Journal of The World Aquaculture Society最新文献

The present work aimed to investigate the impacts of tank color (transparent, light blue, and red), feed pellet types (floating and sinking), and their interaction on the performance and welfare of red hybrid tilapia juveniles with an initial average weight of 19.59 g for a 50 day trial period following a 3 × 2 factorial design. Fish were cultured randomly at a stoking rate of 10 juveniles/100-L tank. Fish were fed 6 days per week at a rate of 4% biomass twice daily. Three replicates were performed for each measurement. A two-way analysis of variance showed that using tanks of different colors (transparent, light blue, and red) has no impact on the growth, feed efficacy, survival rate, and blood composition (except for red blood cells, hematocrit, and triglycerides) of tilapia. Also, pellet types (floating and sinking) showed no significant alterations for the above variables except for glucose and hematocrit levels. Interestingly, the interaction between tank color and pellet type exhibited significant impacts on growth parameters, feed utilization, blood variables, and intestinal enzymes of red hybrid tilapia. Moreover, fish reared in transparent or light blue tanks and fed with floating diets performed the best for all evaluated parameters. Additionally, sinking pellets had better effects when combined with red (dark)-colored tanks.

Offshore aquaculture is a growing industry, but a lack of social acceptance is limiting development, including within the USA. We used the Gulf Coast of Florida, where there has been industry and government interest in development, as a case study to explore offshore aquaculture potential and methods for integrating stakeholder concerns into offshore aquaculture development. We assessed (1) social acceptance of offshore aquaculture in the Florida Gulf Coast using public comments; (2) site suitability for offshore development using social, biological, and technical data; and (3) potential impacts of offshore aquaculture on communities using socioeconomic vulnerability indices. We found that many stakeholders distrust policymakers and industry and have concerns about potential environmental impacts. We created species-specific suitability maps for red drum (Sciaenops ocellatus) and almaco jack (Seriola rivoliana), demonstrating that large areas of the Gulf are suitable for offshore aquaculture development. We show that many coastal and fishing-reliant communities have existing vulnerabilities that aquaculture development could affect, but the public comments did not reflect these. To gain social acceptance, industry and government agencies will need to better incorporate public feedback into planning processes in a meaningful way. Consulting local communities and adapting projects in response to their concerns can help to secure social license for offshore aquaculture.

The efficacy of dietary β-glucan supplementation in golden trevally (Gnathanodon speciosus) was evaluated. The fish were fed five different diets supplemented with 0%, 0.05%, 0.10%, 0.20%, and 0.40% β-glucan for 56 days. After 56 days of culture, survival was the highest when the fish were fed a 0.10% β-glucan diet. Growth rates were higher in fish fed diets supplemented with all β-glucan levels. Lymphocytes increased when the fish were fed a diet supplemented with 0.05% β-glucan, and thrombocytes increased when the fish were fed 0.2% and 0.4% β-glucan-supplemented diets. The total aerobic bacteria count in the gut of golden trevally was higher (p < 0.05) and the total Vibrio counts in the gut of golden trevally were lower (p < 0.05) when the fish were fed any level of β-glucan. Flesh protein content was higher and flesh lipid content was lower when fish were fed β-glucan-supplemented diets at levels greater than 0.1%. When challenged with Streptococcus iniae, fish fed diets containing 0.10% or 0.20% β-glucan exhibited the highest survival rates. The current results suggest that supplementation with 0.05 to 0.2% β-glucan in the diet would be beneficial for the culture of the golden trevally.

In this study, a biofloc technology (BFT) based 90-day feeding trial was performed to estimate the effects of four different dietary protein levels (290, 320, 350 and 380 g protein kg⁻¹ diet; 29P, 32P, 35P, and 38P, respectively) on growth performance, digestive enzyme activity, non-specific immune response, whole-body proximate and fatty acid composition and intestinal microbiota of Farfantepenaeus aztecus. Final weight, weight gain, and specific growth rate improved with protein levels up to 35P per kg of diet, below which decreased significantly. Significant differences were observed in total hemocyte count, acid phosphatase, respiratory burst, glutathione, alkaline phosphatase, and total antioxidant capacity indices of shrimp fed different dietary protein levels. Protease, lipase, and amylase activities of shrimp were also affected by dietary protein levels. Proteobacteria was the most abundant bacteria among the groups. Overall, this study revealed that using 35% dietary protein is optimal in F. aztecus culture under environmentally friendly BFT conditions. Furthermore, these results provide a theoretical basis for future research on the evaluation of functional ingredients in diet for more economical production of F. aztecus at optimal protein levels.

