Abstract:
Selection of herbal plant extracts with prebiotic properties for growth promotion and yield enhancement of Thai hybrid silkworm. Eight herbal plant species, garlic (Allium sativum L.), basil (Ocimum tenuiflorum L.), onions (A. cepa L.), lemongrass (Cymbopogon citratus Stapf.), galangal (Alpinia galanga L.), ginger (Zingiber officinale Roscoe), turmeric (Curcuma longa L.), and bergamot (Citrus hystrix DC) were extracted with water. The 10% (w/v) concentration of the extracts were sprayed on mulberry leaves then fed to the 3 rd instar larvae silkworm and kept rearing until the worm entering pupa stage. The experimental treatments were subjected to Completely Randomized Design (CRD). The results showed that silkworms treated with basil, galanga, ginger, and turmeric extracts had a shorter period of the larval stage than other methods (18-19 days). Besides, the worms treated with turmeric extract showed the highest cocoon percentage (18.19% ), which was similar and non-statistically different (P> 0.05) to galanga extract (17.74% ). Galanga and turmeric were extracted with either water or ethyl alcohol ( 7 0 % ) at concentration of 5, 10, and 15% (w/v). With water extraction, fresh cocoon weight was higher at 5% (w/v) concentration with 0.8680 g and 0.8719 g of galanga and turmeric extracts, respectively. However, cocoon shell percentage had increased as 20.58% and 1 8 .4 3 % for galangal and turmeric extracts, respectively, at 15 % (w/v) concentration. Moreover, galanga and turmeric extracts gave the highest cocoon shell percentage as 16.68% and 15.83%, respectively, with 5% (w/v) ethyl alcohol In the testing of 15 isolates of probiotic bacteria, including Lactiplantibacillus (para)plantarum (N3 and G4), Lactiplantibacillus paraplantarum (St1, St2, and St3), Pediococcus pentosaceus (R1, R4, R5, R8, R11, and L1), and Limosilactobacillus fermentum (G3, G6, G7, and N4), when sprayed onto mulberry leaves and fed to 3rd instar silkworms, it was found that spraying with probiotic bacteria from all isolates resulted in a consistent larval duration from instar 1 to 5 of 25.05 days. L. fermentum G6 and L. paraplantarum St3 had the highest survival rates of larvae (100%), while L. fermentum G3 had the lowest survival rate (82.14%). Additionally, L. paraplantarum St3 showed a 100% cocooning rate. P. pentosaceus R1 showed the highest weight of 5th instar larvae (31.410 grams/10 larvae), followed by three isolates: GUK (31.013 grams/10 larvae), L. fermentum G6 (30.433 grams/10 larvae), and L. fermentum G3 (30.327 grams/10 larvae). In terms of cocoon yield, spraying with P. pentosaceus R11 resulted in the highest fresh cocoon weight (1.5560 grams), which was not statistically different (P>0.05) from GUK (1.5195 grams) but was statistically different (P<0.05) from the other isolates. Spraying with L. fermentum G7 led to the highest shell weight, at 25.04 centigrams, followed by L. (para)plantarum G4 (24.81 centigrams), with no statistically significant difference. However, in terms of shell percentage, L. fermentum G6 had the highest value, at 16.75%, followed by L. (para)plantarum G4 (16.69%), with no statistically significant difference. When the intestines of silkworms fed on mulberry leaves sprayed with L. paraplantarum St3, L. fermentum G7, and P. pentosaceus R11 were examined for the number of probiotic bacteria, it was found that silkworms that consumed mulberry
leaves sprayed with L. paraplantarum St3 and P. pentosaceus R11 had a high number of probiotic bacteria colonies forming clear zones around the colonies, equal to 2.4x107 CFU/mL and 9.0x106 CFU/mL, respectively