The influence of some herbs substituting for antibiotic growth promoter on the results of broiler chickens rearing

¹Ryszard K. Pisarski, ¹Mirosław Zięba, ²Krzysztof Szkucik

^1- Institute of Animal Nutrition, ^2- Department of Food Hygiene of Animal Origin

Agricultural University, 20-950 Lublin, Akademicka 13 St.

The search for alternatives to antibiotic growth promoters (AGP) turned the attention to herbs, owing to their beneficial characteristics recognized for centuries. Apart from different composition and activity of herbs they are believed to improve metabolism rate and animal welfare which predestines them to substitute for AGP in comound feds. The aim of presented study was to search for the effect of some common herbs on the productive results of broiler chickens rearing.

Material and methods

The experiment was carried out with 210 ROSS broilers reared in cages under regular environmental conditions. One-day-old chicks were randomly allocated into one control (C) and six experimental groups (1- 6), 3 replications each. The compound feed for control birds contained AGP (Flavomycin ) and 2% of dried neutral green forage, whereas experimental feeds contained 2% of dried herbs, as follows: 1-hop cone (Humulus lupulus L.), 2- lime tree (Tilia cordata L.), 3-lemon balm (Melissa officinalis L.), 4-pansy (Viola tricolor L.), 5-peppermint (Mentha piperita L.) and 6-nettle (Urtica dioica L.). Broilers were fed ad libitum and they were reared till 42 days of age.

On the last day of experiment 8 chickens from every group (4 ♂ and 4 ♀) of average body weight were selected, slaughtered and dissected. The effect of herbs was expressed on the basis of final body weight, feed conversion, dressing percentage and the share of muscles and abdominal fat in chilled carcass. The data underwent two-way analysis of variance by ANOVA.

Results

The analysed results are given in a table below. With respect to body weight it should be emphasised that it was rather low due to the very warm weather during the last several days of rearing.

Table 1. The effect of herbs fed to broiler chickens instead of AGP

Characteristic	Group
	C- AGP	1- hop cone	2- lime tree	3-lemon balm	4- pansy	5- pep-permint	6- nettle
Body weight (g)	1560^AB	1194^C	1414^Bb	1585^ABa	1642^A	1608^ABa	1638^A
Feed convers.(kg kg^–1)	1.92^A	2.21^B	2.01^AC	2.07^C	2.04^AC	2.10^BC	1.90^A
Dressing percentage	71.2^a	71.0^a	73.1^b	73.1^b	73.0^b	72.7^b	73.2^b
Share of muscles (%)	34.9^a	36.0^a	35.8^a	38.1^b	37.1^ab	35.2^a	39.7^b
Share of abdom. fat(%)	1.9^ae	2.4^b	1.8^ad	2.1^ab	1.5^cd	1.6^cde	1.4^c

A, B ... means with different superscripts in rows differ significantly at p ≥ 0.01

a,b … means with different superscripts in rows differ significantly at p ≥ 0.05

It reveals that not every herb used instead of AGP is effective enough. Broilers given hop cone gained significantly lower body weight than the control ones and the other experimental chickens. Pretty similar reaction was observed with respect to feed conversion. On the other hand, the best results were obtained in the broiler chickens given the feed fortified with nettle substituted for flavomycin.

Conclusion

Supplementing broiler feeds with 2% of dried lime tree, lemon balm, pansy, peppermint and/or nettle does not decrease examined productive characteristics, compared to AGP.