Carcass Traits and Immune Response of Broiler Chickens Fed Dietary L-Carnitine , Coenzyme Q 10 and Ractopamine

This study was conducted to evaluate the effects of coenzyme Q10, L-carnitine and ractopamine supplementation, alone and in combinations, on carcass traits and immune response of broiler chickens. Five hundred and twelve one-day-old Ross 308 male broiler chickens were randomly allocated into eight treatments with four replicates each. A 2×2×2 factorial arrangement was applied, with two levels of coenzyme Q10 (0 and 40 mg/kg), two levels of L-carnitine (0 and 200 mg/kg) and two levels of ractopamine (0 and 10 mg/kg). The birds were reared until day 42 of age under standard conditions. Blood samples were collected at the end of grower and finisher periods from the wing vein. Four birds per group were sacrificed at day 42 of age. Except for carcass yield, other carcass traits were not significantly affected (p>0.05) by different levels of coenzyme Q10, L-carnitine, or ractopamine. Immune response parameters were significantly (p<0.05) different between the treatments. The lowest antibody titers against Newcastle disease virus and relative spleen weight were observed in control group. The results of this study suggest that addition of coenzyme Q10 and L-carnitine to broiler diets has benefit effect on immune response of broiler chickens.


INtRODUCtION
Physiological additives aid the normal development of physiological functions (Hassan et al., 2011).As early as 1963, beta-adrenergic agonists have been used in broiler diets (Cunning, 1963).The dietary administration of the beta-adrenergic agonist ractopamine, a potent growth promoter, has been shown to increase protein accretion and decrease fat deposition in turkeys (Wellenreiter & Tonkinson, 1990).Various beta-adrenergic agonists have been shown to be capable of improving weight gain when added to the feed of domestic species.The feed additive ractopamine is a beta-adrenergic agonist licensed for use in cattle and swine diets by the US Food and Drug Administration in 2003.The positive effects of beta-adrenergic agonists on the performance of meat-producing animals, including poultry, are well documented in several experiments (Yousefi et al., 2011).
Coenzyme Q (2,3-dimethoxy, 5-methyl, 6-polyisoprene parabenzoquinone) is present in all membranes of cell.Ubiquinone or coenzyme Q 10 is a vitamin -like substance which is found in small amounts in a wide variety of foods and is synthesized in all tissues.Ubiquinone is the coenzyme of at least three mitochondrial enzymes (complexes 1, 2 and 3).Mitochondrial enzymes of the oxidative phosphorylation pathway are essential for the production of the high oxidative energy phosphate containing compound, adenosine-tri-phosphate (ATP), upon which all cellular function depend (Ahmad et al., 2010).Coenzyme Q 10 acts as a non-specific stimulant of the immune host defense system.Coenzyme Eila N, Aminafshar M

Carcass Traits and Immune Response of Broiler
Chickens Fed Dietary L-Carnitine, Coenzyme Q 10 and Ractopamine Q 10 has been shown to protect experimental animals against tumor growth and to enhance the immunity to viruses.In a study with eight chronically-ill human patients, the administration of coenzyme Q 10 at 60 mg/day was associated with significant increases in serum levels of immunoglobulin G after 27-98 day of treatment (Folkers, 1982).The results of a study showed that the dietary combination of coenzyme Q 10 and L-carnitine reduce packed cell volume and ascites mortality in broiler (Asadi et al., 2013).
The chemical structure of L-carnitine (ß-hydroxy γ-trimethyl amino butyrate) was elucidated in 1927.Carnitine was synthesized in vivo from lysine and methionine in the kidney and testes (rat), skeletal muscle (sheep), brain (man), and liver in all mammals.During carnitine synthesis, lysine provides the carbon chain and the nitrogen atom, while methionine provides the methyl groups (Arsalan, 2006).The major role of L-carnitine appears to be the transport of longchain fatty acids into the mitochondria for ß-oxidation.In addition to its role in the oxidation of fatty acids, L-carnitine was shown to exhibit immunomodulatory effects.Mast et al. (2000) showed that dietary L-carnitine supplementation increased the production of antigen-specific immunoglobulin G in broiler chickens.This amine is present at high concentrations in the lymphocytes, where it is involved in apoptosis inhibition and in the proliferative response to mitogens (Desimone et al., 1994).
The aim of this experiment was to investigate the effects of the dietary supplementation of coenzyme Q 10 , L-carnitine and ractopamine, individually and in combination, on the carcass traits and immune parameters of broiler chickens.
The diets were based on corn and soybean meal, formulated according to the recommendations of the Ross 308 manual, and offered as mash.The feedstuffs and nutrient composition of the starter (days 1-10), grower (days 11-24), and finisher (days 25-42) are presented in Table 1.Birds were housed in an environmentally-controlled room.House temperature was initially maintained at 32 ˚C and then gradually reduced to 23-24 ˚C for the remaining of the experimental period.Air relative humidity was maintained at 65%.A continuous lighting program was applied for the first three days, after which a 23-h light: 1-h dark cycle was provided.Feed and fresh water were available ad libitum.
Feed was withdrawn three hours before slaughter.At the end of experiment (6 weeks), one bird per pen, which body weight was nearest to the average in the pen, was sacrificed by severing the jugular vein Carcass and edible parts, including heart and liver, yields were calculated relative to body weight at sacrifice.
Birds were individually vaccinated using a commercial Newcastle disease virus (NDV) vaccine on days 8 (B 1 ) and 18 (LaSota).Blood samples of one bird per replicate were collected from the wing vein at days 24 and 42 of Eila N, Aminafshar M

