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Volume 4, Issue 3 (12-2015)
Abstract
This study was carried out to evaluate the effect of different sources and levels of carbohydrate (glucose and corn starch) on growth performance and carcass composition of juvenile Siberian sturgeon (Acipenser baerii). Two weeks after acclimatization period to rearing conditions and basal diet, the number of 120 Siberian sturgeon juveniles weighing 25.64 ± 2.80g were randomly distributed into 12 fiberglass tanks in four treatments (glucose 15%, glucose 30%, corn starch 15% and corn starch 30%) in three replicates and kept at a density of 10 fish per tank (one fish per 35 liter) for a period of 8 weeks. Results showed that final weight, final total length, percentage of body weight increase, specific growth rate, mean daily growth, protein efficiency ratio and condition factor in fish fed corn starch 15% were high in comparison with other treatments (P>0.05). Fish fed corn starch 15% had the lowest (P>0.05) food conversation ratio. Significant difference was seen between fish fed corn starch 30% with fish fed glucose 15% in HSI (P0.05). The highest content of carcass protein was seen in corn starch 15% that showed significant difference with treatments glucose 15% and 30% (P
Roghayeh Jafari Taraji, Alireza Alishahi, Seyed Mahdi Ojagh, Abbas Esmaeili Molla,
Volume 4, Issue 3 (12-2015)
Abstract
Protein hydrolysate (PH) from viscera of cultured Siberian sturgeon (Acipenser baerii) was produced. To optimize the production conditions, Response Surface Method (RSM) was employed to examine the effects of three different operating conditions, including time, pH, and enzymatic concentration (Alcalase) on the degree of hydrolysis.The mathematical model showed acceptable fitness of the experimental data as R2 equaled 0.97, which indicated that major part of the variability within the range of values could be explained by the model. The results showed that the highest degree of hydrolysis (58.21%) was related to the treatment which happened at the enzymatic concentration of 2%, 60 minutes time, and pH=8. Treatment under hydrolysis condition (i.e., E/S = 2%, Time = 45 min, and pH = 8.5) had the highest protein content (42.37g/l), which was used as an alternative to commercial peptone medium (Triptic soy broth) to assess the growth of Salmonella typhi bacteria from 0 to 48 hours. Although there was an upward trend in growth rate of S. typhi both in control and No. 15 (Alcalase) treatments, the log growth of control treatment was found to be better than that of Alcalase treatment. However, there existed no significant difference between the two treatments.
