Effects of herbal products in vitro and in vivo

In the framework of a project for the Dutch Government on “Quality and safety of herbal products for production animals” the antimicrobial action of 23 products was investigated both by microbroth dilution and agar diffusion tests. Bacteria tested were Salmonella typhimurium, Staphylococcus aureus Hoechst, Pseudomonas aeruginosa, Bacillus cereus, Escherichia coli ATCC 11303, Escherichia coli “Bay” and Enterococcus faecalis. The products were tested with and without buffer, because products with a low pH may give growth inhibition which is not related to the herbs. In some products there was a marked difference between the microbroth dilution test and the agar test and also in many products there were differences between the results with and without buffer. Some products showed very good antimicrobial action whereas others did not show any activity. To examine the effects in vivo five of these products (both active and non-active, table 1) were fed to broiler chicken which were fed a nutritional sufficient diet containing a high amount of wheat which may impair digestion and gut health.

Tab. 1: Main ingredients herbal products

Product	Mean ingredients
Negative control	none
Biostrong 510	Thyme oil and star anise oil, bitter substances, pungent substances and saponins
Bronch Arom	Anise oil, thyme oil, eucalyptus oil
Allimax	Garlic
Duo Kruidenelixer	120 herbs: a.o. sage, rosemary, thyme, devils claw
PrimeFulvic	Fulvic acid

The products were compared to a control group and the trial was designed as a randomized complete block consisting of six repetitions per treatment. Data on growth, feed conversion and weight gain were collected and the jejunum was sampled for histological investigation. Villus crypt ratio was determined as an indication for gut health. Three of five herbal products showed significant differences as compared to the control group, two products with superior weight gain and one product with reduced weight gain (table 2). The two products which showed the best results in the broilers were products that showed almost no antimicrobial action in vitro. We concluded that in this experiment effects on gut health in broilers was not related to antimicrobial action.

Tab. 2: Body weight gain (BWG; g), feed intake (FI; g), and feed conversion ratio (FCR; g/g) from D0 – 35, as affected treatment.

Treatment	BWG		FI	FRC
Negative control	2547	ab	3771	1.481	a
Biostrong 510	2528	ab	3767	1.491	ab
Bronch Arom	2467	a	3734	1.514	b
Allimax	2546	ab	3758	1.476	a
Duo Kruidenelixer	2615	b	3860	1.477	a
PrimeFulvic	2578	b	3844	1.49	ab