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The development of the marine aquaculture industry has led to the generation of significant amounts of fish wastes. Marine farm wastes exert adverse effects on the surrounding area of the cages. On the other hand, wastes of fish and other aquatic animals are regarded as major sources of valuable natural bioactive compounds, including enzymes, proteins, bioactive peptides, oil, amino acids, collagen, gelatin, calcium, biopolymers, and water-soluble minerals. To investigate the potential of marine fish waste, the whole digestive system of yellowfin seabream (Acanthopagrus latus) was extracted for extraction and identification of trypsin enzyme. Fish (179.93±93.67 g; 184±28.17 cm) were caught from the Persian Gulf and stored at -20 °C. Yellowfin seabream were dissected and their whole digestive systems were removed. Samples were thoroughly washed with distilled water and purified through defatting using acetone and ammonium sulfate precipitation. The following issues were assessed: the total and specific activity of trypsin, protein determination, molecular weight, enzyme activity and stability in different pH values and temperatures. The obtained results indicated that specific activity and protein content of trypsin enzyme were 4.4 U and 3.4 mg/ml, respectively. The molecular weight of 23 kDa was reported for trypsin using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) method. Maximum activity and stability of trypsin were observed at 60°C and 45°C, respectively. Trypsin demonstrated maximum activity and stability at a pH value of 8.0. In general, the results of the current study suggested that trypsin extracted from the digestive system of yellowfin seabream has considerable potential for industrial applications, such as the food industry, owing to its characteristics and stability under alkaline conditions.

This study was conducted to evaluate the effects of alfalfa (Medicago sativa) extract on growth performance, feed intake, body composition and some of the serum parameters of Rainbow trout (Oncorhynchus mykiss). In this study, a total of 240 rainbow trout were weighted average 8/36±0.2(g) and randomly distributed in four treatments (control), 0.5, 1, 1.5% of extract per (kg) of diet with three replications in plastic tanks. Fish were placed and fed with extract containing food for 60 days. During this time, physicochemical factors of water were measured. At the end of the period, growth index and serum parameters calculated. The results showed that growth performance in treatments that fed with 1% alfalfa extract had a significant difference compared to control treatment (p

In this research, the effect of organic fertilizers was studied on the growth performance of carps fry. This experiment was conducted in a completely randomized design with seven treatments and three replications in 300 liters of tanks within 3 months. 60 pieces of fish fry with an average weight of 0.6 ± 0.05 g were randomly storage in each tank per 0.5: 1.5: 2: 6 (respectively, 5%, 15%, 20% and 60% respectively big head, grass carp, common carp, silver carp). Seven treatments were included control (C), vermicompost of 1 kg/m3 (T1), vermicompost fertilizer 1.5 kg/m3 (T2), compost fertilizer 1 kg/m3 (T3), compost fertilizer 1.5 kg/m3 (T4), cow manure 1 kg/m3 (T5), chicken manure 0.6 kg/m3 (T6) used in 3 replicates. Primary production, plankton and water quality parameters (temperature, chemical oxygen demand, dissolved oxygen, nitrogen-ammonium and phosphate) were measured weekly or twice weekly. At the end of the experiment period, the growth indices were measured. The results showed that the highest amount of dissolved oxygen, chlorophyll a concentration, phytoplankton and zooplankton was observed in T1 treatment and the lowest in control group (p

The main goal of the current study was to investigate the effects of low protein diets along with fishmeal replacement by plant protein in rainbow trout diet. In the current study, three protein levels (32, 36 and 40%) and three fishmeal levels (20, 40 and 60%) were tested in rainbow trout. Amino acid content of the diets were balanced by addition of essential amino acids. This led to nine experimental diets and three replicates for each treatment. The results showed that growth parameters were influenced by protein level (p0.05). Maximum growth was observed in fish fed diet containing 36% protein and 40% fishmeal. Both protein level and fishmeal replacement affected TAN excretion in rainbow trout (p

In this study, the effect of different levels of Malic acid (0.0, 2.5, 5, 7.5 and 10 g/kg diet) was evaluated on growth performance and body composition of juvenile Siberian sturgeon (Acipenser baerii). A total number of 375 fish (33.72 ± 0.60 g initial weight; mean ± S.E.) were randomly assigned to 15 circular concrete tanks (1.85 m diameter and 0.25 m depth). The fish were distributed in 5 treatments with 3 replicates and were fed during 8 weeks. The results of growth indices showed that different levels of Malic acid did not have a significant effect on growth performance and food efficiency. food consumption and lipid productive value had a significant difference among the groups (p< 0.05). The lowest amount of fat and ash contents was observed in fish fed with 7.5 g/kg Malic acid. Based on the results, the use of Malic acid in this study on juvenile Siberian sturgeon did not have an effect on growth performance, but affected on the body composition.

This study was conducted to evaluate the effects of alfalfa (Medicago sativa) extract on growth performance, feed intake, body composition and some of the serum parameters of Rainbow trout (Oncorhynchus mykiss). In this study, a total of 240 rainbow trout were weighted average 8/36±0.2(g) and randomly distributed in four treatments (control), 0.5, 1, 1.5% of extract per (kg) of diet with three replications in plastic tanks. Fish were placed and fed with extract containing food for 60 days. During this time, physicochemical factors of water were measured. At the end of the period, growth index and serum parameters calculated. The results showed that growth performance in treatments that fed with 1% alfalfa extract had a significant difference compared to control treatment (p

In this study, the effects of different dietary levels of Azolla meal were investigated on growth performance and digestibility of common carp (Cyprinus carpio) fingerlings during 60 days. Five experimental diets approximately iso-protein (30%) and iso- lipidic (10%), were formulated with different levels of Azolla meal consisting of 0, 15, 25, 35 and 45%, respectively. In each experimental treatment, triplicate groups of common Carp fingerlings (16.5± 0.2 g) were used in a completely randomized design. Twenty fish were assigned to each experimental unit and stocked in 300 L tank. The results showed that the use of Azolla meal up to 15% had no negative effect on growth performance. The growth of fish was reduced significantly with increasing Azolla meal level of more than 15% of diet. Based on results, the apparent digestibility coefficients (ADC) of dry matter decreased with increasing Azolla meal in diets. The highest ADC of protein was observed in control treatment. However, no significant difference was observed between the treatment 2 (diet with 15% Azolla meal) and control (without Azolla meal) for ADC of protein. In general, results of the present study showed that Azoll meal can be used up to 15% in Cyprinus carpio diet.

