JOURNAL OF APPLIED ICHTHYOLOGICAL RESEARCH
Year:2016 | Volume:3 | Issue:4|Papers Count:8

In order to investigate summer diet of Salmo trutto fario, 101 specimen were sampled from the Delichay River (Lar National Park) in 2009. The digestive system content of fishes was studied using eclectic methods including: quantitative analysis of the intestinal contents (number, weight and occurrence of preys), species diversity indices (Species Richness, Shannon-Wiener and Evenness), Costello graphic display method based on the number and weight of preys, and also the new three-dimensional representation of the Costello method. Results showed the following: First, fish feeding strategies was that of generalist and Diptera larvae (%N=73.71) and nymphs of the Ephemeroptera (%N=12.54) had the most importance in the diet of the sample. Second, based on variety indices, sexual dietary differences were not found (p>0.05). Third, the new graphical display of Costello revealed better results compared to other Costello graphical methods due to simultaneous measurement of the influence of the weight and the number of prey items.

To evaluate the feasibility of using the shape of neurocranium in identifying the species of the genus Cyprinion by geometric morphometric technique, 30 specimens of five Iranian species were caught. For this purpose, 17 homologues landmark points were defined and digitized on 2D pictures taken from the dorsal view of their neurocranium. The data (coordinates of the landmarks) were analyzed according to Principal Component Analysis (PCA), Canonical Variate Analysis (CVA) and Cluster Analysis (CA) using MorphoJ and PAST soft wares. The statistical analyses could discriminate five species according to the shape of neurocranium. The key characters that can be used to describe species are the following: C. kais bears the least cranial width at lateral ethmoid region, the least narrowing at mediolateral neurocranium and the least distance between anterior to posterior connection point of palatines. C. macrostomum possesses the least supraethmoid width and there is a notch in its anterior most border and also has the most distance between the anterior to posterior connection points of the palatines. C. milesi has the narrowest and more elongated neurocranium among Iranian Cyprinion genera, and has the narrowest neurocranium in the mediolateral of the neurocranium. In C. tenuiradius, the neurocranium is wide at pterotic region, decreases in mediolateral regions and then increases at lateral ethmoid region. Finally C. watsoni has the widest and shortest supraethmoid among Iranian Cyprinion fishes.

This study aimed to investigate and compare morphometric characteristics of otolith in Scarus fuscopurpureus, Heniochus acuminatus and Chaetodon rafflesii in the coral reefs of Persian Gulf and Oman Sea. Sampling lasted from March 2014 to April 2015. During this period, 26 specimens of S. fuscopurpureus, 8 specimens of H. acuminatus and 11 specimens of C. rafflesii were caught using diving method. Investigation of biometric features of specimen including total length, fork length, and fish weight, in addition to otolith morphometric characteristics and the biometric parameters, including length, breadth, weight, perimeter and area, were conducted. Results indicateda significant correlation between otolith length and otolith weight, fork length and otolith length and between fish length and weight in most of species. The highest correlation was observed in S. fuscopurpureus. Also, the results show significant difference between otolith area and otolith weight in all species (p<0.05). Otolith width did not show a significant difference in any of the species in the sample. Otolith perimeter and otolith length were different significantly (p<0.05) in C. rafflesii but not in S. fuscopurpureus and H. acuminatus (p>0.05). Otolith width had no significantly different in all species (p>0.05). Therefore, the present study indicated that the particular characteristics of sagitta such as otolith area and otolith weight are useful in species identification.

The purpose of this study was to investigate the genetic variety of A. eichwladi, as the local species of the Caspian Sea, using five microsatellite loci (including Reser10, Ca3, Llec-090, LeA-071, and Mfw17) in three sampling stations from Paulrood River, Roodsar. To do so, ninety samples in three sections of Paulrood River were collected. Of the five microsatellite indicators used for genetic evaluation in the present study, only three showed significant results. Analysis of the genetic variety data revealed that the average amount of observed heterozygosity (H0) equals to 1. In addition, the mean of expected heterozygosity (He) is 0.755 among these three stations. Also, the average observed Allel in each genetic station is equal to 5.55 and its range was between 4-8 Allels in genetic stations. The average number of effective Allels (Ne) at the level of station was calculated as 4.276 for these three areas. In this investigating genetic differentiation, Fst and Rst were obtained 0.06 and 0.066 respectively, that indicating low genetic differentiation among the samples. All of the samples showed significant deviation from Hardy-Weinberg equilibrium mostly due to the heterozygosity deficiency. The number of Alleles and observed (Ho) and expected (He) heterozygosity was 4-8 (the average of 5.55) and 1.00 and 0.755 respectively, higher than the amount reported for fresh water fish. Also, analysis of molecular variance revealed the most of the observed diversity was among populations (95%) and there is low diversity within the populations (5%). Results indicated that A. eichwldi has acceptable Allelic richness and considerable genetic diversity in Paulrood River.

