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We aimed to estimate the non-phytate phosphorus (NPP) requirements of Chinese Jing Tint 6 layer chicks. We randomly allocated 720 birds to five treatments with six cages of 24 birds each, feeding them a corn-soybean diet containing 0.36%, 0.41%, 0.46%, 0.51%, and 0.56% NNP. The results showed that the body weight gain (BWG), tibial length, and apparent total tract digestibility coefficients (ATTDC) of P were affected (p < 0.05) by dietary NPP level. A quadratic broken-line analysis (p < 0.05) of BWG indicated that the optimal NPP for birds aged 1-14 d was 0.411%. Similarly, 0.409% of NPP met tibial growth needs. However, 0.394% of NPP was optimal for P utilization according to the ATTDC criterion. For 15-42 d birds, 0.466% NPP, as estimated by the BWG criterion, was sufficient for optimal growth without decreasing P utilization. Using the factorial method, NPP requirements were calculated as 0.367% and 0.439%, based on the maintenance factors and BWG for 1-14 and 15-42 d birds, respectively, to maintain normal growth. Combining the non-linear model with the factorial method, this study recommends dietary NPP levels of 0.367% and 0.439% for 1-14 and 15-42 d birds, respectively, to optimize P utilization without affecting performance.
RESUMEN
BACKGROUND: This study aims to determine the candidate markers that can be used as DNA barcode in the Lauraceae family. MATERIAL AND METHODS: Polymerase chain reaction amplification, sequencing efficiency, differential intra- and interspecific divergences, DNA barcoding gap, and identification efficiency were used to evaluate the four different DNA sequences of psbA-trnH, matK, rbcL, and ITS2. We tested the discrimination ability of psbA-trnH in 68 plant samples belonging to 42 species from 11 distinct genera and found that the rate of successful identification with the psbA-trnH was 82.4% at the species level. However, the correct identification of matK and rbcL were only 30.9% and 25.0%, respectively, using BLAST1. The PCR amplification efficiency of the ITS2 region was poor; thus, ITS2 was not included in subsequent experiments. To verify the capacity of the identification of psbA-trnH in more samples, 175 samples belonging to 117 species from the experimental data and from the GenBank database of the Lauraceae family were tested. RESULTS: Using the BLAST1 method, the identification efficiency were 84.0% and 92.3% at the species and genus level, respectively. CONCLUSION: Therefore, psbA-trnH is confirmed as a useful marker for differentiating closely related species within Lauraceae.