ay in herGrowth Performance, Feed Utilization, Carcass Traits, Immune Response and Antioxidant Status of Growing Rabbits Supplemented with Peppermint and Basil Essential Oils.ABSTRACT The effects of peppermint (Mentha piperita) and/or basil (Ocimum basilicum) essential oil supplementation on the productive performance of rabbits were evaluated. Forty-eight V-line rabbits at five
weeks of age were randomly divided into four equal groups. The control group
(1st group) was fed a basal diet without supplementation. The 2nd, 3rd, and 4th groups were fed a basal diet supplemented with
400 mg of peppermint essential oil (PO), 400 mg of basil essential oil (BO), and 200 mg of PO plus 200 mg of BO/kg diet (essential oil blend; EOB), respectively. The results indicated that the significant (P ≤ 0.01) decrease
in the feed intake (FI) was observed in the groups fed
PO and EOB compared with the control group. The essential oil blend had the most
significant (P ≤ 0.01) effect on the feed conversion ratio (FCR).
Additionally, dietary supplementation with PO, BO and EOB significantly (P ≤ 0.01) increased the serum total antioxidant capacity
compared with the control group. However, the dietary addition of PO, BO and EOB did not significantly
affect the
final live body weight and average daily gain,
nutrient digestibility, nutritive values, most carcass traits, haematological parameters, immunoglobulin proteins (IgG and IgM) and serum lipid profiles
compared with the control group measurements. In conclusion, the blend of peppermint and
basil essential oils has the potential for use as a feed additive for growing rabbits to improve the FI, FCR and antioxidant status without any detrimental
effects on the growth performance, nutrient digestibility, carcass traits and
immunity. Keywords: Essential oils – Growth performance – Immune response – Antioxidant status – Growing rabbits. 1 2 3 4 5 26 Introduction
Chemical feed additives, such as antibiotics and hormones, have been commonly used
for several decades (Rice and Straw, 1996). However, the
use of antibiotics as feed additives in animal diets is banned in the EU
due to their side effects, the potential for the appearance of residues in animal-derived foods (Russell and Houlihan, 2003) and the possible evolution of antibiotic-resistant bacteria, which pose great risks to human health (Benchaar et al., 2008). Subsequently, increasing public health concerns and demands for food safety and high-quality white meat has promoted a scientific drive to identify safe and natural alternatives (Cowan, 1999). The herbal supplements secondary compounds, such as essential oils (EOs), saponins, and tannins, have become a primary
source of feed additives and antioxidants to improve general health conditions in humans and animals.
Therefore,
many researchers have directed their efforts to evaluate the use of herbal
and plant secondary compounds
as feed additives for rabbits and poultry,
which represent
good, fast and cheap sources of white meat. Moreover, herbal feed additives
have been found to improve
the average daily gain (ADG) and feed conversion ratio (FCR), reduce the
mortality and increase the viability of rabbits (El-Kholy et al., 2012 and Zeweil et al., 2013). Peppermint (Mentha piperita) is a perennial herb belonging to the Lamiaceae family. The oil of M. piperita contains 1
,8-cineole, dihydrocavone, limonene, phytol, linalool, thymol, carveol, piperitenone, and eugenol
as the primary components (Dorman
et al., 2003 and Mkaddem et al., 2009 and Pudpila et al., 2011). Peppermint leaves and
oil were used in ancient Greek, Roman, and Egyptian folk medicine and as flavouring agents and have been used in cosmetic and pharmaceutical products worldwide. Moreover, peppermint oil is used to treat respiratory disorders (Nishino et al., 1997), digestive complaints (Blumenthal, 1998), menstrual cramps (Foster and Tyler, 1999), neuralgia, myalgia, headaches, migraines and chicken pox (Blumenthal, 1998). Peppermint essential oil (PO) also has an antimicrobial effect
(Trombetta et al., 2005 and Pramila et al., 2012), a hepato-protective effect
due to its antioxidant content and free radical scavenger properties (Khalil et al., 2015) and
beneficial effects on some blood biochemical parameters of chicks reared under heat stress conditions (Akbari and Torki,
2014). Furthermore, (Emami et al., 2012) concluded that PO at a dose of 200 or 400 mg/kg dry matter diet for chicks could be an effective alternative to an antibiotic (Virginiamycin®). However,
studies on the effect of peppermint as
an antibiotic growth promoter alternative for the growth
performance and digestibility of broilers are rare, and the results have been controversial (Akbari and
Torki, 2014 and Ahmed et al., 2016 and Arab Ameri
et al., 2016). Basil (Ocimum basilicum), which is also called sweet
or garden basil, belongs to the Lamiaceae family and is dispersed throughout the Mediterranean region (Abbas, 2010). The
major components of the oil of various varieties of O. basilicum
are
methyl chavicol, linalool, methyl cinnamate, methyl eugenol, eugenol and geraniol
(Lachowicz et al., 1997). In folk medicine,
the leaves and flowering tops of sweet basil were used as a carminative, galactogogue, stomachic and
antispasmodic (Sajjadi, 2006). Moreover, basil essential oil (BO) is used as an antimicrobial and antioxidant agent and has antifungal activity (Kocić- Tanackov et al., 2011). Furthermore,
basil aqueous extract has a beneficial effect on deltamethrin-induced nephrotoxicity in albino rats
(Sakr and Al-Amoudi, 2012), and treatment with basil aqueous extract leads to improvement in histological, morphometric and immuno-histochemical changes in rats with cadmium-induced testicular toxicity (Sakr and Nooh, 2013). Several
studies have also been conducted on the effects of dietary EOs as individual oils or combinations of oils on the growth performances of poultry with varied and conflicting results. Although some reports
demonstrated that EOs improve animal performance
(Brenes and Roura, 2010 and Bozkurt et al., 2012), other studies have reported that
these additives are ineffective
(Lee et al., 2003 and Botsoglou et al., 2004).
