Effects of some Growth Promoters on Blood Hematology and Serum Composition of Broiler Chickens

MATERIALS AND METHODS

Experimental design: In this study, 450 broiler chickens of the commercial “Hubbard Flex” strain were used in a randomized completely design with 5 groups; 4 treatment groups and a control group, 3 replicates in each group and 30 birds replicates. Birds were raised on floor pens (300x300x100 cm) for 42 days and had free access to feed and water throughout the entire experimental period. The lighting program consisted of a period of 23 h light and 1 h of darkness.

Feeding: The chicks were fed as standard starter (1-14 days), grower (15-35 days) and finisher (36-42 days) diets according to feed mixture followed in the Department of Animal Production at the University of Damascus (Table 1). Groups were randomly assigned to following treatment groups:

Table 2 shows the analysis of nutrient material in testing portion.

Hematological parameters: At 42 days of age, two birds were chosen randomly from each replicate for bleeding. The 3 mL of blood was collected from wing vein from two birds of each replicate into anticoagulant EDTA treated tubes for determination of total Red Blood Cell (RBC), total White Blood Cell (WBC), hemoglobin (HB) and hematocrit (HCT). The following hematological parameters were assessed by using Automatic Fully Digital Hematology Analyzer, BC- 3000 Plus, Shenzhen Mindray, Bio-Medical Electronics Co., LTD.

Table 1:	Composition of basal diet in different periods of the experiment

Table 2:	Nutrient content of the basal diets

Serum biochemical parameters: On 42 day of experimental period, 3 mL of blood was collected from wing vein from two birds of each replicate (from six birds of each treatment). Serum was isolated by centrifugation at 2,000xrbm for 10 min. The serum concentrations of glucose, total triglyceride, cholesterol, High Density Lipoprotein (HDL), cholesterol and Low Density Lipoprotein (LDL) ratio in serum samples were analyzed by an automatic biochemical analyzer (Clima, Ral. Co, Espain).

Statistical analysis: Data was subjected to a one-way analysis of variance (ANOVA) and the comparison of means was carried out through Least Significant Differences (LSD) test. All statistical analyses were done using SPSS program (SPSS, 2002).

RESULTS AND DISCUSSION

Table 3 shows the effect of different diets on hematological blood parameters, no significant differences were observed in the RBC number of birds of different treatment except for a non significant (p>0.05) increase in the red blood cells number in antibiotic and probiotic treatments. Also, results showed that a significant increase in the number of White Blood Cells (WBC) (p<0.05) was observed in all treatments except for antibiotic treatment which showed a significant decrease compared to organic acid and probiotic treatment, respectively. It seems that the microbial interactions and effects on local immune stimulation results increase of white blood cells and immunity. These results are accordance with findings of Zareshahneh et al. (2007) and EFSA (2010) but are not accordance with findings of Shareef and Al-Dabbagh (2009).

Table 3:	Values of blood hematological parameters of experimental groups
Means in each row with different superscripts are significantly different (p<0.05)

Table 4:	Values of serum biochemical parameters of experimental groups
Means in each row with different superscripts are significantly different (p<0.05)

No significant differences were found in the blood hemoglobin levels in all treatments (p>0.05) inspite of an increase in the antibiotic treatment. This result did not resemble the results of the Al-Mayah and Al-Ahmed (2005). It may be due to the type of antibiotic and its mechanism of action or place of impact.

Significant increase was also noted in haematocrit values (HCT) in probiotic treatment compared with the another treatments and this is in agreement with the study done by Cetin et al. (2005), who observed that the probiotic supplementation caused statistically significant increase in the erythrocyte count, haemoglobin concentration and haematocrit values of Turkeys. In contrast, the findings disagree with Djouvinov et al. (2005), who found that the probiotic supplementation did not affect the blood constituents comprising haemoglobin concentrations. The differences may be attributed to type and number of species of bacteria present in probiotics.

Levels of serum glucose, triglyceride, total cholesterol, HDL and LDL are shown in Table 4. There was no significant effect of treatments on glucose levels, the non significant decrease in blood glucose level of organic acids treatment is in agreement with Adil et al. (2010). A significant decrease was observed in triglycerides and cholesterol values in the probiotic, organic acid and prebiotic treatments, respectively. A decrease of serum cholesterol via adding acidifier to diet was also reported by Abdel-Fattah et al. (2008). The role of organic acids in decreasing blood fat may be explained by their effect on decreasing intracellular microbes by preventing microbial enzymes activity and forcing cellular bacteria to use energy in order to release protons which cause forming of mass intracellular anions. In agreement to present results, Taherpour et al. (2009) and Ashayerzadeh et al. (2010) noted the decline of plasma cholesterol level by adding probiotic and prebiotic to broiler diets the significant reduction in serum cholesterol level could be attributed to reduced absorption and/or synthesis of cholesterol in the gastro-intestinal tract by probiotic or prebiotic supplementation (Mohan et al., 1995, 1996) also Patterson and Burkholder (2003) noted that decreasing in triglycerides and attributed the reason that probiotic and prebiotic secrete inulin which have an inhibitory effect on the process of building triglycerides.

Addition of antibiotic showed a higher blood triglyceride and cholesterol which is in agreement with Li et al. (2007) and Mansoub (2011), who attributed it to the low effect of these antibiotics on the absorption of fat in the GI. The serum HDL concentration was significantly increased in probiotic and prebiotic treatments compared to control (p<0.05). This is in agreement with Kalavathy et al. (2003), Jouybari et al. (2009) and Hashemzadeh et al. (2013). Results also showed significant decrease (p<0.05) in the serum LDL concentration in probiotic and prebiotic treatment compared to other groups which agrees with Panda et al. (2006) who attributed this decrease to the relationship between LDL and triglycerides.