AQUATIC PHYSIOLOGY AND BIOTECHNOLOGY
Year:2018 | Volume:6 | Issue:2|Papers Count:8

This study was conducted to investigate the effect of feeding strategies on growth performance and hematological parameters of Siberian sturgeon (Acipenser baerii) at different sizes for 45 days. Experimental treatments were including large fish with satiation feeding (LA); small fish with satiation feeding (SA); large fish with restricted feeding (LR); small fish with restricted feeding (SR); large starved fish (LS) and small starved fish (SS). Mean weights in large and small fish were 465. 75± 11. 18g and 250. 40± 12g, respectively. Final weight in the LS and SS groups were significantly lower than the other groups (P<0. 05). Hematological indices showed no interaction between feeding strategy and fish size (P>0. 05), but monocyte values were significantly higher in LA treatment compared to the LR treatment (P<0. 05). The present study revealed that feed deprivation has severe negative impacts on small fish while in restricted feeding treatments, these negative impacts were lower and the fish adapted to feed restriction period. Furthermore, the result of the present study indicated that various feeding strategies in both sizes had no adverse impact on hematological indices in Siberian sturgeon.

Environmental quality assessments recommend use of sessile invertebrates. Because, they are unable to escape from environmental deterioration. In addition, the ability of adaptive responses to such environmental change, would determine its survival and reproduction potential. The organism adaptability may therefore be defined by its capacity to adjust the physiology to operate with optimal efficiency in a variable environment. Indicators that are discussed in this field for Azumapecten ruschenbergerii, at the Chabahar Bay and in the time before and after the monsoon, include: the ratio of consumed oxygen to excreted nitrogen and body condition index. The first is widely used to study the metabolism of animals. The second is the occupied space of internal volume of the shell by the body. Accordingly, stress indices were determined and statistically evaluated. The average of both indices was associated with significant changes (increase for the first and decrease for the second one) in relation to pre-and post-monsoon period (P<0. 05). Evaluating both indicators suggests less environmental stress in the post-monsoon period to this bivalve living in sampling sites.

The Caspian Sea salmon (Salmo trutta caspius) is anadromous fish which has economic value and high popularity. In this study, the effects of vitamin E and B2 were investigated on growth performance, hematological and immunology parameters. This study does on 750 fish. Fishes with an initial weight of 20± 3g were divided into 10 groups, one was the control group and other groups received different doses of vitamin E and B2. 15, 20, 25 mg/Kg vitamin B2, 100, 200 300 mg/Kg vitamin E and 15+100, 20+200 and 25+300 mg/Kg mixture of vitamin B2+E in T1 to T9, respectively. Significant differences were observed in final weight and length of different treatments (P<0. 05). The lowest weight and length increment was seen in the control group. Also, the best FCR and the highest SGR, GR, BWI, and CF were observed in T8, the largest WBC, RBC, IgM, and lysozyme were measured in T9 and the largest MCHC, MCH, MCV, Hb and total immunoglobulin were recorded in control group. The best performance was obtained in T8 (20B2+200E). Overall results showed that adding the mixture of 2 vitamins improve growth and performances of the immune system and has larger effects on growth.

The present study was carried out to investigate the dietary effects of different levels of synthetic astaxanthin on reproductive performance of giant freshwater prawn (Macrobrachium rosenbergii). 24 broodstock prawns were randomly distributed into 3 treatments considering male to female ratio as 1: 3 in duplicates. Experimental diets were supplemented with an amount of 0 (as control), 50 and 100 mg. Kg-1 astaxanthin. Prawns were fed on experimental diets in a ratio of 2% biomass for a period of 45 days. Total carotenoid, number of eggs per gram, eggs diameter, hatching rate and number of larvae after hatching as broodstock reproductive performance indices while larval somatic index (LSI) and larval length were measured to assess larval quality. Results showed that diet supplementation with synthetic astaxanthin significantly affects the number of eggs and number of larvae after hatch (P<0. 05). Also, a significant difference was observed in total carotenoid, eggs diameter, LSI and larval length (P<0. 05). Thus, based on these results and being more costeffective 50 mg. Kg-1 supplementation level is recommended to improve giant freshwater prawn reproductive performance.

