Social support literature has been criticized for lacking methodological clarity. The purpose of this study was to conduct a systematic descriptive review of the social support literature, outline measurement problems, identify the nature of assessment inadequacies, and provide recommendations for the future. Two‐hundred sixty‐two empirically based articles published between 1980 and 1987 were reviewed comprehensively. Information about social support measurement and sample characteristics was obtained. A system was designed to organize the data on sample characteristics, type of instrument, source of support assessed, and category of support measured. The social support literature also was described from a methodological perspective, and several trends were identified. Conclusions about conceptual maturity, a priori biases, measurement of network utilization, and social support sources are discussed.

The purpose of this study was to examine the effects of four feed‐management techniques on the production of Pacific white shrimp, Litopenaeus vannamei, using a 16‐wk trial performed in 16, 0.1‐ha ponds stocked at 17 shrimp/m2. Four treatments were used for this study: standard feeding protocol (SFP) fed twice daily, a 15% increase to the SFP fed twice daily, timer feeders programmed to feed six times daily following the SFP, and ad libitum using the AQ1 acoustic demand feeding system. Significant increases in final weights were seen using the timer and acoustic feeders (28.66 and 35.91 g, respectively) when compared with the SFP and SFP + 15% (23.55 and 24.65 g, respectively). The AQ1 treatment also resulted in a significantly higher shrimp value ($21,198/ha) than the other treatments ($11,776–$13,446/ha). No significant differences were seen in survival (72.2 ± 5.99%), feed conversion ratio (1.03 ± 0.095), or water quality. These results demonstrate that increasing the feed by 15% when feeding twice daily gives no advantage to production. Increasing the feedings from two to six times per day did improve growth and economic returns, and using acoustic feedback to feed based on feeding activity can further improve production and economic returns.

The complete genome of the channel catfish, Ictalurus punctatus, has been sequenced, leading to greater opportunities for studying channel catfish gene function. Gene knockout has been used to study these gene functions in vivo. The clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (CRISPR/Cas9) system is a powerful tool used to edit genomic DNA sequences to alter gene function. While the traditional approach has been to introduce CRISPR/Cas9 mRNA into the single cell embryos through microinjection, this can be a slow and inefficient process in catfish. Here, a detailed protocol for microinjection of channel catfish embryos with CRISPR/Cas9 protein is described. Briefly, eggs and sperm were collected and then artificial fertilization performed. Fertilized eggs were transferred to a Petri dish containing Holtfreter's solution. Injection volume was calibrated and then guide RNAs/Cas9 targeting the toll/interleukin 1 receptor domain-containing adapter molecule (TICAM 1) gene and rhamnose binding lectin (RBL) gene were microinjected into the yolk of one-cell embryos. The gene knockout was successful as indels were confirmed by DNA sequencing. The predicted protein sequence alterations due to these mutations included frameshift and truncated protein due to premature stop codons.

The effect of chemical pretreatments on the color and carotenoid content of yellow discolored channel catfish fillets was studied. The color and carotenoid content of the fillets were analyzed by the L*a*b* color system and high-performance liquid chromatography, respectively. Untreated fillets turned more yellow and darker after 12-d storage. Sodium bicarbonate had a beneficial effect on reducing the degree of yellowness, but the fillets still turned darker after storage. Sodium bisulfite gave the best results with fillets becoming less yellow and brighter after storage. Ascorbic acid, butylated hydroxyanisole, citric acid, and sodium metabisulfite were not successful at reducing the discoloration. The sum of carotenoid contents of untreated fillets decreased significantly (P< 0.05) during storage as compared to the fresh fillets. However, the sum of the carotenoid contents of fillets treated by various chemicals was not significantly (P > 0.05) different from the fresh or untreated fillets. The appearance of catfish fillets may be improved during storage by pretreating with sodium bisulfite.

No abstract

Aquaponics is an agricultural practice incorporating aquaculture and hydroponic principles. This study assesses the current system design and production practices of the aquaponic industry, compares these metrics by stakeholder group, identifies trends, and provides recommendations for future development. An electronic survey of aquaponic stakeholders was conducted from December 2019 to June 2020 targeting hobbyists, producers, and educators from various aquaponic-focused professional associations, email and social media groups. Of 378 total responses, 84% came from the United States and were clustered in plant hardiness zones five to nine. Aquaponic systems were commonly homemade/do-it-yourself (DIY), many of which incorporated commercially available (turn-key) technology. Most growers used coupled systems that integrated recirculating aquaculture systems and either deep-water culture (DWC) or media bed hydroponic units. Common plant lighting sources were sunlight and light emitting diode (LED). Water sources were typically municipal or wells. Personal labor input was typically less than 20 hrs/wk. Funding sources were primarily personal funds, followed by government grants, and private investor funds. System sizes varied greatly, but the median area was 50 to 500 ft2 for hobbyists and educators and 500 to 3,000 ft2 for producers. Respondents commonly sold vegetable produce, training and education, food fish, and microgreens. Tilapia and ornamental fish were commonly grown, with 16 other species reported. Common crops were lettuce, leafy greens, basil, tomatoes, peppers, and herbs with many additional lesser-grown crops reported, including cannabis. Overall, the industry still growing, with a large portion of stakeholders having less than two years of experience. However, veteran growers have remained in operation, particularly in the producer and educator groups. The survey results suggest a shift away from outdoor systems, media beds, tomatoes, ornamental fish, and perch production, and a shift toward decoupled systems, DWC, drip irrigation, and wicking beds, larger system area, leafy greens, and trout/salmon production compared to previous industry surveys. The reduced diversity of plant species grown suggest some level of crop standardization. Commercial producers tended to sell more types of products than other stakeholders, suggesting that diversification of offerings may be key to profitability. The combined production area specified by respondents indicates the industry has grown substantially in recent years. Finally, the presence of bank loan-funded operations suggests increased knowledge and comfort with aquaponics among lenders.

No abstract

No abstract