Antimicrobial
resistance (AMR) is a major threat to global public health. It is largely
caused by the overuse of antibiotics in human medicine and agriculture. In
intensive poultry production most antibiotics are used as antimicrobial growth
promoters and/or used as prophylactic and metaphylactic treatments to healthy
animals. Reducing such antibiotic interventions is crucial to lowering the
incidence of AMR. However, antibiotic reduction often results in undesirable
performance losses. Hence alternative solutions are needed to boost poultry
performance. Phytomolecules have antimicrobial, digestive, anti-inflammatory
and antioxidant properties, which could make them key to closing the
performance gap.
POULTRY PERFORMANCE DEPENDS ON
INTESTINAL HEALTH
Poultry
performance is to a large extent a function of intestinal health. The intestines
process nutrients, electrolytes and water, produce mucin, secrete
immunoglobulins and create a barrier against antigens and pathogens.
In addition,
it is an important component of the body’s immune defense system. The intestine
has to identify pathogens and reject them, but also has to tolerate harmless
and beneficial microorganisms. If the intestines do not function properly this
can lead to food intolerance, dysbiosis, infections and diseases. All of these
are detrimental to feed conversion and therefore also to animal performance.
Antibiotics
reduce the number of microorganisms in the intestinal tract. From a performance
point of view this has two benefits: first, the number of pathogens is reduced
and therefore also the likelihood of diseases; second, bacteria are eliminated
as competitors for the available nutrients. However, the overuse of antibiotics
not only engenders AMR: antibiotics also eliminate probiotic bacteria, which
negatively impacts the digestive tracts’ microflora.
Products to
boost poultry performance may be added to their feed or water. They range from
pre- and probiotics to medium chain fatty acids and organic acids to plant
extracts or phytomolecules. Especially the latter have the potential to
substantially reduce the use of antibiotics in poultry farming.
PHYTOMOLECULES
ARE PROMISING TOOLS FOR ANTIBIOTIC REDUCTION
Plants
produce phytomolecules to fend off pathogens such as moulds, yeasts and
bacteria. Their antimicrobial effect is achieved through a variety of complex
mechanisms. Terpenoids and phenols, for example, disturb or destroy the
pathogens’ cell wall. Other phytomolecules inhibit their growth by influencing
their genetic material. Studies on broilers show that certain phytomolecules
reduce the adhesion of pathogens such as to the wall of the intestine.
Carvacrol and thymol were found to be effective against different species of Salmonella and Clostridium perfringens.
There is
even evidence that secondary plant compounds also possess antimicrobial
characteristics against antibiotic resistant pathogens. In-vitro trials with
cinnamon oil, for example, showed antimicrobial effects against methicillin
resistant Staphylococcus aureus, as well as against multiresistant E. coli,
Klebsiella pneumoniae and Candida albicans.
Importantly,
there are no known cases to date of bacteria developing resistances to
phytomolecules. Moreover, phytomolecules increase the production and activity
of digestive enzymes, they suppress the metabolism of pro-inflammatory
prostaglandins and they act as antioxidants. Their properties thus make them a
promising alternative to the non-therapeutic use of antibiotics.
Study
design and results
In order to
evaluate the effect of phytomolecules on poultry performance, multiple feeding
studies were conducted on broilers and laying hens. They were given a
phytogenic premix (Activo®,
EW Nutrition GmbH) that contains standardized amounts of selected
phytomolecules.
To achieve
thermal stability during the feed processing and a targeted release in the
birds’ gastrointestinal tract, the product is microencapsulated. For each , the
studies evaluated both the tolerance of the premix and the efficacy of
different dosages.
Study
I: Evaluation of the dose dependent efficacy and tolerance of Activo© for
broilers
Animals: 400 broilers; age: 1-35 days of age
Feed: Basal starter and grower diets
Treatments:
– No supplement (negative control)
– 100 mg of Activo® /kg of feed
– 1.000 mg of Activo® /kg of feed
– 10.000 mg of Activo® /kg of feed
Parameters: weight gain, feed intake, feed conversion ratio, health status, and blood parameters
Animals: 400 broilers; age: 1-35 days of age
Feed: Basal starter and grower diets
Treatments:
– No supplement (negative control)
– 100 mg of Activo® /kg of feed
– 1.000 mg of Activo® /kg of feed
– 10.000 mg of Activo® /kg of feed
Parameters: weight gain, feed intake, feed conversion ratio, health status, and blood parameters
Results: The trial group given the
diet supplemented with 100 mg/kg Activo® showed
significant improvements in body weight gain during the starter period (+4%)
compared to the control group. Additional significant improvements in feed
conversion ratio (FCR) in the growing period (+4%) resulted in an overall
improvement in FCR of 3%. At a 1.000 mg/kg supplementation, a significant
improvement in FCR of 6% was observed over the entire feeding period.
