Use of near infrared spectroscopy for intramuscular fat selection in rabbits

The potential use of near infrared spectroscopy (NIRS) for the determination of intramuscular fat (IMF) content in rabbit selection programmes was evaluated.  One hundred and thirty seven rabbits from three different synthetic lines slaughtered between 5 and 61 weeks of age were used for NIR calibration.  Longissimus muscles (LM) were homogenised, freeze-dried and scanned by NIRS reflectance and total lipid content was chemically analysed.  Calibration equation parameters reported appropriate results for IMF (cross-validation standard error, SECV=0.07g/100g muscle; cross-validation coefficient of determination, R2=0.98 and residual predictive deviation of cross-validation, RPD=7.57).  Another 88 rabbits were used to study the suitability of NIR spectroscopy in selection programmes.  Intramuscular fat was measured in LM using chemical and NIRS analyses.  Descriptive statistics showed that NIRS could be a proper technique to average comparison, but regression analyses (R2=0.92) and rank correlation measures, especially Kendall's tau-b correlation coefficient (0.83), indicated that NIRS may not be accurate enough to predict individual genetic values and produce ranking of animals.  However, NIRS technique could be applied in truncated selection where the efficiency of the method is measured by the response to selection.  Selection can be done on second parities using the IMF value of two full sibs of first parities.  Ten females and 5 males can be selected as parents to establish a new population of 40 females and 5 males.  The IMF values were similar between animals selected on the basis of chemically-determined IMF and NIRS-predicted IMF content.  Results of the experiment confirmed the potential of NIRS for the determination of IMF content in rabbit selection programmes instead of using laborious chemical methods