Text by Ir. Bart Molenaers
In
breeders, fertility is one of the most important (if not the most important)
attributes to ensure profitability. Fertility percentages will dictate the
profitability of the hens. Infertility is a major economic factor for the
sector.
A decrease in fertility is thought to be mainly an age-related problem in cockerels (Khan, 2011; Kazemizadeh et al., 2019).
A decrease in fertility is thought to be mainly an age-related problem in cockerels (Khan, 2011; Kazemizadeh et al., 2019).
Figure 1: chicken semen (Santiago-Moreno, J.; 2015)
There are several factors which induce a decrease in sperm quality,
such as a dysfunction in Sertoli cells, which play a role in production of
sperm, weight gain of the roosters, a reduced sperm concentration, a lower
testosterone level and a declined total antioxidant capacity of semen, which
all contribute to a decrease fertility rate in aged roosters (Kahn, 2011;
Kazemizadeh et al.; 2019; Ansari et al.; 2017; Borghei-Rad et al., 2017).
PUFA’s
The plasma membrane of sperm cells consist out of a very high
concentration poly-unsaturated fatty acids (PUFA’s). Most of those lipids
belong to the omega-6 fatty acids (figure 2) Those lipids are involved in a
series of internal processes which all influence fertility. They, for example,
play a role in different stages of sperm maturation, capacitation and acrosome
reaction, all important processes in fertilization (Khan, 2011; Kelso et al., 1996). The high concentration of
PUFA’s in sperm cells indicate that sperm membranes need to have a high
fluidity and flexibility to be motile and to fuse with the egg cell.
Figure 2. while
normal red blood cells (RBCs) have a concentration of less than 60% PUFA’s in
their membrane, the sperm cell membrane has a concentration of PUFA’s higher
than 80%. This, in combination with a high concentration of free radicals (also
produced by the mitochondria in the sperm cells), makes them very vulnerable
for free radical attacks.
This high concentration of PUFA’s makes the sperm cells very
vulnerable for free radical attacks, especially by reactive oxygen species (ROS).
An example of such ROS is hydrogen peroxide. High levels of hydrogen peroxide
will result in lipid degeneration (peroxidation) and ultimately cell death.
More information about
free radicals and ROS can be found on “what are free radicals?” available on www.mercordianimalcare.com.
Antioxidants, the “soldiers” to
protect sperm cells
Living creatures have their own system to keep the free radical
concentration in balance. They produce antioxidants, molecules which are able
to neutralize free radicals without inducing damage. Vitamin C and vitamin E
are examples of those antioxidants. However, whenever the body is in unbalance
(stress, disease, high production status or old age), the concentration of
antioxidants, produced by the body, will not be sufficient to cope with all the
free radicals and the body will come in unbalance.
In terms of sperm quality, it has been shown that the fertility rate
in roosters reaches a maximum around 37 weeks of age and decreases after week
45-50 (Leeson & Summers; 2010). With aging, the production of antioxidants
decreases inside the body, while the production of ROS increases (Kelso et al., 1996). An extra addition is
therefore needed when the rooster ages. We make a summary of some very
promising antioxidants.
Vitamin
E
Vitamin E is one of the main antioxidants concerning fertility.
Vitamin E attacks free radicals and reacts with them, producing ROOH groups,
which are not harmful anymore. Lin et al.
(2005) showed that a dietary increase in the vitamin E content of semen
resulted in a significant reduction of lipid peroxidation of the semen, and
therefore resulting in better semen quality. Age related decrease of the
fertility in roosters is associated with a decreased level of vitamin E in the
testes (Surai et al. 1997, Khan,
2011).
A summary of all the effects of vitamin E on fertility can be seen
in figure 3.
Figure 3: the effect of vitamin E deficiency on fertility traits in
poultry
Selenium
Selenium is not a vitamin, it is a trace element. This trace element
has many important roles in the body, one of them is an antioxidant function. Selenium
can work as an antioxidant through its role as a component of the enzyme
glutathione peroxidase. It helps in protecting and stabilising the sperm cell
membrane (Khan, 2011). Dimitrove et al.
(2007) showed that selenium-supplemented sperm had better characteristics of
storage, sperm motility and slow release of total lipids and phospholipids from
spermatozoa to seminal plasma during storage.
Vitamin
C
Everybody knows vitamin c as an antioxidant which protect the animal
during heat stress. This antioxidant can be synthesized by the animal itself
and will be sufficient in normal conditions. However, physiological stressors
like heat, disease or overcrowding may augment the poultry requirement for
vitamin C (Nockels, 1984).
There are some studies which indicate that vitamin C can be helpful
in maintaining a good fertility level, especially during heat stress (Mc Daniel
et al., 1998, McDaniel et al., 1995). The exact mechanism
however is not known
Curcuma
Curcuma, or turmeric (curcuma longa) is a member of the ginger
family (Zingiberaceae) and is a great source of a specific type of
antioxidants: the phenolic compounds called curcuminoids.
It is believed that curcuma has great anti-inflammatory effects. The
protective effects of curcumin on lipid peroxidation by scavenging radicals
have been well documented (Kazemizadeh et
al., 2019)
Figure 4: curcuma longa
There are many studies which indicate a beneficial effect of curcuma
on meat quality and liver health of the birds, but there is also a particular
interest for its fertility enhancing effects. In a test of Kazemizadeh et al. (2019), there were clear improvements
in semen concentration and plasma membrane functionality after treatment with
curcuma for 4 weeks.
Due to its structural form, curcumin, one of the phenols, has a
strong scavenging capacity for free radicals as superoxide radicals, hydrogen
peroxide, reducing iron complexes, as also a reduction in lipid peroxidation (Kazemizadeh
et al., 2019).
Furthermore, curcumin is also associated with improved semen
concentration and production of sperm with normal morphology ( Kazemizadeh et al., 2019). So, as you can see,
curcuma, is not only good for liver health, but certainly plays its role in
sperm quality too!
Infinite VH®
potent herbal blend with among other ingredients, Vitamin E, Selenium and curcuma.
MercoselenE®
stable source of Vitamine E and selenium
C.Power® HC
reliable source of stabilized, protected Vitamin C
References
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Borghei-Rad, S.M.; Zeinoaldini, S.; Zhandi, M.; Moravej, H. &
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