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Effects of various quantities of Yucca schidigera powder (Deodorase) added to diets on the performance, some hematological and biochemical blood parameters, and total antioxidant capacity of laying hens

R. ASLAN1*, Y. DUNDAR2, A. ERYAVUZ1, A. BULBUL1, I. KUÇUKKURT2, A.F. FIDAN2 and Z. AKINCI3

Faculty of Veterinary Medicine, University of Afyon Kocatepe, ANS Kampusu, Afyon, Turkey - 1 Department of Physiology. - 2 Department of Biochemistry. - 3 Department of Animal Science. * corresponding author : [email protected]

SUMMARY The aims of this study were to clarify the effects of dietary supplementation with various quantities of Yucca schidigera powder (Deodorase) on some hematological markers, antioxidant capacity and serum and egg cholesterol concentrations in laying hens. Two hundred fifty six, 41 weeks old, laying hens Lohman LB were divided into 4 equal groups: the first group (control) was fed with basal layer diet and Deodorase (100, 150 and 200 ppm) was added to the ration in the 3 other groups. Zootechnical performances (growth, egg production), hematological parameters (erythrocyte, leukocyte and thrombocyte counts, hematocrit, and hemoglobin concentrations) and biochemical markers (glucose, cholesterol, glutathione, malondialdehyde (MDA) and total antioxidant capacity (TAC)) were monitored throughout the 10-week experiment. Total egg productivity increased in groups supplemented with 100 and 150 ppm Deodorase (p < 0.05), whereas elevations of egg weights were noticed in birds receiving 100 and 200 ppm. While all the other parameters were not significantly affected by addition of Deodorase into diets, glycemia and cholesterolemia were lowered and antioxidant capacities were slightly improved: weak increases of plasma glutathione concentrations and TAC were observed particularly in group supplemented by the lowest dose (100 ppm). In conclusion, dietary supplementation of laying hens by 100 ppm Deodorase induced positive effects on egg production, enhanced antioxidant capacities and decreased glycemia and cholesterolemia.

RÉSUMÉ Effets d'une supplémentation alimentaire par différentes quantités de poudre de Yucca schidigera (Déodorase) sur les performances zootechniques, les paramètres hématologiques et biochimiques sanguins et les capacités anti-oxydantes des poules pondeuses. Par R. ARSLAN, Y. DUNDAR, A. ERYAVUZ, A. BULBUL, I. KUÇUKKURT, A.F. FIDAN et Z. AKINCI. L'objectif de cette étude est de déterminer les effets d'une supplémentation alimentaire des poules pondeuses par de la poudre de Yucca schidigera (Déodorase) à différentes doses sur divers marqueurs hématologiques, les capacités anti-oxydantes, et les concentrations de cholestérol dans les sérums et les oeufs. Au total, 256 poules Lohman LB, âgées de 41 semaines, ont été réparties en 4 groupes égaux : le premier (contrôle) a été nourri par un aliment de base spécifique pour poules pondeuses et la Déodorase a été ajoutée à la ration dans les 3 autres groupes aux doses de 100, 150 et 200 ppm. Les performances zootechniques (croissance, production en oeufs), les paramétres hématologiques (numérations en érythrocytes, leucocytes et thrombocytes, hématocrite, hémoglobinémie) et les marqueurs biochimiques (glucose, cholestérol, glutathion, malonedialdéhyde et capacité antioxydante totale) ont été suivis pendant les 10 semaines d'expérimentation. La productivité totale d'oeufs a augmenté dans les groupes supplémentés par 100 et 150 ppm de déodorase (p < 0.05), tandis que des élévations des poids des oeufs ont été constatées chez les oiseaux recevant 100 et 200 ppm. Alors que tous les autres paramètres n'ont pas été significativement modifiés par l'addition de déodorase, la glycémie et la cholestérolémie ont été abaissées et les capacités anti-oxydantes ont été faiblement améliorées: de faibles augmentations des concentrations plasmatiques en glutathion et de la capacité totale anti- oxydante ont été observées principalement dans le groupe supplémenté par la plus faible dose (100 ppm). En conclusion, une supplémentation alimentaire des poules pondeuses par 100 ppm de déodorase a amélioré la production en oeufs, augmenté la capacité anti-oxydante des animaux et diminué la glycémie et la cholestérolémie.

Keywords : Laying hens - deodorase - cholesterol-egg antioxidant capacity.

Mots-clés : Poule pondeuse - déodorase - cholestérol oeuf - capacité anti-oxydante.

Introduction

Saponins, which are considered as anti-nutritional compounds, mainly exist in plants in two forms as triterpenoid and steroidal saponins [22]. The saponins found in clover, commonly used in animal breeding, have been reported to be in triterpenoid form, whereas the saponins of Yucca schidigera plant were in steroidal form [28]. Some researchers have shown that yucca plant has ammonia binding capacity [3], antiprotozoal and antibacterial effects [29].

