Abstract
Abstract
To study the regulation and feedback mechanism of cholecystokinin and trypsin in black bream, Megalobrama pellegrini (Tchang, 1930) 60 days after hatching under 15 days short-term fasting and different feeding frequencies within 24 hours during the same period, M. pellegrini (wet weight 183.75 ± 61.16 mg, total length 20.74 ± 4.08 mm) developed in a recirculating aquaculture system were selected as the subject. In the short-term fasting trial, the body weight, trypsin, and CCK of the feeding control group (FCG) were higher than those of the fasting test group (FTG). Trypsin and CCK in FTG reached the lowest value on the ninth day and the CCK content reached the highest value on the 11th day. A negative feedback regulation of CCK and trypsin had not been found in this trial. The degree of damage to intestinal chorionic epithelial cells was higher than that of hepatopancreas, and detachment of epithelial cells and the striatal border was the main damage. In the 24-hour daily rhythm experiment, juvenile fish were randomly assigned to (A) once feeding, (B) twice feeding, (C) three times feeding, (D) fasting. CCK showed a minimum value at 1:00+ in group A, while a peak occurred at night in group B\C\D and a maximum value in group C, and a single satiety stimulus can lead to increased hunger. The four treatment groups had an apparent closed-loop regulation while the control point of the fasting group (D) shifted forward to the next day. Different feeding frequencies in a single day had no direct effect on the long-term fluctuation of CCK and trypsin diurnal rhythm. Feeding three times a day was beneficial to the individual growth of juvenile M. pellegrini, a better growth results may be produced in the long term. This study aimed to provide a reference for the feeding strategy of juvenile M. pellegrini in the RAS.
Publisher
Research Square Platform LLC
Reference38 articles.
1. Cholecystokinin bioactivity in human plasma. Molecular forms, responses to feeding, and relationship to gallbladder contraction;A LR;J Clin Investig,1985
2. Distribution of cholecystokinin-immunoreactive cells in the gut of developing Atlantic cod Gadus morhua L. larvae fed zooplankton or rotifers;B HM;J Fish Biol,2009
3. Cui W (2013) Cloning and expression characteristics of three gastrointestinal peptide genes in large yellow croaker. Zhejiang Ocean University
4. Galaviz MA, García-Gasca A, Drawbridge M, Álvarez-González CA, López LM (2011) Ontogeny of the digestive tract and enzymatic activity in white seabass, Atractoscion nobilis, larvae. Aquaculture 318(1). https://doi.org/10.1016/j.aquaculture.2011.05.014
5. Gong Y, Luo Z, Zhu Q-L, Zheng J-L, Tan X-Y, Chen Q-L, Lin Y-C, Lu R-H (2013) Characterization and tissue distribution of leptin, leptin receptor and leptin receptor overlapping transcript genes in yellow catfish Pelteobagrus fulvidraco. General and Comparative Endocrinology 182. https://doi.org/https://doi.org/10.1016/j.ygcen.2012.11.006