Moreover, EOs can promote the
production of digestive secretions, stimulate blood circulation, reduce levels of pathogenic bacteria, have antioxidant properties and may reform immune status (Brenes and Roura, 2010
and Zeng et al., 2015). The widespread use of EOs from peppermint and basil in traditional medicines and their abundant beneficial effects on the mammalian digestive and immune systems inspired us to explore their potential biological activities in rabbits. The aim of the
present study was to investigate the effects of PO, BO and EOB on the growth performance,
carcass traits, haematology, serum biochemistry, and antioxidant and immune status
of growing rabbits. MATERIALS AND METHODS
Experimental animals, diets and management Forty-eight growing V-line rabbits of both sexes
at five weeks of age with initial live body weight (BW) of
704.9±67.9 g were used. The rabbits
were randomly distributed into four experimental groups with 12 rabbits each. Each treatment was additionally sub-divided into 4 replicates
of 3 rabbits. The
rabbits were housed in wire floor batteries that were 45 x 36 x 36 cm in size and fed experimental diets for
eight weeks through 13 weeks of age during the summer season (July to September) of 2016.
All animals were maintained under similar hygienic conditions. The rabbits were housed in a well-ventilated block building. Fresh air was circulated in the building using exhaust fans. The
rabbits were
maintained under a 16-h light and 8 -h dark cycle.
The
incidence of dangerous diseases was largely avoided, and the rabbits were never treated with any type of systematic vaccination or medication.
Four experimental groups were designed. The 1st group
was fed the basal diet free of additives and served as the control group. The 2nd and 3rd groups were fed the basal diet supplemented with
PO and BO, respectively, at a dose of 400 mg/kg diet. The 4th group received the
basal diet supplemented with a combination of PO and
BO at a dose of 200 mg of each/kg diet (essential oil blend, EOB). Fresh water was automatically accessible constantly
through stainless steel nipples for each cage. The experimental diets were offered to the rabbits ad libitum. The
basal experimental
diet was formulated to meet all necessary nutrient requirements for growing rabbits according to NRC (1977). The composition and chemical analysis of the basal experimental diet are presented in Table 1.
Individual live
body weight and FI were recorded weekly. The average daily gain
was calculated on a group basis as follows: ADG = (final live BW – initial live BW during a certain period) / number of days for this period. Additionally, the FCR was calculated on a group basis as follows: FCR = feed consumed (g) during a certain period/body weight gain (g) during the same period. (1) Digestibility trial At 13 weeks of age, 16 male rabbits (four rabbits
from each treatment) were randomly selected after termination of the fattening trial.
Rabbits within each treatment were housed separately in metabolic cages that enabled separation of faeces and urine. The collection period was five days. During the collection period, the total excreted faeces were collected from each rabbit daily in buckets before offering the morning meal and weighing. 87 88 89 114 Representative samples (10%) of the total quantities of faeces for each rabbit were
oven- dried daily at 70 °C for 48 h to determine total the DM
of the faeces and to calculate the quantities of faeces on a DM basis.
At the end of the collection period, the faecal samples from each rabbit were mixed thoroughly, and
representative samples (10%) of the mixtures were
ground through a 1-mm screen on a Wiley mill
grinder and
then stored frozen at -20°C prior to the chemical analysis. Representative samples of the
offered feed and the faeces of each rabbit were chemically analysed to determine the
DM, crude protein (CP), ether extract (EE), crude fibre (CF) and ash according to the AOAC (2006) methods. The nitrogen- free extract (NFE) was
determined based on the difference.
Nutritive values in terms of the total digestible nutrients (TDN, %) and digestible crude protein (DCP, %) were
calculated using classic formulas (Cunha and Cheeke, 2012). Carcass characteristics
At the end of the growing period, six rabbits were selected randomly from each treatment group for
carcass evaluations. The
rabbits were fasted with a free water supply for 12 h before slaughter.
The rabbits were weighed pre-slaughter, slaughtered for complete depletion, skinned, and eviscerated. The dressed carcass free from any internal organs was weighed (hot carcass weight without the head), and then the cold carcass without the head was weighed. The hot eviscerated carcass included the liver, heart and kidney. The
carcass yields were calculated as a percentage of the pre-slaughter live BWs of the rabbits. Additionally, the percentages of
the total edible parts, non-edible parts and giblets were calculated as follows: Giblets% = kidney% + heart% + liver%. (2) Total edible parts% = hot carcass% + kidney% + heart% + liver%. (3) Non-edible parts% = 100 – total edible parts%. (4) Haematological study Before slaughter, a six-mL
blood sample was taken from the ear vein with a sterile syringe.
