Effects of supplementing diet with Thyme (Thymuas vulgaris L.) essential oil and/or selenium yeast on production performance and blood variables of broiler chickens.

BACKGROUND: Organic products for animals are becoming more widely accepted by consumers. Using herbal additives may lead to more healthy animal products. In this research, it is hypothesized that thyme essential oil (TEO) and/or selenium yeast (SY) would be helpful to enhance production performance in broilers. OBJECTIVE: In the current study, the effects of adding TEO and/or SY to the diet on broiler performance and blood parameters were evaluated in broiler chickens. METHODS: A total of 480 chicks were distributed in 24 cages with 20 chicks (10 males and 10 females) each and assigned to be fed four iso-caloric and iso-nitrogenous diets including two levels (0 and 250 mg/kg) of TEO and two levels (0 and 0.3 mg/kg) of SY in a 2 × 2 factorial arrangement with six replicates. RESULTS: Adding SY significantly decreased feed intake in finishing period (22-42 d) (p < 0.05). Supplementation with SY and TEO significantly decreased plasma uric acid and triglyceride levels, respectively (p < 0.05). However, neither of the supplements had any influence on the plasma glucose and albumin levels (p > 0.05). The lowest level of plasma cholesterol was detected in the birds fed the TEO-supplemented diet (p < 0.05). Addition of SY significantly increased blood glutathione peroxidase activity (p < 0.05). CONCLUSIONS: Dietary supplemental TEO has a favourable effect on feed intake, weight gain, and body weight values. Besides, SY may decrease blood concentration of uric acid, as well as blood glutathione peroxidase activity. An interaction is detected between TEO and SY on blood cholesterol.

Production performance, egg quality and some blood parameters of heat-stressed laying hens as affected by dietary supplemental Vit B6, Mg and Zn.

OBJECTIVES: The effects of dietary supplements, including magnesium sulfate (Mg), zinc oxide (Zn) and vitamin B6 (Vit B6), on the performance of laying hens reared under normal (NC) and heat-stress (HSC) conditions were investigated. MATERIAL AND METHODS: A total of 288 30-week-old Lohmann LSL-Lite laying hens were randomly divided into 48 cages and assigned to receive one of the eight diets with six replicates and six hens per replicate, based on a 2 × 2 × 2 factorial arrangement of treatments. Dietary supplements, including two levels (0 & 600 mg/kg) of Mg, two levels (0 & 30 mg/kg) of Zn and two levels (0 & 8 mg/kg) of Vit B6, in normal and heat-stress conditions, were tested at 30-40 and 41-45 weeks of age, respectively. RESULTS: In the Vit B6 group, a decrease in feed intake (FI), egg production (EP), albumin, Zn, Fe and Mg, and an increase in triglyceride and insulin in HSC were observed, in addition to a decrease in cholesterol and an increase in egg weight (EW) in NC. Supplemental Mg decreased EP, blood triglycerides and copper in NC, and Zn, Fe and Mg in HSC as well. Feeding Zn, increased egg shape index, total protein and copper in addition to yolk index in NC and Fe in HSC. EWs were higher in hens supplemented with Vit B6+Mg in HSC. Increased insulin and decreased glutathione peroxidase activity were detected with the Vit B6+Zn compared to feeding either Vit B6 or Zn in HSC. CONCLUSIONS: The results indicated Vit B6 could improve EWs and suppress blood cholesterol in NC. Zn improved the egg shape index in NC.

Effects of supplementing hen diet with Lavandula angustifolia and/or Mentha spicata essential oils on production performance, egg quality and blood variables of laying hens.

