عرفان كريميان

The main objective of this study was to investigate the effect of incorporating grape pomace into the rearing substrate for yellow mealworm larvae (Tenebrio molitor) and to evaluate the efficacy of the enriched larvae as a substitute for fishmeal in the diet of common carp (Cyprinus carpio). The research was done into two phases: the impact of adding grape pomace on mealworm larval rearing and the assessment of using the reared larvae in fish growth and nutrition. In the first experiment, mealworm larvae were reared on three experimental substrates: wheat bran (c), wheat bran supplemented with 10% grape pomace (g10), and wheat bran supplemented with 25% grape pomace (g25), each with three replicates. Measured parameters included growth indices, larvae proximate composition (moisture, protein, fat, ash), chitin content, and total antioxidant capacity of the larvae. In the second experiment, the effect of replacing 70% of fishmeal with powdered mealworm larvae from the first experiment was evaluated. A total of 108 juvenile common carp were fed for 60 days with four experimental diets: a negative control diet without fishmeal replacement (C-), a positive control diet with fishmeal replacement using larvae reared on a substrate without grape pomace (C+), an experimental diet with fishmeal replacement using larvae reared on a substrate containing 10% grape pomace (G10), and an experimental diet with fishmeal replacement using larvae reared on a substrate containing 25% grape pomace (G25). The experiment was conducted with four treatments and three replicates. Growth and feeding indices, survival rate, proximate composition of muscle tissue, and total antioxidant capacity in liver tissue were assessed. Results from larval rearing on the three substrates indicated that, at the end of week six, larvae reared on the substrate with 10% grape pomace exhibited significantly higher mean weight and weight gain percentage compared to the control group (P < 0.05). In terms of nutritional value, the 10% grape pomace substrate resulted in larvae with the highest protein content (P < 0.05), whereas the 25% substrate showed the lowest protein level. Larval fat percentage significantly increased with higher levels of grape pomace. Ash content was lower in both the 10% and 25% grape pomace treatments compared to the control, but moisture content showed no significant differences. Chitin content in larvae was not influenced by substrate type (P > 0.05). Total antioxidant capacity of larvae reared on the 10% grape pomace substrate was significantly lower than that of the control and 25% grape pomace groups (P < 0.05). Results from the second experiment demonstrated that mean body weight, weight gain percentage, specific growth rate, and absolute growth rate in both time intervals (days 1-30 and 1-60) were significantly higher in the G10 group compared to the other groups (P < 0.05). Fish length and condition factor showed no significant differences among groups (P > 0.05). Feed conversion ratio was significantly lower in the G10 group, while feed efficiency ratio and protein efficiency ratio were higher compared to the other groups. Conversely, the G25 group exhibited the highest feed conversion ratio and the lowest feed efficiency ratio and protein efficiency ratio relative to the control. Fish in the G10 and G25 groups showed significantly higher survival rates in both time intervals compared to the control. Additionally, muscle tissue from fish fed the G10 and G25 diets had significantly higher protein percentages and lower moisture content compared to the control. Muscle fat and ash percentages showed no significant differences among groups. Total antioxidant capacity in liver tissue was higher in the positive control, G10, and G25 groups compared to the negative control (C-), although significant differences were observed only between the positive control and G25 groups versus the negative control (P < 0.05). The findings of this study indicate that incorporating grape pomace at a 10% level not only positively influences the performance and nutritional value of yellow mealworm larvae but also enables the use of their powder as a 70% replacement for fishmeal, leading to improved performance indices in cultured fish over a 60-day rearing period.

Aloes as a source of bioactive compounds can have a special situation in aquaculture. In this Study, it was tried to investigate the effects of dietary aloe vera on growth performance, some biochemical and reproductive characteristics of convict cichlid (Amatitlania nigrofasciata). For this purpose, 120 fish including males (length and weight 6.03 ± 0.75 cm and 4.45 ± 1.62 g) and females (length and weight 6.1 ± 0.74 cm and 4.97 ± 1.98 g, respectively) were maintained in five experimental groups including 0, 0.1, 0.5, 1 and 2% of aloe powder in the laboratory of the fisheries Department of University of Kurdistan for 75 days. The results showed that the body weight (male) and standard length in males and females did not differ significantly between groups (p<0.05). However, there was a significant decrease in the body weight of the female by 1% compared to 0.1%. The percentage weight gain and specific growth rate in treatments with low and moderate concentrations of aloe vera powder were the highest for males (0.1 and 1%) and females (0.1%). Regarding condition factor no significant difference was observed. Changes in gonadosomatic index of male between 2% treatment (with the lowest amount) compared to control and 1% treatment and sperm count were significant only between 1% treatment (the highest amount) compared to 0.1% and 2% treatments. In determination of hepstosomatic index, the 2% treatment with the lowest value had a significant difference compared to other treatments (p<0.05). The results of determination of reproductive indices of the female also demonstrated that only the number of eggs of the 0.1% treatment with the highest value compared to the 1% and 2% treatments and the absolute fecundity of the 0.1% treatment had a significant difference compared to the other treatments (p<0.05). The effect of aloe vera powder on cholesterol, triglyceride and protein of testis and cholesterol and triglyceride of ovary was significant (p<0.05). The highest amount of testosterone was observed in males at 1 and 2% and in females in 0.1 and 1% A. vera supplemented diet. The trend of changes in testicular 17-beta-estradiol between the control treatment and other treatments was regular and decreasing, but in female’s low concentration of aloe vera powder had an increasing effect (p<0.05). Overall, our findings indicated that dietary aloe vera at low and moderate concentrations had a positive effect on improving most of the studied factors of Convict cichlid.

