Effects of dietary pomegranate seed cake supplementation on performance, carcass characteristics and meat quality of growing lambs

Abstract

The aim of the study was to evaluate the effects of dietary pomegranate seed cake (PSC) supplementation, in replacement of corn and barley grain, on productive traits, carcass characteristics, intramuscular and subcutaneous fatty acid (FA) composition and meat antioxidant status. For the experiment, which lasted for 63 days, thirty six male growing Florina (Pelagonia) lambs were used. Lambs with a mean body weight (BW) of 19.86 ± 2.78 kg, were randomly allocated into four dietary treatments (PSC0, PSC115, PSC175, and PSC235) of 9 lambs each and accommodated in individual floor pens. The PSC was added to the concentrate mixture at inclusion levels of 0, 115, 175, and 235 g/kg concentrate for treatments PSC0, PSC115, PSC175 and PSC235, respectively. No differences (P > 0.05) occurred among PSC treatments in final BW, BW gain, dry matter (DM) intake and feed conversion ratio. Moreover, carcass characteristics were not affected (P > 0.05), except for the lean and fat color, fat firmness, wetness and overall acceptability of carcasses that were quadraticaly improved, with increased PSC feeding. In both intramuscular and subcutaneous fat, proportions of trans C18:1 (P = 0.001; P < 0.05, respectively), C18:2n-6t (P = 0.001; P < 0.01, respectively), and cis-9, trans-11 C18:2 (P = 0.001; P < 0.05, respectively) were linearly increased and Δ9-desaturase activity index concerning C18:1/C18:0 was linearly decreased (P < 0.05; P < 0.01, respectively). Moreover, in subcutaneous fat trans-10, cis-12 C18:2 (P = 0.001), cis-9, trans-11, cis-13 C18:3 (punicic acid; P = 0.001) and polyunsaturated fatty acid (PUFA) (P < 0.05) proportions were linearly increased and that of cis-9 C18:1 (P < 0.05), C18:2n-6c (P = 0.001), C18:3n-3 (P = 0.001) and C20:3n-3 (P = 0.001) were linearly decreased with increasing PSC feeding. No effects (P < 0.05) of dietary PSC were observed in meat 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) values, but a linear increase (P = 0.001) was found in meat malondialdehyde (MDA) concentration, being higher only in PSC235 treatment relative to control. Higher oxygen radical absorbance capacity (ORAC) values were observed in the intramuscular fat of lambs fed with PSC175, but lower in PSC235 treatment. Thus, pomegranate seed cake could partially replace cereals in growing lambs diets with no effects on their performance and carcass quantitative characteristics. Moreover, dietary PSC supplementation could improve the nutritional and functional properties of meat and subcutaneous fat, as indicated by the increase in essential fatty acids, such as trans-10, cis-12 C18:2. Low inclusion levels of PSC could have a positive effect on antioxidant potential, and on nutritional and functional quality of meat, whereas high levels (i.e. 235 g/kg of concentrate) could posses an opposite effect.