NIRS of body and tissues in growing rabbits fed diets with different fat sources and supplemented with Curcuma longa

Abstract

[EN] A portable Near Infrared Reflectance Spectroscopy (NIRS) instrument was applied to 40 growing rabbits to determine body and tissue differences induced by experimental factors. The rabbits were examined at 2 live sites, in 7 warm carcass tissues and in longissimus dorsi muscle samples prepared in ethanol. For this purpose, the method was applied in a bi-factorial experiment concerning the dietary oil source (O) (maize vs. palm oil) and Curcuma longa (C) supplementation (0 and 3 g/kg, respectively). Significant chemical differences emerged for palmitic, oleic and linoleic acids in the longissimus dorsi muscle due to the O factor and for linolenic acid due to the C factor. The NIRS spectra and chemical analyses were elaborated by the Partial Least Squares (PLS) method, and the rsquares in cross-validation (R2cv) were retained as measure of the unoriented differentiation between the levels of the planned factor for each landmark and fatty acid (FA) profile. Multivariate PLS analysis of the FA muscular fat showed that the O factor induced strong differentiation (R2cv: 0.96), while less influence (0.33) was observed for the C factor. The model based on the NIRS radiation of the landmarks clearly shows the O factor effects, not only in the perirenal (0.90) and scapular (0.85) fats, but also in the belly (0.76), liver (0.73) and hind legs (0.72). Whereas the C effects were only expressed in the live animals (ears: 0.66 and abdominal wall: 0.58) and in post-mortem (liver: 0.60). It was concluded that a preliminary NIRS scan of the carcass and of live rabbits can point out the presence of intrinsic experimental effects concerning the lipid metabolism of polyunsaturated FA of the n-6 series (O factor) and n-3 series (C factor).