Effects of breeder age on embryonic development, hatching results, chick quality, and growing performance of the slow-growing genotype

Effects of in ovo vaccination time on broiler performance parameters under field conditions

Hatchery performance is often evaluated based on descriptors such as hatchability, 7-d mortality, and cost. In addition to these descriptors, it is useful to include in this analysis aspects of chick quality through post-hatch performance. Realizing the bird's complete genetic potential necessitates meeting various criteria, with effective support for the chick's immune system being among the pivotal factors. To be effective, in ovo vaccination systems must deliver the vaccines to specific sites in the egg, a circumstance that directly depends on when the injection is made. We examined production data to evaluate the impact of in ovo vaccination time on performance parameters of male Ross308AP chicks. A comprehensive survey was conducted examining records from 3,722 broiler flocks produced and raised by the same company under standard nutrition and management conditions. The selected data specifically pertained to flocks that underwent slaughter between 41 and 45 d. In our analysis, 4 different linear models were built, one for each response variable: mean weight (MW), body weight gain (BWG), corrected feeding conversion rate (cFCR), and total mortality (TM). The linear models used in the analyses included as main predictor the timing of in ovo vaccination (440, 444, 448, 452, 456, 458, and 460 h of incubation), and as additional predictors: age of the breeding flock (26-35, 36-55 and 56-66 wks old), slaughter age, identity of the hatchery, and the season at which the data was collected. Our results showed that the timing of in ovo vaccination significantly affected BWG and cFCR, with procedures performed at 460 h of incubation showing the best outcomes. Breeding flock age affected all response variables, with older breeding flocks delivering increased MW, BWG and TM, and middle-aged flocks increased cFCR. Increasing slaughter age reduced BWG while MW, cFCR and TM were all increased. These data emphasize the benefits of performing in ovo vaccination as close as possible to 460 h of incubation to extract the best BWG and cFCR from Ross308AP male broiler.

Breeder age and hatching egg storage duration: effects on post-hatch performance of FUNAAB- α broiler chickens

This trial was designed to evaluate the influence of hatching egg storage length and broiler breeder hens' age on post-hatch growth performance and physiological responses of FUNAAB-α chickens. Five hundred fertile eggs from each of 60 and 32-wk-old FUNAAB-α breeder hens were collected and assigned to five storage durations (0, 3, 7, 11, and 15 d). The hatching eggs were incubated using the conventional protocol. Data were collected on the growth performance and physiological responses. A 2 × 5 factorial design was used for the experiment. The results revealed that there was a decline in the final body weight in chickens from eggs of 15 and 11 d storage compared to the chickens from 7, 3, and 0 egg storage days. Chickens of 32-week-old breeder hens had higher (P < 0.05) mean corpuscular volume, white blood cell, heterophil, and pack cell volume values compared to 60-week-old breeder hens. Hatchlings from 60-week-old breeders had a higher liver percentage (3.0% yolk-free body weight [YFBW]) than those from 32-week-old breeders (2.8% YFBW). It was concluded that an extended storage duration of 15 d adversely affected the carcass traits and growth performance of chickens from egg storage above seven days.

Factors influencing the development of gastrointestinal tract and nutrient transporters' function during the embryonic life of chickens-A review

Intestinal morphology and regulation of nutrient transportation genes during the embryonic and early life of chicks influence their body weight and feed conversion ratio through the growing period. The intestine development can be monitored by measuring villus morphology and enzymatic activity and determining the expression of nutrient transporters genes. With the increasing importance of gut development and health in broiler production, considerable research has been directed towards factors affecting intestine development. Thus, this article reviews (1) intestinal development during embryogenesis, and (2) maternal factors, in ovo administration, and incubation conditions that influence intestinal development during embryogenesis. Conclusively, (1) chicks from heavier eggs may have a better-developed intestine than chicks from younger ones, (2) in ovo supplementation with amino acids, minerals, vitamins or a combination of several probiotics and prebiotics stimulates intestine development and increases the expression of intestine mucosal-related genes and (3) the long storage period, improper incubation temperature and imbalanced ventilation can negatively influence intestinal morphology and nutrient transporters gene expression. Finally, understanding the intestine development during embryonic life will enable us to enhance the productivity of broilers.

