Dietary cinnamon supplementation has several bioactive compounds with growth-promoting and immunomodulation potential, which is suggested for finfish species. This study evaluated the inclusion of cinnamon at 0, 1, 3, 6, and 12 g/kg diet in Oncorhynchus mykiss fingerlings. After eight weeks, the best growth performance, and feed utilization parameters were calculated in fish treated with 12 g/kg (P < 0.05). Further, the white blood cells and lymphocyte levels were significantly increased and Neutrophil was significantly decreased in fish fed cinnamon at 12 g/kg compared to those fed 0-6 g/kg (P < 0.05). After the feeding trial, in the studied immune and biochemical indices, immunoglobulin ROS, Lysozyme was significantly increased (P<0.05), and Glucose decreased significantly (P < 0.05) in fish treated with cinnamon at 12 g/kg compared to fish fed 0-6 g/kg. Moreover, treated fish with cinnamon had higher levels of C3, C4, total protein and Albumin than the control with the highest value in fish treated with 12 g/kg. The results showed the positive influence of the inclusion of cinnamon in the diets for rainbow trout fingerlings on the growth performance, feed utilization, blood analysis, and immune functions. According to the results, it can be concluded that 12 g cinnamon powder per kg diet is suggested with no adverse effects to improve growth performance, feed utilization and health status in rainbow trout fingerlings.
The present study evaluated the influence of acidic polysaccharide extracted from Sargassum polycystum (SAPE) on growth, immunological responses and resistance to Vibrio harveyi infection of juvenile Penaeus monodon. Five experimental diets supplemented with 100, 500, 1000 and 1500 mg/kg SAPE including a control (0 mg/kg) were formulated and fed to juvenile P. monodon for 50 days. Following the feeding trial growth indices including weight gain and specific growth rate were significantly enhanced, (P < 0.05), in treatment groups fed with diets containing 2000 mg/kg SAPE. Highest survival (46.67 +/- 11.54%, P < 0.05) following the infection challenge test with the pathogenic V. harveyi was observed in the treatment group receiving the 2000 mg/kg SAPE supplementation while all shrimp died in the group receiving the control diet. The enhanced resistance to bacterial infection of SAPE treatment groups was further supported by improved immune responses (P < 0.05) including total hemocyte counts and serum antibacterial activities. The present study indicates that dietary supplementation of acidic polysaccharide extracted from Sargassum polycystum at a dose of 2000 mg/kg could enhance growth performance, elevate immune responses and significantly improve resistance of juvenile P. monodon against V. harveyi infection.
Tilapia is one of the most cultured fish species globally and over the last two decades, its culture has been intensified. However, water quality management in tilapia pond culture is a major barrier for higher productivity. This study assessed the water quality dynamics in 150 m(3) earthen ponds with or without fish over a period of 12 weeks. The two treatments were ponds stocked with fish (fed ponds) and ponds with water but no fish (control pond). The fed ponds comprised two ponds stocked with all-male Nile tilapia (Oreochromis niloticus) sub-adults (Mean mass similar to 40g) fed twice daily with a commercial feed (30% crude protein) while two other ponds were assigned as control. Physicochemical, biological water quality variables as well as nutrients were monitored in all ponds every four days over the 12 weeks. Dissolved oxygen (DO), pH, temperature and conductivity levels were measured in-situ between 7.00 and 8.00 a.m., while water samples were analysed in the laboratory for turbidity, total suspended solids (TSS), total dissolved solids (TDS), alkalinity, ammonia (NH3), nitrite (NO2), nitrate (NO3), ortho-phosphate, biological and chemical oxygen demand (BOD & COD), organic matter (OM) and organic carbon (OC). Additionally, a 24h DO monitoring as well as sludge accumulation and sludge characteristics were determined every three weeks in the experimental ponds. Mean DO levels over the trial duration was 42% lower in the fed ponds. The increased nutrient loadings from the fish and the supplementary feed presumably increased all biological WQ parameters measured which resulted in a higher sludge accumulated in the fed ponds. The fed ponds consistently recorded pre-sunrise DO levels of <1 mgL(-1) while the control ponds recorded DO levels >2 mgL(-1) during the same period. Generally, the results of the study showed deterioration of water quality was more evident in the fed ponds.
Microalgae are a sustainable food source for humans and aquatic organisms, and this study explores their nutritional and physiological importance. Marine and freshwater microalgae exist as microscopic photosynthetic organisms. In aquaculture, microalgae are used as food and as live feed for bivalve mollusks, juvenile stages of abalone, crustaceans and some fish species and as zooplankton in food chains. Using microalgae for food and aquatic feed is a sustainable and economically beneficial process. As a source of protein, omega-3, fatty acids and carotenoids, microalgae are more nutrient-dense than traditional forms of animal and aquatic feed, such as millet, grams and other small fish. In addition to being nutritious, they contain antioxidants, antimicrobials and disease-preventative molecules, extending the lifespan of humans and fish.
In the present study, we aimed to identify Saprolegnia spp. from infected rainbow trout eggs in a hatchery in the north (Mazandaran province) of Iran. Morphological identification was conducted by light microscopic observation of various life stages of Saprolegnia. For the molecular characterization, the internal transcribed spacer (ITS) region was amplified by using universal primers ITS 1 and ITS 4. Based on morphological and molecular findings, two Saprolegnia spp. have been identified. i.e., Saprolegnia parasitica (Isolate KMG3, MW819780) and S. salmonis (Isolates KMG1, MW819740 and KMG2, MW819707). It is worth mentioning that the latter - S. salmonis - is the first report in Iran. The phylogenetic tree inferred by a Neighbor-Joining model revealed that three representative isolates with a well-supported value together with the known isolates of S. parasitica and S. salmonis formed a well-defined clade. An in vitro experiment was conducted to study the growth of S. salmonis (KMG2) and S. parasitica (KMG3) at various incubation temperatures. Both species showed similar hyphal growth rates at 10 and 18 degrees C after 3 days of incubation (P > 0.05).