Three mL of blood was added to a Bijon bottle containing ethylenediaminetetraacetic acid (EDTA) as an anticoagulant for the haematological assay. The remaining three mL of the blood sample was placed into a sterile vacutainer tube without an anticoagulant for the serum biochemical analysis. The haemoglobin (Hb) concentration was estimated using the cyanomethe-myoglobin method according to Eilers (1967). Wintrobe haematocrit tubes
were used to determine the packed cell volume (PCV, %). The blood was centrifuged for 20 minutes at 4000 rpm, and then the PCV was obtained using the PCV reading on the
graduated haematocrit tubes. Red blood cells (RBCs) were counted manually using a standard Neubauer cell counting chamber after diluting the blood samples 200-fold with a diluting fluid (10% sodium sulphate, 2% sodium chloride and 1% mercuric chloride solution) (Sastry, 1985). White blood cells (WBCs) were counted manually using a standard Neubauer cell counting chamber after diluting the blood samples 20-fold
with a diluting fluid (1. 5% glacial acetic acid solution and a few crystals of
gentian violet) according to the method of Sastry (1985). The differential leucocytic count was determined by preparing a blood film
fixed in methyl alcohol for 3-5 min and then stained with Giemsa’ s stain for
20 minutes, followed by rinsing under a slow water current and gentle drying between two filter papers. A stained 131 141 142 143 144 blood sample was examined using an oil immersion lens according to the method of Lucky (1977). The percentage of each cell type was calculated
according to the method of Schalm et al. (1986). Serum
lipid profile Total lipids
were estimated by reaction with sulphuric and phosphoric acids and vanillin to form a pink chromophore (Zollner and Kirsch, 1962). Triglycerides were measured colorimetrically using the quadruple enzymatic reaction (Fossati and Prencipe, 1982).
Cholesterol was
determined after enzymatic hydrolysis and oxidation as described by Allain et al. (1974).
High-density lipoprotein (HDL) was determined according to the
methods of
Grove (1979). Low-density lipoprotein (LDL) was determined using the following calculation
according to Warnick et al. (1983): LDL = cholesterol – (HDL + VLDL).
Very low-density lipoprotein (VLDL) was calculated by dividing the value of TG by a factor of 5 according to the method of Warnick et al. (1983).
Immune response and antioxidant status The serum IgG and IgM concentrations were determined using the ELISA technique described by Engvall and Perlmann (1972). Moreover, the
total antioxidant capacity (TAC) was assayed using the method of
Cao et al.
(1995). Briefly, the total antioxidant capacity was measured by the reaction of an antioxidant in 0.02 mL of homogenate with 0.5 mL of hydrogen peroxide
(H2O2) after incubation for 10 min at 37°C.
The antioxidants in the sample eliminated a certain amount of the provided H2O2. The residual H2O2 was determined colorimetrically by an enzymatic reaction that involved the conversion of 3,5-dichloro-2- hydroxybenzene sulphonate into a coloured product that was
assessed at 505 nm. The serum malondialdehyde (MDA) level was
measured according to the method described by Jain (1988). The principle of the method was based on spectrophotometric measurement of the colour that occurred during the reaction of thiobarbituric acid with MDA. The thiobarbituric acid reactive substances (TBARS) concentration was calculated based on the absorbance coefficient of the malondialdehyde–thiobarbituric acid complex and was expressed in nmol/mL. The MDA Bis (dimethyl acetal )–TBA (thiobarbituric acid) complex was used
as a standard. Statistical analyses The results are expressed as the mean ± SE.
All data were analysed in a completely randomized design
with
ANOVA using the SPSS (Standard Version 17.0 SPSS Inc. Chicago, Illinois).
Significant differences between means were detected using Duncan’s multiple range test (Duncan, 1955). The
following model was used: Yi = μ + ai + ei where Yi is the experimental observation, μ is the overall mean, ai is the treatment effect, and ei is the random error. RESULTS Growth
performance Table 2 shows the effect of PO, BO and EOB
supplementation on the growth performance of growing V -line rabbits.
The different supplementations did not significantly influence the final BW and ADG of the V-line growing rabbits during the feeding period compared with those in the
control group. The feed intake decreased significantly (P ≤ 0.01) in the PO and EOB groups compared with the BO and control
groups. The decrease in FI 169 195 196 197 198 199 200 201 202 203 204 205 reached 9.2% and 11.8%
in the PO and EOB groups, respectively, compared with the intake in the control group.
The feed conversion ratio improved significantly in the EOB supplemented group; however, the other treatments did not significantly affect FCR
compared with the control group. Digestion efficiency Table 3 shows the effects of
the different supplementations on the nutrient digestibility. The NFE digestibility
increased significantly (P ≤ 0.05) in the groups fed the PO and BO compared with the EOB group.
