title: Modulation of digestive enzyme activities during ontogeny of Labeo rohita larvae fed ascorbic acid enriched zooplankton.
abstract: The effect of supplementation of ascorbic acid through enriched zooplankton [10%, 20% and 30% ascorbyl palmitate (AP) inclusion in diet of zooplankton] on different digestive enzyme activities during ontogeny of Labeo rohita larvae was studied from 4 day to 15 day post hatch. Ascorbic acid (AA) content in different groups of unenriched (8.6+/-0.71) and enriched zooplankton were, 750+/-29.3, 1409.1+/-45.5, 2009.21+/-199.2 mug/g respectively on dry matter basis with differences (P<0.05) between the treatments. A difference (P<0.05) was found in tissue AA level in different dietary groups. Low amylase, protease, lipase and alkaline phosphatase activities were present in rohu larvae from the mouth opening stage which showed increasing trend with the age of larvae and increasing dietary AA content. A clear dose-dependent modulation of digestive enzyme activities in response to 10%, 20% and 30% AP enriched zooplankton feeding was evidenced from positive correlations between dietary AA content with magnitude of elevation of enzyme activity in different groups. There were 57, 55, 29.2 and 2 fold increases in amylase activity; 7.35, 7.02, 4.43 and 2.73 fold increases in protease activity; 45.636, 41.50, 19.83 and 13.69 fold increases in lipase activity and 6, 5, 3, and 2 fold increases in alkaline phosphatase activity observed in the 15th day post hatch larvae fed 20%, 30%, 10%AP enriched and normal zooplankton respectively, than 4-day post hatch larvae of the respective groups. Enzyme activities were also positively correlated with specific growth rates of wet weight of rohu larvae at the 15th day post hatch. Increased AA might have played an important role in advancing morphological transformation of the digestive tract, protecting gastric mucosa and accelerating growth by the process of tissue formation, which necessitated the requirement of more nutrient thereby, increasing digestive enzyme activity. The regulatory role of AA in the modulation of different digestive enzymes activity and its physiological consequences of nutrient digestibility and utilization during ontogenesis could be extrapolated for better nutrient management of the larvae.
authors.affiliation: Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar-751 002, Orissa, India. gopamitra@yahoo.com
authors.forename: Gopa
authors.initials: G
authors.lastname: Mitra
authors.forename: P K
authors.initials: PK
authors.lastname: Mukhopadhyay
authors.forename: S
authors.initials: S
authors.lastname: Ayyappan
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D000681:Amylases / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000031:analogs & derivatives; D018533:Biomass; D003530:Cyprinidae / Q000254:growth & development / Q000378:metabolism; D004032:Diet; D004063:Digestion / Q000187:drug effects / Q000502:physiology; D004064:Digestive System / Q000187:drug effects* / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D007814:Larva / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D008049:Lipase / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D009024:Morphogenesis / Q000187:drug effects*; D010447:Peptide Hydrolases / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D015048:Zooplankton
chemical_list: D008049:Lipase; D000469:Alkaline Phosphatase; D000681:Amylases; D010447:Peptide Hydrolases; D001205:Ascorbic Acid; C031226:6-O-palmitoylascorbic acid