Observation of the middle intestinal tight junction structure, cloning and studying tissue distribution of the four Claudin genes of the grass carp (Ctenopharyngodon idellus).

To confirm the existence of the tight junction (TJ) in middle intestine and obtain the genetic information of Claudin-3, Claudin-15a, Claudinb and Claudinc of grass carp, we observed the physical structure of TJ by transmission electron microscopy and cloned the partial cDNAs of the four Claudins using reverse transcriptase PCR technique. The four partial cDNAs consist of 1,261, 490, 776 and 662 bp encoded 131, 150, 195 and 171 amino acids, respectively. Homology analysis showed that the grass carp Claudin shared high homology with other teleost species, especially with Danio rerio and Carassius auratus.

Oxygen consumption and ammonia excretion of black carp (Mylopharyngdon piceus Richardson) and allogynogenetic crucian carp (Carassius auratus gibelio female x Cyprinus carpio male) fed different carbohydrate diets.

Oxygen consumption and ammonia excretion of black carp (Mylopharyngdon piceus Richardson) (4.6±0.3 g) and allogynogenetic crucian carp (Carassius auratus gibelio ♀×Cyprinus carpio ♂) (5.