Carcass Traits and Immune Response of Broiler
Chickens Fed Dietary L-Carnitine, Coenzyme Q 10 and Ractopamine age.Sera were separated and stored at -20 ˚C before analysis.Antibody titers against Newcastle disease were measured by hemagglutination-inhibition test (Allan and Gough, 1974).Antibody titer values were log 2 (x) transformed before statistical analysis.
Blood samples were collected from the wing vein in sterile test tubes containing anticoagulant (sodium citrate) at the end of experimental period to determine white blood cell count (WBC) and the absolute numbers of each leukocyte type.
Statistical analysis was performed using SPSS 20 for Windows.Firstly, the normality of data distribution was verified using the Kolmogorov-Smirnov test.Data were subjected to analysis of variance using the GLM (general linear model) procedure, means were compared by Duncan's Multiple Range test.Statistical significance was accepted when p<0.05.

RESULtS AND DISCUSSION
The effect of coenzyme Q 10, ractopamine, and L-carnitine on carcass traits are presented in Table 2.As shown in Table 2, the dietary supplementation of these compounds had no effect on breast yield, thigh yield, or heart and liver percentages.This finding was in agreement with report of Farhangfar et al. (2010), who did not detect any effect of coenzyme Q 10 at level of 20mg/kg of feed on carcass, thighs, or breast yields.Honda et al. (2010) also showed that liver weight was not influenced by coenzyme Q 10 supplementation.In agreement with our findings, Akbariazad et al. (2010) observed that the use of L-carnitine in broiler chicks had no significant effects on carcass traits.In contrast, Kidd et al. (2009) verified a significant increase in the leg yield of broilers fed L-carnitine.These differences probably are related to the level of L-carnitine supplementation, broiler sex, and composition of experimental diet.
Among the eight treatments, the control broilers presented the lowest carcass yield, which was significantly relative to treatment 5 (ractopamine + coenzyme Q 10 ), treatment 6 (ractopamine+ L-carnitine), and treatment 8 (ractopamine + coenzyme Q 10 + L-carnitine).The higher carcass observed in the present study is consistent with the findings of Moslemipur et al. (2012), with the addition of terbutaline, a beta-adrenergic antagonist to broiler diets.Differences in broiler sex, type and level of beta-adrenergic agonist, and diet compositions may explain the differences between the results obtained in our experiment and in other studies.
Newcastle antibody titers determined at days 24 and 42 of age, white blood cell (WBC) counts, spleen relative weight, and heterophil to lymphocyte ratio are summarized in Table 3.The results showed that WBC counts were not affected by ractopamine, coenzyme Q 10 or L-carnitine supplementation.These results are in agreement with an earlier report by Akbariazad et al. (2010), who showed that the dietary inclusion of L-carnitine at levels of 125 and 250 ppm had no significant effect on the WBC count of broilers.On the other hand, Karadeniz et al. (2008) found an  Values with different superscripts in the same column for each section are significantly different (p<0.05). 1 WBC, White blood cell.

Table 1 -
Composition and nutrient levels of the starter, grower and finisher diets

Table 2 -
Effects of supplemental dietary ractopamine, coenzymeQ 10 and L-carnitine on carcass traits of broiler chickens.(mean ± standard deviation) Values with different superscripts in the same column for each section are significantly different (p<0.05).

Table 3 -
Effects of supplemental dietary ractopamine, coenzymeQ 10 and L-carnitine on immune response of broiler chickens.(mean ± standard deviation)