A 3×2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromium ... more A 3×2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromium picolinate) and two levels (0 and 250 mg/kg) of vitamin C was employed to evaluate the effects of these dietary supplements on performance , egg quality traits, and serum biochemical parameters of heat-stressed laying hens (Lohmann LSL-Lite) from 66 to 74 weeks of age. Feed intake increased when birds were given either 400 μg/kg chromium or 250 mg/kg vitamin C (P <0.05), but the birds that received both chromium and vitamin C consumed feed similar to those that received only chromium. Dietary treatments had no effect on egg production , egg mass, egg volume, feed conversion ratio, and body mass (P >0.05). The birds that fed on diet with chromium or vitamin C produced eggs with higher shell mass and thickness compared to the control. Both eggshell mass and thickness decreased when vitamin C and chromium were supplemented simultaneously, and birds given the diet supplemented with 400 μg/kg chromium and 250 mg/kg vitamin C had eggshell mass and thickness similar to those of the control group. The serum concentration of chromium increased due to increasing level of dietary chromium (P <0.05). The birds that received diet with chromium and vitamin C had higher serum concentrations of chromium compared to those that received only chromium (P <0.05). Similarly, the hens that received chromium and vitamin C had higher serum concentrations of calcium and phosphorus compared to the hens fed with other treatments (P <0.05). The birds given with supplemental chromium exhibited lower serum glucose, total cholesterol, and triglycerides concentrations but higher serum albumin and total protein concentrations compared to the other groups (P <0.05).
ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium o... more ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium on growth performance and oxidative stability of skeletal muscle of broilers under heat stress (HS). Birds raised in either a thermoneutral (23.9°C constant) or HS (23.9 to 37°C cycling) environment were fed on corn-soybean meal basal diets with different concentrations of vitamin E (0, 125, or 250 mg/kg) and selenium (0, 0.5, or 1.0 mg/kg) either alone or in combinations from 1 to 49 days of age. Pectoralis superficialis muscle was used for measurement of oxidative stability of skeletal muscle. Body weight, feed intake and feed conversion ratio were not significantly influenced by dietary vitamin E and selenium (P&gt;0.05), whereas heat stress significantly reduced body weight, feed intake, and feed conversion ratio (P&lt;0.05). Glutathione peroxidase (GPx) activity and malondialdehyde (MDA) levels in skeletal muscle were enhanced by heat treatment, while dietary inclusions of vitamin E and selenium resulted in a greater GPx activity, but lower MDA concentrations in skeletal muscle (P&lt;0.05). These results indicated that HS severely reduced growth performance and oxidative stability of skeletal muscle of broilers, whereas the oxidative stability of broilers skeletal muscle could be improved by dietary vitamin E and selenium supplementation under HS.
This study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E ... more This study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125, and 250 mg/kg), selenium (0, 0.5, and 1 mg/kg), or their different combinations on performance, meat yield, and selenium content and lipid oxidation of breast meat of broilers raised under either a thermoneutral (TN, 24 °C constant) or heat stress (HS, 24 to 37 °C cycling) condition. There was a reduction (P &amp;amp;amp;amp;amp;amp;lt; 0.05) in body weight and feed intake and an increase (P &amp;amp;amp;amp;amp;amp;lt; 0.05) in feed conversion ratio when broilers exposed to HS. In the overall period of the study (1 to 49 days), growth performance of TN broilers was not affected (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by vitamin E and selenium supplementation. However, under HS condition, broilers receiving 250 mg/kg vitamin E and 0.5 mg/kg selenium consumed more (P &amp;amp;amp;amp;amp;amp;lt; 0.05) feed than that of broilers receiving 250 mg/kg vitamin E alone, but similar (P &amp;amp;amp;amp;amp;amp;gt; 0.05) to that of broilers receiving 250 mg/kg vitamin E and 1 mg/kg selenium. The malondialdehyde (MDA) content of the breast meat was increased (P &amp;amp;amp;amp;amp;amp;lt; 0.05), but its selenium content was decreased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by exposure to HS. The breast meat selenium content was increased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by selenium supplementation. The breast meat selenium content was decreased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by supplementation of 250 mg/kg vitamin E to diet of TN birds. However, the breast meat selenium content was increased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by supplementation of vitamin E under HS condition. The breast meat MDA content was not affected (P &amp;amp;amp;amp;amp;amp;gt; 0.05) by dietary treatments under TN condition. However, the breast meat MDA content was decreased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by both vitamin E and selenium supplementation under HS condition, and the lowest MDA content was observed in the breast meat of broilers receiving combination of 125 mg/kg vitamin E and 1 mg/kg selenium. The results showed that supplementation of selenium and vitamin E was capable of increasing the selenium content of the breast meat and could improve the lipid oxidation of the breast meat when broilers reared under HS condition.