Although hybrid catfish (Ictalurus punctatus × I. furcatus) now constitute about half of the industry production, few studies have assessed comparative growth and survival with other commercially important catfish. Growth assessment is particularly important at moderate to high temperatures because of the direct influence of temperature on ectothermic organisms and the increasing trend of warm to extreme environmental temperatures. Therefore, growth, condition factor, and survival of channel (I. punctatus), blue (I. furcatus), and hybrid catfish were compared following a 10-week growth experiment at moderate (23°C) and high (33°C) temperatures in tanks. It was hypothesized that hybrid catfish would outperform channel and blue catfish in overall growth due of heterosis, and growth of all three fish types would be greater at moderate than high temperatures, which are above the range for optimal channel and blue catfish growth. Channel catfish had the greatest growth and were in better condition compared to blue and hybrid catfish over moderate and high temperatures. All treatments had an average survival over 89% other than blue catfish at 33°C, which had an average survival of 63%. Therefore, these results indicate growth and condition factor in channel, blue, and hybrid catfish diminish at high temperatures, and channel catfish may outgrow blue and hybrid catfish at moderate to high temperatures.

Growth selection in fish is essential for aquaculture; however, long generation times and artificial breeding limitations present challenges for breeding endeavors. The tomato grouper (Cephalopholis sonnerati) is an emerging aquaculture species with a generation cycle of at least 5 to 10 years. Mixed culture of broodstocks and natural mating are commonly employed in hatcheries. To expedite the selection process for tomato grouper, we utilized ISSRseq technology for assisted future growth selection. After 6 months of rearing, we selected 48 individuals, including 24 fast-growing and 24 slow-growing individuals (representing the top and bottom 10% of samples). These samples produced 932 SNPs. Although specific broodstock pairing information is unavailable, our results suggest that these fry likely originated from multiple broodstock exhibiting considerable diversity. Further analysis of genetic relationships among individuals revealed three main clades. One clade contained a higher proportion of faster-growing individuals (80%), while another featured a lower proportion of rapidly growing individuals (28.6%). Through the relatedness network and further exclusion of individuals, the faster-growth clade comprised 92.3% of fast-growing individuals. The faster-growth clade is appropriate for further development into a high-growth strain. Our findings demonstrate that molecular markers can advance population selective breeding to family selection in aquaculture breeding research.

This study was designed to explore the dietary effects of Capsicum annuum oleoresin (CAO) on growth, body composition, sensory characteristics, gut microbiome, and intestinal histomorphometry of rainbow trout. Fish (195.13 ± 1.55 g) were fed diets with various CAO levels (0.0-Control, 7.0- g kg ⁻¹ C7, 14.0 g kg ⁻¹ -C14, 21.0 g kg ⁻¹-C21, and 28.0 g kg ⁻¹-C28) for a 30-day period. Results revealed that the maximum growth was achieved in C7 and C14 groups. Nevertheless, the growth parameters were similar in other groups compared to the control. Moreover, there were significant increases in dry matter and crude lipid contents in all CAO groups compared with the controls. The mean abundances (%) of the prevalent bacteria at the genus level in the intestinal trout samples presented no significant changes among the test groups. Dietary CAO significantly changed the intestinal histological structure, and was manifested by an increased number of goblet cells in the CAO-supplied groups. However, there were intestinal villus epithelial deformations associated with increasing dietary CAO, and were most prominent in the C28 group. The sensory attributes of cooked trout fillets showed that capsicum's pungent odor and taste was evident in the C14 group and subsequently increased with increasing dietary CAO levels. Accordingly, the results showed, for the first time, that dietary CAO at levels (7–14 g kg⁻¹) can enhance the growth of rainbow trout without negative effects on the sensory characters and gut health.

