RESUMEN
In this study, 54 five-year-old farmed female beluga at stage II of sexual maturation were treated with 0 [control], 0.2, 0.4, 0.8 and 1.6 g of dietary soy equol [EQ] and genistein [GE] per each kilogram [kg] of diet during a year. Blood samples were collected and ovarian biopsy was performed quarterly. Results showed that 64.4% of the Huso huso sexually matured at EQ 0.4 g/kg and reached stage IV of sexual maturation. Oocytes diameters increased significantly at all concentrations of EQ and 0.2, 0.4 and 0.8 concentrations of GE and reached a maximum [3 +/- 0.2 mm] at 0.4 g/kg EQ concentration at the end of experiment [P<0.05]. Blood plasma testosterone [T] level was 0.3 +/- 0.06 ng/ml at the beginning and reached a maximum [21.04 +/- 1.91 ng/ml] at EQ 0.4 g/kg at the end of the experiment [P<0.05]. 17a-estradiol [E2] levels increased significantly at some concentrations of GE and EQ at the end as compared to the beginning, reaching a maximum [12.6 +/- 1.04 ng/ml] at EQ 0.4 g/kg at the end of the experiment [P<0.05]. 17- hydroxy progesterone [17á-OHP] levels showed no significant difference [P>0.05]. In conclusion, EQ at a 0.4 g/kg concentration showed more powerful positive reproductive effects than other concentrations of EQ and GE in farmed female H. huso. Comparatively, EQ showed more estrogenic effects on ovary development in comparison to GE concentrations. Its use is therefore suggested as an additive to diets to induce ovary development in Huso huso
RESUMEN
Vitamin C is an essential nutrient for teleost fish. It plays vital role in immune system function. A feeding trial was conducted to determine the effects of different levels of dietary vitamin C supplement on growth performance, hematological indicators and response to heat stress in rainbow trout [Oncorhynchus mykiss] fingerlings kept at different densities. The fingerlings [initial weight of 2.1 +/- 0.1] were reared in triplicate groups in fiberglass tanks at two different densities [400 and 600 /m[2]]. The fish were fed with four experimental diets containing different levels of vitamin C [0, 100, 200 and 1000 mg vitamin C /kg diet] for 9 weeks. To evaluate the effect of heat stress on survival, fish were exposed to different temperatures [24, 26 and 28 °C] at the end of feeding experiment. Growth performance in fish which fed diets containing different levels of vitamin C [100, 200 and 1000 mg /kg diet] was significantly [p<0.05] higher than those fed diet without vitamin C supplement. In terms of hematological indicators, it was shown that different levels of vitamin C significantly [p<0.05] effected the hematocrit, hemoglobin and red blood cell [RBC] count. However, it did not make any effect on the MCH and MCHC values. On the other hand, stocking density only had significant effect on RBC count. Survival of fish which fed diets containing different levels of vitamin C was significantly [p<0.05] higher than those fed diet without vitamin C in response to heat stress