Experimental design to assess the effect of maternal transition of omega-3 fatty acids on
hatchability, chick quality and performance till slaughter.
A.Koppenolab, E. Deleziea, N. Everaertb, J. Buyseb
a
ILVO Animal Sciences Unit, Scheldeweg 68, 9090 Melle, Belgium; bKULeuven, Dep. Biosystemen,
Afdeling Dier-Voeding-Kwaliteit, Kasteelpark Arenberg 30 - bus 2456, 3001 Heverlee, Belgium
Introduction
Because of advances in genetic selection, management, and nutrition, modern-day meat-type broiler
chickens have faster growth rates and higher metabolic rates than do egg laying strains of hens. These
features promote an increased workload on the cardiovascular system, predisposing broiler birds to
metabolic and cardiovascular disorders (Julian et al., 2005).
Diets high in n-6 fatty acids, characteristic of modern day poultry rations, are considered an important
factor contributing to increased incidence of diseases involving inflammatory and coronary vascular
diseases in broilers (Simopoulos et al., 2008). n-3 polyunsaturated fatty acids (PUFA) instead may exhibit
cardio protective effects via incorporation into cell membrane phospholipids and by alterations of
eicosanoid metabolism (De Caterina et al., 2003).
Dietary fatty acids provided to the hens can be built into the yolk and therefore be available to the
progeny early in their development. During the 21 days of the incubation period, over 80% of yolk lipids
is absorbed by the developing chick embryo , serving as a source of energy and essential fatty
acids(Noble et al., 1990). Embryo livability and hatchability rate decreases with lack of essential fatty
acids (Menge, 1968). In addition to providing energy to the embryo, yolk fatty acids are needed for the
synthesis of membrane phospholipids in the growing tissue of the embryo. They contribute to embryonic
structural phospholipids through provision of long chain (>20C) PUFA such as arachidonic acid (AA,
20:4 n-6), eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3). Previous
studies reported that upon incubation of a fertile egg, the tissue fatty acid composition of the embryo and
the hatched chick reflected the egg yolk fatty acid profile (Cherian et al., 1991). Similarly, tissues (e.g.
cardiac, hepatic, immune and brain) of growing chicks hatched from n-3 fatty acid-rich eggs retained
significantly higher levels of these fatty acids (Cherian et al., 2007).
Hypothesis
In the present experiment is hypothesized that prehatch as well as posthatch enrichment with long chain
PUFA provides more available DHA and EPA for development and eicosanoids to affect the birds’ health
and performance. Therefore the effects of long chain PUFA’s on the fertility, hatchability, embryonic
mortality, egg quality, fatty acid composition of egg yolk and organs and performance of the progeny will
be studied.
Material and methods
Parent stock
528 Ross 308 broiler breeder hens will be divided over 16 pens receiving 4 different dietary treatments.
They will be fed diets containing 1.5% of soybean oil rich in n-6 fatty acid, a mixture of 0.5% soybean oil
and 1% DHA oil high in n-3 fatty acid (EPA=DHA), a mixture of 0.73% soybean oil and 0.77% tuna oil
high in n-3 fatty acid DHA, or a mixture of 0.63% soybean oil and 0.87% fish oil high in n-3 fatty acid
EPA. Hens will be fed the 4 different treatments from 6 weeks of age on. At 21 weeks 1 cockerel per 10
hens will be placed in the pens to achieve fertilized eggs. Eggs will be collected and counted daily.
Every two weeks eggs will be weighed to calculate laying percentage and feed conversion rate.
Table 1. Diet formula fed to breeder hens.
Treatment
A (n-6)
B (n-3)
C (DHA)
D (EPA)
n-6/n-3
7.60
1.60
2.15
1.88
EPA/DHA
/
0.80
0.22
2.16
Soybean Oil
1.50%
0.50%
0.73%
0.63%
DHA Oil
Tuna Oil
Fish Oil
1.00%
0.77%
0.87%
A (n-6), B (n-3), C (DHA) and D (EPA) represent a wheat-corn meal-based maternal (breeder hen) diet
supplemented with 1.5% soybean oil, a mixture of 0.5% soybean oil and 1% DHA oil, a mixture of 0.73% soybean
oil and 0.77% Tuna oil, or a mixture of 0.63% soybean oil and 0,87% fish oil, respectively. The breeder hen diets
are isonitrogenous and isocaloric.
Incubation to generate offspring
Two hundred fifty fertile eggs per treatment will be collected and incubated at 3 different times, being at
28 - 43 - 58 weeks of age. At 18 days of incubation, the eggs will be candled, and only eggs with fully
developed embryos will be transferred to hatching baskets until 21 days of incubation. Hatched chicks
will be counted and sexed, and those eggs that did not hatch will be removed from the hatcher and also
counted.
Eggs from each treatment will be collected randomly and the yolks will be separated from 10 eggs each
for lipid and fatty acid analysis.
Six additional incubations will be performed each 3 weeks starting at an age of 33 weeks to assess
embryonic mortality, chick quality, fertility, hatchability, fatty acid composition of yolk.
On 3 different moments ( 29 – 44 – 59 weeks of age) yolk weight, egg shell weight, albumen weight, yolk
colour and haugh units will be assessed.
Progeny
Male hatched chicks from each treatment will be weighed and subsequently divided into six replicates of
30 chicks per maternal dietary treatment and placed in pens containing deep litter (n=180/treatment).
The progeny will be raised until 39 days of age on a commercial diet. Diet and water will be provided ad
libitum. Live weight and feed intake will be measured weekly, to calculate the feed conversion rate.
Biweekly, blood samples will be taken from 12 animals per treatment to analyze plasmametabolites. At
the same time, 12 animals per treatment will be euthanized at day 14,28 and 39 to collect their
immunological organs and liver for fatty acid analysis.
References
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