Effects of dietary supplements of algae, containing polyunsaturated fatty acids, on milk yield and the composition of milk products in dairy ewes

Abstract

Thirty-two lactating Karagouniko ewes were allocated at random to four groups for 6 weeks, to examine the effect of four diets: C (control treatment, ration without algae); LA (ration with low level of algae); MA (ration with medium level of algae) and HA (ration with high level of algae); containing 0, 23·5, 47 and 94 g algae, respectively, on the enrichment of milk and dairy products. Addition of algae reduced (P<0·001) DM intake for treatments MA and HA. Milk yield did not differ between treatments but milk composition was significantly affected by dietary inclusion of algae. Milk fat content was significantly increased (P<0·001) for treatment HA whereas milk protein content was significantly increased (P<0·001) for all treatments containing algae. Milk from treatments LA, MA and HA was significantly enriched in the following PUFA: C20[ratio ]5 (n-3) (0·4–2·1%), C22[ratio ]5 (n-6) (0·8–4·1%), C22[ratio ]6 (n-3) (4·3–12·4%) (P<0·001) and C22[ratio ]5 (n-3) (2·1–3·1%) (P<0·05), which were not detected in control milk. Feta cheese and yogurts produced from the enriched milk had identical composition with the milk, and would be characterized as healthy foods. The ratio of n-6 to n-3 fatty acids was 2·5–4·5.

Feeding strategies to design the fatty acid profile of sheep milk and cheese

“…In addition, the evaluated dairy products, i.e., feta cheese and yogurt, had a similar polyunsaturated FA profile to that of the EPA-and DHAenriched milk (Papadopoulos et al, 2002), evidencing that the milk processing did not alter the concentration of this LC-FA of nutritional interest. This is also supported by our data on DHA content in milk, cheese and ricotta sampled from two processing plants in Northern Sardinia from March to June 2004 (Figure 3), which evidenced that the DHA in dairy products reflects the FA composition of raw milk used for cheese making.…”

“…In lactating ewes, there was a linear increase in milk EPA (from 4 to 21 g/kg) and DHA (from 43 to 124 g/kg) content as the dose of algae in the diet increased (23.5, 47 and 94 g/d), whereas those FA were not detected in the milk from control ewes (Papadopoulos et al, 2002). In addition, the evaluated dairy products, i.e., feta cheese and yogurt, had a similar polyunsaturated FA profile to that of the EPA-and DHAenriched milk (Papadopoulos et al, 2002), evidencing that the milk processing did not alter the concentration of this LC-FA of nutritional interest.…”

Effect of micro-alga supplementation on goat and cow milk fatty acid composition

“…Papadopoulos et al (2002) reported that ewe milk fat and protein contents were significantly increased for treatment containing algae. In dairy cows, 7.4 g kg -1 DMI of micro-algae supplementation has slightly negative effect on rumen fermentation; it results reduced fermentation in order to decrease fat content and concentrations of C4:0, C6:0 and C8:0 fatty acids of cow milk.…”

“…While n-6 enriched diet (such as sunflower) unmodified or increased the milk composition in both species (Dai et al, 2011;Martínez et al, 2012). Several studies investigated the effects of diet, such as green forages (Tsiplakou et al, 2006;Pajor et al, 2009) or oilseeds (Brzóska, 2006) on fatty acids, however, data on feeding micro-alga supplements are limited (mainly in dairy cows and ewes, such as Boeckaert et al, 2008;Papadopoulos et al, 2002 andToral et al, 2010, respectively). Spirulina platensis and Chlorella kessleri are freshwater micro-algae species.…”

Consolidated Properties and New Perspectives for Polyunsaturated Fatty Acids in Ruminant Diet

“…12 Other aspects, both economic and environmental, have to be taken in account when using fish oil as a source of n-3 PUFA, such as the relevant cost and the sustainability of fish stocks. 1 Therefore, it is crucial to consider alternative sources, for example marine algae rich in DHA, 8,13,14 linseed 15 and camelina 16,17 both rich in C18:3 n-3 (ALA, alpha-linolenic acid), the precursor for EPA and DHA. Another natural dietary source of n-3 PUFA is green pasture.…”