Physiological activities of yucca extracts would depend on their saponin content [29, 30]. ROWLAND et al. [23], have reported that the addition of 31 or 155 ppm yucca extract into rations of laying hens increased the productivity of eggs and lowered in-coop ammoniac level while the addition of 465 ppm decreased egg productivity. KUTLU et al. [14] have reported that the addition of 120 ppm yucca extract into the ration increased body weight and fodder consumption in chicken bred for meat purposes.

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COOKSON and FEDEROFF [4], have suggested that the hypercholesterolemia occurring in rabbits fed with cholesterol - enriched diets could be prevented by addition of clover flour containing saponin into the rations. In this way, it has been reported that saponins bound cholesterol and lowered its absorption from the digestive tract and therefore reduced blood cholesterol concentrations [18]. It was also suggested that saponins by binding bile acids increase their excretion into feces, leading to amplification of cholesterol catabolism and decrease of blood cholesterol concentrations [25]. Moreover, a recent study demonstrated that saponins presented also anti-inflammatory and antioxidant effects [27]. Today, it is recognized that possible protective effects of plant-origin fodder are based on the antioxidant substances that they contain and that antioxidants protected cells from the destructive effects of natural oxidation reactions. Consequently, supplementation of diets with saponins would lead to increase of zootechnical performances (growth, production and qualities of eggs) in laying hens by improving cholesterol metabolism and antioxidant systems. In this study, the effects of diets supplemented with various amounts of Yucca schidigera powder, which contains high concentrations of saponins, on zootechnical performances, cholesterol metabolism and antioxidant capacities are evaluated in laying hens.

Materials and methods

Two hundred fifty-six, 41 week-old Lohmann LB hens, were obtained from a commercial laying facility. Hens were housed in individual cages (109 x 68 x 39 cm) in controlled environment laying house with 16 h of light and 8 h of darkness and temperature was between 26 and 32°C. The formulation of basal diet is shown in Table I. The basal diet was a typical layer diet containing 17,5% crude protein (CP) and 2750 kcal metabolizable energy (ME/kg) and was calculated to cover or slightly exceed the nutrients requirements recommended by the National Research council [1]. The hens were divided into four groups of 64 hens each. One group was fed with the basal diet alone (control group) and the other were fed with the basal diet supplemented by increased quantities of Yucca schidigera (Deodorase, Alltech) to provide 100, 150, 200 ppm respectively. Each group of hens was further divided into eight subgroups (8 hens in each subgroup). Hens received the experimental diets and water ad libitum for 10 weeks. Body weights were recorded at the beginning and at the end of the study to determine body weight changes. Egg production and mortality were recorded daily, while egg weights and feed consumption were determined weekly. At the 4th and 8th weeks of experiment, blood samples were collected from vena breachialis from 8 birds randomly chosen from each groups. Blood samples collected in heparinised and non-heparinised tubes were centrifuged 1 500g for 15 minutes at 4°C. Plasma was stored frozen at -20°C until analysis. Red blood cells (RBC), haemoglobin status and hematocrit ratio, mean globular volume (VGM), mean corpuscular haemoglobin concentration (CCMH), white blood

Revue Méd. Vét., 2005, 156, 6, 350-355 TABLE 1. -- Chemical compositions of control and experimental diets. 1 Rovimix 121 : Provided per kilogram of diet : vitamin A 4.800 IU ; vitamin D3 1.000. IU ; vitamin E 8 mg ; vitamin K3 1.6 mg ; vitamin B1 1.2 mg ; vitamin B2 2.4 mg ; vitamin B6 2. mg ; vitamin B12 8 mg ; niacin 10.000 mg, Ca-D-Pantotenate 2.4 mg ; folic acid 250 mg ; choline chloride 100.000 mg. 2 Remineral S : Provided per kilogram of diet : Mn 16 mg ; Fe 24 mg ; Zn 2 mg ; Cu 200 mg ; Co 800 mg ; Se 50 mg ; Ca 89.562 mg. 3 Natugrain Blend : Provided per kilogram of diet : Endo-xylanase : 11.000.000 U ; Beta -Glucanase 240.000 U. 4 Natuphos : Provided per kilogram of diet : Phytase 500.000 U ; Crude protein 564.400 ; Ash 94 ; ME 21.00 kcal/kg ; Ca 167 mg ; Total phosphorus 192 mg ; Digestive phosphorus 21.6 mg ; Lysine 21.6 mg ; Methionine 3.3 mg ; Methionine + cystine 14.9 mg.

cell (WBC) and thrombocyte counts, were determined by the methods mentioned in FELDMAN et al. [7]. Blood lipid peroxidation evaluated by measurement of thiobarbituric acid reactive substances (TBARS), was determined according to DRAPER et al. [5], glutathione by the method of BEUTLER et al. [2] and sera TAC according to KORACEVIC et al. [13]. Egg and plasma cholesterol and glucose concentrations were measured by spectrophotometer using commercial kits according to manufacturer instructions (Teco).

