Effects of Herbiotic FS supplementation on growth performance, nutrient digestibility, blood profiles, and faecal scores in weanling pigs

ABSTRACT This study was conducted to investigate the effects of Herbiotic FS supplementation on growth performance, nutrient digestibility, blood characteristics, and faecal scores in weanling pigs. A total of 150 weanling pigs [(Landrace×Yorkshire)×Duroc] with an average initial body weight of 8.02 ± 0.92 kg were randomly assigned to 5 dietary treatments (5 replicate pens per treatment with 6 pigs per pen). The dietary treatments were as follows: (1) negative control: basal diet, (2) positive control: basal diet + 150 mg/kg apramycin, (3) Herbiotic1: basal diet + 250 mg/kg Herbiotic FS, (4) Herbiotic2 (basal diet + 500 mg/kg Herbiotic FS), and (5) Herbiotic3: (basal diet + 250 mg/kg Herbiotic FS + 75 mg/kg apramycin). During days 1–7, pigs fed positive control, Herbiotic2 and Herbiotic3 diets had improved average daily gain and gain:feed ratio compared with those fed negative control or Herbiotic1 diets (P < 0.05). On day 21, pigs fed positive control and Herbiotic3 diets had increased nitrogen digestibility compared with those fed negative control or Herbiotic1 diets (P < 0.05). In conclusion, Herbiotic FS supplementation decreased the pathogenic count in the gut owing to its antimicrobial activity and this in turn caused the nutrients more available to the animal contributing to the growth.


Introduction
During the last decades, phytogenic feed additives have been wildly used as an alternative to antibiotics because of their plant-derived property and growth-promoting effects (Hong et al. 2004;Wang et al. 2007;Wang et al. 2008;Windisch et al. 2008;Jang et al. 2010;Ao et al. 2011). Valchev et al. (2009) demonstrated that herbal extracts (150 mg/kg) in pig diet could increase growth performance, feed efficiency, and immune-related blood characteristics. It is suggested that the beneficial effects of herbs or herbal extracts may arise from increased feed intake and secretion of digestive enzymes, immune stimulation, anti-bacterial, anti-viral, and antioxidant properties (Wenk 2003;Kim et al. 2010). Krotkiewski and Janiak (2008) and Yang et al. (2009) also demonstrated a synergistic interaction between the components of herbal mixture in vivo and in vitro.
Herbiotic FS is a mixture of thyme, buckwheat, turmeric, black pepper, and ginger, and is developed for a better and safer alternative to antibiotics and chemical growth promoters. It has lower minimum inhibitory concentration as compared to zinc bacitracin and other synthetic antibiotics and has better growth-promoting effects (Dinodiya et al. 2015). Herbiotic FS augmented the population of beneficial microbiotia in the gut through its prebiotic oligosaccharides, prevented the irritation of the intestine and increased the number and height of the intestinal villi in broilers (Dinodiya 2012). However, the information about Herbiotic FS supplementation in weanling pigs is still scarce. This study was conducted to investigate the effects of Herbiotic FS supplementation on growth performance, nutrient digestibility, blood characteristics, and diarrhoea score in weanling pigs.

Materials and methods
The experiment was conducted at the Experimental Unit of the Dankook University (Cheonan, Republic of Korea). The protocol for the current experiment was approved by the Animal Care and Use Committee of Dankook University.

