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Effects of different herbal extracts on the growth and immune defense of fish were researched in the last decade. The aim of this study was to determine the dietary effects of thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis) and fenugreek (Trigonella foenum graecum) as a feed additive on haematology, innate immune response, and disease resistance of tilapia (Oreochromis mossambicus). In total 228 healthy fish tilapia were divided into four groups (57 fish in one group) and fed diets supplemented with thyme, rosemary and fenugreek at levels of 1%, respectively; fish in the control group were fed diet without any spices. Fish were fed ad libitum three times a day for 45 days. All fish of the experimental groups significantly (P < 0.05) enhanced phagocytic activity, haematocrit, white blood cell, red blood cell, neutrophil and monocyte counts in blood. Significant (P < 0.05) increase of plasma myeloperoxidase and lysozyme activity was found in fish receiving a feed supplemented with fenugreek after 30 days. Respiratory burst activity was non-significantly (P > 0.05) changed during the whole experiment. After 45 days of feeding, fish were injected intraperitoneally with 100 μl of Streptococcus iniae (8 × 10 8 colony forming unit). The cumulative mortality was 22%, 27% and 31% in fish receiving diets supplemented with 1% thyme, rosemary and fenugreek, respectively, compared to 61% mortality in the control group. The results indicate that all three supplements used improved the haematological status, non-specific immune response and disease resistance of tilapia against S. iniae; this is the first similar study.

Dietary mannanoligosaccharide (MOS) from commercial product, Bio-Mos supplementation, has been examined for its effects on weight gain and feed conversion of domestic mammals and birds, but very few studies have evaluated the responses of aquacultural species to MOS. A feeding and digestibility trial was performed to asses the potential beneficial effect of two levels of Bio-Mos on growth, feed utilization, survival rate and nutrientsÕ digestion of gilthead sea bream (Sparus aurata) with an initial average weight of 170 g. Bio-Mos was added at 2 or 4 g kg )1 to a fish mealbased control diet, and each diet was fed to triplicate groups of 1-year-old gilthead sea bream. After 12 weeks, there were no differences in survival rate among fish fed experimental diets (P > 0.05). It was observed that a significant improvability existed for both growth and feed utilization in fish fed diets supplemented with Bio-Mos (P < 0.05). Body proximate composition remained unaffected by Bio-Mos supplementation in fish fed experimental diets (P > 0.05). Apparent digestibility values for protein, carbohydrate and energy were appreciably affected by the inclusion of two different levels of Bio-Mos, only lipid digestibility was the exception. In conclusion, the results of this trial indicate that 2 g kg )1 dietary supplementation with BIO-MOS seem to be most positive for gilthead sea bream production. KEY WORDS

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A feeding trial was performed to assess the potential beneficial effect of two levels of mannanoligosaccarides (MOS) on the growth performance, feed utilization, hematological parameters, and liver histopathology of gilthead seabream Sparus auratus (also known as gilthead bream). Mannanoligosaccarides were added at the rates of 2 and 4 g/kg to a fish-meal-based control diet, and each diet was given (twice daily [midmorning and midafternoon] to apparent satiation) to triplicate groups of gilthead seabream growers (mean weight = approximately 170 g) in sea cages. The trial lasted 12 weeks, and the average ambient water temperature ranged from 19.6 degrees C to 24.7 degrees C during the experimental period. At the end of the experiment, fish attained market size (350-450 g) and their health status was evaluated by blood analysis and liver histology. There were no differences in survival rates among fish fed experimental diets. However, there were significant improvements in both growth and feed utilization among fish fed diets supplemented with MOS. Hemoglobin (Hb) and hematocrit (Ht) levels and erythrocyte, leukocyte, and thrombocyte (Thr) counts were unaffected by any dietary MOS. The levels of Hb (g/dL; mean +/- SD) and Ht (%; mean +/- SD) were 11.0 +/- 2.5 and 45.6 +/- 6.7 for the control group, 11.1 +/- 1.7 and 39.3 +/- 8.0 for the 2-g/kg group, and 11.2 +/- 1.9 and 40.2 +/- 8.4 for the 4-g/kg group. The mean Thr count ranged from 47.6 to 53.8 x 10(3)/mm3. Despite the apparently higher Thr counts for fish fed diets supplemented with MOS, these differences were not significant. Moreover, no histopathological differences were observed in liver tissue cross sections between control and treatment groups. These results suggest that supplementation of diets with MOS had no significant effects on general fish health.

A feeding study with Two-banded Seabream Diplodus vulgaris was conducted to determine the effects of replacement of fish oil (FO) by unrefined peanut oil (PO) on growth performance, feed utilization, body composition, fatty acid composition, and serum biochemical and hematological variables. Three isonitrogenous (35.8%) and isoenergetic (21.15 kJ/g) diets were formulated by replacing dietary FO with PO at levels of level 0% (PO 0 ), 50% (PO 50 ), or 100% (PO 100 ). Fish were fed twice a day until satiation for an experimental period of 8 weeks. The best growth performance was observed in fish fed with the PO 0 and PO 50 diets. A significant increase was observed in hematocrit and mean corpuscular volume levels of fish fed with PO 50 diet compared with the other groups. Hemoglobin, mean corpuscular hemoglobin, total protein, albumin, and globulin were not affected by dietary PO treatment and did not differ among experimental groups. The glucose level was highest in the PO 100 group. Triglyceride and cholesterol levels were lower in fish fed diets with PO inclusions than in those fed the control diet. The fatty acid composition of fish was significantly affected by the experimental diets. Glutamic oxaloacetic transaminase, glutamic pyruvictransaminase, lactate dehydrogenase, and alkaline phosphatase were not affected by dietary PO treatment. The n-3:n-6 ratio in fish fed the PO 0 diet was also higher than in fish fed the PO-supplemented diets. The results of the present study showed that FO could be substituted by PO up to 50% in Two-banded Seabream diets without any negative effect on growth performance or serum biochemical and hematological features.The marine aquaculture industry in the Mediterranean region is mainly concentrated on two fish species, namely the Gilthead Seabream Sparus aurata and European Seabass Dicentrarchus

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