However, the effect on this trait was not significant for the different treatments
compared with that of the control group. Moreover, the effect of the
different supplementations was not significant on the
DM, OM, CP, EE and CF digestibility compared with the
effect on the control group. Clearly, non-significant improvements in nutritive values for TDN and DCP occurred in all
experimental groups compared with those of the control group. Carcass traits Table 4
presents the effects of the PO, BO and EOB supplementation on the carcass characteristics. No significant differences were found in the percentages of the cold and hot carcasses, the total edible and non-edible parts, the liver and giblets among the different treatment groups. However, the kidneys percentage
decreased significantly (P ≤ 0.01) in all experimental groups compared with that of the control group.
Additionally, the heart percentage decreased significantly in the group treated with the PO
compared with the control group. Haematological parameters The results are presented in Table 5 depict changes in
the haematological parameters of growing rabbits treated with the PO, BO and their combination. The Hb concentration, PCV value, RBC and WBC counts, and WBC differential percentages did not influence by the different experimental diets when compared with the control group values. Serum lipid profile, immune response and antioxidant status The
data in Table 6 show the effects of PO, BO and
EOB on the serum lipid profile, immune response and antioxidant status.
In the present study, the different treatments had a non -significant effect on the
blood serum total lipid, triglyceride, cholesterol, HDL, LDL and VLDL levels
compared with those of the control group. However, the
PO, BO and EOB supplementation induced numerical improvements in the serum IgG and IgM
compared with the control group values. Moreover, the
data showed that growing rabbits reared through the Egyptian summer season exhibited
a significant decrease (P ≤ 0. 001) in the serum
TAC based on the results obtained for the control group, whereas the PO, BO and EOB supplementation appeared to significantly (P ≤ 0.01) antagonize the effect of the high-temperature summer season. The serum MDA concentration decreased (P ≥ 0.05) with the essential oil treatments compared with that of the control group. 215 232 233 234 235 236 DISCUSSION Our results demonstrated many different effects of the M. piperita and O. basilicum EOs and their combination when administered with the diet of growing rabbits. The final BW and ADG of the V-line growing rabbits during the feeding period did not significantly influence by the different supplementations compared with those of the
control group. The feed intake decreased significantly (P ≤ 0.01) in the PO and EOB groups compared with the BO and control group values. The feed
conversion ratio improved significantly in the EOB supplemented group; however, the other treatments did not significantly affect the FCR compared with that of the control group.
In accordance with the present results, (Demir et al. (2008) and Ashayerizadeh et al. (2009) and Toghyani et al.
(2010)) found no effects on the growth
performance of broilers fed diets supplemented with
1 g/kg of mint powder (M. spicata),
1 g/kg of wild mint (M. longifolia),
and
4 or 8 g/kg of peppermint.
Moreover, Akbari and Torki (2014) showed that the average BW, ADG, and daily FI in female broiler chicks did not significantly affect by dietary supplementation with PO. In contrast to the above findings Emami et al. (2012) showed that the FCR tended to improve (P = 0.039) with dietary supplementation with the PO at a dose of 200 mg
/kg of DM in the diet of chicks compared with the FCR of the
control group birds. Recently, Arab Ameri et al. (2016) reported that supplementation with peppermint powder (1%) resulted in a reduced ADG in birds; however, increasing peppermint powder supplementation to 2% resulted in a higher ADG at 21 days
of age compared with that of birds fed the basal diet. Regarding the
effect of BO
on the growth performance, the present
results agreed with those of Riyazi et al. (2015), who indicated that
supplementation with the BO in the starter and grower diets of broilers had a non-significant effect on the ADG, FI and FCR. However, dietary supplementation with basil leaves and seeds had a beneficial effect on the FI, ADG and FCR
(Abbas, 2010 and Osman et al., 2010 and Onwurah et al., 2011).
Moreover, the final BW, FI and ADG of finishing broilers increased significantly with supplementation with basil leaf extract at doses of 100-300 g/mL (Bo and Ekwe, 2012). Moreover, the EOB presented a synergetic effect on growth with
supplementation of bird diets with a blend of essential oils.
; Mathlouthi et al. (2012); Khattak et al. (2013) found that BW and weight gain
(P < 0.05) and the feed to gain ratio increased (P < 0.05)
following supplementation with a blend of essential oils in growing birds compared with the control group values Notably, animals face many difficulties in accessing the supply of herbs due to the tastes and odours emanated by the active substances contained in the plants, which inhibit intake by animals. Thus, some herbs may be barely appetizing (Jugl-Chizzola et al., 2006). Generally, deterioration of overall performance with the addition of EOs may be associated with an increase in the
villus height: crypt depth ratio in the duodenum of birds,
which consequently can contribute to a lack of nutrient absorption and elevated secretion in the gastrointestinal tract (Xu
et al., 2003). Our results showed that the PO, BO and
EOB did not have deleterious effects on the nutrient digestibility and the nutritive values.
These results are consistent with those presented by Khempaka et al. (2013), who showed that experimental diets containing
0.5– 2.0% dried peppermint had no adverse
effects on the DM, OM and CF digestibility and the nitrogen retention compared with the control
diet.
In contrast, Emami et al. (2012) found that the CP digestibility
increased significantly (P ≤ 0.01) by supplementation with the PO
at a dose of 400 mg/kg
in a broiler diet. However, information concerning the effects of basil on the nutrient digestibility and the nitrogen balance is rare. The results indicated no significant differences in the percentages of the cold and hot carcasses, total edible and non-edible parts, liver and giblets as a result of the different treatments. However, the percentage of the kidneys
decreased significantly (P ≤ 0.01) in all experimental groups compared with the percentage in the control group.
