Effects of Melatonin on the Growth and Diurnal Variation of Non-Specific Immunity, Antioxidant Capacity, Digestive Enzyme Activity, and Circadian Clock-Related Gene Expression in Crayfish (<i>Procambarus clarkii</i>)
This study aimed to investigate the effects of dietary melatonin supplementation on growth and diurnal non-specific immunity, antioxidant capacity, digestive enzyme activities, and circadian clock-related gene expression in crayfish (<i>Procambarus clarkii</i>). A total of 500 healthy ju...
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| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-03-01
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| Series: | Fishes |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2410-3888/10/3/114 |
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| Summary: | This study aimed to investigate the effects of dietary melatonin supplementation on growth and diurnal non-specific immunity, antioxidant capacity, digestive enzyme activities, and circadian clock-related gene expression in crayfish (<i>Procambarus clarkii</i>). A total of 500 healthy juvenile crayfish (6.68 ± 0.31 g) were randomly distributed into five groups with four replicates each and fed five different diets supplemented with melatonin at 0, 25, 50, 75, and 100 mg/kg for 60 days. The results indicated that dietary supplementation of 50 mg/kg melatonin significantly increased the weight gain rate (WGR), specific growth rate (SGR), and survival rate (SR) of juvenile <i>Procambarus clarkii</i>. However, no significant differences were observed in the hepatosomatic index (HSI), meat yield, and condition factor (<i>p</i> > 0.05). When the dietary melatonin level was 50 mg/kg, the activities of LZM and ALP in the hemolymph of <i>Procambarus clarkii</i> were higher than the levels at both 15:00 and 03:00, while the activities of AST and ALT remained at lower levels during these two time points. It also significantly upregulated the mRNA expression levels of <i>Clock</i>, <i>Per1</i>, <i>Cry1</i>, <i>Tim1</i>, and <i>Tim2</i> in the hepatopancreas (<i>p</i> < 0.05). Furthermore, dietary melatonin at 50 mg/kg significantly reduced the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as the malondialdehyde (MDA) content across day and night (<i>p</i> < 0.05). No significant differences were found in acid phosphatase (ACP) at 15:00, alkaline phosphatase (ALP), and amylase (AMS) activities in the hepatopancreas and intestine at 3:00 among the groups (<i>p</i> > 0.05). At 15:00, supplementation with 50 mg/kg significantly upregulated <i>Bmal1</i> mRNA expression (<i>p</i> < 0.05). Melatonin supplementation at 50–75 mg/kg resulted in significantly higher levels of TP, LZM, ALP, and CAT activities, as well as significantly higher mRNA expression of <i>Clock</i>, <i>Bmal1</i>, <i>Cry1</i>, <i>Per1</i>, <i>Tim1</i>, and <i>Tim2</i> in the hepatopancreas at 3:00 compared to 15:00 (<i>p</i> < 0.05), with the opposite trend observed for MDA content (<i>p</i> < 0.05). No significant differences were found in ACP, ALT, and AST activities between 3:00 and 15:00 among the groups (<i>p</i> > 0.05). Thus, dietary supplementation of 50 mg/kg melatonin could promote the growth of juvenile <i>Procambarus clarkii</i>, enhance their non-specific immunity and antioxidant capacity during both day and night, increase the activities of digestive enzymes in the hepatopancreas and intestine, and regulate the expression of circadian clock-related genes. |
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| ISSN: | 2410-3888 |