83602 research outputs found
Sort by
Effects of Mn2+ and flow speed on blood and physiological indexes of larvae GIFT tilapia (Oreochromis niloticus)
Get PDFTo assess the toxicological effects of heavy metal ions on fish at different flowing speeds within aquatic environments, we investigated the impact of Mn^2+^ and flow speed on the physiological parameters of juvenile GIFT tilapia (95.2±4.3g,15.1±0.21cm). The experiment design included four different levels of Mn^2+^ concentration: control group (0mg/L), 0.1mg/L, 0.5mg/L and 1mg/L, as well as three different flow speeds: control group (0 body length/second), low speed (1 body length/second), and high-speed group (2 body lengths/second). The main research findings were as follows: Mn^2+^ had varying effects on the hematological parameters of juvenile GIFT tilapia. As the levels of Mn^2+^ increased, there was a remarkable reduction in both the red blood cell (RBC) number and hemoglobin content of the fish(*P*\0.05). Its effect on the fish antioxidant parameters also showed a certain induction, and there were significant correlations between the activity of SOD, CAT, the level of MDA, and flow speed (*P*\0.05). These findings could provide fundamental data for investigating the influence of heavy metal stress on fish ecotoxicology in aquatic environments and the artificial running water breeding of GIFT tilapia in Hebei province, China
Territorial Whiteness on Display: Nathaniel Emerson’s Hawaiʻi Exhibit at the Alaska-Yukon-Pacific Exposition of 1909
No full textSubstituting fishmeal with extruded cull chickpea meal in diets for the white leg shrimp (<em>Litopenaeus vannamei</em>, Boone): A preliminary study of the effect on production parameters
Get PDFAmong the most typical feed ingredients for shrimp, plants represent a low-cost source in substituting for traditional high-cost feed ingredients. Extrusion is a common grains processing technique to make plant nutrients available and more digestible to animal. Different levels (15, 30, 45, and 60%) of extruded low-quality chickpea meal were included in a formulated diet for the juvenile shrimp Litopenaeus vannamei cultured in a closed system for 75 days. The growth of shrimp fed with the tested diets was similar to the control group (P > 0.05). We concluded that the use of extruded cull chickpea meal is a potential food alternative to replace fishmeal effectively in diets for L. vannamei
The use of sesame oil in sea bream feeds and its effects on growth and body chemical composition
Get PDFAs fish oil availability declines worldwide and its price rises, there is a growing need to engage in scientific investigations into alternative oil sources for incorporation into fish feeds. This study aimed to determine the effects of dietary sesame oil on the growth performance, feed utilization, and nutritional composition of sea bream (*Sparus aurata*). Twenty-five individual fish (initial mean weight: 32.38±0.27 g) were placed in each tank in triplicate. Four experimental fish meal-based (iso-proteic 49% and iso-lipidic 20%) diets were formulated; the control (C) group contains 100% of fish oil (FO) and varying amounts (20, 40, 60%) of sesame oil (SO). During the 75-day experiment, the fish were fed 3 times a day, and the mean ambient temperature and dissolved oxygen values were measured as 22.5±0.5°C and 6.8±0.3 mg/L, respectively. At the beginning of the experiment, 20 fish were sampled to determine their nutrient composition and somatic indexes. In the end, 4 fish were collected for the same procedures and 4 for each tank's muscle and liver fatty acid compositions. At the end of the study, the S60 group exhibited the lowest final weight (FW) and feed utilization parameters. On the other hand, there were no statistical differences between FO, SO20, and SO40 in terms of FW. In addition, the SO40 group had the best feed conversion ratio (FCR) among the groups (P\<0.05). The whole-body lipid compositions of the groups were different. The highest lipid level was found in SO40 with 15.83±0.36%. Muscle and liver fatty acid composition was significantly affected by the fatty acid profile of experimental feeds. While total ω-6 fatty acids were higher in the SO groups than in group C, total ω-3 fatty acids were higher in the C group compared to the SO groups (P\<0.05). The ω-3/ω-6 ratios in the SO20 and SO40 groups showed similarity, while the highest ratio was observed in the control group (P\<0.05). As a result, according to data obtained from our study, it is predicted that 40% SO could be added to sea bream feed instead of FO in terms of growth performance, feed utilization, and nutritional composition
In Memoriam: Gérard Diffloth (1939-2023)
Get PDFThis is an "In Memoriam" for Gérard Diffloth (1939-2023)
Effects of biofloc technology on water quality and growth performance of <em>Macrobrachium rosenbergii</em>
