Impacts of Breeder Age , Storage Time and Setter Ventilation Program on Incubation and Post-Hatch Performance of Broilers

The impacts of breeder age (32 and 55 weeks), egg storage time (2-12 days), setter ventilation program (control-test) on incubation and post-hatch performance of broilers were investigated in this study. Young (Y) and old (O) breeders’ hatching eggs were incubated in two different setters operated by two different ventilation programs as control (C) and test (T). Incubation took place after a short (S) and long (L) time of storage in this study. According to the trial design, eight treatment groups were as YSC, YST, YLC, YLT, OSC, OST, OLC and OLT. In total 9600 eggs and 6400 chicks were used. Early stage embryonic mortality (ED) rates were lower and accordingly hatchability of fertile eggs (HF) were higher (p<0.05) in YS than the other treatment groups. In contrast, incubation performance in eggs hatched in C and T programs were found to be similar. However, interaction between treatments were significant (p<0.05) and ED and HF were significantly (p<0.05) improved at OC. Liveability in growing period was affected (p<0.05) by breeder age but it wasn’t affected by storage time and incubation program. Higher post-hatch performance was achieved in chicks of OST but differences between groups weren’t significant except for chick weights in comparison by breeder age. However, interactions between treatments were significant (p<0.05) and reached the highest post-hatch performance in YST (p<0.05). In conclusion, the long time storage of old breeders’ eggs improved incubation and posthatch performance when they were incubated at test program.


INTRODUCTION
The hatchery is one of the most important and fragile integral part of the poultry production chain that requires serious amount of investment.The relationship between incubation and growing period began to increase gradually through the use of high-yielding breeds and hybrids.To see the best performance characteristics of broiler chicks in the field, a lot of attention should be paid to the hatchery.In the hatcheries, chick production is carried out based on information about the physiology of embryonic development.The whole immune system and body development of chicks takes place in the hatcheries with contribution of nutritional and genetic aspects of the breeders.Thus the hatchery has an important impact on liveability and post-hatch performance of birds.According to incubation research data (embryonic mortality rate, hatchability of fertile eggs, hatchability etc.) incubation affects the results of the whole production chain.Thus it is very important to analyse and improve the incubation results (Boerjan, 2011).
Incubation performance is affected by genetics, breeder age, egg quality, air pressure, oxygen demand, temperature, humidity, turning, storage time, storage conditions, management conditions of breeders and breeders' health conditions.Performance of the incubation sequence can also be determined by economic criteria such as fertility and hatchability of fertile eggs.The post-hatch performance is influenced by factors such as genetics, breeder age, incubation process, management conditions of breeders and condition of the growing house, season and disease.All these factors of management may have some effect on criteria such as average slaughter weight, feed conversion rate, liveability and European productivity index (Turkoglu et al., 2014).
Reaching to the highest incubation performance and achieving high quality chicks in the hatchery depends on reducing deviations in egg quality and the embryonic development.Researches are being taught to understand and identify natural variations in egg quality with embryonic development and some equipment are being developed to provide a uniform incubation.English Buckeye and Belgian Petersime companies suggest the idea that embryonic development may be encouraged via carbon dioxide (CO 2 ) accumulation.They developed a technology allowing CO 2 to rise for a certain period, then this high level is reduced in a controlled manner by help of infrared CO 2 sensor (Elibol & Turkoglu, 2014).
Researches in the field determined that breeder age, storage time and CO 2 levels affected incubation and post-hatch performance.The increase in breeder age (Mather & Laughlin, 1979;Tona et al., 2004) and storage time (Becker et al., 1968;Butcher 2004;Mather & Laughlin, 1976;Reis et al., 1997;Tona et al., 2004) negatively affects embryonic mortality (Mather & Laughlin, 1979;Bruzal et al., 2000;Ross Tech 2003;Elibol & Brake, 2003) and hatchability of fertile eggs (Mather &Laughlin, 1976 and1979;Mc Daniel, 2000;Tona et al., 2004).Generally, embryonic mortality during the incubation period varies between 3-7% in the early and late stage but it is less than 1% in mid-term (Romanoff, 1949;Salamon & Kent, 2014).Embryonic deaths is associated with storage conditions for early stage, malnutrition or infections for mid-term deficits, deficits in incubator and previous periods for last stage (Hodgetts 1993;Bruzal et al. 2000).Depending on embryonic mortality and hatchability of fertile eggs, it is well known that live weight values are also negatively affected by similar conditions (Reis et al., 1997;Tona et al., 2004).Body weight (Christensen et al., 1996), feed conversion ratio (Hill, 2002) and liveability worsens with increasing storage time and breeder age.However, there are studies showing a difference in live weight values especially of first week (Quintana et al., 2000;Tona et al., 2004) this difference closes subsequently (Bowling & Howarth, 1981;Elibol, 1997).In contrast, different results were obtained through studies on the effects of the CO 2 level in the machine (Everaert et al., 2007;2008).
There are studies that show positive (Ross Tech, 2003) and negative (Taylor, 2000) effects of raising CO 2 levels to a certain level or operating CO 2 control system (Onagbesan et al., 2007).The first studies on the effects of CO 2 during the incubation period reported negative impact on hatchability of chicken eggs when incubator CO 2 levels exceeded 1% during very early incubation (Romanoff & Romanoff 1933;Barrott, 1937).More recent studies have shown that a gradual increase in CO 2 levels up to 1.5% in the first 10 days of incubation enhanced embryo growth, stimulated early hatching and increased hatchability of chicken and turkey eggs (Gildersleeve & Boeschen, 1983;Hogg, 1997;De Smit et al., 2006;Tona et al., 2006) and is shown that this effect changed with strain (De Smit et al., 2008;Tona et al., 2013).When ventilation system of the incubator was not operated and the ventilation holes of incubator were closed for this aim, albumen pH and egg weight loss decreased, embryonic body weight and hatchability increased.Also, earlier hatch (approximately 8,68h) and narrower hatch window was obtained where lesser embryonic mortality (because of a reduction in embryo mal positioning) and higher chick body weight was found.Hormonal levels as triiodothyronine (T 3 ), thyroxine (T 4 ) and corticosterone with records of blood haematology parameters as haemoglobin (Hb), % packed cell volume (PCV) and red blood cell (RBC) count were determined therewithal (De Smit et al., 2008;Fares et al., 2011;Tona et al., 2007;Willemsen et al., 2008).At the same time during the post-hatch period, first week (De Smit et al., 2008) final body weight, body weight gain, feed consumption and feed conversion ratio were shown to be slightly higher (Fares et al., 2011).It was concluded that the effects of high CO 2 levels were found to be differentiating on incubation and post-hatch performance according to applied levels and times, after the first 10 days of incubation period.It was shown that high (9%) CO 2 after 9 th days of incubation increased blood bicarbonate and pH values (Dawes et al., 1971), high (4%) CO 2 between 12 th -18 th days did not change hatching parameters and first week body weight where corticosterone and T 4 levels were found to increase in contrast (Everaert et al., 2007;2008).
Studies to provide more uniform hatchability of fertile eggs and lesser distortions in performance are continuing by improvisations of incubation and posthatch conditions.In particular, to determine the effects of applied processes from breeder farms to hatchery