Hematological parameters were within the reference range of healthy birds when
feeding up to 10,000 Activo®/ kg of feed.
Study
II: Evaluation of the dose depending efficacy and tolerance of Activo© for
laying hens
Animals:
200 hens; age: 20 to 43 weeks
Feed: basal diet for laying hens
Treatments:
– No supplement (negative control)
– 100 mg of Activo®/ kg of feed
– 250 mg of Activo®/ kg of feed
– 500 mg of Activo®/ kg of feed
– 5.000 mg of Activo®/ kg of feed
Parameters: weight gain, feed intake, feed conversion ratio, health status, and blood parameters
Feed: basal diet for laying hens
Treatments:
– No supplement (negative control)
– 100 mg of Activo®/ kg of feed
– 250 mg of Activo®/ kg of feed
– 500 mg of Activo®/ kg of feed
– 5.000 mg of Activo®/ kg of feed
Parameters: weight gain, feed intake, feed conversion ratio, health status, and blood parameters
Results: Inclusion levels from 100
mg/kg of Activo® onwards improved laying performance, egg mass and egg weight
and reduced FCR compared to the control group. Results recorded for
hematological parameters were within the reference range of healthy birds when
feeding up to 5.000 mg Activo®/ kg of feed.
Study
III: Evaluation of the dose-dependent effects of Activo© for
coccidiosis vaccinated broilers
Animals:
960 broiler chickens; age: 42 days
Feed: Standard starter and finisher feed
Treatments:
– No supplement (negative control)
– 50 g of Activo® /US ton of feed
– 100 g of Activo® /US ton of feed
– 150 g of Activo® /US ton of feed
– 200 g of Activo® /US ton of feed
– 250 g of Activo® /US ton of feed
– Antibiotic growth promoter (AGP)(positive control)
Parameters: weight gain, feed efficiency
Specific: In order to represent field conditions, the birds were challenged with used, homogenized litter.
Feed: Standard starter and finisher feed
Treatments:
– No supplement (negative control)
– 50 g of Activo® /US ton of feed
– 100 g of Activo® /US ton of feed
– 150 g of Activo® /US ton of feed
– 200 g of Activo® /US ton of feed
– 250 g of Activo® /US ton of feed
– Antibiotic growth promoter (AGP)(positive control)
Parameters: weight gain, feed efficiency
Specific: In order to represent field conditions, the birds were challenged with used, homogenized litter.
Results: A clear dose response for both
body weight gain and feed efficiency was observed (see Figure 1): the more
phytogenic premix given, the better the birds’ performance. The group with 200g
of Activo® /US ton of feed showed similar performance levels than the positive
control group supplemented with AGP.
Figure 1: Dose-dependent effects of for coccidiosis vaccinated broilers
Study
IV: Evaluation of the dose-dependent effects of Activo© for
laying hens
Animals:
40 hens; age: week 20 to 43
Feed: basal diet for laying hens
Treatments:
– No supplement (negative control)
– 100 mg of Activo®/ kg of feed
– 250 mg of Activo®/ kg of feed
– 500 mg of Activo®/ kg of feed
– 5.000 mg of Activo®/ kg of feed
Parameters: weight gain, feed intake, egg production, feed conversion ratio, health status
Duration: 168 days of feeding period
Feed: basal diet for laying hens
Treatments:
– No supplement (negative control)
– 100 mg of Activo®/ kg of feed
– 250 mg of Activo®/ kg of feed
– 500 mg of Activo®/ kg of feed
– 5.000 mg of Activo®/ kg of feed
Parameters: weight gain, feed intake, egg production, feed conversion ratio, health status
Duration: 168 days of feeding period
Results: The laying hens showed a
higher laying rate when fed with a higher concentration of phytomolecules
(Figure 2). Similarly improved results were observed for the feed efficiency.
The more phytogenic premix added to their diet the better feed efficiency
(Figure 3).
Figure 2: Dose-dependent effects of Activo© on laying rate in laying hens
Figure 3: Dose-dependent effects of Activo© on feed efficiency in laying hens
In
conclusion, all four studies indicate that the inclusion of phytomolecules in
broilers’ and laying hens’ diet improves their performance. Increasing levels
of a phytogenic premix (Activo®) significantly increased the production
parameters for both groups. These improvements might bring performance in
antibiotic-free poultry production on par with previous performance figures
achieved with antimicrobial growth promoters.
The studies
also showed that microencapsulated phytogenic premixes are safe when used in
dose ranges recommended by the suppliers. No negative effects on animal health
could be observed even at a 100 fold / 50 fold of the recommended inclusion
rate in diets for broiler or laying hens, respectively. Thanks to their
positive influence on intestinal health, phytomolecules thus boost poultry
performance in a safe and effective way.
By
Henning Gerstenkorn
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