ABSTRACT A total of 1,400 one-day-old male Ross 308 broiler chicks were used to examine the effec... more ABSTRACT A total of 1,400 one-day-old male Ross 308 broiler chicks were used to examine the effects of inclusion of alternative carbohydrate and protein sources in prestarter diets and the form of diet on subsequent performance, physiological development, and carcass characteristics of broilers. The experimental diets were offered from 1 to 7 days of age and were as follows: CON: control corn-soybean-fish meal diet; CD: corn-soybean meal-casein-dextrose diet; CS: corn-soybean meal-casein-corn starch diet; GD: corn-soybean meal-corn gluten-dextrose diet; and GS: corn-soybean meal-corn gluten-corn starch diet. Each diet was provided in either solid or semi-moist (30% moisture) form, resulting in 10 dietary treatments in a 5 × 2 factorial arrangement. During the first week, a significant (P &lt; 0.05) decrease in feed intake and weight gain was observed in the chicks receiving the CD or the CS diet compared with the chicks receiving the CON diet. Chicks receiving the CON diet also exhibited lower (P &lt; 0.05) feed conversion ratio than those receiving the CD or the CS diet. The adverse effect of feeding the CD and CS diets on live weight of the birds was still evident at 21 and 42 days of age (P &lt; 0.05). Chicks on the semi-moist diets consumed less (P &lt; 0.05) feed than those on the solid diets during the first week. Nevertheless, chicks fed the semi-moist diets had higher (P &lt; 0.05) weight gain and exhibited lower (P &lt; 0.05) feed conversion ratio than those fed the solid diets. During the entire period, the highest weight gain and feed intake were observed in chicks receiving the CON prestarter diet in semi-moist form. During the first week, chicks receiving the CD or the CS diet exhibited the lowest (P &lt; 0.05) small intestine weight and length. Conversely, at day 21 of age, these chicks had higher (P &lt; 0.05) small intestine weight than the other chicks. According to these results, it can be concluded that using a corn-soybean-fish meal-based prestarter diet in semi-moist form improves chick development and positively affects growth performance.
A study was conducted to evaluate the effects of dietary inclusion of ground pits of date palm (D... more A study was conducted to evaluate the effects of dietary inclusion of ground pits of date palm (DP) (Phoenix dactylifera) supplementing with a commercial probiotic mixture (Yeasture®) on the performance, egg quality characteristics, blood parameters, and excreta pH of laying hens. A total of 144 Lohmann LSL-Lite laying hens were randomly divided in 24 cages. Based on a 3×2 factorial arrangement of treatments in a completely randomized design with four replicates, 6 iso-caloric and iso-nitrogenous experimental diets (ME=2720 kcal/kg and CP=150 g/kg) including: I-corn-soybean meal-based control-1 diet, II-corn-soybean meal-oil-based control-2 diet, and III-corn-soybean meal-based diet included 210 g/kg DP with or without probiotic (0.0 and 0.05 g/kg) were formulated. Dietary treatment had no significant effect on feed intake, feed conversion ratio and body weight as well as egg production and egg mass (P>.05). Probiotic supplementation did not significantly affect laying performanc...
This experiment was carried out to investigate the effects of different levels of organic and ino... more This experiment was carried out to investigate the effects of different levels of organic and inorganic chromium on the performance, immune function and some serum mineral concentrations of broilers under heat stress condition (23.9-37°C cycling). A total of 150 one-day-old broiler chicks according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Chicks were fed on corn-soybean meal basal diets with added different concentrations of chromium (0, 600 and 1,200 μg kg(-1) chromium chloride or 600 and 1,200 μg/kg chromium L-methionine) from 1 to 49 days of age. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed by the cutaneous basophil hypersensitivity (CBH) test to phytohemagglutinin (PHA)-P at day 32 and PHA-M at ...