STATISTICAL ANALYSIS

The data from all experiments were subjected to one way ANOVA as completely randomized design using the general linear models procedure of SAS software. Significant differences among the means were determined by using Duncan's multiple-range test at p < 0,05.

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Results

Total egg productivity (Table II) significantly increased in groups of laying hens fed with diets supplemented by 100 and 150 ppm Deodorase in comparison to control group (p < 0.05). By contrast, the total egg production significantly decreased in hens receiving 200 ppm in comparison to all other birds (control and treated by 100 and 150 ppm) (p < 0.05) (Table II). Moreover, the drop of productivity was precociously observed since the 4th week (p < 0.05) and persisted during all the duration of experiment (p < 0.05). Egg weights were also significantly enhanced in comparison to control group in birds treated with 100 and 200 ppm Deodorase (p < 0.05), but curiously not in the group treated by 150 ppm of food additive (Table II). Significant transient increases of food consumption were noted in all groups supplemented by Yucca schidigera powder (p < 0.05) during the first period of the study ; whereas food utilization expressed as kg of food / kg of eggs were not significantly modified. But, when food utilization was expressed as kg of food /

dozen of eggs, significant increases were noticed in the group supplemented with the highest dose (p < 0.05) at the 4th week and for all the duration of experiment (Table II). This study has shown that the addition of Yucca schidigera powder into the ration does not have any effect on body weight or survival (Table II). No significant difference for erythrocyte parameters (red blood cell counts, packed cell volume, haemoglobin concentration, mean globular volume and mean corpuscular haemoglobin concentration) was found between groups (Table III). In the same way, thrombocyte and leukocyte counts were not significantly modified by addition of Deodorase into diets, although leukocyte numbers tended to decrease, mainly on the 8th week in the supplemented groups (Table III). Glycemia decreased in laying hens receiving diets enriched by 150 and 200 ppm Deodorase since the 4th week (p < 0.05). Similarly, cholesterolemia tended also to diminish but differences with control group were statistically significant only for hens supplemented by 200 ppm (p < 0.05). On the 8th week, glucose concentrations and cholesterolemia at a

TABLE 2. -- Effects of basal diets supplemented with Yucca schidigera powder (0, 100, 150 and 200 ppm) on performances (egg production, food utilization, growth and survival) in laying hens (Mean ± SEM). a,b,c : Values with different letters show statistically significant differences (P < 0.05). n : Material number Revue Méd. Vét., 2005, 156, 6, 350-355

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TABLE 3. -- Variations of hematological parameters and biochemical markers (glucose, cholesterol) in blood or in egg yolk of laying hens supplemented with various content of Yucca schidigera powder (0, 100, 150, and 200 ppm) during 10 weeks (n=8, Mean ( SEM). a,b,c: Values with different letters show statistically significant differences (P < 0.05).

lesser extend were markedly diminished in all supplemented groups (p < 0.05 for glycemia, p < 0.05 for cholesterolemia in groups supplemented by 150 and 200 ppm) (Table III). By contrast, egg yolk cholesterol concentrations were clearly unaffected by supplementations with Yucca saponins (Table III). Glutathione concentrations were slightly increased in sera of supplemented birds, but the differences with control group were not statistically significant except for the dose of 100 ppm Deodorase at the 4th week (p < 0.05) (Table III). On the 8th week, increases of TAC were noticed in groups receiving 100 and 150 ppm Yucca saponins (p < 0.05), whereas MDA concentrations were comparable between groups for the 2 experimental periods (Table III).

Discussion

Yucca schidigera powder is considered as a natural growth stimulator in cattle and in birds [24, 28]. Its positive effects on zootechnical performances would be related to saponin content [24]. Although GÜCLÜ et al have demonstrated that dietary supplementation by Deodorase does not improve egg qualities in quails [9], KUTLU et al [15] have described positive effects of Yucca saponins on growth in chicken. If low doses (100 to 150 ppm) of Yucca schidigera powder effectively improved egg production in laying hens, higher