Impacts of Breeder Age, Storage Time and Setter Ventilation Program on Incubation and Post-Hatch Performance of Broilers
till the slaughter age, and to produce solutions are becoming more and more important.This research was conducted in the light of these information and it was aimed to reach higher hatchability of fertile eggs and reduce the deviations in performance by determining the effects of breeder age, storage time and ventilation program in the setters.

MATERIALS AND METHODS
The impacts of breeder age, storage time and setter ventilation program on incubation and post-hatch performance were examined in this study trial design shown on Table 1.For this purpose, percentage of embryonic mortality and hatchability of fertile eggs as a hatchery criteria and liveability, chick weight (CW), body weights on 41 st day of growing period (BW), daily weight gain (DWG), feed conversion ratios (FCR), European efficiency index (EPEF) data as field criteria were gathered.
In this study, 9600 hatching eggs obtained from young (32 weeks) and old (55 weeks) Ross 308 broiler breeders and 6400 broiler chicks (randomly selected to test house compartment capacity from hatched First, hatching eggs obtained from young and old flocks were divided randomly into two equal parts and stored for 2 and 12 days.Eggs were stored at 18°C temperature and approximately 75% of relative humidity.Later, the same eggs were divided into 2 equal parts and randomly placed in two different setters which were operated at two different ventilation programs (Figure 1 and Table 2).The first setter was operated by normal ventilation program (control), where the certain level of CO 2 in the machine was allowed by deactivating CO 2 control system.The second machine was operated by a different ventilation program (test) to provide rapidly accumulating and increasing CO 2 levels in the machine up to 9 days and later gradually reducing by using CO 2 control system and by arranging the openings of the ventilation flaps.150 eggs were placed on each setter trays and each tray was accepted as a replicate.Accordingly 32 replications (tray) in total have been used as 8 replications per treatment during the incubation stage of the study.

