Effects of probiotic supplementation on milk production, blood metabolite profile and enzyme activities of ewes during lactation

There is scarce information regarding the effects of probiotics in the diet of lactating ewes on milk yield and composition as well as on metabolite concentrations and enzyme activities in blood. Sixteen Sanjabi ewes, kept under the same feeding and management practices, were divided in two equal groups. The ewes in the first group were fed a diet without probiotics, while the ewes of the second group were fed the same diet supplemented with two grams of commercial probiotics (PrimaLacVR 454 Feed grade, containing Lactobacillus acidophilus, 2.5107 CFU/g; Lactobacillus casei, 2.5107 CFU/g; Bifidobacterium thermophilum, 2.5107 CFU/g; Enterococcus faecium, 2.5107 CFU/g). Milk yield measurements, milk composition and blood plasma analyses were carried out at the fourth, eighth and twelfth week of lactation. Probiotics had no effects (p>.05) on any of the examined variables during the first two-thirds of lactation. In the last third of lactation, probiotic supplemented ewes showed an increase (p<.05) of aspartate aminotransferase activity in blood plasma (209 versus 98 U/L) as well as higher (p<.05) yields of milk (503 versus 312 g/d), fat (34.8 versus 22.2 g/d), protein (33.1 versus 20.3 g/d) and lactose (22.4 versus 13.9). In conclusion, probiotics barely affected blood plasma metabolite contents and enzyme activities, but positive effects on milk yield and its components were observed during the last third of lactation. Further research would be needed to determine whether the supplementation of ewe diet with probiotics is advisable for sustainable livestock farming systems.