Requirement for maintenance and gain of crude protein for two genotypes of growing quails

Abstract

-The objective of this study was to estimate the requirements for maintenance and gain of crude protein in Japanese and European quails aged 16-36 days. To determine the maintenance requirements, one experiment was conducted in a completely randomized design with four decreasing feeding levels (100, 75, 50 and 25%) and four replicates per treatment. The method of comparative slaughter was used, through a feeding assay. A total of 352 quails from each strain were housed by supply level in 16 pens measuring 1.0 × 1.5 m, totaling 22 birds per cage under ambient temperature conditions (26±0.5 °C). To estimate the requirement gains, one experiment was conducted with five groups of quails fed ad libitum and housed under controlled temperature of 18 °C. All poultry were slaughtered at 16, 21, 26, 31 and 36 days of testing for determination of body composition in protein throughout growth. The requirement for maintenance of the Japanese quail differs from that obtained with the European quail. The protein was retained at the proportion of 32% for European quails and 25% for the Japanese quails. This difference in retention promoted estimate of 0.65 g/g gain in European quails and 0.84 g/g gain in Japanese quails. Quails should be fed diets formulated considering the requirement for protein of each genotype.

Models for predicting protein requirements for meat quail

“…This k determined by comparative slaughter was close to the 32% found by Jordão Filho et al. () for meat quail aged 16–36 days reared in floor cages and under the same technique. However, k in our study was lower than results reported for other birds; Albino, Fialho, Bellaver, Hara, and Paiva () worked with white‐egg layers from 42 to 63 days of age and found 55.61% using the comparative‐slaughter technique, and Longo et al.…”

“…The slope of the line signifies that for every unit of nitrogen consumed, the proportion of 0.3986 nitrogen is retained in the bird's body, and there is an N retention of 39.86%. This k determined by comparative slaughter was close to the 32% found by Jordão Filho et al (2012) for meat quail aged 16-36 days reared in floor cages and under the same technique. However, k in our study was lower than results reported for other birds; Albino, Fialho, Bellaver, Hara, and Paiva (1994) worked with white-egg layers from 42 to 63 days of age and found 55.61% using the comparative-slaughter technique, and Longo et al (2001) obtained 72% for broiler hens.…”

“…However, the CPg of 517.44 mg CP/g of weight determined for the 2nd growth stage (15–35 days) differed from the 843 mg CP/g mentioned by the above mentioned authors for Japanese quail aged 15–32 days, and also from the 650 mg CP/g obtained by Jordão Filho et al. () in quail from 16 to 32 days of age. These results may be attributed to physiological differences between meat and laying quail lines and also to the different protein use efficiencies employed in each of these studies.…”

“…() reported a Nm of 0.76 g N/kg 0.75 /day for Japanese quail aged 15–32 days, while Jordão Filho et al. () obtained an average requirement of 0.78 g N/kg 0.75 /day for meat quail from 16 to 36 days of age. In addition to these results, the Nm found in our experiment was higher than the 0.42 g N/kg 0.75 /day observed by Scott et al.…”

“…The k is low when compared with the k determined in the nitrogen‐balance trial (58.52%); however, it is the value considered to determine the gain requirements (Exp. 3), since it best represents the body nitrogen retention of birds (Sakomura et al., ) and has been considered in many studies determining the protein requirements by the factorial method (Albino et al., ; Filardi et al., ; Jordão Filho et al., ; Longo et al., ; Sakomura et al., ; Silva et al., ).…”