2. Contents
Host defense peptides HDPs.
Host defense peptides HDP and sodium butyrate.
Trophic effect of sodium butyrate.
Antibacterial effect of sodium butyrate.
Other effects of sodium butyrate.
3. Contents
Host defense peptides HDPs
Host defense peptides HDP and sodium butyrate
Trophic effect of sodium butyrate
Antibacterial effect of sodium butyrate
Other effects of sodium butyrate
4. What is Host Defense Peptides HDPs?
Host defense peptides (HDPs), also known as antimicrobial
peptides, are present in all species and constitute a critical
component of the innate immunity.
5. Cont. …
There are two major families of HDPs in vertebrates;
1. Defensins
2. Cathelicidins
The chicken genome was recently found to encode a total of;
1) 14 b-defensins known as AvBD1-14
2) 4 cathelicidins, namely fowlicidins 1–3 and cathelicidin-
B1.
6. Cont. …
In chicken, AvBDs and cathelicidins are expressed in a wide
range of tissues;
– Bdefensins in liver , digestive, respiratory, and reproductive
tracts.
– Cathelicidins in bone marrow or bursa.
8. Host Defense Peptides
Antimicrobial Activities
HDPs possess broad-spectrum antimicrobial activities against:
1. Bacteria
2. Protozoa
3. Enveloped virus
4. Fungi
mainly through direct binding and lysis of microbial membranes.
9. Cont. …
Because of such physical interactions, it is extremely difficult
for pathogens to develop resistance to HDPs.
Many chicken HDPs have been found to possess potent
antibacterial activities against a broad range of bacteria
including Salmonella.
10. Host Defense Peptides
Immune Stimulation
HDPs have a strong capacity to modulate the innate immune
response by inducing chemotaxis and activation of various
types of leukocytes.
11. Host Defense Peptides
Because of these pleiotropic effects, HDPs have been actively
explored as a new class of therapeutic agents against
antibiotic-resistant microbes and other inflammatory
diseases.
12. Contents
Host Defense Peptides HDPs
Host Defense Peptides HDP and Sodium Butyrate
Trophic Effect Of Sodium Butyrate
Antibacterial Effect Of Sodium Butyrate
Other effects Of Sodium Butyrate
13. In Vivo Induction Of
The Avbd9 Gene Expression
In The Intestinal Tract Of Chickens By Butyrate
14. Sodium Butyrate and HDPs
Butyrate, a major species of short-chain fatty acids produced
by bacterial fermentation of undigested carbohydrates in the
intestine, was recently found to be capable of inducing HDP
expression in humans, rabbits and poultry.
15. Study Design
Birds profile:
Two-day-old male Cornish Rock broilers
Treatment
Feed with standard ration with or without supplementation of
0.1% and 0.2% butyrate for 2 days.
Evaluation:
Crop, cecal tonsil and cecum were collected from each bird and
the AvBD9 gene expression was evaluated by real-time PCR.
16.
17. Reduction of the S. enteritidis titer in the cecal
contents of chickens following oral supplementation
of butyrate
18. Study Objective
To examine the effect of supplementing butyrate in the feed
on the titer of Salmonella enteritidis in the cecum following
experimental infections.
19. Study Design
Birds profile:
20-day old male broilers were equally divided into two groups,
each of 10.
Treatment
Feed with a standard antibiotic-free diet mixed with and without
0.2% sodium butyrate for 2 days.
20. Cont. …
Challenge
Birds were then inoculated with 1X10 log 6 CFU of S. enteritidis
phage type 13a and continued with butyrate feeding for another
4 days.
Evaluation
The S. enteritidis titer in the cecal content was quantitated from
each bird by serial plating on Brilliant Green agar plates
containing 20 mg/ml nalidixic acid.
21.
22. Study Design
This trial was similarly conducted with an additional group of
10 broilers fed with 0.1% butyrate.
Each dot represents the bacterial titer from a bird and the
solid line represents the median value of each treatment.
Brackets indicate the statistical significance of differences
23.
24. Contents
Host Defense Peptides HDPs
Host Defense Peptides HDP and Sodium Butyrate
Trophic Effect Of Sodium Butyrate
Antibacterial Effect Of Sodium Butyrate
Other effects Of Sodium Butyrate
25. Trophic Effect Of Sodium Butyrate
Sodium butyrate is a preferred source of energy for the
enterocytes.
This will result in:
1. Better development of the intestinal villi.
2. Stronger gut lining.
26. Study Design
Trial Objective
To evaluate the influence of sodium butyrate on digestibility of a
corn-soya diet, as well as villi development.
Birds Profile
A total of 750 Cobb 400 one day old broiler chickens.
Treatments
27. Cont. …
The trial evaluated 3 treatments:
1. Control (no additives)
2. 0.5 kg/t of Product X (92% sodium butyrate)
3. 1 kg/t of Product X.
Evaluations
1. The digestible energy of the diet
2. The digestibility of the protein
3. The lengths and widths of the villis
28. Digestibility of Energy
Energy kcal/kg
3,105
3,264
3,285
Digestibility of Energy
Control Product X 0.5g/kg Product X 1.0g/kg
30. Villi Length
21 Days Old mm
Villi Length 21 Days Old mm
0.98
1.52
1.24
Villi Length 21 Days Old mm
Control Product X 0.5g/kg Gustor 1.0g/kg
31. Villi Length
42 Days Old mm
Villi Length 42 Days Old mm
0.94
1.31
1.12
Villi Length 42 Days Old mm
Control Product X 0.5g/kg Gustor 1.0g/kg
32. Villi Width
21 Days Old µm
Villi Width 21 Days Old µm
224.70
260.80
197.70
Villi Width 21 Days Old µm
Control Product X 0.5g/kg Gustor 1.0g/kg
33. Villi Width
42 Days Old µm
Villi Width 21 Days Old µm
138.50
314.20 317.20
Villi Width 42 Days Old µm
Control Product X 0.5g/kg Gustor 1.0g/kg
34. Conclusion
The digestible energy of the diet and the digestibility of the
protein were significantly improved by the addition of sodium
butyrate.