Additionally, the percentage of the heart decreased significantly in the group treated with the PO
compared with the percentage in the control group. In accordance with the present results,
Khempaka et al. (2013) indicated that
the percentages of eviscerated carcasses and giblets of broilers fed
dried peppermint-containing diets (0.5-2%) were similar
to those in the control group. In contrast, dietary supplementation
with peppermint resulted in a decreasing trend in the carcass percentages (P ≤ 0.118) of growing Japanese quail (Mehri et al., 2015a). The effects of BO on the carcass characteristics
in the present study were consistent with the results of
Abbas (2010), who reported that dietary supplementation
with 3 g/kg of basil seed
did not influence the organ weights and carcass characteristics in broilers. Additionally, the yields of the carcass and the
fresh and relative weights of the gizzard, thigh, breast, heart and liver of broilers at 42 days of age did not affect by the dietary
BO at dose of 200 ppm (Riyazi et al., 2015), and Gurbuz and Ismael (2016) found that feed additive with peppermint and basil had no significant effects on the carcass, carcass yield and abdominal fat. The haematological parameters did not influence by the different experimental diets
compared with the control group. These current findings are consistent with those
of Bo and Ekwe (2012), who found that treatment with basil leaf extract (100-300 g/mL) did not affect the haematological indices of finishing broilers. However, the
present results are in contrast to those of Osman et al. (2010), who indicated that
supplementation with sweet basil increased the RBC and lymphocyte counts
compared with those of the control group. Saha et al. (2012) reported that the protective effect
observed for the methanolic extract of basil leaf against benzene-induced haematotoxicity in Swiss albino mice, which was attributed to the monoterpenes contained in the extract, such as geraniol, citral, and eugenol might be associated with this activity.
In the present study, the effect of different treatments on the
serum lipid profile levels did not significantly differ from the levels detected for the control group. These results were consistent with those of Akbari and Torki (2014), who showed that the serum total cholesterol, HDL and LDL levels in female broiler chicks did not affect by dietary supplementation with the PO. However,
the results of Ghazaghi et al. (2014) disagreed with the present results and showed that
dietary spearmint (24.6 g/kg) supplementation
resulted in a decrease in the LDL concentration in
growing quail. Additionally, Mehri et al. (2015b) found that the triglyceride, total cholesterol and LDL concentrations decreased in birds that received dietary
peppermint at the rate of 20–30 g/kg diet
compared with those of the control group, whereas the HDL level
increased (P≤0.001). Supplementation with the PO, BO and EOB induced numerical improvements in IgG and IgM levels in a comparison of the control group. Similar to our results,
no changes occurred in the serum antibody response against Newcastle virus
vaccine in broilers with dietary supplementation of 150 g/kg of mint and
4 and 8 g/kg of peppermint
(Al-Ankari
et al., 2004 and Toghyani et al., 2010)
or drinking water supplemented with 2, 4 or 6 mL/L of alcohol extract of peppermint (Abdulkarimi and Abdullahzadeh, 2011). Recently, Fallah et al. (2013) demonstrated that the antibody titre against NDV did not differ between the M. piperita extract and control groups. However, our results disagreed with those of Awaad
et al. (2010), who found that the addition of 0.25 mL of a eucalyptus and
PO blend/L of drinking water boosted the antibody titre against the Newcastle virus vaccine in chickens compared with the control group titre. Additionally, Emami et al. (2012) reported that feeding the PO at a dose of 400 mg/kg of diet led to a lower secondary antibody response against sheep red blood cells (SRBCs) in broilers than the response measured for the control group. Moreover, Mehri et al. (2015b) stated that growing quail fed diets supplemented with peppermint showed an increase in humoral responses,
including antibody production against primary and secondary SRBCs (P = 0.001 and 0.030, respectively) and Newcastle disease virus (P = 0.001),
compared with the control group responses. Dashputre and
Naikwade (2010) found 8 that basil leaf aqueous and ethanolic extracts resulted in a marked increase in circulating antibody titres in response to SRBCs in mice supplemented with 400 mg/kg/day. Similarly, feeding experimental diets inclusive of either rosemary, marjoram or sweet basil improved the immune status in broilers, as reflected by the enzyme-linked immunosorbent assay and haemagglutination inhibition titres
compared with those of the control group (Osman et al., 2010). The
data showed that growing rabbits reared through the Egyptian summer season exhibited
a significant decrease (P ≤ 0. 001) in the serum
TAC based on the results obtained for the control group; however, supplementation with the PO, BO and EOB appeared to significantly (P ≤ 0.01) antagonize the effect of the high-temperature summer season. The serum MDA concentration decreased (P ≥ 0.05) with the essential oil treatment compared with the concentration of the control group. However, Upton (2003) demonstrated that stresses, such as heat stress, led to the excessive production of free radicals, which reduced the antioxidant capacity. Moreover, Newsholme et al. (2003) reported that heat stress had an effect on the sympathetic nervous system that resulted in the release of catecholamine, which
