Effects of phytogenic substances on growth performance , digestibility of nutrients , faecal noxious gas content , blood and milk characteristics and reproduction in sows and litter performance

Forty sows (Landrace×Yorkshire), with an average body weight (BW) of 184.5 kg and average parity of 2.65, were used to determine the effects of a phytogenic feed additive (PFA) on growth performance, digestibility of nutrients, faecal NH3-N gas content, blood and milk characteristics and litter performance. Dietary treatments included: 1. control (CON) and 2. PFA (basal diet + 0.04% phytogenic feed additive). Digestibility of dry matter (DM) was increased signifi cantly (P<0.05) in PFA treatment. Faecal ammonia nitrogen (NH3-N) measured at the end of experiment was reduced (P<0.05), however no signifi cant effect (P>0.05) was observed on the digestibility of protein in PFA. On day 1 of lactation, albumin and lymphocyte were decreased (P<0.05) whereas WBC was increased signifi cantly (P<0.05) when sows were fed the PFA diet. IgG content in milk was increased by PFA at farrowing and after farrowing 12 h (P<0.01; P<0.05). Similarly, IgA content in milk was increased by PFA after farrowing 12 h (P<0.01). Protein and solid concentration in colostrum were signifi cant lower (P<0.01; P<0.05) in PFA treatment than CON treatment after farrowing 12 h. In conclusion, feeding 0.04% of PFA from day 107 of gestation to day 21 of lactation improved DM digestibility, RBC and WBC concentration, and lactose, IgG and IgA production in colostrums and decreased faecal NH3-N concentration.


INTRODUCTION
The use of antibiotics as growth promoters in animal feeds is facing reduced social acceptance due to the appearance of residues and resistant strains of bacteria (Gustafson and Bowen, 1997).The use of antibiotics has been prohibited in the European Union since January 2006 (Regulation 1831/2003/EC).Natural, safe and inexpensive feed additives that do not endanger the environment with residues in wastes should be developed.It is noteworthy that there is a revival of phytogenic feed additives in the world, as a successful alternative to the prophylactic use of antibiotics against pig dysentery (Bilkei, 1995).Phytogenic feed additive (PFA) infl uenced positively daily feed intake, daily weight gain, and feed utilization in growing pigs and improved growth performance in pigs (Gunter and Bossow, 1998;Baumann et al., 2003).
Our study was concerned on one of PFA products named Fresta F Conc ® (Delacon Co., Ltd, Steyregg, Austria).The product is made of essential oils, fl avonoids, pungent substances, and mucliages.Major components consist of up to 40% of the essential oil.Essential oils are aromatic oily liquids obtained from plant material (fl owers, buds, seeds, leaves, twigs, bark, herbs, woods, fruits, and roots).Most of essential oils are classifi ed as Generally Recognized as Safe (GRAS), and have been approved for food and beverage consumption by the United States Food and Drug Administration.
The objective of the current experiment was to determine whether additional PFA during late-gestation (day 107) and lactation would affect sow and litter.The hypothesis was that the antibacterial, appetite enhancing ability of PFA would increase sow's performance, improve sow's immunity, decrease excretion of nutrients, ameliorate milk characteristics and have effect on reproduction parameters.