Most studies evaluating the use of distiller's dried grains with solubles (DDGS) to partially replace the use of soybean meal (SBM) in diets of shrimp Litopenaeus vannamei have been carried out under laboratory conditions, which has significant differences in terms of environmental and culture conditions with the out-door commercial pond. This study aims to extrapolate the laboratory trials into the out-door pond condition in order to evaluate the feasibility of incorporating DDGS at various levels (D0 (0%), D5 (5%), D10 (10%), and D 15 (15%)) to replace the use of SBM for 90-day culture period on the growth, body composition, total hemocyte count, lysozyme activity, and organoleptic characteristics of the shrimp. Seven hundred twenty shrimp (mean initial weight 1.06 ± 0.01 g) were randomly distributed into each of 40 net pens (3 × 2 × 1 per net pen) with 10 replicates per dietary treatment. The results showed an enhancement in biomass, mean weight, and thermal growth coefficient of shrimp fed with 5 and 10% inclusion levels of DDGS. Significant reduction of FCR was also observed with the use of 5 and 10% DDGS to partially replace SBM. There were no severe changes in the total hemocyte count (THC), lysozyme activity, color, aroma, and flavor of the shrimp. However, the texture of shrimp was significantly better with the use of 10 and 15% DDGS in the diet. In summary, regarding all the factors, DDGS is a promising alternative ingredient to replace the use of SBM with 5 and 10% inclusion levels and could modulate better growth, quality, and maintain the health condition of shrimp cultured in out-door pond conditions.

In order to screen out the feeding ratio of high-quality algae strains in Hyriopsis cumingii, this experiment investigated the effects of different ratio of mixed feeding of two algae strains (Scenedesmus dimorphus and Cyclotella sp.) on the growth, bead production performance, trace elements, and amino acid composition of the newborn shell of H. cumingii. The results showed that the mixed feeding of two types of microalgae with different densities had significant effects on the growth performance, bead production quality, trace elements, and amino acid composition of the newly formed shell of H. cumingii (p < 0.05); the best body weight gain rate and shell growth rate were obtained by feeding S. dimorphus (30 × 10⁵ cell/mL) and Cyclopella sp.(8 × 10⁵ cell/mL); the pearl weight gain rate, amino acid ratio, Ca²⁺ and Mn²⁺ content were best when feeding Cyclotella sp. (16 × 10⁵ cell/mL), but there was no significant difference compared with S. dimorphus (30 × 10⁵ cell/mL) and Cyclopella sp.(8 × 10⁵ cell/mL). In summary, the optimal feeding amount for the intensive breeding process of H. cumingii is S. dimorphus (30 × 10⁵ cell/mL) and Cyclopella sp. (8 × 10⁵ cell/mL).

The dietary protein levels and source of starch are factors in the economical production of feeds, which may change the physical quality of extruded pellets and the growth performance of fish. Eight feeds contained two protein levels and four levels of wheat flour substitutions by corn, as a 2 × 4 factorial experimental design, were produced by a twin-screw extruder machine and fed to 800 rainbow trout. The results showed corn grain reduced expansion ratio, water stability at 120 and 260 min, starch gelatinization (SG), and apparent degradability, while bulk density (BD) and oil leakage of feed pellets increased. The high protein diets displayed the most BD, lower oil leakage, SG, and elastic modulus. The high protein feeds improved the final body weight, weight gain, specific growth rate, and feed conversion ratio (FCR) of fish. The corn grain reduced the FCR and promoted the trout's protein efficiency ratio. Lipid proportions of fish livers corresponded to hepatosomatic index and serum concentrations of aspartate aminotransferase and alanine aminotransferase. In general, corn, as the starch source in the high and low-protein extruded feeds, can be replaced at levels of 33%–66% of wheat flour without adverse effects on the physical characteristics of feed pellets and the growth performance of rainbow trout.