The lengths and widths of the villi were also positively
affected by the addition of butyrate in the diet.
From this trial and previous research, it was concluded that
inclusion of butyrate in the diet improves the digestibility of
energy and protein by increasing intestinal absorption surface
35. Contents
Host defense peptides HDPs
Host defense peptides HDP and sodium butyrate
Trophic effect of sodium butyrate
Antibacterial effect of sodium butyrate
Other effects of sodium butyrate
36. VFA
Antibacterial Effect
It has been demonstrated that VFAs can inhibit the growth of
bacteria of the group of Enterobacteriaceae (Salmonella,
Escherichia coli …).
Mechanism of action
This is because the undissociated form of these acids can
freely diffuse across the bacterial membrane.
Once inside the cytoplasm of the bacteria, the acid
dissociates, thus releasing free hydrogen ion and reducing the
pH, which causes internal cell damage.
37. Butyric Acid
In this respect, butyric acid performs very well.
Hume et al. (1993) showed that butyric acid has a higher
diffusion coefficient than other acids with a shorter chain,
which allows it to pass through the bacterial membrane more
easily.
Galfi and Neogradi (1995) found that the concentration of
butyrate required to reduce the growth of E. coli by 50% is
much lower than the concentration of the other volatile fatty
acids, acetate and propionate.
38. Butyric Acid Vs Other Fatty Acids
Van Immerseel (2004) observed that
butyric acid was the most effective
acid to help controlling Salmonella
enteritidis in broilers after a challenge.
Number of colony forming units (CFU) per gram of ceca
at day 8 after hatch of chickens orally inoculated with
1,000 CFU Salmonella enteritidis at days 5 and 6 and
given feed supplemented with different organic acids
(Adapted from Van Immersel, 2004)
39. Butyric Acid
Selective Action
It should be also noted that the antibacterial effect of
butyrate is selective.
For instance, in 1990, Galfi and Bokori demonstrated that
butyric acid favors the development of lactic flora which
competes against the enteropathogenic one (Clostridia, E.
coli, Coccidiae…).
40. Butyric Acid
Coccidia
Leeson et al. (2005) also observed that birds receiving butyric
acid before coccidial oocyte challenge showed higher weight
gain following the challenge compared with birds that
received a control feed.
41. Butyric Acid
Salmonella
One very unique feature of butyric acid is its ability to
negatively affect the virulence of pathogenic bacteria such as
Salmonella.
42. Cont. …
To infect an animal host, Salmonella must penetrate the
intestinal epithelial barrier.
This very important step is called invasive phase and requires
specific genes inside the bacterium.
The invasion genes are located on the so-called
“pathogenicity island” and are encoding some regulatory
proteins, some structural components of a needle complex,
plus some effector proteins, which make possible the entry of
Salmonella into the epithelial cells.
43. Cont. …
The pathogenicity island itself is activated by another protein
called HilA, which can be environmentally regulated.
Different publications have shown that butyrate and
propionate can reduce the pathogenicity of Salmonella
Typhimurium or Salmonella Enteritidis, whereas other acids
such as acetic or formic are actually promoting the invasion of
epithelium cells by the bacteria (Durant et al., 2000 - Van
Immerseel et al., 2003 - Lawhon et al., 2005 - Gantois et al.,
2006 - Huang et al., 2008).
44. Cont. …
The exact mode of action of butyrate in the bacterial cell is
still unknown but it seems it can interfere with the genetic
expression and results in a down regulation of the
pathogenicity island, regulating the invasive phenotypes of
Salmonella.
45. Contents
Host defense peptides HDPs
Host defense peptides HDP and sodium butyrate
Trophic effect of sodium butyrate
Antibacterial effect of sodium butyrate
Other effects of sodium butyrate
46. Other effects Of Sodium Butyrate
1. Stimulation of Pancreatic Secretions
Although other organic acids also produced this effect,
butyrate seems to be the one that causes the greatest
stimulation of pancreatic secretions.
Katoh and Tsudo (1984) observed that the injection of
sodium butyrate in pigs resulted in greater stimulation of
pancreatic fluid secretion and increased amylase
secretion.
47. Cont. …
Katoh et al. (1989) demonstrated that intravenous injection of
sodium butyrate in calves resulted in a higher secretion of
pancreatic juice and greater release of proteins (particularly
amylase) when compared to acetate and propionate.
48. Cont. …
2. Stimulation of Insulin Secretions
Sano et al. (1995) also observed that the administration of
butyrate caused an increase in the plasmatic levels of
insulin, which normally results in higher amount of energy
and proteins deposited in the animal tissues.
49. Cont. …
3. Improves Absorption Of Electrolytes
Sodium butyrate also improves the absorption of
electrolytes and reduces the incidence of diarrhoea (Galfi,
1989).
Editor's Notes
Defensins are categorized by the presence of six conserved cysteine residues in the C-terminal mature sequence.
Cathelicidins consist of a conserved cathelin domain in the pro-sequence with a highly diversified C-terminal mature sequence.
All AvBDs are densely clustered on chicken chromosome 3q, whereas cathelicidin genes are located on chromosome 2p.