Impacts of Breeder Age, Storage Time and Setter Ventilation Program on Incubation and Post-Hatch Performance of Broilers
Eggs have been placed on different setters till the transfer time (at 18.5 day) and then transferred to the same hatcher and the program recommended by Petersime was applied to all as same.After the completion of the hatching process, culls and unhatched eggs in hatcher trays have been separated for hatch breakout analysis.Early (0-7 day), mid-term (8)(9)(10)(11)(12)(13)(14)(15)(16)(17) and late (18-21) stage embryonic mortality rates and pipped but unhatched embryo rates were detected according to Hodgetts (1993) by opening unhatched eggs.
Treatment chicks have been sexed and vaccinated.Chicks arriving the house were weighed and randomly distributed to the pen as 16 chicks/m 2 (200 chicks/ compartment) stocking density and 50% male+50% female for each subgroup.Totally 4 subgroup were used with 4 replications per treatment during the rearing period.Broiler, 2007) and feed were provided by Bolu Feed Mill of Beypi Inc. Chickens were fed in four phase as follows, 0-10 th , 11-22 nd , 23-35 th and 36-41 st days (Table 3).Feed ingredients and nutrient compositions of compound feeds were analysed to methods were given by AOAC (1990).
Diets were formulated at international standards (NRC, 1994) and grand parent company Feed consumption in each sub-group was determined by weighing the birds at the end of each feeding phase.
Liveability was determined by recording the number of dead chicks (mortality) in sub-groups daily.Treatments were designed to the randomized complete block experiment design.The data were evaluated by using one-way ANOVA (factorial design) and analysed using GLM (General Linear Model) procedures of IBM SPSS 22.0 software package program (SPSS, 2013) Statistical differences among the groups were determined by Duncan's Multiple Comparison Test (F-test) (Duncan, 1955).

RESULTS
Statistical analyses of the data on the incubation and post-hatch performance has been carried out separately and the results are summarized in tables (Table 4, 5 and 6).

Impacts of Breeder Age, Storage Time and Setter Ventilation Program on Incubation and Post-Hatch Performance of Broilers
When the data on the incubation performance was analysed, it was found that breeder age affected early embryonic mortality (ED) and hatchability of fertile eggs (HF) (p<0.05).ED values of young flocks was lower than older one and accordingly HF was higher.It was found that increasing storage time affected ED and late stage embryonic deaths plus pipped and unhatched embryo rate significantly (p<0.05).Because of higher ED and late stage embryonic deaths plus pipped and unhatched embryo rate, lower HF was obtained from 12 days stored eggs than the ones stored for 2 days (p<0.05).No significant differences between ventilation programs have been found about the criteria.Also, interactions between breeder age-setter ventilation program, storage timesetter ventilation program were significant (p<0.05)statistically.It was detected that an improvement were provided in early stage embryonic deaths when hatching eggs of old breeders were incubated in setters operated to test the ventilation program of accumulated CO 2 (Table 4).
Post hatch performance data obtained from old breeders' hatched chicks has been achieved numerically higher from the accumulated CO 2 ventilation program.However, differences between treatments were not found statistically significant (p>0.05)except for the differences between chick weights and liveability.Liveability of young breeder flocks were lower than old breeders in both first week and last week (p<0.05).It was determined that liveability in rearing period was affected by breeder age whereas not affected by storage time and setter ventilation program (Table 5).
The chick weight differences of young and old flocks were high and significant (p<0.05).But then they got closer in time and by the end of rearing period, average live weight and daily weight gain values were similar.