Sampling and measurements
Individual body weight and feed consumption on a pen basis were measured at the beginning, day 7, 21, and 42 of the experimental period to calculate the average daily gain (ADG), average daily feed intake (ADFI), and gain:feed ratio (G:F). To determine the apparent total tract digestibility (ATTD) of dry matter (DM), nitrogen (N), and gross energy (GE), pigs were offered experimental diets supplemented with chromic oxide as an indigestible marker at the level of 0.2% from days 3 to 7, 17 to 21, and 38 to 42. On day 7, 21, and 42, faecal samples were collected from at least three pigs per pen by rectal massage. After collection, all feed and faecal samples were stored immediately at −20°C until analysis. Faecal samples were oven-dried at 70°C for 72 h, after which feed and faecal samples were finely ground to pass through a 1-mm screen. The DM and N in feed and faecal samples were determined according to the methods established by the AOAC (2000). GE was determined by measuring the heat of combustion in the samples, using a bomb calorimeter (Parr 6100; Parr instrument Co., Moline, IL). Chromium levels were determined via UV absorption spectrophotometry (UV-1201, Shimadzu Corp., Kyoto, Japan) using the methods described by Williams et al. (1962). The ATTD was then calculated using the following formula: ATTD (%) = {1-[(Nf × Cd)/(Nd × Cf)]} × 100, where Nf = nutrient concentration in faeces (% DM), Nd = nutrient concentration in diet (% DM), Cd = chromium concentration in diet (% DM), and Cf = chromium concentration in faeces (% DM).
On day 7, 21, and 42, two pigs (1 gilt and 1 barrow) were selected at random from each pen and blood samples were collected via jugular venipuncture into both a nonheparinized and a K 3 EDTA vacuum tube (Becton Dickinson Vacutainer Systems, Franklin Lakes, NJ) to enable evaluation of the serum and whole blood, respectively. The white blood cell (WBC), red blood cell (RBC) and lymphocyte counts were analysed using an automatic blood analyser (ADVIA 120, Bayer, USA). The serum samples were then centrifuged (2000 × g) for 30 minutes at 4°C, after which the immunoglobulin G (IgG) was determined using a nephelometer analyser (Behring, Marburgh, Germany).
Subjective diarrhoea score was recorded daily from days 1 to 7 by the same person and was based on the following: 1 = wellformed faeces, 2 = sloppy faeces, and 3 = diarrhoea. Score was recorded on a pen basis following observations of individual pig and signs of stool consistency in the pen. The score is reported as average daily diarrhoea of individual pig score.

Statistical analysis
In this experiment, all data were analysed using a randomized complete block design following general linear model procedures of SAS (1996), with each pen being used as the experimental unit. Differences between treatments were detected by Tukey's multiple range test. The data were expressed as means and pooled standard error of the mean. Significance was defined as P < 0.05.

Growth performance
During phase 1, pigs fed PC, H2 and H3 diets had improved (P < 0.05) ADG and G:F compared with those fed NC and H1 diets, but ADFI was not affected (P > 0.10) by treatments (Table 2). During phase 2, ADFI in pigs fed PC and H3 was increased (P < 0.05) when compared with that of pigs fed NC diet, whereas ADG and G:F were unaffected (P > 0.10). During phase 3, pigs fed PC and H3 diets showed higher (P < 0.05) ADG than that of pigs fed NC diet, but ADFI and G:F were not affected (P > 0.10). Overall, pigs fed PC, H2, and H3 diets had improved (P < 0.05) ADG when compared with those fed NC diet, although ADFI and G:F were not affected (P > 0.10).

Nutrient digestibility
Pigs fed PC and H3 diets had increased (P < 0.05) ATTD of N compared with those fed NC and H1 diets (Table 3) at day 21. However, other determined ATTD were not affected by dietary treatments (P > 0.10).

Blood profiles
On day 7, RBC concentration in PC, H2 and H3 treatments was higher (P < 0.05) than that in NC treatment (Table 4). Pigs fed H1, H2, and H3 diets had increased (P < 0.05) lymphocyte (day 42) and IgG (day 21) concentrations compared with those fed NC and PC diets. No other effects were observed among treatments (P > 0.10).

Diarrhoea score
No significant difference (P > 0.10) was observed on diarrhoea score among dietary treatments during the experiment (Table 5).