A 3 × 2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromiu... more A 3 × 2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromium picolinate) and two levels (0 and 250 mg/kg) of vitamin C was employed to evaluate the effects of these dietary supplements on performance, egg quality traits, and serum biochemical parameters of heat-stressed laying hens (Lohmann LSL-Lite) from 66 to 74 weeks of age. Feed intake increased when birds were given either 400 μg/kg chromium or 250 mg/kg vitamin C (P &lt; 0.05), but the birds that received both chromium and vitamin C consumed feed similar to those that received only chromium. Dietary treatments had no effect on egg production, egg mass, egg volume, feed conversion ratio, and body mass (P &gt; 0.05). The birds that fed on diet with chromium or vitamin C produced eggs with higher shell mass and thickness compared to the control. Both eggshell mass and thickness decreased when vitamin C and chromium were supplemented simultaneously, and birds given the diet supplemented with 400 μg/kg chromium and 250 mg/kg vitamin C had eggshell mass and thickness similar to those of the control group. The serum concentration of chromium increased due to increasing level of dietary chromium (P &lt; 0.05). The birds that received diet with chromium and vitamin C had higher serum concentrations of chromium compared to those that received only chromium (P &lt; 0.05). Similarly, the hens that received chromium and vitamin C had higher serum concentrations of calcium and phosphorus compared to the hens fed with other treatments (P &lt; 0.05). The birds given with supplemental chromium exhibited lower serum glucose, total cholesterol, and triglycerides concentrations but higher serum albumin and total protein concentrations compared to the other groups (P &lt; 0.05).
ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium o... more ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium on growth performance and oxidative stability of skeletal muscle of broilers under heat stress (HS). Birds raised in either a thermoneutral (23.9°C constant) or HS (23.9 to 37°C cycling) environment were fed on corn-soybean meal basal diets with different concentrations of vitamin E (0, 125, or 250 mg/kg) and selenium (0, 0.5, or 1.0 mg/kg) either alone or in combinations from 1 to 49 days of age. Pectoralis superficialis muscle was used for measurement of oxidative stability of skeletal muscle. Body weight, feed intake and feed conversion ratio were not significantly influenced by dietary vitamin E and selenium (P&gt;0.05), whereas heat stress significantly reduced body weight, feed intake, and feed conversion ratio (P&lt;0.05). Glutathione peroxidase (GPx) activity and malondialdehyde (MDA) levels in skeletal muscle were enhanced by heat treatment, while dietary inclusions of vitamin E and selenium resulted in a greater GPx activity, but lower MDA concentrations in skeletal muscle (P&lt;0.05). These results indicated that HS severely reduced growth performance and oxidative stability of skeletal muscle of broilers, whereas the oxidative stability of broilers skeletal muscle could be improved by dietary vitamin E and selenium supplementation under HS.
This study evaluated the effects of supplemental dietary chromium (Cr) on the performance, carcas... more This study evaluated the effects of supplemental dietary chromium (Cr) on the performance, carcass traits, and some serum parameters of broilers under a heat stress (23.9 to 37 °C cycling) condition. A total of 150 1-day-old broiler chicks (Cobb 500) according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Treatments were supplemented with 0 (control), 600, and 1,200 ìg kg.1 Cr in the form of Cr chloride (CrCl3) and Cr L-methionine from 1 to 49 days of age. Blood samples were collected from two birds in each replicate to determine serum parameters at 35 and 49 days of age. The body mass, feed intake, and conversion ratio were not influenced by dietary Cr (P>0.05). Dietary supplementation of Cr from either CrCl3 or Cr L-methionine caused increased serum concentrations of Cr (P<0.05), but had no effect on serum insulin and glucose concentrations at both sampling times (P>0.05). Serum triglycerides, very low-density lipoprotein cholesterol, lowdensity lipoprotein cholesterol, and high-density lipoprotein cholesterol were also not significantly affected (P>0.05) by dietary treatments, whereas total cholesterol concentration decreased in chicks fed Cr L-methionine compared to the control (P<0.05).
