Legume grain-based supplements in dairy sheep diet: Effects on milk yield, composition and fatty acid profile

Withtheaimto findproteinsourcesthatarefreeofgeneticallymodifiedorganisms,theeffectsoflegumegrain- based concentrates, used as alternatives of a mixed concentrate feed containing soybean, were evaluated on sheep milk production. Twelve lactating ewes were divided into four groups, fed hay and, according to a 4 · 4 Latin square design, suppliedwith800g/dayofacommercialmixedconcentratefeed(MCF)containingmaizeandsoybean,orthesameamount of isoprotein concentrates consisting of chickpea (CH), faba bean (FB), or pea (PE) mixed with barley. The ewes ingested more of the concentrates with legume grains than the MCF (702, 702, 678 vs 587 g/day DM for CH, FB, PE and MCF; P � 0.001). Compared with CH, FB and PE resulted in greater (P � 0.05) milk yield (710, 718vs 654g/day for FB, PE and CH,respectively), andledtoagreater (P � 0.05)efficiencyof dietaryproteinutilisation for milkcaseinsynthesis(94,97vs 87 g casein/kg crude protein intake for FB, PE and CH, respectively), whereas MCF resulted in intermediate levels of milk yield(677g/day)andmilkcasein/crudeproteinintake(88g/kg).Chickpeaincreasedthemilkcontentoftrans-vaccenicand rumenic acids in comparison with FB and PE and, similarly to MCF, increased the milk content of linoleic acid, as well as total unsaturated fatty acids (24.3, 23.9 vs 17.2, 16.8 g/100 g fatty acid methyl esters for MCF, CH, FB and PE;P � 0.001), thereby improving the potential health-promoting index. Legume grains can replace soybean in diets of dairy ewes, as they do not adversely affect milk yield and composition.