Supplying safe and sufficient drinking water is one of the important management issues of human societies. The entry of various pollutants into the lakes causes nitrification, algal bloom and unpleasant taste and odour of the water. Therefore, the current study was conducted with the aim of investigating the nutritional effect of silver carp in controlling the algal communities of Gheshlagh dam and reducing the taste and odour of drinking water in Sanandaj city, during 4 periods from September to March 2021. For this purpose, the planktonic composition of the environment and digestive system of silver carp was investigated. Sampling of water and fish was done in two dam stations, and then in the laboratory, plankton composition of the environment, biometry, nutritional indicators, reproduction and contents of the digestive system were studied. In the investigation of the planktonic population of the environment, Bacillariophyta phylum with 70% and Arthropoda phylum with 54% were found to have the highest density of algae and zooplankton. Based on the results of four age groups of fish 3+ to 6+ years, the average weight of the fish was 1130.4 grams and the average total length was 482.7 mm. The average index of the relative length of the intestine and the condition index were 4.3 and 0.98, respectively, and the index of intestinal emptying was zero. The results of the examination of the contents of the digestive system of fish showed that 54 genera and species of phytoplankton and 11 genera and species of zooplankton were identified, which included 37 genera and species of phytoplankton and 16 genera and species of zooplankton in the environment. In the digestive system, Bacillariophyta branch with 54% and Chlorophyta with 43.8%, and among zooplanktons, Rotifera and Ciliophora branches had the highest zooplankton density with 59% and 40%, respectively. In the diet of fish of both stations, the genus Dinobryon and Melosira and in the investigation of phytoplankton of both lake stations, the genus Melosira had the highest density. The results of the Ivlev index showed that the Bacillariophyta branch with 45% had the highest frequency in the silver carp diet. Also, the genus Melosira In two stations, with a value of 100%, it had the highest abundance in prey. Also, Fragillaria, Cyclotella and Dinobryon with 100 percent in station 1 and 94, 88.9 and 88.9 percent in station 2, they had the highest frequency. The results of the sexual maturation index showed that the environmental conditions necessary for the growth and development of the testis and ovary tissues of silver carp in the Gheshlagh dam lake of Sanandaj are unsuitable and it is most likely that there is no possibility of natural spermation and ovulation of this species. In general, it seems that silver carp is an effective species in controlling the algae load in lakes.

The aim of the present study was to investigate the algae structure as one of the important causes of water quality problems, including unpleasant taste and odor, in the Sabdalo reservoir. For this purpose, the physical and chemical factors of water (total hardness, electrical conductivity, turbidity, pH, phosphate, nitrate, calcium, magnesium, and sodium) and algal structure were investigated at four stations, including the treatment station, Barujekun, Kwpich and Benirzan. The results showed that a total of 7 phylluum (Bacillariophyta, Dinoflagellata, Chlorophyta, Cyanophita, Euglenophyta, Charophyta, and Chrysophyta), 30 families, and 36 genera and species were identified, with Bacillariophyta and Chlorophyta phylluum having 13 species (36%) and 12 species, respectively. (33%) were the haighest and Dinoflagellata, Charophyta with 3 species (8%) and Cyanobacteria, Euglenophyta branches with 2 species (6%) and Chrysophyta branches with 1 species (3%) had the least phylluum. During the study period, the highest density of phytoplankton population with 164572 cell/l was observed in July and the lowest density was observed in February with 860 cell/l. In this study, changes in the composition and density of algae were observed at the different sampling times and locations. Also, the results of determining phytoplankton population structure indices showed that the highest and lowest Shannon indexes were obtained in June with 2.048 at the water treatment plant station and in February 0.34 at Barujekun, respectively. The highest Margaluf richness index was in the summer with 1.2 in July at the treatment plant station and the lowest in February at the Banirazan. The highest value of Simpson index was in February at the Benirzan and Kwpich, which was about 0.9, and the lowest value was 0.5 in July at the treatment plant station. Despite obtaining proper information about the algal composition of the raw water of the refinery and the drinking water distribution network of Baneh, to find the main reasons for the taste and odor, a more comprehensive study should be conducted by examining more physical and chemical factors of water. Based on the results of this study, it was found that algal communities can be one of the main factors in the taste and odor of drinking water in Baneh.