Akademik Veri Yönetim Sistemi
Avian and Poultry Biology Reviews, cilt.13, sa.4, ss.243-244, 2002 (SCI-Expanded)
It is well known that the egg storage period prior to incubation can influence hatchability, chick quality and hatching time. Therefore, these factors are of considerable concern in commercial hatchery practice. One practice that can diminish the negative effects of an extended storage period is pre-warming the eggs prior to incubation. The objective of the present study was to examine the interaction of length of storage period and pre-warming period after storage on hatchability of fertile eggs, embryonic mortality and hatching time of broiler hatching eggs. Hatching eggs were obtained from flocks of Ross male x Ross 308 female broiler breeders at 31 weeks of age. Eggs were stored for 1 or 14 days at 18°C and 75% RH. Three pre-warming periods were used after storage. These treatments were no pre-warming (0 hours), pre-warming for ten hours (10 hours), or pre-warming for 18 hours (18 hours). Pre-warming was done in an operating setter at 26°C and 70-75% relative humidity. Each incubation tray of 150 eggs constituted a replicate. There were a total of 12 trays in the experiment and each treatment group had two replicate trays. Eggs were transferred from the incubator to the hatching baskets at 19 days of incubation and hatching time was monitored at 486 hours (Early), 498 hours (Mid) and 510 hours (Late) of incubation. Chicks were deemed to be hatched when they exhibited healed navels and dryness about the head and neck. At the time of removing the chicks from the hatchers, all unhatched eggs were opened and examined macroscopically by a single experienced individual to determine percentage embryonic mortality (early (0 to 6 days), middle (7 to 17 days), late (18 to 21 days plus pipped)), and percentage hatchability of fertile and total eggs. Hatchability of fertile eggs was calculated as the number of chicks hatched per fertile egg set. The results for the incubation variables were analysed by ANOVA with the general linear model (GLM) procedure (SAS Institute, 1990). The results of hatch time were analysed by Z test for proportionality. As expected, eggs subjected to extended storage exhibited lower percentage fertile hatchability, increased embryonic mortality and second quality chicks (Table 1). Hatchability of fertile eggs was significantly lower when there was no pre-warming period compared to having a pre-warming period of 10 hours or 18 hours. This was due to an increase in percentage early dead embryos (Table 1). Table 2 shows the percentage of chicks hatched in each time period by storage and pre-warming treatments. Generally, hatching time was extended in eggs stored 14 days compared Table 1 The effect of storage and pre-warming periods on hatchability of fertile eggs and embryonic mortality (means ± SE) Pre-warming period (hours) Storage Period 0 10 18 Average Early dead (%) 1 4.42 ± 0.37 3.76 ± 1.04 3.05 ± 1.0 3.75 ± 0.46a 14 22.86 ± 2.31 11.87 ± 1.06 11.99 ± 3.77 15.6 ± 2.86b Average 13.64 ± 5.41a 7.8 ± 2.41b 7.5 ± 3.03b Late dead (%) 1 2.03 ± 0.67 2.39 ± 0.35 1.69 ± 0.34 2.04 ± 0.25a 14 8.53 ± 0.37 6.09 ± 1.34 5.13 ± 1.03 6.58 ± 0.78b Average 5.28 ± 1.90 4.24 ± 1.21 3.41 ± 1.09 2nd Quality Chicks (%) 1 0.68 ± 0.01 1.02 ± 1.03 0.67 ± 0.01 0.79 ± 0.28a 14 1.70 ± 0.34 2.03 ± 0.01 1.71 ± 0.34 1.81 ± 0.14b Average 1.19 ± 0.33 1.53 ± 0.51 1.19 ± 0.33 Hatchability of fertile eggs (%) 1 92.52 ± 0.63 92.14 ± 3.1 94.23 ± 1.04 92.96 ± 0.95a 14 64.52 ± 3.29 76.61 ± 0.42 78.42 ± 3.77 73.18 ± 3.05b Average 78.52 ± 8.20a 84.37 ± 4.66b 86.33 ± 4.83b a,b,c Means ± SE with different superscripts differ significantly (P < 0.05). Table 2 The effect of storage and pre-warming periods on chicks hatching time distribution (%) Storage period Hatch time* Pre-warming period (hours) 0 10 18 Early (%) 70.6ax1 63.7ax1 69.6ax1 1 Mid (%) 26.5bx1 30.4bx1 25.8bx1 Late (%) 2.9cx1 5.9cx1 4.6cx1 Early (%) 14.8ay2 25.7ax2 22.9ax2 14 Mid (%) 27.0by1 39.8bx1 41.9bx2 Late (%) 58.2cy2 34.5bx2 36.5bx2 *Early = hatch, up to 486 hours; Mid = hatch between 486-498 hours; Late = hatch between 498-510 hours. a,b,c Means in columns (same storage period with different pre-warming period) with different superscripts differ significantly (P < 0.05). 1,2Means in columns (same pre-warming period with different storage period) with different superscripts differ significantly (P < 0.05). x,yMeans in row with different superscripts differ significantly (P < 0.05). to 1 day (Table 2). Although hatching time was not affected by pre-warming period in eggs stored 1 day, different results were found for eggs stored 14 days. The results suggest that after an extended storage period, pre-warming of broiler hatching eggs increased the hatchability of fertile eggs and shortened hatching time earlier than expected for stored eggs in 14 days.