diarrhoea in piglets and wet litter in poultry. Wet litter caus- es footpad dermatitis, hock burn and breast irritation in broilers. These symptoms lead to a decrease in performance and reduced usability of the carcass. The intestinal tract – even within its physiological range – is subject to constant irritation. Microbial contamination of the feed or drinking water, feed structure, feed composi- tion – and the intestine reacts to all these factors with an immune response and inflammation. All these processes – regardless of the cause – represent an expenditure of energy. The subtherapeutic use of antibiotics as growth promoters (AGP) has been practised for decades to im- prove performance. AGPs not only have antimicrobial effects but also anti-inflammatory properties. The ban on AGPs opened up space for natural alternatives which also have the capacity to stabilise the intestinal flora and have anti-inflammatory effects.

Wood lignans as natural AGP alternative A trial with a total of 416 male broilers (Cobb 500) compared the effects of a wood lignan product (agromed ROI) to either a negative control (NC) or a positive control (PC) with the commonly used AGP Virginiamycin in a corn/soybean diet. The wood lignans showed a significant positive influence on performance data in terms of weight gain, feed conversion, carcass and breast muscle percentage. Positive effects were also recorded for some intestinal health parameters. Villus height in the ileum increased significantly in the lignan groups and consequently also the mucosal sur- face available for nutrient absorption. The lymphocyte count was reduced in the experimental groups, indicating a re- duced need for immune defence and thus a healthier gut flora. This thesis was also supported by measurable changes

in the intestinal flora: the pathogens (E. coli and Clostridium) in the faeces were reduced, while the growth of the desirable lactobacilli was promoted (sampling on day 21). The trial design and results are shown in table 1. A closer look at the performance data shows a clear growth advantage in broilers supplemented with wood lignans com- pared to the positive control with Virginiamycin, especially from day 9 to day 22 (PC 660 grams body weight vs. NC + wood lignans 1003g body weight); afterwards the difference remained constant until the end of the fattening period on day 42.

The difference in development be- tween the exper- imental groups is clearly visible on day 19; left pho- to: positive con- trol with Virgin- iamycin; right photo: negative control with wood lignans.

Table 1 – Trial design, performance data and faecal bacterial counts.


Virginiamycin agromed ROI

Feed intake d 1-42, g End weight d 42, g FCR d 1-42 Carcass, % Breast, % Thigh, %

E. coli, log10 CFU/g

Clostridium, log10 CFU/g Lactobacillus, log10 CFU/g

negative control --- ---

4,348d 2,626c 1.71d 67.8d 31.7c 31.9

6.58a 8.57a 4.29c

a,b,c,d significant differences p < 0.005 A,B,C,D significant differences p < 0.01

▶ POULTRY WORLD | No. 3, 2021 39 PC

positive control

16.5 ppm ---

4,328c 2,627c 1.68c 68.6c 31.1d 31.9

5.21bc 7.74a 6.98b


400 ppm 4,511b 3,132a 1.46a 68.9b 33.5a 32.0


6.47bc 7.94a

16.5 ppm 400 ppm 4,621a 3,076b 1.52b 69.6a 32.5b 31.7

4.96bc 6.53c

7,31ab NC + wood lignans PC + wood lignans

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