Effects of increasing amount of dietary Prosopis laevigata pods on performance, meat quality and fatty acid profile in growing lambs

Abstract

A study with finishing lambs assessed the effect of dietary inclusion of Prosopis laevigata pods (PLPs) on performance, carcass characteristics, meat traits and fatty acid profile of subcutaneous fat. Twenty-one Rambouillet lambs (27.0 ± 3.0 kg BW) were assigned to one of three experimental diets with 0, 150 and 300 g PLP/kg DM. Evaluation of growth performance lasted 49 days. The experimental design was completely randomized and analysed with a mixed model. Lambs fed diets with 0, 150 and 300 g PLP had similar growth performance. Lambs fed diets with 300 g PLP/kg DM had better (p < 0.05) carcass yield and classification, less (p < 0.05) fat deposition and lower lightness (L*) value (p < 0.05) in meat than lambs fed diets with 0 and 150 g PLP/kg DM. Saturated fatty acids (palmitic and stearic) decreased (p < 0.05) and unsaturated fatty acids (oleic and linoleic) increased (p < 0.05) in subcutaneous fat of lambs fed diets with 150 and 300 g pods as compared with lambs not fed PLP. Prosopis laevigata pods are a safe feedstuff that can replace a third of conventional ingredients and reduce feed costs in growing lambs. Addition of PLP reduced (p < 0.05) total feed cost by 21%.

Effects of Prosopis laevigata pods on carcass characteristics, non-carcass components, meat quality, fatty acid profile and sensory attributes

“…Conformation and fat scores were influenced by treatments with PLP. Similarly, Negrete et al (2016) found that lambs fed 300 g PLP/kg had better conformation than lambs not fed PLP. Mesquite in diets decreased the acetate : propionate ratio in the rumen, owing to increases in propionate (Peña-Avelino et al, 2016), which is a precursor of glucose, the main carbon source for deposition of fat tissue.…”

“…The indicators of colour values (L, a and b) in lambs fed PL were different from those reported by Obeidat et al (2008) in sheep fed a 200 g/kg Prosopis juliflora diet. This may be related to low levels of secondary compounds such as tannins, which produce lighter-coloured meat, as found by Negrete et al (2016). The differences in coloration between the control diet and PL treatments can be associated with ultimate pH.…”

“…Recently, Negrete et al (2016) observed in finishing lambs that addition of 300 g PL pods per kg DM improved carcass yield and classification and shrinkage loss. The reduction of shrinkage loss by mesquite pods could be related with the improvement of fat score.…”

“…It may be explained by the fatty acid profile of mesquite pods. Indeed, Negrete et al (2016) indicated that C16:0, C18:0, C18:1 and C18:2 account for more than 90% of total FA, indicating that mesquite pods have 1.6-fold more C16:0, 4.3-fold more C18:0, 0.3-fold less C18:1 and 0.4-fold less C18:2 than maize grain, which was the conventional grain that was replaced in greater proportion when mesquite pods were included in the experimental diets. The ratio PUFA n6/n3 did not differ among treatments.…”

“…Most of these studies have shown that mesquite pods could replace conventional feeds without causing health problems or affecting growth performance in lambs. In a preliminary study, mesquite (P. laevigata) pods replaced a third of conventional ingredients (grain, by-products or forage) in finishing lamb diets with no effect on growth performance (Negrete et al, 2016). On the contrary, the addition of 300 g pods/kg DM reduced feed costs by 21%, and improved carcass yield and proportion of UFA in subcutaneous fat.…”