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Title: Rearing screwworms: from fresh meat to artificial diet

Author
item Chaudhury, Muhammad

Submitted to: National Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/30/2013
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Research in development and continuous modification of screwworm larval diet for mass rearing is driven by various factors, including increase in cost of ingredients used, availability and supply of ingredients, amount of labor and time needed to prepare and feed the insects, and developing an environmentally safe waste management system. At the beginning, screwworm larvae were reared on lean beef mixed with bovine blood. Evolving from this lean meat-based diet, was the first artificial diet that used lean beef, citrated beef blood, milk, and water. Formalin was used in this diet as an antimicrobial agent. Later, milk was removed from the diet. Several formulations using meat originating from various animals were also tried. Due to the high cost of meat, unreliable supply, competition with pet food industries, and high expenses for storage, alternative methods were investigated. Consequently, a liquid, - so-called hydroponic diet was developed, which used dried whole chicken egg, dried whole bovine blood, a milk dry substitute, and sucrose as the dietary ingredients. This liquid diet was suspended in acetate fiber mats to provide support for the growing larvae. However, this system was found to be extremely labor-intensive. Extra time and manpower were needed to keep the rearing vat clean by removing waste media every 4 hour replacing with fresh diet. Also, high accumulation of gaseous metabolic waste from the rearing vat resulted in a poor work environment. The liquid diet was then solidified using a synthetic super-absorbent gel, a sodium polyacrylate polymer. This gelled-diet was found most suitable for mass rearing screwworms. However, because of the non-biodegradable nature of the inorganic gel, waste-disposal became a concern. Further research identified biodegradable organic cellulose fiber, which could replace the non-biodegradable inorganic polyacrylate gel. The cellulose fiber-based diet produced high quality insects and was found less expensive, besides being environmentally safe in terms of waste disposal. Future research on screwworm diet development aims at determining nutritional requirements of larvae in terms of nutrient macro and micro-molecules and bio-availability of these molecules in prepared diets.