The ultrastructure of the intestinal epithelium in Oreochromis niloticus on a diet with different concentrations of zinc.

The effects of diets with variable zinc levels on the midgut epithelial cells were studied in Oreochromis niloticus L. One hundred and twenty fry of tilapia were apportioned into 4 experimental groups (I, II, III and IV groups), with 30 fish in each treatment, 5 replicate aquaria per treatment containing 6 fish each. The animals of the 4 groups were fed with isonitrogenous (30% crude protein) and isoenergetic (3000 Kcal/Kg of digestible energy) diets with increasing quantities of zinc (44.59; 149.17; 309.93; 599.67 mg Zn/kg of diet), twice a day, for 93 days. Three fish from each group were sacrificed at 36, 66 and 93 days and samples of midgut were removed for ultrastructural analysis. After 93 days of treatment, 3 animals of each experimental group were used for the analysis of zinc concentration by atomic absorption spectrophotometry. The comparative relative index (CRI) revealed that the animals in groups II, III and IV contained, respectively, 1.99%, 34.67% and 22.78% more zinc than the mean concentration in animals from group I. The ultrastructural analysis showed enterocytes with swelling of smooth surfaced endoplasmic reticulum and dilated mitochondria with variable matrix rarefaction and cristae number reduction in the fish exposed to 599.67 mg Zn/Kg of diet at 66 and 93 days of treatment.

Effects of Annona squamosa extract on early pregnancy in rats.

Annona squamosa Linn., family Annonaceae, is said to show varied medicinal effects, including insecticide, antiovulatory and abortifacient. The purpose of present study was to investigate if A. squamosa seed aqueous extract, in doses higher than that popularly used to provoke abortion, interferes with reproductive performance, and to correlate the ingestion of this extract with possible alterations in rat embryonic implantation. Doses of 300 mg/kg (Treated Group I, n = 17) and 600 mg/kg (Treated Group II, n = 12) body wt. were administered by gavage, during days 1 to 5 of pregnancy (preimplantation period). The control group (n = 13) received water in the same manner, during the same period for comparison with experimental groups. The animals were euthanized on day 10 of pregnancy. Treatment of dams during the preimplantation period showed no signs of toxicity, and no alteration in the corpora lutea, implantations and embryo in terms of development numbers. The percentage of preimplantation and postimplantation losses in treated groups I and II did not differ from those of control. Treatment with aqueous extract of A. squamosa seeds caused no morphological change in the endometrium. The absence of morphological alterations in uterine epithelial cells in treated groups I and II permitted a viable embryonic implantation, as verified by the number of embryos in development at day 10 of pregnancy. Thus, A. squamosa seed aqueous extract did not interfere with the reproductive performance of pregnant rats.

Histochemical fibre types of the adductor mandibulae muscle in carp: cyprinus carpio, L. 1758

En este trabajo analizamos las características histoquímicas de los segmentos mandibular y maxilar del músculo aductor de la mandíbula en la carga. Las fibras musculares fueron clasificadas en tres tipos, de acuerdo con las distintas reacciones de las enzimas mATPasa (con pre-incubación ácida y alcalina) y NADH-TR. En la zona profunda fueron observadas solamente fibres rojas con metabolismo oxidativo. La zona superficial presentó fibras blancas con metabolismo glicólico. En las zonas de transición y profunda, fueron observadas fibras rojas, pequeñas, con metabolismo intermediario, dispuestas alredededor de fibras más grandes. Las fibras rojas fueron predominantes en el músculo A1 y las blancas en el A1a, ambos pertenecientes al segmento maxilar. En el segmento mandibular, el músculo A2 presentó numerosas fibras blancas dispuestas alrededor de muy pocas fibras rojas, las cuales predominaron en el músculo A3