Does the Naked Neck Meat Type Chicken Yield Lower Methionine Requirement Data?

Abstract

Simple SummaryIt was hypothesized that naked neck chickens could have a lower methionine requirement according to their reduced feather coverage. The hypothesis was examined by nitrogen balance studies and non-linear model application for estimating methionine requirement data of naked neck chickens. It was concluded that naked neck birds do not require less methionine than normally-feathered birds.AbstractMethionine (Met) requirement studies with homozygous (Na/Na) and heterozygous (Na/na) naked neck meat type chicken utilized 144 birds of average weight (50% each genotype and sex) within two N balance experiments involving both the starter (d10–20) and grower period (d25–35). The birds were randomly allotted to five experimental diets with graded protein supply and Met as the limiting amino acid. The proportion of native feed protein sources (soy protein concentrate, maize, wheat, fishmeal and wheat gluten) was kept constant to ensure a uniform protein quality in all diets. The Met requirement depending on genotype, sex, age period and growth performance (protein deposition) was estimated using a non-linear modeling procedure of N utilization in monogastric animals. On average, 0.47% (Na/Na) and 0.45% (Na/na) dietary Met was established as adequate in the starter diet, as well as 0.37% (Na/Na) and 0.36% (Na/na) Met in the grower diet for both of the sexes. In conclusion, the Met requirement of the naked neck chicken is not significantly different from its normally-feathered counterparts. In addition, the low feather production was not reflected by reduced requirement for Met in naked neck birds. However, these conclusions are valid only at the given Met:Cys ratio (1:1) in the experimental diets.

N Balance Studies Emphasize the Superior Protein Quality of Pig Diets at High Inclusion Level of Algae Meal (Spirulina platensis) or Insect Meal (Hermetia illucens) when Adequate Amino Acid Supplementation Is Ensured

“…The genotype dependent model parameters for daily (piglets: 433 mgN/BW kg 0.67 ; pigs: 388 mgN/BW kg 0.67 ) and (piglets: 4697 mgN/BW kg 0.67 ; growing pigs: 3104 mgN/BW kg 0.67 ) were taken from earlier studies [ 28 , 29 ]. According to recent reports making use of the exponential model [ 6 , 7 , 21 , 22 , 23 , 24 , 26 , 30 , 31 , 32 , 33 , 34 , 35 ], the dietary protein quality was evaluated by parameter ( ) based on the equation: …”

Validation of the Lysine Requirement as Reference Amino Acid for Ideal In-Feed Amino Acid Ratios in Modern Fast Growing Meat-Type Chickens

“…Data analysis utilized current applications of an exponential N utilization model [10] Earlier reports [36]- [38] also validated the linear relationship between LAA concentration (c) in the feed protein and the response on dietary protein quality (model parameter b). In consequence, the quotient bc −1 defines the slope of the linear relationship and indicates the efficiency of the LAA in the diet [10] [33]. The term "efficiency" summarizes the AA utilization for NR in the body taking into account both digestion, absorption and post-absorptive AA utilization.…”