DISCUSSION
This research was designed to obtain higher incubation and growing performance and to reduce the deviation in performance by determining the effects of breeder age, storage time and setter ventilation program.Embryonic deaths and fertile hatchability of fertile eggs (HF) for incubation performance, liveability, and chick weight (CW), body weight (BW), daily live weight gain (DWG), feed conversion ratio (FCR) and European Productivity Index (EPEF) values for growing performance were evaluated.
ED of young flocks and accordingly HF was higher than older flock eggs.Similarly, lower early stage embryonic deaths and late stage embryonic deaths plus pipped and unhatched embryo rates and accordingly higher hatchability of fertile eggs in short time stored eggs have been obtained from experimental data.In contrast, incubation performances of eggs incubated in setters operated to different ventilation program were similar.Also, depending on the important interactions between treatment groups.It has been found that ED and HF were improved, when hatching eggs of old flocks incubated in setter operated to by accumulated CO 2 .Türkoğlu M

Impacts of Breeder Age, Storage Time and Setter Ventilation Program on Incubation and Post-Hatch Performance of Broilers
The results of this study supported the findings of Mc Daniel (1995) showing that early and late stage embryonic mortality is 3-5% and this seems to be consistent with the general statement in this regard.The results of setter ventilation program trial in this study was supported by researches (Ross Tech, 2003) showing that setter accumulated CO 2 ventilation program has positive effects and negative effects have not been identified yet.
In terms of post-hatch performance, differences between treatments were not found significantly different (p>0.05)except for the difference between chick weights and liveability (p<0.05).Liveability of young breeder flocks were lower in both the first week and slaughter.But, differences between CW values during the rearing period and BW and DWG values of treatment groups were found to be similar at the end of growing period.In addition, higher chick weight, BW and DWG values have been achieved in eggs of YC than YT.
These results were supported by data from Christensen et al. (1996) that liveability decreased with flock age and storage.Also, liveability data seems to be consistent with the data of (Bowling & Howarth, 1981;Elibol, 1997) who observed live weight differences in the first week and also closed up later in the rearing period.Similarly, data showing impairment in live weight are supported in terms of flock age (Christensen et al., 1996), but data suggesting deterioration in feed conversion ratios are supported (Hill, 2002).In contrast, unlike the incubation performance, in terms of growing performance, similar results were obtained from the study showing that raising CO 2 levels to a certain level or operating the CO 2 control system has negative effect on post-hatch performance (Taylor, 2000).
As a result, higher incubation and post-hatch performance were obtained from the eggs of young flocks stored for a short period.In addition, it was found that incubation and growing period performances of long time stored old flock eggs can be improved by incubating with accumulated CO 2 ventilation program.Thus, a more healthy and with higher quality chick production can be achieved and consequently production costs can be reduced and the competiveness of poultry companies can be improved.

Table 1 -
Trial design and used hatching eggs and broiler chick amounts in the study.
Flock Age Young (Y), 32 weeks age Old (O), 55 weeks age * YSC: Young flock, short storage time, control setter ventilation programme.YSN: Young flock, short storage tine, different (test) setter ventilation programme.YLC: Young flock, long storage time, control setter ventilation programme.YLT: Young flock, long storage time, different test setter ventilation programme.OSC: Old flock, short storage tine, control setter ventilation programme.OST: Old flock, short storage time, test setter ventilation programme.OLC: Old flock, long storage time, control setter ventilation programme.OLT: Old flock, long storage time, test setter ventilation programme.healthyday old chicks) were used in this study.Average hen housed egg productions and egg weights of

Table 2 -
Actualized temperature (°F), relative humidity (RH) and CO 2 (%) values in main days of incubation in the study.

Table 3 -
Raw material composition of feed used in the study

M Impacts of Breeder Age, Storage Time and Setter Ventilation Program on Incubation and Post-Hatch Performance of Broilers ROSS
® (2.0-2.5kgALW) recommendations (Ross

Table 4 -
The effect of different incubation practices on incubation performance.
abcd The difference between the averages indicated by different letters in the same column are statistically significant (p<0,05).Türkoğlu M

Table 5 -
The effect of different incubation practices on liveability.The difference between the averages indicated by different letters in the same column are statistically significant (p<0,05). abc

Türkoğlu M Impacts of Breeder Age, Storage Time and Setter Ventilation Program on Incubation and Post-Hatch Performance of Broilers Also
, it was found that interactions were significant (p<0.05) between breeder age-storage time and breeder age-setter ventilation program for post-hatch performance (Table6).Similarly, BW and DWG values were higher (p<0.05) in chicks obtained from the eggs of young flocks placed to setter operated with normal ventilation program (control treatment) than the test program (accumulated CO 2

Table 6 -
The effect of different incubation practices on post-hatch performance.The difference between the averages indicated by different letters in the same column are statistically significant (p<0,05). ab