RESUMEN
Anatomical and physiological properties of the digestive tract were examined and compared in young rabbits nursed either by one (SS) or by two does (DD) daily up to the age of 35 days. At the age of 23, 30, 37 and 44 days, 8 young per treatment were euthanised. Double suckling and the subsequent higher level of solid feed intake after weaning were found to exert a stronger influence on the weight of the entire gastrointestinal tract and that of its individual parts (the stomach, small intestine, caecum and colon) than on its length. The quantity of the gastric content was found to rise with advancing age in both groups (from 36 to 70 g and from 37.5 to 79 g). In both groups the pH of the stomach was higher during the suckling period (4.5-5.3) than subsequent to weaning (1.6-2.4). The quantity of the caecal content also increased with age (from 4 or 8 g), but on the 37th day significantly higher quantities of caecal content were recorded in DD rabbits (50.5 g compared with 35 g). The pH of the caecal content decreased more slowly from an initial high value (6.0 and 6.5 in SS and DD rabbits, respectively), and by the 37th day had settled at a low value (5.7-5.8) in both groups. The dry matter content of the caecal content decreased from 270-273 g to 188-207 g in both groups. Total volatile fatty acid (tVFA) and acetic acid (C2) concentration, which amounted to 66-88% of tVFA, rose; in SS rabbits they were at higher levels by the 30th day (53.6 and 42.2 mmol/L, respectively), and remained at an increased level until the 44th day (P < 0.05). The ratio of C3: C4 was high on the 23rd day (2.5 and 2.4), but dropped at the age of 30 days (0.5 in SS and 1.7 in DD, P < 0.05) and, further, by the 37th day (0.2 in SS). In SS rabbits coliform count proved significantly lower (10(5)) on the 23rd day than in DD rabbits (10(6)). By the 37th day this count had decreased in both groups and subsequently remained at a low level (< 10(4)). By the 23rd day Bacteroides were present in large quantities (10(8)) in the caecum and showed no change with advancing age or feeding regime.
Asunto(s)
Envejecimiento/fisiología , Animales Lactantes/anatomía & histología , Animales Lactantes/fisiología , Sistema Digestivo/anatomía & histología , Conejos/anatomía & histología , Conejos/fisiología , Animales , Peso Corporal , Sistema Digestivo/química , Sistema Digestivo/microbiología , Ácidos Grasos Volátiles/análisis , Femenino , Contenido Digestivo , Concentración de Iones de Hidrógeno , Masculino , Leche , Tamaño de los ÓrganosRESUMEN
Ochratoxin A (OTA) is a nephrotoxic and carcinogenic mycotoxin, a secondary metabolite produced by mould fungi belonging to several Aspergillus and Penicillium species. It is formed during the storage of cereal grains and other plant-derived products. OTA ingested by humans and animals with the food or feed may exert deleterious effects on health. The purpose of this study was to investigate the ochratoxin contamination of the most important potential sources of OTA. The OTA content of cereal samples for human consumption (36 baking wheat, 16 wheat flour and 6 maize coarse meal samples) and feed grain samples (30 feeding wheat, 32 feeding maize and 20 feeding barley samples) collected in the mid-phase or at the end of the storage period and of 50 commercial coffee samples was determined. The analyses were performed by immunoaffinity column--high-performance liquid chromatography (IAC-HPLC). The limit of detection of the method was 0.1 ng/g. Of the wheat samples intended for human consumption, 8.3% contained OTA at 0.29 ng/g on the average (OTA ranges: 0.12-0.5 ng/g; Table 2). The OTA contamination of wheat flour and maize meal samples for human consumption was similar to that of the baking wheat samples. OTA contamination was found in 26.7% of the feeding wheat, 15.6% of the feeding maize and 35% of the feeding barley samples. The average values and the ranges of OTA levels found in the above samples were 12.2 and 0.3-62.8 ng/g, 4.9 and 1.9-8.3 ng/g, and 72 and 0.14-212 ng/g, respectively (Table 3). Sixty-six percent of the coffee samples were contaminated with OA (average level: 0.57 ng/g, ranges: 0.17-1.3 ng/g; Table 4). OTA contamination of baking wheat samples was found to be relatively low, presumably as a result of the favourable weather at harvest and the optimal storage conditions. Calculations made on the basis of the obtained results show that the daily OTA intake of an adult human from edible cereals is only 6.7 ng, while the amount taken up with coffee is 4.1 ng daily. The high prevalence and high levels of OTA contamination in feed grains can be explained by the unfavourable storage conditions, and this finding suggests that OA-related health problems may arise in animals, and that foods of animal origin may be contaminated with this mycotoxin.