The abundance of unique herbs in our country provides for the opportunity to manufacture feed additives, applicable in livestock breeding, which can successfully substitute for the already banned antibiotics, used for many years as growth stimulants.

The aim of this research is to determine the effect on productivity of pigs, when supplemented with the biologically active herbal feed additive VemoHerb BP to compound feed.

The series VemoHerb is a feed additives produced by “Vemo 99” Ltd., Sofia, Bulgaria and is a mixture of biologically active natural compounds.

The product contains saponins, sterols, flavonoids, tannins, polyphenols and others and has been tested in a series of experiments in starter and grower pigs. The trials with pigs have been conducted in the Experimental site of the Institute of Stock-Breeding Sciences, Konstinbrod, Bulgaria.

Results and Discussion

The trial is held in a pig farm and it involved 153 male and female castrated pigs of two-line hybrid Landrace x Large White in weight period of 6 to 20 kg included immediately after weaning the animals.

The first is control group and the animals received compound feed with added antibiotic. For the second group feed formula is enriched with a test product VemoHerb BP and a third group is with an acidifier. The obtained results are shown in the following table:

Groups Parameters	Control + antibiotic	Control + VemoHerb BP	Control + acidifier
Total number of pigs	51 (3x17)	51 (3x17)	51 (3x17)
Period, days	68	68	68
Body weight, kg - at the beginning - at the end	6.58 19.97	6.10 22.0	6.02 20.59
Growth, g/day - % compared to Control	197±70.6c* 100.0	234±68.4c 118.8	214±62.9 108.6
Feed intake: - Intake/day/g - for 1 kg gain, kg - % compared to Control	570±10.3cd 2.895±1.35ab 100.0	585±34.0ce 2.503±0.98a 86.4	542±37.9de 2.528±1.0b 87.3

*The value marks of the same letters are significant at: a, b – P < 0.05; c – P < 0.01; d, e - P < 0.001

The amount of the feed per day of one pig in groups is 570 g, 585 g and 542 g. Pigs in the second group accepted three percent more feed than the control animals, while in the group receiving acidifier, the assumed feed is fairly lower. The addition of VemoHerb BP has a positive effect of the growth of pigs. The average daily gain for animals from the second group is 234 g or with 18.8 % higher compared with the control animals – 197 g. In pigs from the third group that have received the acidifier is also achieved better growth by 8.6% compared to the control animals -214 g, although the difference is not statistically proven.

The average daily gain in groups that have received VemoHerb and acidifier is with 8.5% higher in the group with addition of VemoHerb BP compared to the group with the acidifier.

Analogical results are observed in feed intake. The best conversion of the feed is reached in the second group – 2.5 kg, followed by a third group - 2,53 kg compared with control animals - 2,9 kg. The mortality rate in pigs in the control group and the group with the addition of acidifiers was practically the same, while in the group with addition of VemoHerb it was four points lower.

The next trial is held with 24 male castrated and female grower pigs from, ,,Dunabe byala” breed divided into four groups. The aim of this research is to determine the effect from the addition of VemoHerb compared to the recommended dosage of 150 g/t feed. The obtained results are presented in the following table:

 

Groups Parameters	Control without VemoHerb	ІІ group with VemoHerb 75 g/t feed	ІІI group with VemoHerb 150 g/t feed	ІV group with VemoHerb 225 g/t feed
Total number of pigs	6	6	6	6
Trial period, days	42	42	42	42
Body weight, kg - at the beginning - at the end	31.16±1.03 56.78±2.65	29.92±1.34 56.62±1.20	30.67±1.22 59.83±1.31	28.18±1.54 57.470±1.78
Growth, g/day - % compared to Control	610±0.04ab 100.0	636±0.02cd 104.03	694±0.02 ac 113.7	697±0,02bd 114.2
Feed intake: - Intake/day/kg - % compared to Control - for 1 kg gain, kg - % compared to Control	1.98±0.06abc 100 3.248±0.18 100	2.095±0.02a 2105.7 3.296±0.18abc 101.4	2.125±0.01c 107.3 3.061±0.08a 94.2	2.109±0.01b 106.5 3.024±0.07b 93.1

*The value marks of the same letters are significant at: a, b, c, d – P < 0.05.

The experimental data shows that for the period from 42 days, the pigs have better intensity in growth, the average daily gain is from 610 g to 696 g/day. Compared with control animals, in pigs of II, III and IV groups with increasing the dose with addition of VemoHerb increases the yield, respectively, with 4%, 13.7% and 14.2% compared with the control group.

At a lower by 50% participation rate of the test product compared with the recommended optimal dose of 150 g / t, growth in pigs reduces round by 9%. Compared with pigs from the control group, the animals from the third and fourth group have the same intensity in growth and FCR, which shows that the increase of the dosage of VemoHerb does not lead to a significant increase in growth in pigs. Therefore, the recommended dosage of 150 g / t feed is optimal.