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doses (200 to 465) have been reported to induce opposite effects [24]. In agreement with these findings, our study has shown that low doses (100 and 150 ppm) of Deodorase have induced increases of egg productions whereas this performance has been significantly diminished when a higher dose (200 ppm) was added to diets. Egg weights were also enhanced in the groups receiving 100 ppm but not in the group with 150 ppm. Surprisingly, an increase of this parameter was also noticed when the highest dose was used, leading to a significant improvement of the coefficient of food utilization expressed as kg of food/egg dozen. According to previous reports in laying quails [11, 15], food conversion ratio was not modified by the dietary supplementation with Yucca powder. Saponins were previously reported to alter rumen motility [12] and small intestine peristalsis in rats [20]. Consequently, because aliments stayed longer in digestive tract, digestion would be more complete and nutrients would be more assimilated. This fact could lead to a better food conversion ratio expressed as kg of food by kg of body weight in quails [6] and in laying hens supplemented by saponins [24] or to an improvement of performances such as egg production or egg weight. However, in this study, additions of Yucca powder to diets did not modify the body weights of laying hens and did not affect the mortality of birds. These findings are in agreement with previous reports in chickens [14] and in quails [11].

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Although counts of leukocytes tended to decrease in supplemented birds, but not significantly, no significant change of hematological parameters (numbers of erythrocytes and thrombocytes, packed cell volume, and haemoglobin concentrations) was induced by addition of Deodorase into diet, whatever the doses used. These results confirmed previous studies conducted on quails [6, 11]. On the other hand, Yucca powder supplementation significantly affected glycemia and cholesterolemia since the 4th week and the observed decreases were more pronounced during the second period of experiment. Such effects of saponins on plasma glucose [10, 16, 26] and cholesterol [10, 17, 25] concentrations have been already reported in mice. The hypoglycemic action would be due to reduction of the glucose transfer from the stomach to the brush border of small intestine [26]. However, in our study, a significant effect on cholesterolemia was evidenced only for the 2 highest doses (150 and 200 ppm), while KUTLU et al [14] previously showed that cholesterol concentrations were lowered by 120 ppm of Yucca powder in chickens. It is well known that saponins form complexes with steroid structures (sterols and bile acids) [28]. In borders, saponins delivered from food would directly react with dietary cholesterol and / or with bile acids, and inhibit steroid assimilation by forming large structures enable to cross over the brush border. As a consequence, the exogenous supply of cholesterol would be lowered. Moreover, the amplified elimination of bile acids into faeces would lead to enhancement of cholesterol catabolism [17, 25]. Nevertheless, egg yolk cholesterol concentrations of laying hens were not affected by dietary supplementation with Yucca saponins in this study. Similarly, KAYA et al [11] have not observed modifications of the egg chemical composition in quails, whereas KUTLU et al [15] have evidenced that egg cholesterol amounts were reduced by Yucca scidigera powder addition 120 ppm into diets of laying hens. GRIFFIN [8] stated that egg cholesterol quantity was more correlated with VLDL / LDL than with plasma total cholesterol concentrations. Furthermore, POTTER et al [21] have demonstrated that the dietary addition of saponins modified the plasma concentrations of lipoproteins according to the quality of proteins present in rations. They have observed that plasma HDL and LDL concentrations and the ratio LDL/HDL were not modified when saponins were added to soybean proteins, while, only LDL concentrations decreased when saponins were added to casein-enriched diets, leading to lower the LDL/HDL ratio. Consequently, discrepancies observed between our results and previous reports would be partially due to the nature of dietary proteins which would greatly influence the saponin effects on lipid metabolism and egg yolk cholesterol quantities. The previously reported antioxidant properties of saponins were based on their capacity to increase glutathione concentrations and to limit lipid peroxidations [27]. In this study, a tendency for plasma glutathione concentrations to increase was noticed particularly since the first period, but only statistically significant differences with control group were obtained for the group receiving the lowest dose of Yucca powder. On the 8th week, the total antioxidant capacity was

also weakly enhanced in groups receiving 100 and 150 ppm of deodorase. Antioxidant capacity is an important factor for all physiological standards and for production performance in human and all animals [5, 19]. Moreover, this study is the first report showing the positive effects of dietary supplementation with Deodorase on antioxidant capacity in birds. Nevertheless, the antioxidant effects of Yucca saponins evidenced in our study were relatively weak and could be closely related to the slight diminution of the leukocyte counts, and probably they were not directly responsible for the improvement of egg production. As a conclusion, dietary supplementation by Yucca schidigera powder at low doses (100 ppm and 150 ppm at a lesser extend) has improved egg production in laying hens, increased antioxidant capacities and lowered glycemia and cholesterolemia. Therefore, Yucca schidigera powder may be considered as environmentally friendly supplement for laying hens and, may be other animals. But further investigations are necessary to determine the saponin effects on intestinal motility, lipoprotein and lipid-soluble vitamin concentrations.

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