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A 6‐week study was conducted to assess the effect of dietary fishmeal (FM) replacement with Sargassum ilicifolium meal (SIM) at four substitution levels including 0 (control), 3% (S3), 6% (S6) and 9% (S9) on performance of Asian sea bass (Lates calcarifer) juveniles (initial mean body weight of 29.0 ± 1.0 g). Growth performance pronouncedly increased in SIM‐supplemented groups compared to the control (p < .05). Fish fed on the S6 diet had higher pancreatic digestive enzyme activities than other treatments. Supplementing diet with SIM remarkably enhanced red blood cell count compared to the control. Moreover, fish in the control and S3 groups had higher lymphocyte, but lower neutrophil percentages than the S6 and S9 treatments (p < .05). The greatest and the least amounts of the total protein and total immunoglobulins (Ig) in serum were found in the S6 and the control, respectively. The amount of alternative complement pathway activity in the serum of fish in the S9 group was higher than the other groups, whereas higher serum lysozyme activity was found in the S6 and S9 treatments compared to those in the control and S3 groups (p < .05). Total Ig content of the skin mucus in the S6 and S9 groups was higher than the control. The greatest and the least mucosal lysozyme activates were found in the S6 and control, respectively (p < .05). The liver superoxide dismutase activity in the S6 and S9 groups was higher than the other treatments (p < .05). The insulin‐like growth factor‐1 mRNA transcript abundance levels in the liver were greatest and the least in fish fed on the S9 and control, respectively. The expression of lysozyme gene, as indicated by an abundance of mRNA transcript for lysozyme, in the liver was higher in the S6 and S9 groups than the other groups (p < .05). Furthermore, fish fed the SIM‐incorporated diets had higher interlukine‐1β mRNA transcript abundance in the liver compared to the control (p < .05). Overall, according to the findings of this study 6% of dietary FM could be replaced with SIM to improve growth rate and health status in L. calcarifer juveniles.

An 80‐day feeding trial was conducted to evaluate the influence of different short‐term fasting and re‐feeding strategies on growth and physiological responses in yellowfin seabream, Acanthopagrus latus (2.4 ± 0.2 g) fingerlings. The fish were subjected to four different feeding regimes, and the control group fed four times daily to apparent satiation throughout the whole feeding period, while the other three groups were deprived for 2, 4 and 8 days followed by 8, 16 or 32 days of re‐feeding (F2R8, F4R16 and F8R32, respectively) in repeated cycles for 80 days. The fish in the control and F2R8 groups had the highest and the lowest total length, respectively (p < .05). Moreover, fish exposed to F4R16 had the highest hepatosomatic indices, while control fish had the lowest hepatosomatic indices (p < .05). Fish in the F2R8 group relatively had higher catalase and glutathione‐S‐transferase activities than other groups (p < .05). Furthermore, total protease, α‐amylase and alkaline phosphatase activities in the F4R16 and F8R32 were higher than the F2R4 and control groups (p < .05). Overall, this study showed that compensatory growth in weight and length and digestive enzyme activities were observed in the F4R16 and F8R32; however, the increase in the activity of antioxidant enzymes in the F8R32 group indicated that oxidative stress remained after 80 days of re‐feeding in the liver.

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Sixty-day research was conducted to investigate the effects of dietary butyric acid glyceride (BAG) on the performance of Acanthopagrus latus fingerlings (8.59 ± 0.33 g).Experimental feeds were prepared by supplementing a commercial feed (crude protein: 50%, crude lipid: 15%) with graded levels of BAG including 0 (control), 0.25% (BAG0.25), 0.5% (BAG0.5) and 1% (BAG 1). One hundred and twenty fish (10 fish in each tank) were stocked in twelve 300-L tanks then fed with the experimental feeds twice daily. Growth and feed utilization in fish fed BAG-supplemented diets were better than the control (p < 0.05). Fish fed BAG1 diet had more red and white blood cells counts than the other groups. Total immunoglobulin content and lysozyme activity in the skin mucus increased by increasing dietary BAG. Fish in BAG1 group had more skin mucosal alternative complement pathway activity than the other groups (p < 0.05). Liver catalase and glutathione S transferase activities increased in a doseresponse manner to dietary BAG level. Fish in BAG1 group showed higher liver glutathione reductase activity than the other treatments. According to the findings of this study, supplementing diet with 1% of BAG can promote growth performance and health conditions in A. latus fingerlings.