Partitioning the efficiency of utilization of amino acids in growing broilers: Multiple linear regression and multivariate approaches

Abstract

Determining the efficiency of amino acid (AA) utilization in growing animals is crucial to estimate their requirement accurately. In broiler chickens, the composition of AA in feather is different from feather-free body and the proportion of feathers will change along broiler’s growth, which may impact the efficiency of utilization on AA consumed. Therefore, in order to establish a method that predicts the efficiency of utilization for feather-free body and feather, two approaches were evaluated: a multiple linear regression and a multivariate analysis. Additionally, a new factorial model was proposed to predict AA requirements in broiler chickens. Data from 13 trials that evaluated the requirements for lysine (Lys), sulphur AA (SAA), threonine (Thr), and valine (Val) in male broilers were used for the analyses. Both methods of analysis were consistent in showing that the efficiency of utilization in feather-free body and feather were different. Using multiple linear regression, the values of efficiency of utilization estimated in feather-free body were 0.68, 0.72, 0.81, 0.79 (mg of amino acid deposited / mg of amino acid consumed above maintenance) and in feather were 0.58, 0.77, 0.78, and 1.57 (mg/mg) for Lys, SAA, Thr, and Val, respectively. Applying the multivariate approach, the corresponding predicted values were 0.68, 0.67, 4.23, 0.27 (mg/mg) in feather-free body and 1.16, 0.86, 0.16, and 1.10 (mg/mg) in feather, respectively. According to the results, efficiency of utilization may be related, to some extent, on the concentration determined in each tissue. The uncertainty around the amount of AA consumed for gain directed to feather-free body or feather deposition could be a limitation for multivariate analyses. The results indicated that multiple linear regression predictions may be better estimates of utilization efficiency. However, more studies are needed to elucidate the effect of age on deposition and partitioning of dietary AA in different parts of the broiler.

Factorial models to estimate isoleucine requirements for broilers

“…In this study, the Iaa g was split into deposition in Bff and feather to determine EU, by multiple linear regression. Using a similar approach of Reis et al (), the Iaa g (dependent variable) was regressed against the amino acid deposited in Bff and feathers (independent variable) to determine the reciprocal of the regression coefficient, in other words, the efficiency of utilization for Bff and feathers. The values estimated herein were 0.69 and 0.53 for Bff and feather, respectively, which still closely related with what was found for the whole body.…”

“…Kielanowski () determined the EU of energy deposited as fat and protein, considering the deposition of each chemical component and the intake of energy above maintenance. The protein composition of feather‐free body and feathers are different (Fisher, Leeson, Morrison, & Summers, ; Stilborn, Moran, Gous, & Harrison, ), being reasonable to determine EU separately, as done by Reis, Sakomura, Teixeira, Silva, and Kebreab (). In some literature, factorial models to determine amino acid requirements utilize the same efficiency for feather‐free body (Bff) and feathers (Rostagno et al, ).…”

Developments in Rapid Detection Methods for the Detection of Foodborne Campylobacter in the United States

“…2011; Floch et al., 2012; Couturier et al., 2013; Gharst et al., 2013). This lack of sensitivity may result in some evidence suggesting that for poultry samples, qPCR assays may be more sensitive than a commercial enzyme-linked fluorescent assay when tested on chilled and frozen broiler carcasses (Reis et al., 2018).…”

“…No false negative results were detected and 100% of the Campylobacter positive samples were confirmed. Likewise, when Reis et al. (2018) compared qPCR Campylobacter with an immunoassay and conventional PCR on frozen and chilled broiler carcasses, the qPCR results were more sensitive.…”

Alternative procedure for determining lysine maintenance requirement in poultry

“…However, this procedure has been questioned because the deprivation of nitrogen or protein intake enhances the catabolism of body protein (Mitchell, 1924), and this physiological state does not correspond to practical farm conditions (Silva et al, 2014). Most maintenance requirements used in factorial models are assumed to vary with body weight or metabolic body weight (Lima et al, 2016;Reis et al, 2018;Silva et al, 2019;Melaré et al, 2019). However, it has been suggested that amino acid and protein requirements for maintenance are better related to body protein content (Emmans and Fisher, 1986;Siqueira et al, 2011;Lima et al, 2016).…”