Relationship between fatty acid composition and softness score of adipose tissue in intensively reared lambs fed with concentrate based on cereals or on beet pulp

Abstract

-The aim of the study was to investigate the effect of substituting cereals by sugar beet pulp in the feed on the fatty acid (FA) composition of subcutaneous adipose tissue in indoor lambs. Forty-nine male lambs of the Lacaune dairy breed were fed from 23.6 (± 4.1) to 41.0 (± 1.9) kg live weight with hay and a pelleted concentrate containing either 80% of barley and wheat (group C) or 70% sugar beet pulp (group P). The FA composition of caudal adipose tissue sampled at slaughter was determined. The subcutaneous adipose tissue softness was not different between the two groups. The water content and the proportion of odd-numbered (oddFA) and methyl branched-chain FA (BCFA) were high but not significantly different between the two groups (respectively, 22.6% of wet weight, 7.7 and 9.7% of total FA). On the contrary, the proportion of even-numbered saturated FA (ESFA) and especially C 18:0 was low but slightly higher in the P group. The proportions of C 18:2 and C 18:3 were higher in group C than in group P (3.2 vs. 2.2%, P < 0.001 and 0.65 vs. 0.48%, P < 0.001, respectively). The softness score of adipose tissue was positively related to the water content and proportion of oddFA and BCFA. It was negatively related to the proportion of ESFA, age and live weight at the beginning of the trial. The proportion of unsaturated FA with 18 atoms of carbon did not show any relationship with the adipose tissue softness but it was influenced to some extent by the composition of the diet. lamb / sugar beet pulp / adipose tissue / fatty acid / softness index Résumé -Effet de la nature de l'énergie ingérée, céréales vs. pulpes de betteraves, sur la composition en acides gras du tissu adipeux caudal d'agneaux de bergerie. L'objectif de ce travail était de mesurer l'incidence de la distribution de pulpes de betteraves en remplacement des graines de céréales dans le régime alimentaire d'agneaux de bergerie sur la composition en acides gras (AG) du tissu adipeux de couverture. Au total, 49 agneaux mâles, de race Lacaune « lait » ont été engraissés de 23,6 (± 4,1) à 41,0 (± 1,9) kg. Ils disposaient en libre accès de foin et d'un aliment concentré aggloméré composé de 80 % d'orge et de blé (lot C) ou de 70 % de pulpe de betterave (lot P). La composition en AG d'un échantillon de tissu adipeux caudal prélevé sur chaque animal lors de l'abattage a été déterminée. L'index de fermeté ne diffère pas significativement entre les 2 groupes. La teneur en eau et la proportion des AG à chaîne carbonée impaire ou ramifiée ont été élevées et non significativement différentes (respectivement, 22,6 % du poids frais, 7,7 et 9,7 % des AG totaux). Inversement, les teneurs en AG saturés pairs et notamment en C 18:0 ont été faibles. Les teneurs en C 18:2 et C 18:3 ont été plus élevées dans le lot C que dans le lot P (3,2 vs. 2,2 %, P < 0,001 et 0,65 vs. 0,48 %, P < 0,001, respectivement). La note de fermeté des gras est liée positivement aux teneurs en eau et en AG à chaîne carbonée impaire ou ramifiée et négativement aux teneurs en AG gras satur...

Effects of extruded linseed on muscle physicochemical characteristics and fatty acid composition of lambs

“…There was also an absence of effect of linseed on colour parameters; this result is in agreement with those of some studies (Dumont et al 1997;Normand et al 2005) and in disagreement with some others (Ponnampalam et al 2002;Demirel et al 2004). The latter noted that meat with more unsaturated FAs is more susceptible to oxidation, resulting in a colour modification.…”

“…In fact, all concentrates have similar energetic and nitrogenous values. The lack of effect of linseed supplementation on lamb's growth was shown in other studies (Demirel et al 2004;Normand et al 2005;Bas et al 2007). …”

The effect of maternal linseed supplementation and/or lamb linseed supplementation on muscle and subcutaneous adipose tissue fatty acid composition of indoor lambs

“…As ALA proportion had a loading score orthogonal to the PC1 axis, it confirmed that, even when lambs were fed diets rich in ALA, softer and more colored AT was directly related to high proportions of Odd-FA and OBCFA and to lower proportions of even-saturated FA. This has already been observed in lambs fed high concentrate diets (Bas, Giral, & Rouzeau, 1998;Miller, Kunsman, & Field, 1980;Normand et al, 2005;Orskov, Duncan, & Carnie, 1975).…”

“…All GC procedures are described in Berthelot et al (2010). Methyl branched chain FA were identified from length equivalent chains (LEC, Miwa, Mikolajzack, Earle, & Wolff, 1960) by interpolation between two consecutive saturated FA and compared to methyl ester standard mixtures (Sigma, St. Louis, MO) injected the same way for iso and anteiso-FA and FA previously identified by electron impact mass spectrometry for other methylbranched chain FA (OBCFA, Berthelot, Bas, Schmidely, & Duvaux-Ponter, 2001;Berthelot, Normand, Bas, & Kristensen, 2001;Normand, Bas, Berthelot, & Sauvant, 2005). Proportions of C18:1 isomers separated on the CP-SIL column were determined in relation with the proportion of the C18:0 obtained on the DB-wax column.…”