Zinc requirements of broiler breeder hens

The effect of phytase and inorganic Zn supplementation was studied in 180 male White Pekin ducks (WPD) from 1 to 56 days of age. The birds were divided into four groups fed the same basal diet (containing 26 ppm of Zn from raw materials): the control group did not receive Zn supplementation; the second group was supplemented with 30 ppm of Zn oxide; and the third and fourth groups were fed the control and the 30 ppm diets, respectively, both supplemented with 500 U of E. coli phytase. Each group contained five replicates of nine ducks. The body weight and feed intake were recorded at 1, 28 and 56 days of age. At 56 days of age, five birds/group were used to measure feed digestibility and five other birds/group were slaughtered. Zn at 30 ppm increased the body weight gain (BWG, p < 0.01) and feed intake (p < 0.05) and improved the feed conversion (FCR, p < 0.05) of the growing ducks. The Zn retention and Zn level in the excreta increased (p < 0.01) due to Zn supplementation. The addition of phytase improved BWG (p < 0.01) and FCR (p < 0.05) of growing ducks. The use of phytase reduced (p < 0.01) the level of Zn in duck excreta. Phytase supplementation to the basal diet at 30 ppm seems to be adequate to meet Zn requirements for ducks without further Zn additions.

Section: Introductionmentioning

confidence: 99%

“…Thus, the European Commission has recently established a maximum limit for the total Zn content, including the supplemental premix, of poultry diets at 100 ppm [11]. Therefore, the knowledge of the specific Zn requirements can reduce its supplementation in poultry diets, without affecting animal health, welfare and productivity [2].…”

Section: Introductionmentioning

confidence: 99%

Effects of Phytase Supplementation to Diets with or without Zinc Addition on Growth Performance and Zinc Utilization of White Pekin Ducks

Attia

Addeo

Al-Hamid

et al. 2019

“…The results of previous studies have indicated that Zn supplementation is important for enhancing the antioxidant capacity and improving the productive and reproductive performance [4,5,6,7], egg quality [8,9,10], and tibial quality [11,12,13] in laying hens and laying breeders. Reproductive performance, egg quality, tibial quality, antioxidant status, and tissue deposition are common variables employed in estimating the optimal dietary nutrient requirements for laying hens and breeders, following nonlinear regression models [6,14].…”

Section: Introductionmentioning

confidence: 99%

“…Zn requirement of Chinese yellow-feathered laying hens was 72 mg/kg diet, as indicated by Feeding Standard of Chicken [16], but these data were formulated more than 15 years ago and likely do not meet the actual needs of the modern strain of such birds, which has been subjected to a program of genetic improvement to meet the aspirations of poultry production industry. Additionally, the previous research on Zn requirements of laying hens was conducted in white-egg laying hens, which differ than those of the Chinese yellow-feather chicken breeders [6,14]. The aim of this study, therefore, was to estimate the dietary Zn requirements for optimal productive and reproductive performance, egg quality, tibial quality, yolk Zn deposition, and antioxidant status of Chinese yellow broiler breeder hens.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Dietary Zinc Requirement for Broiler Breeder Hens of Chinese Yellow-Feathered Chicken

Abouelezz

Gou

et al. 2019

This study aimed to establish the optimal dietary zinc requirement of Chinese yellow-feathered Lingnan broiler breeders. A total of 576 breeder hens aged 58 weeks were randomly assigned to six treatments, each with 6 replicates of 16 birds (n = 96/treatment). The hens were fed either a basal diet (22.81 mg/kg Zn) or the same basal diet supplemented with additional 24, 48, 72, 96, and 120 mg Zn/kg up to 65 weeks of age. Compared to the results of birds fed the basal diet (22.81 mg Zn/kg), the dietary supplementation with additional Zn (mg/kg) showed higher egg laying rate (at 48–120 mg), EM (at 96 mg/kg), yolk Zn content (at 24–120 mg/kg), fertility (at 48–120 mg/kg), hatchability (at 48–96 mg/kg), tibial breaking strength (at 24–48 mg/kg), tibial ash content (at 48 mg/kg), serum CuZnSOD activity (at 72 mg/kg) and T-AOC (at 48 mg/kg), and ovarian CuZnSOD and GSH-Px activities (at 96–120 mg/kg), and lower FCR (at 96 mg/kg). The regression model showed that the optimal supplemental Zn for maximal egg laying rate, yolk Zn content, fertility, and hatchability of Chinese yellow-feathered broiler breeders aged 58 to 65 weeks were 71.09, 92.34, 94.44 and 98.65 mg/kg diet, respectively.

“…where a = relative response to the diet containing the lowest Met (deficient diet); b = difference between the minimum and the maximum response obtained with dietary Met; c = curve slope coefficient; d = Met level of the deficient diet). The optimal Met was defined as Met = (-ln (0.05)/c) + d, using 95% of the asymptotic response, since the exponential curve never reaches the asymptotic point [18][19][20]. The suitability of the different models was evaluated by the correlation coefficient (R 2 ), Akaike information criteria (AIC) and mean square error values (MSE).…”

Section: Discussionmentioning

confidence: 99%

Modelling Methionine Requirements of Fast- and Slow-Growing Chinese Yellow-Feathered Chickens during the Starter Phase

Abouelezz

Cheng

et al. 2020

Two experiments were carried out to investigate the dietary methionine requirement for fast and slow-growing Chinese yellow-feathered breeds during the starter phase, based on growth variables and regression models. In Experiment 1, a total of 2880 one-day-old Lingnan chicks (fast growing breed) were used to test the methionine requirement from 1 to 21 days of age for males and females separately. Of each gender, 1440 birds were allocated into 6 dietary methionine levels (0.28%, 0.32%, 0.37%, 0.43%, 0.50% and 0.63%), each with 6 pen replicates of 40 chicks. Experiment 2 had the same design with Guangxi chicks (slow growing breed) from 1 to 30 d of age. Results indicated that significant nonlinear or quadratic responses to increasing dietary methionine levels were observed in body weight, daily gain, feed intake and feed conversion ratio of both breeds. In summary, the quadratic polynomial regression showed that the optimal methionine requirements for maximal growth performance of Lingnan chickens were 0.52–0.58% in males, 0.51% in females, and 0.53% in mixed genders. The corresponding values for Guangxi breed were 0.53% in males by quadratic polynomial regression and 0.43% in females, and 0.48% to 0.49% in mixed sexes by exponential asymptotic models.