Thesis (M.Sc. (Pharmacology)) -- Mahidol University, 1978. / Supported by the Faculty of Dentistry, Mahidol University and the National Research Council.

The following study was conducted to investigate the antibacterial and feed additive potential of medicinal plants. Ethanol extracts of different medicinal plants including Curcuma longa (Turmeric), Zingiber officinale (Ginger), Piper nigrum (Black Pepper), Cinnamomum cassia (Cinnamon), Thymus vulgaris (Thyme), Laurus nobilis (Bay leaf), and Syzgium aromaticum (Clove) were tested using the disc diffusion method for their antimicrobial activity against the common poultry pathogens E. coli, S. typhimurium, E. faecium, and E. faecalis. Cinnamon extract (CE), at 130 mg/disk, exhibited antibacterial activity against E. coli, S. typhimurium, and E. faecalis. Thyme extract (TE), at 30 mg/disk, exhibited antibacterial activity against E. coli, E. faecium, and E. faecalis while the remaining medicinal plants extracts showed no activity. The minimum inhibitory concentration (MIC) of the cinnamon and thyme ranged from 31.25 to 250 mg/ml by the dilution method. From this in vitro antibacterial study, cinnamon and thyme were selected for a 21-d feeding trial in broilers to study their influence on feed consumption, body weight gain, and feed conversion. There were 6 dietary treatments groups: 1) negative control (NC) containing no plant extracts or antibiotic, 2) positive control (PC) containing BMD (bacitracin) at 50g/ton of feed, 3) Diet 1 plus low level of cinnamon extract (LCE) at 290 gm/100 kg of feed, 4) Diet 1 plus high level of cinnamon extract (HCE) at 580 gm/ 100 kg of feed, 5) Diet 1 plus low level of thyme extract (LTE) at 290 gm/100kg of feed, and 6) Diet 6 plus high level of thyme extract (HTE) at 580 gm/100 kg of feed. No significant changes in body weight gain were observed with the cinnamon extracts compared to the NC or PC at 7, 14, or 21 d. The HTE reduced body weight gain compare to the NC and PC at 7, 14, and 21 d (P < 0.02). No difference in feed efficiency was observed with any of the treatments except LCE which reduced feed efficiency compared to other treatments. No difference in feed consumption was found among any of the treatments. These results suggest that cinnamon and thyme have antibacterial activity in vitro, and thyme has an activity that reduces body weight. Since cinnamon caused no significant change in body weight gain compared to positive or negative controls, it warrants further study as a substitute for antibiotics in the diet. / Master of Science

Siekiant pagerinti silosuojamų pašarų kokybę ir užtikrinti galvijų sveikatingumą, buvo ištirtas kukurūzų siloso užterštumas, siloso mėginiai paimti iš įvairių Lietuvos vietovių ir įvertintas užterštumas mikroormanizmais ir mikromicetais. Nustatytas mikromicetų jautrumas Vaistinio čiobrelio (Thymus vulgaris), Vaistinio šalavijo (Salvia officinalis) ir Paprastojo raudonėlio ( Origanum vulgare) 100% eteriniams aliejams. Užkonservavus kukurūzų siloso žaliavą laboratorinėmis sąlygomis, po 96 dienų buvo nustatytas eterinių aliejų antigrybinis ir antibakterinis veikimas minėtiems eterininiams aliejams 1:100, 1:200 koncentracijų, Vaistinio čiobrelio ir Vaistinės juozažolės, ekstraktams ir žolelėms. Nustatytos trichotecenų (T–2), deoksinivalenolo (DON), zearalenono (ZON) ir aflatoksino B1 (AFL B1), mikotoksinų koncentracijos Vaistinio čiobrelio, Vaistinės juozažolės, Vaistinio šalavijo ir Paprastojo raudonėlio eterinių aliejų 1:200 koncentracijojose. / In order to assess contamination of corn silage, it´s examples were taken from diffrent locations of Lithuania and established their contamination of microorganisms. Established the sensitivity of fungi for Thyme (Thymus vulgaris), Hyssop (Hyssopus officinalis) ), Salvia (Salvia officinalis), and Oregano (Origanum vulgare), 100% essential oils. In fermented raw corn silage on laboratory conditions after 96 days were established antibacterial and antifungal activity of essential oils in 1:100 and 1:200 concentations, Thyme and Hyssop extraxts and herbs.In mentioned essential ois 1:200 concentrations were established T–2 toksinas, deoxynivalenol ( DON) , zearalenone ( ZON ) and aflatoxin B1 ( AFL B1) mycotoxins concentrations.