The histopathologic effects of feeding heat-treated soybean meal to fingerling channel catfish (Ictalurus punctatus) were studied. Fish were fed one of six diets: a diet containing 450 g kg−1 commercial soybean meal (CSBM), or diets with the CSBM replaced by non-heat-treated raw soybean meal (RSBM0), or RSBM heated at 130 °C for 5 min (RSBM5), 10 min (RSBM10), 20 min (RSBM20) or 40 min (RSBM40). After 10 weeks, tissue samples were taken from the stomach, proximal intestine, distal intestine, liver, pancreas and spleen from fish in each group for histologic examination. Mild necrotic lesions were found in the gastric glands, pancreas and liver of fish in all the groups (treatment and control groups). Hepatic glycogen deposition was also observed in all the groups, and the spleen samples exhibited considerable brownish-black pigment deposition around the splenic corpuscles and diffuse mild-to-moderate congestion in all of the groups. Generally, these histologic effects appeared to be equivocal between all of the groups, and no abnormalities were noted in the proximal or distal intestine. These findings suggest that feeding channel catfish a diet containing 450 g kg−1 non-heat-treated RSBM did not cause severe histologic changes associated with soybean meal anti-nutritional factors as have been reported in salmonids.
Fish blood agar (FBA) was made using blood from Nile tilapia, Oreochromis niloticus. Four piscine bacterial isolates, Streptococcus iniae, Acinetobacter calcoaceticus, Staphylococcus epidermidis, and Edwardsiella tarda, were chosen according to their different Gram stain, morphologic, and haemolytic characteristics. The isolates were plated on FBA and sheep blood agar (SBA) to compare relative growth according to agar used. Bacteria counts and colony morphology were not significantly different between the same isolates cultured on FBA or SBA. When comparing zones of haemolysis, only the S. iniae zones of haemolysis were significantly smaller on FBA than on the SBA. The results of this study showed that FBA did not have any bacteriological benefits over SBA. Moreover, SBA is easily obtained commercially and may be relatively inexpensive given the labour required for the husbandry of healthy fish, harvest of fish blood, and production of sterile FBA plates. However, FBA may be a suitable alternative to SBA when SBA is not readily available.
SUMMARY Polymorphonuclear neutrophils ( pmn ) from goats fed selenium-deficient and selenium-adequate diets were tested for their ability to perform (i) random migration under agarose, (ii) leukotaxis toward serum chemotaxins under agarose, and (iii) phagocytosis of opsonized zymosan by chemiluminescence analysis, Function of pmn from goats fed the selenium-deficient diet was severely depressed, and incubation of these cells with selenium resulted in marked functional enhancement. Also, administration of selenium to goats fed the selenium-deficient diet resulted in increased pmn functions. Increase or decrease in pmn function was associated with corresponding alterations in blood, serum, and intracytoplasmic pmn glutathione peroxidase activities. It was concluded that a selenium-inadequate diet fed to goats results in depressed pmn function which is associated with physiologic changes in glutathione peroxidase levels.
