Partial replacement of soybean meal with pea grains and sunflower cake in ewe diets: milk quality and blood biochemical parameters

ABSTRACT The objective of this research was to evaluate the effect of pea and sunflower cake as partial replacement for soybean meal in diet, as well as to assess their effect on milk quality during lactation and on blood parameters of ewes kept in organic farming. The research was carried out with 30 ewes of Merinolandschaf breed during 75 days. Ewes were given mixtures based on soybean meal as a protein source in control group (SBM), while in experimental groups, soybean meal was partially replaced with pea grain (P) and sunflower cake (SFC). Biochemical parameters (urea, glucose, total protein, albumin, globulins, cholesterol, HDL, LDL, triglyceride, β-hydroxybutyrate, and non-esterified fatty acids), as well as enzyme activity (ALT, AST, ALP, GGT, and CK) were determined in blood of ewes. Milk composition and concentration of fatty acids in milk fat were also determined. In comparison with control, sunflower cake as a protein source affected the increase of fat content in milk. When compared with pea grain and SBM, it decreased the urea concentration in milk. Oleic acid, total monounsaturated fatty acids, and n-6 increased, while saturated fatty acids, atherogenic, and thrombogenic indices decreased in SFC. Feeding ewes with peas increased the content of n-3 fatty acids in their milk. If compared to SFC, it also improved the n-6:n-3 ratio. Partial replacement of soybean meal with SFC reduced the blood concentration of total protein, globulin, and AST, and GGT enzyme activities and increased the β-hydroxybutyrate. Inclusion of pea grain and SFC can be adequately used as partial replacement of soybean meal in feeding of ewes kept in organic farming.