caused an increase in the free radical content in the blood and
body tissues. Additionally, Lin et al. (2000) indicated that free radicals gave rise to peroxidation in cells and thereby increased the lipo-peroxide concentrations in the tissues and that the increase in lipo-peroxide led to reduced glutathione peroxidase, superoxide dismutase and catalase enzyme activity. Under these conditions, Aryaeian et al. (2011) demonstrated that the plasma concentrations of some vitamins and minerals involved in the antioxidant system decreased and that several active oxygen radicals increased. Therefore, antioxidants, such as those found in herbs and vitamins, reduce heat stress and prevent free radical damage to the body and thus protect cells from oxidative damage. Peppermint and basil oils or their combination
had beneficial results on the antioxidant properties in rabbits aged
13 weeks. The rapid increase in the growth rate- induced oxidative stress occurred via
the function of cortisol hormones in response to metabolic adaptation during stress. Regarding the chemical
compositions, the PO, BO and EOB are
composed of phenolic and flavonoid compounds, which have been confirmed to possess strong antioxidant activities. Additionally, Olennikov and Tankhaeva (2010) found that M. piperita
included
approximately 2.70 to 5.52% phenolic compounds and 3.02 to 6.32% flavonoid compounds. The EOs of M. piperita, M. longifolia, and M. aquatic are also mainly responsible for the antioxidant potential
of these plants (Tachakittirungrod et al., 2007 and Baliga and Rao, 2010). The components of PO that are associated with the
antioxidant properties are 1,8-cineole, dihydrocavone, limonene, phytol, linalool, thymol, carveol, piperitenone, and eugenol
(Dorman
et al., 2003 and Mkaddem et al., 2009 and Pudpila et al., 2011). Moreover, Khempaka et al.
(2013) reported that supplementation with dried peppermint at a dose of 2% significantly (P ≤ 0.05) reduced the TBARS value
in the sera of broilers at 42 d of age
compared with the values obtained with the other treatments (0, 0.5 and 1%). Basil shows
antioxidant activity due to its aromatic compounds and phenolic acids
(Hussain
et al., 2008); the major phenolics in basil are phenolic acids and flavonol-glycosides
(Kivilompolo and Hyötyläinen, 2007). Additionally, the
antioxidant effect of phenolics leads to the absorption and neutralization of free radicals
(Asami et al., 2003). The primary constituents of sweet basil oil are linalool, isoanethole and eugenol, which have
shown appreciable antioxidant activities that are comparable with those of α-tocopherol
(Orhan et al., 2008). Therefore, the BO
can overcome lornoxicam (LOR)-induced hepatic damage by attenuating oxidative stress. Remarkably,
inhibition of butyrylcholinesterase (BChE) activity
during co-administration of LOR with the BO supported this hypothesis
(Dasgupta and De, 2007). These ameliorations may be attributed to the radical-scavenging and antioxidant properties of BO. Additionally, Politeo et al. (2007) attributed the potential antioxidant properties of basil
to free volatile aglycones based on two different methods (the 2,2- diphenyl-1-picrylhydrazyl radical scavenging method and the ferric reducing/antioxidant power assay)
in a comparison of the antioxidant properties of EOs with the well-known antioxidant butylated hydroxytoluene. CONCLUSIONS 405 In conclusion, the mixture of peppermint and basil essential oils has the potential for use
as a feed additive for growing rabbits because it has beneficial
effects on the FI, FCR and antioxidant properties without
any detrimental effects on the growth performance, immunity, carcass or digestibility.
Clearly, further research on the addition of different doses of peppermint
and basil essential oils and their combination
is needed to verify whether these EOs have beneficial effects on the growth performance, immunity, carcass and digestibility.
ACKNOWLEDGMENTS The authors gratefully acknowledge all staff of the Animal and Fish Production Department, Faculty of Agriculture (Saba Basha), Alexandria University, Egypt, for their help and support during the
experimental period. 417
Table 1: Ingredients and chemical composition of basal diet fed to growing rabbits.
Ingredients Amount % Ground yellow corn 19.00 Wheat bran 11.00 Barley 17.20
Soybean meal (44%) 15. 00 Berseem hay 33 .00 Molasses 3.00
Di-calcium phosphate 1.00 Sodium chloride (salt) 0.30 Premix1 0.30 Di
-methionine 0.10 L-lysine 0.10 Total 100.
00 Chemical composition (% of DM basis) Dry matter 91.83 Crude protein 18.87 Ether extract 3.33 Crude fiber 13.57 Nitrogen free extract 54.89 Ash 9.34 Organic matter 90.66 DE, Kcal / Kg 2 2502 1premix contained the following vitamins and minerals mixture per kg (g/kg):
Vit A., 2000 .000 IU, Vit E, 10 mg, Vit B1, 400 mg, Vit B2, 1200 mg, Vit B6, 400 mg, Vit B12, 10 mg, Vit D3, 180000 IU, Colin chloride, 240 mg, Pantothenic acid, 400 mg, Niacin, 1000 mg, Folic acid, 1000 mg, Biotin, 40 mg, Manganese, 1700 mg, Zinc, 1400 mg, Iron, 15 mg, Copper, 600 mg, Selenium, 20 mg, Iodine, 40 mg and Magnesium, 8000 mg.
