Effects of amino acid levels during rearing on Cobb 500 slow-feathering broiler breeders: 2. Reproductive performance

Abstract

Crude protein and amino acid ( AA ) content in rearing diets affect body composition and reproductive performance. This study evaluated the effects of 4 dietary AA levels during rearing on BW, egg production and composition, fertility, hatchability, and embryo mortality up to 65 wk of age on Cobb 500 slow-feathering ( SF ) broiler breeders. The treatments consisted in 80% (low-AA), 90% (moderate-AA), 100% (standard-AA), and 110% (high-AA) of the AA recommendations for Cobb 500 SF pullets from 5 to 24 wk. AA was guided by an ideal protein profile based on digestible Lys. A total of 1,360 pullets and 288 Cobb MV cockerels were randomly placed in 16 pullets and 16 cockerel floor-pens. At 22 wk, 1,040 females and 112 males were transferred into 16-floor pens in a laying house. BW increased linearly ( P < 0.01) as AA augmented at 25, 36, and 40 wk. No effects ( P > 0.05) at the onset of lay were observed. Moderate-AA and standard-AA resulted in the best hen-housed egg production ( HHEP ) at 65 wk with 174.3 and 176.5 eggs, respectively. The optimum level of AA for HHEP at 65 wk was estimated ( P < 0.001) in 96.7% and 94.7% by the quadratic and broken line models, respectively. Overall, the lightest egg weight ( P = 0.022) was obtained with 89%AA during rearing, and the heaviest eggs ( P < 0.001) were found at 54 wk. Response surface regression indicated linear effects on albumen and yolk percentages ( P < 0.01) increasing and decreasing, respectively, as AA levels augmented; consequently, AA had a negative linear effect on Y:A ratio ( P = 0.004) with quadratic effects ( P < 0.01) of age (R 2 = 0.92). No statistical effect of treatments was observed in fertility ( P > 0.05), but AA had a quadratic effect ( P = 0.046) on hatchability up to 50 wk of age with 97% as optimum, and decreased linearly ( P = 0.004) from 51 to 65 wk. A few effects of treatments ( P < 0.05) on embryo mortality were observed. In conclusion, AA levels during rearing affect broiler breeder reproductive performance.

In pursuit of a better broiler: welfare and productivity of slower-growing broiler breeders during lay

“…Overall, high and persistent laying rate led to high cumulative egg production in strain A and strain B by the end of the study (above 165 eggs/hen on average). Compared to previous research, the strains in our study had higher cumulative egg production than conventional broiler breeders (e.g., Ross 308: 143 eggs/hen [ Arrazola et al., 2019b ; Aviagen, 2021a], Ross 708: 137 eggs/hen [ van der Klein et al., 2018 , Aviagen, 2021b], and Cobb 500: 138 eggs/hen [ Arabinar et al., 2020 ; Oviedo-Rodon et al., 2021 ]). Previous research with alternative strains also concluded that slower growing strains of broiler breeders can achieve higher egg production than conventional feed-restricted broiler breeders ( Heck et al., 2004 ; Gebhardt-Henrich et al., 2018 ).…”

“…Hens started laying earlier than expected according to breeding guidelines, and laying rate peaked at different ages among the hen strains. After the peak, laying rate persisted at a high rate for two of the hen strains (A and B) whereas laying rate dropped below 50% in 2 pens of strain C. In conventional broiler breeder hens, laying rate drops linearly after peak as body weight increases (e.g., Ross 308 [ van Emous et al., 2015a ; Arrazola et al., 2019b ], Ross 708 [van der Klein et al., 2018] , and Cobb 500 [ Arabinar et al., 2020 ; Oviedo-Rodon et al., 2021 ]). Certainly, fast growth rate and excessive fat accumulation negatively impact the reproductive performance and health of broiler breeders, and the severity of obesity-related problems depends on individual and strain susceptibility to lipotoxicity ( Heck et al., 2004 ; Chen et al, 2006 ; Renema et al., 2007 ; Walzem and Chen, 2014 ).…”

“…During lay, performance objectives for slower growing broiler breeders indicate that they can achieve high reproductive performance (e.g., high and persistent laying rate at a high hatchability) at a lower level of feed restriction level ( Aviagen, 2018a ; Hubbard, 2019 ; Sasso 2019 ). In conventional broiler breeders, laying persistency decreases soon after hens reach the peak in egg production (e.g., Ross 308 [ van Emous et al., 2015a ; Arrazola et al., 2019b ], Ross 708 [van der Klein et al, 2018] , and Cobb 500 [ Arabinar et al., 2020 ; Oviedo-Rodon et al., 2021 ]), and hatchability decreases in settable eggs laid after 45 to 50 wk of age ( Igbal et al., 2016 ; Aviagen, 2021a , b ; Cobb, 2020 ). Hence, using slower growing broiler breeders may not only alleviate welfare concerns about chronic feed restriction but also lead to a more efficient and sustainable production system.…”

Functional properties of amino acids: improve health status and sustainability

“…Hens having larger breast meat may have more difficulties in exposing their cloaca for mating, which can lead to incomplete mating and decreased fertility ( Aviagen, 2018 ). In addition, hens provided with 110% lysine diets produced fewer eggs compared to when feeding according to recommendations during rear ( Oviedo-Rondon et al, 2021 ). Interestingly, feeding an 80% lysine diet also caused a slight reduction in egg production indicating the importance of feeding diets with balanced amino acids.…”

Bone quality and incidence of urolithiasis in male broiler breeders fed a male or female ration.

“…The quality and amino acid balance in protein diets is essential for growth and reproduction performance (Oviedo-Rondón et al, 2021).…”