Use of lemon grass oil as feed additive in weanling pigs diets

Deutscher Tropentag 2002
Witzenhausen, October 9-11, 2002
Conference on International Agricultural Research for Development
Use of Lemon Grass Oil as Feed Additive in Weanling Pig Diets
Wandee Tartrakoona, Kattika Wuthijareea, Therdchai Vearasilpa, Udo ter Meulenb
a Department of Animal Science, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200,
Thailand. E-mail: agitvrsl@chiangmai.ac.th b Institute for Animal Physiology and Animal Nutrition, Georg-August-University, Kellnerweg 6, 37077 Göttingen, Germany. E-mail: umeulen@uni-goettingen.de
Abstract

An experiment was conducted at Chiang Mai University to determine the use of lemon
grass oil as additive in weanling pigs. 28 days old weaned piglets were randomly
distributed into 5 groups of 6, 4, 5, 4 and 4 animals each in a completely randomised
design (CRD). The piglets were housed in individual cages. Diet 1 (control diet) was a
basal diet containing corn-soybean meal. Diet 2 was a basal diet supplemented with
0.75 g tetracycline /kg basal diet. diet 3, 4 and 5 were basal diets supplemented with
lemon grass oil at 1, 2.5 and 5 ml/kg diet respectively. Diets were formulated according
to NRC (1998) requirements. The productive performance and faecal characteristics of
the pigs were determined beginning at 7 ± 0.8 kg BW until 20 ± 0.8 kg BW. Average
daily gain (ADG) and feed conversion ratio (FCR) of pigs fed diet 1 to 5 were 420, 390,
330, 320 and 380 g/d and 1.89, 1.88, 1.81, 1.87 and 1.73, respectively. There was no
significant difference of ADG among treatments. The inclusion of lemon grass oil 5
ml/kg diet tended to improve FCR of piglets. The pigs fed control diet had higher
average daily feed intake (ADFI) (p<0.05) than pigs fed diets containing 1 and 2.5 ml
lemon grass oil /kg diet (diet 3 and 4). There were no differences (p>0.05) in ADFI of
pigs fed diet containing lemon grass oils (diet 3, 4 and 5). The faecal score (shape and
colour) of the pigs fed diet 4 and 5 was better than in pigs fed other diets (p<0.05). The
results suggest that lemon grass oil can substitute tetracycline as feed additive.
Keywords: Lemon grass oil, pig production, feed additive
Introduction
Sub-therapeutic levels of antibiotics are used in pig feed to improve growth rate, feed
conversion ratio, reproductive performance and survival of the animals (NRC, 1998).
However, their use may cause drug residues in foods of animal origin. An alternative
could be the use of natural herbal products such as essential oils abundant in many plant
species. One such plant specie is lemon grass which can grow throughout the year under
tropical conditions. In Thailand, the herb is locally cultivated and used in many recipes
of the Thai kitchen. Its oil is commonly used as a lotion in order to prevent mosquito
bites. Lemon grass oil is a volatile oil which can be extracted directly from fresh lemon
grass using steam extraction. The grass contains 0.035 % essential oil (Malee et al.,
2000). The objective of this study was to asses the effects of lemon grass oil, an
essential oil, as a feed additive in weanling pigs using their productive performance and
faecal scores. Faecal scoring is an indirect and qualitative method based on faecal
characteristics especially color and shape that gives an indication of the conditions in
the intestines.
Material and Method
The experiment was conducted at Chiang Mai University. In a completely randomised
design, 28 days old weanling piglets of 7 ± 0.8 kg body weight were randomly
distributed into groups of 6, 4, 5, 4 and 4 animals. Each piglet was housed in an
individual cage and fed with only one of the 5 diets. Diet 1 (Table 1) formulated
according to NRC standards (1998) was the basal diet in all groups. However, diet 2 had
a supplement of 0.75 g tetracycline per kg basal diet, and diets 3, 4 and 5 had
supplements of lemon grass oil at 1, 2.5 and 5 ml/kg basal diet, respectively. Weight
measurements and scores of faecal colour and shape were determined until pigs were 20
± 0.8 kg BW.
Result and Discussion
The results of the experiment are shown in Table 2. The pigs fed basal diet had
significantly higher (p<0.05) average daily feed intake (ADFI) than pigs fed basal diets
containing lemon grass oil at 1 and 2.5 ml/kg diet (diet 3 and 4). There was no
difference (p>0.05) between ADFI of pigs fed basal diet alone and that of pigs fed diet 5
containing 5 ml/kg lemon grass oil. Average daily gain and feed conversion ratio (FCR)
were not significantly different among the groups although the inclusion of lemon grass
oil at 5 ml/kg of diet tended (P>0.05) to improve the FCR. However, Malee et al.
(2000) found improvements in productive performance of weanling pigs fed diets
supplemented with lemon grass oil. Essential oils improve the absorption and utilisation
of nutrients in pigs (Onibala,1999), while some have been reported to enhance the
activity of digestive enzymes and act as antimicrobial agents (Isamel and Pierson, 1990)
to reduce the incidence of diarrhea.
The observation that pigs fed diets 4 and 5 had better faecal scores than pigs fed other
diets (p<0.05) suggests that they had better gut conditions for digestion and absorption.
Normally, a dark color and lump shape of faeces shows normal digestion and
absorbtion. Conversely, a yellow color and loose shape of faeces show a comparably
poorer feed digestion and lower nutrient absorption.
Conclusion
The results suggest that lemon grass oil can substitute tetracycline as feed additive.
Further studies are necessary to confirm the results.
References
Isamel, A.A. and M.D. Pierson.1990. Inhibition of germination outgrowth and
vegetative growth of Clostridium baturinum by spice oils. J. of Feed Protection 53(9): 755-758. Malee, B., D. Petchply, S. Chyratch and C. Sawangwong. 2000. Local Herb. Herb Research Institute, Department of Medical Science, Bangkok. NRC. 1998. Nutrient Requirements of Swine. 10th ed. National Academy Press. Onibala, Jane S.I.T. 1999. Influence of essential oil of spices as feed additives on the performance data and carcass composition in pig nutrition. Master’s thesis, Institute of Animal Physiology and Animal Nutrition. Georg-August-University of Goettingen. Table 1. Composition of basal diet.
Ingredients
g/kg diet
Chemical
g/kg diet
Composition


Table 2. Growth performances and faecal score of weanling pig fed with experimental
Control Basal diet supplemented with
a, b, c, d Means within a row lacking a common superscript letter differ(p<0.05) 1 score index is an average of a degree of shape and color daily collected during feeding trial as follow: shape 1 = very lump and shape 5 = liquid; Color 1= yellow and color 5 = black.

Source: http://www.tropentag.de/2002/abstracts/full/212.pdf