Determination of Eggshell Translucency as a Novel Non-invasive Predictive Tool for the Hatch of Fertile Eggs in Broiler Breeders

      

This study aims to evaluate shell translucency as a novel eggshell quality parameter to predict hatchability of fertile eggs. A total of 22,140 eggs were collected from 738 broiler breeder flocks between 25 to 65 wks of age, from multiple commercial hatcheries in the US. Translucency was completed with Zinpro® BlueBox^TM using a 3-point score system: TS1 = none or few small translucent spots; TS2 = several small translucent spots; TS3 = many large translucent spots. All eggs were individually evaluated for shell coloration lightness (L), thickness (Th), breaking strength (BS), translucency score percentage (TS1, TS2, TS3), and total translucency score (TS, the sum of the product of score and percentage). Pearson’s correlation was calculated using the rcorr function in the Hmisc library in R. Significance level was set at P< 0.05. Pearson’s correlation showed that HOF is negatively correlated with age (r=-0.45, P< 0.05), L (r=-0.25, P< 0.05) and Th (r=-0.08, P> 0.05), while a positive correlation was observed with BS (r=0.15, P< 0.05). To assess the effect of age and blocking its effect on HOF, a linear regression model with both linear and quadratic terms was completed with lm function in R, revealing that HOF peaked at 90.5% when breeders were 37-38 wks old. Shell quality parameters were individually regressed against HOF using age as a co-variable. Results from the fitted models showed that Th is quadratically (P< 0.05, R²=0.760) correlated with HOF, lowest at 0.418mm, and L showed a quadratic correlation (P< 0.05, R²=0.769) with HOF, peaking at 75%. However, BS showed no significant correlation with HOF (P< 0.05, R²=0.750). The TS1 showed positive linear (P< 0.05, R²=0.764) correlations with HOF, while TS3 was negatively correlated with HOF (P< 0.05, R²=0.764). Moreover, the total TS score exhibited a negative linear correlation with HOF (P< 0.05, R²=0.755). Results from translucency related parameters indicated a less TS1 or more TS3 score in eggs is correlated with a lower HOF. In summary, eggshell coloration lightness, thickness and translucency scores can be used as indicators of HOF. In conclusion, TS1 and TS displayed straightforward linear correlations with HOF, showing that translucency can be used as a novel eggshell quality parameter to predict HOF.

Key Words: Translucency, Eggshell quality, Hatch of fertile, Breeder, Hatchery.