Oreochromis Aureus (Oreochromi + aureu)

Distribution by Scientific Domains


Selected Abstracts


Effects of non-starch polysaccharides enzyme, phytase and citric acid on activities of endogenous digestive enzymes of tilapia (Oreochromis niloticus Oreochromis aureus)

AQUACULTURE NUTRITION, Issue 4 2009
J.S. LI
Abstract Non-starch polysaccharides (NSPs) enzyme, phytase and citric acid have been shown to increase digestibility in pigs, poultry and some fish. To examine their roles in digestion in tilapia (Oreochromis niloticus Oreochromis aureus), the present study was designed to evaluate their effects on activities of a number of endogenous digestive enzymes in tilapia. Neither NSPs enzyme (1 g kg,1) nor phytase (1 g kg,1) affected the activities of protease in digestive organs. In contrast, NSPs enzyme increased the activities of amylase in the hepatopancreas and intestine by 11.4% and 49.5%, respectively, while phytase (1 g kg,1) increased the activities of amylase in the hepatopancreas and intestine by 14.0% and 24.1%, respectively. Citric acid (10 g kg,1) increased the activities of protease in stomach by 29.6%, but reduced the activities of protease in the intestine by 35.1%. Citric acid increased the activities of amylase in the hepatopancreas and intestine by 30.7% and 29.4%. Lipase activities were not affected by NSPs enzyme, phytase or citric acid. Above results suggest that NSPs enzyme, phytase and citric acid primarily influence the activities of amylase in digestive tract of tilapia. [source]


Effect of incubation temperature on carbohydrate digestion in important teleosts for aquaculture

AQUACULTURE RESEARCH, Issue 13 2005
Eustratios S Papoutsoglou
Abstract The activity and capacity (activity tissue weight) of digestive carbohydrases (total carbohydrase, ,-glucosidase, ,-amylase) was examined in vitro under a range of (more realistic) incubation temperatures (5, 18 and 25C) and pH (7.6) more likely to be encountered during rearing, along the digestive tract of important teleost species for aquaculture (Dicentrarchus labrax, Sparus aurata, Oreochromis aureus, Oncorhynchus mykiss and Salmo salar). Results indicate, among other things, an overestimation of digestive carbohydrase levels when performing assays at 37C, a different effect of temperature on digestive enzyme performance along the digestive tract of examined species, and the increased importance of ,-glucosidase towards carbohydrate digestion. Implications regarding the capacity of each species for carbohydrate digestion in nature, as well as feed manufacturing, are discussed. [source]


Incidence of conjoined twins in tilapia after thermal shock induction of polyploidy

AQUACULTURE RESEARCH, Issue 5 2000
M Owusu-Frimpong
Conjoined twins (polyembryonic fish) were observed in batches of blue tilapia Oreochromis aureus (Steindachner) and Nile tilapia O. niloticus (L.) embryos incubated at 28 C. Heat shock (41.8 C) treatment of fertilized eggs for 3,4 min applied between 4 min and 27 min after fertilization increased the twinning rate by three or four times over that of unshocked eggs. Two basic morphological variations , ventrally or laterally conjoined twins , were observed. Twins did not survive beyond 21 days after hatching. The proportion of twins in heat-shocked egg batches of both species combined ranged from 0.32% to 0.40%. [source]