title: Changes in digestive enzyme activities during larval development of Chinese loach Paramisgurnus dabryanus (Dabry de Thiersant, 1872).
abstract: The digestive physiology of Chinese loach (Paramisgurnus dabryanus) was studied by assessing the specific and total activities of different pancreatic (trypsin, chymotrypsin, amylase and lipase), gastric (pepsin) and intestinal (alkaline phosphatase and leucine-aminopeptidase) enzymes from hatching to 40 days after hatching (DAH). Larvae were reared at 24.4 ± 0.4 °C and fed with rotifers from mouth opening (4 DAH) to 15 DAH, from 10 to 35 DAH with Cladocera and from 30 to 40 DAH with compound diet. Enzyme activities for trypsin, chymotrypsin, amylase and lipase were detected before the onset of exogenous feeding, indicating that these enzymes were genetically pre-programmed. Most of the pancreatic enzyme specific activities increased until 20 DAH and decreased thereafter. The pepsin activity of Chinese loach was firstly detected at 30 DAH, indicating the appearance of functional gastric gland. Alkaline phosphatase specific activity was detected from hatching onward, showed marked increase and reached the second peak at 20 DAH, while a gradual increase in specific leucine-aminopeptidase activity was observed until the end of the experiment. Accordingly, the larvae of Chinese loach possess a functional digestive system before the onset of exogenous feeding and the digestive capacity gradually increases as development progresses. The abrupt increase in intestinal enzyme activities between 10 and 20 DAH demonstrates onset of juvenile-like digestive mode in Chinese loach larvae. The increase in pepsin activity after 30 DAH indicates the shift from alkaline to acidic digestion in Chinese loach larvae, which may be considered as the onset of weaning.
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Yun-Long
authors.initials: YL
authors.lastname: Zhang
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Qiao-Wan
authors.initials: QW
authors.lastname: Wu
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Hu
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Fan
authors.initials: F
authors.lastname: Wang
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Zhong-Bo
authors.initials: ZB
authors.lastname: Zhao
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: He
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Wei-Han
authors.initials: WH
authors.lastname: Shao
authors.affiliation: Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fishery, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China. fanqixue@mail.hzau.edu.cn.
authors.forename: Qi-Xue
authors.initials: QX
authors.lastname: Fan
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000681:Amylases / Q000378:metabolism; D000818:Animals; D002918:Chymotrypsin / Q000378:metabolism; D003531:Cypriniformes / Q000254:growth & development*; D004063:Digestion; D007422:Intestines / Q000201:enzymology*; D007814:Larva / Q000254:growth & development; D007931:Leucyl Aminopeptidase / Q000378:metabolism; D008049:Lipase / Q000378:metabolism; D010179:Pancreas / Q000201:enzymology*; D010434:Pepsin A / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
chemical_list: D008049:Lipase; D000469:Alkaline Phosphatase; D000681:Amylases; D007931:Leucyl Aminopeptidase; D002918:Chymotrypsin; D014357:Trypsin; D010434:Pepsin A
keywords: Digestive enzyme; Larval development; Ontogeny; Paramisgurnus dabryanus