BACKGROUND: Organic products of animals are getting more accepted by consumers. Using herbal additives may lead to more health animal products. In this research it is hypothesized that Lavandula angustifolia and/or Mentha spicata essential oils would be helpful to enhance production performance in laying hens. OBJECTIVES: This experiment was conducted to evaluate the effects of Lavandula angustifolia and Mentha spicata essential oils on performance, egg traits and blood variables in laying hens. METHODS: 144 Lohmann LSL-Lite laying hens from 42 until 56 weeks of age were used in a completely randomized design in four treatments and six replicates (six birds per replicate). The treatments consisted of: (a) control group (basal diet), (b) basal diet supplemented with 250 mg/kg diet lavender essential oil (LEO), (c) basal diet supplemented with 250 mg/kg diet mint essential oil (MEO), and (d) basal diet supplemented with both LEO and MEO. RESULTS: Using LEO and/or MEO did not affect body weight changes, feed intake, egg weight, egg index, yolk index, Haugh unit, egg shell weight and egg shell thickness. Feeding LEO, individually or in combination with MEO, did not affect FCR compared with the control group (p < .05), however, feeding MEO individually increased feed conversation ratio (FCR) compared to LEO and the control group during 42-56 weeks (p < .05), as well as decreasing egg mass compared to LEO (p < .05). Feeding LEO increased egg production compared to MEO and combination of MEO and LEO (p < .05). CONCLUSIONS: In conclusion, dietary supplemental MEO (250 mg/kg) may increase FCR, and LEO (250 mg/kg) is more effective than MEO (250 mg/kg) for egg production and egg mass purposes; besides MEO (250 mg/kg) negatively affected FCR compared with the control group. In addition, no specific beneficial effect of dietary supplemental MEO and/or LEO on the other measured variables was detected.

Effects of dietary supplemental lysophospholipids and vitamin C on performance, antioxidant enzymes, lipid peroxidation, thyroid hormones and serum metabolites of broiler chickens reared under thermoneutral and high ambient temperature.

The effects of dietary supplemental lysophospholipids (LPLs) and vitamin C (VC) on performance, activity of antioxidant enzymes, and thyroid hormones of broiler chickens reared under thermoneutral and high ambient temperatures were evaluated. A total of 1,680 broiler chicks (Cobb 500) in finishing rearing period (days 21-38 of age) were allotted to two groups: thermoneutral (TN) and heat stress (HS). In the TN group, 480 chicks were subjected to four treatments with four replicates (n = 30) and maintained in usual ambient temperature (24 ± 1°C). In HS group, the remaining 1,200 chicks were subjected to four treatments with 10 replicates (n = 30) and exposed to high ambient temperature (34 ± 1°C for 8 hr daily). In both groups, four iso-caloric and iso-nitrogenous experimental diets based on a 2 × 2 factorial arrangements including supplemental LPLs (0 or 1,000 mg/kg) and VC (0 or 500 mg/kg) were formulated and used. Supplemental LPLs decreased (p < 0.05) body weight gain and increased FCR in the TN and HS groups. In the TN group, increased (p < 0.05) serum glucose was observed in chickens fed with dietary supplemental VC. In the HS group, decreased (p < 0.05) total protein concentration was detected in birds fed with supplemental LPLs. In both TN and HS groups, decreased (p < 0.05) uric acid concentration was detected in chicks fed with the VC-supplemented diets. A significant (p < 0.05) interaction between LPLs and VC on lactate concentration in the TN group was observed. In the HS group, decreased breast malondialdehyde concentration was detected in birds fed with the VC-supplemented diet. In the TN group, increased serum total antioxidant status was detected in birds fed with the LPLs-supplemented diet. In conclusion, LPLs improved oxidative stability and increased the antioxidant capacity of the serum. In addition, vitamin C modified heat stress and reduced lipid peroxidation.

Single and combined effects of peppermint and thyme essential oils on productive performance, egg quality traits, and blood parameters of laying hens reared under cold stress condition (6.8 ± 3 °C).

This study was conducted to evaluate the effects of adding peppermint essential oil (PEO), thyme essential oil (TEO), or their combination to diet on productive performance, egg quality traits, and blood parameters of laying hens reared under cold stress condition (6.8 ± 3 °C). Feed intake (FI), feed conversion ratio (FCR), egg weight (EW), egg production (EP), and egg mass (EM) were evaluated during the 56-day trial period using 120 Lohmann LSL-lite laying hens. Significant interactions between PEO and TEO on FCR, EP, and EM were observed (P < 0.05). The EP and EM increased, whereas FCR decreased (P < 0.05) in the hens fed the diets supplemented by the combined form of PEO and TEO compared to those fed the basal diet. Also, increased EW and FI were observed in the laying hens fed the diet added by PEO compared to the birds fed the basal diet. There were significant interactions between PEO and TEO on the serum level of cholesterol, shell thickness, and Hough unit of egg (P < 0.05), so that serum content of cholesterol decreased, but egg shell thickness and Hough unit increased in the hens fed the diet supplemented by the combined form of PEO and TEO compared to those fed the basal diet. From the results of the present experiment, it can be concluded that diet supplementation by combined form of PEO and TEO could have beneficial effects on performance parameters of hens reared under cold stress condition.