A 3×2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromium ... more A 3×2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromium picolinate) and two levels (0 and 250 mg/kg) of vitamin C was employed to evaluate the effects of these dietary supplements on performance , egg quality traits, and serum biochemical parameters of heat-stressed laying hens (Lohmann LSL-Lite) from 66 to 74 weeks of age. Feed intake increased when birds were given either 400 μg/kg chromium or 250 mg/kg vitamin C (P <0.05), but the birds that received both chromium and vitamin C consumed feed similar to those that received only chromium. Dietary treatments had no effect on egg production , egg mass, egg volume, feed conversion ratio, and body mass (P >0.05). The birds that fed on diet with chromium or vitamin C produced eggs with higher shell mass and thickness compared to the control. Both eggshell mass and thickness decreased when vitamin C and chromium were supplemented simultaneously, and birds given the diet supplemented with 400 μg/kg chromium and 250 mg/kg vitamin C had eggshell mass and thickness similar to those of the control group. The serum concentration of chromium increased due to increasing level of dietary chromium (P <0.05). The birds that received diet with chromium and vitamin C had higher serum concentrations of chromium compared to those that received only chromium (P <0.05). Similarly, the hens that received chromium and vitamin C had higher serum concentrations of calcium and phosphorus compared to the hens fed with other treatments (P <0.05). The birds given with supplemental chromium exhibited lower serum glucose, total cholesterol, and triglycerides concentrations but higher serum albumin and total protein concentrations compared to the other groups (P <0.05).
ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium o... more ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium on growth performance and oxidative stability of skeletal muscle of broilers under heat stress (HS). Birds raised in either a thermoneutral (23.9°C constant) or HS (23.9 to 37°C cycling) environment were fed on corn-soybean meal basal diets with different concentrations of vitamin E (0, 125, or 250 mg/kg) and selenium (0, 0.5, or 1.0 mg/kg) either alone or in combinations from 1 to 49 days of age. Pectoralis superficialis muscle was used for measurement of oxidative stability of skeletal muscle. Body weight, feed intake and feed conversion ratio were not significantly influenced by dietary vitamin E and selenium (P&gt;0.05), whereas heat stress significantly reduced body weight, feed intake, and feed conversion ratio (P&lt;0.05). Glutathione peroxidase (GPx) activity and malondialdehyde (MDA) levels in skeletal muscle were enhanced by heat treatment, while dietary inclusions of vitamin E and selenium resulted in a greater GPx activity, but lower MDA concentrations in skeletal muscle (P&lt;0.05). These results indicated that HS severely reduced growth performance and oxidative stability of skeletal muscle of broilers, whereas the oxidative stability of broilers skeletal muscle could be improved by dietary vitamin E and selenium supplementation under HS.
This study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E ... more This study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125, and 250 mg/kg), selenium (0, 0.5, and 1 mg/kg), or their different combinations on performance, meat yield, and selenium content and lipid oxidation of breast meat of broilers raised under either a thermoneutral (TN, 24 °C constant) or heat stress (HS, 24 to 37 °C cycling) condition. There was a reduction (P &amp;amp;amp;amp;amp;amp;lt; 0.05) in body weight and feed intake and an increase (P &amp;amp;amp;amp;amp;amp;lt; 0.05) in feed conversion ratio when broilers exposed to HS. In the overall period of the study (1 to 49 days), growth performance of TN broilers was not affected (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by vitamin E and selenium supplementation. However, under HS condition, broilers receiving 250 mg/kg vitamin E and 0.5 mg/kg selenium consumed more (P &amp;amp;amp;amp;amp;amp;lt; 0.05) feed than that of broilers receiving 250 mg/kg vitamin E alone, but similar (P &amp;amp;amp;amp;amp;amp;gt; 0.05) to that of broilers receiving 250 mg/kg vitamin E and 1 mg/kg selenium. The malondialdehyde (MDA) content of the breast meat was increased (P &amp;amp;amp;amp;amp;amp;lt; 0.05), but its selenium content was decreased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by exposure to HS. The breast meat selenium content was increased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by selenium supplementation. The breast meat selenium content was decreased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by supplementation of 250 mg/kg vitamin E to diet of TN birds. However, the breast meat selenium content was increased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by supplementation of vitamin E under HS condition. The breast meat MDA content was not affected (P &amp;amp;amp;amp;amp;amp;gt; 0.05) by dietary treatments under TN condition. However, the breast meat MDA content was decreased (P &amp;amp;amp;amp;amp;amp;lt; 0.05) by both vitamin E and selenium supplementation under HS condition, and the lowest MDA content was observed in the breast meat of broilers receiving combination of 125 mg/kg vitamin E and 1 mg/kg selenium. The results showed that supplementation of selenium and vitamin E was capable of increasing the selenium content of the breast meat and could improve the lipid oxidation of the breast meat when broilers reared under HS condition.
