In vivo testing of alternatives for conventional treatment of Ascaris suum in pigs

Abstract

Summary The percentage of disapproved livers of growing and finishing pigs has been increased significantly during the last years. In organic pig farms, this percentage is often higher than in conventional pig farms. In most cases, disapproved livers are the result of an infection with Ascaris suum. Usually, an infection of Ascaris suum is treated or controlled by using conventional synthetic drugs belonging to the benzimidazoles, levamisole and macrocyclic lactones. Organic farmers, however, prefer a non-pharmaceutical approach of worm control. Therefore, phytotherapy could be an perspective alternative. The objective of this study was to test herb alternatives for the prevention and control of a mild infection of Ascaris suum in growing and finishing pigs. Two different herb mixtures were tested. Feed was supplemented with 3% of a herb mixture, thereby adding 1% Thymus vulgaris, 1% Melissa officinalis and 1% Echinacea purpurea to the diet, or with 4% of a herb mixture, thereby adding the mentioned herbs plus 1% Camellia sinensis (black tea) to the diet. Pigs were infected by 1000 worm eggs each. Comparatively, a negative control group (no treatment) and a positive control group (treatment with conventional synthetic drug Flubendazole) were included. An experiment was conducted with 32 young boars (average starter weight was 24 kg) purchased from a SPF-pig farm. The pigs were monitored during 67 days in the period December 2006 until February 2007. In this study, four experimental treatments were compared: 1. negative control: no treatment was applied to prevent or control an infection with Ascaris suum; 2. positive control: pigs were treated with a conventional anthelmintic (Flubendazole) one week before slaughter; 3. herb mixture: pigs were fed a diet supplemented with a herb mixture; 4. herb mixture + tea: pigs were fed a diet supplemented with a herb mixture (as treatment 3) plus black tea. From this experiment it was concluded that a diet with a herb mixture containing 1% Thymus vulgaris, 1% Melissa officinalis and 1% Echinacea purpurea for growing and finishing pigs did not decrease the number of pigs which are infected with Ascaris suum, but did reduce the average number of worms in the gastro intestinal tract. The addition of 1% black tea to this herb mixture did not result in a lower number of infected pigs and also did not reduce the average number of worms in pigs. Flubendazole appeared to be an effective deworming product. On organic farms with a low worm infection probably a combination of a conventional synthetic drug and a diet with herb mixture containing 1% Thymus vulgaris, 1% Melissa officinalis and 1% Echinacea purpurea is an option. It depends on the level of worm infection whether it is an opportunity to deworm sows, weaners and/or growing finishing pigs with a diet containing the herb mixture to keep the level of Ascaris suum at an acceptable low level. Examination of faeces of sows, weaners and growing and finishing pigs regularly, and also the percentage of disapproved livers of growing and finishing pigs, can support to monitor the level of worm infection on the farm. Based on this monitoring probably a strategy of varying deworming with a synthetic drug and a diet with herb mixture can be developed for the different categories of pigs. Further research on this method, and also the suitable period to supply this herb mixture to sows related to stage of pregnancy and weaners related to age and feed intake, is desirable