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The importance of seaweed as a possible supplement or an alternative protein source for Asian seabass (Lates calcarifer) has been recently recognized by several studies. In the present study, Asian seabass with an initial mean body weight of 29.00 ± 1.00 g has been used as a model organism to establish the effects of dietary Sargassum ilicifolium and Padina australis, as partial substitution of fish meal on growth performance, body composition, hemato-immunlogical response, digestive enzymes and immune and growth-related genes. Three diets were formulated in which fish meal (FM) was replaced by S. ilicifolium (SIM 6) and P. australis meal (PAM 6) at 6% (SIM 6 & PAM 6, respectively) whereas in the control diet (C), FM was not replaced with macroalgae. Asian seabass juveniles were fed for six weeks with experimental diets. At the end of the experiment, growth and feed utilization parameters in PAM 6 were significantly higher than those of the control group (p < 0.05). The P. australis dietary inclusion showed differences significantly in red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), white blood cell (WBC), lymphocytes, neutrophils, and cholesterol contents (p < 0.05). It was observed that the levels of total protein and triglyceride in fish fed SIM 6 significantly increased compared to the other groups (p < 0.05). The skin mucus total immunoglobulin (Ig) and mucus lysozyme in the group fed on PAM 6 were significantly higher than the control group (p < 0.05). The serum total Ig in the group fed on SIM 6 was significantly higher with respect to the control group (p < 0.05). No significant differences were recorded in the contents of the alternative complement pathway hemolytic activity (ACH50) and serum lysozyme among all treatment groups (p > 0.05). There was no significant difference in the contents of protease, lipase, and amylase among all treatments (p > 0.05). At the end of the experiment, the insulin-like growth factor I (IGF-I), lysozyme (LZ), and interleukin-1β (IL-1β) in liver organ in PAM 6 were significantly higher than other treatments (p < 0.05). The results obtained in the present study showed that P. australis as a partial replacement for fishmeal in the diet of Asian sea bass juveniles is beneficial for its immune system and growth performance stimulatory effects. [ABSTRACT FROM AUTHOR]

This research was designed to appraise the single or combined effects of dietary sodium butyrate (SB) and sodium propionate (SP) on growth, serum biochemical parameters, serum and skin mucus immune responses, and expression of immune-related genes in goldfish fry. To design seven experimental groups in triplicates, the fry (n = 315; 5.6 ± 0.1 g) were randomly stocked in 21 tanks (150 L) with a density of 15 fish per tank. In this study, a basal diet (36.81% crude protein, 11.33% lipid, and 3.5% ash) was considered as the control diet and the other experimental diets were formulated by adding SB 0.1% (SB1), SP 0.1% (SP1), SB 0.2% (SB2), SP 0.2% (SP2), SB 0.1% + SP 0.1% (SB1SP1), and 0.2% SB + 0.2% SP (SB2SP2) into the basal diet. The fish were fed ad libitum with the corresponding diets three times per day for 56 days. The current study was measured the serum biochemical and immune parameters, mucus immunity, and the expression of immune-related genes using the blood, mucus, and head kidney samples, respectively. After 56 days, the highest growth rate (2.85 ± 0.04%/day) and the lowest feed conversion ratio (1.65 ± 0.06) were recorded in SB2SP2 treatment (p < 0.05). The serum lysozyme activity enhanced 1.76 folds in the fish fed with SB2SP2 diet compared to the control group (p < 0.05). Moreover, the highest skin mucus lysozyme activity (17.52 ± 1.40 U/mL) was observed in B2SP2 treatment, which showed a 1.69-fold increase compared to the control groups (p < 0.05). Total immunoglobulin levels in the serum and mucus samples of the blended acidifier-supplemented diets were significantly higher than the control group (p < 0.05). The levels of serum alanine aminotransferase, aspartate aminotransferase, glucose, and cortisol significantly decreased in all treated fish compared to the control fish (p < 0.05). The relative transcription levels of tumor necrosis-α, lysozyme, interleukin-1β, and interleukin-8 genes were significantly upregulated in SP2SB2 group compared to the control group. The results of the present study revealed the beneficial synergistic effects of dietary SB and SP, especially at 0.2%, on the growth performance, physiological responses, and immunity of goldfish. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of dietary Citrus bergamia peel oil (CBO) on growth performance, haematological and serum biochemical responses of Nile tilapia, Oreochromis niloticus. Volatile content of C. bergamia peel oil used in study was detected with GC/MS. The 99.47% of the analysed volatile components were identified in decreasing quantities as limonene, linalool and linalyl acetate. The experimental fish were divided into four groups stocked into triplicate tanks (20 fish/tank), and fed daily with an additive-free basal diet containing 0% (CBO0), 0.5% (CBO0.5), 1.0% (CBO1), 2.0% (CBO2) of bergamot peel oil for an 8-week period. Results showed that dietary bergamot peel oil especially at 0.5 g 100 g−1 significantly increased growth performance of fish (p < 0.05). The levels of haemoglobin and haematocrit significantly increased in fish fed with CBO0.5 and CBO1 compared with the CBO0-fed group (p < 0.05), despite no significant difference was observed in CBO2 group (p > 0.05). Highest haematocrit value was found in the CBO0.5 group compared with the control group. The serum glucose of the fish fed with CBO0.5 and CBO1 feeds decreased significantly compared with the control group (p < 0.05). The highest total protein, lowest cholesterol and triglyceride in serum were observed in fish fed with bergamot oil–supplemented groups. According to the results, it was revealed that 0.5% bergamot oil supplementation to Nile tilapia diets optimizes the growth performance, feed utilization and health status related with blood parameters of the fish. [ABSTRACT FROM AUTHOR]