ABSTRACT A total of 1,400 one-day-old male Ross 308 broiler chicks were used to examine the effec... more ABSTRACT A total of 1,400 one-day-old male Ross 308 broiler chicks were used to examine the effects of inclusion of alternative carbohydrate and protein sources in prestarter diets and the form of diet on subsequent performance, physiological development, and carcass characteristics of broilers. The experimental diets were offered from 1 to 7 days of age and were as follows: CON: control corn-soybean-fish meal diet; CD: corn-soybean meal-casein-dextrose diet; CS: corn-soybean meal-casein-corn starch diet; GD: corn-soybean meal-corn gluten-dextrose diet; and GS: corn-soybean meal-corn gluten-corn starch diet. Each diet was provided in either solid or semi-moist (30% moisture) form, resulting in 10 dietary treatments in a 5 × 2 factorial arrangement. During the first week, a significant (P &lt; 0.05) decrease in feed intake and weight gain was observed in the chicks receiving the CD or the CS diet compared with the chicks receiving the CON diet. Chicks receiving the CON diet also exhibited lower (P &lt; 0.05) feed conversion ratio than those receiving the CD or the CS diet. The adverse effect of feeding the CD and CS diets on live weight of the birds was still evident at 21 and 42 days of age (P &lt; 0.05). Chicks on the semi-moist diets consumed less (P &lt; 0.05) feed than those on the solid diets during the first week. Nevertheless, chicks fed the semi-moist diets had higher (P &lt; 0.05) weight gain and exhibited lower (P &lt; 0.05) feed conversion ratio than those fed the solid diets. During the entire period, the highest weight gain and feed intake were observed in chicks receiving the CON prestarter diet in semi-moist form. During the first week, chicks receiving the CD or the CS diet exhibited the lowest (P &lt; 0.05) small intestine weight and length. Conversely, at day 21 of age, these chicks had higher (P &lt; 0.05) small intestine weight than the other chicks. According to these results, it can be concluded that using a corn-soybean-fish meal-based prestarter diet in semi-moist form improves chick development and positively affects growth performance.
A study was conducted to evaluate the effects of dietary inclusion of ground pits of date palm (D... more A study was conducted to evaluate the effects of dietary inclusion of ground pits of date palm (DP) (Phoenix dactylifera) supplementing with a commercial probiotic mixture (Yeasture®) on the performance, egg quality characteristics, blood parameters, and excreta pH of laying hens. A total of 144 Lohmann LSL-Lite laying hens were randomly divided in 24 cages. Based on a 3×2 factorial arrangement of treatments in a completely randomized design with four replicates, 6 iso-caloric and iso-nitrogenous experimental diets (ME=2720 kcal/kg and CP=150 g/kg) including: I-corn-soybean meal-based control-1 diet, II-corn-soybean meal-oil-based control-2 diet, and III-corn-soybean meal-based diet included 210 g/kg DP with or without probiotic (0.0 and 0.05 g/kg) were formulated. Dietary treatment had no significant effect on feed intake, feed conversion ratio and body weight as well as egg production and egg mass (P>.05). Probiotic supplementation did not significantly affect laying performanc...
This experiment was carried out to investigate the effects of different levels of organic and ino... more This experiment was carried out to investigate the effects of different levels of organic and inorganic chromium on the performance, immune function and some serum mineral concentrations of broilers under heat stress condition (23.9-37°C cycling). A total of 150 one-day-old broiler chicks according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Chicks were fed on corn-soybean meal basal diets with added different concentrations of chromium (0, 600 and 1,200 μg kg(-1) chromium chloride or 600 and 1,200 μg/kg chromium L-methionine) from 1 to 49 days of age. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed by the cutaneous basophil hypersensitivity (CBH) test to phytohemagglutinin (PHA)-P at day 32 and PHA-M at ...