Get PDFThis study aimed to evaluate the effects of biofloc technology on the water quality and growth performance of *Macrobrachium rosenbergii*. The experiment was carried out over 165 days at the hatchery complex of the College of Fisheries and Aquatic Sciences, Mindanao State University-Marawi, Philippines. Postlarvae of *M. rosenbergii* (0.011±0.05 g) were stocked in 18 circular tanks (1200 L) consisting of six treatments under biofloc and non-biofloc systems in a completely randomized experimental design with tapioca flour as the carbohydrate source. Commercial pelletized sinking prawn feed with three dietary protein levels, viz., 42, 38, and 35% were chosen as experimental feeds. Results of the present study show that the water parameters were within the optimum range required in the culture of freshwater prawns. However, biofloc technology (BFT) did not influence sediment and water samples' dissolved oxygen, temperature, and pH values. On the other hand, total ammoniacal nitrogen (TAN) and nitrate showed significant variation (*p*\<0.05) among treatments, with higher values in the control treatment compared to the biofloc treatments. Moreover, the dietary protein level and carbohydrate addition had no significant effect on soil pH and organic carbon except for the soil total nitrogen value, where higher values were observed in the biofloc treatments. Furthermore, significantly higher mean prawn weight gain, net prawn yield, specific growth rate (SGR), and average daily weight gain (ADG) were recorded in the biofloc treatments compared to non-biofloc treatments. At the end of the culture period, there was 100% survival in all of the tanks. On the other hand, no significant variations were observed in feed conversion ratio (FCR) and protein efficiency ratio (PER) in the control treatment compared to the treatment with biofloc except in tanks using feed of 42% CP under the biofloc system. Therefore, based on the results of the present study, the use of BFT in the culture system of *M. rosenbergii*, helped reduce the protein percentage from 42 to 35, while maintaining the yield
Dietary plant soot supplementation improves the intestinal health status of farmed American eels (<em>Anguilla rostrata</em>)
Get PDFThe current study evaluated the effect of different dietary plant soot supplementation levels on the intestinal health status of American eels (Anguilla rostrata) cultured in concrete tanks. Nine concrete fish tanks were randomly divided into three groups and fed the diets with plant soot (PS) supplementation levels at 0, 3 g/kg, and 5 g/kg, respectively. After a feeding trial for 60 days, the intestinal tissues were sampled to measure health status parameters. The D-lactate level and DAO activity in the serum of the PS5 group were significantly lower than those of the PS0 group (P <0.05). Compared with the PS0 group, the villi length of the intestine in both PS3 group and PS5 group increased significantly (P<0.05). The muscular thickness of the intestine of the PS5 group was significantly higher than the PS0 group (P<0.05). The microvillus density of the intestine of the American eel was increased obviously in the PS5 group. The intestinal microbiota composition of plant soot groups was beneficially regulated with certain probiotics' higher relative abundances and some pathogenic bacteria' lower relative abundance. In conclusion, dietary 5 g/kg plant soot supplementation could benefit the intestinal health of farmed American eels
Transcriptome analysis of <em>Litopenaeus vannamei</em> during the early stage of limb regeneration process
Get PDFRegeneration is a process in which organisms regrow new tissues or organs at the injury site, which has attracted the attention of many scientists and nonscientists. However, the underlying molecular mechanisms of regeneration after autotomy are largely unknown. In this study, we conducted RNA-seq sequencing on regenerated limb bud tissues of *Litopenaeus vannamei* at 0 hours post autotomy (0 hpa), 12 hours post autotomy (12 hpa), and 24 hours post autotomy (24 hpa). A total of 2,192 differentially expressed genes related to energy metabolism, transcription and translation, and epidermis development were identified between 0 hpa and 12 hpa, such as triosephosphate isomerase A, triosephosphate isomerase B, and zinc finger protein 367 that is upregulated in 12 hpa. Between 12 hpa and 24 hpa, 1,447 differentially expressed genes were identified that were related to cuticle development and energy metabolism, such as cuticle protein 6, which is upregulated in 24 hpa, and triosephosphate isomerase is downregulated in 24 hpa. The results indicated that energy metabolism, transcription and translation, epidermal formation, and chitin metabolism processes are involved during the early stage of limb regeneration. This study provides basic knowledge for investigating the molecular mechanisms associated with limb regeneration in crustaceans at the early regeneration stage