Changes in digestive enzyme activities during the early ontogeny of milkfish, Chanos chanos larvae

• Published in: Fish physiology and biochemistry 2023-10, Vol.49 (5), p.867-882
• Main Authors: Sivaramakrishnan, Thirugnanamurthy, Ambasankar, Kondusamy, Felix, Nathan, Bera, Aritra, Kamalam, Biju Sam, Vasagam, K.P. Kumaraguru, Kailasam, Muniyandi
• Format: Article
• Language: English
• Subjects: Alkaline phosphatase; Aminopeptidase; Amylases; Animal Anatomy; Animal Biochemistry; Animal Physiology; Aquaculture; Aquatic crustaceans; Artemia; Artemia salina; Biomedical and Life Sciences; Brachionus plicatilis; Brackish water; Brackishwater aquaculture; Breeding; carboxylic ester hydrolases; Chanos chanos; Chlorella; Chymotrypsin; digestion; Digestive enzymes; Digestive system; Enzymatic activity; Enzyme activity; Enzymes; Fish; Fish hatcheries; Fish larvae; Freshwater & Marine Ecology; Growth curves; Hatcheries; Hatching; Histology; India; intestines; Larvae; Larval stage; Length-weight relationships; Leucine; leucyl aminopeptidase; Life Sciences; Lipase; Marine fish; Marine fishes; Marine invertebrates; microvilli; Morphology; Nauplii; Nutritional requirements; Ontogeny; Pancreas; Phosphatase; Polyculture (aquaculture); Trypsin; Weaning; Zoology
• ISSN: 0920-1742; 1573-5168
• DOI: 10.1007/s10695-023-01225-1

Knowledge of the developmental ontogeny of the digestive system and nutritional requirements of marine fish larvae is a primary requisite for their successful rearing under an optimal feeding regime. In this context, we assessed the activity profile of key digestive enzymes viz., trypsin, chymotrypsin, leucine aminopeptidase, lipase, amylase, and alkaline phosphatase during the early ontogeny of milkfish, Chanos chanos (0 day, 3 days, 6 days, 9 days, 12 days, 15 days, 18 days, 21 days, 25 days, and 30 days post-hatch). Larvae for this study were obtained from the successful breeding of milkfish at ICAR-Central Institute of Brackishwater Aquaculture, India. Growth curves (length and weight) of the larvae indicated a positive morphological development under a standardized feeding regime that comprised Chlorella salina , Brachionus plicatilis , Artemia salina nauplii, and commercial weaning feed for different larval stages. With respect to protein digestion, the specific activity of pancreatic enzymes trypsin and chymotrypsin and intestinal brush border leucine aminopeptidase showed two peaks at 3 dph and 15 dph, following the introduction of rotifer and Artemia nauplii . Similar bimodal peaks were observed for alkaline phosphatase and amylase activities, with the first peak at 3 dph and the second peak at 18 dph and 21 dph, respectively. Whereas in the case of lipase, high activity levels were observed at 0 dph, 3 dph, and 18 dph, with subsequent decreases and fluctuations. Overall, as most of the enzymes were found to have peak activities at 15 to 21 dph, this period can be potentially considered as the developmental window for weaning larvae from live to formulated feeds in milkfish hatcheries.