Finding economically viable and environmentally friendly protein sources to fish meal (FM) replacement in carnivorous fish feeds is one of the main challenges for the sustainability of the aquaculture industry. In this study, FM was replaced by Poultry by-product meal (PBM) levels of 0 (control), 15, 25, 35, 45 and 55% in Sparidentex hasta formulated diets. Sobaity sea-bream with an average initial weight of 29. 27± 0. 06g and standard length of 8. 7± 0. 36cm were randomly assigned to 18 tanks (300L) at stocking density of 20 fish per tank (6 treatments, triplicate) and were fed with experimental diets for 60 days. At the end of feeding trial, no significant reduction were observed in growth indices between the control and the fish fed up to 55% replacement. Hematocrit, hemoglobin, MCHC and serum albumin, globulin, total protein, glucose, urea and acid uric, aspartate aminotransferase had no significant differences between fish fed the PBM based diets and control diet (P>0. 05). Serum alkaline phosphatase, cholesterol and calcium showed higher value in PBM diets than control, although triglyceride was higher in control diet than PBM diets. The results indicated that FM can be substituted successfully by PBM in the diet of S. hasta juveniles up to 45% without adverse effects on serum biochemical parameters.

In this study, a HindIII Satellite DNA (168bp) was isolated from Russian sturgeon, Acipenser gueldenstaedtii and was used as a probe for fluorescent in situ hybridization (FISH) with the chromosomes of Persian sturgeon and Russian sturgeon. After obtaining suitable chromosomal preparations from the fishes through leukocyte culture and labeling the probe with Spectrum orange (Orange-dUTP) through Nick translation method, the probe was hybridized with chromosomes of the fishes on the microscopic slide. In the studied chromosomal preparations, the hybridization colored signals were clearly visible. Counting the produced signals in twelve chromosomal preparations of three fishes from each species showed that the mean number of the signals in the chromosomal preparations of the Persian sturgeon and Russian sturgeon were 67± 3 and 68± 4 respectively. In this study, accurate kind determining of chromosomes and HindIII SatDNA site on the chromosomes were impossible due to the presence of microchromosomes and heterogeneity of shapes and sizes of colored signals.

Aloe vera is a rich resource of antioxidants, vitamins, minerals, mineral acids and enzymes. Studies showed that Aloe vera can affect the physiology of reproduction in animals. The aim of this trial was to evaluate the effect of different levels of the ethanol extract of the Aloe vera plant on reproduction and growth performance in Xiphophorus helleri. Powder extract was added to the diet in 4 levels: 200, 400, 800 and 1600 mg/Kg and control group without any extract. At the end of the experiment the results showed that there were significant differences in final weight, final length, weight gain, weight gain percentage and SGR in fish fed 800 mg/Kg compare to control group. Also, there were remarkable differences in the gonadosomatic index in treatment 4 and 5 than 1, 2 and 3. In conclusion, Aloe vera extract can improve the growth performance, fecundity and gonadosomatic index in Xiphophorus helleri.

The aim of this study was investigated the accumulation of lead and chromium in liver and gills of tigertooth croaker (Otolithes ruber) and use of histopathological changes of gills and liver to evaluate the effects of Oman Sea pollutants. Tigertooth croakers with an average weight of 382. 5± 1. 93g were collected from four stations include: Konarak desalination, Beris, Pasabandar and Gowatr and samples of liver and gill tissues were studied based on the routine histological methods. Chromium and lead concentrations in liver and gill tissues were measured by atomic absorption spectrophotometer. Most of the observed changes in liver tissue were destruction, vacuolation of hepatocytes, expansion of disk space, recession bile, hyperemia and hemorrhage, melanomacrophage centers, fat accumulation, pyknosis and necrosis. Also, in the gills, lifting epithelium, clubbing, hyperplasia and hypertrophy of chloride cells, mucus secretion, shorter blade and necrosis were recorded. The results showed that the Pasabandar station had the highest severity of tissue lesions and the highest bioaccumulation of metals in liver and gill tissues. Histopathological lesions of the tissue in tigertooth croaker can be considered as a bioindicator of the negative effects of contamination in the studied area.