Effects of adding aqueous extract of Tribulus terrestris to diet on productive performance, egg quality characteristics, and blood biochemical parameters of laying hens reared under low ambient temperature (6.8 ± 3 °C).

A study was conducted using 144 laying hens to evaluate the effects of adding aqueous extract of Tribulus terrestris to diets on productive performance, egg quality traits, and some blood parameters of laying hens reared under cold stress condition (6.8 ± 3 °C). The birds were randomly assigned to each of four dietary treatments (C, T1, T2, and T3) with six replicate cages of six birds. Diet inclusion of aqueous extract of T. terrestris at the rate of 10, 20, and 30 ml/Lit offered to groups T1, T2, and T3, respectively, while group C served as the control diet with no addition. Feed intake (FI), feed conversion ratio (FCR), egg weight (EW), egg production (EP), and egg mass (EM) were evaluated during the 42-day trial period. The EP and EM increased, whereas FCR decreased (P < 0.001) in the hens fed the extract-included diet as compared to those fed the basal diet. The serum content of cholesterol decreased and the thickness of egg shell increased in the hens fed the T2 and T3 diet compared to those fed the basal diet. Overall from the results of the present experiment, it can be concluded that diet supplementation with aqueous extract of T. terrestris has beneficial effects on productive performance of laying hens reared under cold stress condition.

Single and combined effects of zinc and cinnamon essential oil in diet on productive performance, egg quality traits, and blood parameters of laying hens reared under cold stress condition.

This study was conducted to evaluate the effects of adding zinc (Zn), cinnamon essential oil (Ci), or their combination in diet on productive performance, egg quality, and blood parameters of laying hens reared under cold stress condition (8.8 ± 3 °C). Feed intake (FI), feed conversion ratio (FCR), egg weight (EW), egg production (EP), and egg mass (EM) were evaluated during the 56-day trial period using 120 Lohmann LSL-Lite laying hens. Significant interactions between Ci and Zn on FCR, EW, EP, or EM were observed (P < 0.05). The EP, EM, and EW increased, whereas FCR decreased (P < 0.05) in the hens fed the diets including Ci and Zn (as single or combined form) compared to those fed the basal diet. There were significant interactions between Ci and Zn on the serum level of glucose and triglycerides as well as plasma concentration of zinc (P < 0.05), so that serum content of glucose and triglyceride decreased and the plasma content of zinc increased in the hens fed the diets including Ci and Zn (together) compared to those fed the basal diet. From the results of the present experiment, it can be concluded that diet supplementation by the combined form of Ci and Zn could have beneficial effects on performance and blood parameters of hens reared under cold stress condition.

Response of laying hens to feeding low-protein amino acid-supplemented diets under high ambient temperature: performance, egg quality, leukocyte profile, blood lipids, and excreta pH.

An experiment was conducted to determine whether, by using a low-protein amino acid-supplemented diet, the health status, stress response, and excreta quality could be improved without affecting the productive performance of heat-stressed laying hens. The requirements for egg production, egg mass, and feed conversion ratio were also estimated using second-order equations and broken-line regression. A total of 150 Lohmann Selected Leghorn (LSL-Lite) hens were divided randomly into five groups of 30 with five replicates of six hens. The hens were raised for an 8-week period (52 to 60 weeks) in wire cages situated in high ambient temperature in an open-sided housing system. The five experimental diets (ME; 2,720 kcal/kg) varied according to five crude protein (CP) levels: normal-CP diet (control, 16.5 % CP) and low-CP diets containing 15.0, 13.5, 12.0, or 10.5 % CP. All experimental diets were supplemented with crystalline amino acids at the levels sufficient to meet their requirements. The results showed that under high temperature conditions, all productive performance and egg quality parameters in the birds fed with 15.0, 13.5, and 12.0 % CP diets were similar to those of birds fed with control diet (16.5 % CP), whereas feeding 10.5 % CP diet significantly decreased egg production and egg mass. Estimations of requirements were of 13.93 and 12.77 % CP for egg production, 14.62 and 13.22 % CP for egg mass, and 12.93 and 12.26 % CP for feed conversion ratio using quadratic and broken-line models, respectively. Egg yolk color index, blood triglyceride level, and excreta acidity were also significantly higher in birds fed with 12.0 and 10.5 % CP diets compared with those of control birds. The heterophil to lymphocyte ratio, as a stress indicator, was significantly decreased by 15.0, 13.5, and 12 % CP diets. On the basis of our findings, reducing dietary CP from 16.5 to 12.0 % and supplementing the diets with the essential amino acids showed merit for improving the stress response and excreta quality while maintaining acceptable production performance from laying hens under high ambient temperature conditions.

