Exigências de lisina para codornas em crescimento : um estudo meta-analítico

Abstract

This research aimed to (1) structure a database about lysine (Lys) requirement for growing quails; (2) estimate the Lys requirement for weight gain in mg/g; (3) determine the efficiency of Lys utilization for growth; (4) parameterize a model to calculate Lys intake for growing quails and (5) integrate the quails growth curves into the model to enable the daily calculation of iLys. The proposed model considers the partition of Lys for maintenance and growth, according to the general equation: iLys = maintenance + growth, where iLys is the ingestion of Lys. Maintenance, maintenance Lys partition was calculated for each observation using the body weight (BW) value of each study included in the database. The maintenance constant used was 135.57 mg/kg BW. The partition for growth was obtained by difference, growth = iLys-Maintenance. The requirement for weight gain (kg) was obtained by the ratio between the partitioned Lys for growth and weight gain (BWG) of each observation contained in the database. The utilization efficiency was obtained considering the relationship between lysine deposition and ingestion. The variables iLys, BW and BWG were extracted from each publication. Initially, kg was considered as an independent constant BW. Additionally, the fit between kg and BW was considered as a linear, quadratic and exponential polynomial relationship and based on the fit statistics the models were selected. The growth of the body and feathers of different quail strains was described: Vicami, Fujikura and Estrela Gaúcha. To describe growth, the Gompertz function was used, which considers body weight at maturity (Pm, in g), body weight at birth (Pi, in g), maturity rate (B, per day), age (t, in days), the Euler number (e) and the natural log (ln). The database was composed by 135 information contained in 17 studies. Some of the published studies did not provide enough information to meet the pre-established criteria, making it impossible to use these data. The value found for kg was 32 mg/g of BWG. The efficiency of using Lys for quails in growth was calculated in 28.4%, when considering kg independent of BW. The linear, quadratic and exponential relationship between kg and BW did not improve the prediction error of iLys, being used the value of kg for all BW, according to the iLys model=135.57BW+32BWG, ±38. Based on the relationship between weight and age, the parameters of the Gompertz curve for body and feather growth were adjusted, with m the lines showing similar growth profiles. These values were applied to the selected model, making it dynamic and enabling the prediction of daily iLys.