Sex and extruded linseed diet +/- concentrate in fiber effect on the fatty acid composition of pork
Résumé
The aim of this study is to compare the effect of diets containing extruded linseed +/- concentrate in fiber on the deposit of fatty acids in castrated and entire male pig’s tissues. Thirty six crossbreed castrated and entire growing-finishing male pigs (51 kg initial live weight, LW) received one of three experimental diets including a control diet (C), extruded linseed diet (EL) and EL poor fiber diet (EL-). Diets respectively contained 0.57, 3.90 and 4.35 g/kg of feed of ALA. Pigs were stunned at 115 kg LW and their backfat, adipose tissue of internal ham (ATH), liver and longissimus dorsi muscle were sampled to determine their fatty acids composition. Data was analysed by GLM procedure of SAS with the diet and the sex as main factor followed by a Bonferroni test. Results were expressed in g/100 g of total fatty acids (FA). There was less C18:2n-6 in the liver of castrated than in entire male pigs fed EL and EL- diets, in the backfat of pigs fed C and EL- diets and in ATH of pigs fed only with EL-. There was also a lower percentage of C18:3n-3 in the backfat and ATH of castrated compared to entire male pigs fed EL- and/or EL. The total of polyunsaturated fatty acids (PUFA), n-6 and n-3 FA were lower in the backfat of castrated than entire male pigs fed EL- diet. It was also the case for n-6 FA and n-3 FA in the backfat of castrated pigs fed the C and EL diet, respectively. The percentage of C18:3n-3 and total n-3 FA were lower in the muscle of castrated than entire male pigs fed the EL and EL- diets or EL- only, respectively. Regardless of the sex ALA deposition was statistically increased in the backfat and the muscle of pigs fed the EL- diet compared to the EL diet and castrated pigs had lower PUFA levels than entire male pigs, whatever the diet and the tissue.