2DE, Kcal / Kg: digestible energy, = 4.36-0.0491×NDF%, whereas NDF %: neutral detergent fiber, = 28.924+0.657× CF%, whereas CF%: crude fiber. Table 2: Effect of diets supplemented with peppermint
and basil essential oils and their combination on the
growth performance of growing rabbits. Items Control PO BO EOB P value Initial BW, g 705.0±66.8 702.08±68.1 705.8±67.4 706.6±69.2 0.999 Final BW, g 2100.0±46.5 2037.9±60.0 2043.8±42.5 2175.8±39.4 0.161 ADG, g/ rabbit/ day 23.42±0.94 21.58±1.13 22.08±0.79 24.58±0.95 0.130 FI, g/ rabbit/ day 116.92a±1.13 106.22b±2.78 111.59ab±3.72 103.10b±2.62 0.015 FCR 4.99a±0.26 4.92a±0.15 5.05a±0.15 4.20b±0.14 0.02 PO: peppermint essential oil supplemented with 400 g/kg diet, BO: basil essential oil supplemented with 400 g/kg diet, EOB: essential oil blend supplemented with 200 g of each oil/kg diet, BW: body weight, ADG: average daily
gain, FI: feed intake, FCR: feed conversion ratio. a-b: Values in the same row with different superscripts differ significantly (P ≤ 0.05).
427 428 429 430 coefficients of nutrient nutritive values of growing rabbits. Items Control PO BO EOB P value Digestion coefficients of nutrient, % DM 67.70±2.98 67.08±6.31 67.73±2.73 65.80±3.74 0.904 OM 78.18±3.25 79.18±2.56 78.88±1.44 81.78±1.82 0.209 CP 66.30±1.60 66.45±1.58 67.25±1.80 66.90±1.92 0.860 EE 69.78±0.97 69.50±2.50 69.85±1.76 70.00±1.83 0.984 CF 33.00±6.94 28.75±4.25 32.48±4.69 27.80±7.54 0.538 NFE 80.75ab±3.44 81.50a±3.55 82.63a±3.97 75.50b±2.93 0.059 Nutritive values, % TDN 64.15±2.05 65.23±1.50 66.35±2.85 62.88±5.29 0.503 DCP 12.51±0.15 12.54±0.15 12.69±0.17 12.62±0.18 0.857 PO: peppermint essential oil supplemented with 400 g/kg diet, BO: basil essential oil supplemented with 400 g/kg diet, EOB: essential oil blend supplemented with 200 g of each oil/kg diet,
DM: dry matter, Om: organic matter, CP: crude protein, EE: ether extract, CF: crude fiber, NFE: nitrogen free extract, TDN: total digestible nutrient, DCP: digestible crude protein.
a-b: Values in the same row with different superscripts differ significantly (P ≤ 0.05). traits of growing rabbits
Items Control PO BO EOB P value Pre-slaughter Weight, g 1943.3c±148.7 2106.7ab±137.8 2068.3bc±49.8 2236.7a±58.8 0.002 Hot carcass, % 48.39±2.62 48.24±6.08 49.18±1.79 51.26±2.46 0.473 Cold carcass, % 46.08±1.90 47.05±5.93 46.67±3.38 49.88±2.25 0.322 Liver, % 2.90±0.72 3.08±0.89 2.48±0.54 3.17±0.50 0.329 Heart, % 0.30ab±0.04 0.24c±0.03 0.25bc±0.01 0.32a±0.06 0.013 Kidneys, % 0.71a±0.07 0.56b±0.07 0.54b±0.07 0.59b±0.02 0.001 Giblets, %1 3.90±0.67 3.88±0.97 3.26±0.59 4.07±0.46 0.233 Total edible parts, %2 52.30±3.16 52.12±6.95 52.44±1.88 55. 32±2.27 0.491 Non-edible Parts, % 3 47.70 ± 3.16 47.88 ± 6.95 47.57 ± 1.88 44.68 ± 2.27 0.492 PO: peppermint essential oil supplemented with 400 g/kg diet, BO: basil essential oil supplemented with 400 g/kg diet, EOB: essential oil blend supplemented with 200 g of each oil/kg diet. 1Giblets % = kidney %+ heart%+liver%. 2Total edible parts % = hot carcass%+ kidney%+ heart%+liver%. 3Non-edible parts% = 100- total edible parts %.
A, b, c: Values in the same row with different superscripts differ significantly (P ≤ 0.05). hematological parameters of
growing rabbits. Items Control PO BO EOB P value Hb, mg/dl 11.10±0.82 11.38±0.25 11.10±0.55 11.05±0.73 0.881 PCV, % 46.68±3.07 46.53±4.16 46.33±0.96 44.90±5.20 0.914 RBCs, 106/mm3 4.93±0.36 5.27±0.41 5.43±0.17 5.20±0.40 0.290 WBCs, 103/mm3 4.73±0.17 4.82±1.01 5.05±1.13 6.23±1.47 0.221 Neutrophils, % 40.50±6.60 43.50±0.57 41.25±8.01 38.00±4.08 0.593 Monocytes, % 3.75±1.50 3.25±0.50 3.25±0.50 3.75±0.95 0.781 Eosinophils, % 4.75±0.95 5.00±0.81 4.75±0.95 5.50±0.57 0.566 Lymphocytes, % 51.00±4.69 48.25±1.26 50.75±6.70 52.75±4.50 0.616 PO: peppermint essential oil supplemented with 400 g/kg diet, BO: basil essential oil supplemented with 400 g/kg diet, EOB: essential oil blend supplemented with 200 g of each oil/kg diet, Hb: hemoglobin, PCV: packed cell volume,
RBCs: red blood cell count, WBCs: white blood cell count.