A Study on Egg Production and Quality According to the Age of Four Italian Chicken Dual-Purpose Purebred Hens Reared Outdoors

The month of hatching and the rearing management, especially temperature and photoperiod, are important factors for pullets and hens reared outdoors. The yield performance and egg quality of dual-purpose chicken breeds from the Veneto region (Italy), Pepoi (PP), Ermellinata di Rovigo (ER), Robusta Maculata (RM) and Robusta Lionata (RL), with different adult body weights (ABW, kg, PP = 1.3; ER = 2.3, RM and RL = 3.1), were studied, using a factorial model (4 × 2), considering breed and age (26-33 weeks, first age, summer-autumn, under decreasing natural photoperiod-on average, 12L:12D, and 42-53 weeks, second age, winter, under implemented photoperiod-14L:10D) as the main effects and interaction. The chicks hatched in spring, and they started laying at the end of summer/beginning of autumn. Significant (p < 0.05) results were shown for many traits. ER showed higher hen-day egg production than that of PP, and RM and RL were the lowest; ER, RM and RL showed medium-size eggs and PP showed small-size eggs. RM produced the most spherical eggs and ER the most ovoid, and they showed the highest and the lowest eggshell thickness, respectively. RM showed the highest yolk to albumen ratio, and RL showed the lowest. The age increased the laying rate and the egg weight in all the groups. At 26-33 weeks, ER and PP showed higher hen-day egg production (on average 24%) than RM and RL (on average, less than 10%). The onset of laying (at least 10% laying rate) was shown, at different ages, according to the % ABW the breeds had reached: PP was the first, followed by ER, then RM, and RL was the last. At 42-53 weeks, the hen-day egg production ranged, on average, from 38 to 52%, according to the breeds; orthogonal contrasts on two-weekly data showed, at first age, increasing linear (ER) and quadratic (other groups) trends, and at second age, positive linear (ER, RM) and cubic (PP, RL) trends. Age (32 vs. 53 weeks) affected almost all the eggshell traits in PP and ER, whereas in RL, and especially RM, fewer traits changed. The age increased the yolk to albumen ratio (unchanged in PP). These results may be useful for the effective management of local purebred chickens, with the purpose to ensure the wellbeing of the hens and for supplying eggs of different quality throughout the year.

Data Analytics of Broiler Growth Dynamics and Feed Conversion Ratio of Broilers Raised to 35 d under Commercial Tropical Conditions

Data collection is standard in commercial broiler production; however, growth modeling is still a challenge since this data often lacks an inflection point. This study evaluated body weight (BW) dynamics, feed intake, BW gain, feed conversion ratio (FCR), and mortality of broiler flocks reared under commercial tropical conditions with controlled feeding to optimize FCR. The data analyzed included performance records of 1347 male and 1353 female Ross 308 AP broiler flocks with a total of 95.4 million chickens housed from 2018 to 2020. Decision trees determined high- and low-feed-efficiency groups using FCR at 35 d. Logistic, Gompertz-Laird, and von Bertalanffy growth models were fitted with weekly BW data for each flock within performance groups. The logistic model indicated more accurate estimates with biological meaning. The high-efficiency males and females (p < 0.001) were offered less feed than the low-efficiency group and were consistently more efficient. In conclusion, greater feeding control between the second and the fourth week of age, followed by higher feed allowance during the last week, was associated with better feed efficiency at 35 d in males and females. Additionally, models demonstrated that a reduced growth rate resulted in heavier chickens at 35 d with better feed efficiency and greater BW gain.

Predicting hatchability of layer breeders and identifying effects of animal related and environmental factors

In this study, a data driven approach was used by applying linear regression and machine learning methods to understand animal related and environmental factors affecting hatchability. Data was obtained from a parent stock and grand-parent stock hatchery, including 1,737 batches of eggs incubated in the years 2010-2018. Animal related factors taken into consideration were strain (white vs. brown strain), breeder age, and egg weight uniformity at the start of incubation, whereas environmental factors considered were length of egg storage before incubation, egg weight loss during incubation and season. Effects of these factors on hatchability were analyzed with 3 different models: a linear regression (LR) model, a random forest (RF) model and a gradient boosting machine (GBM) model. In part one of the study, hatchability was predicted and the performance of the models in terms of coefficient of determination (R²) and root mean square error (RMSE) was compared. The ensemble machine learning models (RF: R² = 0.35, RMSE = 8.41; GBM: R² = 0.31, RMSE = 8.67) appeared to be superior than the LR model (R² = 0.27, RMSE = 8.92) as indicated by the higher R² and lower RMSE. In part 2 of the study, effects of these factors on hatchability were investigated more into detail. Hatchability was affected by strain, breeder age, egg weight uniformity, length of egg storage and season, but egg weight loss didn't have a significant effect on hatchability. Additionally, four 2-way interactions (breeder age × egg weight uniformity, breeder age × length of egg storage, breeder age × strain, season × strain) were significant on hatchability. It can be concluded that hatchability of parent stock and grand-parent stock layer breeders is affected by several animal related and environmental factors, but the size of the predicted effects varies between the methods used. In this study, 3 models were used to predict hatchability and to analyze effects of animal related and environmental factors on hatchability. This opens new horizons for future studies on hatchery data by taking the advantage of applying machine learning methods, that can fit complex datasets better than LR and applying statistical analysis.