Use of Naturally Occurring Anthelmintics to Control Parasites in Small Ruminants.

摘要

There is a critical need to identify natural anthelmintics for food animal production because of the increased resistance of intestinal parasites to commercial anthelmintics and the inability to use commercial anthelmintics for certified organic food production. Condensed tannins (CT) and flavonoids have been investigated and shown varied efficacy as natural anthelmintics. This research was done to investigate the effects of utilizing by-products of the juice and wine making industries, pomegranate husk (PH) and grape pomace (GP), which both contain these bioactive compounds of interest. An extraction was done on both by-products to determine the concentration of CT available. Pomegranate husk varieties of interest, Parifanka and Desertnyi, contained approximately 1.49 and 2.02% CT on a dry matter (DM) basis, respectively. Grape pomace varieties, Shiraz and Cabernet Sauvignon, contained 4.83 and 3.68% CT, respectively.;In vitro batch culture was conducted in a slope ratio design to determine the effects of the by-products on dry matter degradation (DMD) when compared to and mixed with a control, alfalfa hay. Both varieties of GP had lower ( P < 0.05) DMD at 96 h with greater than 70% dry matter remaining (DMR), however both varieties of PH had similar digestibilities as alfalfa with approximately 40% DMR. There was an inverse response in DMD when GP was mixed with the ground alfalfa hay; as the proportion of GP to alfalfa increased, the DMD decreased (P 0.10) on DMD in mixed ratios. Desertnyi PH was observed to have slightly better digestibility than alfalfa, and the DMD decreased with increasing alfalfa.;In vitro parasitology studies were done on stage three larvae of O. ostetagia using extracts of PH and GP. There were several varieties of PH available, so preliminary studies were done to determine two varieties showing highest efficacy on larvae to use in subsequent studies. The Sogidana and Wonderful varieties were used for the PH, and Shiraz and Cabernet Sauvignon varieties were used for GP. Overall, both PH and GP extracts had approximately twice the number of inactive larvae present (P <0.05) in the well at 24 h when compared to the control, 32 to 41% inactivity versus 17% inactivity, respectively. Grape pomace extracts had a marginally greater (P <0.05) efficacy on reducing the viability of the parasites than the pomegranate husk extracts at 24 h when observed at 12.5 mg/mL of crude extract. The PH had a higher extractability than GP was able to reach 50 mg/mL of crude extract. The Wonderful variety of PH had the highest ( P <0.05) efficacy against the parasites when compared to Sogidana at the same concentration and against the control.;Two trials were conducted for evaluating the effect of GP on mixed gastrointestinal helminth parasite infestation in growing lambs. The first trial examined the effect of a GP diet (28 g CT/kg DM) against a positive (Cydectin, no CT, normal alfalfa pellet diet) control and a negative control (no CT, normal alfalfa pellet diet). The second trial examined the effects of GP diets containing 25 (GPD1) or 45 (GPD2) g CT/kg DM against a negative control. Lambs were assessed for body weight (BW), FAMACHA(c)(anemia eye score), fecal egg count (FEC), average daily gains (ADG), packed cell volume (PCV) and feed intake (FI). In trial 1, there was an increase (P <0.05) in BW observed each week which would be expected as the lambs grew, irrespective of treatment. As the weeks progressed, the treatments varied in ADG with the Cydectin treatment group having the highest (P 0.10) between treatments but FI increased (P <0.05) weekly.;An egg hatch and larval development study was done on feces from parasitized lambs from different farming practices (organic versus conventional) in the presence or absence of GP extract (38 g CT/kg DM) to evaluate the effects of GP on egg hatchability and larval development. The GP treatment showed a 100% inhibition (P <0.05) of egg hatch into developing larvae when compared to the control distilled water treatment.;The data from the research conducted has shown that GP from the wine industry and PH have efficacy against larval helminth stages of GIP and GP also has efficacy against egg hatchability and larval development. The PH and GP could potentially have practical application in becoming a natural anthelmintic for small ruminants, but more in depth studies are needed to verify and finalize application methods. (Abstract shortened by UMI.).