Determining nutritional requirements in Beluga (H.huso) from larval stage to marketable size

• Main Authors: Mohseni, Mahmoud, Bahmani, M., Pourali, H.R., Alizadeh, M., Jamalzad, F.
• Format: Book
• Language: Persian
• Published: Iranian Fisheries Science Research Institute 2007
• Subjects: Aquaculture; Biology; Beluga; Beluga*
• Online Access: http://aquaticcommons.org/25107/; http://aquaticcommons.org/25107/1/85.610.pdf

Growth experiments were designed and conducted in several phases in order to determine the most suitable starter diet, to determine the effects of different levels of protein and energy and also to determine the effects of different ratios of carbohydrate to fat on growth and body composition in farmed Huso huso from the larval stage up to the marketing stage. Phase one Growth experiments were conducted in a random statistical design to compare growth trends in H. huso larvae (mean weight 105.02 ± 0,02 mg) without being adapted to formulated diets. Experiments were conducted in fibreglass tanks (500 litre capacity) under similar culture conditions. Four replicates were run for each experiment. Larvae were fed four types of formulated diets (Diet A=100 % formulated diet produced in the International sturgeon Research Institute, Diet B=formulated diet imported from Holland, Diet C= formulated diet imported from France, Diet D= a mixture of Diet A + 10% gammarus) 8 times a day to satiation for a period of 49 days. The results obtained were compared with those obtained for the control group that was fed live food (Daphnia and Artemia). Mean water temperature during the experimental period was 18.52 ± 0.48 °C and mean dissolved oxygen was 7.35 ± 0.18 mg/l. The first signs of food granules were observed in the guts of the larvae after 12 h of the first feeding. All experimental groups were adapted to granulated diets on day 3 to day 5. In the beginning of the experimental period the larvae showed a no normal distribution (P 0.05) in terms of weight and length. However significant differences were observed in the end of the experimental period among the different groups studied in terms of growth, specific growth rate and food efficiency (P 0.05). Growth in group B and D were significantly higher than that in other groups except for the control group (P 0.05). It may thus be concluded that the olfactory organs of larvae took to Diet B (may be due to its composition) and to the diet D (because of its odour, texture and suitable flavour) more readily than other diets. At the end of the experimental period, maximum survival (98%) belonged to the control group. Survival rate in Group B and Group D was 90 % and 86.5%, respectively (P 0.05). Minimum survival belonged to fish fed Diet A (29.7%) and Diet C (45.5%). With regard to the adaptability of larvae to formulated diets, survival rates and growth and development in larvae we may conclude that the effects of different formulated diets on growth in larvae can be conducted on larvae with a mean body weight between 100 to 120 mg. In this weight class the digestive system and olfactory organ are fully developed and play a vital role in searching for food particles.