Associative Effects of Rhodotorula glutinis Yeast x Mulberry Leaves on the Morpho-Productive Parameters of Two Breeds of Silkworms Bombyx mori L.

The nutritional value of mulberry leaves is correlated with the morpho-productive performances of silkworms B. mori. Rodotorula glutinis is an oleaginous microorganism that may produce a wide range of metabolites. There is no evidence on using this yeast to silkworm. We aimed to assess the morpho-productive performance of RG90 and Maritza III silkworm breeds fed Rodotorula glutinis. A bifactorial trial (3x2) was running on 600 larvae belonging to RG90 and Maritza III breads. The measurements were done on first, 5th, 7th, and 9th days (D) during 5th instar and after cocoon formation. Larvae were randomly distributed in 3 groups (2 replicates): 1) C group fed mulberry leaves; 2) E1 fed C diet and yeast 1x107; 3) E2 fed C diet and yeast 1x109. The larva characteristics tend to be impacted by the breed (>1.03 times higher on Maritza III. Compared to first D, a high significantly increase of larva was noticed in D9 (>1.74 times). The silk gland was positive correlated with larva length (r=0.76, P<0.0001) and larva weight (r=0.61, P<0.0001), and depend significantly of breed. The breed influence significantly certain cocoon parameters. We demonstrated that the mulberry leaves with yeast allow to silkworm to express their morpho-productive potential.