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Evaluating the Age-Dependent Potential for Protein Deposition in Naked Neck Meat Type Chicken.

Khan DR, Wecke C, Sharifi AR, Liebert F - Animals (Basel) (2015)

Bottom Line: The introduction of the naked neck gene (Na) into modern meat type chicken is known to be helpful in increasing the tolerance for a high ambient temperature (AT) by reducing the feather coverage which allows for a higher level of heat dissipation compared to normally feathered (na/na) birds.In addition, reduced feather coverage could affect requirements for sulfur containing amino acids.The observed estimates depending on genotype, sex and age varied for NMR and NRmaxT from 224 to 395 and 2881 to 4049 mg N/BWkg(0.67)/day, respectively.

View Article: PubMed Central - PubMed

Affiliation: Division Animal Nutrition Physiology, Department of Animal Sciences, Georg-August-University, Kellnerweg 6, 37077 Goettingen, Germany. dkhan@gwdg.de.

ABSTRACT
The introduction of the naked neck gene (Na) into modern meat type chicken is known to be helpful in increasing the tolerance for a high ambient temperature (AT) by reducing the feather coverage which allows for a higher level of heat dissipation compared to normally feathered (na/na) birds. In addition, reduced feather coverage could affect requirements for sulfur containing amino acids. As a prerequisite for further modeling of individual amino acid requirements, the daily N maintenance requirement (NMR) and the threshold value of daily N retention (NRmaxT) were determined. This was carried out using graded dietary protein supply and exponential modeling between N intake (NI) and N excretion (NEX) or N deposition (ND), respectively. Studies with homozygous (Na/Na) and heterozygous (Na/na) naked neck meat type chicken utilized 144 birds of average weight (50% of each genotype and sex) within two N balance experiments during both the starter (days 10-20) and the grower period (days 25-35). Birds were randomly allotted to five diets with graded dietary protein supply but constant protein quality. The observed estimates depending on genotype, sex and age varied for NMR and NRmaxT from 224 to 395 and 2881 to 4049 mg N/BWkg(0.67)/day, respectively.

No MeSH data available.


Related in: MedlinePlus

Estimation of N maintenance (NMR) by fitting exponential function between daily N intake (NI) and daily N excretion (NEX) following graded protein supply depending on sex, genotype and age period. (a) Males; (b) Females.
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animals-05-00056-f001: Estimation of N maintenance (NMR) by fitting exponential function between daily N intake (NI) and daily N excretion (NEX) following graded protein supply depending on sex, genotype and age period. (a) Males; (b) Females.

Mentions: Results of the exponential fitting of NEX against NI provide a mathematical approach of the NEX at N free feeding level (Figure 1). The observed mean daily NMR for male (293 mg/BWkg0.67) and female chickens (380 mg/BWkg0.67) of genotypes under study are summarized in Table 6. These threshold values are higher than in previous studies with normally feathered counterparts (GRRS [15]: 264 mg/BWkg0.67; Samadi and Liebert [8]: 252 mg/BWkg0.67; Pastor et al. [11]: Starter 113, grower 215 mg/BWkg0.67).


Evaluating the Age-Dependent Potential for Protein Deposition in Naked Neck Meat Type Chicken.

Khan DR, Wecke C, Sharifi AR, Liebert F - Animals (Basel) (2015)

Estimation of N maintenance (NMR) by fitting exponential function between daily N intake (NI) and daily N excretion (NEX) following graded protein supply depending on sex, genotype and age period. (a) Males; (b) Females.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494337&req=5

animals-05-00056-f001: Estimation of N maintenance (NMR) by fitting exponential function between daily N intake (NI) and daily N excretion (NEX) following graded protein supply depending on sex, genotype and age period. (a) Males; (b) Females.
Mentions: Results of the exponential fitting of NEX against NI provide a mathematical approach of the NEX at N free feeding level (Figure 1). The observed mean daily NMR for male (293 mg/BWkg0.67) and female chickens (380 mg/BWkg0.67) of genotypes under study are summarized in Table 6. These threshold values are higher than in previous studies with normally feathered counterparts (GRRS [15]: 264 mg/BWkg0.67; Samadi and Liebert [8]: 252 mg/BWkg0.67; Pastor et al. [11]: Starter 113, grower 215 mg/BWkg0.67).

Bottom Line: The introduction of the naked neck gene (Na) into modern meat type chicken is known to be helpful in increasing the tolerance for a high ambient temperature (AT) by reducing the feather coverage which allows for a higher level of heat dissipation compared to normally feathered (na/na) birds.In addition, reduced feather coverage could affect requirements for sulfur containing amino acids.The observed estimates depending on genotype, sex and age varied for NMR and NRmaxT from 224 to 395 and 2881 to 4049 mg N/BWkg(0.67)/day, respectively.

View Article: PubMed Central - PubMed

Affiliation: Division Animal Nutrition Physiology, Department of Animal Sciences, Georg-August-University, Kellnerweg 6, 37077 Goettingen, Germany. dkhan@gwdg.de.

ABSTRACT
The introduction of the naked neck gene (Na) into modern meat type chicken is known to be helpful in increasing the tolerance for a high ambient temperature (AT) by reducing the feather coverage which allows for a higher level of heat dissipation compared to normally feathered (na/na) birds. In addition, reduced feather coverage could affect requirements for sulfur containing amino acids. As a prerequisite for further modeling of individual amino acid requirements, the daily N maintenance requirement (NMR) and the threshold value of daily N retention (NRmaxT) were determined. This was carried out using graded dietary protein supply and exponential modeling between N intake (NI) and N excretion (NEX) or N deposition (ND), respectively. Studies with homozygous (Na/Na) and heterozygous (Na/na) naked neck meat type chicken utilized 144 birds of average weight (50% of each genotype and sex) within two N balance experiments during both the starter (days 10-20) and the grower period (days 25-35). Birds were randomly allotted to five diets with graded dietary protein supply but constant protein quality. The observed estimates depending on genotype, sex and age varied for NMR and NRmaxT from 224 to 395 and 2881 to 4049 mg N/BWkg(0.67)/day, respectively.

No MeSH data available.


Related in: MedlinePlus