The Effect of Strain and Rearing Medium on the Chemical Composition, Fatty Acid Profile and Carotenoid Content in Silkworm (Bombyx mori) Pupae

Abstract

The overexploitation of fishmeal and soy for the feedstuff industry has provided an opportunity to employ insects as an unconventional and more environmental friendly protein source. The evaluation of the nutritive properties of different insect species has consequently become a priority. The present study compares the pupal nutritive composition of two silkworm strains (White Cocoon Polyhybrid and Golden Yellow Cocoon Nistari) fed on two different rearing media (fresh mulberry leaves and a commercial artificial diet). Our results provide evidence that the composition of the feeding substrate strongly influences the fat and protein content of silkworm pupae. The two tested strains had higher fat and lower protein contents when fed with silkworm natural food (mulberry leaves) with respect to the commercial artificial diet. The analysis also showed that the n3/n6 ratio was affected almost exclusively by the feed substrate factor. On the contrary, the carotenoid content in pupae was specifically determined by the strain. The study identifies the interesting opportunity offered by silkworm pupae, which are usually a waste product of the silk-reeling process, to be used as alternative animal protein sources in a fully-closed circular production.

Effect of Thermal Processing on Physico-Chemical and Antioxidant Properties in Mulberry Silkworm (Bombyx mori L.) Powder

“…In this study, FASS contained 20.64% DM basis of fat content, which falls in the range of 18.9-36%, as reported by Kim et al [32]. Meanwhile, Chieco et al [33] mentioned that the silkworm contains essential fatty acids (EFA), mainly in the form of polyunsaturated fatty acids (PUFA). In addition, the silkworms also possess a higher n-3 to n-6 fatty acid ratio, which differs from other insects.…”

Mechanical Processing of Hermetia illucens Larvae and Bombyx mori Pupae Produces Oils with Antimicrobial Activity

“…It is well-known that the insect species, the rearing substrate, and the extraction method have a great influence on the quantity and quality of the oil yield. The two insects selected for our study, although taxonomically different, have some similarities that facilitate a comparison: (1) they can be used in circular economy settings giving place to considerable economic outputs; (2) they can be reared on vegetable substrates, therefore their oil profile can be mostly composed of unsaturated fatty acids with very interesting properties, as shown in the present work ( Supplementary Material—Tables S1 and S3 ); (3) their rearing substrate can be modulated and enriched; in fact, different feeds have been tested for BSFL [ 10 , 19 , 20 ] and several artificial diets, with different compositions, were studied for the silkworm [ 21 , 22 , 23 ]; furthermore, different diet regimens affect the fatty acid composition of the two insects [ 24 , 25 ]; and (4) it has already been demonstrated they are rich of antimicrobial peptides and other compounds with pharmacological action [ 2 , 3 , 26 ].…”

Nutritional value of insects and ways to manipulate their composition

“…High levels of carotenoids, including those that can be converted to retinal, are found in various wild insect species (Arnold et al, 2010;Cerda et al, 2001;Eeva et al, 2010;Isaksson and Andersson, 2007;Newbrey et al, 2013;Seki et al, 1998;Ssepuuya et al, 2017) whereas commercially produced insects contain far lower quantities (Finke, 2002(Finke, , 2013(Finke, , 2015aOonincx and Van der Poel, 2011). This difference is likely a result of dietary carotenoid intake as was shown for both silkworm larvae (Chieco et al, 2019) and fruit flies (Giovannucci and Stephenson, 1999).…”