A 3 × 2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromiu... more A 3 × 2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromium picolinate) and two levels (0 and 250 mg/kg) of vitamin C was employed to evaluate the effects of these dietary supplements on performance, egg quality traits, and serum biochemical parameters of heat-stressed laying hens (Lohmann LSL-Lite) from 66 to 74 weeks of age. Feed intake increased when birds were given either 400 μg/kg chromium or 250 mg/kg vitamin C (P &lt; 0.05), but the birds that received both chromium and vitamin C consumed feed similar to those that received only chromium. Dietary treatments had no effect on egg production, egg mass, egg volume, feed conversion ratio, and body mass (P &gt; 0.05). The birds that fed on diet with chromium or vitamin C produced eggs with higher shell mass and thickness compared to the control. Both eggshell mass and thickness decreased when vitamin C and chromium were supplemented simultaneously, and birds given the diet supplemented with 400 μg/kg chromium and 250 mg/kg vitamin C had eggshell mass and thickness similar to those of the control group. The serum concentration of chromium increased due to increasing level of dietary chromium (P &lt; 0.05). The birds that received diet with chromium and vitamin C had higher serum concentrations of chromium compared to those that received only chromium (P &lt; 0.05). Similarly, the hens that received chromium and vitamin C had higher serum concentrations of calcium and phosphorus compared to the hens fed with other treatments (P &lt; 0.05). The birds given with supplemental chromium exhibited lower serum glucose, total cholesterol, and triglycerides concentrations but higher serum albumin and total protein concentrations compared to the other groups (P &lt; 0.05).
ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium o... more ABSTRACT This experiment was conducted to evaluate the effect of dietary vitamin E and selenium on growth performance and oxidative stability of skeletal muscle of broilers under heat stress (HS). Birds raised in either a thermoneutral (23.9°C constant) or HS (23.9 to 37°C cycling) environment were fed on corn-soybean meal basal diets with different concentrations of vitamin E (0, 125, or 250 mg/kg) and selenium (0, 0.5, or 1.0 mg/kg) either alone or in combinations from 1 to 49 days of age. Pectoralis superficialis muscle was used for measurement of oxidative stability of skeletal muscle. Body weight, feed intake and feed conversion ratio were not significantly influenced by dietary vitamin E and selenium (P&gt;0.05), whereas heat stress significantly reduced body weight, feed intake, and feed conversion ratio (P&lt;0.05). Glutathione peroxidase (GPx) activity and malondialdehyde (MDA) levels in skeletal muscle were enhanced by heat treatment, while dietary inclusions of vitamin E and selenium resulted in a greater GPx activity, but lower MDA concentrations in skeletal muscle (P&lt;0.05). These results indicated that HS severely reduced growth performance and oxidative stability of skeletal muscle of broilers, whereas the oxidative stability of broilers skeletal muscle could be improved by dietary vitamin E and selenium supplementation under HS.
This study evaluated the effects of supplemental dietary chromium (Cr) on the performance, carcas... more This study evaluated the effects of supplemental dietary chromium (Cr) on the performance, carcass traits, and some serum parameters of broilers under a heat stress (23.9 to 37 °C cycling) condition. A total of 150 1-day-old broiler chicks (Cobb 500) according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Treatments were supplemented with 0 (control), 600, and 1,200 ìg kg.1 Cr in the form of Cr chloride (CrCl3) and Cr L-methionine from 1 to 49 days of age. Blood samples were collected from two birds in each replicate to determine serum parameters at 35 and 49 days of age. The body mass, feed intake, and conversion ratio were not influenced by dietary Cr (P>0.05). Dietary supplementation of Cr from either CrCl3 or Cr L-methionine caused increased serum concentrations of Cr (P<0.05), but had no effect on serum insulin and glucose concentrations at both sampling times (P>0.05). Serum triglycerides, very low-density lipoprotein cholesterol, lowdensity lipoprotein cholesterol, and high-density lipoprotein cholesterol were also not significantly affected (P>0.05) by dietary treatments, whereas total cholesterol concentration decreased in chicks fed Cr L-methionine compared to the control (P<0.05).
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