in chronically instrumented animals.     

Factors governing the toxicity of putative synaptic transmitters and their analogues when injected into the haemocoel of adult male Lucilia sericata

Acetylocholine, arecoline, 2-(dimethylamino)ethyl acetate, L-glutamic acid, L-4-methyl-eneglutamic acid, (±)-quisqualic acid, 4-aminobutyric acid, and dicrotophos were injected into the haemocoel of adult male Lucilia sericata. Large doses of the putative transmitters and their analogues were required for toxicity. The water soluble organo-phosphate dicrotophos was much more toxic than any of the other compounds. Electrophysiological experiments indicated that the putative transmitters were reaching their presumed site of action in the nervous system and that their toxicity could be correlated with the intensity and duration of their effect at this site. Biochemical measurements of the rate of loss of the putative transmitters from the haemolymph indicate that, in vivo, the test insect possesses efficient mechanisms for removing these compounds from the system being studied. It is concluded that the low toxicity of the putative transmitters, which are presumed to interact reversibly with post synaptic receptor sites, may be largely due to their rapid removal from the system, resulting in a rapid fall in concentration at the receptor site.     

Behavior of sick animals

The behavior of the sick animal is not necessarily a result of physical debilitation; it can be viewed as part of a highly organized adaptive strategy that is at times critical to survival if the animal were living in the wild state. Domestic ruminants appear to have retained this behavioral mode when they are sick. This article brings together several lines of current research about depression, appetite control, and the role of fever in facilitating an animal's ability to combat viral and bacterial infections.