Experimental design and measurements
The experimental protocol was approved by the Animal Care and Use Committee of Dankook University.A total of forty (Landrace×Yorkshire) sows, with an average body weight of 184.5 kg (from 150.7 to 220.5 kg) and average parity 2.65 (from 1 to 4), were used for this experiment in each treatment of twenty sows.Experimental treatments were as follows: 1. control (CON), basal diet), and 2. PFA (basal diet + 0.04% phytogenic feed additive).Phytogenic feed additive was replaced with maize in the diets.Experimental diets were fed from day 107 of gestation to day 21 of lactation except at the day of parturition.On day 107 of ge-station, sows were placed in an environmentally regulated farrowing facility until weaning (day 21).Temperature was maintained at a maximum of 20°C.Sows were housed in farrowing crates (2.1 × 0.6 m) with an area (2.1 × 0.6 m) on either side of the crate for the piglets.Before farrowing, rubber mats were put down as surface for piglets to lie on.Heat lamp was suspended above each rubber mat to keep the temperature for newborn piglets constant at 35°C.
Sows were fed 2 kg of experimental diets (%: total lysine 0.9, Ca 0.8 and P 0.7; Table 1) with or without 0.04% of added PFA to allow for adaptation to the diets before parturition.On the day of parturition, the sows were not offered feed.From day 1 of lactation, sows were allowed ad libitum access to feed and water, and feed intake was recorded weekly and average daily feed intake (ADFI) was calculated.
Backfat thickness was measured at last rib (65 mm from the center line of the back) using real-time ultrasound (Piglog105, version 3.1, Denmark).Values from the two measurements were averaged to obtain a single backfat measurement.Backfat thickness was measured on day 0 and 21 after farrowing.During experimental period, individual numbers of piglets alive and death per litter were recorded.Individual pig weight was recorded at birth and weaning to determine weight gain.After weaning, sows were transferred to pens adjacent to mature boars and were directly exposed to boars twice a day for oestrus detection.
During the lactation, chromium oxide (0.20%) was used as an indigestible marker to calculate digestibility coeffi cients.At the end of lactation period, faecal samples were taken from each sow to determine the digestibility of DM and nitrogen.All the faecal samples, as well as feed samples were stored in refrigerator until analysis.Before chemical analysis, faecal samples were thawed and dried at 70°C for 72 h and subsequently ground to pass through a 1-mm screen.All the feed and faecal samples were analysed for DM and N according to AOAC (1995), while chromium was determined by UV absorption spectrophotometry (Shimadzu, IJV-1201, Japan) according to Fenton and Fenton (1979).Nitrogen was measured using a Kjeltec 2300 Analyzer (Foss Tecator AB, Hoeganaes, Sweden).Faecal NH 3 -N concentration was determined according to the method of Chaney and Marbach (1962).
Within 6 h after farrowing, ten sows were randomly chosen from each treatment and blood samples were collected from cervical vein into both K 3 EDTA vacuum tubes and clot activator vacuum tubes (Becton Dickinson Vacutainer Systems, Franklin Lakes, NJ, USA) immediately and stored in refrigerator at -4°C.The same sows were bled again on day 1 and day 21 of lactation.The blood cell counts (WBC, RBC and lymphocyte) were analysed by the automatic blood analyser (ADVIA 120, Bayer, NY).Samples for serum analysis were centrifuged at 3.000 g for 15 min and serum was separated.Total protein, albumin and IgG concentrations in serum were determined by the automatic biochemistry analyser (HITACHI 747, Japan).
Furthermore, approximately 30 to 40 ml of colostrum was collected from functional glands of these sows within 12 h from termination of farrowing.On day 1 and 21 of lactation, 30 to 40 ml of mature milk was collected.The colostrum and milk samples obtained were analysed for concentrations of fat, protein, lactose, solids, IgG and and IgA.Milk fat, protein, lactose and solids were analysed by a commercial laboratory using a Milkoscan System 4000 (Foss North America, Eden Prairie, MN; AOAC, 1990).The concentrations of immunoglobulins (IgG, IgA) were determined by radial immunodiffusion (Mancini et al., 1965).

Statistical analysis
In this experiment, sow was considered the experimental unit.Data were analysed using the GLM procedure of SAS (1996).Farrowing group was used as a block.The analysis of sow backfat thickness and change during lactation used fat depth at farrowing as covariates.Piglet birth weight was used as covariates for weaning weights during lactation.Lactation length was used as a covariate for number of pigs weaned, survivability, sows and piglets weaning weights, sows ADFI, and return of oestrus and backfat thickness depth change.Variability of all the data was expressed as standard error (SE) and a probability level of P<0.05 was considered as statistically signifi cant.

Growth performance of sows and piglets.
There was no signifi cant difference in ADFI between dietary treatments (Table 2).Neither backfat loss nor return of Digestibility and faecal NH 3 -N content.During the experimental period, digestibility of DM was increased (P<0.05) by dietary supplementation with 0.04% PFA (Table 4).There was no signifi cant difference in digestibility of nitrogen between the treatments.Table 5 shows the effect PFA on faecal NH 3 -N concentration in sows.On day 1, 2 and 4, no statistical differences (P>0.05) were found in NH 3 -N concentration between treatments.On day 7, NH 3 -N concentration in sows fed PFA diet was lower than sows fed CON diet (P<0.05).Blood characteristics.No signifi cant differences were observed for total protein, albumin, IgG, RBC, WBC, lymphocyte concentrations at farrowing (P>0.05;Table 6).On day 1 of lactation, albumin and lymphocyte contents were decreased (P<0.05),whereas WBC content was increased when sows were fed the diet with 0.04% PFA.On day 21 of lactation, RBC and WBC were increased signifi cantly (P<0.05) in PFA treatment compared with CON treatment.