This study was carried out to evaluate the effects of dietary carbohydrate levels on growth performance and body composition of juveniles Caspian Kutum (Rutilus frisii kutum). Fish with initial average weight of 0.8±0.2g (±SD) were fed five isoproteic and isenergic formulated diets with different carbohydrate levels including 15, 20, 25, 30 and 35% in triplicate groups, 4 times daily according to their satiation for 10 weeks. Results showed that increasing the level of carbohydrate to 35% significantly increase some growth indices such as final weight (Wf), weight gain (WG), body weight increase (BWI), specific growth rate (SGR) and protein efficiency ratio (PER). In addition, result of body composition analysis showed that the increase in carbohydrate level lead to increase of protein level. So, the highest amount of protein was observed in fingerlings fed with diet containing 35% carbohydrate. In conclusion, the results indicate that increase in carbohydrate levels from 15 to 35% have not any negative effect on growth parameters and therefore, the level of 35% carbohydrate in the diet of 1-2g Caspian Kutum fingerlings can lead to better efficient in protein and desirable growth.

The industrial wastes, sewage effluents, agricultural run-off and decomposition of biological waste may cause high environmental concentration of chemicals that can interfere with the cell cycle activating the programmed process of cells death (apoptosis). In order to provide a detailed understanding of environmental pollutants-induced apoptosis, here we reviewed the current knowledge on the interactions of environmental chemicals and programmed cell death. Metals (aluminum, arsenic, cadmium, chromium, cobalt, zinc, copper, mercury and silver) as well as other chemicals including bleached kraft pulp mill effluent (BKME), persistent organic pollutants (POPs), and pesticides (organo-phosphated, organo-chlorinated, carbamates, phyretroids and biopesticides) were evaluated in relation to apoptotic pathways, heat shock proteins and metallothioneins. Although research performed over the past decades has improved our understanding of processes involved in apoptosis in fish, yet there is lack of knowledge on associations between environmental pollutants and apoptosis. Thus, this review could be useful tool to study the cytotoxic/apoptotic effects of different pollutants in fish species., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Apoptosis, a form of programmed cell death, is a critical component in maintaining homeostasis and growth in all tissues and plays a significant role in immunity and cytotoxicity. In contrast to necrosis or traumatic cell death, apoptosis is a well-controlled and vital process characterized mainly by cytoplasmic shrinkage, chromatin condensation, DNA fragmentation, membrane blebbing and apoptotic bodies. Our understanding of apoptosis is partly based on observations in invertebrates but mainly in mammals. Despite the great advantages of fish models in studying vertebrate development and diseases and the tremendous interest observed in recent years, reports on apoptosis in fish are still limited. Although apoptotic machinery is well conserved between aquatic and terrestrial organisms throughout the history of evolution, some differences exist in key components of apoptotic pathways. Core parts of apoptotic machinery in fish are virtually expressed as equivalent to the mammalian models. Some differences are, however, evident, such as the extrinsic and intrinsic pathways of apoptosis including lack of a C-terminal region in the Fas-associated protein with a death domain in fish. Aquatic species inhabit a complex and highly fluctuating environment, making these species good examples to reveal features of apoptosis that may not be easily investigated in mammals. Therefore, in order to gain a wider view on programmed cell death in fish, interactions between the main environmental factors, chemicals and apoptosis are discussed in this review. It is indicated that apoptosis can be induced in fish by exposure to environmental stressors during different stages of the fish life cycle.

This study evaluated the effects of a commercial prebiotic, Immunogen, on feed utilization, growth rate, immunity promotion and carcass composition of the common carp Cyprinus carpio fingerlings. The fingerlings were adopted for 2 weeks and then reared in triplicate groups in 250-l tanks (n = 15 per tank with average initial weights of 11.12 ± 0.55 g). The fish fed on five isonitrogenous and isoenergetic experimental diets containing different levels of Immunogen (0, 0.5, 1, 1.5 and 2.5 g prebiotic/kg diet) to apparent satiation thrice a day for 8 weeks. Weight gain showed no differences among the groups fed different Immunogen levels. Both feed efficiency ratio and protein efficiency ratio significantly (p < 0.05) increased with increasing Immunogen levels from 0.5 to 1.5 g/kg diet. The highest protein content (p < 0.05) was found in the fish fed a diet containing 2.5 g/kg prebiotic. Haematological parameters and plasma total protein concentration were also significantly higher (p < 0.05) in the fingerlings fed diets containing 1.5 and 2.5 g/kg prebiotic in relation to the control. The control fish contained the highest mean of total bacterial counts. The lowest mean (p < 0.05) of total bacterial counts was observed in the fish fed the diet containing 2.5 g/kg Immunogen. The present study reveals that a dietary Immunogen supplementation from 1 to 1.5 g/kg is capable to improve the feed efficiency and growth performance of C. carpio fingerlings as well as their resistance to A. hydrophila infection., (© 2011 Blackwell Verlag GmbH.)