lipid profile, serum immune response and antioxidant status of growing rabbits. Items Control PO BO EOB P value Total lipids, mg/dl 478.00±115.10 397.50±100.67 408.00±64.46 439.50±93.03 0.473 Triglycerides, mg/dl 82.33±23.11 62.17±16.21 73.67±14.00 72.33±23.83 0.393 Cholesterol, mg/dl 72.67±10.40 66.00±6.57 72.50±15.89 71.67±7.81 0.675 HDL, mg/dl 15.88±6.56 12.62±4.37 13.60±7.17 13.95±6.16 0.828 LDL, mg/dl 10.32±9.52 10.95±5.35 14.17±9.16 14.75±10.61 0.769 VLDL, mg/dl 16.46±4.62 12.43±3.24 14.73±2.80 14.47±4.76 0.393 HDL/LDL ratio 2.41±1.70 1.36±0.63 1.29±0.92 3.29±4.74 0.499 IgG, mg/dl 221.33±45.85 226.17±29.82 259.17±47.42 253.50±46.03 0.341 IgM, mg/dl 51.56±12.57 52.89±13.03 58.65±11.08 64.18±18.75 0.412 TAC, µmol/ml 0.86b±0.06 1.50a±0.11 1.52a±0.19 1.81a±0.20 0.005 MDA, nmol/ml 5.04±0.28 4.23±0.42 4.15±0.25 4.39±0.42 0.314 PO: peppermint essential oil supplemented with 400 g/kg diet, BO: basil essential oil supplemented with 400 g/kg diet, EOB: essential oil blend supplemented with 200 g of each oil/kg diet,
HDL: high density lipoprotein, LDL: low density lipoprotein, VLDL: very
low-density lipoprotein IgG: immunoglobulin G, IgM: immunoglobulin M, TAC: total antioxidant capacity, MDA: malondialdehyde.
a-b: Values in the same row with different superscripts differ significantly (P ≤ 0.05).
460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 الملخص العربي أداء النمو، الاستفادة الغذائية، صفات الذبيحة، الاستجابة المناعية والحالة ضد التأكسدية للأرنب النامية المضاف لها زيوت النعناع والريحان لقد تم تقييم تأثيرات إضافة زيت النعناع و/ او زيت الريحان على الأداء الإنتاجي للأرانب. لقد تم تقسيم 48 ارنب سلالة V line عمر 5 أسابيع عشوائيا الى 4 مجاميع متساوية. المجموعة الأولى (الضابطة) تم تغذيتها على العليقة الأساسية بدون أي إضافات. المجموعة الثانية والثالثة والرابعة تم تغذيتها على العليقة الأساسية مضاف لها 400 ملجم زيت النعناع، 400 ملجم زيت الريحان، 200 ملجم زيت النعناع مع 200 ملحم زيت الريحان/ كجم عليقة (خليط الزيوت الاساسية) على التوالي. انخفض المأكول مع المجموعات التي غذيت زيت النعناع وخليط الزيوت مقارنة بالمجموعة الضابطة. لقد اظهر خليط الزيوت الأساسية تأثير معنوي ) P ≤ 0.01 (على معدل التحول الغذائي. بالإضافة الى ان إضافة زيت النعناع وزيت الريحان وخليط الزيوت الأساسية في العليقة الى زيادة معنوية ) P ≤ 0.01 ( في القدرة المضاد التأكسدية الكلية للسيرم مقارنة بالمجموعة الضابطة. على الرغم من إضافة زيت النعناع وزيت الريحان وخليط الزيوت الأساسية في العليقة لم يؤثر معنويا على وزن الجسم الحي النهائي، معدل الزيادة الوزنية اليومية، معاملات هضم العناصر الغذائية، القيم الغذائية، معظم صفات الذبيحة، قياسات الهيماتولوجية، بروتينات الامينوجلوبيولين وقياسات دهون السيرم مقارنة بالمجموعة الضابطة. ومن هنا يمكن استنتاج ان إضافة الزيوت الأساسية للنعناع والريحان يمكن استخدمها كإضافات غذائية للأرانب النامية لتحسين المأكول ومعدل الحويل الغذائي والحالة المضادة تأكسدية بدون أي تأثيرات سلبية على أداء النمو، معاملات الهضم، صفات الذبيحة والمناعة. 27 Table 3: Effect of peppermint and
basil essential oils and their combination on the
digestion Table 4: Effect of peppermint and
basil essential oils and their combination on the
carcass Table 5: Effect of peppermint and
basil essential oils and their combination on the
Table 6: Effect of peppermint and
basil essential oils and their combination on thee…