Milk characteristics.
Immunoglobulin G concentration was increased in PFA treatment at farrowing (P<0.05;Table 7).When sows were fed PFA diet, milk protein and solid concentration were signifi cantly lower in colostrum (12 h) than basal diet (P<0.05),however no differences were observed in milk (day 21) between treatments (P>0.05).Obtained data show an increase (P<0.05) in lactose, IgG and IgA in colostrum in PFA treatments.  1 2 pooled standard error 3 NS -not signifi cant, * P<0.05 DISCUSSION Phytogenic feed additives as growth promoters are controversially discussed in the literature (Sivropoulou et al., 1996;Tsinas et al., 1998;Khajarern and Khajarern, 2002).The positive effect of dietary essential oils on sow health and production may be because of the effects of antioxidant (Aeschbach et al., 1994), antibacterial (Didry et al., 1994), antiphlogistic (Azuma et al., 1986), and antiinfl ammatory (Azuma et al., 1986) effects.Khajarern and Khajarern (2002) stated that carvacrol and thymol affected the mucosal membrane in the intestines and accelerated the renewal rate of enterocytes on the surface intestinal villi; this would reduce pathogen attachment to enterocytes and improve nutrient absorption capacity.Furthermore, these authors stated that origanum essential oils act not only as alternative antibacterial performance promoters, digestion aids, and appetite enhancers in sows, but also as natural feed additives to enhance growth and reproductive performance in sows (Khajarern and Khajarern, 2002).In one study, feed supplementation with 1000 ppm oregano during the prefarrowing and lactation period signifi cantly improved weight gain of pigs (Amrik and Bilkei, 2004).When benefi cial responses in litter performance from essential oils were observed, sows were fed essential oils for at least 10 d, and usually 14 d, prior to farrowing (Amrik and Bilkei, 2004;Mauch and Bilkei, 2004).We began feeding our experimental diets no more than 7 d prior to farrowing.Inconsistent results might be due to this reason.
Obtained data suggested that digestibility of DM was increased by the supplementation of PFA.Wang et al. (1999) observed that essential oils stimulated both organic matter and microbiotical digestion.Previous research (Didry et al., 1994;Tsinas et al., 1998) found that essential oils enhanced the regulation of gastrointestinal metabolism and exerted antibacterial properties in the digestive tract of pigs.Cho et al. (2006) demonstrated that NH 3 concentration in faeces was signifi cantly reduced by addition of essential oils by improving N digestibility.However, in our study, no improvements in N digestibility were noted when sows were fed on diets supplemented with PFA.Therefore, the reduction of NH 3 -N concentration in faeces may not be the result of increased nutrient digestibility, but rather of the alteration of intestinal microfl ora.In fact, Mcintosh et al. (2003) observed that a blend of essential oil compounds inhibited the growth of Clostridium sticklandii and Peptostreptococcus anaerobius which are hyperproducing ammonia species.
Pungent substances (i.e.garlic, black pepper and chilli), the active components of PFA, have activation of blood circulation and metabolic processes (Rodas, 2006).Iranloye (2002) had shown that daily feeding of rats with 200 mg/kg garlic juice increased the RBC and WBC.It is also possible that the end product of pungent substances metabolism in the body stimulates the kidney directly to cause formation and secretion of erythropoietin.The immunomodulatory effects of naturally occurring sulphur compounds in pungent substances include WBC, RBC being enhanced signifi cantly in animals (Kuttan, 2000).The present results confi rmed their fi ndings.Albumin and lymphocyte concentrations were decreased (P<0.05).The exact mechanisms of this additive can not be explained clearly by current study.In the future more studies should be conducted.
Our result was in agreement with previous study by Xie et al. (1999) who found that when essential oils (leleshwa oil) were given to sows during the last week of gestation and throughout lactation, milk protein in colostrum decreased signifi cantly compared with control treatment.The mechanisms by which the essential oils may be affecting milk protein are unknown.In the 6th week prior to parturition, colostrogenesis has begun.Antibodies found in the initial lacteal secretions partly (IgA) or solely (IgG) originate from the sows circulation (Watson, 1980) and a boost to serum antibodies during this period would therefore be thought to lead to an improvement in colostrum levels.Also, Mauch and Bilkei (2004) reported that essential oils (oregano) decreased populations of undesirable microorganisms and stimulated the secretion of antibodies maybe positively infl uenced IgG and IgA level in colostrum.

CONCLUSIONS
The results presented in this article should encourage the scientifi c community to continue investigations of phytogenic feed additives as alternatives to antibiotics.This production is effective in improving WBC, RBC and colostrum characteristics and reducing NH 3 -N.In contrast, 0.04% phytogenic feed additives (PFA) has no apparent effect on sows or piglets growth performance.Further research is needed to determine the optimum level of PFA needed in gestation and lactation diets.

Table 2 .
Effect of phytogenic feed additive on growth performance in sows

Table 3 .
Effect of phytogenic feed additive on growth performance in litters P>0.05).No differences (P>0.05) were observed on average piglet weight at weaning.Number of pigs per litter and pig survival were not affected by dietary treatment (P>0.05).

Table 4 .
Effect of phytogenic feed additive on digestibility of nutrients in sows

Table 6 .
Effect of phytogenic feed additive on blood characteristics in sows

Table 7 .
Effect of phytogenic feed additive on milk characteristics in sows