Performance, egg quality traits, and serum metabolite concentrations of laying hens affected by dietary supplemental chromium picolinate and vitamin C under a heat-stress condition.

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).

Effects of dietary chromium picolinate and peppermint essential oil on growth performance and blood biochemical parameters of broiler chicks reared under heat stress conditions.

A study was conducted using 240 female day-old broiler chicks to evaluate the effects of dietary chromium picolinate (CrPic), peppermint essential oil (P.mint), or their combination on growth performance and blood biochemical parameters of female broiler chicks raised under heat stress conditions (HS, 23.9 to 38 °C cycling). Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were obtained from 1 to 42 days of age. Furthermore, at the end of the experiment (day 42), birds were bled to determine some blood biochemical parameters and weighed for final body weight (BW). ADFI, ADG, and BW were not influenced significantly by dietary CrPic and P.mint (P>0.05). A significant interaction between dietary CrPic and P.mint on FCR (P=0.012) was detected. FCR significantly decreased in chicks fed the diet including both CrPic and P.mint compared with the CrPic group. Significant interaction between dietary P.mint and CrPic on serum concentrations of triglycerides, glucose, and albumin were observed (P<0.05), but the other measured blood biochemical parameters were not statistically affected by dietary treatments (P>0.05). The serum concentrations of glucose, triglycerides were decreased (P<0.05) in broilers fed the diet including both CrPic and P.mint. Plasma chromium (Cr) content increased significantly (P<0.05) in birds fed the CrPic-included diet compared with the control group (P<0.05). From the results of the present experiment it can be concluded that dietary supplementation with combined P.mint and CrPic could have beneficial effects on some blood biochemical parameters of female chicks reared under heat stress conditions.

Periodic usage of low-protein methionine-fortified diets in broiler chickens under high ambient temperature conditions: effects on performance, slaughter traits, leukocyte profiles and antibody response.

This study was performed to evaluate the effects of adding methionine supplements to low-protein diets and subsequent re-feeding with a normal diet on the productive performance, slaughter parameters, leukocyte profiles and antibody response in broiler chickens reared under heat stress conditions.During the whole experimental period (6-49 days), the birds were raised in battery cages located in high ambient temperature in an open-sided housing system. A total of 360 6-day-old male chickens were divided into six treatments in six replicates with ten chicks each. Six isoenergetic diets, with similar total sulfur amino acids levels, were formulated to provide 100 and 100 (control), 85 and 100 (85S), 70 and 100 (70S), 85 and 85 (85SG), 70 and 85 (70S85G), and 70 and 70% (70SG) of National Research Council recommended levels for crude protein during the starter (6-21 day) and grower (22-42 day) periods, respectively. Subsequently, all groups received a diet containing the same nutrients during the finisher period (43-49 day). The results showed that, under heat stress conditions, average daily gain and feed conversion ratio and performance index from day 6 to 49, breast and thigh yields and antibody titer against Newcastle disease in the birds fed diets 85S, 70S and 85SG were similar to those of birds fed control diet, whereas feeding diets 70S85G and 70SG significantly decreased the values of above-mentioned parameters. Additionally, diets 85S, 70S and 85SG significantly decreased mortality rate and heterophil:lymphocyte ratio compared with the control diet. In conclusion, the results indicate that supplementation of methionine to diets 85S, 70S and 85SG, and then re-feeding with a conventional diet is an effective tool to maintain productive performance and to improve health indices and heat resistance in broilers under high ambient temperature conditions.