Abstract:
The feed domestication and feed farming technology of Siniperca chuatsi is one of the key technologies that promote the sustainable development of the
S. chuatsi industry. At present, the time when
S. chuatsi are trained to feed is relatively later than that of common fish. This situation has increased the production cost of
S. chuatsi larvae and restricted the development of the industry. However, there have been no reports on the early docile feeding of
S. chuatsi so far. To investigate the effects of different domestication times on growth, digestion, domestication rate, and immune competence of
S. chuatsi larvae, three experimental groups (D10, D13, and D16) were set up, with three parallel fish in each group and 900 juvenile mandarin fish in each parallel. The three groups began to train and feed on the 10th, 13th, and 16th days after they opened their mouths to eat. The entire experimental period lasted for six weeks. The results showed that the weight gain rate, daily weight gain and specific growth rate of
S. chuatsi larvae in group D16 all reached the highest levels and were significantly higher than those in group D10 (
P < 0.05). Domestication rate in D16 was also significantly higher than in D10, whereas no statistical difference was detected between D16 and D13. Whole-body crude lipid and crude protein contents, together with intestinal trypsin and lipase activities, were significantly elevated in D16 relative to D10. Transcript levels of the digestive genes
try,
alp,
lap3, and anpep in the intestine were likewise up-regulated in D16 compared with D10 (
P < 0.05). Antioxidant capacity was compromised in D10, as evidenced by lower superoxide dismutase (SOD) and catalase (CAT) activities and higher malondialdehyde (MDA) concentrations relative to D13 and D16 (
P < 0.05). Hepatic expression of the pro-inflammatory cytokines
TNF-α and
IL-1β was significantly higher in D10 than in D16, and
IL-1β was also more abundant in D13 than in D16 (
P < 0.05). In summary, between 13 and 16 days after opening, as the training feeding time is postponed, the growth performance and domestication rate of
S. chuatsi larvae significantly improve, intestinal development and digestive capacity significantly enhance, and the antioxidant capacity and immune capacity of the liver are significantly improved. The recommended starting training feeding time for
S. chuatsi larvae is around the 16th day after opening. This study provides a certain theoretical basis for the early feeding strategies of
S. chuatsi larvae and offers a theoretical foundation for solving the problem of supplying
S. chuatsi larvae as feed