Effect of Chlorella supplementation on growth performance, immune characteristics, and gut microbiota of broiler chickens

Published on: 3/19/2019
Author/s :
Summary

A study was conducted to investigate the effect of dietary supplementation of Chlorella (Chlorella vulgaris) to replace antibiotic in the diets of broiler chickens. A total of 600 1-d-old straight run broiler chicks was randomly assigned into five treatments with four replicate pens per treatment (30 birds/replicate pen) for 5-week. A corn-soybean meal basal diet (Control) was formulated, and 0.1% virginiamycin as antibiotic growth promoters (AGP), 1.0% dried Chlorella powder (DCP), 1.0% Chlorella growth factor (CGF), and 1.0% fresh liquid Chlorella (FLC) were added to the basal diet to form five dietary treatments. No significant differences were found among the treatments for feed intake and feed conversion of broiler chickens during the whole experimental period, but the BW gain was significantly higher (P < 0.05) in AGP and Chlorella supplemented groups compared to the control group. The number of white blood cells was significantly higher (P < 0.05) in broilers fed FLC compared to DCP, and the number of lymphocytes was also significantly higher (P < 0.05) in FLC compared to AGP and DCP; however, supplemental AGP and Chlorella had no effect on other blood leucocytes of broiler chickens. Dietary supplementation of Chlorella significantly (P < 0.05) increased the plasma IgA concentration of chickens compared to AGP and control. In addition, plasma IgM concentration was higher in DCP and FLC than the control, and plasma IgG concentration was also higher in FLC compared to other treatments. Supplemental AGP and various forms of Chlorella did not affect the E. Coli and Salmonella concentration in the intestinal microflora of broiler chickens, but the population of Lactobacillus was significantly increased (P < 0.05) when birds were fed FLC. It is concluded that dietary supplementation of FLC improves BW gain, immune characteristics, and the production of Lactobacillus bacteria in the intestinal microflora of broiler chickens.

Introduction

The use of antibiotics and other antimicrobials has been practiced for many years to enhance growth performance, disease prevention and efficient use of feeds in the livestock feed industry (Barton, 2000; Gaskins et al. 2002). It is a growing concern about the potential of antibiotics in livestock feeds due to the increasing number of antibiotic-resistant pathogens in human and animals (Williams and Heymann,1998). Therefore, it is necessitated to find effective alternatives to antibiotic feed ingredients as prophylactic antibacterial and growth promoters (Bach Knudsen, 2001), especially after the recent ban of antibiotic use as growth promoters in Bangladesh. The application of a wide range of plant extracts especially sea plants and other natural substances to enhance animal health and performance has been documented for a long time due to their anti-inflammatory, immunomodulatory (Teas et al., 1984), antioxidant and antibacterial activities (Rhodes, 1996). Yoshizawa, et al. (1993) reported that algae extract activated the macrophages and increased the pro-inflammatory cytokine production of laboratory animals.  However, very limited information is available about the use of Chlorella as an alternative to antibiotic feed supplement to promote growth, immune characteristics and intestinal microbial population of broiler chicken. Therefore, the present study was conducted to determine the effect of dietary supplementation of Chlorella on the growth performance, immune characteristics, and intestinal microflora population of broiler chickens compared with an AGP.

 

Materials and Methods

A total of 600 1-d-old male broiler chicks (Ross×Ross) was randomly assigned into five dietary treatments with four replicate pens (30 birds/replicate pen). A corn-soybean meal basal diet (Control) was formulated, and 0.1% virginiamycin, a streptogramin class of antibiotic as antibiotic growth promoters (AGP), 1.0% dried Chlorella powder (DCP), 1.0% Chlorella growth factor (CGF), and 1.0% fresh liquid Chlorella (FLC) were added to the basal diet to form five dietary treatments. The basal diet was formulated to meet the National Research Council requirements and was fed during the experiment in 2 phases, wk 0 to 3 and wk 4 to 5. All birds were raised in a rice hull-littered floor pens (0.093m²/bird) in an environmentally controlled room. Continuous lighting was provided throughout the experimental period. The initial room temperature was 32°C, and reduced by 3°C each week until 35 d of age. Birds were allowed free access to feed and water throughout the feeding period. All procedures were approved by the Animal Care and Welfare Committee of the National Institute of Animal Science, Rural Development Administration, Republic of Korea.

 

Results and Discussion

No significant differences were found among the treatments for feed intake and feed conversion of broiler chickens during the experimental period, but the BW gain was significantly higher (P<0.05) in AGP and Chlorella supplemented groups than those of the control group (Table 1). The number of white blood cells (WBC) was significantly higher (P<0.05) in broilers fed FLC compared to DCP, and the number of lymphocytes (Ly) was also significantly higher (P<0.05) in FLC compared to AGP and DCP; however, supplemental AGP and Chlorella had no effect on other blood leucocytes of broiler chickens (Table 2). Dietary supplementation of Chlorella significantly (P<0.05) increased the plasma IgA concentration of chicks compared to AGP and control. In addition, plasma IgM concentration was higher in DCP and FLC than the control, and plasma IgG concentration was also higher in FLC compared to other treatments (Table 3). Supplemental AGP and various forms of Chlorella did not affect the E. Coli and Salmonella population in the cecal microflora of broiler chicks, but the population of Lactobacillus was significantly increased (P<0.05) when birds were fed FLC (Table 4).

 

 

 

 

 

Conclusions and Recommendations

  1. Dietary supplementation of FLC improves BW gain, immune characteristics, and the production of Lactobacillus bacteria in the intestinal micro flora of broiler chickens.
  2. The inclusion of up to 1% of FLC in the conventional diets of young broiler chicks might improve the development of the digestive tract and growth performance.
  1. It may be beneficial to supplement the diets of broiler chickens with FLC in the absence of AGP.

Bibliographic references

 
Author/s
Hossan Md. Salim is a Poultry Nutritionist and is currently working as Postdoctoral Professor at the Department of Animal Science of the University of Manitoba, Canada.
 
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