Discussion
In the present study, the pigs fed PC, H2 and H3 diets had greater ADG (during phase 1 and overall period) and G:F (during phase 1) compared with those fed NC and H1 diets. During phase 2, ADFI showed an increase when pigs fed PC or H3 diets compared with those fed NC diet. Additionally, during phase 3, pigs fed PC or H3 diets exhibited higher ADG than those offered NC diet. The effects of Herbiotic FS treatment on growth performance were more evident during first week after weaning, indicated as improved G:F in phase 1 when 500 mg/kg Herbiotic FS or a combination of 250 mg/kg Herbiotic FS and 75 mg/kg apramycin were included in diets, whereas G:F was not affected in other determined phases. In agreement with our results, Huang et al. (2012) reported that medicinal herb supplementation (Panax ginseng, Dioscoreaceae batatas, Atractylodes macrocephala, Glycyrrhiza uralensis, Ziziphus jujuba, and Platycodon grandiflorum) improved ADG and decreased feed:gain during the first 2 weeks after weanling. Czech et al. (2009) suggested that herbal extracts (garlic, liquorice roots and tiller, thyme herb, and caraway fruits) stimulated growth performance in pigs. Kwon et al. (2005) reported that with increasing (0, 500, 1000, and 1500 mg/kg) the level of dietary herbal mixtures (Artemisia, Acanthopanax and garlic mixtures), linear increases on ADG and G:F and a decrease on ADFI were observed in weanling pigs during days 0-20. Yuan et al. (2006) also observed that dietary supplementation of a polysaccharide isolated from Astragalus membranaceus improved ADG and tended to increase ADFI in weanling pigs, but feed conversion ratio was not affected. Wenk (2003) indicated that supplementation with herb additives could improve the flavour and palatability of feed and influence the eating pattern, secretion of digestive enzymes, and feed intake. A wide range of spices, herbs, and extracts exert beneficial effect in the digestive tract by increasing the activity of digestive enzymes at the gastric mucosa and feed intake (Srinivasan et al. 2004). Frankic et al. (2009) noted that improved growth performance, when inclusion of herbs and spices in diets, could be contributed to the desired organoleptic qualities of the diets and stimulate the appetite of animals. Meanwhile, herbs could reduce the subclinical or clinical infections due to their antimicrobial activity, and subsequently benefits pig's health (Huang et al. 2012). The treatments with 150 mg/kg Means in the same row with different superscripts differ (P < 0.05). Means in the same row with different superscripts differ (P < .05).
apramycin or a combination of 250 mg/kg Herbiotic FS and 75 mg/kg apramycin increased the ATTD of N, whereas no effects on ATTD of DM and GE were observed with any of the dietary treatments. Herbs may increase activity of digestive enzymes of gastric mucosa and balance the intestinal microbiota, thereby improving nutrient digestibility (Jamroz et al. 2003;Huang et al. 2012). The increased ATTD of N may help to, at least partially, explain the improved growth performance. The gastrointestinal tract is the largest immunological competent organ in the body, and studies have indicated that the maturation of gastrointestinal tract and the development of the immune system depend on the composition of the indigenous microbiota (Insoft et al. 1996;de Vrese and Marteau 2007). Inclusion of herbs or herbal extracts could influence the gut intestinal microorganisms, which are necessary for the development of the gut immune system (Si et al. 2006). Several studies suggested that, administration of herbs could increase blood circulation, metabolic process, and the immune system of animals (Chakravarty and Yasmin 2005;Trevisi et al. 2007). In the present study, pigs fed with Herbiotic FS diets showed increased RBC (day 7), IgG (day 21), and lymphocyte (day 42) concentrations compared to pigs fed with NC and PC diets, suggesting that Herbiotic FS had beneficial effects on immune function. Herbs may stimulate immune function in livestock by influencing the growth of pathogenic microorganism in gastrointestinal ecosystems (Wenk 2003;Ali et al. 2008;Windisch et al. 2008). The improved immunity function may consequently contribute to the improved growth performance.
Post-weaning diarrhoea is one of the serious problems faced in swine production, especially within the first week after weaning. Herbs may reduce diarrhoea occurrence via improving intestinal microbial balance. Huang et al. (2012) reported that inclusion of medical herbs reduced diarrhoea score during the first 10 days of the experiment period. However, in the present study, diarrhoea score was not affected by dietary treatments. Similarly, Zhang et al. (2012) demonstrated that phytoncide supplementation (flavonoid, phenolic compounds, alkaloid, tannin, terpene, and saponin) had no effect on diarrhoea score. The lack of effect on diarrhoea score in the present can be explained by the generally good health status of the pigs and good hygienic conditions of the research facilities.
In conclusion, Herbiotic FS supplementation decreased the pathogenic count in the gut owing to its antimicrobial activity and this in turn causes the nutrients more available to the animal contributing to the growth.