An ultrastructural study of the Hepatopancreas of Indian white prawn Penaeus indicus H. Milne Edwards

Electron microscopic studies of the hepatopancrcatic tubule revealed four distinct cell type . The Embryonic cells were undifferentiated with a large nucleus and cytoplasm surrounding it. Golgi complex and free ribosomes wcre abundant. Fibrillar (F-cells) contained extensive rough endoplasmic reticulum with ribosome - studded cisternae. The golgi cisternae were always dilated with numerous zymogen grnnules. Secretory (B-cel1s) showed many vesicles and a large vacuol

Studies on the digestive enzymes of the indian white prawn Penaeus indicus H Milne Edwards

Studies on the digestive enzymes of the indian white prawn Penaeus indicu

Digestive physiology

The efficacy of a feed in promoting maximum growth in shrimps depends not only on its nutritive profile, but also on the animals inherent ability to consume, digest, absorb and metabolise the nutrients which the feed contains. Thus, an understanding of the digestive system and its digestive enzyme complement is extremely important in diet formulation, especially in balancing nutrients and to impose restrictions on use of those nutrients and additives, which may inhibit or alter the digestive processes, and advise optimal use of those nutrients and additives which would assist in achieving improved digestive efficienc

Effect of dietary starch levels on digestive enzyme activity in Penaeus indicus

Purified diets containing graded levels of starch ranging from 0 to40% were prepared and fed to the juveniles of Penaeus indicrrs for a period of 4 weeks. The relative activities of amylases, proteases and lipases were measured in the hepatopancreatic extract. Activity of a-amylase increased with the level of starch in the diet and the maximum substrate turnover of 43.97m rnol Imaltoselmllmin was observed at 20% starch in the diet. However, proteases and lipases did not show any significant variations in their activity patterns. Theeffect of diets on mean live weight gain, digestibility coefficient and survival of prawns were also evaluated. The d.c. value for carbohydrate was the highest (81%) for 20% starch diet. Diets with starch level between 10% and 30% also provided better growth and survival than the other diets. Hence suggest that juveniles of P. indicrrs can digest dietary starch upto a level of 20% and higher level results in lowered d.c.value

Studies on the digestive enzymes of the Indian white prawn Penaeus indicus H. Milne Edwards

The efficiency of a diet not only depends on its nutrient composition and nutrient balance but also on the effective utilization by the animal. In the utilization of dietary nutrients, the digestive enzymes play the crucial role of catalysing the hydrolytic reactions, splitting the macromolecules into simple absorbable molecules. The activity of these biocatalysts is regulated by alterations in pH, temperature, substrate type and concentrations, and also by the presence of activators and inhibitors. Thus any shift from the optimum conditions necessary for these enzymes may affect their activity, thereby correspondingly modify the digestibility of the nutrients supplied to the animals. Thus, investigations on the important digestive enzymes and their preferential conditions of activity are essential, so that the results obtained could be used in rationally adjusting the quality and quantity of feed supplied to the different stages of prawns In India, directed research on nutritional physiology and biochemical approaches to digestion in commercially important prawns is taken up_ only recently, and the field is still in an infant stage. In view of its emerging importance it is identified as an area of priority and the present investigation has been carried out on the Indian white prawn Penaeus indicusCochin University Of Science And TechnologyCentre Of Advanced Studies In Mariculture,Cochin University Of Science And Technolog