Growing concern about antibiotic growth promoters in animal nutrition has created efforts to use different plant compounds as possible natural alternatives. Phytogenic feed additives (phytogenics) are an extremely heterogeneous group of feed additives originating from leaves, roots, tubers or fruits of herbs, spices or other plants. In human nutrition, their appetizing and digestion-promoting effects have long been recognized and aromatic plants are traditionally used in human and veterinarian medicine. Previously, phytogenics significantly improved performance in piglet production (Miller et al., 2003). However, there are usually large differences in efficacy regarding the mode of action as well as effects on microflora, digestibility, performance and immunity, between different phytogenic products that are available in the market. These differences are mainly due to a large variation in ingredient composition of these products, which is often poorly defined. Thus, the aim of this study was to evaluate the effect of a defined phytogenic feed additive (Biomin® P.E.P.) on reproductive performance of sows.


Feeding trial

A feeding trial was conducted under guidance of Universidad Mayor, Santiago, Chile using eighty cross-bred (PIC 337 x Camborough 22) sows in two dietary treatments. A gestation diet (Table 1) was fed restrictedly (3 kg/d) from day 15 to day 3 before farrowing. Subsequently, a lactation diet was offered ad libitum until weaning, as shown in Table 1 below.

The diets were either supplemented or not supplemented (Control) with a phytogenic feed additive (Biomin® P.E.P.), resulting in the following treatment groups with 40 sows per group:


Control group:  Basal diet without additives
Trial group:  Basal diet + phytogenics (2 kg/t)


Table 1. Experimental diets for gestating and lactating sows

Ingredients (%)	Gestation	Lactation
Corn	50	62
Full fat soybean meal	-	7
Soybean meal	16	11
Wheat by-products	30	10
Energy supplement	-	5
Amino acids, minerals, vitamins	4	5
Chemical composition
ME (kcal/kg)	2958	3020
Protein (%)	16.4	15.0
Lysine (%)	0.75	0.90
Fiber (%)	4.6	3.1
Calcium (%)	0.7	1.0
Available phosphorus (%)	0.44	0.45

Results and Discussion

The phytogenic formula used in the present study is based on a defined blend of essential oils and fructooligosaccharides (FOS). Specific essential oils have the potential to increase palatability of diets, thus stimulating voluntary feed consumption in pigs (Steiner, 2006a). Addition of phytogenics to the diets increased feed intake in the lactation period (7.070 vs. 7.238 kg for the control and trial group, respectively).

Moreover, according to Kroismayr (2007), specific essential oils exert a stabilizing effect on the gut microflora of pigs, thus increasing nutrient uptake and reducing the production of toxic metabolites in the hindgut. In a study with piglets, supplementation of control diets with Biomin® P.E.P. reduced the levels of biogenic amines and ammonia, as well as the contents of volatile fatty acids, in the caecum and colon. Additionally, the size of Peyer’s Patches was smaller in pigs fed phytogenics, indicating less digestive stress.

It is generally accepted that a higher feed intake in lactation together with improved digestion results in an increased supply of nutrients and energy for the piglets in the milk. As illustrated in Figure 1, inclusion of phytogenics in diets of sows positively affected piglet performance as well. Compared to the control group, phytogenics improved growth performance of piglets, resulting in higher weaning weights by 6%. Table 2 summarizes some of the performance parameters as influenced by supplementation of the diets with phytogenics.


Figure 1. Effect of phytogenics on weaning weight and daily weight gain of piglets

Table 2. Effect of phytogenics on sow performance

	Control	+ Phytogenics
Piglets born alive per litter	11.7	11.7
Body weight of piglets at birth (kg)	1.27	1.33
Litter weight at birth (kg)	14.93	15.52
Piglets weaned per litter	10.5	10.7
Litter weight at weaning (kg)	61.83	65.81

The results obtained in the present study are in general agreement with previous trials conducted in France (Steiner, 2006b) and the North America (Miller et al., 2003).


Economical analysis

Profitability of piglet production largely depends on feed intake of sows as well as on the resulting performance of the litter. Although the overall feed costs (including cost of the additive) were higher by 16% in the trial group, the improvement in performance in this group generated additional earnings, which finally resulted in an additional annual profit amounting to 21 USD per sow. It is noteworthy that this calculation only takes into account the benefits over feed costs and does not consider shorter average wean-to-first-service interval or reduced incidence of health problems. These factors are considered to further contribute to profitability in piglet production.


Conclusion

As shown in the present study with sows, well-selected phytogenic compounds represent a Natural Growth Promoter in piglet production. Supplementation of sow diets increases body piglet weaning weights and improves profitability in sow production operations.


Acknowledgement

The authors would like to thank Dr. Esteban Gigoux (swine consultant, Chile) for supervising the trial, and Cristian Dasso and Alexi Videla (Centrovet, Santiago, Chile) for support of this study. References are available from the author upon request.


Authors: Maurice RACOUSIER¹, Tobias STEINER^2
1 Universidad Mayor, Santiago, Chile
² BIOMIN GmbH, Herzogenburg, Austria