In the present study clove oil extract as an anaesthetic in juvenile Persian sturgeon (Acipenser persicus) has been studied. To this end, 150 juvenile Persian sturgeons with average weight of 76.55±2.15 gwere divided into15 fiberglass tanks. Then three treatment groups, one negative control group and one positive control group, each with three replicates, were considered. The fish of control groups were exposed to 50, 100 and 150 mg/l of clove oil extract as anaesthetic, respectively. Results indicated no statistical difference in stages of anaesthesia for different clove oil extract concentrations. Anaesthesia and recovery times were calculated as less than 3 minutes for all drug concentrations. According to histological examination, no pathologic sign was detected in kidney, liver and gill tissues of the sampled fishin the anaesthesia test in different concentrations. In long time exposure (20 minutes) to 150 mg/l clove oil extract oedema and epithelium lifting in secondary lamella of gill was recorded but no pathological sign was observed in kidney and liver tissues. Due to the results of the present study, the 50 mg/l clove oil extract is recommended as a standard anaesthesia for juvenile Caspian sturgeon. Also, elevation of this drug dose to 150 mg/l is acceptable and has no histopathologic effects in this fish.

Betaine and L-carnitine are important supplements in aquaculture industry. The present study was conducted to evaluate the interaction effects of these supplements and oil type on the growth performance, digestive enzymes activity and stress resistance of rainbow trout fingerlings. Four hundred and twenty healthy rainbow trout (initial weight: 9.9±0.1 g) were used. The sample was fed with four treatments (fish oil, fish oil+Betaine and L-carnitine, corn oil, corn oil+Betaine and L carnitine) and three replicates. The amount of Betaine and L-carnitine used in the present study were 500 and 1000 mgr, respectively. Results of two- way ANOVA showed that experimental variables (the supplements and oils) did not affect fish weight gain independently while their interaction effects were significant (p<0.05). Also, the results did not show a significant independent effect of the supplements on the digestive enzymes activity (p>0.05), but significant interaction effect of the supplements and oil was observed on amylase and alkaline phosphatase activity. In addition, the interaction and independent effect of variables on the resistance to environmental stress (salinity, oxygen and thermal) was investigated in fingerlings and the results revealed that oil variable did not affect stress resistance. However, the food supplements, both independently and in interaction with oil, increased fish resistance against thermal stress significantly.

The aim of the present study was to investigate the effects of date palm fruit extracts (DPFE) on growth performance, feed utilization and skin mucosal immunity of common carp fingerling. The sampled carp fingerlings (4.06±0.13 g) were supplied and randomly allocated in 6 tanks at density of 20 fish per tank in triplicate groups. The sampled fish were fed with experimental diets supplemented with 0 (control) or 200 ml kg-1 DPFE for 8 weeks (2 treatments with 3 replicates) for 8 weeks. At the end of feeding trial (8 weeks), growth performance and feed utilization parameters (final weight, Specific Growth Rate [SGR], Food Conversion Ration [FCR]) as well as skin mucus immune parameters (total immunoglobulin levels, lysozyme, protease and alkaline phosphatase activity) were measured. The results showed that dietary DPFE remarkably increased growth performance parameters and decreased FCR compared to the control group (p<0.05). Also, evaluation of total immunoglobulins, lysozyme, protease and alkaline phosphatase activity in the revealed significant increase in carp fingerlings fed diet supplemented DPFE (p<0.05). These results showed that DPFE can be considered as a beneficial feed additive to improve growth performance and immune response of carp fingerlings.

In the present study, the effects of dietary tomato waste powder (TWP) on blood serum biochemical parameters and growth indices of Common carp (Cyprinus carpio) were evaluated. To do so, 180 Common Carp fingerlings specimens with the initial average weight of 9.20±1.75 g were randomly distributed in to 15 aquaria (five treatments and three replicates) with density of 12 fish per aquarium and equal environmental conditions. After two weeks adaptation, the fish were fed with five levels including 0 (control), 50, 100, 150 and 200 g tomato waste powder/kg diet during 12 weeks. The results showed that the AST (aspartate aminotransferase), LDH (lactate dehydrogenase), Glucose and Cortisol levels were significantly different (p<0.05) in treatment groups compared to the control group. But no significant difference was observed in levels of ALT (alanine aminotransferase) and ALP (alkaline phosphatase) in all treatment groups compared to the control group (p>0.05). The highest levels of daily growth rate, specific growth ratio and feed efficiency indices were recorded in group treatment of containing 50 g tomato waste powder/kg diet. Also, the feed conversion rate index in fish fed with 50 g tomato waste powder/kg diet has improved. The results suggested that addition of tomato waste powder at the level of 50 g/kg diet improves growth indices and also reduced the production costs and consequently, can made to more profitability.